Ecological importance of sedges: a survey of the Australasian Cyperaceae genus Lepidosperma

Abstract

Background

Sedges (Cyperaceae) form an important ecological component of many ecosystems around the world. Sword and rapier sedges (genus Lepidosperma) are common and widespread components of the southern Australian and New Zealand floras, also occurring in New Caledonia, West Papua, Borneo, Malaysia and southern China. Sedge ecology is seldom studied and no comprehensive review of sedge ecology exists. Lepidosperma is unusual in the Cyperaceae with the majority of species occurring in dryland habitats.

Scope

Extensive review of ecological literature and field observations shows Lepidosperma species to be important components of many ecosystems, often dominating understorey and sedge-rich communities. For the first time, a detailed ecological review of a Cyperaceae genus is presented.

Conclusions Lepidosperma

species are long-lived perennials with significant abundance and persistence in the landscape. Speciation patterns in the genus are of considerable interest due to complex biogeographical patterns and a high degree of habitat specificity. Potential benefits exist for medicinal products identified from several Lepidosperma species. Over 178 organisms, including 26 mammals, 42 birds, six reptiles, five amphibians, eight arachnids, 75 insects, three crustaceans and 13 fungi, are found to be dependent on, or making use of, Lepidosperma species. A significant relationship exists between Lepidosperma species and the moth genus Elachista. Implications for the conservation and ecology of both sedges and associated species are discussed.

INTRODUCTION

‘Owing to the lack of detailed information, much more study is necessary before our knowledge of the part played by the Cyperaceae in the make-up of the communities can be adequately assessed in relation to other important families.’ (Diels, 1906, transl. 2007)

Sedges (Cyperaceae) are a large, cosmopolitan family of global ecological and economic significance (Simpson and Inglis, 2001). Sedges form a major component of most wetland vegetation units around the world and make an enormous contribution to nutrient cycling and habitat formation in these ecosystems (Harper, 1992; Chambers et al., 2008). Carex, with up to 2000 species, is one of the world's largest genera with a distribution and great significance in wetlands and seasonally damp habitats around the world (Govaerts et al., 2007; Waterway and Starr, 2008). Cyperus, with around 600 species, is another well-known genus that includes important economic and horticultural species (Goetghebeur, 1998; Simpson and Inglis, 2001). Cyperus papyrus is the earliest known plant used for making paper, in use as early as 3000 bc, and continuing in common use until 200 ad. Papyrus largely replaced animal skin parchments and stone for writing and had a profound impact on human society, being instrumental in the development of efficient communication systems (Parkinson and Quirke, 1995; Newton, 2009).

Many species of Cyperaceae tribe Schoeneae occur in dryland habitats that are only seasonally damp (e.g. woodland and heath communities; Goetghebeur, 1998). This is an unusual habitat in a family that is predominantly comprised of genera and species which occur in wetlands and damp areas. A summary of habitat preference or specificity is presented for Lepidosperma species in Table 1. Temperate Australia and Africa both have a large number of dryland sedges, particularly in the genera Afrotrilepis, Carpha, Caustis, Coleochloa, Costularia, Cyathochaeta, Gahnia, Lepidosperma, Mesomelaena, Microdracoides, Schoenus, Tetraria (sensu lato, s.l.), Tetrariopsis and Tricostularia (Goetghebeur, 1998; Linder, 2003; Shane et al., 2005; Helme and Trinder-Smith, 2006; Slingsby and Verboom, 2006). A smaller number of genera and species occupy dryland habitats in central and northern Africa and South America where they are often found on granite inselbergs (Haines and Lye, 1983; Goetghebeur, 1998; Porembski, 2006; Beentje and Ghazanfar, 2010). The predominance of dryland species in these bioregions suggests the possibility of different patterns of speciation relative to the younger geological landscapes common in the northern hemisphere (Hopper, 2009; Lambers et al., 2010).

Table 1.

Ecological niche occupied by Lepidosperma species; records are based on notes from herbarium voucher specimens and personal observations

Niche	Lepidosperma species
Hygrophilous (moisture-loving)	L. australe, L. chinense, L. effusum, L. elatius (in part), L. filiforme (in part), L. forsythii, L. gladiatum (in part), L. limicola, L. longitudinale, L. persecans (in part), L. quadrangulatum, L. rostratum, L. striatum, L. tetraquetrum (strict rheophyte?), L. sp. Blackwood (R. Davis 7696), L. sp. Bluff Knoll robust (G.J. Keighery 12595), L. sp. Z dark sheath (P.G. Wilson 10177)
Petrophilous (rock-loving)	L. amantiferrum, L. angustatum, L. avium, L. bungalbin, L. clipeicola, L. concavum, L. ferricola, L. ferriculmen, L. gibsonii, L. gracile, L. jacksonense, L. lyonsii, L. resinosum, L. rupestre, L. tuberculatum, L. tuberculatum var. grande, L. sp. Billyacatting (S.D. Hopper 8630), L. sp. Blue Hills (A. Markey & S. Dillon 3468), L. sp. Giant Terete Culms (S.D. Hopper 8631), L. sp. Gosnells (A. Markey 1145), L. sp. Kambalda (A.A. Mitchell 5156), L. sp. Moresby Range (R.J. Cranfield 2751), L. sp. Mt Caudan (N. Gibson & M. Lyons 2081), L. sp. Mt Ragged (K. Newbey 7858), L. sp. Parker Range (N. Gibson & M. Lyons 2094), L. sp. Peak Charles fine (K. Newbey 5411), L. sp. Pigeon Rocks (H. Pringle 30237), L. sp. Wolga Rock (S.D. Hopper 6513)
Cremnophilous (cliff faces)	L. evansianum, L. ferricola (in part)
Arenophilous (sand-loving)	L. canescens, L. carphoides, L. rigidulum, L. scabrum
Seasonally xerophilous (areas of low water availability)/ seasonally mesophilous (moderate growing conditions)	L. asperatum, L. benthamianum, L. congestum, L. costale, L. curtisiae, L. diurnum, L. drummondii, L. filiforme, L. fimbriatum, L. flexuosum, L. gahnioides, L. globosum, L. humile, L. inops, L. laeve, L. latens, L. laterale (in part), L. leptophyllum, L. leptostachyum, L. lineare, L. neesii, L. neozelandicum, L. obtusum, L. oldfieldii, L. pauperum, L. perplanum, L. perteres, L. pruinosum, L. pubisquameum, L. sanguinolentum, L. sieberi, L. squamatum, L. tenue, L. tortuosum, L. urophorum, L. ustulatum, L. viscidum, L. sp. Archer Drive (S. Kern & R. Jasper LCH 18300), L. sp. Bandalup Scabrid (N. Evelegh 10798), L. sp. Bluff Knoll scabrid (K.H. Rechinger 60431), L. sp. Carracarrup Creek (S. Kern et al., LCH 16738), L. sp. Elverdton (R. Jasper et al. LCH 16844), L. sp. Gingin (M.A. Langley & P.M. Smith MAL 2193), L. sp. Hopetoun Road (S. Kern et al. LCH 16552), L. sp. Maydon (S. Kern, R. Jasper, H. Hughes LCH 17844), L. sp. Meckering (R.Davis WW27-32,) L. sp. Mt Burdett (M.A. Burgman & C. Layman MAB 3287), L. sp. Mt Chester (S. Kern et al. LCH 16596), L. sp. Mt Groper (K. Newbey 11808), L. sp. Mt Short (S. Kern et al. LCH 17510), L. sp. P1 small head (M.D. Tindale 166A), L. sp. Ravensthorpe (G.F. Craig 5188), L. sp. Saltbush Hill (K.R. Newbey 4118), L. sp. Shoemaker Levy (L. Ang & O. Davies 10815), L. sp. Steere River (S. Kern, R. Jasper, H. Hughes LCH 17764), L. sp. U1 big heads (A.S. George 11294), L. sp. Zuytdorp (G.J. Keighery & N. Gibson 1710)
Wet forests	L. elatius, L. ensiforme, L. laterale (in part), L. persecans, L. sp. Manypeaks large (R. L. Barrett RLB 2476), L. sp. Margaret River (B.J. Lepschi 1841)
Coastal dunes	L. gladiatum, L. sp. Coastal Dunes (R.J.Cranfield 9963)
Subalpine	L. chinense (in part), L. filiforme (in part), L. inops (in part), L. tortuosum (in part)

Although less well known, the sword and rapier sedges, Lepidosperma, are a significant plant genus in many temperate ecosystems of Australasia and the genus also extends to South East Asia. The majority of literature, and thus the majority of this review, is focused on Australian and New Zealand species, but all species are included here. Lepidosperma concavum was among the earliest collections of Australian plants, that of Banks and Solander from Botany Bay in 1770 (Benson and Eldershaw, 2007). Lepidosperma species regularly dominate the understorey of a wide range of dryland habitats throughout their range and may also be important components of wetland and riverine environments in southern Australia and New Zealand (Specht, 1972; Atkinson, 1984, 2004; Fensham, 1989; Beard, 1990; Conn, 1993; Usback and James, 1993; Kirkpatrick, 1997; Pen et al., 2000; Keith, 2004; Berkinshaw, 2009).

Taxonomic nomenclature has been reviewed by Barrett and Wilson (2012), with 73 validly named species currently published. An additional 41 putative species are currently listed as provisional polynomial taxa on the Western Australian Herbarium website FloraBase (1998 onwards) following the protocol outlined by Barker (2005). This listing provides legislative protection for taxa that are yet to be formally named. Taxonomic revision of the genus is currently underway by R. L. Barrett, K. L. Wilson, J. J. Bruhl and colleagues. With the total number of species in the genus estimated at well over 200, Lepidosperma is one of the larger genera in the Australasian flora and the largest genus of Cyperaceae in the region (Barrett, 2012). In the global biodiversity hotspot of southern Western Australia, the genus is probably one of the five largest, behind Acacia and Eucalyptus, with similar numbers to Grevillea and Stylidium (Beard et al., 2000; Hopper and Gioia, 2004; J. Wege, pers. comm.; R. L. Barrett unpubl. data). Lepidosperma belongs to Cyperaceae tribe Schoeneae and is most closely related to Machaerina (including Baumea), Neesenbeckia and Tetraria p.p. (T. capillaris; Verboom, 2006). Lepidosperma can be readily defined by the persistent, thickened, hypogynous scales at the base of the nutlet (Bruhl, 1995). The culms are scapose and the leaves are (spiro)distichous in arrangement.

Given the ecological predominance of the genus in many parts of its range and the poorly resolved taxonomy, a review was conducted to determine what is known about the genus Lepidosperma, and its relative importance in community ecology. Emphasis is placed on how other organisms relate to Lepidosperma species in a community ecology setting. The opportunity is also taken to correct the literature (where possible) with updated nomenclature for the Lepidosperma species involved, as names have commonly been misapplied and correct application of names can have important implications for conservation efforts. This review attempts to answer the questions of ‘are sedges important?’ and ‘do individual sedge species matter?’

METHODS

This paper primarily reviews knowledge available in reviewed scientific literature, books and academic theses. Additional unpublished observations are reported here for the first time. An introduction to the ecological attributes of Lepidosperma is given where those attributes may be applicable to understanding the conservation implications for management of ecological communities containing Lepidosperma species. Details are then provided of the organisms that are known to have ecological associations with the genus Lepidosperma. Incidental co-occurrence is largely ignored; however, co-occurrence is considered significant when Lepidosperma species are a characteristic component of the ecosystem, or specifically mentioned as a species of significance.

Nomenclature follows the original sources unless otherwise indicated by an alternative name. While attempts have been made to ensure that all names listed here are current, some may now be considered synonyms or placed in alternative genera. Application of names in Lepidosperma follows Barrett and Wilson (2012).

