David R. Klein

Carbon/nutrient balance of boreal plants in relation to vertebrate herbivory

The evolutionary response of plants to herbivory is constrained by the availability of resources in the environment. Woody plants adapted to low-resource environments have intrinsically slow growth rates that limit their capacity to grow rapidly beyond the reach of most browsing mammals. Their low capacity to acquire resources limits their potential for compensatory growth which would otherwise enable them to replace tissue destroyed by browsing. Plants adapted to low-resource environments have responded to browsing by evolving strong constitutive defenses with relatively low ontogenetic plasticity. Because nutrients are often more limiting than light in boreal forests, slowly growing boreal forest trees utilize carbon-based rather than nitrogen-based defenses. More rapidly growing shade-intolerant trees that are adapted to growth in high-resource environments are selected for competitive ability and can grow rapidly beyond the range of most browsing mammals. Moreover, these plants have the carbon and nutrient reserves necessary to replace tissue lost to browsing through compensatory growth. However, because browsing of juvenile plants reduces vertical growth and thus competitive ability, these plants are selected for resistance to browsing during the juvenile growth phase. Consequently, early successional boreal forest trees have responded to browsing by evolving strong defenses during juvenility only. Because severe pruning causes woody plants to revert to a juvenile form, resistance of woody plants to hares increases after severe hare browsing as occurs during hare population outbreaks. This increase in browsing resistance may play a significant role in boreal forest plant-hare interactions. Unlike woody plants, graminoids retain large reserves of carbon and nutrients below ground in both low-resource and high-resource environments and can respond to severe grazing through compensatory growth. These fundamental differences between the response of woody plants and graminoids to vertebrate herbivory suggest that the dynamics of browsing systems and grazing systems are qualitatively different.

Ecological Dynamics Across the Arctic Associated with Recent Climate Change

Assessing the Arctic The Arctic is experiencing some of the most rapid climate change currently under way across the globe, but consequent ecological responses have not been widely reported. At the close of the Fourth International Polar Year, Post et al. (p. 1355) review observations on ecological impacts in this sensitive region. The widespread changes occurring in terrestrial, freshwater, and marine systems, presage changes at lower latitudes that will affect natural resources, food production, and future climate buffering. At the close of the Fourth International Polar Year, we take stock of the ecological consequences of recent climate change in the Arctic, focusing on effects at population, community, and ecosystem scales. Despite the buffering effect of landscape heterogeneity, Arctic ecosystems and the trophic relationships that structure them have been severely perturbed. These rapid changes may be a bellwether of changes to come at lower latitudes and have the potential to affect ecosystem services related to natural resources, food production, climate regulation, and cultural integrity. We highlight areas of ecological research that deserve priority as the Arctic continues to warm.

The introduction, increase, and crash of reindeer on St. Matthew Island.

Reindeer (Rangifer tarandus), introduced to St. Matthew Island in 1944, increased from 29 animals at that time to 6,000 in the summer of 1963 and underwent a crash die-off the following winter to less than 50 animals. In 1957, the body weight of the reindeer was found to exceed that of reindeer in domestic herds by 24 53 percent among females and 46 61 percent among males. The population also responded to the high quality and quantity of the forage on the island by increasing rapidly due to a high birth rate and low mortality. By 1963, the density of the reindeer on the island had reached 46.9 per square mile and ratios of fawns and yearlings to adult cows had dropped from 75 and 45 percent respectively, in 1957 to 60 and 26 percent in 1963. Average body weights had decreased from 1957 by 38 percent for adult females and 43 percent for adult males and were comparable to weights of reindeer in domestic herds. Lichens had been completely eliminated as a significant component of the winter diet. Sedges and grasses were expanding into sites previously occupied by lichens. In the late winter of 196364, in association with extreme snow accumulation, virtually the entire population of 6,000 reindeer died of starvation. With one known exception, all of the surviving reindeer (42 in 1966) were females. The pattern of reindeer population growth and die-off on St. Matthew Island has been observed on other island situations with introduced animals and is believed to be a product of the limited development of ecosystems and the associated deficiency of potential populationregulating factors on islands. Food supply, through its interaction with climatic factors, was the dominant population regulating mechanism for reindeer on St. Matthew Island. St. Matthew Island, 128 square miles in area and located in the Bering Sea Wildlife Refuge in the north central Bering Sea (Fig. 1), supports a poorly developed land fauna. Native land mammals are restricted to a vole (Microtus abbreviatus) and the arctic fox ( Alopex lagopus ), although a resident population of polar bears (Thalarctos maritimus) existed there in Recent times (Elliot 1882). The reindeer on St. Matthew Island were the result of the release of 24 females and 5 males on August 20, 1944, by the U. S. Coast Guard (Klein 1959). Shortly afterwards, the Coast Guard loran station on the island was abandoned and the island has been uninhabited since then. Specimens taken for study purposes and those shot by Coast Guard personnel as a recreational pursuit have been the only harvest from the herd. With the exception of 10 in 1966, these were all taken during 1957-63 and totaled 105 animals. This paper reports on the population dynamics and range interrelationships of this island reindeer herd from the time of introduction through its rapid increase and crash die-off until July, 1966. I appreciate the field cooperation of colleagues Dr. Francis H. Fay, Dr. Vernon L. Harms, Jack Manley, and Gerry Cowan and the assistance of James Whisenhant and Dr. Detlef Eisfeld. Dr. Eisfeld also did the analyses of the reindeer ovarian material and, through discussion, provided useful suggestions for the interpretation of the data. Sam Harbo provided advice in the statistical treatment of data.

