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International audience ; Among vertebrates, specialization in scavenging has appeared only in "true" vultures, which usually base their diet almost exclusively on carcasses of medium and large-sized mammals, whereas all other scavengers rely on broader ranges of prey. The availability of food for scavengers in Western Europe has not been limited during recent decades permitting the existence and growth of huge vulture populations. From 2000 onwards, however, EU sanitary legislation has progressively limited the abandonment of dead animals in the field resulting in a sudden reduction of food availability with unknown ecological and conservation consequences. Here, we examine the dietary response of a tandem of carrion eaters, the griffon vulture () and the Egyptian vulture (), showing different degrees of dietary specialization. Our results showed that after the reduction in numbers of supplementary feeding stations (vulture restaurants) the niche breadth of the griffon vulture has broadened and now includes significant amounts of wild rabbits () and garbage. The diet of the Egyptian vulture, on the contrary, did not vary substantially. The diet overlap showed patterns probably conditioned by interspecific competition and the progressive exploitation of unpredictable carcasses. On a short-term scale, consequences for smaller scavengers could be negative due to the monopolization of resources by the dominant and much more abundant griffon vulture, however in the long-term all guild species would benefit from the exploitation of unpredictable carcasses, which could enhance the possibilities of coexistence.

Current European sanitary laws are promoting the concentration of domestic livestock carcasses in lim- ited locations called 'vulture restaurants' or supplementary feeding stations in order to safeguard human health. However, this type of food concentration could lead to monopolization by a few, large dominant species. Management guidelines are urgently needed to ensure that potentially less competitive and more endangered scavengers can also benefit from this resource, considering that once abundant car- casses are now absent from the field. Here, we assess factors affecting the abundance of six avian scav- enger species at 17 feeding stations in northern Spain, considering aspects such as carrion availability, physiographic features, humanization, presence of heterospecifics and densities of scavengers during both winter and summer seasons. Results indicate that conditions for interspecific facilitatory processes are possible at low numbers (<100 individuals) of griffon vultures (Gyps fulvus). Otherwise, the other avian scavengers are excluded. In a few cases, spatio-temporal patterns of segregation become apparent. Differences in the size of carcasses supplied to feeding stations as well as the local characteristics influ- ence the balance of species at these points and, therefore, how species of conservation concern use feed- ing stations. Future legislation should encourage the opening of numerous feeding stations supplied with low quantities of food to mimic the original condition of temporal and spatial unpredictability of car- casses and to maintain ecological relationships within the scavenger guild. ; Peer reviewed

Under a Creative Commons license. ; 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 (1986–2018), 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. ; This research was funded by the Comunidad de Bardenas Reales de Navarra and the Projects CGL2015-66966-C2-1-2-R and RTI2018-099609-B-C21 (Spanish Ministry of Economy and Competitiveness and EU/FEDER), AAEE123/2017 (accions especials d'R+D Conselleria d'Innovació, Recerca I Turisme, Govern Balear). ACA was supported by a Post-Doctoral contract Juan de la Cierva Incorporación (IJCI-2014-20744) from Ministerio de Economía y Competitividad, Spain and a post-doctoral contract Programa Viçent Mut of Govern Balear, Spain (PD/039/2017). EA was supported by La Caixa-Severo Ochoa International PhD Program 2015. ; Peer reviewed

Political boundaries may represent ecological barriers due to differences in wildlife management policies. In the European Union, it might be expected that these differences should be highly diluted, because all countries have to comply with common directives issued by the European Commission. However, the subsidiarity principle may lead to the uneven uptake of European Union regulations, which can impact on biodiversity conservation due to unequal legislation in neighboring countries, particularly in the case of highly mobile organisms. Here we address this issue, by analyzing how EU regulations issued in response to the Bovine Spongiform Encephalopathy (BSE) crisis differentially affected vulture conservation in Portugal and Spain. Taking advantage of the intensive GPS-tracking of 60 griffon (Gyps fulvus) and 11 cinereous vultures (Aegypius monachus) from Spain, we found that the Spanish-Portuguese border acts as a quasi-impermeable barrier. In fact, there was an abrupt decline in the number of vulture locations across the Spanish-Portuguese border, with modelling showing that this was unlikely to be related to differences in land cover or topography. Instead, the pattern found was likely due to differences in trophic resource availability, namely carcasses from extensive livestock husbandry, resulting from the differential application of European sanitary legislation regarding the mandatory removal of dead livestock from the field. Overall, our results should be seen as a warning signal to policy makers and conservation managers, highlighting the need for a stronger integration of sanitary and environmental policies at the European level. ; This research was funded by the Consejeria de economia innovacion ciencia y empleo Junta de Andalucia (Proyecto de Excelencia 2012 RNM-1925) (Junta de Andalucía), Comunidad de Bardenas Reales de Navarra (Convenios EBD-CSIC 2014-2017), ; MInisterio de Economia, Industria y competitividad (Projecto CGL2015-66966-C2-1- 2-R) (Spanish Ministry of Economy and Competitiveness and ...