ECOLOGICAL CHARACTERISTICS

Habitat specificity

Some Lepidosperma species show marked geological specificity and numerous endemic species have been located on banded ironstone formations (Gibson and Lyons, 1998a, b, 2001; Gibson, 2004a, b; Barrett, 2007a; Gibson et al., 2007, 2010; Fig. 1), granite outcrops (McKenzie et al., 2004; Fig. 2), dolerite outcrops (Wilson, 1994) and numerous other geological formations, usually on shallow soils (Barrett, 2007b; Barrett et al., 2009; R. L. Barrett pers. obs., Fig. 3).

Fig. 1.

(A) Lepidosperma sp. Honman Ridge (R. L. Barrett & M. Wallace RLB 4120) on banded ironstone formation, Honman Ridge, Great Western Woodlands, Western Australia. (B) Roots of Lepidosperma gibsonii that were growing under a flat slab of banded ironstone, Mount Gibson, Western Australia. (C) Lepidosperma gibsonii growing in massive banded ironstone.

Fig. 2.

Granite outcrops providing rich habitats and refuge areas for Lepidosperma species in the wheatbelt of Western Australia. (A) Chiddarcooping Nature Reserve. (B) Gathercole Nature Reserve.

Fig. 3.

(A) A rare cremnophytic species, Lepidosperma evansianum, at Wentworth Falls in the Blue Mountains National Park, New South Wales. (B) The widespread Lepidosperma filiforme partly covered by a summer snowfall on the summit of Mount Field in the Tasmanian highlands. (C) Lepidosperma sp. Southern Granite beside a gnamma (vernal pool) on Mt Lindesay, near Denmark, Western Australia. (D) Lepidosperma congestum and L. viscidum in windswept coastal heath south of Port Lincoln, South Australia.

Lepidosperma species are common components of vegetation containing rare plant species (e.g. Lynch, 1999; Benson and Allen, 2007; Bell, 2008; Stack et al., 2008). They also occur in intrinsically rare habitats (Gibson et al., 2000, 2007). Temperate Australian peat soils are largely derived from rushes and sedges, including Lepidosperma, and are an important habitat for many species including Sphagnum. These ecosystems are increasingly threatened by land-use activities and climate change (Whinam et al., 2001) and are poorly represented in conservation reserves (Specht et al., 1995). A lichen species (Heterodea muelleri) that was considered extinct in New Zealand was recently located on the Chatham Islands where it grows in association with Lepidosperma australe (de Lange, 2009).

The ecological distribution of Lepidosperma species is detailed in Table 1: 16 are hygrophilous (moisture-loving), 29 are petrophilous (rock-loving), two are cremnophilous (cliff-loving), four are arenophilous (sand-loving), 58 are generalist seasonally xerophilous (areas of low water availability)/seasonally mesic (moderate growing conditions), six are from wet forests, two occur on coastal sand dunes and four extend to subalpine zones. Most Lepidosperma species are seasonally xerophilous, such as the widespread L. sanguinolentum in southern Western Australia, which grows on extensive sandplains from Ravensthorpe on the south coast, north to Geraldton on the west coast, and inland to Queen Victoria Spring on the edge of the Queen Victoria Desert. A broad view of xerophyly is taken here to include habitats that are seasonally mesic, but have a longer seasonally xeric period, including woodlands and heath habitats. In the south western interzone of Western Australia, Lepidosperma species are commonly restricted to rock outcrops, where they may be locally common on granite or banded ironstone formations (Barrett, 2007a). Species such as L. bungalbin, L. gibsonii, L. jacksonense and L. lyonsii all grow on isolated rocky ranges in the Western Australian Goldfields and Murchison districts, surviving there by means of increased runoff from sporadic rainfall events (Barrett, 2007a). In the Die Hardy Ranges, north of Southern Cross, Western Australia, L. ferricola grows in fissures on banded ironstone cliff faces, occupying a niche also occupied by rare species of Tetratheca (Elaeocarpaceae) (Barrett, 2007a; Butcher et al., 2007). Lepidosperma avium is a relictual species endemic to the Everard Ranges in the arid north-west of South Australia (Wilson, 1994; Barrett, 2012). Lepidosperma laterale (s.l.) is a very widespread species complex which occurs in woodlands and forests from eastern regions of South Australia, throughout much of Victoria and Tasmania, and north along the Great Dividing Range and coastal areas of New South Wales and Queensland, extending as far as the Iron Range on Cape York Peninsula, spanning 31 degrees in latitude and 43 degrees in longitude (Barrett and Wilson, 2012). This species complex also occurs in New Zealand and New Caledonia, presumably as a result of long-distance dispersal events.

Lepidosperma species can be numerous and particularly common around granite outcrops, often dominating the understorey (Ashton and Webb, 1977; Hopper et al., 1997; Pigott and Sage, 1997; Hunter and Clarke, 1998; McKenzie et al., 2004). Granite rocks may act as important refugial habitats, largely due to their ability to ‘harvest’ small quantities of water, forming water-accumulating microsites and thus providing a relatively stable ecosystem in areas that may otherwise have unpredictable or low rainfall (York Main, 1997). Water accumulation zones on and around rock outcrops provide important habitats for a large number of Lepidosperma species. Granite outcrops in eastern Australia also act as ‘islands’ for speciation (McGann, 2002) and locally endemic Lepidosperma species are now coming to light on inselbergs on the New England Tableland (J. J. Bruhl and R.L. Barrett, pers. obs.). A similar pattern is also observable in south-western Australia (R. L. Barrett and S. D. Hopper, pers. obs.).

Wilson (1986) reviewed the Australian Cyperaceae occurring in alpine zones but did not list any Lepidosperma species. Lepidosperma chinense, L. filiforme, L. inops (s.l.) and L. tortuosum all occur in subalpine zones over parts of their respective ranges. Horsnell et al. (2009) record Lepidosperma ‘viscidum’ as being both a xerophyte and a hygrophyte, occurring in areas containing wetlands that were subject to salinization along the south coast of Western Australia. It is most likely that they are actually referring to two currently unnamed taxa with affinity to L. squamatum that have distinct habitat preferences (R. L. Barrett, pers. obs.). Many additional species are yet to be formally named, the majority of which are petrophilous or generalist xerophilous species. A few species of Lepidosperma are hygrophilous and these are often better studied, as wetland habitats are more regularly threatened than xeric habitats, and these species are discussed here in more detail. More studies of the xerophilous species are required to balance our understanding of the genus.

Lepidosperma australe regularly grows in seasonally waterlogged soils where the roots have been recorded to be continuously under water for up to 270 d without any apparent detrimental effects (Johnson, 1972). Lloyd et al. (2000) suggest that L. australe is most abundant in ecotone sites near seasonally wet areas, although it also extends beyond the wet margins onto dune slacks (Roxburgh et al., 1994). Robertson et al. (1991) consider L. australe to be an early colonizer species on the margins of lakes. It grows with other sedges and promotes the accumulation of soil and litter at the lake margin, eventually providing a suitable substrate for larger shrubs and trees. Lepidosperma filiforme is a common component of sedgelands in Tasmania (Harris and Kitchener, 2005) and L. neozelandicum is common in wet heathlands (gumlands) in the far north of New Zealand (Clarkson et al., 2011). Lepidosperma longitudinale is found in areas of impeded drainage across southern Australia where it may form very dense stands, dominating the understorey (Brown et al., 1982); however, it only tolerates partial seasonal inundation (Froend et al., 1993). Lepidosperma longitudinale, L. gladiatum and in some cases L. effusum and L. persecans are common species in numerous wetlands of national significance in Australia (Usback and James, 1993; Jacobs, 1999). Fringing vegetation such as dense communities of L. effusum and L. tetraquetrum serve to slow water flow during flood events and provide stability to the margins of waterways (Pen, 1999).

Lepidosperma elatius is a common species in wet forests in south-eastern Australia. In a study of flood-maintained vegetation patterns in south-eastern Tasmania, Wintle and Kirkpatrick (2007) found that L. elatius occurs in depositional areas of drainage lines where it plays an important role in trapping debris and sediment. Lepidosperma species occurring in swamp habitats can be significant contributors to the development of peat soils due to their high biomass production (Green et al., 1988).

Perhaps due to their local dominance and habitat or substrate specificity, Lepidosperma species have often been found to be important defining members of plant communities (e.g. Kirkpatrick, 1981; Griffin et al., 1983; Atkinson, 1984; Fensham, 1989; Groves, 1999; Tozer, 2003; Keith, 2004; Harris and Kitchener, 2005; Hunter and Bell, 2007; Craig et al., 2008; Sandiford and Barrett, 2010). Bridgewater (1978) proposed a vegetation alliance ‘Lepidospermion’ on coastal dunes in Victoria where Lepidosperma species are prominent and Adam et al. (1989) recognized a similar vegetation association in New South Wales. There is some evidence that community boundaries may be particularly influenced by phosphorus concentrations in the soil (Ashton, 1976), and Hogg and Kirkpatrick (1974) demonstrated a specific association of L. laterale with dolerite and mudstone in Tasmania. Brown et al. (1982) found that L. filiforme in south-western Tasmania is most common at sites with low soil pH, although tolerant of a wide soil pH range (4·3–8·7), while L. longitudinale is usually found in locations with a pH of about 7·5.

Chemistry and medicinal properties

There has been very limited investigation of the chemical properties of Lepidosperma tissues. Aplin and Cannon (1971) assessed three Western Australian Lepidosperma species and found that they lacked alkaloids. Kükkonen (1971) identified six different flavonoid compounds in L. concavum but did not identify the individual compounds present. Williams and Harborne (1977) conducted a survey of flavonoid chemistry in Cyperaceae and found that L. tortuosum contained quercetin. In further studies, Harborne et al. (1985) surveyed 16 Lepidosperma species for the presence of flavonoids and found that flavonols were common in Lepidosperma species and included some yellow aurone pigments and an anthocyanin-type pigment, carexidin. Harborne et al. (1985) considered that Lepidosperma can be well characterized chemically by the presence of tricin, quercetin and isorhamnetin, while mostly lacking luteolin and aurones, the latter being present rarely in some species. Pigmentation can play an important role in photoprotection, a factor especially important in species occupying xeric environments (Steyn et al., 2002). Flavonoids play particular roles in plant defence, often deterring herbivores from feeding on the plants (Simmonds, 2001; Morimoto and Komai, 2006). The presence of two potentially allelopathic chemicals (cyperotundone and α-cyperone) has been explored in Cyperus rotundus by Morimoto and Komai (2005) but it is unknown whether these chemicals are more widespread in the Cyperaceae and whether they might be found in Lepidosperma species.

Naturally derived pharmaceutical products remain the primary source of new medicinal drugs and analysis of new plant-derived compounds remains an important part of modern medical research (Newman et al., 2008). Gott (1993) reported the traditional use of the stem bases of L. gladiatum and L. viscidum for use against colds by Aboriginal people in South Australia. This has been investigated by Semple et al. (1998) and Palombo and Semple (2001) who investigated the antibacterial properties of these species, finding that extracts of L. gladiatum and L. viscidum were both active against a range of Gram-positive bacteria. Palombo and Semple (2002) conducted further tests with the most active species, L. viscidum, and found activity against methicillin-resistant Staphylococcus aureus (MRSA) and partial activity against vancomycin-resistant Enterococcus (VRE). Meilak and Palombo (2008) investigated L. viscidum for potential activity against Mycobacterium fortuitum and M. smegmatis but no significant effect was found. A significant amount of work has been undertaken to isolate stilbenes, including chemical analogues of resveratrol, from Scleria holoschoenus (Abdel-Mogib et al., 2001) and a number of Carex species (see González-Sarrías et al., 2011). Resveratrol is a well-known constituent of red wine that has shown benefits in reducing the risk of heart disease and possesses anti-cancer and anti-ageing properties (González-Sarrías et al., 2011). Recently, novel stilbenes have also been isolated from a Lepidosperma species in South Australia and their potential medical benefits are the subject of ongoing research (Duke et al., 2012).

