Exploring the Impact of Contextual Variables on the Temporal Variability of Grazing and Risk Avoidance Patterns of Red Deer (Cervus elaphus) in an Alpine Environment
Project Number: CH-6096
||03/01/2016 - 05/31/2017 project completed
||Universität Zürich, Geographisches Institut
||Prof. Robert Weibel
Geographic Information Systems
Geographisches Institut - Geographic Information Systems
Phone: +41 (0) 44 635 51 90 ; +41 (0) 44 635 51 11
FAX: +41 (0) 44 635 68 48
Red Deer, cervus elaphus
The behaviour of red deer (Cervus elaphus) is largely determined by a trade-off between forag- ing and predator avoidance. Predator avoidance frequently manifests itself in the use of both structural and non-structural cover, which conceals the prey from the predator. In a heteroge- neous landscape, the spatial distribution and availability of these elements of cover are subject to change over time, especially when migratory movements are considered.
In this thesis, the importance of this trade-off is investigated by linking the space use of red deer in the Lower Engadine valley of Switzerland to contextual variables. To this end, the mi- gration patterns of 16 red deer were first investigated by combining Minimum Convex Polygons (MCPs) and Kernel Density Estimation (KDE), which provided the basis for further inspections. Subsequently the temporal variability of diurnal activity levels were investigated by means of cre- puscularity and diurnality indices and linked to the ecology of deer. The temporal variability of the importance of structural and non-structural cover was analysed mainly in relation to forested areas and shrublands, which constitute a crucial habitat characteristic for red deer. Lastly in rela- tion to grazing activity, the spatio-temporal patterns of locations were investigated at core grazing sites and analysed with respect to forage quality and risk avoidance strategies.
Results showed, that the extent of migratory movements of the studied individuals varied greatly, supporting the notion that migration is a phenomenon that should be placed on the resident-migratory continuum rather than classified in a binary fashion. The exploration of an- nual variations in activity levels showed a distinct preference of crepuscular activity which per- sisted throughout the year. Diurnal activity showed much greater annual fluctuations, with a general preference of night-time activity in spring, autumn, and winter and a daytime preference in summer months. The possibility of anthropogenic influences on diurnal activity patterns are discussed. The central importance of forested areas and shrublands as elements of cover were largely confirmed, though their importance varies both in the course of the year and at different times of the day. The decrease in preferential selection of forests found in summer months is most likely linked to intensified foraging behaviour in open landscapes and a decrease in human disturbance in mountainous regions. On the other hand, a decrease in preferential selection of shrublands in winter was sought to be related to declining forage availability due to snow cover. Investigation of grazing activity showed that at sites associated with winter home ranges, posi- tions in open landscapes occurred mostly during the hours of darkness, providing indications of human disturbance influencing the behaviour of deer. At such sites associated with summer home ranges, the risk avoidance strategies seem to manifest themselves in an increased distance to hiking trails during the day, as the higher quality forage was of mountain pastures was typically only accessed during the night. Results further suggest that red deer do not seek areas which are invisible from hiking trails during the day.
Patrick, James (2017) Exploring the Impact of Contextual Variables on the Temporal Variability of Grazing and Risk Avoidance Patterns of Red Deer (Cervus elaphus) in an Alpine Environment. Master Thesis, University of Zurich. PDF Masterarbeit
Last update: 4/13/18
Source of data: ProClim- Research InfoSystem (1993-2020)
Update the data of project: CH-6096