animal perception of seasonal thresholds changes in elephant movement in relation to rainfall patterns动物的看法季节性阈值象运动与降雨模式的变化.pdfVIP

Animal Perception of Seasonal Thresholds: Changes in Elephant Movement in Relation to Rainfall Patterns 1 1¤ 2 1,3 1 Patricia J. Birkett *, Abi T. Vanak , Vito M. R. Muggeo , Salamon M. Ferreira , Rob Slotow 1 Amarula Elephant Research Programme, School of Life Sciences, University of Kwazulu-Natal, Durban, South Africa, 2 Dipartimento di Scienze Statistiche e Matematiche ` ‘Vianelli’, Universita di Palermo, Palermo, Italy, 3 Scientific Services, Kruger National Park, Skukuza, South Africa Abstract Background: The identification of temporal thresholds or shifts in animal movement informs ecologists of changes in an animal’s behaviour, which contributes to an understanding of species’ responses in different environments. In African savannas, rainfall, temperature and primary productivity influence the movements of large herbivores and drive changes at different scales. Here, we developed a novel approach to define seasonal shifts in movement behaviour by examining the movements of a highly mobile herbivore (elephant; Loxodonta africana), in relation to local and regional rainfall patterns. Methodology/Principal Findings: We used speed to determine movement changes of between 8 and 14 GPS-collared elephant cows, grouped into five spatial clusters, in Kruger National Park, South Africa. To detect broad-scale patterns of movement, we ran a three-year daily time-series model for each individual (2007–2009). Piecewise regression models provided the best fit for elephant movement, which exhibited a segmented, waveform pattern over time. Major breakpoints in speed occurred at the end of the dry and wet seasons of each year. During th