Nutrient acquisition

Cyperaceae are recognized for their ability to colonize a diverse range of habitats. Their prevalence in dry shrublands and woodlands in Australia may in part be explained by their ability to extract phosphorus from nutrient-poor soils. Cluster roots were first described in Cyperaceae by Renner (1935). The production of these specialized root structures in Carex is documented by Selivanov and Utemova (1969) who confused them for mycorrhizal structures. Lamont (1974, 1981, 1982, 1983, 1984) further defined the root type as ‘dauciform roots’ and characterized their ability to enhance nutrient uptake in Cyathochaeta, Gahnia, Lepidosperma and Schoenus. More recent work has shown that many genera and species in Cyperaceae tribes Schoeneae (including Lepidosperma) and Cariceae have the ability to develop such dauciform roots and they may be present in all species in the tribe Schoeneae (Raab et al., 1999; Shane and Lambers, 2005; Shane et al., 2005; Yano et al., 2011).

The dauciform roots of Lepidosperma are among the largest produced in the Cyperaceae (Lambers et al., 2006; Fig. 4). Production of dauciform roots in Lepidosperma is induced by low availability of phosphorus and results in the production of elongated cells that release carboxylates in an exudative burst (Shane et al., 2006). Carboxylates promote the release of soil-bound phosphorus (Shane et al., 2005; Watt and Weston, 2009). The full range of conditions is yet to be determined (Miller, 2005; Shane et al., 2005; Playsted et al., 2006) and Bakker et al. (2005) found that the addition of phosphorus did not influence the production of dauciform roots in Schoenus nigricans.

Fig. 4.

Dauciform roots of Lepidosperma longitudinale (western form), from Bold Park, Western Australia (photos: Mike Shane).

In addition to dauciform roots, some Lepidosperma species also commonly develop sand-binding roots that can serve to stabilize surrounding soil and aid water uptake and retention (Dodd et al., 1984). The ecological role of these sand binding roots has been explored in detail for the morphologically similar Lyginia barbata (Anarthriaceae; Shane et al., 2009, 2010, 2011). Similar studies should be undertaken in Lepidosperma and allied genera.

While studying the natural abundance of nitrogen in Banksia woodland ecosystems, Lepidosperma sp. Coastal Dunes was shown to have a relatively low level of shoot nitrate reductase (about 40 pkat. per g f. wt) and corresponding low δ¹⁵N (about 1; Pate et al., 1993; Pate, 1994; as L. angustatum). Nitrate is an important macronutrient and plays a vital role in growth (Crawford and Glass, 1998). The low level of shoot nitrate reductase found by Pate et al. (1993) may indicate that Lepidosperma species preferentially use organic nitrogen as found for the Arctic sedge Eriophorum vaginatum by Chapin et al. (1993).

Bowman et al. (1986) studied mineral and nutrient uptake and mobilization by plants across a landscape in south-western Tasmania, finding that L. filiforme had foliar concentrations of 113 µg g⁻¹ phosphorus, 4100 µg g⁻¹ potassium, 950 µg g⁻¹ sodium, 950 µg g⁻¹ calcium and 540 µg g⁻¹ magnesium. This species was able to withdraw 93 % of phosphorus and potassium, 58 % of sodium and 18 % magnesium prior to leaf senescence. Such a high level of internal nutrient recycling means that Lepidosperma species are well adapted to survival in low-nutrient soils.

Studies by Jones (1968) suggested that the addition of fertilizer to natural stands of L. sieberi (as L. concavum) had no significant impact on growth rate over two years. However, results of studies on the effect of overstorey thinning and fertilization for L. urophurum suggest that many respond positively to the addition of fertilizer (Bauhus et al., 2001). Bridle and Kirkpatrick (2003) investigated the impacts of human and animal waste on plant growth and found that the addition of urine increased the cover of L. sieberi (as L. concavum).

Ultramafic/serpentine substrates

Serpentine soils are derived from ultramafic parent rock. They are defined by the presence of extreme mineral concentrations, commonly low calcium, phosphorus and potassium, and high magnesium and nickel (Nagy and Proctor, 1997). Plants occurring on these ultramafic/serpentine substrates often have specific adaptive strategies to deal with mineral toxicity and nutrient deprivation (Nagy and Proctor, 1997; Proctor, 2003). Relatively little is known about floristic communities on ultramafic soils in Australia, despite the presence of a number of species endemic to these communities (Gibson et al., 1992). There is considerable interest in the flora of ultramafic soils in southern Western Australia, particularly on Bandalup Hill, near Ravensthorpe. This hill and the associated Ravensthorpe Range show very high levels of floristic diversity with a high level of local endemism and rarity (Kern et al., 2008). A detailed assessment of Lepidosperma taxa from the Ravensthorpe Range and Bandalup Hill showed that 42 species should be recognized from this area, only five of which are currently named (Barrett et al., 2009). About half of these taxa are locally endemic and 18 of these require conservation assessments to determine whether they should be listed as rare or threatened (Barrett et al., 2009). This geographical region has by far the highest diversity for the genus Lepidosperma, and also has a large number of species in genera such as Eucalyptus and Melaleuca (Kern et al., 2008). The Ravensthorpe Range has a very diverse and complex geological history and this is thought to be one of the reasons for the range's high levels of floristic diversity. Kruckeburg (1986) has suggested that unusual geologies may often act as opportunities for speciation as plants adapt to particular substrates and become unfit outside their particular niche. Speciation across geological boundaries may occur even with continued outcrossing if the out-crossed progeny from the alternative geological parent fail to survive. As a result, a number of closely related species may be found in unusually close proximity in geologically diverse locations (Heslop-Harrison, 1964).

An unidentified Lepidosperma species from south-east Queensland was found to grow effectively in metal-rich soils, absorbing significant amounts of copper and arsenic, and some silver, cadmium, molybdenum, lead and zinc (Ashley et al., 2003). Lepidosperma australe has been recorded as a significant gold-accumulating species in New Zealand where it may have potential as an indicator species for gold prospecting (Ward and Brooks, 1978).

Lepidosperma laterale and L. perteres are locally common in ultrabasic massifs of New Caledonia (Jaffré, 1974). Within New Caledonia, L. pauperum and L. perplanum are both restricted to ultrabasic soils, while L. perteres is not restricted to specific soil types (Morat et al., 1986). Nutrient acquisition varies with soil type, with Jaffré (1976) demonstrating that L. perteres is able to take up significantly higher amounts of nitrogen and potassium from ferrous soils than from brown soils in New Caledonia. The uptake of manganese from ferrous soils was ten-fold greater than that from brown soils while uptake of magnesium from ferrous soils was significantly reduced. There was also a ten-fold reduction in the uptake of silicon from ferrous soils (Jaffré, 1976).

Fire and disturbance response

Long-term survival in ecosystems prone to disturbance or environmental fluctuations is primarily determined by the ability to persist and reproduce. Plants that have the ability to resprout following disturbance events such as fire or grazing tend to allocate greater resources to below-ground biomass than to sexual reproduction, with lower seedling recruitment rates but long generation times (Bond and Midgley, 2003). These characteristics are true of most Lepidosperma species. All Lepidosperma species are clonal perennials and most have been observed in the field by the author. These observations have shown that clones vary in size, from around 5–10 cm for L. inops to over 10 m for L. gladiatum. These clones provide a robust resource to withstand disturbance events and periods of low rainfall. Explicit data on the age of individual clones are not available, but assessment of clone size against annual growth rates suggests that plants of most species probably live for at least 50 years, and some clones are estimated to be in excess of 100 years old (R. L. Barrett, pers. obs.). Such longevity of individuals and resilience to disturbance means that Lepidosperma species can survive with very low recruitment rates and persist in some extreme environments. Given their persistence, they can form a very significant and stable component of the ecosystems in which they occur.

Specht (1981) classifies Lepidosperma species as evergreen hemicryptophytes. Almost all Australian Lepidosperma species that have been observed post-fire have shown capacity to resprout from rhizomes, with vegetative growth rapidly re-establishing or exceeding pre-fire biomass (Bradstock et al., 1997; Ashton, 2000; Barrett, 2000; Hopper, 2000; Brown et al., 2002; Morrison, 2002; R. L. Barrett, pers. obs.). In Lepidosperma, rhizome resources are often sufficient for flowering to occur in the first year following fire (Hopper, 2003; provided the burn season allows for floral initiation and development). Long-term monitoring of L. elatius in wet forests at Wallaby Creek in Victoria revealed a significant increase in density over a period of 50 years in response to the maturation and eventual decline of the eucalypt canopy in the absence of fire (Ashton, 2000). Lepidosperma limicola, a common species in sedge swamps in the Gibraltar Range of New South Wales, was equally abundant in burnt and unburnt sites (Williams and Clarke, 2006). In contrast, it should be noted that some populations of L. filiforme (?= L. flexuosum) in the Sydney region appear to be killed by fire, regenerating only from seed (Kubiak, 2009; R. L. Barrett and K. L. Wilson, pers. obs.). This is possibly due to the relatively shallow rhizomes and habitat in dense heath that is likely to promote hot fires (R. L. Barrett and K. L. Wilson, pers. obs.).

While able to resprout following fire, a form of L. laterale from north-eastern Queensland montane heath communities significantly decreased in abundance following fire, probably due to biomass reduction in a nutrient-limited environment limiting short-term recovery (Williams et al., 2005). Careful fire management was advised to ensure that fire frequency did not have a detrimental impact on this species. Correct classification of the fire response of each species is essential for sustainable management, particularly for rare or ecologically critical species (Gill and Bradstock, 1992). Cary and Morrison (1995) found that L. laterale is one of the few species in sandstone communities in the Sydney region that is able to tolerate high fire frequency (<5 years between fires). Adult plants are able to reproduce and seedlings are able to recruit and persist under these conditions, which may be promoting germination. Lepidosperma laterale also increased in cover following fire on Fraser Island, more so after low- rather than high-frequency fires (Spencer and Baxter, 2006).

Lepidosperma leptostachyum declined in abundance by at least 20 % under a variety of fire regimes in jarrah forest near Manjimup in Western Australia (Burrows and Wardell-Johnson, 2003). They suggested this decline was possibly due to decreasing rainfall patterns. This species has relatively shallow rhizomes that are often close to the litter layer and there may be a high level of mortality for this reason, particularly from hot fires. They also showed a decline in abundance of L. squamatum (s.l.) following spring fires that had an interval of 7–9 years.

Lepidosperma perteres from New Caledonia is rhizomatous and is able to resprout vigorously following fire, often dominating post-fire maquis vegetation (Jaffré et al., 1998). However, it may be negatively affected by frequent fires, which can promote the dominance of other plant species (McCoy et al., 1999). The prevalence of L. chinense in some grasslands in Hong Kong is also attributed to the promotion of fire in these areas (Kadoorie Farm and Botanic Garden, 2003).

Tozer and Auld (2006) measured the degree of leaf scorch in L. neesii in the Sydney region following fire. Their study showed that fire penetration was always less than the depth of the meristematic tissue, thus allowing the plants to resprout following fire. Lepidosperma neesii shows very strong preference for seasonally dry sites with low shade cover, decreasing in abundance in dry shaded areas, decreasing further in moist open areas and becoming very sparse in moist shaded areas (Tozer and Bradstock, 2003). This pattern of habitat preference corresponds to litter levels that provide fuel for fires.

