Long-Term Effects of Timber Harvest on Ephemeral Pools and Occupancy of Spotted Salamanders (Ambystoma maculatum) and Wood Frogs (Lithobates sylvaticus)
The effects of timber harvest on amphibians can be complex and persist for years postharvest, but overall they are poorly understood. We examined how timber harvest has impacted two pool-breeding species, Spotted Salamander (Ambystoma maculatum) and Wood Frog (Lithobates sylvaticus), across the Canaan Valley National Wildlife Refuge, West Virginia, USA. We surveyed Spotted Salamanders and Wood Frogs at 49 pools from 2004 to 2016. Pools in recently harvested tracts tended to be smaller and less likely to hold water than pools in unharvested tracts for the duration of the breeding period. For both species, mean egg mass abundance was lower in harvested tracts than in the unharvested tracts, and over time declined substantially for Wood Frogs. Similarly, occupancy rates were lower in harvested sites for the duration of the study for both species. Occupancy rates declined over time for both species across all sites; this decline was steeper for Wood Frogs in harvested sites. Our results show the importance of long-term landscape-level studies when evaluating the effects of habitat disturbance. Understanding how forest loss and degradation impact pool-breeding amphibians will help to develop better management targets and mitigate compounding factors of decline to promote survival of these species.ABSTRACT

Map of CVNWR including the locations of ephemeral pools mapped and sampled for Spotted Salamanders (Ambystoma maculatum) and Wood Frogs (Lithobates sylvaticus) for a minimum of 2 yr during this study (2004–16). Shading represents forest cover. Colored areas of the map show tracts in which logging occurred at CVNWR since the 1990s. Uncolored areas have not been harvested since at least the early 1900s.

Predicted mean maximum egg mass counts as calculated using estimates from mixed-effects regression models for (A) Spotted Salamanders (Ambystoma maculatum) and (B) Wood Frogs (Lithobates sylvaticus) in ephemeral pools in unharvested and harvested forest tracts from 2004 to 2016 at CVNWR. Shaded areas correspond to confidence intervals. Egg mass count is on a logarithmic scale.

Occupancy rates for (A) Spotted Salamanders (Ambystoma maculatum) and (B) Wood Frogs (Lithobates sylvaticus) in ephemeral pools in unharvested and harvested forest tracts from 2004 to 2016 at CVNWR. Shaded areas correspond to CIs.
Contributor Notes
The work was done while serving as a visiting scientist with the U.S. Geological Survey.