Effects of dispersal and environmental heterogeneity on the replacement and nestedness components of β‐diversity

Abstract

Traditionally metacommunity studies have quantified the relative importance of dispersal and environmental processes on observed β-diversity. Separating β-diversity into its replacement and nestedness components and linking such patterns to metacommunity drivers can provide richer insights into biodiversity organization across spatial scales. It is often very difficult to measure actual dispersal rates in the field and to define the boundaries of natural metacommunities. To overcome those limitations, we revisited an experimental metacommunity dataset to test the independent and interacting effects of environmental heterogeneity and dispersal on each component of β-diversity. We show that the balance between the replacement and nestedness components of β-diversity resulting from eutrophication changes completely depending on dispersal rates. Nutrient enrichment negatively affected local zooplankton diversity and generated a pattern of β-diversity derived from nestedness in unconnected, environmentally heterogeneous landscapes. Increasing dispersal erased the pattern of nestedness, whereas the replacement component gained importance. In environmentally homogeneous metacommunities, dispersal limitation created community dissimilarity via species replacement whereas the nestedness component remained low and unchanged across dispersal levels. Our study provides novel insights into how environmental heterogeneity and dispersal interact and shape metacommunity structure.

What can observational data reveal about metacommunity processes?

“…that spatial isolation among habitat patches increases nestedness (Bender et al 2017, Gianuca et al 2017. Similar results have been found in empirical studies showing e.g.…”

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

“…Both turnover and nestedness contributed to the total dissimilarity, although their relative importance varied depending on lake type, mirroring findings for other aquatic biota (Brendonck, Jocqué, Tuytens, Timms, & Vanschoenwinkel, ; Gianuca, Declerck, Lemmens, & De Meester, ; Tonkin, Stoll, Jähnig, & Haase, ). β turnover was much higher in HA lakes compared with other lake types (Figure c).…”

Beta diversity diminishes in a chronosequence of desertification in a desert steppe

“…Our results also suggest that ecological processes related to habitat dispersal and filtering shape heterogeneous communities, (Gianuca et al, ; Shurin, ; Spasojevic, Copeland, & Suding, ), which can form different species community through species replacement along disturbance gradients. Environmental factors were the major drivers of variation in species diversity, however, it should be acknowledged that combining deterministic (i.e., habitat filtering) and stochastic processes should most effectively explain variations among vegetation communities (Myers et al, ; Qian et al, ).…”

“…Species would select suitable environmental conditions where dispersal is favorable within heterogeneous environments, which can increase the importance of species replacement. However, in homogenous environments, the pattern of nestedness‐resultant components would be erased when dispersal increased, which may affect species assemblages (Gianuca et al, ). That pattern is suggestive of desertification promoting community divergence in heterogeneous environments.…”