Avian scavengers' contributions to people: the cultural dimension of wildlife-based tourism

Scavengers provide significant nature's contributions to people (NCP), including disease control through carcass removal, but their non-material NCP are rarely considered. For the first time, we assess the extent and value of the NCP provided by European avian scavengers through a scavenger-based tourism at Pyrenean supplementary feeding sites (SFS). Using a two-step cluster analysis, two different types of visitor were identified (specialist avian scavenger-watchers and generalist nature-lovers) at those SFS offering recreational experiences (n = 20, i.e. birdwatching, educational, or photographic activities). Most visitors (85%) perceived avian scavengers as beneficial NCP providers, associating this guild with non-material NCP (mostly supporting identities), followed by regulating and maintenance of options NCP (<1%). Our findings help to characterize the type of people who participate in scavenger related recreation and to identify and value their perceptions of avian scavengers. There has not been much previous research on positive human-wildlife interactions, even though ignoring people emotional bonds with nature can be perilous for biodiversity conservation.FundingThis study was funded by the Spanish Ministry of Economy, Industryand Competitiveness (project CGL2015-66966-C2-2-R), Ministry ofScience, Innovation and Universities (project RTI2018-099609-B-C22),and European Regional Development Fund (ERDF) through theINTERREG V - A - España - Francia - Andorra (POCTEFA 2014 - 2020program, project ECOGYP EFA 089/15). RGJ was supported by a pre-doctoral grant (FPI/BES-2016-077510) granted by the Spanish Ministryof Economy and Competitiveness. JMPG was supported by a SpanishMinistry of Science, Innovation and Universities postdoctoral contract(IJC-2019-038968). ZMR was supported by a postdoctoral contract co-funded by the Generalitat Valenciana and the European Social Fund(APOSTD/2019/016)

Scavenger assemblages are structured by complex competition and facilitation processes among vultures

Understanding the factors that allow multiple species to coexist and share resources is an outstanding question in community ecology. Animals that share resources tend to use different strategies to decrease potential competition, through morphological adaptations, establishment of hierarchies, behavioral adaptations or spatial or temporal segregation. The main objective of this study was to infer interspecific processes of competition and facilitation through the study of species co-occurrence patterns in a vertebrate scavenger guild in de Brazilian cerrado. We analyzed patterns of spatial and temporal co-occurrence between species pairs, both qualitatively and quantitatively, and determined the activity patterns of the different scavenger species. For this purpose, we placed and monitored 11 large (i.e. goat) and 45 small (i.e. chicken) carcasses by camera-trapping, obtaining a total of 27 448 images. Our results show complex competitive and facilitative relationships among scavenging species in the Brazilian cerrado that are influenced by carcass size and change depending on the spatial and temporal scale at which they are analyzed. The scavenger assemblages that consumed large and small carcasses were different, evidencing resource partitioning between obligate and facultative scavengers. Furthermore, as an alternative to reduce competition levels, most species showed differences in their scavenging patterns, in addition to a strong temporal segregation during carcass consumption. Regarding New World vultures, our results suggest a strong interference competition between species with clear differences in their ecological traits (e.g. size, social behavior). However, we also found evidence of facilitation processes between vulture species in the location and access to the interior of the carcasses. Our findings highlight the role of obligate scavengers both in competition and facilitation processes in this vertebrate scavenger community. Future research should focus on investigating which species play the most important role in the structure and dynamics of this community, also considering intraspecific and behavioral patterns.LNA, ZMR and ESG were supported by the Generalitat Valenciana and the European Social Fund (ACIF/2019/056, APOSTD/2019/016, SEJI/2018/024, respectively), and JASZ by funds from the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund (RTI2018-099609-B-C21). ESG received the grant RYC2019-027216-I funded by MCIN/AEI/10.13039/501100011033 and by ESF Investing in your future. ZMR was also supported by a postdoctoral contract funded by the Junta de Andalucía (POSTDOC_21_00353)

Avoidance of carnivore carcasses by vertebrate scavengers enables colonization by a diverse community of carrion insects

