Context dependency in biodiversity patterns of central German stream metacommunities

Abstract

Summary Context dependency is an emerging topic that is challenging our understanding of the factors shaping biodiversity in metacommunities. River networks and other dendritic systems provide unique systems for examining variation in the processes shaping biodiversity between different metacommunities. We examined biodiversity patterns in five benthic invertebrate data sets, from two catchments in central Germany, with the aim of exploring context dependency in these systems. We used variance partitioning to disentangle the variation explained in three biodiversity metrics: taxonomic richness, Simpson's diversity and local contribution to beta diversity (LCBD; a measure of the uniqueness of a site). As explanatory variables, we used proxies of network position (i.e. catchment size and altitude) and habitat conditions. Contrary to our expectation, we found no evidence of a decline in LCBD downstream in our study. Local habitat conditions and catchment land use played a much stronger role than catchment size and altitude in explaining variation in the three biodiversity metrics. Observed patterns were highly variable between different data sets in our study. These findings suggest that factors shaping biodiversity patterns in these systems are highly context dependent and less related to their position along the river network than local habitat conditions. Given the clear context dependency between data sets, we urge researchers to focus on disentangling the factors driving the high levels of variability between individual systems through the study of a number of replicate, rather than single, metacommunities.

Experimentally disentangling the influence of dispersal and habitat filtering on benthic invertebrate community structure

“…Network structure and dispersal can interact with larger scale habitat variables like drying and elevation Bogan, Boersma, & Lytle, 2013;Canedo-Arguelles et al, 2015;Leigh & Datry, 2017) and that these interactions can be highly context dependent (Heino, Gr€ onroos, Soininen, et al, 2012;Tonkin, Heino, Sundermann, Haase, & J€ ahnig, 2016;Schmera et al 2017). Even on smaller spatial scales like the stream reach scale, natural complexity and habitat variability can directly affect the process of macroinvertebrate dispersal (Brooks, Wolfenden, Downes, & Lancaster, 2017).…”

Knitting patterns of biodiversity, range size and body size in aquatic beetle faunas: significant relationships but slightly divergent drivers

“…Accordingly, we first Hellinger-transformed province-by-species matrix (Legendre & Gallagher, 2001) and subsequently calculated the total beta diversity (BD total) (i.e. Recent applications of the LCBD approach are described by Tonkin et al (2016) the contribution of each site to total variation).…”

Global patterns in the metacommunity structuring of lake macrophytes: regional variations and driving factors

“…Other lake studies have found that biological assemblages with passive dispersal mode or large body size are more structured by spatial processes than local environmental conditions (Beisner et al 2006; De Bie et al 2012; Padial et al 2014). However, a large amount of variation is present in the findings depending on the studied biological group, study region, and spatial extent, leading to context dependency in the patterns detected (Alahuhta and Heino 2013; Tonkin et al 2016). One biological group showing context dependency has been aquatic macrophytes, many of which are distributed around the world due to efficient dispersal abilities and colonization strategies (Santamaría 2002; Chambers et al 2008).…”