Metacommunity ecology meets biogeography: effects of geographical region, spatial dynamics and environmental filtering on community structure in aquatic organisms

Abstract

Metacommunity patterns and underlying processes in aquatic organisms have typically been studied within a drainage basin. We examined variation in the composition of six freshwater organismal groups across various drainage basins in Finland. We first modelled spatial structures within each drainage basin using Moran eigenvector maps. Second, we partitioned variation in community structure among three groups of predictors using constrained ordination: (1) local environmental variables, (2) spatial variables, and (3) dummy variable drainage basin identity. Third, we examined turnover and nestedness components of multiple-site beta diversity, and tested the best fit patterns of our datasets using the "elements of metacommunity structure" analysis. Our results showed that basin identity and local environmental variables were significant predictors of community structure, whereas within-basin spatial effects were typically negligible. In half of the organismal groups (diatoms, bryophytes, zooplankton), basin identity was a slightly better predictor of community structure than local environmental variables, whereas the opposite was true for the remaining three organismal groups (insects, macrophytes, fish). Both pure basin and local environmental fractions were, however, significant after accounting for the effects of the other predictor variable sets. All organismal groups exhibited high levels of beta diversity, which was mostly attributable to the turnover component. Our results showed consistent Clementsian-type metacommunity structures, suggesting that subgroups of species responded similarly to environmental factors or drainage basin limits. We conclude that aquatic communities across large scales are mostly determined by environmental and basin effects, which leads to high beta diversity and prevalence of Clementsian community types.

Lake and catchment‐scale determinants of aquatic vegetation across almost 1,000 lakes and the contrasts between lake types

“…Goncalves‐Souza, Romero, and Cottenie () proposed that the main mechanisms of community assembly are best considered jointly from metacommunity (assemblages are environmentally structured via niche processes) and biogeography (assemblages are spatially structured via dispersal limitation) perspectives. This and other studies (Heino, Soininen, Alahuhta, Lappalainen, & Virtanen, ; Ng, Carr, & Cottenie, ) indicate that small but significant spatial effects also occur at the metacommunity scale, as well as environmental effects at the biogeographical scale, highlighting the importance of considering both processes across contrasting scales.…”

Global patterns in the metacommunity structuring of lake macrophytes: regional variations and driving factors

“…The spatial extent of our study regions varied from 260 km 2 in Norway to 138,000 km 2 in Sweden, but no systematic increase in the effects of spatial processes was noted along with increasing extent. This outcome may be because environmental gradients often become wider with increasing spatial extent, offering more dimensions for environmental filtering to predominate as long as dispersal remains adequate (Leibold et al 2004; Heino et al 2017b). …”

“…10 000 years ago created variable local environmental conditions in the boreal landscape, further affecting present-day community composition of lake macrophytes in Finland. On the other hand, basin identity representing historical effects was an important factor explaining variation in the community structure of different freshwater organism groups in boreal lakes and rivers (Heino et al 2017b). Moreover, we recognize that the present study is the first attempt to account for the historical effects on macrophyte communities at global extents, and therefore, more research on this topic is clearly needed.…”

“…In some cases, history and climate have overcome the effects of local environmental conditions on local communities (Ricklefs and He 2016), whereas the opposite patterns have been found in other cases (Souffreau et al 2015). Some studies have reported that both biogeographic characteristics and local environment have been important in explaining local community structure over broad spatial extents (Heino et al 2017b; Rocha et al 2017). These patterns can also be studied in the context of metacommunities, a discipline that connects biogeography and community ecology (Jenkins and Ricklefs 2011; Leibold and Chase 2018).…”

Geographical gradients in the biodiversity of Chinese freshwater molluscs: Implications for conservation

“…The shared fractions of dispersal/historical effects, geographical location and area/environmental heterogeneity variables also accounted for relatively high amounts of variation in TD.Such large shared fractions are typical in variation partitioning studies(Heino, Soininen, Alahuhta, Lappalainen, & Virtanen, 2017), including those conducted at broad scales(Heino et al, 2015;Schleuter et al, 2012). As for the results of variation partitioning, the variations of all indices explained by shared fractions were higher than that of unique fractions, with the shared effects of the four groups of predictor variables always accounting for the highest proportion of variation.The shared fraction between energy, geographical location and dispersal/historical variables also explained considerable amounts of the variation.…”