Behavioral interactions are modulated by facilitation along a heterotrophic succession.

Competition and facilitation drive ecological succession but are often hard to quantify. In this sense, behavioral data may be a key tool to analyze interaction networks, providing insights into temporal trends in facilitation and competition processes within animal heterotrophic succession. Here, we perform the first in-depth analysis of the factors driving temporal dynamics of carcass consumption by analyzing behavioral patterns (i.e., interactions) and community dynamics metrics (i.e., species richness, abundance, turnover, and diversity) in a Neotropical scavenger guild. For this purpose, we monitored goat carcasses using automatic cameras. From 573 reviewed videos, we registered 1784 intraspecific and 624 interspecific interactions, using intraspecific and interspecific aggressions (n = 2048) as a behavioral proxy of competition intensity. Our results show that resource availability shapes behavioral interactions between vultures, with a specific effect of the different species on behavioral and competition dynamics, showing the existence of a hierarchy between species. Furthermore, behavioral processes linked to carcass opening tended to be facilitative, related to moments of higher tolerance (i.e., lower aggressiveness), thus reducing competition intensity and also affecting community structure and dynamics. This novel framework demonstrates complex ephemeral successional processes characterized by a fluctuation in facilitation and competition intensity during the consumption of an unpredictable resource linked to key ecosystem processes.

Vulture culture: dietary specialization of an obligate scavenger.

Individual dietary variation has important ecological and evolutionary consequences. However, it has been overlooked in many taxa that are thought to have homogeneous diets. This is the case of vultures, considered merely as 'carrion eaters'. Given their high degree of sociality, vultures are an excellent model to investigate how inter-individual transmissible behaviours drive individual dietary variation. Here, we combine GPS-tracking and accelerometers with an exhaustive fieldwork campaign to identify the individual diet of 55 griffon vultures (Gyps fulvus) from two Spanish populations that partially overlap in their foraging areas. We found that individuals from the more humanized population consumed more anthropic resources (e.g. stabled livestock or rubbish), resulting in more homogeneous diets. By contrast, individuals from the wilder population consumed more wild ungulates, increasing their dietary variability. Between sexes, we found that males consumed anthropic resources more than females did. Interestingly, in the shared foraging area, vultures retained the dietary preference of their original population, highlighting a strong cultural component. Overall, these results expand the role of cultural traits in shaping key behaviours and call for the need of including cultural traits in Optimal Foraging models, especially in those species that strongly rely on social information while foraging.

Large-scale movement patterns in a social vulture are influenced by seasonality, sex, and breeding region.

Quantifying space use and segregation, as well as the extrinsic and intrinsic factors affecting them, is crucial to increase our knowledge of species-specific movement ecology and to design effective management and conservation measures. This is particularly relevant in the case of species that are highly mobile and dependent on sparse and unpredictable trophic resources, such as vultures. Here, we used the GPS-tagged data of 127 adult Griffon Vultures Gyps fulvus captured at five different breeding regions in Spain to describe the movement patterns (home-range size and fidelity, and monthly cumulative distance). We also examined how individual sex, season, and breeding region determined the cumulative distance traveled and the size and overlap between consecutive monthly home-ranges. Overall, Griffon Vultures exhibited very large annual home-range sizes of 5027 ± 2123 km2, mean monthly cumulative distances of 1776 ± 1497 km, and showed a monthly home-range fidelity of 67.8 ± 25.5%. However, individuals from northern breeding regions showed smaller home-ranges and traveled shorter monthly distances than those from southern ones. In all cases, home-ranges were larger in spring and summer than in winter and autumn, which could be related to difference in flying conditions and food requirements associated with reproduction. Moreover, females showed larger home-ranges and less monthly fidelity than males, indicating that the latter tended to use the similar areas throughout the year. Overall, our results indicate that both extrinsic and intrinsic factors modulate the home-range of the Griffon Vulture and that spatial segregation depends on sex and season at the individual level, without relevant differences between breeding regions in individual site fidelity. These results have important implications for conservation, such as identifying key threat factors necessary to improve management actions and policy decisions.

