Postbreeding Habitat Use of the Rare, Pure-Diploid Blue-spotted Salamander (Ambystoma laterale)
The pure-diploid Blue-spotted Salamander (Ambystoma laterale) is among the rarest amphibians in northeastern North America, and data on its ecology are sparse. We assessed the movement ecology and terrestrial habitat use of A. laterale using radio- and passive integrated transponder (PIT) tag- telemetry. We radio-tracked 22 A. laterale for a median of 54 days (range 6–126 days) in the spring and summer of 2009 and 2010. Using a modified PIT tag reader, we conducted 34 in situ surveys during the spring and summer of 2009 through 2011, resulting in 42 relocations. We detected salamanders at a median straight-line distance of 67 m (range 7–281 m) from their breeding wetland. The life zone (i.e., critical terrestrial habitat), encompassing 95% of observed salamander movements, extended 152 m from the edge of the breeding wetland. Eighteen radio-tracked salamanders migrated to upland forest, three to a wet meadow, and one to a red maple (Acer rubrum) swamp. Salamanders used upland forest and wet meadow more often than the availabilities of those habitats would predict. We recorded habitat data at 10-m and 1-m-diameter circular plots centered on animal locations. At the 10-m scale, salamander presence was correlated positively with percent cover of slash and correlated negatively with percent cover of grass, total basal area of trees, and relative humidity. At the 1-m scale, salamander locations had deeper leaf litter and moister soil than did random locations. Our results suggest existing, published recommendations for the conservation of vernal pool species are applicable to A. laterale.Abstract
Major land cover types present at the study site. Letters within ellipsoids indicate cover type: HF = hayfield; RM = red maple swamp; SA = scarified area; PP = permanent pond; UF = upland forest; VP = vernal pool; WM = wet meadow. Note the southern vernal pool is the scrub–shrub pool and the northern is the open-water pool.
Pitfall trap array layout.
Sample schematic of scanning transects and locations of Blue-spotted Salamanders scanned in situ. Transects are centered on the scrub–shrub swamp vernal pool. The large circle demarcates the scanning area. Small circles represent 2009 salamander locations, and triangles and squares represent 2010 and 2011 salamander locations, respectively.
Movement paths of radio-tracked Blue-spotted Salamanders tracked in 2009 and 2010. Bold and thin lines indicate salamanders tracked in 2009 and 2010, respectively. Numbers are placed at the end of movement paths and reference the salamander ID number in Table 2.
Comparison of mean habitat variables (±95% CI) at animal locations for telemetry (triangles) and PIT tag scanning (circles) data for both 1-m and 10-m-diameter plots.
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