jueves, 28 de mayo de 2015

New publication on Raptors on Islands

Sanz-Aguilar A, de Pablo F, Donázar JA. Age-dependent survival of island vs. mainland populations of two avianscavengers: delving into migration costs. Oecologia, in press (doi:10.1007/s00442-015-3355-x) 

Abstract: Large terrestrial long-lived birds (including raptors) are typically sedentary on islands, even when they are migratory on the mainland. Density-dependent variation in the age at first breeding has been described as responsible for the long-term persistence of long-lived bird populations on islands. However, sedentary island populations may also benefit from higher survival rates derived from the absence of migration costs, especially for young individuals. Thus, sedentary island populations can mimic a natural experiment to study migration costs. 
Photo: Felix de Pablo

We estimated the age-dependent survival of two sedentary raptors on Menorca Island (Egyptian vultures Neophron percnopterus and red kites Milvus milvus) and compared these estimates with those reported for other migratory and sedentary populations. In Menorca, Egyptian vultures, but not red kites, showed low levels of human-related mortality resulting in extremely high survival probabilities, probably due to different diet choices and behavioral patterns. Juvenile Egyptian vultures and red kites in the studied population had lower survival probabilities than adults. This difference, however, was smaller than those reported for mainland migrant populations, which showed a lower juvenile survival rate. In fact, between-population comparisons suggested that survival of the young in migrant populations may be triggered by mortality factors in wintering areas. In contrast, adult survival may respond to mortality factors in breeding areas. Our results suggest that raptor species that become sedentary on islands may benefit from higher pre-breeder survival prospects in comparison with their mainland migrant counterparts. This fact, in combination with an earlier age at first reproduction, may facilitate their persistence.

martes, 26 de mayo de 2015

Highlight in Nature Climate Change Journal

Our paper on how sex in reptiles is temperature-dependant (TSD) and how climate change may affect species persistence has been highlighted in Nature Climate Change.

Scopoli's Shearwater campaign

Photo: P. Arcos

The annual campaign on the ecology of  the Scopoli's Shearwater Calonectris diomedea has started with the first breeding pairs at the colony. We will assess laying date, breeding success and collect individual data on presence-absence of marked birds. The hard work will end in September, when the newborns will leave for their first trans-equatorial migration. Check the publications by the GEP to learn more on this incredible bird here .

viernes, 22 de mayo de 2015

Still growing...PhD at the GEP

Enrique Real Garcías joined the GEP for a Ph.D. supported by the MINECO. He will deal with the difficult task of estimating fishery induced mortality of seabirds. His challenge will be to couple bycatch data, seabird surveys and capture-recapture data to estimate the mortality caused by fishery. The project will be developed in collaboration with the Balearic Center of Oceanography (IEO). Welcome Enrique.

lunes, 18 de mayo de 2015

Erasmus+ at the GEP

Serena Manserra is joining the GEP for four months as part of her training in the Erasmus+ program of the University of Pavia (Italy). Serena will investigate the factors influencing the breeding success of Scopoli's shearwaters. Welcome Serena !

viernes, 8 de mayo de 2015

New publication on Egyptian vulture!

Sanz-Aguilar A, Sánchez-Zapata JA, Carrete M, Benítez JR, Ávila E, Arenas R & Donázar JA. 2015. Action on multiple fronts, illegal poisoning and wind farm planning, is required to reverse the decline of the Egyptian vulture in Southern Spain. Biological Conservation  187:10-18.

Abstract: Large body-sized avian scavengers, including the Egyptian vulture (Neophron percnopterus), are globally threatened due to human-related mortality so guidelines quantifying the efficacy of different management approaches are urgently needed. We used 14 years of territory and individual-based data on a small and geographically isolated Spanish population to estimate survival, recruitment and breeding success. We then forecasted their population viability under current vital rates and under management scenarios that mitigated the main sources of non-natural mortality at breeding grounds (fatalities from wind farms and illegal poisoning).
Photo: A. Atienza
Mean breeding success was 0.68 (SD=0.17) under current conditions. Annual probabilities of survival were 0.72 (SE=0.06) for fledglings and 2 yr old non-breeders, 0.73 (SE=0.04) for non-breeders older than 2 yrs old and 0.93 (SE=0.04) for breeders. Probabilities of recruitment were 0 for birds aged 1 to 4, 0.10 (SE=0.06) for birds aged 5 and 0.19 (SE=0.09) for older birds. Population viability analyses estimated an annual decline of 3-4% of the breeding population under current conditions. Our results indicate that only by combining different management actions in the breeding area, especially by removing the most important causes of human-related mortality (poisoning and collisions on wind farms), will the population grow and persist in the long term. Reinforcement with captive breeding may also have positive effects but only in combination with the reduction in causes of non-natural mortality. These results, although obtained for a focal species, may be applicable to other endangered populations of long-lived avian scavengers inhabiting southern Europe.

lunes, 4 de mayo de 2015

New publication on seaturtles and global change!

Santidrian Tomillo, P., Genovart, M., Paladino, F. V., Spotila, J. R. and Oro, D. Climate change overruns resilience conferred by temperature-dependent sex determination in sea turtlesand threatens their survival. Global Change Biology doi: 10.1111/gcb.12918

Abstract: Temperature-dependent sex determination (TSD) is the predominant form of environmental sex determination (ESD) in reptiles, but the adaptive significance of TSD in this group remains unclear. Additionally, the viability of species with TSD may be compromised as climate gets warmer. We simulated population responses in a turtle with TSD to increasing nest temperatures and compared the results to those of a virtual population with genotypic sex determination (GSD) and fixed sex ratios.
Photo from the web
Then, we assessed the effectiveness of TSD as a mechanism to maintain populations under climate change scenarios. TSD populations were more resilient to increased nest temperatures and  mitigated the negative effects of high temperatures by increasing production of female offspring and therefore, future fecundity. That buffered the negative effect of temperature on the population growth. TSD provides an evolutionary advantage to sea turtles. However, this mechanism was only effective over a range of temperatures and will become inefficient as temperatures rise to levels projected by current climate change models. Projected global warming threatens survival of sea turtles, and the IPCC high gas concentration scenario may result in extirpation of the studied population in 50 years.

viernes, 1 de mayo de 2015

YLG 2015 campaign ended today

The Yellow Legged gull campaign ended today with twenty-seven gulls marked, two surveys and eighty clutches measured along the path to the Llebeig lighthouse. Thank to everyone who helped. Eleanor Falcons have just arrived, time for us to go. 
See you next year!