Some Lepidosperma species are readily able to recover from disturbance. Ough (2001) found that L. elatius recovered with equal frequency following both clear-fell logging and wildfire, although total cover of this species was lower in the wildfire site. Partial habitat disturbance due to the development of log removal tracks for timber harvesting in Tasmanian forests had little impact on the density of L. sieberi (as L. concavum; Williamson and Neilsen, 2003). In contrast, Loyn et al. (1983) found that in East Gippsland, L. laterale increased in abundance following fire, but decreased in abundance in areas harvested for timber. Density of L. leptostachyum plants declined following logging operations in south-western Western Australia (Burrows et al., 2002). In urban locations, Lepidosperma species can show remarkable resilience. Rose and Fairweather (1997) found that L. filiforme, L. laterale and L. lineare (as L. gunnii) were all able to persist in the long term in urban bushland invaded by Pittosporum undulatum and numerous other weeds, while many other native species were significantly declining in abundance.

In areas of northern New South Wales that were previously used for plantation forestry of Eucalyptus grandis, but are now included in conservation estates, control of weeds in the understorey led to a significant increase in the density of the persistent species L. laterale (Cummings and Reid, 2008). Control of the invasive species bitou bush (Chrysanthemoides monilifera ssp. rotundata) in native bushland on coastal dunes in New South Wales led to an increase in cover of L. laterale though there were some short-term detrimental effects of herbicide spraying (Vranjic et al., 2011). Burrows and Wardell-Johnson (2003) suggest that L. squamatum (s.l.) disappears from long-unburnt tall karri (Eucalyptus diversicolor) forest, probably due to shading, although it may persist in the seed bank.

While some forms of disturbance are not overly detrimental, in the Buller District of New Zealand, grazing and trampling has resulted in the elimination of L. australe from dairy farms around the wetlands of the Kongahu Swamp (Sorrell and Partridge, 1999). Pelton and Conran (2002) found that vegetation rolling for firebreak construction in sandy heath communities in South Australia had a negative impact on two significant indicator species, L. carphoides and L. laterale.

While investigating energy content and flammability of common forest species in Tasmania, Dickinson and Kirkpatrick (1985) found that L. laterale had an energy content of around 20 000 J g⁻¹, an ash content (excluding silica) of 7–10 % and a silica content of 10 %, making them one of the least significant components of flammable material in the forest.

Germination and dormancy

Cyperaceae ‘seeds’ are technically a nutlet, the fruit comprising more than one carpel, but only a single seed, but as they are very small and one-seeded, they are sometimes referred to incorrectly as an achene (J. J. Bruhl, pers. comm.). Bruhl (1991) has confirmed that the thickened persistent scales at the base of the nutlet are in fact a perianth. Nutlet production is first dependent on inflorescence development. In Lepidosperma, the inflorescences are initiated during winter, with immature buds developing at this time, then undergoing a period of stasis over summer, maturing and flowering within weeks of breaking rains the following autumn (or occasionally after heavy summer rains) (R. L. Barrett, pers. observ.). This pattern is strong in the Western Australian species, but the timing is not as consistent in eastern Australian species (K. L. Wilson and J. J. Bruhl, pers. obs.). Lepidosperma spikelets are bisexual, with hermaphrodite flowers, most species developing several basal sterile bracts, followed by a functionally male flower and terminated by a bisexual flower (Bruhl et al., 1992; Bruhl, 1995; Goetghebeur, 1998). Spikelets are protogynous, the lower functionally male flower developing first, followed by the stigma of the bisexual flower, the stamens of the bisexual flower either developing later or remaining only partially developed (R. L. Barrett, pers. obs.). A few species such as L. jacksonense produce two bisexual flowers per spikelet (Barrett, 2007a). All species are considered to be wind-pollinated and population genetic studies suggest that they are primarily outcrossing (M. D. Barrett and M. Wallace, unpubl. data).

Potential nutlet production varies greatly between species of Lepidosperma, from 1–4 spikelets per inflorescence in L. tortuosum to over 1000 spikelets per inflorescence in L. elatius (Wheeler and Bruhl, 2000; R. L. Barrett, pers. obs.). Almost all species produce a single nutlet per spikelet; however, a few species have been observed to consistently produce two nutlets per spikelet (e.g. L. jacksonense, Barrett, 2007a). In Lepidosperma species, nutlets develop to approximately full size in a matter of weeks following fertilization (R. L. Barrett, pers obs.). These nutlets do not necessarily develop fully, with Wheeler and Bruhl (2000) finding that many nutlets appeared ‘full’ but were in fact lacking a developed embryo, a condition sometimes indicated by wrinkling of the nutlet surface (more prominent with age). Consistent winter rainfall is required to allow embryo fill, so with inflorescence development, two good seasons of rainfall are required for good nutlet development (R. L. Barrett, pers. obs.). This can be a rare combination in arid areas at the edge of the distribution of the genus (R. L. Barrett, pers. obs.).

Embryos were found to be small, only 0·12 mm long in L. clipeicola and only 0·40 mm long in L. elatius and L. laterale, and matched the Schoenus-type embryo morphology (Wheeler and Bruhl, 2000). Vanhecke (1974) studied the embryos of L. chinense, L. laterale (s.l.), L. longitudinale and L. sieberi (as L. squamatum) and found a similar size variation, from 0·20 to 0·32 mm long. The embryos are described as being asymmetric, with well-developed, S-shaped vascular tissue and with the germinal pore towards the base and to the side (Vanhecke, 1974). Of the four species currently held in the Millennium Seed Bank, seed weight (per thousand) ranges from 3·38 g for L. laterale to 7·05 g for L. urophorum (Royal Botanic Gardens Kew, 2008). These relatively small nutlets are more likely to be removed by ants (Westoby et al., 1990).

Only those nutlets naturally released from the inflorescence were considered developed by Wheeler and Bruhl (2000), an observation generally supported by Kodym et al. (2010). Pollen viability was very high (90–95 %) while nutlet viability was very low for L. clipeicola (0·5 %), and higher for L. elatius (72 %) and L. laterale (62 %), although no fruits were germinable due to an inability to overcome dormancy mechanisms (Wheeler and Bruhl, 2000).

In most Lepidosperma species, nutlets do not readily germinate without specific dormancy-breaking methods (Bell et al., 1993; Kodym et al., 2010; Dixon, 2011). Kullmann (1981) recorded some germination for L. gladiatum in pot trials, with seedlings emerging between 53 and 72 d after sowing. Many broad studies of natural germination rates have found very low recruitment for Lepidosperma species, even in cases where they are common components of the ecosystem (Lunt, 1997; Wang, 1997; Pettit and Froend, 2001; Fisher et al., 2009). Roche et al. (1997) found low levels of nutlet viability and no germination of Lepidosperma species was achieved from smoke treatments or non-smoke controls. Penman et al. (2008) found a significant germination response to heat treatment and a marginally significant germination response to smoke treatment for L. laterale from near Eden in New South Wales. Enright et al. (1997) found an occasional germination response to smoke in L. laterale from the Grampians National Park, western Victoria. Wills and Read (2002) found a germination response to heat treatment for L. sieberi (as L. concavum) from Gippsland, Victoria. Ward et al. (1997) found no response to heat or smoke in nutlets of L. tenue (= L. leptostachyum) from un-mined jarrah forest. However, they noted that the nutlets were collected in summer and as most fertile nutlets fall in late spring, they may have been using infertile nutlets. Physical disturbance of the soil seed bank of L. gladiatum, a species of coastal sand dunes, has been observed to promote increased germination (K. W. Dixon, pers. comm.).

Nutlet removal and dispersal

Lepidosperma nutlets have persistent hypogynous scales at the base that act as an elaiosome for ant dispersal (Berg, 1975; Barton, 1994). Local dispersal is probably due to ants (which collect fallen nutlets) and birds (which take nutlets directly from the inflorescence), with long-distance dispersal most likely attributable to birds. Berg (1975) suggests that myrmechory is a very important component in the distribution of these species and in maintaining habitat diversity. The hypogynous scales at the base of the nutlets of L. australe can become quite spongy and Edgar (1970) and Thorsen et al. (2009) suggest that this aids dispersal of the nutlets by water (hydrochory).

ECOLOGICAL ASSOCIATIONS

The nature of ecological associations can vary greatly. This section of the review attempts to detail the current knowledge of ecological associations for the genus Lepidosperma. Most recorded associations are with larger animals that have been well studied (mammals and birds in particular), although there are also a significant number of associations with insects and fungi recorded in the literature. This review attempts to assess the relative importance of Lepidosperma species to all organisms that are recorded in association with them. Current research suggests that a significant number of Lepidosperma species are short-range endemics (with a total range of less than 100 km²) (e.g. Barrett et al., 2009). Where these species are hosts for species-specific taxa such as Elachistine moths (Kaila, 2011), these species will also be intrinsically rare and all the more vulnerable to climatic fluctuations and ecosystem disturbance.

Mammal associations

Twenty-six mammal species in Australia have been recorded making use of Lepidosperma species as detailed in Table 2 and references cited there. Two are recorded as making use of Lepidosperma tussocks as nest sites, including Gilbert's potoroo (Potorous gilbertii) and the western ringtail possum (Pseudocheirus occidentalis). Seven Lepidosperma species form part of the diet of five mammal species: swamp rat (Rattus lutreolus), western grey kangaroo (Macropus fuliginosus), common wombat (Vombatus ursinus), the endangered quokka (Setonix brachyurus) and the introduced common fox (Vulpes vulpes). The habitat or occurrence of 24 mammal species is specifically recorded as being associated with Lepidosperma species. These include a number of small mammals that depend on dense cover for shelter. The Lepidosperma plants probably also provide habitat for the prey of many species, although this has not been specifically documented.

Table 2.

Mammal species associated with Lepidosperma

Mammal species	Lepidosperma	Community type	Location	Part	Use	References
Gilbert's potoroo – Potorous gilbertii (CE)	L. spp.	Long-unburnt dense vegetation	Two Peoples Bay, Western Australia	–	Habitat, nesting	1, 2, 3
Gilbert's potoroo (CE) Quokka – Setonix brachyurus (V)	L. gladiatum	Fringing vegetation	Bald Island, southern Western Australia	–	Habitat, refuge	4
Long-nosed potoroo – Potorous tridactylus (V); Australian swamp rat – Rattus lutreolus	L. laterale	Sedgeland	SW Victoria	–	Habitat	5
Tasmanian bettong – Bettongia gaimardi subsp. cuniculus (E in Tasmania)	L. longitudinale	Sedgeland	Tasmania	–	Habitat	6
Eastern barred bandicoot – Perameles gunnii (V)	L. laterale	Open woodland	E Tasmania	–	Habitat	7
Eastern barred bandicoot (E)	Large L. spp.	Dense ground cover	S Victoria	–	Habitat	8
Pacific rat – Rattus exulans	L. australe		Stewart Island, New Zealand	–	Habitat	9
Australian swamp rat; bush rat – Rattus fuscipes	L. spp.	Sedgeland	New South Wales	–	Habitat	10
Australian swamp rat	L. filiforme, L. spp.	Sedgeland		Rhizomes	Food, habitat	11, 12
Broad-toothed rat –Mastacomys fuscus (NT)	L. spp.	Sedgeland	New South Wales, Victoria, Tasmania	–	Habitat	13
Smoky mouse – Pseudomys fumeus	L. filiforme	Sedgeland		–	Habitat	14
New Holland mouse – Psuedomys novaehollandiae (V)	L. sieberi (as L. concavum), L. filiforme		Tasmania		Habitat	14
New Holland mouse (V)	L. semiteres	Sedgeland	S Victoria	–	Habitat	15, 16, 17
White-footed dunnart – Sminthopsis leucopus (V in Victoria); swamp antechinus – Antechinus minimus subsp. maritimus (NT in Victoria); other mammals	L. filiforme, L. laterale, L. semiteres		Otway Ranges, Victoria		Habitat	18, 19, 20
Brown antechinus – Antechinus stuartii	L. urophorum	Dense understorey	SE New South Wales			21
Kangaroo Island dunnart – Sminthopsis aitkeni (E)	L. spp.	Dense understorey	Kangaroo Island, SA			22
Western grey kangaroo – Macropus fuliginosus	L. tenue (?= L. leptostachyum), L. angustatum (= L. sp. aff. squamatum)	Jarrah forest	Perup area, Western Australia	Culms, leaves	Food	23
Western grey kangaroo; red-necked wallaby – Macropus rufogriseus	L. carphoides		Grampians, Victoria		Habitat (minor)	24
Parma wallaby – Macropus parma (R in New South Wales)	L. limicola	Sedge swamps	Gibraltar Range National Park, New South Wales		Habitat (unusual)	25
Tammar wallaby – Macropus eugenii	L. spp.	Dense vegetation			Day shelter	26
Quokka (V)	L. effusum (? & L. persecans)	Wet forest	SW Western Australia		Protective habitat	27, 28
Quokka (V)	L. squamatum (s.l.) & L. tetraquetrum	Wet forest	SW Western Australia	Culms, leaves	Food	29
Common wombat – Vombatus ursinus	L. viscidum	Mallee, heath	Messent Conservation Park, South Australia	Culms, leaves	Food	30
Western ringtail possum – Pseudocheirus occidentalis (V)	L. spp.	Dense sedges	Western Australia	Tussocks	Nesting sites	31
Little pygmy possum – Cercartetus lepidus	L. sieberi (as. L. concavum)	Dense understorey	Tooms, E Tasmania		Habitat	32
Dibbler – Parantechinus apicalis (E)	L. gladiatum	Long-unburnt heath	WA Islands		Habitat	33
Leadbeater's possum – Gymnobelideus leadbeateri (E)	L. elatius	Sedge-rich Eucalyptus camphora swamp (E)	Victoria		Habitat association	34
Flute-nosed bat – Murino florium (R)	L. laterale	Open forest	N Queensland		Habitat association	35
European fox – Vulpes vulpes	L. gladiatum		Cape Woolamai, Victoria	Leaves	Food	36

