Translator Disclaimer
1 December 2004 An assessment of indices of relative and absolute abundance for monitoring populations of small mammals
Author Affiliations +
Abstract

Knowledge of small-mammal population densities and species richness values are crucial to wildlife conservation and many ecological investigations. The relationship between estimates of absolute abundance and relative abundances of small-mammal populations is unclear. Therefore, from 1999–2001 measures of relative and absolute abundance of small mammals were compared across a terrestrial landscape using 3 vegetation communities (forest, early-successional field, and forest-field edge) in western Tennessee. We used a catch/unit effort index derived from transect sampling to estimate relative abundance and 2 estimates of absolute abundance, Mt 1 (the number of unique individuals captured) and Nest (a population estimate obtained from statistical models). These 2 estimates were derived from mark-recapture sampling on trapping grids. Using both sampling procedures, we conducted trapping with Sherman live traps during autumn, winter, and spring for 2 years. We tested the prediction that the pattern of total captures of small mammals across a landscape from a catch/unit effort index reflects the same pattern as those derived from Mt 1 and Nest. Also, we tested the prediction that the pattern of species richness of small mammals derived from a catch/unit effort index on transects corresponds with the species richness based on Mt 1 determined from grid sampling. We conducted comparisons of patterns using a Spearman rank correlation coefficient. Overall, we captured 988 small mammals, representing 9 genera and 11 species. The pattern of captures from the catch/unit effort index was proportional to those derived from Mt 1 and Nest. (P ≤ 0.001 in each correlation analysis; rs17 = 0.880 and rs17 = 0.810, respectively). The pattern of species richness derived from the catch/unit effort index was similar to those derived from the mark-recapture sampling (P ≤ 0.001; rs17 = 0.861). Capture frequencies across vegetation communities and within seasons from both transect sampling and grid sampling did not differ for 4 of 6 seasons (χ22 = 4.4329, P = 0.1090; χ22 = 18.2224, P = 0.0001; χ22 = 0.2129, P = 0.8990; χ22 = 1.6395, P = 0.4405; χ22 = 3.8688, P = 0.1445; χ22 = 7.1750, P = 0.0277). Results of this study suggest that measures of relative abundance provide patterns of population trends proportional to those derived from estimates of absolute abundance.

Heidi L. Hopkins and Michael L. Kennedy "An assessment of indices of relative and absolute abundance for monitoring populations of small mammals," Wildlife Society Bulletin 32(4), (1 December 2004). https://doi.org/10.2193/0091-7648(2004)032[1289:AAOIOR]2.0.CO;2
Published: 1 December 2004
JOURNAL ARTICLE
8 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top