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. 2014 Mar 24;9(3):e92588. doi: 10.1371/journal.pone.0092588

Species Composition, Distribution and Habitat Types of Odonata in the iSimangaliso Wetland Park, KwaZulu-Natal, South Africa and the Associated Conservation Implications

Lorinda A Hart 1, Meyrick B Bowker 1, Warwick Tarboton 1, Colleen T Downs 1,*
Editor: Ben J Mans2
PMCID: PMC3963920  PMID: 24662948

Abstract

Maputaland–Pondoland–Albany, South Africa has been identified as a biodiversity hotspot and centre for endemism. Odonata make good indicators of freshwater ecosystem health. Consequently we compiled a list of Odonata species recorded to date in the iSimangaliso Wetland Park. We then detailed important species in terms of endemism, conservation status, and potential as indicator species. Finally, we compared Odonata assemblages of different sites sampled within the park to illustrate habitat importance. Species identified during two formal surveys and incidental observations made during the study period were combined with an existing database to compile an accurate and up to date species list for the iSimangaliso Wetland Park. Data from this study were then analyzed to determine which water bodies had the most similar species composition. The Dragonfly Biotic Index (DBI) value of each study area was also determined. We recorded 68 odonate species in the iSimangaliso Wetland Park, adding 13 species to the Ezemvelo KwaZulu-Natal Wildlife database for the area. This brings the total number of Odonata species for the iSimangaliso Wetland Park to 86. Eight species are red-listed, 12 are restricted in South Africa to the coastal plains of northern KwaZulu-Natal, and the remainder occurs widely across the southern African savanna. Analyses indicate that species odonate assemblages were most similar in water bodies with comparable habitats. iSimangaliso Wetland Park is identified as an important area for Odonata diversity and endemism, a trend also reflected by the DBI values. Shifts in the existing species assemblages would indicate changes within the ecosystem and thus this species account provides necessary baseline data for the area. Species Conservation efforts should thus target water bodies of varying habitat types to protect greater species diversity.

Introduction

Freshwater ecosystems contain 10% of current recorded species and comprise only 1% of Earth's surface [1]. They are considered one of the most jeopardized ecosystems [2] and their importance as a resource in undeniable. To better monitor the state and health of these ecosystems, indicator species are often used. Odonata (dragonflies) make particularly good indicators of freshwater ecosystem health as they are visible above water, but rely on the quality of the water and surrounding habitat to persist [3], [4]. Among insects Odonata have comparatively long life cycles and as a group are well defined and studied [3][5]. They have an aquatic larval stage that can last up to one year and a terrestrial adult phase, with males holding favourable territories in many species [6]. Consequently, they serve as indicators for changes in both water quality and surrounding vegetation [7], [8]. Their value as flagship species for freshwater conservation is further highlighted by their important role within freshwater ecosystem species assemblages and their presence on all continents, with the exception of Antarctica [3], [4]. Odonata assemblages can also be used as surrogates to determine aquatic areas for conservation prioritization [9].

iSimangaliso Wetland Park (iWP), South Africa, is known for rich diversity and unique habitats and is therefore a Ramsar wetland of global significance and a UNESCO World Heritage Site. It is located within Maputaland at a significant intersection, with the coastal lowlands bordered by the ocean to the east and an inland plateau to the west [10]. Maputaland's position lends itself to colonization by tropical biota from the north and sub-tropical and temperate biota from both the south and high altitude west [10]. Being a transition zone between these environments has resulted in great biodiversity [10]. Maputaland's conservation value as a centre of endemism is internationally recognised [11]. Today it is accepted that predominantly tropical species are found in the area, largely due to warm ocean currents flowing south from Mozambique, presenting a rich and diverse ecosystem at relatively high latitude [10]. It is unique as it is made up of several habitat types including estuaries, coastal/marine habitats, freshwater lakes and rivers, wetlands, dune and coastal and swamp forests, and mangroves. Many of the vegetation units are vulnerable or endangered outside of the protected iWP, where agricultural practices and invasive alien plants pose the biggest threats [12]. Africa's largest estuarine system, Lake St. Lucia, and southern Africa's largest natural freshwater lake, Lake Sibaya, are both found within iWP [13], [14].

