Monitoring Vernal Pool Amphibians in the Northeast
In 2004, the Northeast Amphibian Research Monitoring Initiative (NE ARMI) in collaboration with National Park Service and US Fish and Wildlife Service initiated a region-wide study on the distribution of vernal pools and estimate the proportion of pools that were occupied by pool-associated amphibians (specifically, wood frogs, Lithobates sylvaticus, and spotted salamanders, Ambystoma maculatum).
At Parks and Refuges where the distribution of vernal pools was known, a random sample of known ponds was chosen for amphibian sampling. At Parks and Refuges where the distribution of vernal pools was unknown, an adaptive cluster sampling (ACS) approach was employed using a random sample from a systematic grid of points overlaid onto each park or refuge.
Partners on individual refuges and parks search for egg masses of wood frogs (Lithobates sylvaticus) and spotted salamanders (Ambystoma maculatum) by walking the perimeter of the pool multiple times each spring. To confirm that sites where egg masses were detected in spring surveys result in successful recruitment of juvenile amphibians, they revisit sites are late in the breeding season.
Since 2004, there has been a small declining trend for both species; both wood frogs and spotted salamanders occur in roughly 50% of monitored habitats on average across the region. Individual Parks and Refuges showed different dynamics across the survey period, with those in the southern part of the region more likely to show declines than those in more northern latitudes. The next step in this analysis will be to integrate information about each site (i.e., longitude, spatial position and clustering, precipitation, pool size, depth) to determine the relationship of these covariates on occupancy, annual variation, and regional and local trends.
Over the course of this project, additional surveys at individual refuges have been expanded to include exploration of the body burdens of contaminants in larval amphibians and their habitats, techniques for disease monitoring, and analysis of individual refuge variables that may be influencing declines. Currently, we are working with individual refuges using a structured decision making framework to determine the best actions to achieve individual refuge goals for vernal pool species and their habitats.
In 2004, the Northeast Amphibian Research Monitoring Initiative (NE ARMI) in collaboration with National Park Service and US Fish and Wildlife Service initiated a region-wide study on the distribution of vernal pools and estimate the proportion of pools that were occupied by pool-associated amphibians (specifically, wood frogs, Lithobates sylvaticus, and spotted salamanders, Ambystoma maculatum).
At Parks and Refuges where the distribution of vernal pools was known, a random sample of known ponds was chosen for amphibian sampling. At Parks and Refuges where the distribution of vernal pools was unknown, an adaptive cluster sampling (ACS) approach was employed using a random sample from a systematic grid of points overlaid onto each park or refuge.
Partners on individual refuges and parks search for egg masses of wood frogs (Lithobates sylvaticus) and spotted salamanders (Ambystoma maculatum) by walking the perimeter of the pool multiple times each spring. To confirm that sites where egg masses were detected in spring surveys result in successful recruitment of juvenile amphibians, they revisit sites are late in the breeding season.
Since 2004, there has been a small declining trend for both species; both wood frogs and spotted salamanders occur in roughly 50% of monitored habitats on average across the region. Individual Parks and Refuges showed different dynamics across the survey period, with those in the southern part of the region more likely to show declines than those in more northern latitudes. The next step in this analysis will be to integrate information about each site (i.e., longitude, spatial position and clustering, precipitation, pool size, depth) to determine the relationship of these covariates on occupancy, annual variation, and regional and local trends.
Over the course of this project, additional surveys at individual refuges have been expanded to include exploration of the body burdens of contaminants in larval amphibians and their habitats, techniques for disease monitoring, and analysis of individual refuge variables that may be influencing declines. Currently, we are working with individual refuges using a structured decision making framework to determine the best actions to achieve individual refuge goals for vernal pool species and their habitats.