Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Fig. S1. Average distances to centroid for each dispersal mode group and whole biological data. Different
letters indicate groups that are significantly different (P < 0.05). Pairwise comparisons were not made if
the overall PERMDISP test was not significant. I = Iijoki basin, K = Koutajoki basin, T = Tenojoki basin.Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Fig. S2. Environmental heterogeneity (measured as an average distance to centroid) for subsampled sets
of sites (empty symbols) for the three study basins. In the subsampling, eight sites located within an
extent that was equal to the extent in the smallest study area (the Koutajoki basin) were sampled. In the
Koutajoki basin, eight sets of sites were subsampled. In the Iijoki and Tenojoki basins, there were six and
three possible sets of sites, respectively. Also the environmental heterogeneity for all the sites in the given
dataset is shown (red filled symbols).
Iijoki Koutajoki Tenojoki
2.
2
2.
4
2.
6
2.
8
3.
0
3.
2
3.
4
E
nv
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nm
en
ta
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et
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og
en
ei
tyOnline supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Table S1. Total number of taxa detected in each dispersal mode group and in each basin. Proportion of
singletons (i.e. species that had only one individual within a basin) in parentheses.
Number of taxa
Basin PaAq PaTe AcTe All groups
Iijoki 14 (14%) 64 (17%) 63 (17%) 141
Koutajoki 16 (25%) 75 (17%) 68 (0%) 159
Tenojoki 7 (29%) 52 (8%) 39 (26%) 98
All basins 23 112 93 228Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Table S2. Species list for the three study regions. Frequency (number of sites occupied) and mean
abundance at occupied sites are given. Species are grouped into the three dispersal mode groups. Within
orders (and within families for the Diptera) species are in alphabetical order to facilitate reading.
Iijoki basin Koutajoki basin Tenojoki basin
Frequency
Mean
abundance Frequency
Mean
abundance Frequency
Mean
abundance
Passively dispersing species with aquatic adults (PaAq)
Tricladida
Dendrocoelidaesp. 0 0 1 1 0 0
Planariidaesp. 0 0 1 2 0 0
Nematoda
Merminthidaesp. 1 1 2 2 0 0
Oligochaeta
Eiseniella tetraedra 4 3 13 4 2 2
Oligochaetasp. 10 2 15 4 4 3
Hirudinea
Glossiphonia complanata 0 0 1 2 0 0
Gastropoda
Gyraulussp. 0 0 5 9 0 0
Radix peregra 0 0 5 3 1 1
Valvata piscinalis 0 0 1 10 0 0
Bivalvia
Pisidiumsp. 2 1 7 25 0 0
Sphaeriumsp. 3 28 0 0 0 0
Margaritifera margaritifera 1 1 0 0 0 0
Hydracarina
Hydrodroma sp. 2 1 0 0 0 0
Hygrobates longipalpis 9 11 0 0 0 0
Hygrobates nigromaculatus 5 1 0 0 1 1
Hygrobates norvegicus 4 8 0 0 0 0
Hygrobates trigonicus 0 0 0 0 2 1
Lebertiasp. 7 2 1 1 2 1
Limnochares aquatica 2 1 1 1 0 0
Sperchonsp. 16 7 3 2 19 3
Crustacea
Asellus aquaticus 9 4 2 5 0 0
Candona sp. 0 0 1 1 0 0
Gammarus lacustris 0 0 1 9 0 0
Mainly passively dispersing species with terrestrial adults (PaTe)