Within South Africa, Maputaland–Pondoland–Albany (MPA) has been identified as a hotspot with the greatest Odonata richness, particularly for red-listed species [9]. The iWP's diverse odonate fauna is due to the subtropical climatic conditions with relatively high rainfall, and variable landscapes and wetland types within the park. Odonata assemblages are associated with different habitat types [15]. Consequently, increased habitat heterogeneity can lead to increased Odonata diversity at a particular site [16], [17]. Of South Africa's 162 taxa, one quarter are Red Listed [9]. The greatest threats to Odonata are those that alter the natural landscape [17]. These include: invasive tree species which cause excessive shading, urbanization, pollution, damming, mining, and introduced fish species [9], [17][19] to name a few.

Disturbance to these habitats can result in a reduction of odonate species [7]. Odonata assemblages should therefore be monitored to recognize what effect human actions have on water quality [20]. Therefore species lists for wetland areas are important as these will serve as baseline data and may indicate changes within the ecosystem. Furthermore, information on hotspots within a reserve can serve as focal points for management to direct cost-effective conservation strategies [21]. Finally, it is important that all habitat types be surveyed within an area as these can yield different species assemblages.

As the MPA is a biodiversity hotspot and centre for endemism, and Odonata are indicators of freshwater ecosystem health, the aim of this study was to determine the Odonata diversity of the iWP. In addition we compared the odonate species composition at different sites to illustrate habitat importance. From this odonate data we detailed important species in terms of endemism, conservation status, and potential as indicator species. It was predicted that odonate species assemblages would differ at sites that varied in habitat type, and so affect conservation management strategies.

Materials and Methods

Study area

The iWP (26°51′S–28°26′S; 32°09′E–32°53′E) extends along the coastal plain of north-eastern KwaZulu-Natal (KZN) Province of South Africa and covers an area of 332000 ha. It stretches from Maphelana in the south to the Mozambique border, north of Kosi Bay, in the north and extends inland for approximately 50 km to include Mkhuze Game Reserve (Fig 1). In general most of the park is less than 40 m above sea-level, with the exception of Mkhuze Game Reserve (c. 60–100 m). Rainfall varies greatly, with the coastal area receiving 1000–1100 mm annually and decreasing to 600 mm in the west at the foot of the mountain range [22].

Figure 1. Map of study area.

Figure 1

Grey shaded areas indicate the iSimangaliso Wetland Park.

We had permission from the local conservation authority for the odonate species surveys. The iWP was divided into three sections; north (Fig 2), central (Fig 3) and south (Fig 4). Within these sections a total of fifty sites were identified and numbered accordingly (Table 1; Fig. 2, 3, 4). For brevity, site names were abbreviated from Kosi Bay to Kosi, Mkhuze Game Reserve to Mkhuze, etc. Most sites were photographed and a description of each site was provided (Table 1). GPS co-ordinates, air temperature, and the total dissolved solids (TDS) of the water were also recorded for each site (Table 1). TDS was measured using Milwaukee Instruments CD97 Total Dissolved Salts (TDS) meter.

Figure 2. Map of the northern section of the iSimangaliso Wetland Park.

Figure 2

The numbers 1–6 represent the positions of sample sites described in Table 1.

Figure 3. Map of the central section of the iSimangaliso Wetland Park.

Figure 3

The numbers 7–27 represent the positions of sample sites described in Table 1.

Figure 4. Map of the southern section of the iSimangaliso Wetland Park.

Figure 4

The numbers 28–50 represent the positions of sample sites described in Table 1.

Table 1. Description of study sites in each area surveyed.

