New publicatoion: when and where Black Kites die !

Sergio, F., Tavecchia, G., Tanferna, A., Blas, J., Blanco, G., and Hiraldo, F. 2019: When and where mortality occurs throughout the annual cycle changes with age in a migratory birds: indiviudal vs population implications. Scientific Reports, 9, 17352.

Photo: F. Sergio

Abstract: The annual cycle of most animals is structured into discrete stages, such as breeding, migration and dispersal. While there is growing appreciation of the importance of different stages of an organism’s annual cycle for its fitness and population dynamics, almost nothing is known about if and how such seasonal effects can change through a species lifespan. Here, we take advantage of the opportunity offered by a long-term satellite/GPS-tracking study and a reliable method of remote death-detection to show that certain stages of both the annual and life cycle of a migratory long-lived raptor, the Black kite Milvus migrans, may represent sensitive bottlenecks for survival. In particular, migratory journeys caused bursts of concentrated-mortality throughout life, but the relative importance of stage-specific survival changed with age. On the other hand, the balance between short-stages of high mortality and long-stages of low mortality made population-growth similarly dependent on all portions of the annual cycle. Our results illustrate how the population dynamics of migratory organisms can be inextricably linked to ecological pressures balanced over multiple stages of the annual cycle and thus multiple areas of the globe, suggesting the frequent need for challenging conservation strategies targeting all portions of a species year-round range.

New Publication on individual-based model and extinction!

Graciá, E., Rodríguez-Caro, R., Sanz-Aguilar, A., [...] Giménez, A., 2020. Assessment of the key evolutionary traits that prevent extinctions in human-altered habitats using a spatially explicit individual-based model. Ecological Modelling Vol 415. https://doi.org/10.1016/j.ecolmodel.2019.108823

Abstract: Identifying key evolutionary strategies that support population persistence remains a challenging task for biodiversity conservation. Here we assess if animal adaptations to cope with low densities (i.e. that facilitate mate-findings or promote spatial aggregation of individuals) can allow species to persist in human-altered habitats.
A spatially explicit and individual-based model was developed to assess if, and under what circumstances, such adaptations maintain population viability. The model was parameterised with data from the movement and demography of the spur-thighed tortoise (Testudo graeca) and simulated scenarios with differences in adult survivorships, initial population sizes and habitat alterations. Habitat alterations reduced population viability, and extinction rates were dependent on population characteristics and mate-finding distance. In contrast, philopatry around the birthplace did not prevent extinctions. Our results highlight the importance of considering specific spatial traits of species when assessing their vulnerability to human habitat alterations.

GEDA on Air and at the Science Week 2019 !

A. Sanz-Aguilar a Balear Fa Ciencia (min 26) explained the Speed Dating with Researchers and introduced the Storm Petrel, the smallest seabird. The GEDA will be at the Science Speed Dating this Monday (more information here).

New Publication on rewilding and scavangers!

Arrondo, E., Morales-Reyes, Z., Moleón, M., Cortés-Avizanda, A., Donázar, J.A. and Sánchez-Zapata, J.A. 2019 Rewilding traditional grazing areas affects scavenger assemblages and carcass consumption patterns Basic and App Ecol, https://doi.org/10.1016/j.baae.2019.10.006

Abstract: The abandonment of traditional livestock farming systems in Mediterranean countries is triggering a large-scale habitat transformation, which, in general, consists of the replacement of open grazing areas by woodlands through non-managed regeneration. As a consequence, wild ungulates are occupying rapidly the empty niche left by domestic ungulates. Both types of ungulates represent the main trophic resource for large vertebrate scavengers. However, a comparison of how vertebrate scavengers consume ungulate carcasses in different habitats with different ungulate species composition is lacking. This knowledge is essential to forecast the possible consequences of the current farmland abandonment on scavenger species. Here, we compared the scavenging patterns of 24 wild and 24 domestic ungulate carcasses in a mountainous region of southern Spain monitored through camera trapping. Our results show that carcasses of domestic ungulates, which concentrate in large numbers in open pasturelands, were detected and consumed earlier than those of wild ungulate carcasses, which frequently occur in much lower densities at more heterogenous habitats such as shrublands and forest. Richness and abundance of scavengers were also higher at domestic ungulate carcasses in open habitats. Vultures, mainly griffons (Gyps fulvus), consumed most of the carcasses, although mammalian facultative scavengers, mainly wild boar (Sus scrofa) and red fox (Vulpes vulpes), also contributed importantly to the consumption of wild ungulate carcasses in areas with higher vegetation cover. Our findings evidence that the abandonment of traditional grazing may entail consequences for the scavenger community, which should be considered by ecologists and wildlife managers.

See a press note (in Spanish) here

FPU theme: Resilience of seabird populations

We are offering supervision for a PhD student within the National program "Formacion de Profesorado Universitario" . The research will be framed into the National Project  CGL2017-85210-P on the Resilience of Seabird Population to Natural and Anthropogenic perturbations. More in formation on how to apply for an FPU grant here and about the project here.