Waterbird guilds function as dynamic cross-ecosystem energy vectors in unique soda pan model systems

Migratory animals play a key role in coupling ecosystems through the redistribution of energy, to date, energy transport by functional guilds has not been comprehensively quantified. Here, I present a generalized, own guild-based framework that extends established waterbird nutrient-cycling guild concepts into the energy flow across ecosystems, enabling the quantification of energy import, export and net balance mediated by waterbirds. Using long-term (1986–2017) waterbird census data from two internationally important (Ramsar-sites) intermittent soda pans in Central Europe, as simplified unique model systems. I estimated avian energy fluxes by integrating guild-specific foraging behaviour, habitat use, metabolic demand and residence time. Waterbird guilds were classified as net importers, importer–exporters or net exporters of energy based on Boros’s method. Estimated annual energy fluxes varied across several orders of magnitude, reflecting pronounced interannual variability in the studied ecosystem. Net energy import ranged widely from 574,712 to 57,022,011 kJ/ha/yr, while net energy export from 361,206 to 16,171,538 kJ/ha/yr. The net energy import consistently and significantly exceeded net energy export. Consequently, the average community-level energy balance was significantly positive (+ 51.3) regarding waterbird-mediated nutrient transport. The functional asymmetry between guilds ensures that energy import remains dominant over export regardless of species richness, fundamentally defining the ecosystem’s role as a significant energy sink in the studied system. Temporal analyses revealed significant dynamics in net energy import, whereas variation in open water area did not predict exactly energy balance. I partly reject the hypothesis that net energy import responds predictably to long-term trends in open water area, but partly confirm as it is rather depends on guild-structure dynamics. These results demonstrate that cross-ecosystem energy transport by waterbirds is governed primarily by functional guild composition and behaviour rather than habitat extent alone. The proposed framework provides a scalable tool for integrating avian-mediated energy transport into ecosystem energetics and spatial food-web theory.