Transferable catchment-lake framework for food web stability in shallow lowland lakes under climate and land use...

Shallow lowland lakes typically host simple food webs that are highly responsive to nutrient inputs driven by both climate change and land use. To mechanistically evaluate these coupled impacts, we integrated the PNDP model for simulating catchment-scale nutrient export with the WET model for in-lake food web dynamics. Model outputs were used to compute a local stability index (s) based on food web interactions. Simulated nutrient loading gradients yielded s-values between 0.62 and 0.65, indicating local stability below the critical threshold (s = 1.0), with increasing s indicating reduced local stability and thus a weakening of resilience under higher nutrient enrichment. Under projected scenarios, the 2030s showed a slight increase in local stability (lower s; mean s = 0.63) due to reduced nitrogen loading (NLoad) and enhanced top-down control, whereas the 2050s exhibited reduced stability (mean s = 0.65), driven by a 1.91 °C rise in temperature and a phosphorus loading (PLoad) increase to 3.91 mg/m²/day. Partial Least Squares Regression (PLSR) revealed that temperature exerted the strongest influence on s (total effect +0.42), followed by PLoad. Land use patterns had contrasting effects: residential areas expansion indirectly destabilized food webs (+0.23), whereas paddy lands exerted a buffering effect (-0.25). These findings underscore the compounded destabilizing effects of warming and eutrophication, and highlight the utility of integrated modeling for supporting resilience-oriented lake management.