Combined Effects of Drought and Density on Body and Antler Size of Male Iberian Red Deer Cervus Elaphus Hispanicus: Climate Change Implications

Abstract

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.

Multiple pathways mediate the effects of climate change on maternal reproductive traits in a red deer population

“…However, local weather variables may be more suitable candidates for drivers of variation, not least because it is generally easier to interpret the mechanisms underlying their effects, and because these effects are not complicated by varying associations between local conditions and large-scale indices (e.g., see discussions in Pettorelli et al 2006, Martinez-Jauregui et al 2009, van de Pol et al 2013. Previously, the effects of climate change on the Rum study population have been examined using ''growing degree-days'' (GDD), the cumulative sum of the daily mean temperatures above a threshold during a given period, as a measure of climate, assuming a relevant temperature threshold for GDD of 58C (Moyes et al 2011).…”

“…These tests were done within a linear model framework with no other fixed effects included. The start date and duration (width) of the window was then varied, and the consequent strength of associations with the trait was recalculated in order to identify the critical time window that had the greatest association with trait expression (van de Pol and Cockburn 2011).…”

“…For example, warmer temperatures have been associated with both increased and decreased body size in northern ungulate populations, depending on the time of year considered Stenseth 1999, Weladji andHoland 2003). Therefore identifying the critical time windows during which different environmental cues affect trait expression is crucial for understanding phenological changes (van de Pol and Cockburn 2011). Herbivores are likely to be both directly influenced by climatic conditions through energy demands and indirectly influenced through plant productivity (Saether 1997, Stenseth et al 2002, Forchhammer and Post 2004.…”

“…Therefore, the multiple pathways via which the environment influences herbivore ecology potentially can make it challenging to identify drivers of environmental change (Mysterud et al 2008, Martinez-Jauregui et al 2009). Further, observed changes in phenotypic traits need to be considered in the context of changes in population demography such as population density and age structure (whether occurring independently or as a direct or trait-mediated effect of environmental change), because these can potentially reinforce or dampen climatic effects on traits (Torres-Porras et al 2009, Ozgul et al 2010, van de Pol et al 2012.…”

Morphometric characterization of Mesola red deerCervus elaphus italicus(Mammalia: Cervidae)

“…Langvatn 1986). In particular, while some studies have been carried out on populations from central-northern Europe, information is scarce for red deer living in southern Europe (Mattioli 1993;Azorit et al 2002;Mattioli et al 2003;Martıńez et al 2005;Torres-Porras et al 2009). Thus, the variability of this species in morphological and biometric features still remains poorly known.…”