Data from: Fish modulate how connectivity and local factors shape food webs of permanent ponds

The propagation of metacommunity processes through local trophic
interactions has seldom been explored, particularly in empirical studies.
This study examines how local environmental conditions and metacommunity
connectivity influence community assembly and food web structure in
pondscapes. We survey taxonomic richness, abundance, and isotopic niches
across multiple assemblage, including zooplankton, macroinvertebrates,
tadpoles, turtles, and fish. A gradient in the composition of the pond
community representing the dominance of fish or other taxa and another
gradient associated with macroinvertebrate diversity were evidenced. Pond
size and connectivity promoted fish richness and abundance, representing
the main path through which metacommunity processes cascade down within
communities, determining the assembly of the whole system. The dominance
of fish was associated with large food chains, a reduction in the width of
the food web width, and the trophic spacing. Local conditions such as
macrophyte coverage and pond size modulate the strength of these fish
effects, determining the representation of macroinvertebrates and
amphibians. Consequently, the effects of pond connectivity on community
assembly may result as a consequence of isolation's influence on top
predators' performance, rather than by the direct effect of dispersal
on different species, as is usually assumed. Metacommunity theory has
highlighted the direct effect of dispersal on species performance and
diversity. Our study highlights the indirect influence of landscape
mediated by keystone species, which connect metacommunity dispersal with
local community processes more than previously thought.