Abbreviations: V, Vulnerable; E, Endangered; CE, Critically Endangered; NT, Near Threatened; R, Rare. These categories refer to current National listings under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act, Australia) unless otherwise specified. Geographical abbreviations: NZ, New Zealand; SA, South Australia; WA, Western Australia.

References: 1. Vetten, 1996. 2. Courtenay and Friend, 2004. 3. Friend, 2008. 4. Abbott, 1980. 5. Bennett, 1993. 6. Taylor, 1992. 7. Mallick et al., 1997. 8. Seebeck et al., 1990. 9. Harper et al., 2005. 10. Lunney, 2008. 11. Braithwaite et al., 1978. 12. Cockburn, 1981. 13. Wallis et al., 1982. 14. Lazenby et al., 2007. 15. Lock and Wilson, 1999. 16. Wilson and Bradtke, 1999. 17. Wilson and Laidlaw, 2003. 18. Wilson et al., 1990. 19. Wilson et al., 2001. 20. Wilson and Aberton, 2006. 21. Lorch et al., 2007. 22. Gates, 2009. 23. Shepherd et al., 1997. 24. Coulson, 1987. 25. Vernes and Cooper, 2007. 26. Hinds, 2008. 27. de Tores et al., 2007. 28. de Tores, 2008b. 29. Hayward, 2005. 30. Hume and Barboza, 1998. 31. de Tores, 2008a. 32. Duncan and Taylor, 2001. 33. Bencini et al., 2001. 34. Turner and Rylah, 2003. 35. Kutt and Schulz, 2000. 36. Norman, 1971.

Dense stands of Lepidosperma species can form stable habitats that are important to the long-term survival of a number of rare and threatened mammal species. Lepidosperma species provide habitat for the critically endangered Gilbert's potoroo and endangered quokka (along with a number of Australia's rarest birds; see below). Both species are found in dense vegetation cover in long-unburnt areas where along with the dominant rush Anarthria scabra, Lepidosperma species form an important component of the understorey (Vetten, 1996; Courtenay and Friend, 2004). The potoroo's nesting sites are usually under a dense cover of sedges (Friend, 2008). This species was considered extinct for around 100 years before being rediscovered near Two Peoples Bay on the southern coast of Western Australia (Sinclair et al., 1996). Bald Island is a small Western Australian island with a large amount of fringing vegetation dominated by L. gladiatum (Abbott, 1980), a species that provides refugial habitat for the Gilbert's potoroo and quokka. Lepidosperma species, which dominate sedgelands or the understorey of woodlands, form a major habitat for a number of rare species including the Tasmanian bettong (Bettongia gaimardi cuniculus), a species now extinct on the mainland (Taylor, 1992), the eastern barred bandicoot (Perameles gunnii), New Holland mouse (Pseudomys novaehollandiae), Kangaroo Island dunnart (Sminthopsis aitkeni), white-footed dunnart (Sminthopsis leucopus) and the swamp antechinus (Antechinus minimus subsp. maritimus) (Table 2).

Within habitats dominated by sedges, further segregation of mammal species can be found. The swamp rat (Rattus lutreolus) and bush rat (Rattus fuscipes) are both found in sedgeland in New South Wales that includes Lepidosperma species. However, the behaviour of the swamp rat effectively excludes the bush rat from the wetter sedgeland habitats (low, open vegetation dominated by Cyperaceae and Restionaceae) dominated by different Lepidosperma species (Lunney, 2008). The swamp rat is the only species recorded eating the rhizomes of a Lepidosperma species (L. filiforme) providing the marsupial rat with an important food resource (Braithwaite et al., 1978; Cockburn, 1981). Evergreen sedges can be an important dietary component for animals such as the western grey kangaroo, particularly once annual plant species have senesced (Shepherd et al., 1997). Under drought conditions, the rare species L. rupestre is heavily grazed by kangaroos in the Kalbarri Gorge, Murchison River (R. L. Barrett, R. D. Phillips and A. Faber, pers. obs.).

The western ringtail possum is usually found in areas with good coverage of Lepidosperma species in the understorey and may nest on the ground where these sedges are particularly dense (de Tores, 2008a). The endangered dibbler (Parantechinus apicalis) survives in long-unburnt heath communities where it is not especially habitat-specific, but does inhabit L. gladiatum thickets on islands in Western Australia (Bencini et al., 2001). The flute-nosed bat (Murino florium), a rare species from northern Queensland, is occasionally found in habitats with an understorey containing L. laterale (s.l.) (Kutt and Schulz, 2000). It is unlikely that this plant species is of any particular importance to the bat in these locations, but it is possible that the sedge provides habitat for insects on which the bat feeds. It is interesting that the introduced fox (Vulpes vulpes) has been recorded as regularly consuming the leaves of L. gladiatum on Cape Woolamai, Victoria (Norman, 1971).

Bird associations

Forty-three bird species in Australia and New Zealand have been noted making use of Lepidosperma species (Table 3, and references cited there). Thirteen are recorded as making use of Lepidosperma tussocks as nest sites. These records include the little penguin (Eudyptula minor) and short-tailed shearwater (Puffinus tenuirostris), with L. gladiatum in Western Australia and L. laterale in Tasmania providing protective cover and stability for sandy burrow substrates. Eleven bird species noted as nesting among Lepidosperma species are mainly found in coastal thickets and dense forest understorey vegetation. These birds include the endangered western whipbird (Psophodes nigrogularis leucogaster and nigrogularis), Mt Lofty Ranges subspecies of the southern emu-wren (Stipiturus malachurus intermedius), rufous bristlebird (Dasyornis broadbenti) and the vulnerable noisy scrub-bird (Atrichornis clamosus, Fig. 5). The actual Lepidosperma species involved is not specified in most records, although pilotbirds (Pycnoptilus floccosus) are recorded as nesting in L. elatius and noisy scrub-birds in L. sp. Manypeaks Large (R. L. Barrett RLB 2476) (recorded as L. longitudinale or L. persecans). Four of the birds nesting in Lepidosperma species have also been noted to incorporate Lepidosperma leaf material in their nest construction (the rufous bristlebird, pilotbird, noisy scrub-bird and western whipbird). The noisy scrub-bird is known to utilize L. effusum, L. gladiatum, L. sp. Manypeaks Large (R. L. Barrett RLB 2476) and the unusual L. tetraquetrum, which has rigid, four-angled culms that are flattened for nest construction (S. Comer, pers. comm.).

Table 3.

Bird species associated with Lepidosperma

Bird species	Lepidosperma	Community type	Location	Part	Use	References
Emu – Dromaius novaehollandiae	L. carphoides	Heath	Victoria	Fruit	Food	1, 2, 3
Burrow-nesting seabirds – penguins, shearwaters, petrels and gulls	L. gladiatum	Islands, coastal dunes	Michaelmas Is., Western Australia	Sward	Nest habitat stability / cover	4
Short-tailed shearwater – Puffinus tenuirostris; Little penguin – Eudyptula minor	L. laterale	Coastal dunes	Cape Queen Elizabeth, Tasmania	–	Nest habitat stability/cover	5
Australasian bittern – Botaurus poiciloptilus (E)	L. effusum	Lake edges	Lake Muir, Western Australia	–	Habitat	6
White-throated treecreeper – Cormobates leucophaea; superb fairy-wren – Malurus cyaneus; grey shrike-thrush – Colluricincla harmonica; grey fantail – Rhipidura fuliginosa	L. laterale	Vegetation community boundaries	Southern Victoria	–	Habitat	7
Red-browed finch – Neochmia temporalis	L. carphoides L. tetraquetrum	Creeklines, heath	SW Western Australia	Fruit	Food	8, 9, 10, 11, 12
Beautiful firetail – Stagonopleura bella; red-eared firetail – Stagonopleura oculata	L. angustatum, L. gladiatum, L. persecans	Forest, coastal vegetation	SW Western Australia	Fruit	Food	9, 13, 14, 15, 16
Red-eared firetail	L. angustatum	Coastal vegetation	Southern Western Australia	Fruit	Habitat, food	17, 18
Western bristlebird – Dasyornis longirostris (E)	Large L. spp.		Southern Western Australia	–	Habitat	15, 19, 20, 21, 22
Eastern bristlebird – Dasyornis brachypterus (E)	L. forsythii	Unburnt habitats		–	Habitat	23
Rufous bristlebird – Dasyornis broadbenti (E)	L. [elatius], L. laterale, L. gladiatum L. sp.	Coastal areas	Victoria	Swards Leaves	Habitat, nest material	22, 24, 25, 26
Pilotbird – Pycnoptilus floccosus	L. elatius	Wet forests	Southern Victoria	Tussocks,leaves	Preferred habitat, nest site/material	27, 28, 29, 30
Ground parrot – Pezoporus wallicus	L. sp.	Heath	SE Australia	Fruit	Food	31, 32
Ground parrot	L. filiforme	Heath	Tasmania	Fruit	Food	33, 34
Western ground parrot – Pezoporus flaviventris (E)	Unnamed sp. (as L. brunonianum)	Heath	Western Australia	Fruit	Food	35, 36
Crimson rosella – Platycercus elegans	L. laterale L. spp.	Various Gardens	SE Australia	Fruit	Food	34, 37, 38
Eastern rosella – Platycercus eximius	L. laterale		SE Australia	Fruit	Food	34, 39
Orange-bellied parrot – Neophema chrysogaster (juveniles) (CE)	L. filiforme		SE Australia	Fruit	Food	34, 40
Orange-bellied parrot (CE)	L. spp. L. gladiatum	L. sedgelands	South Australia	Fruit	Habitat, food	41
Turquoise parrot – Neophema pulchella	L. laterale		SE Australia	Fruit	Food	34, 42
Kakapo – Strigops habroptilus (E in New Zealand)	L. australe		Codfish, Stewart Is., New Zealand	Culms	Food	43
Noisy scrub-bird – Atrichornis clamosus (V)	L. sp. Manypeaks Large (R. L. Barrett RLB 2476) (as L. longitudinale or L. persecans); L. effusum, L. gladiatum, L. tetraquetrum	Dense shrubland, wet gullies	East of Albany, Western Australia	Tussocks, leaves	Nest site and material	15, 44, 45, 46, 47, 48, 49, S. Comer, pers. comm.
Western whipbird – Psophodes nigrogularis subsp. leucogaster & subsp. nigrogularis (V)	L. spp.			Tussocks	Nest site, nest material	50, 51, 52, 53
Superb fairy-wren – Malurus cyaneus; splendid fairy-wren – M. splendens; southern emu-wren – Stipiturus malachurus		Swamp margins		–	Habitat	49
Superb fairy-wren	Large species			Tussocks	Nest site	54, 55
Variegated fairy-wren – Malurus lamberti	L. spp.	Wet gullies			Habitat	56
Blue-breasted fairy-wren – Malurus pulcherrimus	L. sp.		Western Australia	Tussocks	Nest site	57
Red-winged fairy-wren – Malurus elegans	L. effusum, L. longitudinal, L. persecans, ?L. tetraquetrum	Dense L. spp. stands, stream & swamp margins	SW Western Australia		Habitat	49, 58, 59
White-winged fairy-wren – Malurus leucopterus	L. sp; probably L. gladiatum	Coastal heath	SW Western Australia		Occasional habitat	49
Mt Lofty Ranges southern emu-wren – Stipiturus malachurus subsp. intermedius (E)	L. longitudinale	Open wet forest	South Australia	Fruit, tussocks	Food, nest site	60, 61
Eyre Peninsula southern emu-wren – Stipiturus malachurus subsp. parimeda (V)	L. viscidum	Low woodland, mallee	South Australia		Habitat	62
Striated fieldwren – Calamanthus fuliginosus	L. spp.	Regrowth understorey		Tussocks	Occasional nesting	63
Striated thornbill – Acanthiza lineata; jacky winter – Microeca fascinans; crested shrike-tit – Falcunculus frontatus; rufous whistler – Pachycephala rufiventris		Forests	Bega, New South Wales		Habitat	64
Spotted quail-thrush – Cinclosoma punctatum subsp. anachoreta (CE)	L. semiteres	Open eucalypt woodland			Habitat	65
Helmeted honeyeater – Lichenostomus melanops subsp. cassidix (E); Lewin's rail – Rallus pectoralis (E); spotless crake – Porzana tabuensis; southern emu-wren	L. laterale L. spp.	Sedge-rich Eucalyptus camphora swamp	Victoria		Co-occurrence, nesting habitat	66, 67
Yellow-throated honeyeater – Lichenstomus flavicollis	L. sp.		N Tasmania	Tussocks, leaves	Nest site, nest material	68, 69
Spotted pardalote – Pardalotus punctatus	L. spp.				Habitat	64, 70