Diptera: Psychodidae
Berdeniellasp. 5 2 15 8 6 5Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
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M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Diptera: Culicidae
Aedessp. 0 0 4 3 0 0
Culexsp. 3 2 0 0 0 0
Diptera: Dixidae
Dixa submaculata 0 0 1 1 0 0
Diptera: Ceratopogonidae
Bezzia sp. 8 2 11 3 2 3
Diptera: Chironomidae
Apsectrotanypus trifascipennis 0 0 1 1 0 0
Brillia bifida 1 2 6 4 6 2
Brillia longifurca 1 1 1 1 0 0
Bryophaenocladiussp. 0 0 1 1 0 0
Cardiocladius capucinus 0 0 0 0 2 1
Chaetocladius piger 0 0 1 2 1 44
Chaetocladius suecicus 0 0 1 1 0 0
Constempellina brevicosta 0 0 0 0 1 1
Corynoneura celtica 0 0 0 0 3 6
Corynoneura lobata 0 0 0 0 5 1
Corynoneura sp. 9 4 3 1 0 0
Cricotopus pulchripes 0 0 0 0 1 4
Cricotopus annularius 1 1 0 0 0 0
Cricotopus festivellus 4 17 0 0 0 0
Cricotopus laricomalis 3 3 0 0 0 0
Cricotopussp. 0 0 7 2 0 0
Diamesa bertrami 0 0 0 0 1 3
Diamesa incallida 0 0 0 0 1 1
Diamesa insignipes 0 0 1 2 0 0
Diplocladius cultriger 0 0 2 5 0 0
Epoicocladius ephemerae 0 0 1 4 0 0
Eukiefferiella boevrensis 0 0 0 0 1 4
Eukiefferiella brevicalcar 13 10 6 18 2 15
Eukiefferiella claripennis 6 3 6 5 2 1
Eukiefferiella devonica 10 25 6 18 8 6
Eukiefferiella minor 1 1 2 178 2 6
Heleniella ornaticollis 0 0 2 2 2 2
Heterotanytarsus apicalis 3 1 1 5 0 0
Heterotrissocladius marcidus 2 3 2 3 0 0
Krenosmittia boreoalpina 0 0 0 0 1 3
Lasiodiamesa sp. 0 0 1 1 0 0
Limnophyessp. 2 2 0 0 0 0
Macropelopiasp. 1 1 1 1 0 0
Metriocnemus terrester 0 0 1 5 0 0
Metriocnemus fuscipes 1 1 0 0 0 0
Micropsectra atrofasciata 0 0 12 7 21 10
Micropsectra junci 9 29 6 5 0 0
Micropsectra logani 0 0 1 7 0 0Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
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M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Micropsectra notescens 0 0 1 10 0 0
Micropsectra pallidula 5 17 12 5 0 0
Micropsectra recurvata 0 0 1 8 0 0
Microtendipes pedellus 0 0 2 3 0 0
Nanocladius balticus 1 1 0 0 0 0
Nanocladius rectinervis 8 4 2 4 1 1
Natarsia punctata 0 0 1 2 0 0
Odontomesa fulva 1 2 0 0 0 0
Orthocladius excavatus 0 0 0 0 1 15
Orthocladius frigidus 1 2 1 26 1 2
Orthocladius holsatus 0 0 3 2 0 0
Orthocladius lignicola 4 1 2 1 1 2
Orthocladius olivaceus 0 0 0 0 1 3
Orthocladius rhyacobius 0 0 4 2 3 2
Orthocladius rivicola 0 0 0 0 21 7
Orthocladius saxosus 0 0 1 87 1 2
Paracladopelma laminatum 0 0 1 1 0 0
Parakiefferiella bathophila 0 0 0 0 1 6
Parametriocnemus stylatus 2 2 8 6 0 0
Paraphaenocladiussp. 1 1 0 0 0 0
Paratrichocladius rufiventris 0 0 2 3 1 2
Paratrichocladius skirwithensis 0 0 1 8 9 4
Pentaneurella katterjokki 0 0 0 0 3 2
Polypedilum breviantennatum 2 1 3 1 0 0
Polypedilum convictum 3 2 0 0 0 0
Potthastia longimanus 11 2 7 7 8 2
Prodiamesa olivacea 0 0 1 1 0 0
Psectrocladius psilopterus 1 4 0 0 0 0
Pseudodiamesa branickii 1 1 0 0 1 3
Pseudosmittia gracilis 0 0 1 31 2 3
Rheocricotopus atripes 1 1 1 1 0 0
Rheocricotopus effusus 1 2 2 3 0 0
Rheocricotopus fuscipes 7 22 5 7 0 0
