Metacommunity Structure of Stream Insects across Three Hierarchical Spatial scales

Abstract

A major challenge in community ecology is to understand the underlying factors driving metacommunity (i.e., a set of local communities connected through species dispersal) dynamics. However, little is known about the effects of varying spatial scale on the relative importance of environmental and spatial (i.e., dispersal related) factors in shaping metacommunities and on the relevance of different dispersal pathways. Using a hierarchy of insect metacommunities at three spatial scales (a small, within‐stream scale, intermediate, among‐stream scale, and large, among‐sub‐basin scale), we assessed whether the relative importance of environmental and spatial factors shaping metacommunity structure varies predictably across spatial scales, and tested how the importance of different dispersal routes vary across spatial scales. We also studied if different dispersal ability groups differ in the balance between environmental and spatial control. Variation partitioning showed that environmental factors relative to spatial factors were more important for community composition at the within‐stream scale. In contrast, spatial factors (i.e., eigenvectors from Moran's eigenvector maps) relative to environmental factors were more important at the among‐sub‐basin scale. These results indicate that environmental filtering is likely to be more important at the smallest scale with highest connectivity, while dispersal limitation seems to be more important at the largest scale with lowest connectivity. Community variation at the among‐stream and among‐sub‐basin scales were strongly explained by geographical and topographical distances, indicating that overland pathways might be the main dispersal route at the larger scales among more isolated sites. The relative effect of environmental and spatial factors on insect communities varied between low and high dispersal ability groups; this variation was inconsistent among three hierarchical scales. In sum, our study indicates that spatial scale, connectivity, and dispersal ability jointly shape stream metacommunities.

As time goes by: 20 years of changes in the aquatic macroinvertebrate metacommunity of Mediterranean river networks

“…Also, in the driest years some river reaches can dry before May, which may constrain larval maturation and then reduce adult flying populations (Bonada et al, 2017 spending their whole life cycle in the water) were environmentally rather than spatially structured in arid land streams (Cañedo-Argüelles et al, 2015;Phillipsen et al, 2015). It is important to notice that our results are scale dependent, since the dispersal abilities of organisms depend on the spatial scale considered (He et al, 2020;Viana & Chase, 2019). Thus, more studies at lower and higher spatial scales are needed to test our hypotheses.…”

“…distant populations and communities could be very similar to each other). These contrasting patterns could be partly explained by differences in the spatial scale used, since it defines the strength of the dispersal gradient (He, Soininen, Deng, & Wang, 2020;Viana & Chase, 2019).…”

Human activities' fingerprint on multitrophic biodiversity and ecosystem functions across a major river catchment in China

“…"-ktotal," "-kinvertebrate," and "-kmicrobial" are for the total, invertebrate-driven, and microbial-driven decomposition rates of leaves and cotton strips, respectively. Solid lines in the below panels show the relationships between taxonomic (b), phylogenetic, (c) and funcional (d) diversity of multitrophic groups and ecosystem multifunctionality with the 95% CI in shade [Colour figure can be viewed at wileyonlinelibrary.com] taxonomic groups (He et al, 2020;Liu et al, 2013;Tonkin et al, 2018).…”

Communities in high definition: Spatial and environmental factors shape the micro‐distribution of aquatic invertebrates

“…The aim of this study was to: (1) assess the role of metacommunity concepts in explaining micro-scale variability in aquatic macroinvertebrate community composition; and (2) identify the main factors shaping variability in the micro-distribution of aquatic K E Y W O R D S benthic organic matter, community drivers, macroinvertebrates, metacommunity, microdistribution macroinvertebrates, distinguishing between spatial and environmental drivers. Based on previous findings (Braccia & Voshell, 2006;Brooks et al, 2005;Diggins & Newman, 2009;Graça et al, 2004;He, Soininen, Deng, & Wang, 2020;Tolonen et al, 2018), we hypothesised a major role of environmental filtering in shaping macroinvertebrate communities at the micro-scale, with a dominance of species sorting mechanisms.…”

“…sampling point) result from multiple interacting factors, including prior oviposition choices (Lancaster & Downes, 2014) and drift from upstream (Lancaster & Belyea, 2006). However, disregarding such colonisation mechanisms, individual taxa may become locally abundant in habitats matching their environmental preferences and then spread to nearby areas with sub-optimal conditions (He et al, 2020 These contrasting distributions may reflect consumptive competition (sensu Schoener, 1983), but could also be due to shared (or opposing) responses to unmeasured environmental variables (Ovaskainen et al, 2017) and/or to similar habitat requirements of different taxa (e.g. Lencioni & Rossaro, 2005;Puntí, Rieradevall, & Prat, 2009).…”