Abbreviations: V, Vulnerable; E, Endangered; CE, Critically Endangered. These categories refer to current National listings under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act, Australia) unless otherwise specified.

References: 1. Quin, 1984. 2. Marchant and Higgins, 1990. 3. Davies, 2002. 4. Abbott, 1981. 5. Walsh et al., 1997. 6. Lane et al., 1996. 7. Berry, 2001. 8. Immelmann, 1962. 9. Immelmann, 1967. 10. Dell, 1965. 11. Read, 1987. 12. Read, 1994. 13. Immelmann, 1960. 14. Pepper, 1964. 15. Johnstone and Storr, 2004. 16. Higgins et al., 2006. 17. Nichols et al., 1982. 18. Bamford, 1989. 19. Smith and Moore, 1977. 20. McNee, 1986. 21. Smith, 1987. 22. Higgins and Peter, 2002. 24. Campbell, 1906. 25. Du Guesclin et al., 1995. 26. Peter, 1999. 23. Baker, 2000. 27. Anon., 1908. 28. Howe, 1915. 29. Zwart, 1973. 30. Smith, 1984. 31. Meredith et al., 1984; 32. Forshaw, 2002. 33. Bryant, 1994, 34. Higgins, 1999. 35. Barth, 2007. 36. Murphy et al., 2011. 37. Lepschi, 1993. 38. Knight, 2000. 39. Rose, 1997. 40. Brown and Wilson, 1984. 41. Clarke, 2004. 42. Quin, 1990. 43. Wilson, 2004. 44. Webster, 1963. 45. Smith and Robinson, 1976. 46. Smith, 1985. 47. Danks et al., 1996. 48. Smith, 1996. 49. Higgins et al., 2001. 50. Howe and Ross, 1933. 51. Bryant, 1938. 52. Woinarski et al., 1988. 53. Smith, 1991. 54. Dove, 1910a. 55. Dove, 1910b. 56. Schodde, 1996. 57. Brooker and Brooker, 2001. 58. Payne et al., 1991. 59. Rowley et al., 1988. 60. Littlely and Cutten, 1994. 61. Westphal et al., 2003. 62. Pickett, 2002. 63. Dove, 1912. 64. Smith, 1984. 65. Garnett and Crowley, 2000. 66. Pearce and Minchin, 2001. 67. Turner and Rylah, 2003. 68. Dove, 1915. 69. Dove, 1917. 70. Higgins and Peter, 2002.

Fig. 5.

Nest of the vulnerable noisy scrub-bird (Atrichornis clamosus) built in, and with leaves of, the rare sedge Lepidosperma sp. Manypeaks Large (R. L. Barrett RLB 2476), Manypeaks Range, Western Australia. (A) Female on ‘runway’ of nest (photo: Graeme Chapman). (B) Nest made primarily from sedge leaves (photo: Sarah Comer).

Ten Lepidosperma species form part of the diet of 12 bird species: emu (Dromaius novaehollandiae), southern emu wren (Stipiturus malachurus), three finch/firetail species and seven parrots, including the endangered New Zealand kakapo (Strigops habroptilus). The record of emus eating the nutlets of L. carphoides is particularly interesting, as emus are noted long-distance dispersers of plant species (e.g. Calviño-Cancela et al., 2006; He et al., 2008). The habitat or occurrence of a further 17 bird species is specifically recorded as associated with Lepidosperma species; these include many small forest understorey insectivores, including the grey fantail (Rhipidura fuliginosa) and four fairy wren species (Malurus spp.) as well as endangered ground-layer birds such as the spotted quail-thrush (Cinclosoma punctatum anachoreta) and western bristlebird (Dasyornis longirostris). It is also of interest that there are no records of a number of gramnivorous birds such as doves and pigeons feeding on Lepidosperma fruit, but this may be due to a lack of precise observations at the right time of year rather than an absence of utilization.

Reptile associations

Lepidosperma clipeicola is an important habitat plant for an arboreal snake, Stephens' banded snake (Hoplocephalus stephensii). This snake spends a great deal of its foraging time in the culms of L. clipeicola (Fitzgerald et al., 2002a, b). Prey species of this threatened snake are regularly caught while among dense stands of L. clipeicola culms and maintenance of healthy populations of this sedge are important for the long-term survival of the snake (Fitzgerald et al., 2004).

The federally endangered Blue Mountains water skink (Eulamprus leuraensis) inhabits swamps dominated by sedges including L. limicola, and protection of these habitats is critical for the long-term survival of the skink (Keith and Benson, 1988; LeBreton, 1996; NPWS, 2001). Along with the helmeted honeyeater (Lichenostomus melanops subsp. cassidix), the vulnerable swamp skink (Egernia coventryi) is found in a sedge-rich Eucalyptus camphora swamp with L. laterale, a habitat that is listed as endangered in Victoria (Turner and Rylah, 2003). Three skink species are found in Eucalyptus regnans forest with an understorey including L. elatius: the southern forest cool-skink (Niveoscincus coventryi), the southern water skink (Eulamprus tympanum) and the trunk-climbing cool-skink (Pseudemoia spenceri) (Brown and Nelson, 1993). Reptile ecology is poorly understood in these forest ecosystems and habitat complexity is considered critical to maintaining animal diversity (Lindenmayer, 2009). Michael et al. (2010) have shown that many reptile species occurring on granite outcrops require specific rock structures and specific vegetation structures to maintain viable populations and this needs to be considered in the management of granite outcrops where Lepidosperma species are often prominent.

Amphibian associations

Lepidosperma concavum has been recorded as potential breeding habitat for the vulnerable green and golden bell frog (Litoria aurea) on Bowen Island in New South Wales (Osborne and McElhinney, 1996). The rare Nornalup frog (Geocrinia lutea) and Karri frog (G. rosea) can be found calling from stands of L. effusum and L. tetraquetrum (Wardell-Johnson and Roberts, 1993). Lea's frog (Geocrinia leai) often lays its eggs in sedges overhanging wetlands and waterways (Pen, 1999). The slender tree frog (Litoria adelaidensis) requires dense vegetation including sedges fringing waterways for protective habitat (Pen, 1999).

Insect associations

The presence or absence of butterflies and moths with species- or genus-specific plant associations can be useful indicators in ecological restoration projects (Lomov et al., 2006). The three-spot skipper butterfly (Motasingha trimaculata) is dependent on Lepidosperma and Phlebocarya (Haemodoraceae) species as larval food plants and female adults remain close to these food plants (Symon, 1980; Braby, 2000; Sands and New, 2002).

The moth genus Elachista has a number of species with larvae dependent on Lepidosperma species and Kaila and Ståhls (2006) indicated the possibility of species-specific inter-relationships with further studies of their taxonomy required. Kaila (2011) has now shown that there are indeed a large number of species-specific relationships between Elachista and Lepidosperma. At least 34 Elachista species depend on Lepidosperma species for their larval stage, forming distinctive mines in leaves (Fig. 6; Table 4). For many more species, the host plant remains unknown. Multiple Elachista species may utilize a single species of Lepidosperma by occupying different parts of the same leaf; however, in most cases, Elachista species are restricted to a single host species (Kaila, 2011). Due to the lack of taxonomic knowledge in the genus Lepidosperma and a lack of current identification tools, many of the host Lepidosperma species could not be fully identified by Kaila (2011) and a summary of the current taxonomy as far as can be interpreted is presented in Table 4. There are numerous moth species in tussock grasslands of New Zealand (including Elachista species) that have larval associations with Cyperaceae species, but the genera of Cyperaceae involved were usually not recorded, so the utilization of Lepidosperma species remains uncertain (White, 2002).

Fig. 6.

Elachistine moths associated with Lepidosperma species. (A) Elachista tetraquetri (host = L. tetraquetrum); (B) Elachista flavicilia (host = L. effusum); (C) mines of Elachista gladiograpta on L. gladiatum; (D) (1) mines of Elachista gladiatrix on L. gladiatum; (2) Elachista gladiograpta on L. gladiatum; and (3) Elachista spongicola on Machaerina arthrophylla (photos: Lauri Kaila). Scale bars: A, B = 2 mm.

Table 4.

Updated nomenclature for Lepidosperma species with dependent species of Elachista (Kaila, 2011).

