Foraging and movement paths of female reindeer: insights from fractal analysis, correlated random walks, and Lévy flights

Abstract

Food-plant and foraging-site selection by semidomesticated female reindeer (Rangifer tarandus tarandus L.) was studied to shed light on the searching and foraging behaviour of this herbivore. The aims of the study were (i) to determine the role of food biomass and (or) plant nitrogen content in feeding-site selection and (ii) to analyse the extent to which movement patterns of reindeer are related to availability of food resources using several models of searching behaviour (fractal analysis, correlated random walks, and Lévy flights). The study was conducted in summer 1999 in a mountainous area of northern Sweden. Reindeer selected different plant communities during this period and changed search pattern in late summer. We found that reindeer selected feeding sites with higher green biomass of Betula spp. and Salix spp. However, there was no sharp threshold for foraging as suggested by some models. Contrary to qualitative predictions of optimal-foraging theory, we found no selection of feeding sites on the basis of the nitrogen content of food. The changed search pattern in late summer and the discrepancy between reindeer foraging paths and a correlated random walk model suggests that reindeer were responding to their environment by changing their searching behaviour.

Sensitivity to environmental change of the treeline ecotone and its associated biodiversity in European mountains

“…In the north, reindeer (semi-domesticated and wild) occur regionally in large populations, and throughout history, have profoundly affected the vegetation in their foraging range, including the treeline ecotone vegetation (Oksanen et al 1995, Kashulina et al 1997, Mårell et al 2002, Colpaert et al 2003, Helle & Kojola 2006, Olofsson et al 2009). Reindeer grazing may inhibit tree seedling survival and prevent vegetative regeneration from basal shoots of mountain birch (Kaitaniemi et al 1999, Holtmeier 2002, Cairns & Moen 2004, Neuvonen & Wielgolaski 2005, Solberg et al 2005, and under high reindeer densities, the grazing areas might become increasingly degraded with regard to species diversity and productivity (Kullman 2005, Holtmeier & Broll 2006, Broll et al 2007, Käyhkö 2007, Anschlag et al 2008, Tømmervik et al 2009).…”

Superdiffusive Behavior of Mobile Nodes and Its Impact on Routing Protocol Performance

“…In particular, the so-called Lévy walk model, whose defining characteristics is its super-diffusive property, has been adopted for modeling the movement patterns of living organisms such as Microzooplankton [22], seabirds (albatross) [23], reindeer [24], jackals [25], and monkeys [26], [27], as well as capturing their foraging patterns [28], [29]. Quite recently, the super-diffusive behavior of mobile nodes has also received attention in representing human mobility pattern via a limited number of GPSbased traces [30], [31].…”

Floral Herbivory of Dryas octopetala by Svalbard Reindeer

“…3, 2007, pp. 449-454 E Forage selection by reindeer at landscape level is mainly determined by forage biomass, predation, and insect harassment (Rettie and Messier, 2000;Må rell et al, 2002;Skarin et al, 2004). Once in the vicinity of the experimental plots, reindeer could be attracted to the plots by curiosity or avoid the plots because of a lack of biomass, but forage patch selection is mainly shown to be structured by forage quality, and the experimental plots are too small to alter the food quality of the sites.…”