Range-Related Differences in Growth of Deer Reflected in Skeletal Ratios

The skeletal ratio femur/hind foot was employed to identify growth differences existing between two island populations of deer ( Odocoileus hemionus sitkensis ) in southeast Alaska. Skeletal ratios are a more reliable measure of growth differences than measurements of body weight or length because the skeleton can be measured more accurately. Also, the differential growth of skeletal parts reflects physiological age essentially independently of body size; therefore, the skeletal ratio is not as greatly influenced by genetic differences as are measurements of body weight and length. The deer populations on the islands studied show growth differences which are apparently attributable to differing levels in their annual nutrition. The use of the femur/hind foot ratio supports the thesis that these growth differences are of nutritional rather than genetic origin.

Variation in quality of caribou and reindeer forage plants associated with season, plant part, and phenology

Plant parts used as forage by caribou and reindeer (Rangifer tarandus) have been collected in conjunction with studies of foraging dynamics, nutrition, growth, and population ecology of this arctic ungulate over the course of several years in Alaska and other circumpolar areas. These samples were subjected to proximal analyses for percent nitrogen, phosphorus, sodium, carbohydrate, cell wall (NDF), acid detergent fiber (ADF), lignin, cellulose, and residual ash, and treated to determine in vitro and nylon bag dry matter digestibility (DMD). Among winter vascular plant forage only carbohydrates showed a positive correlation with digestibility, wheras in summer nitrogen, phosphorus, and in some cases sodium, also are positively correlated with digestibility. Forage from shrubs and forbs in early summer had higher nitrogen and carbohydrate levels than later in the season, wheras graminoids show an increase in these levels during the first few weeks of growth. Floral parts during anthesis showed higher nitrogen, phosphorus, and carbohydrate levels and higher digestibility than corresponding leaf material. The annual dietary cycle is the product of adjustment of the physiological cycle to seasonal fluctuation in forage quality and quantity.

Caribou calf production and seasonal range quality during a population decline

To address the importance of winter and summer ranges to the productivity of caribon (Rangifer tarandus) we studied the Southern Alaska Peninsula Caribon Herd (SAPCH). The SAPCH declined by >80% between 1983 and 1993, and concurrently experienced a decline in July calf:cow ratios from 33:100 preceding the population peak in 1983 to 14:100 in recent vears. The SAPCII comprises 2 groups that use distinct seasonal ranges, and calf production was consistently higher in 1 group from 1989 to 1992. We hypothesized that higher productivity in that group was related to greater availability and quality of forage on either its winter or summer ranges, or both Whereas lichens were scarce throughout the SAPCII range, lichen biomass, cover, and gross energy content ( kJ/g) were lower on the winter range of the more productive group. In contrast, herbaceous forage was more abundant on the summer range of the more productive group here the plant growing season commenced 1 month before calving and lasted nearly I month longer compared to the summer range of the less productive group. Finally, during the 1992 calving season, gray wolves (Canis lupus) and brown bears (Ursus arctos occurred with equal frequency on eacl range. Thus, lo productivity in the SAPCH may have been influenced by scarcity of lichens on winter ranges, but differences in productivity between the group were apparently related to quality of summer ranges. We suggest that lower productivity in 1 group reflects greater perinatal mortality of weak calves born to females that were unable to make summer gains in body condition before moving onto winter rang with low lichen availability.