Enemérito Muñiz and Fernando Escribano helped during fieldwork. Dirección General del Medio Natural (Consejería de Agua, Agricultura y Medio Ambiente. Comunidad Autónoma de la Región de Murcia) and Sierra Espuña Regional Park provided help with logistics and permissions. Stefano Vanin and an anonymous reviewer provided useful comments and suggestions on the present manuscript.Carrion resources sustain a complex and diverse community of both vertebrate and invertebrate scavengers, either obligate or facultative. However, although carrion ecology has received increasing scientific attention in recent years, our understanding of carrion partitioning in natural conditions is severely limited as most studies are restricted either to the vertebrate or the insect scavenger communities. Moreover, carnivore carcasses have been traditionally neglected as study model. Here, we provide the first data on the partitioning between vertebrate and invertebrate scavengers of medium-sized carnivore carcasses, red fox (Vulpes vulpes (Linnaeus)), in two mountainous Mediterranean areas of south-eastern Spain. Carcasses were visited by several mammalian and avian scavengers, but only one carcass was partially consumed by golden eagle Aquila chrysaetos (Linnaeus). These results provide additional support to the carnivore carrion-avoidance hypothesis, which suggests that mammalian carnivores avoid the consumption of carnivore carcasses to prevent disease transmission risk. In turn, the absence of vertebrate scavengers at carnivore carcasses enabled a diverse and well-structured successional community of insects to colonise the carcasses. The observed richness and abundance of the most frequent families was more influenced by the decomposition time than by the study area. Overall, our study encourages further research on carrion resource partitioning in natural conditions.D.M.-V. was supported by an EC funded Marie Curie Intra-European Fellowship (FP7-PEOPLE-2013-IEF-624575) and a research contract from the University of Alcalá (Ayudas Postdoctorales UAH), Z.M.-R. by a pre-doctoral grant (FPU12/00823), and M.M. by a research contract Ramón y Cajal from the MINECO (RYC-2015-19231). This study was partly funded by the Spanish Ministry of Economy, Industry and Competitiveness and EU ERDF funds through the projects CGL2015-66966-C2-1-2-R and CGL2017-89905-R

The underestimated role of carrion in vertebrates' diet studies

Aim: Despite the increasing scientific evidence on the importance of carrion in the ecology and evolution of many vertebrates, scavenging is still barely considered in diet studies. Here, we draw attention to how scientific literature has underestimated the role of vertebrates as scavengers, identifying the ecological traits that characterize those species whose role as scavengers could have gone especially unnoticed. Location: Global. Time Period: 1938–2022. Major Taxa Studied: Terrestrial vertebrate scavengers. Methods: We analysed and compared (a) the largest database available on scavenging patterns by carrion-consuming vertebrates, (b) 908 diet studies about 156 scavenger species and (c) one of the most complete databases on bird and mammal diets (Elton Traits database). For each of these 156 species, we calculated their scavenging degree (i.e. proportion of carcases where the species is detected consuming carrion) as a proxy for carrion consumption, and related their ecological traits with the probability of being identified as scavengers in diet studies and in the Elton Traits database. Results: More than half of the species identified as scavengers at monitored carcasses were not assigned carrion as food source in their diet studies nor in the Elton Traits database. Using a subset of study sites, we found a direct relationship between a species' scavenging degree and its rate of carrion biomass removal. In addition, scavenger species, which were classified as non-predators and mammals had a lower probability of being identified as scavengers in diet studies and in the Elton Traits database, respectively. Main Conclusions: Our results clearly indicate an underestimation of the role of scavenging in vertebrate food webs. Given that detritus recycling is fundamental to ecosystem functioning, we encourage further recognition and investigation of the role of carrion as a food resource for vertebrates, especially for non-predator species and mammals with higher scavenging degree.JM was supported by a Basque Government predoctoral grant (PRE_2018_2_0112), ZMR, LNA and EA by contracts co-funded by the Generalitat Valenciana and the European Social Fund (ESF) (APOSTD/2019/016, ACIF/2019/056 and APOSTD/2021/028 respectively). MM, JMPG and ESG were funded by MCIN/AEI/10.13039/501100011033, by ‘European Union NextGenerationEU/PRTR’, ERDF ‘A way of making Europe’ and by ESF ‘Investing in your future’ (grant numbers RYC-2015-19231, IJC-2019-038968, TED2021-130890B-C21, PID2021-128952NB-I00 and RYC-2019-027216-I). ESG was also partially funded by the HORIZONMSCA-2021-SE-0 action number: 101086387, ‘REMARKABLE’ project. ZMR and DRG were also funded by the Junta de Andalucía (POSTDOC_21_00353 and PREDOC_00262). RPR was co-funded by the ESF and Plan Propio I+D+i UCLM

