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Rainfall predicts seasonal home range size variation in nyala
Author(s) -
Janse van Rensburg Jeanrick,
McMillan Michael,
Giżejewska Aleksandra,
Fattebert Julien
Publication year - 2018
Publication title -
african journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.499
H-Index - 54
eISSN - 1365-2028
pISSN - 0141-6707
DOI - 10.1111/aje.12455
Subject(s) - variation (astronomy) , range (aeronautics) , content (measure theory) , geography , home range , mathematics , statistics , econometrics , ecology , biology , physics , astrophysics , engineering , mathematical analysis , aerospace engineering , habitat
Optimal foraging theory posits that animals should minimize the size of their home range—the area used to meet their requirements (Burt, 1943)—around limiting resources (Ford, 1983). Hence individuals ranging in less productive habitats or exploiting patchy resources have larger home ranges (Ford, 1983), and spatio-temporal variations in resource availability can lead to changes in home range size (Fattebert, Baubet, Slotow, & Fischer, 2017; van Beest, Rivrud, Loe, Milner, & Mysterud, 2011). In nyala (Tragelaphus angasii), a mixed-feeder antelope, the effects of habitat variability on ranging and space use patterns are poorly understood (Kirby, Shannon, Page, & Slotow, 2008; Labâo-Tello & van Gelder, 1975). A better understanding of the drivers affecting ranging patterns in nyala would help the design of evidence-based habitat management strategies. In this highly dimorphic, polygynous species, males are expected to have larger home ranges than the females because of size-dependant metabolic rates (McNab, 1963). In polygynous species, females are expected to secure access to limiting resources through optimal foraging to successfully raise offspring, while males are expected to range more widely in order to increase mating opportunities with numerous females (Clutton-Brock, 1989; Fattebert et al., 2016). In the rain season, vegetation becomes more palatable with higher protein contents (Duncan & Poppi, 2008), and together with abundance of surface water, this should lead to a reduction of home range size (Bowers, Welch, & Carr, 1990). Alternatively, in the dry season, although food resources are more dispersed, scarcity of surface water could constrain ranging patterns around permanent surface water (Smit, Grant, & Whyte, 2007). We investigated seasonal variations of space use patterns in nyala, and tested the effects of sex, and rainfall as a metric of seasonal variability on home range size.