Elachista species	Host Lepidosperma	Revised identification
E. bidens	L. tuberculatum	No change
E. carcharota	L. concavum and possibly also L. congestum	L. sieberi and L. ?congestum
E. catagma	L. gladiatum	No change
E. chilotera	L. tuberculatum	No change
E. crenatella	L. viscidum	No change
E. cylistica	L. sp.	Probably L. leptostachyum, but may be L. asperatum, L. pubisquameum or L. sp. Darling Range Heath (K.L. Wilson 8926)
E. cynopa	L. laterale	This name currently includes several taxa
E. deusta	L. ?elatius	L. effusum
E. effusi	L. gladiatum and L. effusum	L. gladiatum and probably L. persecans
E. epartica	L. concavum and L. viscidum	L. ?latens and L. aff. concavum
E. eriodes	L. sp. (concavum/congestum)	L. sp. ?several choices in this area
E. etorella	L. gladiatum, L. effusum + various Lepidosperma	L. gladiatum, L. ?persecans, L. sp. Coastal Dunes (R.J. Cranfield, 9963), L. sp. Sand Dunes (R. L. Barrett et al. RLB 5034)
E. faberella	L. longitudinale	Eastern form
E. flavicilia	L. ?elatius	L. effusum
E. floccella	L. laterale	2 species
E. gladiatrix	L. gladiatum	No change
E. gladiograpta	L. gladiatum	No change
E. illota	Two unidentified relatively small Lepidosperma species	L. sp. Sand Dunes (R. L. Barrett et al. RLB 5034) and L. sp.
E. lachnella	L. longitudinale	Eastern form
E. magidina	L. laterale and L. elatius	No change (s.l.)
E. melanthes	L. semiteres	No change
E. ophelma	L. gladiatum	No change
E. paragauda	L. concavum and L. laterale	May be L. concavum or L. sieberi.
E. paryphoea	L. curtisiae and L. sp. nr. laterale	Probably both are L. spp. nov.
E. platysma	L. tuberculatum	No change, plus L. sp. Jerdacuttup, L. sp.
E. ruscella	Several spp.	L. sp. Coastal Dunes (R.J. Cranfield, 9963) L. sp. Sand Dunes (R. L. Barrett et al. RLB 5034) and L. sp.
E. spathacea	L. longitudinale	Western form
E. species A, E. melanthes complex	L. longitudinale	Western form
E. spongicola	Presumably a Lepidosperma species	Probably Schoenoplectus validus
E. stictifica	L. sp.	L. effusum
E. tetraquetri	L. tetraquetrum	No change
E. toralis	L. concavum and L. viscidum	Probably = L. sieberi and L. concavum
E. toryna	L. longitudinale	Eastern ?and Western forms
E. velutina	L. longitudinale and ?L. limicola	Eastern form

The magnificent sunmoth (Synemon magnifica) relies on L. viscidum/L.concavum (and possibly L. laterale) as a larval food plant with the larvae feeding on the rhizomes of the plant (Common and Edwards, 1981; Common, 1990; Zborowski and Edwards, 2007). The white-banded sunmoth (Synemon directa) is thought to breed on L. gladiatum (M. Williams, pers. comm.; ABRS, 2009). Larvae of the endangered graceful sunmoth Synemon gratiosa from the Perth region primarily feed on Lomandra, but is also reported to feed on Lepidosperma species (Burbidge, 2004). Larvae of several other Synemon species are also known to feed on Lepidosperma species in Western Australia, but the exact species associations are yet to be determined (T. Edwards, pers. comm.). Larvae of Synemon parthenoides are known to feed on L. carphoides in South Australia and Victoria (Douglas, 2008). A newly recognized Synemon species, the Kangaroo Island sunmoth, restricted to Kangaroo Island, feeds on L. viscidum (Grund, 2011; A. Young pers. comm.; Fig. 7).

Fig. 7.

The rare Kangaroo Island sun moth (Synemon sp.) on Lepidosperma viscidum, Kangaroo Island, South Australia. The larval casing can be seen in the bottom right of the image (photo: Andrew Young).

Larvae of several species of Miscera also feed on the rhizomes of Lepidosperma species, including M. desmotoma and two undescribed species in Victoria and M. centropis in Western Australia (Kallies, 2004; Zborowski and Edwards, 2007; T. Edwards, pers. comm.; A. Kallies, pers. comm.). Larvae of a Miscera species have been observed feeding on the roots of the rare species L. gibsonii when grown in pots in a glasshouse in Perth, but the origin of the moths is uncertain (B. Miller, pers. comm.). The sedge moth Glyphipterix gemmipunctella also feeds on several Lepidosperma species in eastern Australia (A. Kallies, pers. comm.).

While morabine grasshoppers are polyphagous, studies by Blackith and Blackith (1966) suggest that L. gladiatum, a species naturally occurring in their habitat, is specifically avoided. Predation of Lepidosperma culms and leaves by insects has only been observed on rare occasions (R. L. Barrett, pers. obs.) and there may be some form of defence such as the flavonols identified by Harborne et al. (1985). The high silica concentration in the leaves and culms may also be an effective deterrent (Norton, 1967). Six grasshopper species are known to feed on Lepidosperma species, Propsednura peninsularis apparently feeding only on L. laterale (Rentz et al., 2003; Table 5).

Table 5.

Grasshoppers known to feed on Lepidosperma species (Rentz et al., 2003, and references therein)

Grasshopper species	Lepidosperma food species
Western coastal pyrgomorph – Monistria latevittata	L. gladiatum
Western flag-face – Propsednura eyrei	L. tuberculatum
Eastern flag-face – Propsednura peninsularis	L. laterale
Variable psedna – Psedna nana	L. sp. [probably L. longitudinale]
Common psedna – Psedna pedestris	L. longitudinale
Musgrave's psedna – Psedna musgravei	L. spp.

The katydid Chlorodectes loquax is associated with a Lepidosperma sp. in coastal New South Wales (possibly L. concavum) (Rentz, 1985). Seven of the 11 species of the katydid genus Kawanaphila (K. gidya, K. goolwa, K. iyouta, K. mirla, K. nartee, K. ungarunya and K. yarraga) are usually found in association with a variety of Lepidosperma species (including L. carphoides and L. tenue). The Lepidosperma species provide a protective habitat during the day with the katydids feeding on the pollen of a variety of plant species by night (Rentz, 1993, 2010). Kawanaphila species are possible dispersal agents for pollen due to hairs on their bodies effectively holding pollen (Rentz, 1993).

Many plant species have seeds that are distributed by ants. The activity of ants in native vegetation is very important and can be a key factor in the success of ecosystem function of restored communities (Grimbacher and Hughes, 2002). Berg (1975) appears to have been the first to observe myrmechory in Lepidosperma, after recording a decorator ant [Monomorium (Chelaner) sp. cf. rothsteini] collecting the nutlets of a Lepidosperma species. Siddiqi et al. (1976) recorded ants dispersing the nutlets of L. laterale. Drake (1981) found that the ant Aphaenogaster longiceps collected significant numbers of L. laterale nutlets on North Stradbroke Island, Queensland, and noted the hypogynous scales to function as an elaiosome type. Rice and Westoby (1981) found that L. elatius is a myrmecochore and suggested that L. filiforme, L. flexuosum, L. laterale, L. lineare, L. urophorum and L. viscidum (= L. concavum) may also be myrmecochores. Ants from the genera Iridomyrmex and Phedole were observed to remove seeds of L. laterale in cafeteria experiments conducted in natural habitats on Bribie Island, south-eastern Queensland (Barton, 1994). French and Westoby (1996) recorded myrmecochory in L. flexuosum, L. laterale and L. urophorum in fire-prone sites in the Sydney region. Barton (1994) determined the presence of lipids in the hypogynous scales, confirming their role as an elaiosome.

In December 2009, in the Bald Knob State Forest, northern New South Wales, the author observed that ants (an Iridomyrmex sp.) rapidly collected ten nutlets of L. laterale (s.l.) that were picked ripe from the plant and dropped on bare ground in the vicinity of an ant nest. The whole nut was collected (the ants gripping the relatively large nutlets by the hypogynous scales) and taken into the nest (Fig. 8). No discarded nutlets or hypogynous scales were observed around the entrance to the nest.

Fig. 8.

Iridomyrmex sp. collecting mature nutlets of Lepidosperma laterale (s.l.) in the Bald Knob State Forest, northern New South Wales. Nutlets were gripped by the white hypogynous scales, an elaiosome type recognized by Berg (1975).

A number of ants (Chelaner, Iridomyrmex, Myrmecorhynchus, Prolasius, Solenopsis and Strumigenys species) are most common in tall open forests, often with L. elatius dominant in the understorey in sites at Wilsons Promontory in Victoria (Andersen, 1986). The golden spiny ant (Polyrhachis ammon) regularly builds its nests in tussocks of L. laterale in woodland in New South Wales (Gibb and Hochuli, 2003). Other unidentified ants have been observed preferentially nesting in Lepidosperma tussocks in Western Australia (R. L. Barrett, pers. obs.).

While there are some records of native bees collecting pollen (Houston, 2000), Lepidosperma species are all considered to be wind pollinated, as are most Cyperaceae (Goetghebeur, 1998). There are some exceptions (Friedman, 2011), and more observations would be beneficial as it is likely that bees collecting pollen do occasionally cause pollination. The implications of wind pollination for speciation in monocotyledons have been widely discussed (see Barrett et al., 2000; Friedman and Barrett, 2009a, b; and references therein).

Three native bee species have been recorded collecting pollen from L. ?gladiatum: Amegilla pulchra (Apidae), Megachile macularis (Megachilidae) and Stenotritus sp. SM7 (Stenotritidae) (Houston, 2000). Given that the majority of Lepidosperma species rapidly flower en masse following season-breaking rains in late autumn in south-west Western Australia and in the Mediterranean climate parts of South Australia and south-west Victoria, at a time when relatively few native plants are flowering, this may well be a critical source of pollen for these and other bee species at this time of year. As Lepidosperma flowers are protogynous, these pollen-collecting bees are unlikely to cause pollination of Lepidosperma species. The introduced European Honey Bee (Apis mellifera, Apidae) has also been noted to collect pollen from Lepidosperma species (Paton, 1996) and collection of pollen of L. gladiatum has been observed in Perth suburbs (M. Wallace, pers. comm.).

The collembola species Xenylla cf. obscura has been found living in Lepidosperma tussocks in South Australia (da Gama, 1979). A scale insect Paraonidiella cladii (as Chrysomphalus) is known to feed on Lepidosperma species (Fernald, 1903). Other scale insects have been observed, but not formally identified (Fig. 9). Slater (1975, 1976) recorded L. squamatum (s.l.) (as L. angustatum) as a host plant for both nymphs and adults of the sap-sucking bug Ontiscus obscurus (Lygaeidae), which feeds on the nutlets of this species.

Fig. 9.

Scale insect on the rare Kalbarri sword sedge (Lepidosperma rupestre), Kalbarri Gorge, Western Australia.

Snail associations

Regan et al. (2001) and Taylor et al. (2003) have recorded L. elatius as a component of the habitat of a rare land snail (Tasmaphena lamproides) in north-eastern Tasmania. The introduced common garden snail (Helix aspersa) is commonly found on L. gladiatum on the Swan Coastal Plain in Western Australia (R. L. Barrett, pers. obs.).

Arachnid associations

While sampling Lepidosperma specimens, a large number of unidentified spider species have been found foraging, or building webs in the tussock bases (R. L. Barrett, pers. obs.). One is most likely from the ground-dwelling spider genus Miturga (Miturgidae) which commonly builds silken retreats in protected sites such as in sedge tussocks or at the base of shrubs (M. Rix, pers. comm.; Fig. 10). Lepidosperma australe is a habitat species for the rare red katipo spider (Latrodectus katipo) in New Zealand (Patrick, 2002). In Western Australia, five short-range endemic spiders, the synotaxid Calcarsynotaxus benrobertsi, the archaeids (assassin spiders) Zephyrarchaea barrettae, Z. melindae and Z. robinsi and the malkarid Perissopmeros darwini, are all found under or near the shaded leaves of Lepidosperma species (mainly L. sp. Bluff Knoll Robust (G.J. Keighery 12595) and possibly L. persecans; Rix et al., 2009; Rix and Harvey, 2012a; S. Barrett, pers. comm.). These spider species are only known from a few peaks and gullies in the Stirling Range National Park (Rix et al., 2009; Rix and Harvey, 2012b). Similarly, Main's assassin spider Zephyrarchaea mainae is restricted to litter lodged in the crown of Restionaceae species, L. gladiatum and L. effusum, which grow under long-unburnt stands of weeping peppermint (Agonis flexuosa (Willd.) Sweet; Rix and Harvey, 2009, 2012a). This habitat also supports a range of smaller spiders on which the assassin spiders feed (Rix and Harvey, 2009). Assassin spiders represent a relictual lineage with similar fossil relatives dating back to the Jurassic (150 Mya) (Platnick, 1991; Rix and Harvey, 2012a, b).

