A graph based advection framework for climate-driven species distribution

TL;DR

This paper introduces a graph-based reaction-diffusion-advection model that explicitly incorporates directional movement driven by environmental gradients, revealing its impact on species distribution and persistence in fragmented landscapes.

Contribution

It develops a novel framework integrating advection into network models, highlighting how directional movement influences species hotspots and extinction risks under climate change.

Findings

Advection creates asymmetric population flows and hotspots.

Strong advection can increase local extinction risk.

Loss of corridors disrupts directed flow, affecting species distribution.

Abstract

Climate change is reshaping species interactions and movement across fragmented landscapes. Despite this, most mathematical models assume random diffusion, overlooking the influence of directed movement. Here, we develop a graph based reaction-diffusion-advection framework explicitly incorporating directional movement induced by environmental gradients. Our results show while diffusion promotes overall population persistence across the network, advective movement induces asymmetric flows. It create population hotspots by directing individuals toward optimal niches, often associated with nodes of high in-degree. We demonstrate the interplay between advection strength and network topology in determining species persistence. Strong advection increase local extinction risk by accumulating populations toward favorable nodes. Additionally, loss of ecological corridors can disrupt directed flow within the network, thereby restricting species from favorable patches. We found that this disruption might not cause immediate extinction, rather forcing species to spread to the suboptimal patches. Our advection framework therefore efficiently captures how directional movement interacting with network topology governs species redistribution, hotspot formation, and predict extinction risk under environmental change.