Underwood, H.B. 1986. Population dynamics of a central
Adirondack deer herd: Responses to intensive population and
forest management. M.S. Thesis, SUNY-ESF, Syracuse, 196 pp.
Abstract: The effects of exploitation, forest management and winter severity on the population dynamics of a central Adirondack deer herd were examined through the analysis of recent and historical data collected at the Huntington Wildlife Forest, Newcomb, New York. Key variables included in the analysis were population size, physical condition, reproduction, recruitment, growth rate and mortality. Beginning in 1966, a deer reduction program was implemented on 5,000 acres, which initiated a data collection on various aspects of deer ecology over a 19 year period, including minimal data on an unexploited, control population.
Prior to the reduction, deer densities were estimated to be between 27-35 deer/mi2. The reduction was accomplished through public hunting. both male and female deer were hunted. By 1970, the population was reduced to an estimated 2-4 deer/mi2 as a result of the hunting program in concert with 2 consecutive severe winters. the hunting program was terminated after 1970, and was resumed on the same parcel again in 1978. In the interim, intensive forest management practices changed the structure of many stands of trees, from predominantly old-growth timber to many acres of regeneration. This was hypothesized to have increased the relative capacity of the forest to sustain deer.
Deer physical condition, reproduction and recruitment increased dramatically as a result of the initial herd reduction. These characteristics were accentuated to all age classes due to the change in forest management practices with the exception of the fawn (0.5-0.7 months) age class, which showed little change throughout the 19 year period. It was determined that a female deer needs to achieve a peak fall weight of 129 pounds before ovulation is possible. This is rarely achieved in the first year of life because of the physiological limits imposed by the short growing season and harsh winters typical of the Adirondack region. In fact, the 1966 carcass collection suggested that few 2.5 year old females and fewer yearlings ovulated.
The evidence of delayed sexual maturity and unchanging physical condition despite significant improvement in range conditions suggests that the direction and magnitude of population change will be largely determined by the severity of the winter.
Further, a standing age structure skewed toward younger animals results in a less vigorous population and a pronounced time lag between bursts in population growth and winters not in the immediate past. Such age structures result from the selective removal of adult animals (males and females) in public hunting programs like those we have instituted. The combination of delayed sexual maturity in female deer and the tangle of time lag effects introduced by the selective removal of large, healthy animals have resulted in suppressed recruitment in the face of superb range conditions on the Huntington Forest.