Fig. 10.

Silken retreat from a juvenile ground-dwelling spider in the genus Miturga (Miturgidae) built in the base of a large Lepidosperma tussock, Mount Lesueur, Western Australia.

Freshwater organisms

Freshwater pools in creeks and rivers provide habitat for a wide range of organisms. In summer months, numerous animals, including fish, lampreys and freshwater crayfish, require shade provided by fringing vegetation during the day. Sedges such as Lepidosperma play an important role in many riparian areas (Pen, 1999). Three species of freshwater crayfish, the Dunsborough burrowing crayfish (Engaewa reducta), the Margaret River burrowing crayfish (Engaewa pseudoreducta) and the Walpole burrowing crayfish (Engaewa walpolea), are found in southern Western Australia and all are considered to be federally endangered (Department of Environment and Conservation, 2008). These species occur in small swamps and creeklines that are dominated by dense vegetation (including several Lepidosperma species) that provides cover for their fragile burrows in the banks of pools (Burnham et al., 2007). In north-eastern Tasmania, the endangered Scottsdale burrowing crayfish (Engaeus spinicaudatus) is found in creek and swamp habitats where L. elatius is a common part of the vegetation cover and L. filiforme is also occasionally present (Wapstra et al., 2006). Traylor et al. (1996) have identified 192 aquatic invertebrate, fish and amphibian species in south-western Australian ecosystems, many of which are likely to be reliant on the condition and species composition of wetland vegetation where Lepidosperma species are often prominent. Specific associations with wetland vegetation patterns and individual plant species are yet to be studied for the majority of these animal species.

Macroinvertebrates

Dense riparian vegetation, including L. tetraquetrum, which can form monospecific stands along creeklines, is highly beneficial to the health of macroinvertebrate communities in these ecosystems (Armstrong et al., 2005).

Microbial activity

The combination of living stands and dead litter of L. longitudinale supports microbial activity, which captures excess phosphorus from agricultural systems and incorporates it into the wetland sediments (Chambers, 1988; Chambers et al., 1993). Sedge communities bounding wetlands, waterways and estuaries act as an important nutrient trap (Pen, 1999; Brearley, 2005). Lepidosperma longitudinale often dominates wetlands with impeded drainage (Benson, 1981; Brearley, 2005). While little is known of specificity (or even taxonomy), amoebae have been found associated with the rhizosphere of L. semiteres (Foster, 1988).

Fungal associations

While smuts are considered detrimental to the host plant, reducing seed production through infection of the inflorescence, Savile (1979) and Lutz et al. (2012) have highlighted the value of rust and smut fungi in providing an independent assessment of evolutionary trends in the Cyperaceae. Two smut species were described from Lepidosperma species by McAlpine (1910) as Tolyposporium lepidospermae and T. rodwayi, both now included in Moreaua. Websdane et al. (1994) recorded smuts on five Lepidosperma species from Western Australia, assigning them to the genus Tolyposporium. Vánky and Shivas (2008) have now recorded five smut fungi on 15 Lepidosperma species (Table 6), including the monotypic genus Heterotolyposporium which is only known from L. ensiforme in Tasmania (Vánky and Shivas, 2008; Lutz et al., 2012). Additional records have recently been made from a broad range of Lepidosperma species from south-western and south-eastern Australia but the fungal species are yet to be identified (R. L. Barrett, M. D. Barrett, J. J. Bruhl and K. L. Wilson, pers. obs.; Fig. 11).

Table 6.

Fungal smuts infecting Lepidosperma species

Smut species	Lepidosperma hosts	References
Heterotolysporium lepidospermatis	L. ensiforme	Vánky, 1997a, 1998; Lutz et al., 2012
Moreaua gigaglomerulosa	L. neesii	Vánky and Shivas, 2008
M. lepidospermatis	L. lineare (as L. gunnii), L. sieberi (as L. angustatum), L. semiteres and L. sieberi (as L. concavum)	Vánky and Shivas, 2008
M. megaglomerulosa	L. filiforme, L. laterale, L. longitudinale, L. neesii and L. sieberi (as L. concavum)	Vánky, 1997b
M. rodwayi	L. effusum, L. flexuosum, L. gladiatum, L. laterale, L. lineare (as L. gunnii), L. neesii, L. quadrangulatum, L. sieberi (as L. squamatum), L. viscidum and L. species (indet.)	Vánky and Shivas, 2008
Moreaua rodwayi (as Tolyposporium)	Lepidosperma laterale in New Zealand	McKenzie, 1990

Fig. 11.

Fungal smut-infected spikelets of Lepidosperma costale at Wubin Rocks, Western Australia.

McAlpine (1902) described the ascomycete Metasphaeria lepidospermae from a Lepidosperma species in Victoria near Werribee as having a significant impact on the species, actually killing hundreds of plants. The ascomycete Nemacyclus gilvus was named from dead leaves of L. laterale (Rodway, 1918; Dennis, 1958).

The septorioid fungus Clypeopycnis lepidospermatis (teleomorph Mycosphaerella lepidospermatis) occurs on L. gladiatum (Priest, 2006). The generic placement of this fungus is in doubt and it possibly represents a Cyperaceae-specific genus currently only known from L. gladiatum (Priest, 2006).

Cooke (1891) described Anthostomella lepidosperma from a Lepidosperma species in Victoria. Anthostomella lepidosperma is now considered to be a synonym of A. leptospora (Lu et al., 1999). Coniosporium pterospermum (= Arthrinium pterospermum) has been recorded from Lepidosperma in Victoria (McAlpine, 1895). Hennings (1901) described the Sordariomycete fungus Pestalotia lepidospermatis from L. angustatum in Western Australia. McAlpine and Tepper (1895) described a new stone-maker fungus (Laccocephalum basilapiloides = Polyporus basilapidoides) from the mallee of South Australia, noting that it was regularly found among tussocks of L. viscidum (s.l.).

Mycorrhizal and microbial associations

Generally, Cyperaceae are considered to be non-mycorrhizal (e.g. Powell, 1975). Lepidosperma squamatum (s.l., as L. angustatum) has been recorded as being ‘usually uninfected’ by mycorrhizal fungi (Lamont, 1984). More recently, Meney et al. (1993) have recorded seasonal infection by arbuscular mycorrhizal fungi (Acaulospora sp. and Glomus sp.) in L. gracile (probably = L. leptostachyum). Some authors consider it unlikely that these records represent a true mycorrhizal relationship, although this is difficult to prove conclusively (Brundrett, 2009). Brundrett (2002) suggests that the presence of non-mycorrhizal nutrient acquisition through the presence of dauciform roots may have facilitated the success of the Cyperaceae. This is a common strategy in soils with very low available phosphorus (Lambers et al., 2008). It may be that a mycorrhizal relationship is only present under specific circumstances. In studies of the normally non-mycorrhizal genus Hakea, Boulet and Lambers (2005) found in H. verrucosa, a species with cluster roots similar in function to the dauciform roots found in Lepidosperma, that arbuscules were present in roots in ultramafic soils with high nickel and low phosphorus concentrations. It may be that Lepidosperma species (and other Cyperaceae) are mycorrhizal under certain environmental conditions, which disadvantage the carboxylate-releasing strategy of dauciform roots. Perrier et al. (2006) and Lagrange et al. (2011) have confirmed that arbuscular mycorrhizas are regularly found in the roots of the metallophytic species L. perteres in the metal-rich ultramafic soils of New Caledonia. Muthukumar et al. (2004) concludes that many Cyperaceae should be considered to be mycorrhizal, although often only under particular environmental conditions, with the specific benefits of these relationships still remaining unknown.

Early studies of plant species influence on microbial presence in the rhizosphere in sandy heath in Victoria by Thrower (1954) found a large number of microorganisms associated with the root zone of L. sieberi (as L. concavum): two Oomycetes. seven Zygomycetes. seven Sordariomycetes. two Saccharomycetes. 29 Eurotiomycetes. one Leotiomycete. two Dothideomycetes and one Actinobacteria. The exact nature and ecological implications of the relationship between the plant and rhizosphere mycota remain to be demonstrated. The Sordariomycete fungus Coniella duckerae (Yip, 1987) was described from the rhizosphere of L. sieberi (as. L. concavum).

Pathogenic infection

While it appears that some level of infection can occur (Phillips and Weste, 1984), all Australian Lepidosperma species are considered to be resistant to Phytophthora cinnamomi, possibly due to their ability to produce new roots beyond the infection zone relatively quickly (Phillips and Weste, 1984; Weste et al., 2002). Several species appear to benefit from reduced competition following the death of susceptible taxa in infected areas (Weste, 1981; Podger et al., 1990; Duncan and Keane, 1996; Shearer and Dillon, 1996; Kirkpatrick and Harris, 1999; Cahill et al., 2008; Dunstan et al., 2008; Mordecai, 2011). Weste and Kennedy (1997), Weste et al. (2002) and Weste (2003) recorded a significant long-term increase in the density of L. semiteres in the Grampians, Victoria, in sites affected by P. cinnamomi. Weste (1981) recorded L. sieberi (as L. concavum) becoming dominant following the death of susceptible species due to P. cinnamomi infection near Melbourne, Victoria. Podger et al. (1990) isolated P. cinnamomi from the roots of L. sieberi (as L. concavum), but they did not observe any level of pathogenicity. Shearer et al. (2007) caution that Lepidosperma species may still be at risk from associated habitat change, noting some decline in L. angustatum in southern Western Australia without any signs of direct infection by P. cinnamomi. Changes in plant community structure due to the invasion of P. cinnamomi may have significant effects on animals reliant on plant cover for protection and resistant species such as Lepidosperma become even more important in these situations (Wilson et al., 1994).

Shearer et al. (1998) found that Lepidosperma species are also resistant to the pathogenic fungus Armillaria luteobubalina in coastal areas of Western Australia.

Hosts for hemiparasitic plants

Lepidosperma species have been recorded as natural host plants for Olax phyllanthi (L. gladiatum, Pate et al., 1990), Santalum spicatum (Fox, 1997) and Nuytsia floribunda (R. L. Barrett, pers. obs.), although no particular detrimental impact on the sedges has been observed.

CONCLUSIONS

While specific observations of Lepidosperma ecology are still poorly represented in the literature, most observations being incidental, it is clear that as a genus, sword sedges have an important place in the ecology of many ecosystems. From the scattered records that have been located, it is difficult to determine the full extent of the ecological importance of Lepidosperma species. There are few publications focusing specifically on Lepidosperma and it is likely that the records presented here represent only a small fraction of the real ecological interactions present across the range of the genus. There remains virtually nothing known of various galls, insects that feed on the plants or nematodes that may be associated with Lepidosperma species.

Many of the ecological association records come from rare animal species whose life histories have been studied in detail to aid their conservation. It is likely that a much larger number of more common species also have direct associations with Lepidosperma species that are yet to be recorded in the literature. The genus Lepidosperma, as a major component of many ecosystems in Australia, New Zealand and New Caledonia, is an ideal subject for additional studies on ecological interactions with other organisms that may be dependent on them. Most of the studies to date have been very limited in their assessment of habitat details and the nature and extent of the associations between species. Many opportunities therefore remain to further our understanding of ecological associations with Lepidosperma species. Investigation of the potential for co-speciation of Lepidosperma and Elachista species is likely to provide insights into the evolution of both genera. It is expected that many additional associations will be identified in the future once more attention is paid to the ecology of Lepidosperma.

The extensive nature of the ecological associations documented here for Lepidosperma suggest that similar reviews for sedge genera worldwide would greatly enhance our understanding of sedge ecology. Sedges clearly play a critical role in many ecosystems and their relative importance is often overlooked.