Varying Patterns on Varying Scales: A Metacommunity Analysis of Nematodes in European Lakes

Abstract

Ecological community patterns are often extremely complex and the factors with the greatest influence on community structure have yet to be identified. In this study we used the elements of metacommunity structure (EMS) framework to characterize the metacommunities of freshwater nematodes in 16 European lakes at four geographical scales (radius ranging from 80 m to 360 km). The site characteristics associated with site scores indicative of the structuring gradient were identified using Spearman rank correlations. The metacommunities of the 174 nematode species included in this analysis mostly had a coherent pattern. The degree of turnover increased with increasing scale. Ordination scores correlated with geographical variables on the larger scales and with the trophic state index on a regional scale. The association of the structuring gradient with spatial variables and the scale-dependent increase in turnover showed that nematode dispersal was limited. The different metacommunity patterns identified at the increasing geographical scales suggested different, scale-related mechanisms of species distribution, with species sorting dominating on smaller and mass effects on larger geographical scales.

Meiofauna as a model to test paradigms of ecological metacommunity theory

“…3, 'specialization'). Studies on meiofauna metacommunities that included different spatial scales found that the relevance of species sorting was scale-dependent, becoming less significant on larger scales, where dispersal-based processes seemed to dominate (Matsuda et al 2015, Dümmer et al, 2016, which is in accordance with general expectations (Leibold & Chase, 2018).…”

“…Some bdelloid rotifers were found to be significantly associated with different habitat types, i.e., lotic, lentic, and terrestrial mosses , different substrate types (mosses vs. lichens; , and particular lichen species (Fontaneto et al, 2011). The nematode metacommunity in lakes responded to trophic state, indicative of bottom-up structuring of these communities (Dümmer et al, 2016).…”

“…In correlative field studies, the role of dispersal-based processes is best considered by examining the spatial structure of metacommunities. In our review, 16 studies analyzed the effect of space on meiofauna, using different ways: (i) by comparing metacommunity patterns between several spatial scales (Fontaneto et al, 2005;Matsuda et al, 2015;Dümmer et al, 2016), (ii) by testing the influence of geographical distances and the non-/linear effects of latitude and longitude (Fontaneto et al, 2011), and (iii) by testing the effect of nonlinear spatial variables modeled according to the geographical distances between sites (Escrivà et al, 2015;Zhai et al, 2015b;Michelson et al, 2016;Castillo-Escrivà et al, 2016a, b, 2017aRosati et al, 2017;de Campos et al, 2018). Most of the studies reported dispersal limitations (Escrivà et al, 2015;Zhai et al, 2015b;Castillo-Escrivà et al, 2016b, 2017aRosati et al 2017;de Campos et al, 2018), fewer dispersal sufficiency Fontaneto et al, 2011;Matsuda et al, 2015;Michelson et al, 2016;de Campos et al, 2018), and in one a significant spatial structure was attributed to a dispersal surplus (Castillo-Escrivà et al, 2016a).…”

“…No dispersal limitations were recorded for rotifers in mosses and lichens either at high altitudes (above 3000 m a.s.l., or on a large regional scale (1000 km, Fontaneto et al, 2011). For nematodes in European lakes, dispersal limitations were suggested, based on the degree of turnover, only at supra-regional scale (500-1000 km) but not on smaller scales (Dümmer et al, 2016). At regional scale, nematodes were found capable of rapidly colonizing newly created habitats (Ptatscheck et al, 2015).…”

Nematode distributions as spatial null models for macroinvertebrate species richness across environmental gradients: A case from mountain lakes

“…The metacommunity in a region becomes a key element when considering local species richness in fragmented habitats (Leibold et al, 2004). However, it is not always easy how to disentangle the relative effects of purely spatial factors from environmental influences; particularly, because the biodiversity patterns may be the result of the spatial scale of analysis when studying community assemblages (Chase, 2014;Dümmer, Ristau, & Traunspurger, 2016;Heino, 2011). In this context, comparing patterns of species distribution between different groups of organisms, with varying dispersal capabilities and environmental tolerances, is an approach to empirically evaluate whether environment prevails over spatial factors in determining the biodiversity patterns at a particular spatial scale (Heino, 2013;Heino & Peckarsky, 2014;Mantyka-Pringle, Martin, & Rhodes, 2013;Urban, Tewksbury, & Sheldon, 2012).…”