Factors Affecting Wolf-Elk Interactions in the Greater Yellowstone Area
Creel, S.; Winnie, J.; Christianson, D., Rocky Mountain Wolf Recovery 2003 Annual Report
This project focuses on measuring behavioral responses of elk to the risk of predation by wolves, and determining the consequences of behavioral responses for elk physiology, demography and population dynamics. Using custom-built GPS collars, we have collected 18,317 unbiased locations for adult elk in four drainages of the Greater Yellowstone Ecosystem. These data reveal significant changes in use of the landscape on days that wolves are present within a drainage, relative to days when wolves are absent. Changes in landscape use are driven primarily by changes in the behavior of bulls, while cows show less response. This sex-difference is as predicted, because analysis of 51 wolf kills on our site reveals that bulls and calves are taken significantly more often than predicted if prey were selected at random, while cows are taken less often than expected. Herd sizes also shift on days that wolves are in a drainage, dropping significantly...in the presence of wolves. This suggests that grouping in response to predation risk does not benefit elk (for example via the "many eyes" effect). Instead, the bulk of our data suggest that behavioral responses by elk are aimed at reducing the likelihood of being detected by wolves, rather than altering the outcome following detection. This interpretation is reinforced by data on herd size in relation to distance to obstructive cover. In general, herd size increases as distance to cover increases. However, there is a significant interaction between the distance to cover and the presence of wolves in their effects on herd size. Aggregation far from cover occurs only when wolves are absent. When wolves are present, elk remain in small herds at all distances to cover. This pattern strongly suggests that aggregation on open (grass) plant communities is a foraging response during periods of low predation risk, rather than an antipredator response during periods of high risk. The behavior of individual elk also responds to the presence of wolves within a drainage. Using scan sampling to record 10,642 observations, contingency tables reveal that the presence of wolves within a drainage on the day of observation is associated with an increase in vigilance, with a decrease in foraging and a decrease in movement. The proportion of time bedded did not change significantly, probably in part because this was not a common behavior. These data show that elk behave differently on days that wolves are present within their drainage, but they do not demonstrate that behavioral responses carry costs. We are less advanced in analyses of the costs of antipredator responses, but we have recorded reduced rates of pregnancy (61-85% for a low predation site and 21% for a high predation site) for herds exposed to wolf predation, while pregnancy rates remained high (84-100%) on two nearby sites with little wolf activity. Data from more years are needed. Trends in population size (by aerial total count) and recruitment (from ground and aerial classification counts) suggest that predation (both direct and indirect effects) may be altering elk demography and dynamics. Recruitment in early winter has been at or below 20 calves:100 cows on 5 of 6 winters with data since colonization by wolves, compared to 1 of 13 winters prior to wolf colonization. Similarly, population size has been below 1500 elk in 6 of 7 winters since wolf colonization, compared to 16 of 41 winters prior to wolves. Recall that factors other than wolves contribute to these patterns.
Factors Affecting Wolf Distribution, Numbers, and Livestock Depredation in Poland
Jedrzejewkski, W.; Nowak, S.; Jedrzejewska, B.; Myslajek, R.; Rogala, M.; Schmidt, K., World Wolf Congress 2003
In 2001-2002, a census of wolves was conducted by personnel from forestry services and national parks in Poland. The census was co-ordinated by the Mammal Research Institute of the Polish Academy of Sciences, and was based on snow tracking and annual records of wolf observations, tracks, breeding dens, and prey remains. Data were analysed using GIS (MapInfo program). The population of wolves was estimated at about 510 individuals (115 packs), which lived predominantly in eastern Poland. Mean pack size was 5.5 wolves in the Carpathian Mountains, 4 in the lowlands of NE Poland, and 2.4 in the western part of the country. The essential factors determining wolf distribution and numbers were: forest cover, forest fragmentation, human settlements, density of highways, and distance from the continuous range of wolves in Eastern Europe (east or south of Poland). Fragmentation of wolf habitats by newly planned highways and discontinuity of migration corridors are important threats to long-term survival of wolves in Poland. The most common wild prey of wolves were red deer Cervas elaphus and roe deer Capreolus capreolus. Wolf depredation on livestock (about 500 kills per year) was recorded in NE Poland (mainly cattle) and SE Poland (mainly sheep). Most cases of livestock depredation were caused by relatively few packs that settled in outskirts of large woodlands and in the mosaic habitat of small forests and pastures.
Field Immobilization of Ethiopian Wolves (Canis simensis)
Sillero-Zubiri, C., Journal of Wildlife Diseases, 32/1, January 1996, 147-151
Telazol(R) (tiletamine hydrochloride and zolazepam hydrochloride combination) and a combination of ketamine hydrochloride and acetylpromazine were used to immobilize wild Ethiopian wolves (Canis simensis) in Ethiopia from 1988 to 1992. Telazol(R) doses of 2.1 to 6.5 mg/kg resulted in a mean induction time of 2.3 + / - 0.9 min. and a mean immobilization time of 82.2 + / - 28.6 min. Induction time did not differ by dose, wolf weight, or age, but was significantly longer for females. Immobilization time differed with dose, but not by wolf weight, age, or sex. Total recovery times ranged from 50 to 158 min. There were no apparent side effects on immobilized animals. Wolves immobilized using a combination of ketamine hydrochloride and acetylpromazine had longer induction time (3.0 + / - 0.8 min.) and recovery time (114.7 + / - 29.2 min). Telazol(R) is an effective and safe agent for immobilizing Ethiopian wolves and is preferred to ketamine/acetylpromazine.