Unravelling the vertebrate scavenger assemblage in the Gobi Desert, Mongolia

Despite the essential role that vertebrate scavengers play in ecosystems, most studies have been conducted in Europe and North America, and there is a lack of information on vertebrate scavengers in vast regions of the world. Our aim was to describe the functioning and composition of the unknown vertebrate scavenger assemblage in the Gobi Desert, Mongolia, and determine how carcass size and habitat type affect species composition and carrion use. We monitored carcasses with camera traps and we also conducted observation points to survey the raptor community and identify the proportion of raptor species making use of the carcasses. We recorded eight vertebrate scavenger species (five birds and three mammals) by camera trap and seven raptors at observation points. Over half of the raptor species recorded at the observation points were also found feeding on carrion. The two most threatened species were only recorded in the mountain habitat. Furthermore, scavenger abundance and consumption rates were higher at large carcasses. This study highlights the importance of scavenging by raptors and other vertebrate scavengers for carrion elimination in ecosystems with extreme climatic conditions.AOT, JMPG, ZMR, LNA and ESG were supported by Generalitat Valenciana (SEJI/2018/024), ZMR and LNA also by contracts co-funded by the Generalitat Valenciana and the European Social Fund (APOSTD/2019/016 and ACIF/2019/056, respectively), and JASZ by funds from the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund (RTI 2018-099609-B-C21)

The value of transhumance for biodiversity conservation: Vulture foraging in relation to livestock movements

Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.In recent decades, intensive techniques of livestock raising have flourished, which has largely replaced traditional farming practices such as transhumance. These changes may have affected scavengers’ behaviour and ecology, as extensive livestock is a key source of carrion. This study evaluates the spatial responses of avian scavengers to the seasonal movements of transhumant herds in south-eastern Spain. We surveyed the abundance of avian scavengers and ungulates, and analysed the factors affecting the space use by 30 GPS-tracked griffon vultures (Gyps fulvus). Griffons’ foraging activity increased in the pasturelands occupied by transhumant herds, which implied greater vulture abundance at the landscape level during the livestock season. In contrast, facultative scavengers were more abundant without transhumant livestock herds, and the abundance of wild ungulates did not change in relation to livestock presence. We conclude that fostering transhumance and other traditional farming systems, to the detriment of farming intensification, could favour vulture conservation.CRUE-CSICSpringer Natur

Human-carnivore relations: conflicts, tolerance and coexistence in the American West

Carnivore and humans live in proximity due to carnivore recovery efforts and ongoing human encroachment into carnivore habitats globally. The American West is a region that uniquely exemplifies these human-carnivore dynamics, however, it is unclear how the research community here integrates social and ecological factors to examine human-carnivore relations. Therefore, strategies promoting human-carnivore coexistence are urgently needed. We conducted a systematic review on human-carnivore relations in the American West covering studies between 2000 and 2018. We first characterized human-carnivore relations across states of the American West. Second, we analyzed similarities and dissimilarities across states in terms of coexistence, tolerance, number of ecosystem services and conflicts mentioned in literature. Third, we used Bayesian modeling to quantify the effect of social and ecological factors influencing the scientific interest on coexistence, tolerance, ecosystem services and conflicts. Results revealed some underlying biases in humancarnivore relations research. Colorado and Montana were the states where the highest proportion of studies were conducted with bears and wolves the most studied species. Non-lethal management was the most common strategy to mitigate conflicts. Overall, conflicts with carnivores were much more frequently mentioned than benefits. We found similarities among Arizona, California, Utah, and New Mexico according to how coexistence, tolerance, services and conflicts are addressed in literature. We identified percentage of federal/private land, carnivore family, social actors, and management actions, as factors explaining how coexistence, tolerance, conflicts and services are addressed in literature. We provide a roadmap to foster tolerance towards carnivores and successful coexistence strategies in the American West based on four main domains, (1)the dual role of carnivores as providers of both beneficial and detrimental contributions to people, (2)social-ecological factors underpinning the provision of beneficial and detrimental contributions, (3)the inclusion of diverse actors, and (4) cross-state collaborative management

Rethinking megafauna

Concern for megafauna is increasing among scientists and non-scientists. Many studies have emphasized that megafauna play prominent ecological roles and provide important ecosystem services to humanity. But, what precisely are “megafauna”? Here we critically assess the concept of megafauna and propose a goal-oriented framework for megafaunal research. First, we review definitions of megafauna and analyze associated terminology in the scientific literature. Second, we conduct a survey among ecologists and paleontologists to assess the species traits used to identify and define megafauna. Our review indicates that definitions are highly dependent on the study ecosystem and research question, and primarily rely on ad hoc size-related criteria. Our survey suggests that body size is crucial, but not necessarily sufficient, for addressing the different applications of the term megafauna. Thus, after discussing the pros and cons of existing definitions, we propose an additional approach by defining two function-oriented megafaunal concepts: “keystone megafauna” and “functional megafauna”, with its variant “apex megafauna”. Assessing megafauna from a functional perspective could challenge the perception that there may not be a unifying definition of megafauna that can be applied to all eco-evolutionary narratives. In addition, using functional definitions of megafauna could be especially conducive to cross-disciplinary understanding and cooperation, improvement of conservation policy and practice, and strengthening of public perception. As megafaunal research advances, we encourage scientists to unambiguously define how they use the term “megafauna” and to present the logic underpinning their definition