Cuantificar el uso y la segregación del espacio, así como los factores extrínsecos e intrínsecos que los afectan, es crucial para aumentar nuestro conocimiento de la ecología de movimientos de cada especie y diseñar medidas eficaces de gestión y conservación. Esto es especialmente relevante en el caso de especies con gran movilidad y dependientes de recursos tróficos escasos e impredecibles, como son los buitres. En este trabajo se utilizaron datos GPS de 127 buitres leonados Gyps fulvus adultos capturados en cinco regiones de cría diferentes en España para describir los patrones de movimiento (tamaño y fidelidad del área de campeo y distancia acumulada mensual). También examinamos cómo el sexo, la estación del año y la región de cría determinaban la distancia acumulada recorrida y el tamaño y solapamiento entre áreas de campeo mensuales consecutivas. En conjunto, los buitres leonados mostraron un área de campeo anual muy extensa de 5027 ± 2123 km2, una distancia acumulada mensual media de 1776 ± 1497 km y una fidelidad mensual al área de campeo del 67.8 ± 25.5%. Sin embargo, los individuos de las regiones de cría más septentrionales mostraron áreas de campeo más pequeñas y recorrieron distancias mensuales más cortas que los de las más meridionales. En todos los casos, las áreas de campeo fueron mayores en primavera y verano que en otoño e invierno, lo que podría estar relacionado con las diferencias en las condiciones de vuelo y las necesidades tróficas asociadas a la reproducción. Además, las hembras mostraron mayores áreas de campeo y menor fidelidad mensual que los machos, lo que indica que estos últimos tienden a utilizar zonas similares durante todo el año. En conjunto, nuestros resultados indican que tanto los factores extrínsecos como los intrínsecos modulan el área de campeo del buitre leonado y que la segregación espacial depende del sexo y de la estación a nivel individual, sin que existan diferencias relevantes entre las regiones de cría en cuanto a la fidelidad individual al lugar. Estos resultados podrían tener importantes implicaciones para la conservación, como la identificación de los principales factores necesarios para mejorar las medidas de gestión y las decisiones políticas.

Scavenging in the realm of senses: smell and vision drive recruitment at carcasses in Neotropical ecosystems.

Social information, acquired through the observation of other individuals, is especially relevant among species belonging to the same guild. The unpredictable and ephemeral nature of carrion implies that social mechanisms may be selected among scavenger species to facilitate carcass location and consumption. Here, we apply a survival-modelling strategy to data obtained through the placement and monitoring of carcasses in the field to analyse possible information transmission cascades within a Neotropical scavenger community. Our study highlights how the use of different senses (smell and sight) within this guild facilitates carcass location through the transmission of social information between species with different carrion foraging efficiencies. Vultures with a highly developed sense of smell play a key role in this process, as they are the first to arrive at the carcasses and their presence seems to serve as a visual cue for other species to locate the resource. Our study supports the local enhancement hypothesis within scavengers, whereby individuals locate carcasses by following foraging heterospecifics, also suggesting the importance of the sense of smell in the maintenance of the community structure.

Scavenger guild and consumption patterns of an invasive alien fish species in a Mediterranean wetland.

Invasive Alien Species (IAS) alter ecosystems, disrupting ecological processes and driving the loss of ecosystem services. The common carp Cyprinus carpio is a hazardous and widespread IAS, becoming the most abundant species in many aquatic ecosystems. This species transforms ecosystems by accumulating biomass to the detriment of other species, thus altering food webs. However, some terrestrial species, such as vertebrate scavengers, may benefit from dead carps, by incorporating part of the carp biomass into the terrestrial environment. This study describes the terrestrial vertebrate scavenger assemblage that benefits from carp carcasses in a Mediterranean wetland. We also evaluate the seasonal differences in the scavenger assemblage composition and carrion consumption patterns. Eighty carp carcasses (20 per season) were placed in El Hondo Natural Park, a seminatural mesohaline wetland in south-eastern Spain, and we monitored their consumption using camera traps. We recorded 14 scavenger species (10 birds and four mammals) consuming carp carcasses, including globally threatened species. Vertebrates consumed 73% of the carrion biomass and appeared consuming at 82% of the carcasses. Of these carcasses consumed, 75% were completely consumed and the mean consumption time of carcasses completely consumed by vertebrates was 44.4 h (SD = 42.1 h). We recorded differences in species richness, abundance, and assemblage composition among seasons, but we did not find seasonal differences in consumption patterns throughout the year. Our study recorded a rich and efficient terrestrial vertebrate scavenger assemblage benefitting from carp carcasses. We detected a seasonal replacement on the scavenger species, but a maintenance of the ecological function of carrion removal, as the most efficient carrion consumers were present throughout the year. The results highlight the importance of vertebrate scavengers in wetlands, removing possible infectious focus, and moving nutrients between aquatic and terrestrial environments.

