Forest loss is a major environmental threat in the Anthropocene.
Repercussions are rarely localised and often impacts adjacent
ecosystems. For example, forest loss is generally detrimental to
freshwater biodiversity. There are however, some uncertainties about its
effects on food webs and ecosystem functioning. We tracked changes in
the food webs of four tropical stream catchments (two time points
separated by a ~20-year interval) affected by varying
degrees of forest loss. Our data show that the proportion of assimilated
terrestrial organic matter (allochthony) remained largely invariant, but
changes in food chain lengths inferred from the trophic positions of
apex predators (TP) differed between catchments. Here, we found that
higher rates of forest loss resulted in more significant reductions in
TP. We speculate that the mechanisms involved are unrelated to
diminished terrestrial subsidies as allochthony values were low
(~7%) and did not shift in response to forest loss.