Migrant populations must cope not only with environmental changes in different biomes, but also with the continuous constraints imposed by human-induced changes through landscape transformation and resource patchiness. Theoretical studies suggest that changes in food distribution can promote changes in the social arrangement of individuals without apparent adaptive value. Empirical research on this subject has only been performed at reduced geographical scales and/or for single species. However, the relative contribution of food patchiness and predictability, both in space and time, to abundance and sociality can vary among species, depending on their degree of flexibility. ; This work was supported by the project CGL2004-00270 of Spanish Government. ; Peer reviewed

Aim Farmland abandonment or "ecological rewilding" shapes species distribution and ecological process ultimately affecting the biodiversity and functionality of ecosystems. Land abandonment predictions based on alternative future socioeconomic scenarios allow foretell the future of biota in Europe. From here, we predict how these forecasts may affect large‐scale distribution of the Cinereous vulture (Aegypius monachus), an apex scavenger closely linked to Mediterranean agro‐grazing systems. Location Iberian Peninsula. Methods Firstly, we modelled nest‐site and foraging habitat selection in relation to variables quantifying physiography, trophic resources and human disturbance. Secondly, we evaluate to what extent land abandonment may affect the life traits of the species and finally we determined how potential future distribution of the species would vary according to asymmetric socioeconomic land‐abandonment predictions for year 2040. Results Cinereous vultures selected breeding areas with steep slopes and low human presence whereas foraging areas are characterized by high abundance of European rabbits (Oryctolagus cuniculus) and wild ungulates. Liberalization of the Common Agricultural Policy (CAP) could potentially transform positively 66% of the current nesting habitat, favouring the recovery of mature forest. Contrarily, land abandonment would negatively affect the 63% of the current foraging habitat reducing the availability of preferred food resources (wild European rabbit). On the other hand, the maintenance of the CAP would determine lower frequencies (24%–22%) of nesting and foraging habitat change. Main conclusions Land abandonment may result into opposite effects on the focal species because of the increase in nesting habitats and wild ungulates populations and, on the other hand, lower availability of open areas with poorer densities of European rabbits. Land‐abandonment models' scenarios are still coarse‐grained; the apparition of new human uses in natural areas may take place at small‐sized and ...

Aim: Farmland abandonment or "ecological rewilding" shapes species distribution and ecological process ultimately affecting the biodiversity and functionality of ecosystems. Land abandonment predictions based on alternative future socioeconomic scenarios allow foretell the future of biota in Europe. From here, we predict how these forecasts may affect large-scale distribution of the Cinereous vulture (Aegypius monachus), an apex scavenger closely linked to Mediterranean agro-grazing systems. Location: Iberian Peninsula. Methods: Firstly, we modelled nest-site and foraging habitat selection in relation to variables quantifying physiography, trophic resources and human disturbance. Secondly, we evaluate to what extent land abandonment may affect the life traits of the species and finally we determined how potential future distribution of the species would vary according to asymmetric socioeconomic land-abandonment predictions for year 2040. Results: Cinereous vultures selected breeding areas with steep slopes and low human presence whereas foraging areas are characterized by high abundance of European rabbits (Oryctolagus cuniculus) and wild ungulates. Liberalization of the Common Agricultural Policy (CAP) could potentially transform positively 66% of the current nesting habitat, favouring the recovery of mature forest. Contrarily, land abandonment would negatively affect the 63% of the current foraging habitat reducing the availability of preferred food resources (wild European rabbit). On the other hand, the maintenance of the CAP would determine lower frequencies (24%–22%) of nesting and foraging habitat change. Main conclusions: Land abandonment may result into opposite effects on the focal species because of the increase in nesting habitats and wild ungulates populations and, on the other hand, lower availability of open areas with poorer densities of European rabbits. Land-abandonment models' scenarios are still coarse-grained; the apparition of new human uses in natural areas may take place at small-sized and medium-sized scales, ultimately adding complexity to the prediction on the future of biota and ecosystems.

