Metacommunity structuring in stream networks: roles of dispersal mode, distance type, and regional environmental context

Abstract

Within a metacommunity, both environmental and spatial processes regulate variation in local community structure. The strength of these processes may vary depending on species traits (e.g., dispersal mode) or the characteristics of the regions studied (e.g., spatial extent, environmental heterogeneity). We studied the metacommunity structuring of three groups of stream macroinvertebrates differing in their overland dispersal mode (passive dispersers with aquatic adults; passive dispersers with terrestrial adults; active dispersers with terrestrial adults). We predicted that environmental structuring should be more important for active dispersers, because of their better ability to track environmental variability, and that spatial structuring should be more important for species with aquatic adults, because of stronger dispersal limitation. We sampled a total of 70 stream riffle sites in three drainage basins. Environmental heterogeneity was unrelated to spatial extent among our study regions, allowing us to examine the effects of these two factors on metacommunity structuring. We used partial redundancy analysis and Moran's eigenvector maps based on overland and watercourse distances to study the relative importance of environmental control and spatial structuring. We found that, compared with environmental control, spatial structuring was generally negligible, and it did not vary according to our predictions. In general, active dispersers with terrestrial adults showed stronger environmental control than the two passively dispersing groups, suggesting that the species dispersing actively are better able to track environmental variability. There were no clear differences in the results based on watercourse and overland distances. The variability in metacommunity structuring among basins was not related to the differences in the environmental heterogeneity and spatial extent. Our study emphasized that (1) environmental control is prevailing in stream metacommunities, (2) dispersal mode may have an important effect on metacommunity structuring, and (3) some factors other than spatial extent or environmental heterogeneity contributed to the differences among the basins.

Time‐restricted flight ability influences dispersal and colonization rates in a group of freshwater beetles

“…But morphological dispersal traits do not necessarily explain species occurrences (e.g., Grönroos et al., 2013; Schulz, Siqueira, Stefan, & Roque, 2012), and dispersal events driven by physiological or behavioral factors with no relationship to morphological traits are well documented among larger vertebrates (Bekoff, 1977; Duckworth & Badyaev, 2007). These physiological or behavioral factors have also been proposed to be important for invertebrate species (Clobert, Galliard, Cote, Meylan, & Massot, 2009; Hanski et al., 2004), yet we know very little about the seasonal variability and stressors generating nonmorphological differences in flight abilities and how this may influence local and regional occurrences of invertebrate species (Bilton, 2014; Bilton, Freeland, & Okamura, 2001).…”

The relative importance of spatial and environmental processes in distribution of benthic chironomid larvae within a large and shallow lake

“…51 environmental filtering) processes. However, development of the concept has resulted in a 52 much more continuous approach of metacommunity organization characteristics (Gravel et Applying the metacommunity framework, Grönroos et al (2013) and Heino (2013a,b) argued 80 that the relative role of spatial and local environmental factors in assembly of local 81 communities of aquatic invertebrates depend not only on the spatial scale scanned but also on 82 species traits, especially on dispersal mode. In line with the conclusions of the above studies, 83 it could be supposed that fine-scale (e.g.…”

The Interplay Between Landscape Structure and Biotic Interactions

“…Yet variation in dispersal rate among species in a metacommunity-a key component of metacommunity dynamics-can result from species' traits or structural aspects of the landscape (e.g., distance between patches, matrix structure, and arrangement of patches) [46]. Whereas metacommunity models include general variation in dispersal, few investigations (e.g., [47]) explore how dispersal is affected by both functional connectivity, i.e., the role of species traits and their interaction with the landscape, and structural connectivity, i.e., spatial configuration of landscape features [48].…”