SREL Reprint #1810





Estimating population density of moles Scalopus aquaticus using assessment lines

Gregory D. Hartman and John D. Krenz

Density was estimated for three populations of eastern moles Scalopus aquaticus Linnaeus, 1758, in South Carolina using a trapping grid and assessment lines. Assessment line data were based upon the repair of holes punched into surface tunnels of the animals. Using a new method of analysis for assessment line data, a logistic curve was fitted to the data. Density estimates based upon these analyses were (95% confidence intervals in parentheses) 3.02 (1.90 - 4.98), 2.73 (1.48 - 12.52), and 1.71 (0.86 - 2.69) moles/ha. In previous studies using assessment line data to estimate density, obtaining confidence intervals for the density estimate presented theoretical problems. In this study, Monte Carlo procedures were used to obtain an estimate of the approximate 95% confidence intervals for density. The analytical methods used in the present study eliminate the concepts of boundary strip width (strict sense) and the occurrence of distinctive zones with constant capture probabilities, and as such, represent important conceptual improvements of the assessment line density estimation method.

Key words: Scalopus aquaticus, Talpidae, assessment lines, population density, South Carolina

SREL Reprint #1810

Hartman, G.D. and J.D. Krenz. 1993. Estimating population density of moles Scalopus aquaticus using assessment lines. Acta Theriologica 38:305-314.

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