Area Site No. Site name Site Description Latitude Longitude Temp. (°C) Humidity (%) TDS (ppm) No. of Species
Kosi 1 Kosi 10 ha rain-filled grassy pan in grassland. 26.952050 32.802417 35.3 41 56 12
Kosi 2 Kosi Forested stream. 26.957267 32.829883 104 14
Kosi 3 Kosi campsite & jetty Edge of lake. 26.960200 32.826967 650 7
Kosi 4 Kosi Swamp forest stream. 26.955033 32.828833 31.2 40 101 4
Kosi 5 Inlet to 4th Lake Narrow inlet, Nymphaea. 27.040300 32.818917 97 20
Sibaya 6 Sibaya Eastern shore 27.395650 32.711633 30.5 58 95 7
Ozabeni 7 Samango Crossing Flowing stream in forest 27.617467 32.549183 12
Ozabeni 8 Neshe Pan Open water, Nymphaea. 27.654700 32.402650 28.1 58 221 14
Mkhuze 9 Nhlonhlela Bush Camp Floodplain below a nearly dry reedbed 27.597450 32.198167 97 3
Mkhuze 10 Rhino wallow Small 50×10 m, shallow, seasonally rain-filled wallow with emergent grass. Disturbed by game. 27.607817 32.167400 210 4
Mkhuze 11 Rhino wallow Small 50×10 m, shallow, seasonally rain-filled wallow with emergent grass. Disturbed by game. 27.621733 32.185733 120 2
Mkhuze 12 Mbonene Pan Small, rain-filled, grass edge. 27.632817 32.262767 30 54 53 7
Mkhuze 13 Ophansi bridge Mkuze river bridge, fast-flowing, mud-laden River 20 m wide, fringed by degraded fig forest. 27.598750 32.302083 24/25.9* 75* 297/255* 5/10*
Mkhuze 14 Nsumo Pan Bridge at first inlet 3 m wide open water channel fringed by flooded grass. 27.656600 32.301417 21/32* 49* 405/175* 3/12*
Mkhuze 15 Nsumo Pan West hide open water, with reeds along edge 27.665117 32.302150 33.5 51 139 7/2*
Mkhuze 16 Nsumo Pan Picnic site Open water, with reeds along edge. 27.668750 32.305400 324 5/5*
Mkhuze 17 Fig Forest First bridge 10 m wide open water channel fringed by flooded grass and thick bush. 27.668783 32.316717 21/13*
Mkhuze 18 Fig Forest Second bridge strongly flowing, mud-laden river fringed by tall fig forest and shrubby understory. 27.669517 32.322850 340/231* 8/9*
Mkhuze 19 near Nxwala Camp Shaded, stagnant residual pond on seasonal drainage line in dense bush. 27.703150 32.284333 32.1/24* 48 96/144* 11/5*
Mkhuze 20 Nsumo Nxwala side Lily-covered channel backfill from Nsumu Pan. Nymphaea covered water below fever trees. 27.692050 32.291050 155 12/7*
Mkhuze 21 Nsumo Nxwala side Nsumo western inlet, flooded grass below fever trees 27.686550 32.292433 363 8
Mkhuze 22 Nsumo Nxwala side Nsumo western inlet, flooded grass below fever trees 27.689783 32.293600 23 7/12*
Mkhuze 23 Ediza Inlet, dense flooded grass 27.606617 32.288250 31.8 44 4
Mkhuze 24 Rhino wallow Small 50×10 m, shallow, seasonally rain-filled wallow with emergent grass. Disturbed by game. 27.692517 32.278633 91 7
Mkhuze 25 Mkhuze Rain-filled quarry, open water with flooded grass edges. 27.685833 32.238167 27 4
Mkhuze 26 Noshoshela dam Dam of 2 ha, open water fringed by fever trees. 27.756983 32.297300 32.3 43 98/140* 10/22*
Mkhuze 27 uMkhumbe dam Dam of 1 ha, open water fringed by extensive flooded grass with narrow channel of flowing water below the dam. 27.775117 32.297800 28 169/98* 18/13*
E Shores 28 E Shores Grassy pan. 28.118083 32.506783 29.7 57 225 11
E Shores 29 E Shores Small pan. 28.118417 32.515467 28.2 58 3
E Shores 30 E Shores Forested causeway and Mfabeni Swamp. 28.131117 32.527167 34.8 47 345 8
E Shores 31 E Shores Forested causeway and Mfabeni Swamp. 28.137000 32.534683 32.8 61 280 10
E Shores 32 E Shores Lake Bangazi road. 28.141367 32.541100 24 68 6
E Shores 33 E Shores Barbet Pan. 28.194633 32.489200 28 60 225 8
E Shores 34 Cape Vidal house Garden and road. 28.146333 32.547933 32 55 3
E Shores 35 E Shores Forested stream and old excavations. 28.205900 32.490700 12
E Shores 36 Catalina jetty Freshwater edge on Lake St Lucia. 28.220650 32.487283 32.3 58 174 8
E Shores 37 E Shores Freshwater seep on Lake St Lucia edge. 28.238867 32.486950 Seep 63, Lake 974 20
E Shores 38 E Shores Forested causeway and Mfabeni Swamp. 28.137550 32.538567 7
E Shores 39 E Shores Dense flooded sedge beds. 28.296617 32.434383 10
E Shores 40 E Shores Freshwater seep on swamp-forest edge. 28.297150 32.440900 27 59 85 13
E Shores 41 E Shores Two rhino, open grassy pans. 28.316500 32.433717 26.9 67 85 13
E Shores 42 E Shores Papyrus choked pond. 28.318550 32.427050 31.8 64 129 3
E Shores 43 E Shores Two grassy pans divided by causeway. 28.318583 32.430400 32.5 61 88 10
E Shores 44 E Shores Warthog grassy pan. 28.268267 32.466783 33.9 53 110 3
W Shores 45 W Shores St Lucia estuary bridge, reedbed. 28.369783 32.409667 31 63 7
W Shores 46 Ndonyena Small lily pond. 28.352850 32.385350 31.6 57 101 3
W Shores 47 Mpati Weir Flowing stream under forest canopy 28.331200 32.361367 32.4 54 97 5
W Shores 48 Mpati River Stream low, not flowing, choked with Phragmites 28.298467 32.383600 34.4 51 536 10
W Shores 49 W Shores Hippo pan, open grassy. 28.255017 32.393750 34.1 50 108 8
W Shores 50 Makakatana Bay Saline open water, bare edges. 28.248900 32.419617 33.5 46 940 4

