Connectivity and vagility determine spatial richness gradients and diversification of freshwater fish in North America and Europe
The latitudinal species richness gradient (LRG) has been the subject of intense interest and many hypotheses but much less consideration has been given to longitudinal richness differences. The effect of postglacial dispersal, determined by connectivity and vagility, on richness was evaluated for th...
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| Published in | Biological journal of the Linnean Society Vol. 116; no. 4; pp. 773 - 786 |
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| Main Author | |
| Format | Journal Article |
| Language | English |
| Published |
Oxford
Blackwell Publishing Ltd
01.12.2015
Oxford University Press |
| Subjects | |
| Online Access | Get full text |
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| Summary: | The latitudinal species richness gradient (LRG) has been the subject of intense interest and many hypotheses but much less consideration has been given to longitudinal richness differences. The effect of postglacial dispersal, determined by connectivity and vagility, on richness was evaluated for the species‐poor European and North American Pacific and species‐rich Atlantic regional freshwater fish faunas. The numbers of species, by habitat, migration and distributional range categories, were determined from regional species lists for these three realms. The current orientation and past connections of drainage channels indicate that connectivity is greatest in the Atlantic and least in the Pacific. With increasing connectivity across realms, endemism decreased and postglacial recolonization increased, as did the LRG slope, with the greatest richness difference occurring between southern Atlantic and Pacific regions. Recolonizing species tended to be migratory, habitat generalists and from families of marine origin. Diversification, as indicated by species/genus ratios, probability of diversification, taxonomic distinctness and endemicity, declined with increasing latitude in all realms and was least in Europe. Richness patterns are consistent with an LRG driven by the time available for postglacial recolonization and by differences in dispersal ability, with richness differences across realms reflecting differences in dispersal and diversification. |
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| Bibliography: | Figure S1. The percentages of species of South American origin declines to the north for Atlantic (circles) and Pacific (crosses) drainages. Figure S2. Jaccard distances as a function of spatial separation for pairs of regions, when both regions are within the Mississippi Basin (circles) and when one region is inside and one outside the Mississippi Basin (crosses). Fifteen per cent of cross-Basin region distances are smaller than the predicted within-Basin values while 26% of within-Basin values are greater than the predicted cross-Basin values. Figure S3. Jaccard distances between the regional fish faunas of North America, clustered by the flexible β (−0.25) method. Note that Jaccard distances between the Ohio/Tennessee and central Mississippi regional clusters of the Mississippi Basin were as great as those between the regions comprising the arctic (Mackenzie, Yukon) and subtropical clusters (Mexico, Rio Grande) of the Atlantic realm, and the Missouri regions differed even more from the rest of the Mississippi Basin (Jaccard distances 1.30, 1.35 and 1.59 respectively). The lines and letters to the left of the figure indicate some of the Mississippi Basin regions associated with particular Pliocene drainages (H = Hudson Bay/Arctic, P = Great Plains, T = Teays-Mississippi), from Figure 9.3 in Hocutt & Wiley (). Table S1. Numbers of species in the categories listed in Table . Table S2. ANOVA of realm, glaciation, regional species richness on standardised deviates from null model expectation of taxonomic distinctness. Table S3. Analysis of deviance of continent, and latitude effects on probability of diversification. istex:DEE9C6C5C3A08A21E53DB5BFFB7F6B2B786D3074 ark:/67375/WNG-TKVH00D3-T ArticleID:BIJ12638 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 content type line 23 |
| ISSN: | 0024-4066 1095-8312 |
| DOI: | 10.1111/bij.12638 |