Conservation of the Cinereous Vulture Aegypius monachus in Spain (1966-2011): a bibliometric review of threats, research and adaptive management

Detecting and quantifying threats and researching and implementing management actions are key to improving the conservation status of endangered species. Bibliometric analysis can constitute a useful tool for the evaluation of such questions from a long-term perspective. Taking as a case study the Cinereous Vulture Aegypius monachus in Spain, we tested relationships between population dynamics, research efforts, existing threats and conservation milestones. The population growth of the species (from 206 pairs in 1976 to 2,068 in 2011) was parallelled by the increase in the total number of publications, the number of articles in SCI journals and the number of published works dealing with aspects of conservation, threats and management. These results are discussed in terms of cause-effect relationships taking into account that the influence of other non-mutually exclusive factors could also probably explain such associations. Similarly, we analysed the trend of the Cinereous Vulture breeding population with respect to different threats and indices of food availability, obtaining a positive correlation with the increase in big-game hunting bags in Spain. With respect to conservation milestones, we concluded that the current situation is positive in terms of the protection of the species and its habitat, with the situation in relation to food availability being unclear. Finally, we reviewed the main conservation actions that have been taken for the species in Spain and how these have been progressively modified based on new scientific and technical evidence, as an example of adaptive management applied to conservatio

How to fit the distribution of apex scavengers into land-abandonment scenarios? The Cinereous vulture in the Mediterranean biome

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.Spanish Ministry of Economy and Competitiveness, Grant/Award Number: BES-2014-070597Juan de la Cierva Incorporación, Grant/Award Number: IJCI-2014-20744;Programa Viçent Mut of Govern Balear, Spain, Grant/Award Number: PD/039/2017;Consejería de Innovación, Ciencia y Empleo, Junta de Andalucía, Grant/Award Number: RNM-1925;MINECO/FEDER EU, Grant/Award Number: CGL2015-66966-C2-1-2-R;Severo Ochoa Excellence Award from the Spanish Ministry of Economy and Competitiveness, Grant/Award Number: SEV-2012-0262;CEAUL; FCT—Fundação para a Ciência e a Tecnologia, Portugal, Grant/Award Number: UID/MAT/00006/201

Minimising Mortality in Endangered Raptors Due to Power Lines: The Importance of Spatial Aggregation to Optimize the Application of Mitigation Measures

Electrocution by power lines is one of the main causes of non-natural mortality in birds of prey. In an area in central Spain, we surveyed 6304 pylons from 333 power lines to determine electrocution rates, environmental and design factors that may influence electrocution and the efficacy of mitigation measures used to minimise electrocution cases. A total of 952 electrocuted raptors, representing 14 different species, were observed. Electrocuted raptors were concentrated in certain areas and the environmental factors associated with increased electrocution events were: greater numbers of prey animals; greater vegetation cover; and shorter distance to roads. The structural elements associated with electrocutions were shorter strings of insulators, one or more phases over the crossarm, cross-shaped design and pylon function. Of the 952 carcasses found, 148 were eagles, including golden eagle (Aquila chrysaetos), Spanish imperial eagle (Aquila adalberti) and Bonelli's eagle (Aquila fasciata). Electrocuted eagles were clustered in smaller areas than other electrocuted raptors. The factors associated with increased eagle electrocution events were: pylons function, shorter strings of insulators, higher slopes surrounding the pylon, and more numerous potential prey animals. Pylons with increased string of insulators had lower raptor electrocution rates than unimproved pylons, although this technique was unsuccessful for eagles. Pylons with cable insulation showed higher electrocution rates than unimproved pylons, both for raptors and eagles, despite this is the most widely used and recommended mitigation measure in several countries. To optimize the application of mitigation measures, our results recommend the substitution of pin-type insulators to suspended ones and elongating the strings of insulators

Carrion Availability in Space and Time

Introduction Availability of carrion to scavengers is a central issue in carrion ecology and management, and is crucial for understanding the evolution of scavenging behaviour. Compared to live animals, their carcasses are relatively unpredictable in space and time in natural conditions, with a few exceptions (see below, especially Sect. “Carrion Exchange at the Terrestrial-Aquatic Interface”). Carrion is also an ephemeral food resource due to the action of a plethora of consumers, from microorganisms to large vertebrates, as well as to desiccation (i.e., loss of water content; DeVault et al. 2003; Beasley et al. 2012; Barton et al. 2013; Moleón et al. 2014). With a focus on vertebrate carcasses, here we give an overview of (a) the causes that produce carrion, (b) the rate of carrion production, (c) the factors affecting carrion quality, and (d) the distribution of carrion in space and time, both in terrestrial and aquatic environments (including their interface). In this chapter, we will focus on naturally produced carrion, whereas non-natural causes of animal mortality are described in chapter “Human-Mediated Carrion: Effects on Ecological Processes”. However, throughout this chapter we also refer to extensive livestock carrion, because in the absence of strong restrictions such as those imposed in the European Community after the bovine spongiform encephalopathy crisis (Donázar et al. 2009; Margalida et al. 2010), the spatiotemporal availability of carrion of extensive livestock and wild ungulates is similar