Site numbers refer to site positions marked on Fig 1. ‘*’ indicates a second reading or count for the same site.

Odonata identification and analyses

A checklist for possible species in the area was compiled using the database compiled by Ezemvelo KwaZulu-Natal Wildlife (EKZNW), which listed 486 records of 70 odonate species for the iWP (Table 2). Nearly 52% of these records were collected from 1997–2001 and are accredited to Samways and the University of KwaZulu-Natal. Records and a dragonfly collection for St. Lucia and elsewhere in the iWP held at the National Museum in Pretoria (Ditsong) from Balinsky [23], [24] were also consulted. Finally, three species were added from literature searches.

Table 2. Species presence in each region and the number of sites at which they were recorded.

Family Species Common name Samango Crossing Mkhuze Neshe Pan E & W Shores Lake Sibaya Kosi Bay EKZNW database Other records No. of our sites
Calopterygidae Phaon iridipennis Glistening Demoiselle yes yes yes 4
Chlorocyphidae Platycypha caligata Dancing Jewel yes yes yes yes 6
Coenagrionidae Aciagrion dondoense Opal Slim yes
Coenagrionidae Africallagma glaucum Swamp Bluet yes yes
Coenagrionidae Agriocnemis exilis Little Whisp yes yes yes 3
Coenagrionidae Agriocnemis falcifera White-masked Whisp yes yes
Coenagrionidae Agriocnemis gratiosa Gracious Whisp yes
Coenagrionidae Agriocnemis ruberrima Orange Whisp yes yes yes 2
Coenagrionidae Azuragrion nigridorsum Black-tailed Bluet yes yes yes yes 5
Coenagrionidae Ceriagrion glabrum Common Citril yes yes yes yes yes 36
Coenagrionidae Ischnura senegalensis African Bluetail yes yes yes yes yes 16
Coenagrionidae Pseudagrion acaciae Acacia Sprite yes yes 1
Coenagrionidae Pseudagrion coeleste Umsingazi Sprite yes yes yes 9
Coenagrionidae Pseudagrion commoniae Black Sprite yes yes 3
Coenagrionidae Pseudagrion hageni Hagen's Sprite yes yes yes yes 5
Coenagrionidae Pseudagrion hamoni Hamon's Sprite yes yes yes 8
Coenagrionidae Pseudagrion kersteni Kersten's Sprite yes yes 3
Coenagrionidae Pseudagrion massaicum Masai Sprite yes yes yes yes 17
Coenagrionidae Pseudagrion sublacteum Cherry-eye Sprite yes yes 4
Platycnemididae Elattoneura glauca Common Threadtail yes yes yes 3
Lestidae Lestes pallidus Pallid Spreadwing yes 4
Lestidae Lestes tridens Spotted Spreadwing yes yes yes 2
Lestidae Lestes uncifer Sickle Spreadwing yes
Gomphidae Ictinogomphus ferox Common Tigertail yes yes yes yes yes yes 14
Gomphidae Paragomphus cognatus Rock Hooktail yes yes 2
Gomphidae Paragomphus genei Green Hooktail yes yes yes yes 3
Aeshnidae Zosteraeschna minuscula Friendly Hawker yes
Aeshnidae Anaciaeschna triangulifera Evening Hawker yes yes 1
Aeshnidae Anax ephippiger Vagrant Emperor yes yes yes yes 9
Aeshnidae Anax imperator Blue Emperor yes yes yes yes yes 10
Aeshnidae Anax speratus Orange Emperor yes 1
Aeshnidae Anax tristis Black Emperor yes
Aeshnidae Gynacantha manderica Little Dusk-Hawker yes 2
Aeshnidae Gynacantha usambarica Usambara Dusk-Hawker yes yes 2
Aeshnidae Gynacantha villosa Hairy Dusk-Hawker yes
Corduliidae Hemicordulia africana African Emerald yes yes 1
Corduliidae Phyllomacromia contumax Two-banded Cruiser yes yes yes yes 3
