Resource predictability modulates spatial-use networks in an endangered scavenger species

Area of Science:

• Ecology
• Conservation Biology
• Movement Ecology

Background:

• Human-induced changes in resource availability significantly impact wildlife foraging strategies.
• European environmental policies, including the Landfill Waste Directive and Circular Economy Action Plan, will reduce predictable anthropogenic food subsidies (PAFS) by closing landfills.
• Obligate avian scavengers, like the Egyptian vulture (Neophron percnopterus), are particularly vulnerable to these changes, potentially requiring significant behavioral and spatial adjustments.

Purpose of the Study:

• To examine the consequences of reduced landfill availability on the foraging patterns of Egyptian vultures in the Iberian Peninsula.
• To predict how changes in predictable anthropogenic food subsidies (PAFS) will affect the movement and spatial use of both breeding and non-breeding Egyptian vultures.
• To assess the vulnerability of Egyptian vulture foraging networks to the loss of key resources.

Main Methods:

• Tracking of 16 Egyptian vultures (breeders and non-breeders) from 2018-2021.
• Application of spatial-use and spatial-network modeling to analyze landscape connectivity based on movement patterns.
• Simulation of future scenarios involving the loss of PAFS to predict changes in vulture movement patterns.

Main Results:

• Significant differences observed in foraging strategies between non-breeders (more dispersal movements) and breeders.
• Vulture foraging networks were found to be vulnerable to the removal of landfill sites, a crucial predictable resource.
• Perturbation analysis revealed varied responses to the reduction of other predictable resources, with a predicted increase in livestock carcass utilization in the absence of landfills.

Conclusions:

• Environmental policies should consider designating areas where livestock carcasses can remain in the wild to support scavenger populations facing reduced food subsidies from landfill closures.
• Spatial network approaches are effective tools for understanding movement ecology and predicting behavioral responses of animal species.
• Applying these approaches is crucial for the conservation of endangered species, especially within evolving human-dominated landscapes.