Friday, 11 January 2019

New Publication on Vulture, farming practices and diseases !

Blanco, G., Cortés-Avizanda, A., Frias, Ó., Arrondo, E., Donázar, J.A. 2019 Livestock farming practices modulate vulture diet-disease interactions Global Ecology and Conservation. doi: 10.1016/j.gecco.2018.e00518

Photo. A.Cortes-Avizanda,M. de la Riva, R. Sanchez-Carrion
Abstract: Low- and high-intensity farming exert different direct and indirect effects on vulture populations by driving the availability, exploitation and characteristics of carrion. This is especially true for the levels of pharmaceuticals in wild and domestic animal carcasses. However, the impact of farming systems on the diet-related health of avian scavengers remains unclear. Here, we evaluate diet and disease signs in nestlings of three European species of vultures (Cinereous, Aegypius monachus, Griffon, Gyps fulvus, and Egyptian, Neophron percnopterus), living in different regions of Spain under contrasting farming schemes.
We test the hypothesis that disease (oral mucosal lesions caused by mixed fungal and bacterial infections) in vultures is influenced by features of food and foraging conditions derived from farming systems, especially due to the expected chronic and irregular ingestion of pharmaceuticals under intensive (factory farms) compared to extensive systems. A large proportion of nestlings of the three vulture species in central Spain (high-intensity farming area) continue to be affected by oral lesions (cinereous: 75%, n = 16; griffon: 61%, n = 28; Egyptian: 46%, n = 13). The same type of lesions, at a much lower frequency, was found in nestling of the three vulture species in each of the selected areas corresponding to low-intensity farming areas in southern and northern Spain (Cinereous: 39%, n = 13; Griffon: 7%, n = 14; Egyptian: 6%, n = 17). As predicted, a positive relationship was found between the proportion of nestlings with lesions and the frequency of intensive livestock from factory farms (swine and poultry) in the diet. The intensive medication in factory farms deserves further research to assess its implications in vulture diet-disease interactions at large geographical scales. Assessing the presence of oral lesions as an indicator of physiological alterations is encouraged along with pharmacovigilance in surveillance programs aimed at evaluating the direct and indirect effects of livestock farming practices on vulture health. Given the increasing exploitation of domestic instead of wild animals by vultures, the growth in high-intensity farming and the medication practices in free-ranging and semi-extensive farming systems, this assessment would help to characterize the risks associated with different farming operations for wildlife. This evaluation is crucial to avoid exacerbating the detrimental consequences of supplementary feeding programs contrary to their primary aim of the conservation of endangered species.



Friday, 4 January 2019

New Publication on Woodcock mortality and hunting pressure

Prieto, N., Tavecchia, G., Telletxea, I, Ibañez, R., Ansorregi, F., Galdos, A., Urruzola, A., Iriarte, I. and Ariziaga, J. 2019 Survival probabilities of wintering Eurasian Woodcocks Scolopax rusticola in northern Spain reveal a direct link with hunting regimes. J. Ornithol. doi: 10.1007/s10336-018-1617-1
From en.wikipedia.org
Abstract  The management of game species relies on robust estimates of hunting-related mortality. A relative measure of this mortality can be obtained by comparing survival estimates of animals across similar areas with different hunting pressures. We conducted live recapture-dead recovery analyses on wintering Eurasian Woodcocks Scolopax rusticola (hereinafter “Woodcock”) in provinces of Gipuzkoa (GIP) and Álava (ALA), two neighboring regions of northern Spain. The two regions have a similar number of hunting licences issued on a per day basis, but while hunting is limited to 3days per week in ALA, in GIP it is allowed on a daily basis, resulting in a ca. 50% longer period of  exposure of game species to hunting-related mortality here.We used a model based on monthly survival estimates to test whether the mortality of Woodcock varied between the two regions. Mean (± SE from a time-constant model) annual survival of Woodcocks was estimated to be 0.37 (± 0.04) and 0.56 (± 0.04) in GIP and ALA, respectively. If we assumed that this difference was only due to the longer period of exposure to hunting, mortality was increased by ca. 10% per additional day of hunting per week. Moreover, we also found that survival was positively associated with temperature in one of the study zones (ALA), suggesting that a high hunting pressure can override the effect of climate-dependent fluctuations. However, further research into fecundity and dispersal is necessary to assess the viability and sustainability of the wintering Woodcock populations under the current hunting regimes in these two zones.
 

Monday, 31 December 2018

News: APHIS and snakes in Ibiza

The research by A. Rotger Vallespir had make the news here and here. Andreu showed how the scale pattern on the head of the snake Hemorrhois hippocrepis changes across individuals and it can be used as a fingerprint to track individual and assess their life-history. The free available software APHIS, developped by the GEDA in 2015, can be used to process the images. Andreu's research was first presented at the VII Conference on Balearic Environment early this month.
You can find the IMEDEA press release here



Wednesday, 26 December 2018

News: Parasites and Storm Petrel!


The research led by A. Sanz-Aguilar of the GEDA en collaboration with the Department of Zoology of the UIB is on the news here (an article by J. M. L. Romero on the Diario de Ibiza)

Ana is studying whether differences in the fledgling sucess among the different parts of the colony can be due to the presence of specific parasites (Ornithodoros maritimus). The results was presented at the VII Conference on Baelaric Enviroment early this month.




Wednesday, 19 December 2018

Most cited paper in Ardeola !

Photo: M Gomila
The work by A. Cortés-Avizanda of the GEDA on the ecological role of raptors published in Ardeola in 2016 (here) was the most cited period in the last 3-year period. 
Congrats Ainara (& Co.)!

Monday, 17 December 2018

GEDA at the VII Conference on Balearic Environment


 The GEDA participated at the VII Balearic Environmental Conference on Mallorca and Ibiza presenting the studies on lizards, vultures, shearwaters and storm petrels.

 






Tuesday, 4 December 2018

New Publication on modelling transient probability!

Sanz-Aguilar, A., Pradel, R. and Tavecchia, G. 2018 Age-dependent capture-recapture models and unequal time intervals. Animal Biodiversity and Conservation 42 (1), pag. 91-98


Photo: M. Gomila
Abstract:Estimates of survival probabilities in natural populations can be obtained through capture–mark–recapture (CMR) models. However, when capture sessions are unevenly spaced, age–dependent models can lead to erroneous estimates of survival when individuals change age class during the time interval between two capture occasions.
We propose a solution to correct for the mismatch between time intervals and age class duration in two age class models. The solution can be implemented in different ways. The first consists of adding dummy occasions to the encounter histories and fixing the corresponding recapture probabilities at zero. The second makes use of the log–link function available in some CMR software (e.g. program MARK). We used simulated and real data to show that the proposed solution delivers unbiased estimates of age–dependent survival probabilities.

New Publication on Vulture, farming practices and diseases !

Blanco, G., Cortés-Avizanda, A., Frias, Ó., Arrondo, E., Donázar, J.A. 2019 Livestock farming practices modulate vulture diet-disease inter...