This paper illustrates how age‐at‐harvest data, when combined with hunter‐effort information routinely collected by state game management agencies, can be used to estimate and monitor trends in big game abundance. Twenty‐four years of age‐at‐harvest data for black‐tailed deer (Odocoileus hemionus) were analyzed to produce abundance estimates ranging from 1,281 adult females to 3,232 adult females on a 22,079‐ha tree farm in Pierce County, Washington, USA. The annual natural survival probability was estimated to be 0.7293 ( = 0.0097) for this female population. The estimated abundance was highly correlated with an independent browse damage index (r = 0.8131, P < 0.001). A population reconstruction incorporating the browse index did not substantially improve the model fit but did provide an auxiliary model for predicting deer abundance. This population reconstruction illustrates a cost‐effective alternative to expensive big game survey methods.
We used cohort analysis to reconstruct a Columbian black‐tailed deer (Odocoileus hemionus columbianus) population from 1979 to 1999 in the western Cascade Range, Washington, USA. We used reconstructed population estimates and age‐class representations to analyze relationships among fawn recruitment, deer density, forage availability, and weather influences during the fawning period. Fawn recruitment was found to be significantly correlated with deer density the previous year as well as available forage in the previous year. Weather variables that described cold temperatures early in the fawning period and high precipitation levels during the prime fawning period were found to negatively affect fawn recruitment. Models could be used to assist with management of black‐tailed deer by providing an estimate of cohort strength when productivity survey methods prove difficult.
We used cohort analysis to reconstruct the female segment of a Columbian black‐tailed deer (Odocoileus hemionus columbianus) population from 1979 to 2000 in the western Cascades of Washington, USA. We used reconstructed population estimates and age class representations to analyze relationships between population change and female density, forage availability, and weather influences. We applied stage structured and unstructured modeling approaches and used information‐theoretic methods to select the best models. We used habitat covariates to develop predictive functions for fertility and survival parameters in structured models. The best structured and unstructured models were composed of combinations of factors including population density, forage availability, and winter weather. Structured and unstructured models could assist with management of black‐tailed deer by providing the ability to predict deer population change given covariate values.
Stands identified as potential Canadian lynx denning habitat by a habitat suitability model were sampled in northeastern Washington for stand structure and understory structural features identified as important for denning lynx. Potential den structures were quantified by use of strip transects, and stand structure was quantified through an enhanced forest inventory approach focused on assessing understory and downed wood conditions. Information theoretic model selection methods indicated that the best model to predict potential denning understory structure availability included downed wood abundance, total basal area, and average stand diameter. The strong predictive ability of our models suggest that understory features important to denning lynx can be predicted using traditional inventory data with the addition of a downed wood line intercept methodology. In general, our study supports the suggestion that assessing downed wood availability will effectively address concerns over quantifying the availability of understory structural features identified as being important at lynx den sites. West. J. Appl. For. 20(4):224–227.
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