9 research outputs found

    Restoration of Woodland Caribou to the Lake Superior Region

    Get PDF
    Woodland caribou (Rangifer tarandus caribou) historically occupied the boreal forest zone across the North American continent. The distribution and abundance of the species has declined in the past century. In particular, it has been extirpated from much of the southern limits of its historical range on both sides of the boundary between Canada and the United States (Bergerud 1974). Translocation of animals from extant populations may be used to reestablish populations in portions of the species\u27 former range. Recently, wildlife biologists in Ontario have translocated woodland caribou to a number of sites in or adjacent to Lake Superior. While it is too soon to evaluate their long-term success, these restoration efforts do provide useful insights into factors likely to influence the outcome of woodland caribou translocations elsewhere. In this chapter, we examine the 1) historical changes in range distribution, 2) natural history characteristics and requirements, and 3) results of recent translocations of woodland caribou, and use them to evaluate several alternative sites for possible woodland caribou restoration in the Lake Superior region. We also apply minimum viable population analysis to evaluate several translocation scenarios

    Wolf Population Dynamics

    Get PDF
    A LARGE, DARK WOLF poked his nose out of the pines in Yellowstone National Park as he thrust a broad foot deep into the snow and plowed ahead. Soon a second animal appeared, then another, and a fourth. A few minutes later, a pack of thirteen lanky wolves had filed out of the pines and onto the open hillside. Wolf packs are the main social units of a wolf population. As numbers of wolves in packs change, so too, then, does the wolf population (Rausch 1967). Trying to understand the factors and mechanisms that affect these changes is what the field of wolf population dynamics is all about. In this chapter, we will explore this topic using two main approaches: (1) meta-analysis using data from studies from many areas and periods, and (2) case histories of key long-term studies. The combination presents a good picture-a picture, however, that is still incomplete. We also caution that the data sets summarized in the analyses represent snapshots of wolf population dynamics under widely varying conditions and population trends, and that the figures used are usually composites or averages. Nevertheless, they should allow generalizations that provide important insight into wolf population dynamics

    Wolf Population Dynamics

    Get PDF
    A LARGE, DARK WOLF poked his nose out of the pines in Yellowstone National Park as he thrust a broad foot deep into the snow and plowed ahead. Soon a second animal appeared, then another, and a fourth. A few minutes later, a pack of thirteen lanky wolves had filed out of the pines and onto the open hillside. Wolf packs are the main social units of a wolf population. As numbers of wolves in packs change, so too, then, does the wolf population (Rausch 1967). Trying to understand the factors and mechanisms that affect these changes is what the field of wolf population dynamics is all about. In this chapter, we will explore this topic using two main approaches: (1) meta-analysis using data from studies from many areas and periods, and (2) case histories of key long-term studies. The combination presents a good picture-a picture, however, that is still incomplete. We also caution that the data sets summarized in the analyses represent snapshots of wolf population dynamics under widely varying conditions and population trends, and that the figures used are usually composites or averages. Nevertheless, they should allow generalizations that provide important insight into wolf population dynamics

    The role of demographic compensation theory in incidental take assessments for endangered species

    Get PDF
    Many endangered species laws provide exceptions to legislated prohibitions through incidental take provisions as long as take is the result of unintended consequences of an otherwise legal activity. These allowances presumably invoke the theory of demographic compensation, commonly applied to harvested species, by allowing limited harm as long as the probability of the species’ survival or recovery is not reduced appreciably. Demographic compensation requires some density-dependent limits on survival or reproduction in a species’ annual cycle that can be alleviated through incidental take. Using a population model for piping plovers in the Great Plains, we found that when the population is in rapid decline or when there is no density dependence, the probability of quasi-extinction increased linearly with increasing take. However, when the population is near stability and subject to density-dependent survival, there was no relationship between quasi-extinction probability and take rates. We note however, that a brief examination of piping plover demography and annual cycles suggests little room for compensatory capacity. We argue that a population’s capacity for demographic compensation of incidental take should be evaluated when considering incidental allowances because compensation is the only mechanism whereby a population can absorb the negative effects of take without incurring a reduction in the probability of survival in the wild. With many endangered species there is probably little known about density dependence and compensatory capacity. Under these circumstances, using multiple system models (with and without compensation) to predict the population’s response to incidental take and implementing follow- up monitoring to assess species response may be valuable in increasing knowledge and improving future decision making

    Supplement 1. Matlab model code and data.

    No full text
    <h2>File List</h2><div> <p><a href="GELAM.m">GELAM.m</a> (MD5: 0b7829a3095eef051873e580609de32b)</p> <p><a href="Location2West.txt">Location2West.txt</a> (MD5: 4ddcd8b65a095ace631d05ca597d125c)</p> </div><h2>Description</h2><div> <p>The MATLAB (version R2010a, MathWorks) script GELAM.m runs a simulation model to estimate acute mortality of golden eagles due to ingesting lead from gut-piles of harvested big game animals and to assess possible mitigation strategies: non-lead ammunition and gut-pile retrieval. GELAM.m runs the simulation both at the state level, and for the Casper example.</p> <p>Location2West.txt contains the data we used in the MATLAB simulations, with the following columns: (1) ID number (FID), (2) number of animals harvested, (3) golden eagle abundance in hunting unit, and (4) size of hunting unit in 100 km² blocks. Information was compiled from publicly available data for Wyoming’s 2012 big game harvest (Wyoming Game and Fish Department 2013, <i>public communication: 2012 annual report of big and trophy game harvest. http://wgfd.wyo.gov/web2011/Departments/Wildlife/pdfs/HR2012_FULLREPORT0005408.pdf accessed 13 May 2014</i>) and preliminary, unpublished estimates of late summer Golden Eagle abundance provided by Ryan Nielson (<i>personal communication</i>, <i>Western EcoSystems Technology, Inc., Cheyenne, WY, February 2014</i>).</p> <p>The eagle density data are from ongoing work that may be revised, using methods reported in two publications: </p> <p>Nielson, R. M. and H. Sawyer. 2013. Estimating resource selection with count data. Ecology and Evolution 3:2233–2240.</p> <p>Neilson, R., L. McManus, T. Rintz, L. L. McDonald, R. K. Murphy, W. H. Howe, and R. E. Good. 2014. Monitoring abundance of golden eagles in the Western United States. Journal of Wildlife Management 78:721–730.</p> </div
    corecore