Epizootics and sanitary regulations drive long-term changes in fledgling body condition of a threatened vulture

Abstract

Epizootics and deliberate changes in policies affecting the environment may affect large groups of species and the functioning of entire ecosystems. Although these effects often overlap in time, their simultaneous effect is rarely examined despite their importance as causes of current biodiversity loss. Here, based on the monitoring of an Egyptian vulture (Neophron percnopterus) population over thirty-three years , we increase our knowledge about the effects of anthropogenic-induced changes in food availability, both direct (sanitary policies limiting livestock carcass disposal) and indirect (a wild rabbit epizootic), on brood size and body condition of fledglings at nests. We compared the body mass of fledglings of broods with one chick (Single) and two chicks (within which we distinguished First and Second-hatched). The mass of Second-hatched chicks decreased after the plummet in rabbit populations (in the year 1990) and the regulations limiting carcass disposal ( 2005), reaching minimum values during the period with lowest food availability (i.e. 2005-2013). Recent sanitary legislation allowing carcass disposal by farmers coincides with a slight recovery in the observed body masses. Overall, this study shows that environmental changes of disparate origin can have synergistic effects on individual condition. Conservation of endangered vultures will require multi-targeted conservation plans aimed at ensuring nutritional requirements, in addition to detailed long-term monitoring, in order to detect obscure/ masked drivers that affect body condition of fledglings.

Social actors’ perceptions of wildlife: Insights for the conservation of species in Mediterranean protected areas

“…Former research also found that the perception of a species as emblematic can often determine the focus of scientific activities (Wilson et al 2007) and environmental education programs (Martín-López et al 2009;Kim et al 2014;Jarić et al 2019;Lozano et al 2019). This finding is supported by our research since Egyptian and griffon vultures, two of the most mentioned species (mentioned by 25% and 37% of respondents, respectively), have been the main focus of long-term monitoring and GPS-tagged research projects in Bardenas Reales Natural Park (Cortés-Avizanda et al 2015, 2018Sanz-Aguilar et al 2017;Arrondo et al 2020;Donázar et al 2020). Furthermore, the wild rabbit which was mentioned the most (by 47% of respondents) is one of the species that has attracted a large amount of scientific interest because of its role as a keystone species in the Mediterranean biome (Delibes-Mateos et al 2007;Cortés-Avizanda et al 2015).…”

“…This protected area has no human settlements as only traditional agriculture and livestock keeping are permitted (see details in Cortés-Avizanda et al 2009, 2018. This contrasts with surrounding areas that hold dense human settlements and intensive farming areas (Cortés-Avizanda et al 2009Arrondo et al 2020). Interestingly, this area constitutes a singular region because it is the breeding habitat of several species representative of the Mediterranean Basin.…”

Phenotypic and environmental correlates of natal dispersal in a long-lived territorial vulture

“…Egyptian vulture populations suffered a dramatic human-induced decline in the past that made the species disappear from many locations of Spain and France 44 , 48 . Currently, some of the threatening causes have subsided, others continue operating, and new conservation challenges are arising, with the result that the species is recovering in certain areas 47 , 48 , 83 while continues to decline in others 84 . In this context, relevant questions are how natal dispersal strategies may contribute to local population persistence and dynamics.…”

Genetic signatures of population bottlenecks, relatedness, and inbreeding highlight recent and novel conservation concerns in the Egyptian vulture

“…The nests were accessed by climbing when nestlings were feathered (at ages of about 50 days) but without risk of leaving the nests. The clutch size in this species is of two eggs, but in a proportion of nests only one nestling survives, mostly the first-hatched nestling ( Donázar et al, 2020 ). Therefore, sampled nestlings can correspond to the single nestling in the nest (brood size = 1) or two siblings in the same nest (brood size = 2).…”