Corduliidae Phyllomacromia picta Darting Cruiser yes 2
Libellulidae Acisoma panorpoides Pintail yes yes yes yes 10
Libellulidae Aethriamanta rezia Pygmy Basker yes yes yes 2
Libellulidae Brachythemis leucosticta Banded Groundling yes yes yes yes yes 34
Libellulidae Bradinopyga cornuta Don-Dwala yes 1
Libellulidae Chalcostephia flavifrons Inspector yes yes yes yes 8
Libellulidae Crocothemis erythraea Broad Scarlet yes yes yes yes yes 34
Libellulidae Crocothemis sanguinolenta Little Scarlet yes
Libellulidae Diplacodes lefebvrii Black Percher yes yes yes yes 19
Libellulidae Diplacodes luminans Barbet yes yes yes yes yes 14
Libellulidae Diplacodes pumila Dwarf Percher yes yes 1
Libellulidae Hemistigma al bipunctum Pied-Spot yes yes yes yes 23
Libellulidae Macrodiplax cora Cora's Pennant yes yes
Libellulidae Nesciothemis farinosa Black-tailed Skimmer yes yes yes yes yes yes yes 20
Libellulidae Notiothemis jonesi Forest-Watcher yes 1
Libellulidae Orthetrum abbotti Abbott's Skimmer yes yes 2
Libellulidae Orthetrum chrysostigma Epaulet Skimmer yes
Libellulidae Orthetrum hintzi Hintz's Skimmer yes yes yes 3
Libellulidae Orthetrum icteromelas Spectacled Skimmer yes yes yes 4
Libellulidae Orthetrum julia Julia Skimmer yes yes yes yes yes 15
Libellulidae Orthetrum machadoi Machado's Skimmer yes
Libellulidae Orthetrum robustum Robust Skimmer yes yes yes 4
Libellulidae Orthetrum stemmale Strong Skimmer yes yes yes 7
Libellulidae Orthetrum trinacria Long Skimmer yes yes yes yes yes yes 17
Libellulidae Palpopleura jucunda Yellow-veined Widow yes 1
Libellulidae Palpopleura lucia Lucia Widow yes yes yes yes 16
Libellulidae Palpopleura portia Portia Widow yes 2
Libellulidae Pantala flavescens Pantala yes yes yes yes yes 27
Libellulidae Parazyxomma flavicans Banded Dusk-Darter yes 2
Libellulidae Rhyothemis semihyalina Phantom Flutterer yes yes yes yes yes 20
Libellulidae Sympetrum fonscolombii Nomad yes
Libellulidae Tetrathemis polleni Black-Splash yes yes yes yes 9
Libellulidae Tholymis tillarga Twister yes yes 2
Libellulidae Tramea basilaris Keyhole Glider yes yes yes yes yes 28
Libellulidae Tramea limbata Ferruginous Glider yes yes 2
Libellulidae Trithemis aconita Monkshood Dropwing yes 1
Libellulidae Trithemis annulata Violet Dropwing yes yes yes yes yes 15
Libellulidae Trithemis arteriosa Red-veined Dropwing yes yes yes yes yes 16
Libellulidae Trithemis dorsalis Dorsal Dropwing yes
Libellulidae Trithemis furva Navy Dropwing yes yes 1
Libellulidae Trithemis hecate Hecate Dropwing yes yes 1
Libellulidae Trithemis kirbyi Kirby's Dropwing yes yes 3
Libellulidae Trithemis pluvialis River Dropwing yes
Libellulidae Trithemis stictica Jaunty Dropwing yes yes yes 2
Libellulidae Urothemis assignata Red Basker yes yes yes yes yes 14
Libellulidae Urothemis edwardsii Blue Basker yes yes yes yes yes 9
Libellulidae Urothemis luciana St Lucia Basker yes
Libellulidae Zygonyx torridus Ringed Cascader yes
Libellulidae Zyxomma atlanticum Little Dusk-Darter yes yes 1
Total species recorded 12 43 14 39 7 49 70 8 -
Total number counted 86 799 150 1437 16 288 - - -
Dragonfly Biotic Index/Site 1.67 2.05 1.57 2.38 1.86 2.59 - - -
Dragonfly Biotic Index 20 88 22 93 13 127

