Data from: Connectivity loss in experimental pond networks leads to biodiversity loss in microbial metacommunities

Habitat fragmentation is among the most important global threats to
biodiversity, however, the direct effects of its components including
connectivity loss are largely unknown and still mostly inferred based on
indirect evidence. Our understanding of these drivers is especially
limited in microbial communities. Here, by conducting a four-month outdoor
experiment with artificial pond (mesocosm) metacommunities, we studied the
effects of connectivity loss on planktonic microorganisms, primarily
focusing on pro- and microeukaryotes. Connectivity loss was simulated by
stopping the dispersal among local habitats after an initial period with
dispersal. Keeping the habitat amount constant and the abiotic environment
homogeneous. allowed us to track the direct effects of the process of
connectivity loss. We found that connectivity loss led to higher levels of
extinction and a decrease in both local and regional diversity in
microeukaryotes. In contrast, diversity patterns of prokaryotes remained
largely unaffected, with some indications of extinction debt. Connectivity
loss also led to lower evenness in microeukaryotes, likely through changes
in biotic interactions with zooplankton grazers. Our results imply that
connectivity loss can directly translate into species losses in
communities and highlight the importance of conserving habitat networks
with sufficient dispersal among local habitats.