Rheopelopiasp. 6 9 7 13 16 5
Rheotanytarsussp. 9 4 5 8 1 5
Stempellina bausei 1 1 1 1 0 0
Stempellinella brevis 8 5 2 3 0 0
Stempellinella edwardsi 0 0 0 0 1 2
Stenochironomussp. 0 0 2 1 0 0
Syndiamesasp. 0 0 1 4 0 0
Synorthocladius semivirens 2 5 4 6 0 0
Tanytarsus curticornis 0 0 1 1 0 0
Thienemanniella clavicorni 1 2 0 0 0 0
Thienemanniella majuscula 0 0 0 0 6 2
Thienemanniella vittata 8 5 3 2 0 0
Thienemannimyiasp. 10 13 11 13 2 1Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Tokunagaiasp. 1 1 1 3 7 3
Trichotanypus posticalis 0 0 0 0 1 1
Trissopelopia longimana 10 10 6 7 11 1
Tvetenia bavarica 2 26 6 9 11 7
Tvetenia calvescens 14 13 13 8 16 4
Tvetenia discoloripes 2 31 8 1 15 6
Zavrelimyia sp. 2 2 4 2 0 0
Diptera: Simulidae
Greniera ivanovae 1 4 0 0 0 0
Helodon ferrugineus 1 3 0 0 0 0
Prosimulium hirtipes 15 37 8 27 18 8
Prosimulium macropyga 2 44 1 93 7 3
Simulium aureum 0 0 1 1 0 0
Simulium beltukovae 2 3 2 5 0 0
Simulium equinum 1 115 0 0 0 0
Simulium lundstromi 1 7 1 6 0 0
Simulium monticola 3 47 3 12 23 15
Simulium murmanum 3 10 0 0 8 6
Simulium noelleri 1 2 0 0 0 0
Simulium ornatum 10 15 13 25 9 2
Simulium paramorsitans 1 4 0 0 0 0
Simulium tuberosum 2 1 0 0 0 0
Simulium vernum 20 173 17 92 19 9
Stegopterna trigonium 3 97 3 104 2 3
Mainly actively dispersing species with terrestrial adults (AcTe)
Diptera: Tipulidae
Tipulasp. 0 0 2 2 0 0
Diptera: Limoniidae
Eloeophila sp. 6 2 7 3 1 1
Molophilussp. 1 1 1 1 0 0
Scleroproctasp. 1 1 0 0 0 0
Diptera: Pediciidae
Dicranota sp. 15 5 14 6 17 3
Tricyphonasp. 0 0 0 0 1 1
Diptera: Empididae
Cheliferasp. 5 4 6 7 3 1
Clinocerasp. 3 1 0 0 0 0
Hemerodromia sp. 2 24 2 11 0 0
Wiedemanniasp. 10 5 3 4 2 1
Diptera: Muscidae
Muscidaesp. 0 0 0 0 1 1
Ephemeroptera
Ameletus inopinatus 11 10 12 7 18 7
Baetis muticus 3 97 12 54 20 30Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Baetis niger 15 78 10 12 10 6
Baetis rhodani 14 158 15 15 29 144
Baetis subalpinus 1 1 0 0 0 0
Centroptilum luteolum 0 0 1 1 0 0
Ephemera danica 0 0 4 4 0 0
Ephemerella aurivillii 9 11 8 19 15 4
Habrophlebia fusca 0 0 6 3 0 0
Habrophlebia lauta 0 0 12 6 0 0
Heptagenia dalecarlica 1 1 6 8 15 7
Heptagenia fuscogrisea 2 1 0 0 0 0
Heptagenia sulphurea 1 3 0 0 0 0
Leptophlebia marginata 9 7 6 2 0 0
Leptoplebia vespertina 4 21 0 0 0 0
Paraleptophlebia cincta 0 0 2 2 0 0
Paraleptophlebia submarginata 0 0 2 5 0 0
Parameletus chelifer 1 1 0 0 0 0
Odonata
Somatochlora metallica 1 1 1 1 0 0
Plecoptera
Amphinemura borealis 1 119 5 15 8 9
Amphinemura standfussi 0 0 1 2 1 1
Amphinemura sulcicollis 14 26 0 0 14 6
Arcynopteryx compacta 0 0 0 0 2 1
Capnia atra 1 2 0 0 3 1
Capnopsis schilleri 1 1 5 4 0 0
Diura bicaudata 3 1 3 1 2 2
Diura nanseni 7 2 4 2 0 0
Isoperla difformis 16 13 1 1 7 4
Isoperla grammatica 0 0 14 16 0 0
Isoperla obscura 0 0 5 2 0 0
Leuctra digitata 7 2 11 8 1 3
Leuctra fusca 1 1 0 0 0 0
Leuctra hippopus 2 2 0 0 19 5
Leuctra nigra 6 12 0 0 4 2
Nemoura sp. 16 29 18 49 28 37
Nemurella pictetii 3 26 0 0 1 1
Protonemura intricata 5 7 8 27 20 31
Protonemura meyeri 18 45 0 0 0 0
