domingo, 19 de noviembre de 2017

martes, 7 de noviembre de 2017

New Publication on Yellow-Legged Gull and PAFS

Real, E., Oro, D., Martinez-Abrain, A., Igual, J.-M., Bertolero, A., Bosch, M.and Tavecchia, G., 2017. Predictable anthropogenic food subsidies, density-dependence and socio-economic factors influence breeding investment in a generalist seabird  Journal of Avian Biology, 48: 001–009
doi: 10.1111/jav.01454
Abstact:  Recent European policies on the ban of fishing discards and the closure of open-air landfills are expected to reduce predictable and abundant food resources for generalist seabirds. In order to forecast the consequences of this reduction on seabird breeding investment it is important to understand whether diverse anthropogenic foraging resources act synergistically or not and whether their influence is mediated by density-dependent mechanisms.
To assess these effects at large spatio-temporal scale, we measured mean egg volume as a proxy of breeding investment in ca 5000 three-egg clutches of the yellow-legged gull Larus michahellis from 20 colonies of the Western Mediterranean, located both along European and African coasts. In European gull colonies, egg volume increased with the availability of fishing discards and landfills in the vicinity of the colony. However, the landfill effect was weaker than the effect of fishing discards, probably due to the lower quality of waste as food for gulls. In contrast, none of the anthropogenic food subsidies influenced egg volume in African colonies, likely due to socio-economic differences (i.e. a much lower availability and predictability of both discards and waste food. Finally, results showed that the positive association between fishing discards and open-air landfills on egg volume was mediated by negative density-dependent mechanisms probably related to an increase in competition for food.

miércoles, 25 de octubre de 2017

Master’s degree project in Animal Ecology at the GEP

Jaume Badia is joining the GEP for his Master’s degree project in Animal Ecology at the University of Lund, Sweden. Jaume work will focus on the conservation maeasures to protect the Egyptian Vulture at Fuerteventura (Canary Islands) under the direction of Ana Sanz-Aguilar and in collaboration with the Estacion Biologica e Doñana (CSIC).

miércoles, 27 de septiembre de 2017

New Publication on the multidimensional value of long-term studies !

Tavecchia, G., Oro, D., Sanz-Aguilar, A., and Béchet, A. 2017. The multidimensional value of long-term individual.based studies: more than lots of data. Avocetta 41: 19-21

With the present rate of biodiversity loss and the profound effects of global changes, population and conservation ecologists face new questions. Many of these are related to how fast individuals can adapt to the strength and pace of environmental variability and can only be answered using individual data collected over long-term (Long Terms Individual Based Studies). Beside this undoubted scientific value, a 20 – 30 years study is likely to have trained several generations of scientists, fostered collaborations between a large number of research institutes and promoted public awareness on scientific themes and wildlife conservation problems. With current public systems providing funds for 3 to 4 years, it is increasingly difficult to initiate and maintain a long-term individual based study. As a consequence, many field studies end before time, without reaching the number of years or the amount of data needed to meet current scientific challenges and to demonstrate their educational value.Here, we argue that the value of LTIBS is multidimensional and it grows steadily with time. How and when does a long-term field study become important? [..] continue reading here

This text is in honor of Dr. Alan Roy Johnson (1941-2014, Photo), Dr. Heinz Hafner (1940-2003) and other pioneers of LTIBS. By focusing the attention on the multidimensional value of LTIBS we aimed to pay a tribute to them and to those people who, thanks to their passion, personal sacrifices and tenacity are keeping these projects alive.

A. Johnson (photo. H. Hôte)

lunes, 25 de septiembre de 2017

Visiting GEP

Dr. L. Corlatti is visiting the GEP for few weeks. Luca will work with G. Tavecchia and A. Sanz-Aguilar on estimating mortality of deers at the Stelvio National Park using radio-tracking data. 

viernes, 22 de septiembre de 2017

Ph.D. Defense!

Noelia Hernandez Muñoz defended successfully her Ph.D. titled "Effects of environmental stochasticity on life history parameters of marine top predators" supervised by Prof. D. Oro.   Well done Noelia !

You can find Noelia's published work here

domingo, 17 de septiembre de 2017

New publication on Tiger Mosquito range expansion !

Tavecchia, G., Miranda, M.-A., Borrás, D., Bengoa, M., Barceló, C. Paredes-Esquivel, C. and Schwarz, C. 2017 Modelling the range expansion of the Tiger mosquito in a Mediterranean Island accounting for imperfect detection   Frontiers in Zoology, 14:39-49 doi. 10.1186/s12983-017-0217-x

Abstract: Aedes albopictus (Diptera; Culicidae) is a highly invasive mosquito species and a competent vector of several arboviral diseases that have spread rapidly throughout the world. Prevalence and patterns of dispersal of the mosquito are of central importance for an effective control of the species. We used site-occupancy models accounting for false negative detections to estimate the prevalence, the turnover, the movement pattern and the growth rate in the number of sites occupied by the mosquito in 17 localities throughout Mallorca Island. Site-occupancy probability increased from 0.35 in the 2012, year of first reported observation of the species, to 0.89 in 2015. Despite a steady increase in mosquito presence, the extinction probability was generally high indicating a high turnover in the occupied sites. We considered two site-dependent covariates, namely the distance from the point of first observation and the estimated yearly occupancy rate in the neighborhood, as predicted by diffusion models. Results suggested that mosquito distribution during the first year was consistent with what predicted by simple diffusion models, but was not consistent with the diffusion model in subsequent years when it was similar to those expected from leapfrog dispersal events. Assuming a single initial colonization event, the spread of Ae. albopictus in Mallorca followed two distinct phases, an early one consistent with diffusion movements and a second consistent with long distance, ‘leapfrog’, movements. The colonization of the island was fast, with ~90% of the sites estimated to be occupied 3 years after the colonization. The fast spread was likely to have occurred through vectors related to human mobility such as cars or other vehicles. Surveillance and management actions near the introduction point would only be effective during the early steps of the colonization.