Underwood, H.B. 1990. Population dynamics of white-tailed deer in the central Adirondack Mountains of New York: Influences of winter, harvest and population abundance. Ph.D. Dissertation, SUNY-ESF, Syracuse, 124 pp.

Abstract: This study examined the effects of winter severity and hunter harvest on two Adirondack deer populations. Based on counts of deer along forested roadways, an index of population abundance was computed. Over the 23 year period between 1966-88, this index was capable of detecting changes in the size of a hunted and unhunted population of deer. A derived winter severity index was correlated with the rate of increase in the unhunted population. Rate of increase was zero after typical Adirondack winters, reflecting poor over-winter survival of fawns. Winters allowing large recruitment of fawns into the breeding population were relatively infrequent. The impact of hunter harvest on rate of increase was strong and lagged in time. The duration of impact correlated with the relative reproductive potential of yearling and adult females. It was speculated that changes in habitat over time have reduced the age of first reproduction by one year. However, rate of increase was not appreciably enhanced due to chronically poor recruitment of fawns. Further, repeated harvests tended to eliminate older, more vigorous females. thus, the residual population was less capable of surviving and reproducing at rates observe din unhunted populations. The conservation of age structure in the female segment of the population was identified as the critical factor to consistent production of deer in this region. Density dependent feedback to the growth rate was identified in both populations. Stochastic simulation models demonstrated that in the absence of that feedback loop, extinction was certain with two decades. However, with density feedback, the range of simulated abundance was similar to that observed in the unhunted population. Long-term abundance was linked to the between-year variation in winter severity due to the asymmetrical affect of harsh winters on rate of increase. This observation was proposed as one explanation to why deer abundance has not recovered to 1966-67 high levels. Implications for management of deer populations in northern latitudes were discussed.