Dust and bullets: Stable isotopes and GPS tracking disentangle lead sources for a large avian scavenger.

Lead intoxication is an important threat to human health and a large number of wildlife species. Animals are exposed to several sources of lead highlighting hunting ammunition and lead that is bioavailable in topsoil. Disentangling the role of each in lead exposure is an important conservation issue, particularly for species potentially affected by lead poisoning, such as vultures. The identification of lead sources in vultures and other species has been classically addressed by means of stable-isotope comparisons, but the extremely varied isotope signatures found in ammunition hinders this identification when it overlaps with topsoil signatures. In addition, assumptions related to the exposure of individual vultures to lead sources have been made without knowledge of the actual feeding grounds exploited by the birds. Here, we combine lead concentration analysis in blood, novel stable isotope approaches to assign the origin of the lead and GPS tracking data to investigate the main foraging grounds of two Iberian griffon vulture populations (N = 58) whose foraging ranges differ in terms of topsoil lead concentration and intensity of big game hunting activity. We found that the lead signature in vultures was closer to topsoil than to ammunition, but this similarity decreased significantly in the area with higher big game hunting activity. In addition, attending to the individual home ranges of the tracked birds, models accounting for the intensity of hunting activity better explained the higher blood lead concentration in vultures than topsoil exposure. In spite of that, our finding also show that lead exposure from topsoil is more important than previously thought.

Scientific priorities and shepherds' perceptions of ungulate's contributions to people in rewilding landscapes.

Nature's contributions to people (NCP) are all the contributions of living nature, both beneficial and detrimental, to the societies' life's quality. Ungulates play this dual role of providers of beneficial and detrimental NCP, as they are responsible of the supply of benefits (e.g. extractive experiences, habitat maintenance) and detriments (e.g. crops damage, traffic collisions). Our aim was to analyze the NCP provided by wild ungulates through examining the scientific priorities and the shepherds' perceptions in peninsular Spain. We reviewed scientific articles of NCP provided by ungulates in Spain and conducted questionnaires regarding NCP to shepherds in farming systems where domestic and wild ungulates cohabit. Then, we compared whether the scientific priorities match with those perceived by shepherds. Both stakeholders highlight more detrimental than beneficial NCP, although there are some mismatches between scientific priorities and shepherds' perceptions. Regarding detrimental NCP, soil alteration, silvicultural damage, human safety or traffic collision were included in scientific literature but not mentioned by shepherds. Contrarywise, shepherds mainly considered grazing competence and damage to animals (i.e. game species and livestock) as important detrimental NCP. Concerning beneficial NCP, whilst hunting was prominent in the publications, shepherds did not conceived it as an important beneficial contribution and considered the regulation of organisms (i.e. scavenging alternative prey) important benefits. These results can have twofold implications. The emphasis on detrimental NCP (studied and perceived) can reinforce the idea that ungulates can threaten humans rather than contribute to societies' wellbeing. The fact that research does not address the interests of shepherds can affect the social tolerance towards ungulates as the damages experienced or perceived by shepherds are not studied. Our results show the relevance of considering local knowledge held by shepherds and their perceptions, something highlighted by the NCP approach.

Spatiotemporal variations of organochlorine pesticides in an apex predator: Influence of government regulations and farming practices.

BACKGROUND: Intensification of agricultural practices has caused several negative effects to the environment. The use of fertilizers and pesticides may alter geochemical cycles or cause direct wildlife intoxication. Detrimental effects of organochlorine pesticides (OCPs) have forced the authorities to ban or restrict its use. This study evaluates the variation in levels of OCPs in a sentinel species in relation to changes in government regulations and the spatial configuration of agricultural practices around the nests. METHODS: Between 2003 and 2007, we analysed OCP levels in 256 blood samples of Eurasian Eagle-owl (Bubo bubo) chicks nesting in area of intensive commercial agriculture with historical frequent use of pesticides, in South-eastern Spain. We studied year-to-year variations in OCP concentrations and their relation with land use configuration around raptor nests by Generalized Linear Mixed Models (GLMM). RESULTS: OCPs were detected in 100% samples surveyed in 2003 and 2004, while dropped to 27% in 2005, 6.8% in 2006 and 6.3% in 2007, coinciding with the ban of OCPs. The presence of the main OCPs was related to agricultural practices. In particular, endosulfan and lindane were related to irrigated crops and urban areas, while DDT-related compounds and dieldrin were associated with dry land farming. CONCLUSIONS: OCP concentrations in blood samples of Eurasian Eagle-owls may respond quickly to the implementations of new regulations about the use of agricultural products. This raptor was confirmed as a good sentinel species allowing rapid detection of changes in pesticides use.

