Publicaciones Científicas

Torres-Porras, J. et al. (2009)

Torres-Porras, J., Carranza, J. & Pérez-González, J. (2009). Combined effects of drought and density on body and antler size of male Iberian red deer (Cervus elaphus hispanicus): implications for climate change prospects. Wildlife Biology 15, 213-221.

Hunting management of red deer Cervus elaphus populations may tend to increase population densities to maximise annual yield. Some studies have shown that density and low winter temperatures affect red deer populations in central and northern Europe, but these results cannot be extrapolated to red deer populations in the Mediterranean region where the limiting season is summer instead of winter. The two regions are predicted to experience different climate change effects: while rainfall may increase in northern latitudes, heavier droughts are expected in the Mediterranean region. We studied red deer populations of different densities on 19 hunting estates in southern Spain during two years with contrasting precipitation levels. Our aim was to quantify the combined effects of drought and population density on the development of stags, which is the main economic objective of hunting management in these areas. We found that drought affected body and antler size negatively, and that the effects were more severe in populations of high density. On the basis of our results, we recommend reducing the current densities of red deer in southern Spain to maintain the economic and environmental sustainability of hunting exploitation in the context of global climate change.

https://doi.org/10.2981/08-059

Pérez-González, J. et al. (2009)

Pérez-González, J., Mateos, C., Carranza, J. (2009). Polygyny can increase rather than decrease genetic diversity contributed by males relative to females: evidence from red deer. Molecular Ecology 18: 1591-1600.

Polygyny is expected to erode genetic variability by reducing the diversity of geneticcontribution of males to the next generation, although empirical evidence shows thatgenetic variability in polygynous populations is not lost as rapidly as expected. We usedmicrosatellite markers to study the genetic variability transmitted by mothers and fathersto offspring during a reproductive season in wild populations of a polygynous mammal,the red deer. Contrary to expectations, we found that males contributed more genetic diversitythan females. Also, we compared study populations with different degrees of polygyny tofind that polygyny was not related to a decrease in genetic diversity contributed by males.On the contrary, when population genetic diversity was relatively low, polygyny associatedwith higher genetic diversity of paternal lineage. Our results show that sexual selection, byfavouring heterozygote individuals, may compensate the potential reduction of effectivepopulation size caused by polygyny, thus contributing to explain why genetic diversity isnot depleted in polygynous systems.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1365-294X.2009.04150.x

Redondo, A. et al. (2009)

Redondo, A., Carranza, J., Trigo, P. (2009). Fat diet reduces stress and intensity of startle reaction in horses. Applied Animal Behaviour Science 118, 69-75.

Intense startle reaction by horses is a common cause of injuries for both riders and horses. Some studies suggest that diet composition, in particular the percentage of fat, may have an effect in stress and behavioural response to novel stimuli. Here we use 28 individual horses to perform an experiment on the influence of diet treatment on physiological parameters and behaviour. We compared a control starch–sugar diet with a diet with higher proportion of fat but the same total energetic content. Physiological and behavioural responses were measured for diet types, both at rest and when exposed to a startling visual stimulus. Our results demonstrate that the increment of fat proportion in the diet reduces the level of stress at resting and the intensity of response to startling stimuli, as denoted both in physiological parameters and in behavioural variables. We conclude that increasing the fat content in diet may be a valuable tool to reduce horse stress and the risk of accidents.

https://www.sciencedirect.com/science/article/pii/S0168159109000355?via%3Dihub

Torres-Porras, J. et al. (2009)

Torres-Porras, J., Carranza, J., Pérez-González, J. (2009). Selective culling of Iberian red deer stags (Cervus elaphus hispanicus) by selective montería in Spain. European Journal of Wildlife Research 55, 117-123

Hunting can affect animal populations not only by increasing mortality but also by introducing selection components associated with particular features of individuals. In addition to the most widespread hunting system in Spain for Iberian red deer stags (Cervus elaphus hispanicus) called montería, there are also selective monterías aimed at culling poor-trophy males in order to improve the average quality of the trophies for commercial hunt. This way of removing poor-trophy males contrasts with the most common procedure of shooting individual males by selective stalking that is used in other areas of Europe. Also, due to the hunting procedure by which most deer are shot while running chased by dogs, it is doubtful whether hunters are actually producing a selective impact on deer populations. In this paper, we compare data of males shot in commercial montería and in selective montería in Southern Spain. We found that males in selective montería were smaller in body size and in antler size than in commercial hunts, even correcting by age, although the selective effect was stronger at some ages. We discuss the implications of this practice for sustainable use and conservation.

https://link.springer.com/content/pdf/10.1007/s10344-008-0225-4.pdf