Monday, October 25, 2010
Compensatory Rebound Effect (CRE) is why killing does not work .
What is Compensatory Rebound Effect?
"Reproductive rebound is a well documented population dynamic in deer and other mammals. Deer conceive multiple embryos but the number of fawns actually born is determined by a number of complex factors including nutrition and herd density. With competition for food reduced by a sudden drop in herd numbers, younger fawns will breed and females will give birth to twins and triplets instead of single fawns.In its 1990 report, "An Assessment of Deer Hunting in New Jersey," New Jersey Fish and Game offered a detailed example of this process. Its report shows that even during hunting seasons in which killing female deer was the objective (antlerless seasons), the remaining females had increased birthrates that not only replaced the ones killed, but increased the overall size of the herd. "http://www.pzpinfo.org/pzp_faqs.html
"The researchers note that in each instance, disease outbreaks have worsened in response to the hunting.One reason the policies failed, Choisy and Rohani said, is that they didn’t take into account an ecological principle known as compensation. When a portion of the animal population is reduced, those that survive are left with more resources such as food and shelter. As a result of the newly plentiful resources, the death rate decreases and the birth rate increases, compensating – and sometimes overcompensating – for the loss."
Hunting Can Increase The Severity Of Wildlife Disease Epidemics
http://www.google.com/images?oe=UTF-8&gfns=1&q=food+plot+and+hunting&um=1&ie=UTF-8&source=og&sa=N&hl=en&tab=wi&biw=1551&bih=816, to really "boost" the deer population. They are so preoccupied with fawn birth to create larger deer herd size and their main interest in the buck fawns.
“By keeping the deer population below the carrying capacity of the available habitat, more forage (nutrition) is available per deer. Thus, does are healthier, reproductive success is higher and more does are able to carry two fawns. Ironically, this can result in a greater deer harvest each year. Depending on the relationship of the population and the carrying capacity, an „optimum sustained yield‟ can be achieved where a relatively high reproductive rate allows an abundant harvest each fall. With high-quality habitat and increased nutrition, the percentage ofdoe fawns that breed their first fall increases (sometimes up to 25 percent). Also, a higher percentage of yearling does produce two fawns instead of one. Because fawns are born at approximately a 1:1 sex ratio, more bucks may be born each year. Therefore, in some areas, you actually can increase the number of bucks born by shooting more does.”“Quality Deer Management: Guidelines for Implementation,” 6. Agricultural Extension Service, The University of Tennessee. http://www.utextension.utk.edu/publications/p... (last accessed November 2008)
ANATOMY OF A "DOE" HUNT:
How Killing Female Deer at the Watchung Reservation Increased Birth Rates and Reproduction