Rewilding processes shape the use of Mediterranean landscapes by an avian top scavenger

P Martin-Díaz,A Cortés-Avizanda,D Serrano,J A Donázar,E Arrondo,J A Sánchez-Zapata

doi:10.1038/s41598-020-59591-2

Abstract

The Mediterranean biome has seen a great decline in its rural population. This trend has been followed by an abandonment of agricultural and livestock practices, which has provided an opportunity for rewilding to take place. Rewilding processes can modify the availability of carrion resources for avian obligate scavengers and reduce accessible open areas due to the increase of shrub and forest. We examined how changes in landscape configuration in the past five decades (1956–2011) mediate the foraging behaviour of griffon vultures. Particularly, we examined whether vultures use those areas under natural succession and with a high availability of wild ungulate carcasses. We used GPS information yielded by 30 adult griffon vultures exploiting large regions of southern Spain. We determined (a) habitat use considering land uses and food availability and (b) how tracked individuals responded to areas in different stages of rewilding. Our results showed that vultures preferentially used Mediterranean scrublands, woodlands and the agroforest Mediterranean ecosystem called dehesa, as well as areas with high food resources, namely wild ungulates in winter and a mixture of wild ungulates and livestock in summer. Due to a higher abundance of wild ungulates, vultures forage preferentially in areas with low levels of rewilding, either for being in the first stages of natural succession or for not having experienced further rewilding since the middle of the last century. Rewilding processes are expected to continue in the future affecting the scavenger guild structure and function deeply. Improved management will be essential to preserve ecological processes, ecosystem services and populations of endangered species.

Highlights

The Mediterranean biome has seen a great decline in its rural population
The Mediterranean biome has been undergoing an important decline in its rural population followed by an abandonment of agricultural land, pastures and traditional livestock practices (−15% between 1970–20105), a trend that is foreseen to escalate in the future[9,10]
Our results show that griffon vultures concentrate an important part of their foraging activities in rewilding areas where carcasses of wild ungulates have become the main trophic resource available

Summary

Introduction

The Mediterranean biome has seen a great decline in its rural population. This trend has been followed by an abandonment of agricultural and livestock practices, which has provided an opportunity for rewilding to take place. Homogenisation, overgrazing and a loss of genetic diversity and biodiversity are well-known consequences of agricultural intensification[6,7], less focus has been given to the consequences of traditional land use changes as well as the reduction of human control on landscapes[5,8] Within this scenario, the Mediterranean biome has been undergoing an important decline in its rural population followed by an abandonment of agricultural land, pastures and traditional livestock practices (−15% between 1970–20105), a trend that is foreseen to escalate in the future[9,10]. Rewilding implies a densification of the vegetation, so vultures might have more difficulty in finding and accessing carcasses[20]

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Conclusion