Data from: Complex interaction of dendritic connectivity and hierarchical patch size on biodiversity in river-like landscapes

Habitat fragmentation and land use changes are causing major biodiversity
losses. Connectivity of the landscape or environmental conditions alone
can shape biodiversity patterns. In nature, however, local habitat
characteristics are often intrinsically linked to a specific connectivity.
Such a link is evident in riverine ecosystems, where hierarchical
dendritic structures command related scaling on habitat capacity. We
experimentally disentangled the effect of local habitat capacity (i.e.,
the patch size) and dendritic connectivity on biodiversity in aquatic
microcosm metacommunities by suitably arranging patch sizes within
river-like networks. Overall, more connected communities that occupy a
central position in the network exhibited higher species richness,
irrespective of patch size arrangement. High regional evenness in
community composition was found only in landscapes preserving
geomorphological scaling properties of patch sizes. In these landscapes,
some of the rarer species sustained regionally more abundant populations
compared to landscapes with homogeneous patch size or landscapes with
spatially uncorrelated patch size. Our analysis suggests that altering the
natural link between dendritic connectivity and patch size strongly
affects community composition and population persistence at multiple
scales. The experimental results are demonstrating a principle that can be
tested in theoretical metacommunity models and eventually be projected to
real riverine ecosystems.