Life‐history variation of wild reindeer (Rangifer tarandus) in the highly productive North Ottadalen region, Norway

Abstract

Variation in life history is a central key to understanding population dynamics, and density dependence and climate are important factors in shaping life-history variation in ungulates. Early growth is often sensitive to adverse conditions and this may in turn affect juvenile survival and age at first reproduction. We report variation in body weight of 5079 reindeer Rangifer tarandus from North Ottadalen, a very productive reindeer area in Norway, sampled over 14 years in the period 1967-1989. The North Ottadalen reindeer herd was established in 1964 from a winter herd of some 500 semi-domestic reindeer, and allowed to grow to a peak of over 3300 reindeer in 1974, after which increased harvest decreased the population size. The proportion of lactating yearling females varied between 0% and 50%. Lactating females had lower autumn body weights than non-lactating females. A decline in body weight with age, i.e. senescence, was evident in both males and females from around 7 to 9 years of age. Body weights of all age and sex groups as well as the proportion of yearling females lactating decreased over time, and more so in younger than older males, although the population size declined markedly after the population peak in 1974. We found no effect of the North Atlantic Oscillation or local weather on body weight. The possible causes of the marked decline in performance with time in the North Ottadalen reindeer herd are discussed, and it is suggested that this may be related to the transition from being managed as semi-domestic to wild (i.e. hunted).

Heterogeneity in individual quality overrides costs of reproduction in female reindeer

“…Extensive evidence for individual variation in the quality of female mammals and birds has been reported (Cobley et al 1998;Festa-Bianchet 1998;Gaillard et al 1998;Pomeroy et al 1999;Crocker et al 2001;Tavecchia et al 2005). Early reproduction has, however, been reported to be costly in several birds (Pyle et al 1997;Barbraud and Weimerskirch 2005), female squirrels (Descamps et al 2006), female reindeer breeding as calves (Reimers et al 2005), and male Soay sheep breeding as lambs (Robinson et al 2006). We also found a marked eVect of experience as the weaning success peaked for multiparous females, being lowest for Wrst-time breeders (Forslund and Pärt 1995;Weladji et al 2006).…”

“…Moreover, we also found female survival to decrease with delayed age at primiparity. Such a relationship is expected to occur when age at primiparity is delayed because of poor condition (Skogland 1983), given the positive relationship between body mass and age, especially among nulliparous females (Rönnegård et al 2002;Reimers et al 2005). Since the probability of producing a calf is closely associated with body mass in reindeer (Reimers 1983), and that age and size at maturity both determine age at primiparity of females in a given population (RoV 1992) our Wndings may be attributed to variation in individual quality (see also Barbraud and Weimerskirch 2005).…”

Climatic effects on life-history traits of moose in Estonia

“…Although the Durbin-Watson statistic did not detect any signiWcant autocorrelation in the residuals of our models (Statistica 7.0), we still observed some trends in density (r = ¡0.34) and MIE (r = ¡0.27). Hence, "year" as a covariate is a regression component that was used to correct for any time trends in predictors, while "year" as a random factor was used to account for the annual Xuctuations that reXect additional variation independently of the trend (see Reimers et al 2005). The signiWcance of explanatory terms and interactions was assessed when Wtted last in the model using type 1 (sequential) sum of squares.…”

Environment during the Middle to Late Palaeolithic transition in southern France: The archaeological sequence of Tournal Cave (Bize-Minervois, France)

“…Klein (1968) and Skogland (1983Skogland ( , 1985 reported effects of overgrazing on reindeer population and body sizes. According to numerous ecological studies (Reimers, 1984;Skogland, 1984Skogland, , 1989Fancy and White, 1987;Klein et al, 1987;Collins and Smith, 1991;Kuzyk et al, 1999;Moen Heggberget et al, 2002;Weladji et al, 2002;Weladji and Holand, 2003;Weladji et al, 2003aWeladji et al, , 2003bKojola et al, 2004;Chan et al, 2005;Pettorelli et al, 2005;Reimers et al, 2005;Loe et al, 2007) the major causes of these fluctuations must be identified in the light of the many parameters influencing the life history traits of R. tarandus. These agents can be classified into two categories: abiotic factors related to topography, geography and climate; and biotic factors related to competition and foraging behaviour.…”