TWEL Lauren Blyth Thesis

The importance of habitat heterogeneity in understanding the effect of forest management practices on salamanders

Lauren H. Blyth, MS
Advisor: Stephen Matthews 

Thesis

It is important to determine how forest management practices affect non-target species such as salamanders. Analyses commonly done at treatment or stand level suggest that salamander abundances decline after disturbance. However, salamanders have small home ranges on the scale of within-treatment habitat heterogeneity that is created by background conditions and silvicultural treatments. A finer scale within-treatment assessment of salamander responses is needed to determine how salamander species associate with the available range of habitats. Oak management regimes utilize prescribed fire, which affects forest stands unevenly due to differences in fire intensity. Salamander community data was collected from 2013-2014 in the unglaciated Appalachian plateau of Ohio three years after a series of treatments designed to mimic natural heterogeneous disturbance. The treatment consisted of thinning in 2000 followed by prescribed fires in 2001, 2005, 2010. Discriminant function analyses showed that sites did not group by treatment or replicate, and redundancy analysis showed that different salamander species associated with the range of microhabitats along a habitat gradient. Occupancy analyses were used to examine habitat relationships of the two most abundant species that represent two different life-history guilds. The common upland breeder, Plethodon cinereus (eastern red-backed salamander), associated with mesic habitats. In contrast, Ambystoma opacum (marbled salamander), a pool-breeding species, associated with increased oak composition in the overstory. Therefore, silvicultural management designed to regenerate oaks creates habitat heterogeneity that supports salamander species diversity. One species or group is not sufficient as an indicator representing all salamanders as silviculture may differentially impact species with different habitat associations. This study showed that salamander biodiversity is maintained in oak forests managed with disturbance where heterogeneity provides habitat for a range of species.