Factors Affecting Growth and Body Size of Roe Deer

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.

Decrease of lichens in Arctic ecosystems: the role of wildfire, caribou, reindeer, competition and climate in north-western Alaska

We review and present a synthesis of the existing research dealing with changing Arctic tundra ecosystems, in relation to caribou and reindeer winter ranges. Whereas pan-Arctic studies have documented the effects on tundra vegetation from simulated climate change, we draw upon recent long-term regional studies in Alaska that have documented the actual, on-the-ground effects. Our review reveals signs of marked change in Arctic tundra ecosystems. Factors known to be affecting these changes include wildfire, disturbance by caribou and reindeer, differential growth responses of vascular plants and lichens, and associated competition under climate warming scenarios. These factors are interrelated, and, we posit, unidirectional: that is, they are all implicated in the significant reduction of terricolous lichen ground cover and biomass during recent decades. Lichens constitute the primary winter forage for large, migratory caribou and reindeer herds, which in turn are a critical subsistence resource for rural residents in Alaska. Thus, declines in these lichens are a major concern for rural people who harvest caribou and reindeer for subsistence, as well as for sport hunters, reindeer herders, wildlife enthusiasts and land managers. We believe a more widely distributed and better integrated research programme is warranted to quantify the magnitude and extent of the decline in lichen communities across the Arctic.

Comparative response of Rangifer tarandus and other northern ungulates to climatic variability

To understand the factors influencing life history traits and population dynamics, attention is increasingly being given to the importance of environmental stochasticity. In this paper, we review and discuss aspects of current knowledge concerning the effect of climatic variation (local and global) on population parameters of northern ungu¬lates, with special emphasis on reindeer/caribou (Rangifer tarandus). We also restrict ourselves to indirect effects of climate through both forage availability and quality, and insect activity. Various authors have used different weather variables; with sometime opposite trends in resulting life history traits of ungulates, and few studies show consistent effects to the same climatic variables. There is thus little consensus about which weather variables play the most sig¬nificant role influencing ungulate population parameters. This may be because the effects of weather on ungulate pop¬ulation dynamics and life history traits are scale dependent and it is difficult to isolate climatic effects from density dependent factors. This confirms the complexity of the relationship between environment and ecosystem. We point out limits of comparability between systems and the difficulty of generalizing about the effect of climate change broadly across northern systems, across species and even within species. Furthermore, insect harassment appears to be a key climate-related factor for the ecology of reindeer/caribou that has been overlooked in the literature of climatic effects on large herbivores. In light of this, there is a need for further studies of long time series in assessing effects of climate variability on reindeer/caribou.

Reaction of Reindeer to Obstructions and Disturbances

In Scandinavia, highways and railroads have not generally created obstructions to the movement of domesticated reindeer, although thousands of animals are killed each year in accidents. Some disruption in the movements of wild reindeer in Norway has been associated with the construction of a railroad and highway through an alpine plateau south of Trondheim. Hydroelectric projects have had the greatest detrimental effects on reindeer by flooding rangelands and obstructing migration routes. Special problems are created by the fluctuating water levels in reservoirs and rivers; efforts to mitigate the effects of these fluctuations have been only partially successful. Reindeer have strong traditions for migrating along specific routes, and realignment of these routes is extremely difficult. Conflicts of interest exist between reindeer herders and foresters. During their winter feeding, the deer damage young trees. The cutting of forests usually results in a deterioration of the area as a rangeland for reindeer. Herbicides used in forestry have been implicated in the death of some reindeer in Sweden, and research is now under way to determine the effects of herbicides on reindeer. The increased use of fences in reindeer husbandry in Scandinavia has emphasized the fact that reindeer behavior and characteristics of the terrain must be considered if fences are to be successful in directing or controlling the movements of reindeer. Herders now use snowmobiles instead of reindeer for transportation and herding, but the machines disturb the reindeer and must be used with discretion. Recent evidence indicates that large amounts of industrial waste in the atmosphere are carried from the British Isles and central Europe to Scandinavia, where they fall out in rain and snow. This has raised concern about the influence of the wastes on lichens, the main winter food supply of reindeer. Studies are now under way in Finland, Sweden, and Norway, through the International Biological Program, to determine the growth rates of the several lichen species that are important to reindeer.