Ecological data for: Subsidy accessibility drives asymmetric food web responses

Global change is fundamentally altering flows of natural and anthropogenic
subsidies across space and time. After a pointed call for research on
subsidies in the 1990s, an industry of empirical work has documented the
ubiquitous role subsidies play in ecosystem structure, stability and
function. Here, we argue that physical constraints (e.g., water
temperature) and species traits can govern a species’ accessibility to
resource subsidies, which has been largely overlooked in the subsidy
literature. We examined the input of a high quality, point-source
anthropogenic subsidy (aquaculture feed) into a recipient freshwater lake
food web. By using a combined bio-tracer approach, we detect a gradient in
accessibility of the anthropogenic subsidy within the surrounding food web
driven by the thermal preferences of three constituent species,
effectively rewiring the recipient lake food web. Since aquaculture is
predicted to increase significantly in coming decades to support growing
human populations, and global change is altering temperature regimes, then
this form of food web alteration may be expected to occur frequently. We
argue that subsidy accessibility is a key characteristic of recipient food
web interactions that must be considered when trying to understand the
impacts of subsidies on ecosystem stability and function under continued
global change.