Genetic sampling for estimating density of common species

Area of Science:

• Wildlife ecology and population biology
• Conservation genetics and noninvasive sampling techniques
• Mammalian population estimation

Background:

• Accurate population density estimates are crucial for understanding population dynamics.
• Noninvasive genetic sampling (NGS) is cost-effective for rare or elusive species.
• The applicability of NGS to common, widely distributed species remains less explored.

Purpose of the Study:

• To evaluate the efficacy of noninvasive genetic sampling (NGS) for estimating snowshoe hare (Lepus americanus) population density.
• To compare NGS-derived population estimates with traditional live-trapping methods.
• To assess the cost-effectiveness and optimize protocols for NGS in a common species.

Main Methods:

• Optimized a single-session noninvasive genetic sampling protocol for snowshoe hares.
• Collected genetic samples (pellets) from a high density of sampling plots.
• Compared spatial capture-recapture population estimates from NGS with live-trapping data.
• Analyzed laboratory and field costs associated with NGS and live trapping.

Main Results:

• Noninvasive genetic sampling yielded population density estimates comparable to live trapping.
• NGS required a higher density of sampling plots compared to live trapping for similar precision.
• Optimal NGS protocol involved 160 sampling plots over 4 days with single pellet genotyping.
• NGS laboratory costs ranged from $670 to $3000 USD per site; field costs were lower than live trapping in difficult terrain.

Conclusions:

• Noninvasive genetic sampling is a viable method for estimating population densities of common species like snowshoe hares.
• Developing cost-effective NGS protocols requires careful field and laboratory pilot testing.
• NGS offers a potentially more cost-effective alternative to live trapping, especially in challenging environments.