Habitat Attributes Dictate the Roles of Dispersal and Environmental Filtering on Metacommunity Assembly at Coastal Soft-Bottom Ecosystems

Abstract

Tracking the effects of habitat attributes on species distribution is pivotal to the understanding of community assembly across space and time. We used the elements of metacommunity (EMS), which evaluates coherence, turnover, and boundary clumping of species, to access the spatial patterns of nematodes from three coastal habitats with increasing degree to wave exposure, namely, mangroves, estuarine unvegetated tidal flats, and sandy beaches. Each habitat was sampled in four locations, hundreds of kilometers apart from each other. We hypothesized that (1) coastal habitats act as metacommunity boundaries and drive positive turnover and clumped distribution of species and (2) metacommunity structure within coastal habitats depends on the habitats’ degree to wave exposure since wave energy generally decreases sediment heterogeneity and favors connectivity among locations. Habitats were the main drivers of species turnover, with tidal flats harboring a transitional assemblage between mangrove and sandy beach. Metacommunities from the different habitats showed distinct patterns of organization among locations. Mangroves were characterized by species loss, with smaller areas of mangroves harboring a subset of the species pool present on larger areas of mangroves. Tidal flats showed positive species turnover among the different estuaries, with co-occurring species responding as a group to environmental variations. Both patterns indicate environmental filtering as the main driver at these less wave-exposed habitats. At sandy beaches, in contrast, metacommunity displayed a random pattern, suggesting high connectivity among locations. Our study confirmed that habitat attributes may induce distinct mechanisms of metacommunity assembly at coastal soft-bottom ecosystems.

Nematode diversity patterns in mangroves: a review of environmental drivers at different spatial scales

“…A handful of practical techniques for the investigation of trophic interactions of meiofauna is provided by Majdi et al 2020. The structure of biological communities depends on niche-based or dispersal-based processes. For nematodes in mangroves, it has been proposed that the strongest mechanism shaping the community is niche-based, especially species sorting as a consequence of environmental filtering (Brustolin et al 2021). However, the study of Pinto et al (2013), who found a priori different microhabitats to be colonized by similar nematode communities, seems to support the existence of a degree of local stochasticity, which has been suggested to be potentially relevant at local scale (Gansfort et al 2020).…”

“…Recent research in tropical mangrove forests addressed whether environmental filtering is the most powerful mechanism regulating nematode diversity compared to dispersal-based ones, regardless of the spatial scale (Brustolin et al 2021). At the landscape scale, habitat selection shapes nematode community and metacommunity organization in mangroves is most likely the result of the interaction between species sorting and patch-dynamics (Brustolin et al 2021).…”

“…Recent research in tropical mangrove forests addressed whether environmental filtering is the most powerful mechanism regulating nematode diversity compared to dispersal-based ones, regardless of the spatial scale (Brustolin et al 2021). At the landscape scale, habitat selection shapes nematode community and metacommunity organization in mangroves is most likely the result of the interaction between species sorting and patch-dynamics (Brustolin et al 2021). An effective but poorly explored way to unravel patterns of species sorting (intended as the effect of environmental variables, dispersal and stochasticity on the capacity of a given species to colonize a given habitat) is analyzing the β-diversity of a community by partitioning it in its nestedness (species loss) and turnover (species replacement) components (Baselga, 2010).…”

Soil nematode metacommunities in different land covers: Assessment at the local and regional scales

“…Soil nematodes living in the water of soil pores are sensitive to environmental changes (Chen et al., 2021), and their composition is significantly influenced by land covers at different scales (Li, Chen, et al., 2022; Li, Liu, et al., 2022; Luo et al., 2022). The structures of nematode metacommunities and their assembly mechanisms could change in different land covers (Brustolin et al., 2022). Therefore, though challenging, exploring the metacommunity structures of soil nematodes at different spatial scales with multiple land covers would shed light to these interactions.…”