5 results on '"Jaeger, Jochen A.G."'
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2. Thresholds in the capacity of boreal caribou to cope with cumulative disturbances: Evidence from space use patterns.
- Author
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Beauchesne, David, Jaeger, Jochen A.G., and St-Laurent, Martin-Hugues
- Subjects
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WOODLAND caribou , *ECOLOGICAL disturbances , *HOME range (Animal geography) , *CUTOVER lands , *HABITATS - Abstract
Highlights: [•] We studied cumulative disturbance effect on female boreal caribou home-range size. [•] Roads and clearcuts had a significant impact on female home-range size. [•] Females expanded before contracting home-ranges as disturbance levels increased. [•] Females are seemingly constrained to suboptimal habitats at high disturbance levels. [•] Caribou seem to have limited natural capacity to cope with cumulative disturbances. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
3. Trade-off between road avoidance and attraction by roadside salt pools in moose: An agent-based model to assess measures for reducing moose-vehicle collisions
- Author
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Grosman, Paul D., Jaeger, Jochen A.G., Biron, Pascale M., Dussault, Christian, and Ouellet, Jean-Pierre
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MOOSE behavior , *SALT deposits , *SNOW & ice control on roads , *ANIMAL memory , *TRAFFIC safety & wildlife , *ECOLOGY methodology , *MULTIAGENT systems - Abstract
Moose-vehicle collisions are a frequent traffic-safety issue, particularly in northern regions where moose are attracted to the near-road areas because they can consume sodium from de-icing salts that accumulate in pools at snowmelt. Moose that find salt pools near roads tend to remember their location and to re-visit them to get the sodium they need in their diet. This study investigated the trade-off between road avoidance and salt pool spatial memory in the movement behaviour of moose using an agent-based model to determine how the interplay of these two factors influences the frequency of road crossings in the Laurentides Wildlife Reserve (Québec, Canada). Mitigation measures studied were the removal of roadside salt pools and the construction of compensatory salt pools away from the road shoulder. A GPS telemetry program of moose in the study area was used to validate our model. The model moose with both road avoidance and salt pool spatial memory activated produced the best results when comparing to the real moose data. Results show that both road avoidance and salt pool spatial memory significantly affect moose road crossings, but that road avoidance explains most of the variance. Road avoidance tended to decrease the number of moose crossings, but this decrease was partly compensated by the spatial memory of salt pools which typically increased the likelihood that moose will cross the road. The trade-off between road avoidance and salt pool memory was largest when original salt pools were maintained. In simulations where road avoidance and salt pool memory were both turned off, the impact of mitigation measures on the number of road crossings was lowest. For the most realistic moose behavior, the management scenarios resulted in reductions in road crossings between 22% and 79%, and the best scenario is to completely remove roadside salt pools. If compensation salt pools are used, they should be located as far as possible from the roads (beyond 500m) to have an impact on moose road crossings. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
4. Implementing Landscape Fragmentation as an Indicator in the Swiss Monitoring System of Sustainable Development (Monet)
- Author
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Jaeger, Jochen A.G., Bertiller, René, Schwick, Christian, Müller, Kalin, Steinmeier, Charlotte, Ewald, Klaus C., and Ghazoul, Jaboury
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FRAGMENTED landscapes , *SUSTAINABLE development , *URBAN planning , *URBAN growth - Abstract
Abstract: There is an increasing need and interest in including indicators of landscape fragmentation in monitoring systems of sustainable landscape management. Landscape fragmentation due to transportation infrastructure and urban development threatens human and environmental well-being by noise and pollution from traffic, reducing the size and viability of wildlife populations, facilitating the spread of invasive species, and impairing the scenic and recreational qualities of the landscape. This paper provides the rationale, method, and data for including landscape fragmentation in monitoring systems, using as an example the Swiss Monitoring System of Sustainable Development (Monet). We defined and compared four levels of fragmentation analysis, or fragmentation geometries (FGs), each based on different fragmenting elements, e.g., only anthropogenic, or combinations of anthropogenic and natural elements. As each FG has specific strengths and weaknesses, the most appropriate choice of FG depends on the context and objectives of a study. We present data on the current degree of landscape fragmentation for the five ecoregions and 26 cantons in Switzerland for all four FGs. Our results show that the degree of landscape fragmentation as quantified by the effective mesh size method is strongly supported by the postulates and indicator selection criteria of Monet, and we identify the most suitable FG focusing on the land area below 2100m (e.g., excluding lakes) and allowing for an equitable comparison of fragmentation degrees among regions that differ in area covered by lakes and high mountains. For a more detailed analysis of landscape fragmentation in the context of environmental impact assessments and strategic environmental assessments, a combination of all four FGs may provide a more informative tool than any single FG. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
5. Predicting when animal populations are at risk from roads: an interactive model of road avoidance behavior
- Author
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Jaeger, Jochen A.G., Bowman, Jeff, Brennan, Julie, Fahrig, Lenore, Bert, Dan, Bouchard, Julie, Charbonneau, Neil, Frank, Karin, Gruber, Bernd, and von Toschanowitz, Katharina Tluk
- Subjects
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ANIMAL populations , *MORTALITY , *TRAFFIC flow , *ANIMAL ecology - Abstract
Abstract: Roads and traffic affect animal populations detrimentally in four ways: they decrease habitat amount and quality, enhance mortality due to collisions with vehicles, prevent access to resources on the other side of the road, and subdivide animal populations into smaller and more vulnerable fractions. Roads will affect persistence of animal populations differently depending on (1) road avoidance behavior of the animals (i.e., noise avoidance, road surface avoidance, and car avoidance); (2) population sensitivity to the four road effects; (3) road size; and (4) traffic volume. We have created a model based on these population and road characteristics to study the questions: (1) what types of road avoidance behaviors make populations more vulnerable to roads?; (2) what types of roads have the greatest impact on population persistence?; and (3) how much does the impact of roads vary with the relative population sensitivity to the four road effects? Our results suggest that, in general, the most vulnerable populations are those with high noise and high road surface avoidance, and secondly, those with high noise avoidance only. Conversely, the least vulnerable populations are those with high car avoidance only, and secondly, high road surface and high car avoidance. Populations with low overall road avoidance and those with high overall road avoidance tend to respond in opposite ways when the sensitivity to the four road effects is varied. The same is true of populations with high road surface avoidance when compared to those with high car and high noise avoidance. The model further predicted that traffic volume has a larger effect than road size on the impact of roads on population persistence. One potential application of our model (to run the model on the web or to download it go to www.glel.carleton.ca/ or www.nls.ethz.ch/roadmodel/index.htm or contact the first author) is to generate predictions for more structured field studies of road avoidance behavior and its influence on persistence of wildlife populations. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
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