Factors Affecting Growth and Body Size of Roe Deer

Abstract

Differences in body size of roe deer (Capreolus capreolus) in four study areas in Denmark were investigated in relation to climate, soils, vegetation types and forest cultures, quality of available forage, population density of roe deer, and other environmental factors. Rumen samples, body weights and measurements, reproductive tissues, and lower jaws were obtained from 73 deer during the study. Body weights and measurements and sex and age data were available from several hundred deer from earlier studies. Field-dressed weight, length of the lower jaw, and femur length showed significant differences among the study areas. The largest deer and those with the most rapid growth were from the two areas that had lower soil fertility, lower ratios of agricultural land to the forest area, lower ratios of perimeter to total forest area, and lower densities of deer. Chemical ana]yses of washed and unwashed rumen contents indicated that the forage being consumed by the deer was of essentially equal quality on the four study areas. In Denmark, soil quality appears to be a primary factor determining density of roe deer or biomass but does not appear to directly regulate body size. Body size is most directly related to population density. The mechanisms by wllich density influences body size are apparently social pressures, which affect energy expenditure and food intake, and competition during spring and early summer when foods of high nutritive quality may be limited and physiological demands of the deer are greatest. Regional differences in growth and body size of roe deer have been observed throughout Europe. Selective hunting, practiced for long periods on numerous large estates in Europe, has failed to bring about increases in size of roe deer and their antlers the specific objectives of the prevailing system of game management. Bubenik (19i59), Hennig (1962), Stubbe (1966), Sagesser (1966), and others have described regional differences in body size and antler quality of roe deer. Ueckermann (1957) attempted to relate size differences to forest composition and to-the relationship of forest edge to field. He also emphasized the importance of the characteristics of the substrate as did Hesse (1921) and Sagesser ( 1966 ) . Bubtenik and Bubenik (1967) have pointed to the significance of environmental stress. Little attention, however, has been directed toward the effect of nutrition on the growth and size of roe deer, and little information is available in 1 Present address: Alaska Cooperative Wildlife Research Unit, University of Alaska, College. 64 comparison with the information available for North Ameriean deer. Speeulation by European workers on the possible eauses of regional differences in body size has usually been based on information about only one or a few of the environmental variables that might be involved (for example, vegetative coimposition, substrate, density, and similar factors). Suffieient data have not been available to allow a eonelusive appraisal of the faetors that may influenee body size. This study in Denmark was planned to investigate the influenee of variations in forage quality on the growth and size of roe deer, although it was neeessary to eonsider other faetors of the environment, sueh as vegetative eover types and roe deer density. Because it later beeame apparent that faetors other than forage quality might have a dominant influenee on bo!dy size, the seope of the study was broadened. We aeknowledge the eoolperation and assistanee of Count Ahlefeldt-Bille, J. Due, and P. Thaarup in the use of the study This content downloaded from 157.55.39.215 on Wed, 31 Aug 2016 04:23:09 UTC All use subject to http://about.jstor.org/terms GROWTH AND SIZE OF ROE DEER * Klein and Strandgaard 65 areas. We also appreciate the help of gamekeepers E. Holm and O. Poulsen and foresters O. Jacobsgaard, J. Nielsen, and A. Karlskov. H. Berthelsen did the food habits analyses of the rumen samples and the laboratory work. Chemical analyses of the rumen samples were done by Professor F. Sch,dnheyder and Grete Risgaard at the Department of Biochemistry, University of Aarhus. F. Christoffersen did much of the collecting of the specimen material, and B. Kristiansen assisted in the statistical analyses of the data. Christoffersen, Kristiansen, and J. Andersen were useful sources of information and ideas throughout the study.