The role of ecological drift in structuring periphytic diatom communities

Abstract

The need to understand the influence of high-level factors that shape species richness and population size is becoming more important as global biodiversity losses threaten biotic communities. Here we investigate the influence of ecological drift on periphytic diatom community composition in arctic lakes. If community composition is strongly influenced by drift, we hypothesize that (i) alpha diversity will increase with increasing lake size, due to the decreasing influence of drift-mediated local extinction, (ii) beta diversity will be greatest among small lakes and lowest in large lakes, and (iii) relationships between community size and environmental variables will be strongest in large lakes and weakest in small lakes. Analysis was conducted on periphytic diatoms accrued on artificial substrates in 44 shallow, thermokarst lakes over the 2009 growing season. Limnological and hydrological conditions at each site were described and their influence was removed to minimize the confounding effect of environmental heterogeneity. Alpha diversity was not significantly different among the lake sizes. Total beta diversity was significantly higher in the small lakes than the medium lakes. Beta diversity was primarily attributed to turnover, and small lakes had significantly higher turnover than medium and large lakes, while nestedness was not significantly different among lake-size classes. Periphytic diatom community composition and environmental variables were not significantly concordant in any lake-size class. Our results suggest that drift, as related to habitat size, is not a primary driver of periphytic diatom community composition in shallow, thermokarst arctic lakes.

Sedimentary, littoral and planktic diatoms show different diversity patterns and assembly mechanisms in mountain lakes of the northern European Alps

“…ecological drift, dispersal processes and historical contingency (Ning et al, 2019). Ecological drift may indeed be relevant for diatoms, but this has not yet been directly proven (Remmer et al, 2019). Historical contingencies are known to influence diatom communities, but they ought to influence sedimentary assemblages even stronger than littoral and planktic diatoms (González-Trujillo et al, 2021).…”

Drivers of beta diversity in modern and ancient reef-associated soft-bottom environments

“…Determining the drivers of faunal heterogeneity has long been one of the central questions in ecology-how communities assemble in an ecosystem (Remmer et al, 2019;Stegen et al, 2013). However, more standardized and therefore comparable datasets are needed to help disentangle the drivers of beta diversity (Keil & Chase, 2019).…”