Data from: Intraspecific niche variation drives abundance-occupancy relationships in freshwater fish communities

A positive relationship between occupancy and average local abundance of
species is found in a variety of taxa, yet the mechanisms driving this
association between abundance and occupancy are still enigmatic. Here we
show that freshwater fishes exhibit a positive abundance-occupancy
relationship across 125 Swedish lakes. For a subset of 9 species from 11
lakes, we estimated species-specific diet breadth from stable isotopes,
within-lake habitat breadth from catch data for littoral and pelagic nets,
adaptive potential from genetic diversity, abiotic niche position, and
dispersal capacity. Average local abundance was mainly positively
associated with both within-lake habitat and diet breadth, that is,
species with larger intraspecific variation in niche space had higher
abundances. No measure was a good predictor of occupancy, indicating that
occupancy may be more directly related to abundance or abiotic conditions
than to niche breadth per se. This study suggests a link between
intraspecific niche variation and a positive abundance-occupancy
relationship and implies that management of freshwater fish communities,
whether to conserve threatened or control invasive species, should
initially be aimed at niche processes.