Vertebrate populations' trends across the Iberian Peninsula

Resumen del trabajo presentado a: 2nd Meeting of the Iberian Ecological Society (SIBECOL); XXI conference of the Iberian Association of Limnology (AIL) and 21st National Congress of Ecology of the Portuguese Ecological Society (SPECO), celebrados en Aveiro (Portugal) del 3 al 8 de julio de 2022.Understanding and identifying the impacts of multiple stressors on natural populations has become a key objective for post-2020 biodiversity conservation. Of particular concern are the impacts of stressors at the local scale, which are not necessarily reflected in current global conservation assessments. As a hotspot of biodiversity, the Iberian Peninsula is an area of special interest for conservation, but it is currently facing myriad environmental problems. Yet, a synthesis of the impacts of multiple stressors on the Iberian faunal populations is glaringly missing. To contribute to this challenge, we join our efforts in an Early Career Researchers project funded by SIBECOL, which aims to synthesise current knowledge on population trends of Iberian marine, terrestrial and freshwater vertebrates, and, eventually, to identify the most common stressors for Iberian fauna populations, and their differences between major taxonomic groups and ecosystems. Here, we will present the results of the first phase of this project, whose objective was to describe the trends of Iberian vertebrate populations and identify knowledge gaps related to taxonomic groups and ecosystems. To that aim, we conducted an extensive literature review, with more than 5,000 scientific manuscripts and grey literature screened. From this initial review, and after applying data quality controls, we obtained > 1,000 population time series of Iberian vertebrates across marine, terrestrial, and freshwater ecosystems. Once we compiled this database, we analysed the population trends using a two-step modelling process: (i) first, we applied state-space models to derive the population trend of each population time series; and (ii) second, we used multilevel Bayesian models to determine the factors influencing these population trends. Overall, we found that Iberian vertebrate populations display a disparity in trends, with both declines and increases, with fishes (both marine and freshwater) being the taxa showing clear signs of decline. Additionally, we identified important gaps in monitoring data across the Iberian Peninsula, with amphibians and reptiles severely underrepresented in our dataset, despite being among the most threatened taxonomic groups. These gaps may limit our understanding of the impacts of stressors at local scales and eventually bias current conservation assessments. Overall, our approach will bridge the significant gap in our knowledge between the global and local scale conservation status of wild Iberian populations and help focus future conservation policies.Peer reviewe

Network Structure of Vertebrate Scavenger Assemblages at the Global Scale: Drivers and Ecosystem Functioning Implications

The organization of ecological assemblages has important implications for ecosystem functioning, but little is known about how scavenger communities organize at the global scale. Here, we test four hypotheses on the factors affecting the network structure of terrestrial vertebrate scavenger assemblages and its implications on ecosystem functioning. We expect scavenger assemblages to be more nested (i.e. structured): 1) in species‐rich and productive regions, as nestedness has been linked to high competition for carrion resources, and 2) regions with low human impact, because the most efficient carrion consumers that promote nestedness are large vertebrate scavengers, which are especially sensitive to human persecution. 3) We also expect climatic conditions to affect assemblage structure, because some scavenger assemblages have been shown to be more nested in colder months. Finally, 4) we expect more organized assemblages to be more efficient in the consumption of the resource. We first analyzed the relationship between the nestedness of the scavenger assemblages and climatic variables (i.e. temperature, precipitation, temperature variability and precipitation variability), ecosystem productivity and biomass (i.e. NDVI) and degree of human impact (i.e. human footprint) using 53 study sites in 22 countries across five continents. Then, we related structure (i.e. nestedness) with its function (i.e. carrion consumption rate). We found a more nested structure for scavenger assemblages in regions with higher NDVI values and lower human footprint. Moreover, more organized assemblages were more efficient in the consumption of carrion. However, our results did not support the prediction that the structure of the scavenger assemblages is directly related to climate. Our findings suggest that the nested structure of vertebrate scavenger assemblages affects its functionality and is driven by anthropogenic disturbance and ecosystem productivity worldwide. Disarray of scavenger assemblage structure by anthropogenic disturbance may lead to decreases in functionality of the terrestrial ecosystems via loss of key species and trophic facilitation processes