Genetic Signatures of Demographic Changes in an Avian Top Predator during the Last Century: Bottlenecks and Expansions of the Eurasian Eagle Owl in the Iberian Peninsula.

The study of the demographic history of species can help to understand the negative impact of recent population declines in organisms of conservation concern. Here, we use neutral molecular markers to explore the genetic consequences of the recent population decline and posterior recovery of the Eurasian eagle owl (Bubo bubo) in the Iberian Peninsula. During the last century, the species was the object of extermination programs, suffering direct persecution by hunters until the 70's. Moreover, during the last decades the eagle owl was severely impacted by increased mortality due to electrocution and the decline of its main prey species, the European rabbit (Oryctolagus cuniculus). In recent times, the decrease of direct persecution and the implementation of some conservation schemes have allowed the species' demographic recovery. Yet, it remains unknown to which extent the past population decline and the later expansion have influenced the current species' pattern of genetic diversity. We used eight microsatellite markers to genotype 235 eagle owls from ten Spanish subpopulations and analyse the presence of genetic signatures attributable to the recent population fluctuations experienced by the species. We found moderate levels of differentiation among the studied subpopulations and Bayesian analyses revealed the existence of three genetic clusters that grouped subpopulations from central, south-western and south-eastern Spain. The observed genetic structure could have resulted from recent human-induced population fragmentation, a patchy distribution of prey populations and/or the philopatric behaviour and habitat selection of the species. We detected an old population bottleneck, which occurred approximately 10,000 years ago, and significant signatures of recent demographic expansions. However, we did not find genetic signatures for a recent bottleneck, which may indicate that population declines were not severe enough to leave detectable signals on the species genetic makeup or that such signals have been eroded by the rapid demographic recovery experienced by the species in recent years.

Testing the heterospecific attraction hypothesis with time-series data on species co-occurrence.

The distributional patterns of actively moving animals are influenced by the cues that the individuals use for choosing sites into which they settle. Individuals may gather information about habitat quality using two types of strategies, either directly assessing the relevant environmental factors, or using the presence of conspecifics or heterospecifics as an indirect measure of habitat quality. We examined patterns of heterospecific attraction with observational time-series data on a community of seven waterbird species breeding in artificial irrigation ponds. We fitted to the data a multivariate logistic regression model, which attributes the presence-absence of each species to a set of environmental and spatial covariates, to the presence of con- and heterospecifics in the previous year and to the presence of heterospecifics in the same year. All species showed a clear tendency to continue breeding in the same sites where they were observed in the previous year. Additionally, the presence of heterospecifics, both in the previous year and in the same year, generally increased the probability that the focal species was found breeding on a given pond. Our data thus give support for the heterospecific attraction hypothesis, though causal inference should be confirmed with manipulative experiments.

Experiencia en hemorroidectomías aplicado en la Clínica Fiori / Experience in haemmorrhoidectomy at the clinica Fiori

Objetivo: Evaluar la utilidad de la cirugía ambulatoria con anestesia local en pacientes con patología hemorroidal. Material y métodos: Se realizó un estudio prospectivo, transversal, entre abril de 1996 y marzo de 1999, en el servicio de cirugía de la Clínica Fiori. Se intervinieron 260 pacientes por patología hemorroidal, de ellos 229 pacientes fueron sometidos a hemorroidectomía con anestesia local, los que fueron incluidos en el estudio. La técnica quirúrgica utilizada fue la de Milligan y Morgan con un tiempo operatorio de 20 minutos; y control a los 3 días. resultados: El 69.4 por ciento de patología hemorroidal se observó entre los 31-60 años de edad. Sólo el 1.7 por ciento (4 pacientes) presentaron complicaciones post-operatorias, 2 pacientes con sangrado leve y 2 con hemorroides residuales, ninguno resultó ser de gravedad; y el 98.3 por ciento (225 pacientes) no presentaron ningún tipo de complicaciones. No hubo accidentes anestésicos. Conclusión: La hemorroidectomía con anestesia local es efectiva y segura.