Previous records from other sources are also presented.

Species names are based on Samways [27], where full names including authors are given.

At each site odonate species were identified and counted. Identification of species was predominantly done using close-focusing binoculars. In many instances at least one individual of each species was caught and examined using a hand-lens to confirm identification and subsequently released. In addition most species were also photographed to provide a permanent record of identification and occurrence. In addition to formal surveys incidental observations were also recorded. Odonata were surveyed in Mkhuze Game Reserve and surrounds for six days in December 2009, and Eastern and Western Shores of Lake St. Lucia, Mkhuze Game Reserve, Lake Sibaya and Kosi Bay were covered over a 10 day period in February 2011. Identifications were made using the two field-guides of Tarboton and Tarboton [25], [26] and Samways [27], and from literature extracts accumulated by Tarboton.

A map of the study sites was created using ESRI ArcView GIS version 3.1. A detailed species list was compiled for iWP. Using this list, the Dragonfly Biotic Index (DBI) for each study area was determined. The DBI assigns a value ranging from 0–9 to each odonate species in South Africa [27]. This value incorporates the geographical distribution, conservation status and sensitivity to habitat change of a species, where a species scoring ‘0’ would be widespread, common and tolerant to human disturbance [27], [28]. To determine the DBI/site, the total DBI for each study area was divided by the number of species recorded at each of these and thus yielded a DBI/site value between 0–9 for each area [29], [30]. To test which study areas were most similar in species composition Non-metric Multidimensional Scaling (NMDS) was run with a Jaccard similarity coefficient (Primer E, ver. 6, UK). For Mkhuze and Kosi Bay, where there was more than one sampling trip, species composition was totalled.

Results

In total 68 species and 3734 individual Odonata were recorded at the study sites. The summation of these data provides evidence for 86 species of odonates occurring in the iWP. From the compiled checklist, two species that are recorded in the EKZNW database were rejected based on our observations. Surveys from this study provide an additional 13 species to the iWP checklist. Based on results from this study, the EKZNW database, and published records [23], [24], [27], [31][33] an annotated checklist for the iWP has been compiled and the DBI for each study area calculated (Table 2). An indication of relative abundance and known occurrence of each species in the iWP is provided in Appendix S1. Family and species nomenclature are revised to the currently accepted position as listed in Samways [27]. Species showed a range of DBI scores, ranging from 0–8. Based on the checklist of 86 species for the iWP the total possible DBI/site is 2.80 (Total DBI = 241; Table 2). In this study 68 species were observed with a total DBI/site of 2.57 (Total DBI = 175; Table 2). When considering the six study areas, the highest DBI/site of 2.59 was at Kosi Bay, while the lowest value of 1.57 was at Neshe Pan (Table 2).

Of the species identified, eight appear in the National Red List of South African Odonata [33], namely: Aciagrion dondoense, Agriocnemis gratiosa, Agriocnemis ruberrima subspecies ruberrima, Pseudagrion coeleste subspecies umsingaziense, Gynacantha villosa, Diplacodes pumila and Urothemis luciana. These species ranges extend north, into Mozambique, with some widely ranging into tropical Africa. Within South Africa, 12 of the identified Odonata have restricted distributions in the coastal plains of northern KwaZulu-Natal. The remaining species occur broadly across the southern African savanna. The 10 most abundant species from this study are largely similar to those in the EKZNW database. These include: Brachythemis leucosticta 920/24/25 (our count/records in EKZNW database/sites present); Hemistigma albipunctum 280/19/21; Pantala flavescens 276/8/26; Crocothemis erythraea 204/12/28; Ceriagrion glabrum 190/25/31; Diplacodes luminans 147/4/12; Tramea basilaris 143/12/27; Diplacodes lefebvrii 114/22/18; Palpopleura lucia 126/20/12; and Ischnura senegalensis 107/16/16. Ceriagrion glabrum, Crocothemis erythraea and Tramea basilaris were present at the most sites surveyed. Two doubtful species we suggest be removed from the checklist are Phyllogomphus brunneus and Ceriagrion suave. Reasons for this are discussed in Appendix S1.