Post-mortem volatiles of vertebrate tissue

Volatile emission during vertebrate decay is a complex process that is understood incompletely. It depends on many factors. The main factor is the metabolism of the microbial species present inside and on the vertebrate. In this review, we combine the results from studies on volatile organic compounds (VOCs) detected during this decay process and those on the biochemical formation of VOCs in order to improve our understanding of the decay process. Micro-organisms are the main producers of VOCs, which are by- or end-products of microbial metabolism. Many microbes are already present inside and on a vertebrate, and these can initiate microbial decay. In addition, micro-organisms from the environment colonize the cadaver. The composition of microbial communities is complex, and communities of different species interact with each other in succession. In comparison to the complexity of the decay process, the resulting volatile pattern does show some consistency. Therefore, the possibility of an existence of a time-dependent core volatile pattern, which could be used for applications in areas such as forensics or food science, is discussed. Possible microbial interactions that might alter the process of decay are highlighted

Conservation of the Cinereous Vulture Aegypius monachus in Spain (1966–2011): a bibliometric review of threats, research and adaptive management

Detecting and quantifying threats and researching and implementing management actions are key to improving the conservation status of endangered species. Bibliometric analysis can constitute a useful tool for the evaluation of such questions from a long-term perspective. Taking as a case study the Cinereous Vulture Aegypius monachus in Spain, we tested relationships between population dynamics, research efforts, existing threats and conservation milestones. The population growth of the species (from 206 pairs in 1976 to 2,068 in 2011) was parallelled by the increase in the total number of publications, the number of articles in SCI journals and the number of published works dealing with aspects of conservation, threats and management. These results are discussed in terms of cause-effect relationships taking into account that the influence of other non-mutually exclusive factors could also probably explain such associations. Similarly, we analysed the trend of the Cinereous Vulture breeding population with respect to different threats and indices of food availability, obtaining a positive correlation with the increase in big-game hunting bags in Spain. With respect to conservation milestones, we concluded that the current situation is positive in terms of the protection of the species and its habitat, with the situation in relation to food availability being unclear. Finally, we reviewed the main conservation actions that have been taken for the species in Spain and how these have been progressively modified based on new scientific and technical evidence, as an example of adaptive management applied to conservation

Linking sanitary and ecological requirements in the management of avian scavengers: effectiveness of fencing against mammals in supplementary feeding sites

In order to ensure that the objectives behind the conservation of biodiversity are fulfilled it is essential that policies of all stakeholders are compatible. This is the case of the application of sanitary measures for the management of animal by-products and the negative effects that such restrictions had on the population dynamics and behavioural ecology of the avian scavengers’ guild. Thus, measures that allow these species to feed and that reduce risks of disease transmission must be put into practice. This study aims to improve the technical implementation of one of the commonest tools employed in the conservation of avian scavengers: supplementary feeding stations. We evaluated the permeability of three types of fences in experimental feeding stations to determine which of the models prevent non-target species from accessing the food provided. We compared results from fenced-off feeding stations with those from random points in unfenced-off sites. The results showed that two of the models (high and low nets) were the most effective avoiding facultative mammal scavengers from gaining access into the exclosure for over two months and for 7–8 inputs of food. Avian scavengers were able to access food regardless of the type of exclosure, which did not determine the abundance of birds or the species present. The carrion consumption by non-target species can be reduced by affordable and sustainable means. We suggest proposals to optimize the management of supplementary feeding stations for threatened avian scavengers and for the design of fenced exclosures.This work was funded by the General Directorate of Wildlife and Forestry of the Ministry of Environment, Rural and Marine Affairs of Spain.Peer reviewe

Grain sowing aimed at wild rabbit Oryctolagus cuniculus L. enhancement in Mediterranean environments

Although habitat management practices focussed on the enhancement of hunting and protection of threatened species are common, the scientific validation of such practices is scarce. The wild European rabbit Oryctolagus cuniculus L.;a hunted and threatened species in its native range, is at the same time a key species for the preservation of threatened Mediterranean predators. Cereal sowing is one of the most common practices to augment the food supply of rabbits, and it is used not only by hunters but also by conservationists. At present, limited scientific information is available regarding the effectiveness of cereal sowing. To evaluate its effectiveness, we analysed data on sowing trials conducted in 125 plots, located in 14 private estates throughout central Spain, most of them with low density populations. Brush was cleared from 44 of these plots prior to sowing. Our results indicated that rabbits preferentially selected sown areas over control (unsown) areas. This selection increased in plots that represented suitable habitats for rabbits, such as pasturelands, as well as when thicket islands and natural or artificial shelters were available within the sown plots. Local enhancement of rabbit populations was also observed. These positive results were also obtained regardless of the initial habitat conditions, not only in the treatment plots but also in the surrounding area. Our recommendations can be broadly applied for managing rabbit-dependent threatened species. © 2014 Elsevier GmbH