Journal of Wildlife Management 1: Bears, Bears and Bears, Oh My!

Hey all,

Thought I could finally put some of these journal articles to good use, mostly they just collect dust in my apartment. Most of them are aimed at wildlife population ecology, the role of wildlfe management/conservation and human-wildlife interactions. My attempt for doing this is to provide more examples of population ecology studies as well as showing the human incorporation into wild populations through management and he reasons behind such management. I will be summarizing the main points of these articles and how they apply to the class.

Enjoy if anyone cares to look (doubtful)…

Management and Conservation Article:

DNA-Based Population Demographics of Black Bears in Coastal North Carolina and Virginia.
Tredick, C.A. and Vaughan, M.R.
Journal of Wildlife Management, September 2009

Noninvasive genetic sampling has become a popular method for obtaining population parameter estimates for black (Ursus americanus) and brown (U arctos) bears. These estimates allow wildlife managers to develop appropriate management strategies for populations of concern. Black bear populations at Great Dismal Swamp (GDSNWR), Pocosin Lakes (PLNWR), and Alligator River (ARNWR) National Wildlife Refuges in coastal Virginia and North Carolina, USA, were perceived by refuge biologists to be at or above cultural and perhaps biological carrying capacity, but managers had no reliable abundance estimates upon which to base population management. We derived density estimates from 3,150 hair samples collected noninvasively at each of the 3 refuges, using 6-7 microsatellite markers to obtain multilocus genotypes for individual bears. We used Program MARK to calculate population estimates from capture histories at each refuge. We estimated densities using both traditional buffer strip methods and Program DENSITY. Estimated densities were some of the highest reported in the literature and ranged from 0.46 bears/km2 at GDSNWR to 1.30 bears/km2 at PLNWR. Sex ratios were male-biased at all refuges. Our estimates can be directly utilized by biologists to develop effective strategies for managing and maintaining bears at these refuges, and noninvasive methods may also be effective for monitoring bear populations over the long term.

The purpose of the study was to identify black bear demographics in three National Wildlife Refuges in in this small region of the U.S. Black bear populations in this region seem to be higher than cultural carrying capacities for the area as perhaps above the biological carrying capacity. These demographic and population results were needed by both state and federal government wildlife managers in order to attempt to manage these populations at levels were the biological interity was upheld wihle at the same time minimizing negative human-bear interactions in the area associated with increasing population sizes.

Methods for data collection for the population included noninvasive collection of tissue samples through hair-trapping and scat capture (thought this would make it sounds more intreging). These noninvasive techniques are more cost effective than invasive techniques such as animal capture-mark-recapture methods, and put less stress on the animals. The samples provided were used to determine population size, density, and sex ratios from DNA obtained from the samples. More specifically, they used this data to input into population models and found estimations for population size, density and sex ratios.

They found there density estimates to be some of the highest in literature records, however hey also correspond to other estimates in of areas of the region. The article does not specify if these estimates are below, at or above cultrual or biological carrying capacities, but one could assume that they are most likely above the cultural carrying capacity and perhaps approaching the biological capacity.

This article relates to the lectures over population ecology and carrying capacities specifically. It is important to determine the differences between biological carrying capacity and cultural (or socially acceptable) carrying capacities. The role of wildlife managers is often to find a balance between the biological, "natural," carrying capacities for wildlife populations and the abundance of these species that is socially acceptable, even if what is socially acceptable is not always best for the ecosystem. This balance often involves tough decisions and arguments depending on the constituants involved and eludes to the complexity of natural resource management coupled with human social systems.

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