Showing papers by "John D. C. Linnell published in 2006"

Diet of Eurasian lynx, Lynx lynx, in the boreal forest of southeastern Norway: the relative importance of livestock and hares at low roe deer density

Abstract: The year-round food habits of lynx were studied using radio-telemetry and snow-tracking in the boreal forest of southeastern Norway. The main objectives of the study were to clarify the importance of domestic sheep and small prey species in the diet of lynx in an area with a very low density of roe deer. During the period 1995–1999, we found 193 scats and 358 kills made by lynx. Our results indicate that roe deer were the most common prey species (contributing to 83 and 34% of the biomass consumed in winter and summer, respectively), although a wide range of other species were also found, including mountain hares, tetranoids, red foxes, domestic sheep, wild reindeer, and even moose. Most of the diet was obtained by predation, although we did document several cases of scavenging. Roe deer were more important in the diet in winter than in summer, perhaps because they were easier to locate in winter as they clustered around feeding sites. In summer, domestic sheep and small prey increased in importance. Despite the very low density of roe deer in this study area, lynx seemed to still specialise on them, although domestic sheep did constitute a significant amount to their diet, especially for males and yearlings. However, the contribution of sheep to summer diet was far from that expected if their relative density was considered.

Risk taking by Eurasian lynx (Lynx lynx) in a human‐dominated landscape: effects of sex and reproductive status

Abstract: This study aimed to test how the sex and reproductive status of Eurasian lynx influenced their use of ‘attractive sinks’ – habitats with high prey density and high mortality risks. Locations of 24 Eurasian lynx Lynx lynx were obtained by radiotelemetry in a mixed forest and agricultural habitat in south-eastern Norway. Roe deer, the major food source of lynx in the study area, occurred at higher densities closer to areas of human activity and infrastructure. Proximity of lynx locations to human activity and infrastructure was used as a risk index because the most common causes of death among Scandinavian lynx were of anthropogenic origin. This study shows that distances from lynx locations to human activity were significantly greater for females with newborn kittens than for males, but this decreased with kitten age. The data suggest that this response to human activity is influenced by the reproductive strategies of males and females, and might explain male-biased human-induced mortality in this study and in carnivores more generally.

Impact of infrastructure on habitat selection of wolverines Gulo gulo

Abstract: Compared to the other northern large carnivores, wolverines Gulo gulo are thought to be the most sensitive species with regard to habitat changes and human disturbance. Nowadays wolverines in Scandinavia are found in remote high alpine areas, and we investigated whether human development through presence of infrastructure has relegated them to these areas. We analysed wolverine habitat selection and the impact of infrastructure in two study areas in Norway using compositional analysis. We found that alpine tundra with low human development was important for wolverines to locate their home ranges. Human development formed a more important factor for home range location than did habitat, because habitat selectivity was much higher in undeveloped habitats than in developed habitats. Within their home ranges, wolverines used alpine shrubland and forest, irrespective of human development. The sympatric distribution of wolverines with wild and semi-domestic reindeer Rangifer tarandus indicates that wol...

Population structure in a critically endangered arctic fox population: does genetics matter?

Abstract: The arctic fox (Alopex lagopus) in Scandinavia is classified as critically endangered after having gone through a severe decline in population size in the beginning of the 20th century, from which ...

Does the spatiotemporal distribution of livestock influence forage patch selection in Eurasian lynx Lynx lynx

Abstract: Depredation on livestock is one of the main conflicts associated with Eurasian lynx Lynx lynx conservation in Norway. Our study investigates how Eurasian lynx utilise high-density patches of free-ranging and unguarded livestock (domestic sheep Ovis aries and semi-domestic reindeer Rangifer tarandus) as compared to patches associated with low-density wild ungulate prey, roe deer Capreolus capreolus. We monitored 10 radio-collared lynx in central Norway in two seasons that differed in ungulate distribution and density. According to the 'optimal foraging theory' an animal should preferentially utilise areas with more abundant food if not constrained by other factors; therefore we predicted that lynx should select patches containing livestock. Contrary to our prediction the results indicate no selection for livestock patches in any season. In contrast, a clear preference was shown for roe deer patches in both seasons. Our findings support the hypothesis that lynx depredation on livestock seems to be ...

The future role of large carnivores in terrestrial trophic interactions: the northern temperate view

Abstract: … I have lived to see state after state extirpate its wolves. I have watched the face of many new wolfless mountains, and seen the south‐facing slopes wrinkle with a maze of new deer trails. I have seen every edible bush and seedling browsed, first to anemic desuetude, and then to death … I now suspect that just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer . Aldo Leopold 1949. INTRODUCTION Central to any treatment of factors affecting the ecological role of large herbivores is a discussion about the factors influencing large herbivore population size and dynamics, and whether they are most influenced by top‐down, or bottom‐up, processes (Pace et al . 1999). The role of resource limitation (a bottom‐up process) in herbivore dynamics is well‐documented from many studies throughout the temperate zone (e.g. Fowler 1987, Gaillard et al . 2000). In contrast, the extent to which predation (a top‐down process) influences herbivore dynamics is less clear, at least in part due to the fact that many of the most detailed long‐term studies of herbivore population dynamics have been conducted in predator‐free environments. The conceptual elegance of strong top‐down effects on herbivores is clear in prosaic statements like Leopold's in the opening quotation, although the absence, or redundancy, of this effect has lain behind the philosophical adoption of the ‘natural regulation’ doctrine in US national parks.

Intra-specific variation and taxa- sampling affects the home range — body mass relationship

Abstract: The relationship between home range size and body mass is a frequently studied allometric relationship. However, the results of various studies differ greatly, leading to much debate about the nature of the relationship. We argue that this confusion is not surprising, due to intra-specific variation in home range size caused by ecological variability rather than by body mass. By random resampling of different studies from within 16 Carnivora species, we show that the scaling exponent ranged from 0.30–1.54 depending on the particular studies included for each species. Of these exponents, 10% did not contain 0.75 within their confidence limits, and 5.5% did not contain 1.00. Furthermore, by randomly sub-sampling 16 species from a total sample of 58 species, we found that the scaling exponent varied between 0.18 and 2.76. Of these exponents, 42.2% did not contain 0.75 within their confidence limits, whereas 16.8% did not contain 1.00. Therefore, we strongly recommend that greater consideration be paid to intra-specific ecological variability and taxa selection when dealing with both allometry and cross-species life history studies.

Gauperegistrering i utvalgte fylker 2006

Abstract: ...................................................................................................................................... 4 Innhold ......................................................................................................................................... 5 Forord .......................................................................................................................................... 6 1 Innledning ............................................................................................................................... 7 2 Materiale og metoder ............................................................................................................ 7 3 Resultater ............................................................................................................................... 8 3.1 Gjennomføring ................................................................................................................. 8 3.2 Gaupeindeksen ................................................................................................................ 8 3.2.1 Nordland.............................................................................................................. 15 3.2.2 Nord-Trøndelag ................................................................................................... 15 3.2.3 Hedmark.............................................................................................................. 15 3.2.4 Oslo og Akershus................................................................................................ 15 3.2.5 Buskerud ............................................................................................................. 21 3.2.6 Telemark ............................................................................................................. 21 4 Diskusjon .............................................................................................................................. 23 5 Referanser ............................................................................................................................ 24