Effects of human disturbance on the diet composition of free ranging animals

Effects of human disturbance on the diet composition of wild red deer (Cervus elaphus)

Sevvandi Jayakody, Angela M. Sibbald, Robert W. Mayes, Russell J. Hooper, Iain J. Gordon and Xavier Lambin

EUROPEAN JOURNAL OF WILDLIFE RESEARCH

Volume 57, Number 4, 939-948, 

 

Increasing disturbance in wilderness areas in the form of tourism related activities is a cause of concern.

 In this paper the authors analyze human recreational activities and its effect on the nutrition of free-ranging herbivores due to trade-offs between feeding in preferred habitats and perceived predation risk.

The researchers estimated diet composition for red deer in the Scottish highlands in spring, when recreational activity is high, and in winter when it is at lower level. Faecal samples from three habitat types, grassland, heather moorland and woodland, were collected at sites close to a busy track . Samples were also collected from less disturbed areas also.

The diet consisted of 39% grasses, sedges, herbs and rushes (GSHR) and 58% Calluna vulgaris and Erica spp.  in spring, against 14% grasses and 77% heather in winter, with small quantities of Vaccinium spp and Pinus sylvestris (tree) in both seasons.

In spring, faeces from disturbed grass and woodland sites indicated a diet with less GSHR and more heather and tree than faeces from less-disturbed sites. The authors say this could be due to an increased need for vigilance in exposed grassland and the need to seek cover. Faeces from all disturbed sites in winter indicated a diet with more GSHR and less heather than faeces from less-disturbed sites. It is presumed that this could be due to a seasonal decline in recreation and increase in hunting activity reversing the disturbance levels at the different sites. Hunting is not normally carried out in areas used by the public for recreation.

The authors conclude that nutritional benefits may accrue to deer if disturbance near open grassland are brought down.