Siphonoperla burmeisteri 1 6 3 3 4 3
Xanthoperla apicalis 0 0 2 3 0 0
Coleoptera
Agabussp. 1 5 0 0 0 0
Bagoussp. 1 1 0 0 0 0
Colymbetessp. 0 0 0 0 1 1
Dytiscidaesp. 1 1 0 0 0 0
Elmis aenea 18 42 14 22 10 7Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
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M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Elodessp. 3 1 4 3 0 0
Hydraena gracilis 13 13 8 17 2 1
Hydroporussp. 0 0 0 0 1 1
Illybiussp. 2 10 0 0 0 0
Limnius volckmari 4 21 4 25 0 0
Oulimnius tuberculatus 5 6 7 8 1 1
Megaloptera
Sialis fuliginosa 2 1 6 2 0 0
Trichoptera
Agapetus ochripes 0 0 2 2 0 0
Apataniasp. 3 4 7 12 5 2
Arctopsyche ladogensis 0 0 0 0 1 1
Athripsodessp. 0 0 1 14 0 0
Ceraclea annulicornis 0 0 2 11 0 0
Ceratopsyche silfvenii 1 1 1 4 0 0
Chaetopteryxsp. 0 0 5 2 0 0
Cheumatopsyche lepida 0 0 1 1 0 0
Halesussp. 2 1 6 3 0 0
Hydropsyche angustipennis 0 0 7 1 0 0
Hydropsyche pellucidula 2 8 2 2 0 0
Hydropsyche saxonica 3 3 5 10 0 0
Hydroptilasp. 0 0 1 1 1 1
Lepidostoma hirtum 1 3 2 2 0 0
Limnephilussp. 17 18 2 1 0 0
Micrasema gelidum 13 23 9 9 4 7
Micropterna sequax 0 0 1 1 0 0
Molannodes tinctus 0 0 3 2 0 0
Mystacides sp. 0 0 1 1 0 0
Neureclipis bimaculata 2 4 0 0 0 0
Philopotamus montanus 1 12 1 1 4 2
Plectrocnemia conspersa 10 14 8 9 3 1
Polycentropus flavomaculatus 0 0 7 8 0 0
Polycentropus irroratus 0 0 1 2 0 0
Potamophylax cingulatus 11 4 9 2 3 1
Rhyacophila fasciata 0 0 2 1 0 0
Rhyacophila nubila 6 5 10 5 23 5
Ryacophila obliterata 15 5 10 5 0 0
Sericostoma personatum 4 3 7 6 0 0
Silo pallipes 8 2 1 5 0 0Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Taking the information content of response datasets into account
The response matrices based on the dispersal mode groups (i.e., PaAq, PaTe and AcTe) differ in their
information content (IC = �Pi × (1-Pi), where Piis the proportion of sites occupied by the i
th species;
Table S3) due to the different number of species and patterns of rarity and commonness (see Lennon et al.
2004 and Siqueira et al. 2012).  To take the likely effects of these differences in the information content
into account, we randomly sampled species in each response matrix with high information content to
obtain datasets (response matrices) with similar information contents  (± 0.03).
Here, all PaAq datasets exhibited the lower information contents within regions (Table S3). Therefore, we
randomly sampled species from PaTe and AcTe to create smaller datasets with similar information
content (equal to PaAq ±0.03). We created 999 datasets representing the responses matrices for PaTe and
999 for AcTe and conducted the pRDA for each of these datasets. Then we calculated the mean and
standard deviation (SD) for each resampled case (see Tables S4 and S5).
References
Lennon, J. J., Koleff, P., Greenwood, J.J.D., Gaston. K.J. (2004) Contribution of rarity and commonness
to patterns of species richness. Ecology Letters, 7, 81–87.
Siqueira, T., Bini, L.M., Roque, F.O., Marques Couceiro, S.R., Trivinho-Strixino S. & Cottenie, K.
