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At least 667 records · Page 37Linked to original sources
USGS2018

Use of non-invasive genetics to generate core-area population estimates of a threatened predator in the Superior National Forest, USA

Canada lynx (Lynx canadensis) are found in boreal forests of Canada and Alaska and range southward into the contiguous United States. Much less is understood about lynx in their southern range compared to northern populations. Because lynx are currently listed as threatened under the US Endangered Species Act but have recently been recommended for delisting, information on their southern populations is important for lynx recovery, conservation, and management. We used non-invasive, genetic data collected during lynx snowtracking surveys from 2012-2017 to generate core-area estimates of abundance, trend and density in selected core areas of the Superior National Forest of Minnesota, USA. Lynx abundance estimates averaged 41.8 (SD=14.7, range=24-67) during 2012-2017 in the smaller core areas and averaged 52.3 (SD=8.3, range=43-59) during 2015-2017 in the larger core areas. We found no evidence for a decrease or increase in abundance during either period. Lynx density estimates were approximately 7-10 times lower than densities of lynx in northern populations at the low of the snowshoe hare (Lepus americanus) population cycle. To our knowledge, our results are the first attempt to estimate abundance, trend and density of lynx in Minnesota using non-invasive genetic capture-mark-recapture. Estimates such as ours provide useful benchmarks for future comparisons by providing a context with which to assess 1) potential changes in forest management that may affect lynx recovery and conservation, and 2) possible effects of climate change on the depth, density, and duration of annual snow cover and correspondingly, potential effects on snowshoe hares as well.

Minnesota↗
USGS2021

Taricha granulosa (Rough-skinned newt) predation

We found skeletal remains of fully digested Taricha granulosa in the stomach contents of 4 free-ranging, presumably healthy Strix varia (Barred Owl) collected from Roseburg, Oregon. This study recorded stomach contents from S. varia collected as part of a lethal removal experiment in localities near Cle Elum, Washington, Alsea, Oregon, and Roseburg, Oregon. In the stomach of one S. varia , we identified the remains of 14 individual T. granulosa .

Oregon, Wasington↗
USGS2003

Patterns and processes of population change in selected nearshore vertebrate predators

Sea otters and harlequin ducks have not fully recovered from the oil spill. This project will explore links between oil exposure and the lack of population recovery, with the intent of understanding constraints to recovery of these species and the nearshore environment. In FY 02, sea otter work will include aerial surveys of distribution and abundance and estimates of age-specific survival rates. Harlequin duck field studies will examine the relationship between survival and CYP1A. Captive experiments on harlequin ducks will examine the relationships between oil exposure and CYP1A induction, and metabolic and behavioral consequences of exposure.

Report↗