Factors affecting the growth of a moss species necessary for nesting habitat restoration of the four-toed salamander (Hemidactylium scutatum, Temminck and Schlegel 1838)

Abstract

Habitat loss and degradation is threatening amphibian populations worldwide. The four-toed salamander, Hemidactylium scutatum, is a small plethodontid salamander that deposits eggs terrestrially in moss clumps overhanging vernal pools. Hemidactylium scutatum has declined across its range, largely due to the loss of wetland habitat necessary for breeding. Constructed ponds and wetlands are common tools used to combat amphibian declines, but they often require several years for natural vegetation communities to establish. As a result, there have been calls to better understand the factors that promote the growth of critical habitat components to refine ex situ cultivation methods and expedite restoration effort. Here we evaluate the factors that influence the growth of Climacium americanum moss, a preferred nesting substrate of H. scutatum, in a greenhouse setting. We examined the impacts of plant density, soil type, and soil moisture on changes in biomass. Our analysis determined that density has little impact on growth rates while two of the three soil types had a significantly higher change in mass. We determined soil moisture-as a result of soil type–is the most critical component in greenhouse-grown moss, with plants in the 75th quartile of moisture seeing the largest positive change in biomass. Our results show that growing moss in greenhouses for use in constructed wetlands is achievable when proper soil moisture is maintained. Ultimately, this work aids restoration efforts for H. scutatum by providing a simple methodology to produce high volumes of nesting habitat and promote population recovery.