The NMDS plot illustrating the similarity in Odonata species composition between sites, showed that Kosi Bay, Eastern and Western Shores, and Mkhuze were most similar (Fig. 5). Samango Crossing, Neshe Pan and Lake Sibaya were least similar in composition to any of the other study sites (Fig. 5).

Figure 5. Study areas' similarity in species composition.

Figure 5

Multidimensional scaling of study areas namely: Kosi Bay, Eastern and Western Shores, Mkuze, Neshe Pan, Samango Crossing, and Lake Sibaya, based on their Jaccard index similarity matrices using presence/absence data for all Odonata species observed.

Discussion

Based on data from both the formal surveys and incidental observations, 68 odonate species were observed in this study in iWP. Thirteen species not previously recorded for this park were identified. To date 86 species have now been recorded for iWP. This total is just over 50% of the total recorded for South Africa [27]. It also exceeds Kruger National Park (n = 81), an area approximately six fold larger [34], [35]. In Africa more than 80% of odonate species, and over 70% of globally threatened species, occur within protected areas, which are largely fragmented and isolated [36]. The greater Odonata diversity at iWP is largely due to the diverse habitat types present; in particular coastal swamp forest (with Barringtonia), which supports several elusive odonates (e.g. Gynacantha, Hemicordulia and others) that do not range inland. The remaining odonate diversity generally resembles assemblages typical of the (southern) African savanna. Some common savanna species (e.g. Africallagma glaucum, Sympetrum fonscolombii, Pseudagrion kersteni, Paragomphus cognatus, Trithemis kirbyi) are however rare, or absent from the park. This could be due to climatic or other factors, for example pH, which has been shown to be strongly correlated with dragonfly diversity [18] and prevents their range from extending to the coast. Species which favour lentic wetlands dominate iWP assemblages and savanna species dependent on lotic wetlands, especially perennial streams and rivers, are least represented. This reflects the paucity of such biotopes in the park.

DBI's can be used to identify areas of conservation importance [9]. The DBI of the area under which iWP falls, has previously been identified as relatively high and therefore of conservation significance [37]. DBI's provide a useful tool for monitoring changes in odonate assemblages, for example those resulting from invasive alien plant disturbances [28], [38], [39] or changes due to human alteration of ecosystems [40]. The total DBI's observed for Kosi Bay, Eastern and Western Shores, and Mkhuze were considerably higher than values for sites in the Tsitsikamma region, Western and Eastern Cape Provinces in South Africa, although DBI/site values were lower [41]. Higher DBI/site scores can be explained by the presence of fewer, rare species and therefore higher individual DBI scores in an area. Although study areas in iWP had high species numbers, most DBI scores for species were four or less.

Of the Red Listed odonate species the iWP likely plays a significant conservation role for Urothemis luciana and Pseudagrion coeleste subspecies. Gynacantha villosa and usambarica, Hemicordulia africana, Aethriamantra rezia, Chalcostephia flavifrons and Macrodiplax cora, are also species of local interest as their South African ranges are confined to coastal Zululand. The records of Macrodiplax cora in iWP warrant further investigation, as these are the only known occurrences in Africa south of Somalia, of this fundamentally Asian species.

Many sections of iWP remain to be surveyed as some odonate species listed are based on a single known occurrence. Further surveys are required as we believe that Platycypha fitzsimonsi, Lestes plagiatus, Lestes virgatus, Pseudagrion gamblesi, Pseudagrion salisburyense, Pseudagrion sudanicum, Lestinogomphus angustus, Crenigomphus hartmanni, Ceratogomphus pictus, Orthetrum caffrum, Orthetrum guineense, Palpopleura deceptor, Brachythemis lacustris, Trithemis donaldsoni and Zygonoides fuelleborni could be present in this region. Additionally, sites surveyed in Mkhuze indicated seasonal variability (e.g. in numbers of Phaon iridipennis, Gynacantha manderica and Brachythemis leucosticta). The EKZNW database and published records also indicate that several species temporarily extend their ranges into this area from the tropics during high rainfall years. This is not uncommon for these vagile organisms and is a trait which also contributes to their re-colonization of recovering habitats [42]. Such events would contribute to additional Odonata species. Finally, it is also important to cover water bodies of varying sizes as these can also yield different species assemblages [43].

