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This study develops a mathematical framework to understand how infectious diseases affect food chain stability when species interactions depend on both population size and spatial distance. The researchers found that disease at middle trophic levels causes population oscillations through destabilization, while disease at top predator levels can lead to species extinction, with the strength of spatial coupling determining critical thresholds between these outcomes. The position where disease enters the food chain fundamentally alters ecosystem dynamics in predictable ways.
Why it matters
This framework could help predict ecosystem collapse or recovery in response to emerging infectious diseases in wildlife populations. Understanding these dynamics is crucial for conservation management and anticipating cascading effects when disease outbreaks occur at different levels of food webs.
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arXiv:2607.18434v2 Announce Type: replace
Abstract: Ecological communities are shaped by the interplay between trophic interactions and infectious disease, yet how spatially mediated interactions influence disease-driven ecosystem dynamics remains poorly understood. Here, we develop a gravity-based eco-epidemiological framework for a tri-trophic food chain in which trophic interaction depends on species abundances and effective interaction distance. The disease-free food chain system supports a stable coexistence equilibrium, providing a baseline for investigating disease-induced ecological transitions. Introducing infection at the intermediate trophic level destabilizes this equilibrium through a Hopf bifurcation, leading to sustained oscillations, whereas infection at the top predator level results in a qualitatively different transition from persistence to extinction. By systematically varying the gravity coupling strength, we show that gravity-mediated trophic interactions regulate the thresholds separating these ecological regimes, while the trophic position of infection determines the nature of the transition. Together, these findings establish a unified framework for understanding how spatially mediated trophic interactions and infectious disease jointly govern ecosystem stability, providing new insights into disease-driven dynamics in ecological communities.
Source: Gravity-Driven Eco-Epidemiological Dynamics in Tri-Trophic Food Chains