(2012) Common and rare species respond to similar niche processes in macroinvertebrate
metacommunities. Ecography, 35, 183–192.
Table S3: Number of species and information content (IC) within each dataset.
Dataset Group N species IC
All PaAq 23 1.72
PaTe 112 8.43
AcTe 93 9.12
Iijoki PaAq 14 2.13
PaTe 64 7.89
AcTe 63 8.39
Koutajoki PaAq 16 1.705
PaTe 75 8.9
AcTe 68 10.44
Tenojoki PaAq 7 0.59
PaTe 52 5.7
AcTe 39 4.56Online supporting information
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional
environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Table S4. Adjusted R2 values and p-values for each dispersal mode group and all taxa, in each basin and
across basins based on observed data (obs.). Also the number of significant models (of the total of 999)
when taking the information content into account is given in column ”P, n>0.05”. Fractions are as
follows: [a+b] =  environmental, [b+c] = spatial.
Group
[a+b] [b+c]
Basin Adj. R2 obs. P obs. P n<0.05 Adj. R2 obs. P obs. P n<0.05
Overl. Waterc. Overl. Waterc. Overl. Waterc. Overl. Waterc. Overl. Waterc.
Iijoki PaAq 0.028 0.280 0.260   0.060 0.064 0.160 0.058
PaTe 0.068 0.084 0.115 252 254 0.038 0.060 0.220 0.051 267 290
AcTe 0.174 0.005 0.005 557 556 0.065 0.052 0.140 0.090 136 266
All
taxa 0.15 0.005 0.005 0.062 0.050 0.090 0.058
Koutajoki PaAq 0.08 0.170 0.090 0.014 0.039 0.410 0.200
PaTe 0.109 0.017 0.005 309 309 0.013 0.011 0.340 0.290 75 17
AcTe 0.107 0.015 0.013 331 334 0.056 0.012 0.150 0.290 35 41
All
taxa 0.12 0.005 0.005 0.045 0.013 0.140 0.330
Tenojoki PaAq -0.03 0.640 0.660 -0.103 -0.075 0.910 0.930
PaTe 0.028 0.190 0.150 139 136 0.091 0.097 0.015 0.005 296 388
AcTe 0.217 0.005 0.005 423 427 -0.039 0.035 0.540 0.340 51 134
All
taxa 0.115 0.005 0.020 0.058 0.095 0.120 0.020
All
Basins
PaAq 0.171 0.005 0.067 0.005
PaTe 0.201 0.005 980 0.132 0.005 979
AcTe 0.306 0.005 999 0.136 0.005 998
All
taxa 0.278 0.005   0.144 0.005Online supporting information Page 12 / 13
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Table S5. Pure fractions for each dispersal mode group and all taxa, in each basin and across the basins when using overland distances. Fractions and p-values
are given based on observed data (obs.). The mean and standard deviation (SD) for each fraction and the number of significant models (n P<0.05) when taking
the information content into account (999 resamplings) are given. Significant fractions are highlighted in bold. Fractions are as follows: [a] = pure
environmental, [b] = shared, [c] = spatial, [d] = unexplained.
[a] [b] [c] [d]
  Basin Group
Adj. R2
obs.
Adj. R2
mean±SD
P
obs.
n
P<0.05
Adj. R2
obs.
Adj. R2
mean±SD
Adj. R2
obs.
Adj. R2
mean±SD
P
obs.
n
P<0.05
Adj. R2
obs.