Natal dispersal, the movement between the birth and the first breeding site, has been rarely studied in long-lived territorial birds with a long-lasting pre-breeding stage. Here we benefited from the longterm monitoring programs of six populations of Egyptian vultures (Neophron percnopterus) from Spain and France to study how the rearing environment determines dispersal. For 124 vultures, we recorded a median dispersal distance of 48 km (range 0–656 km). Linear models were used to assess the effect of population and individual traits on dispersal distance at two spatial scales. Dispersal distances were inversely related to vulture density in the natal population, suggesting that birds perceive the abundance of conspecifics as a signal of habitat quality. This was particularly true for declining populations, so increasing levels of opportunistic philopatry seemed to arise in high density contexts as a consequence of vacancies created by human-induced adult mortality. Females dispersed further than males, but males were more sensitive to the social environment, indicating different dispersal tactics. Both sexes were affected by different individual attributes simultaneously and interactively with this social context. These results highlight that complex phenotype-by-environment interactions should be considered for advancing our understanding of dispersal dynamics in long-lived organisms. ; Funds were partially provided by Diputación General de Aragón, Junta de Andalucía, Comunidad de Bardenas and Projects CGL2009-12753-C02-02, CGL2009-12753-C02-01/BOS and CGL2010-15726 of Spanish Ministerio of Economía y Competitividad. ACA was supported by a contract Juan de la Cierva Incorporación (IJCI-2014-20744; Ministerio de Economía y Competitividad, Spain) and a Post-Doc contract Programa Viçent Mut of Govern Balear, Spain (PD/039/2017). EA was supported by La Caixa-Severo Ochoa International PhD Program 2015, JM was supported by a Basque Government predoctoral fellowship PRE_2018_2_0112 (2017). ; Peer reviewed

Natal dispersal, the movement between the birth and the first breeding site, has been rarely studied in long-lived territorial birds with a long-lasting pre-breeding stage. Here we benefited from the long-term monitoring programs of six populations of Egyptian vultures (Neophron percnopterus) from Spain and France to study how the rearing environment determines dispersal. For 124 vultures, we recorded a median dispersal distance of 48 km (range 0–656 km). Linear models were used to assess the effect of population and individual traits on dispersal distance at two spatial scales. Dispersal distances were inversely related to vulture density in the natal population, suggesting that birds perceive the abundance of conspecifics as a signal of habitat quality. This was particularly true for declining populations, so increasing levels of opportunistic philopatry seemed to arise in high density contexts as a consequence of vacancies created by human-induced adult mortality. Females dispersed further than males, but males were more sensitive to the social environment, indicating different dispersal tactics. Both sexes were affected by different individual attributes simultaneously and interactively with this social context. These results highlight that complex phenotype-by-environment interactions should be considered for advancing our understanding of dispersal dynamics in long-lived organisms. ; Funds were partially provided by Diputación General de Aragón, Junta de Andalucía, Comunidad de Bardenas and Projects CGL2009-12753-C02-02, CGL2009-12753-C02-01/BOS and CGL2010-15726 of Spanish Ministerio of Economía y Competitividad. ACA was supported by a contract Juan de la Cierva Incorporación (IJCI-2014-20744; Ministerio de Economía y Competitividad, Spain) and a Post-Doc contract Programa Viçent Mut of Govern Balear, Spain (PD/039/2017). EA was supported by La Caixa-Severo Ochoa International PhD Program 2015, JM was supported by a Basque Government predoctoral fellowship PRE_2018_2_0112 (2017). ; Peer reviewed