'A Fierce Green Fire': Passionate Pleas and Wolf Ecology
Jones, K., Ethics, Place & Environment, 5/1(March 200), 35 (9pp)
This paper considers the relationship between scientific rationality and emotional value in determining ideas about canine biology in North America. While science has been assumed to be objective, unassailable and devoid of value judgments, esoteric theories concerning wild predators have changed radically over time. Biologists acted as important agents in the campaign to eradicate Canis lupus from the USA during the late 1800s and early 1900s. From the 1920s onwards, scientists promulgated ecological ideas in order to redeem native carnivores. This paper suggests that, in extermination and rehabilitation phases, biologists formed their opinions of resident lupines using scientific dogma and moral precepts. By delineating the process of wolf rehabilitation in the USA, this paper situates science as a shifting body of knowledge, a way of comprehending the environment that cannot be viewed apart from cultural conceptions of biology, ethics and aesthetics.
Foraging Behaviour by Gray Wolves on Salmon Streams in Coastal British Columbia
Darimont, C ; Reimchen, T ; Paquet, P., Canadian Journal of Zoology, 81 (February 2003): 349-353 (5 pp)
Spawning salmon (Oncorhynchus spp.) are important resources for terrestrial ecosystems and often shape the ecological strategies of organisms with which they co-evolve. Gray wolves (Canis lupus), primarily predators of ungulates, are sympatric with salmon over large areas, but the relationship between the two remains poorly understood. We report here observations of direct and indirect evidence of salmon predation by wolves in several watersheds of coastal British Columbia and in detail report on the foraging behaviour of four wolves at one river during September and October 2001. Wolves oriented themselves upstream during detection and pursuit of salmon. The pooled mean capture rate was 21.5 salmon/h and mean efficiency (successes/attempt) was 39.4%. In most cases, wolves consumed only heads of salmon, perhaps for nutritional reasons or parasite avoidance. Preying on salmon may be adaptive, as this nutritious and spatially constrained resource imposes lower risks of injury compared with hunting large mammals. We infer from capture rates and efficiencies, as well as stereotypical hunting and feeding behaviour, a history of salmon predation by wolves and, as a corollary, a broad distribution of this foraging ecology where wolves and salmon still co-exist.
Forest Composition Around Wolf (Canis lupus) Dens in Eastern Algonquin Provincial Park, Ontario
Norris, D ; Theberge, Mary ; Theberge, John, Canadian Journal of Zoology, 80 (May 2002): 866-872 (7 pp)
Den-site selection is a poorly understood aspect of wolf (Canis lupus) ecology, particularly for populations in forested ecosystems. Using a geographic information system and remote-sensing imagery, we examined patterns of habitat use around wolf dens in Algonquin Provincial Park, Ontario. Sixteen den sites were sampled for eight habitat types in their immediately vicinity, as well as at radii of 500, 1000, 1500, and 2000 m. We used a resource-selection ratio to determine whether specific habitat types were preferred or avoided at different radii relative to the total proportion of habitat types found within the study area. Wolves established dens in areas with significantly high proportions of pine forest up to and including a 1000-m radius and low proportions of tolerant and intolerant hardwoods within 500 m. We conclude that wolves establish den sites based primarily on the presence of pine forest, a habitat that is frequently logged within Park boundaries and subject to problems with regeneration after cutting. Dens sites are likely not limiting in this population, but our results suggest the need to protect current den sites at a relatively large spatial scale. These results also provide unique information to assess the potential for recolonization and reintroduction of wolf populations in other areas.
From Wild Wolf to Domestic Dog: Gene Expression Changes in the Brain
Saetre, P.; Lindberg, J.; Leonard, J.A.; Olsson, K.; Pettersson, U.; Ellegren, H.; Bergstrom, T.F.; Vila, C.; Jazin, E., Molecular Brain Researchm, 126/2 (July 2004), 198 (9pp)
Despite the relatively recent divergence time between domestic dogs (Canis familiaris) and gray wolves (Canis lupus), the two species show remarkable behavioral differences. Since dogs and wolves are nearly identical at the level of DNA sequence, we hypothesize that the two species may differ in patterns of gene expression. We compare gene expression patterns in dogs, wolves and a close relative, the coyote (Canis latrans), in three parts of the brain: hypothalamus, amygdala and frontal cortex, with microarray technology. Additionally, we identify genes with region-specific expression patterns in all three species. Among the wild canids, the hypthalamus has a highly conserved expression profile. This contrasts with a marked divergence in domestic dogs....Our results suggest that strong selection on dogs for behavior during domestication may have resulted in modifications of mRNA expression patterns in a few hypothalamic genes with multiple functions. This study indicates that rapid changes in brain gene expression may not be exclusive to the development of human brains. Instead, they may provide a common mechanism for rapid adaptive changes during speciation, particularly in cases that present strong selective pressures behavioral characters.