Adj. R2
 mean±SD
O
ve
rl
an
d
Iijoki PaAq 0.050 0.26 -0.022 0.082 0.12 0.889
PaTe -0.032 -0.001 ± 0.069 0.65 30 0.100 0.072 ± 0.05 -0.062 -0.001 ± 0.085 0.83 47 0.994 0.931 ± 0.106
AcTe 0.155 0.144 ± 0.107 0.03 436 0.019 -0.004 ± 0.076 0.046 0.053 ± 0.066 0.20 97 0.780 0.806 ± 0.108
All taxa 0.105 0.05 0.045 0.017 0.39 0.832
Koutajoki PaAq 0.133 0.11 -0.053 0.067 0.21 0.853
PaTe 0.134 0.13 ± 0.098 0.03 367 -0.025 -0.045 ± 0.07 0.038 0.057 ± 0.072 0.33 90 0.853 0.857 ± 0.106
AcTe 0.049 0.052 ± 0.099 0.20 143 0.058 0.04 ± 0.07 -0.002 -0.020 ± 0.091 0.5 25 0.896 0.928 ± 0.12
All taxa 0.077 0.06 0.043 0.002 0.45 0.878
Tenojoki PaAq -0.046 0.71 0.016 -0.119 0.93 1.149
PaTe 0.070 0.065 ± 0.08 0.03 200 -0.042 -0.04 ± 0.064 0.133 0.147 ± 0.101 0.01 369 0.838 0.828 ± 0.115
AcTe 0.188 0.138 ± 0.126 0.03 381 0.029 -0.03 ± 0.064 -0.068 0.043 ± 0.09 0.86 44 0.850 0.849 ± 0.106
All taxa 0.110 0.04 0.005 0.053 0.17 0.832
All basins PaAq 0.102 0.01 0.069 -0.002 0.51 0.831
PaTe 0.074 0.062 ± 0.027 0.01 860 0.127 0.094 ± 0.063 0.005 0.003 ± 0.009 0.105 121 0.794 0.84 ± 0.065
AcTe 0.164 0.135 ± 0.052 0.01 979 0.142 0.118 ± 0.045 -0.006 -0.003 ± 0.006 1 31 0.700 0.75 ± 0.06
All taxa 0.131 0.01 0.147 -0.003 0.84 0.725Online supporting information Page 13 / 13
Metacommunity structuring in stream networks: roles of dispersal mode, distance type and regional environmental context
M. Grönroos, J. Heino, T. Siqueira, V.L. Landeiro, J. Kotanen & L.M. Bini
Table S6. Pure fractions for each dispersal mode group and all taxa, in each basin when using watercourse distances. Fractions and p-values are given based on
observed data (obs.). The mean and standard deviation (SD) for each fraction and the number of significant models (n P<0.05) when taking the information
content into account (999 resamplings) are given. Significant fractions are highlighted in bold. Fractions are as follows: [a] = pure environmental, [b] = shared,
[c] = spatial, [d] = unexplained.
[a] [b] [c] [d]
  Basin Group
Adj. R2
obs.
Adj. R2
mean±SD
P
obs.
P
n<0.05
Adj. R2
obs.
Adj. R2
mean±SD
Adj. R2
obs.
Adj. R2
mean±SD
P
obs.
P
n<0.05
Adj. R2
obs.
Adj. R2
 mean±SD
W
at
er
co
ur
se
Iijoki PaAq -0.001 0.49 0.029 0.035 0.29 0.937
PaTe 0.032 0.057 ± 0.062 0.29 150 0.036 0.013 ± 0.05 0.024 0.044 ± 0.054 0.25 165 0.908 0.886 ± 0.073
AcTe 0.121 0.103 ± 0.099 0.04 364 0.053 0.037 ± 0.05 -0.001 0.012 ± 0.047 0.54 56 0.827 0.847 ± 0.106
All taxa 0.112 0.02 0.039 0.011 0.30 0.838
Koutajoki PaAq -0.004 0.52 0.084 -0.045 0.85 0.965
PaTe 0.113 0.091 ± 0.076 0.02 312 -0.004 -0.006 ± 0.03 0.015 -0.003 ± 0.037 0.27 17 0.876 0.918 ± 0.077
AcTe 0.121 0.095 ± 0.078 0.02 289 -0.014 -0.004 ± 0.032 0.026 0.018 ± 0.037 0.15 21 0.867 0.89 ± 0.084
All taxa 0.120 0.01 0.001 0.012 0.35 0.867
Tenojoki PaAq -0.104 0.95 0.074 -0.149 0.99 1.179
PaTe 0.061 0.049 ± 0.068 0.03 145 -0.032 -0.024 ± 0.061 0.129 0.12 ± 0.125 0.01 397 0.843 0.855 ± 0.123
AcTe 0.155 0.124 ± 0.094 0.03 401 0.063 -0.015 ± 0.055 -0.028 0.062 ± 0.083 0.59 177 0.811 0.829 ± 0.098
All taxa 0.088 0.04 0.027 0.068 0.06 0.817