Species composition for Eastern and Western Shores, Mkhuze and Kosi Bay shows a strong similarity. These three zones all include a range of habitat types, including permanent and temporary pans, flowing water, riverine vegetation and some forest. Kosi Bay and Eastern and Western Shores are both on the coastal plain and share a very similar geography.

Species composition for Neshe Pan was dissimilar to the other sites even though geographically it is close (12 km) to the Mkhuze sites. Neshe Pan is very different from the other pans that were sampled. It is a temporary pan on the Mkuze River, is not tree-lined, and is outside of any conservation area. In dry periods the area is cultivated, and these lands are then flooded when the river flows strongly. The vegetation of Neshe Pan is particularly suitable for odonate breeding and survival. The pan is shallow and has thick beds of reeds and large areas of Nymphaea, offering ideal breeding and feeding habitats for the larval stages. It also offers large feeding areas and many territories for adults.

Samango Crossing odonate species composition was least similar to the other water bodies surveyed in this study. This can be explained by the unique habitat there. It has a greater variation of habitat types within a small area when compared to the other sites. It has the typical vegetation of the coastal plain, but also has the fresh water Manzibomvu stream flowing through it. The stream flows beneath a canopy of swamp forest trees and there are inlets of stationary water.

The species composition for Lake Sibaya is also dissimilar to all other sites. This can be ascribed to the nature of this lake. It is positioned just behind the first dune, and is a large, clear lentic system. It is lined with dune forest on its eastern edge, and supports very little aquatic vegetation or reed beds.

Based on results from this study, it is clear that within South Africa in particular, iWP is an important area for the conservation of Odonate diversity. This is largely due to the diverse habitats found within iWP and the potential to be colonized by both tropical and temperate species [10]. Furthermore, iWP is a protected area thereby reducing the direct negative impacts to its water bodies and benefiting from monitoring and management practices. As a population, Odonata fulfil many ecosystem services either directly or indirectly [26]. These are broadly grouped into: provisioning, cultural, supporting, and regulating services [26]. Odonata vary in their sensitivity to environmental change, and while some individual species can indicate change (e.g. [25]); it is recommended that changes in odonate assemblages as a whole be considered as indicators of environmental disturbance [26]. Thus surveys of Odonata diversity, particularly within ecologically important areas such as iWP, are invaluable.

Odonata respond to climatic and environmental changes [42]. In light of global climate change understanding shifts in species assemblages and the associated implications of such changes becomes increasingly important. Logistic constraints highlight the need for an indicator species group to facilitate rapid and continued surveys in a changing environment [30], [44]. The traits of Odonata lend them to fulfill this essential role [7], [8], [30]. Maputaland was recognized for its unique habitat and as an area of significant biodiversity, thereby motivating for the establishment of a large protected area, today known as iWP [45]. The diverse habitat types within the iWP support a great diversity of Odonata, reiterating its role particularly in the conservation of aquatic diversity.

Supporting Information

Appendix S1

Odonata species account for iSimangaliso Wetland Park. Nine families are arranged in taxonomic order, with species accounts appearing alphabetically.

(DOC)

Acknowledgments

We thank EKZNW for making their data available, for accommodation and for the assistance of game guards in their reserves; the Greater St Lucia Wetland Park Authority for access to the iWP; Ricky Taylor, Rob Taylor and Sbu Mfeka for guidance in the iWP; Scotty and Di Kyle for their hospitality and guidance at Kosi Bay; Dave Robertson, Dennis Kelly and Chris Kelly for assistance in the Mkhuze Game Reserve; Michèle Tarboton for her input in the field with spotting and identification; Kerin Bowker for assistance on field trips.

Funding Statement

The authors have no support or funding to report.

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Associated Data

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Supplementary Materials

Appendix S1

Odonata species account for iSimangaliso Wetland Park. Nine families are arranged in taxonomic order, with species accounts appearing alphabetically.

(DOC)


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