Background information and definitions
Snags or standing dead trees and other dead wood can provide shelter for amphibians within forest. Retaining these within clearcut forest may help to maintain amphibian populations.
Studies investigating the effect of leaving coarse woody debris during harvest are discussed in ‘Leave course woody debris in forests’.
Supporting evidence from individual studies
A controlled, before-and-after study in 1994–1997 in a hardwood forest in Virginia, USA (Harpole & Haas 1999) found that retaining up to 12 wildlife and dead trees during a clear-cut did not prevent a decrease in the relative abundance of salamanders. Captures decreased significantly after treatment (before: 10; one year after: 7; three years: 1/search). Abundance did not differ within the unharvested plot (before: 10; one year after: 10; three years: 8). Treatments were on 2 ha plots. Salamanders were monitored along 2 x 15 m transects with artificial cover objects (50/plot).Study and other actions tested
A randomized, replicated, controlled, before-and-after study in 1993–1999 of four harvested hardwood forests in Virginia, USA (Knapp et al. 2003) found that leaving up to 12 wildlife or dead trees did not result in higher salamander abundances than clearcutting (see also Homyack & Haas 2009). Abundance was similar between treatments (2 vs 1/30 m2 respectively). Abundance was significantly lower than unharvested plots (6/30 m2). Species composition differed before and three years after harvest. There was no significant difference in the proportion of females carrying eggs or eggs/female for red-backed salamander Plethodon cinereus (7 eggs) or mountain dusky salamander Desmognathus ochrophaeus (12–13 eggs) in unharvested and harvested treatments (clearcut with wildlife trees/snags, shelterwood and leave-tree harvesting). The proportion of juveniles was similar except for slimy salamander Plethodon glutinosus, which had a significantly lower proportion in harvested plots. There were four sites with 2 ha plots with the following treatments: clearcutting with up to 12 wildlife or dead trees retained (small stems felled and left), clearcutting, other harvested treatments and an unharvested control. Salamanders were monitored on 9–15 transects (2 x 15 m)/plot at night in April-October. One or two years of pre-harvest and 1–4 years of post-harvest data were collected.Study and other actions tested
A randomized, replicated, controlled study in 1998–2005 of pine stands in South Carolina, USA (Owens et al. 2008) found that amphibian abundance, species richness and diversity did not differ with removal or creation of snags within forest. Abundance, species richness and diversity did not differ significantly between plots with 10-fold increase in snags (1/night; 7; 17 respectively), removal of all snags and downed course woody debris (2; 7; 18) and unmanipulated controls (2; 7; 19). Captures of anurans, salamanders and six individual species did not differ between treatments. Treatments were randomly assigned to 9 ha plots within three forest blocks. The first set of treatments was undertaken in 1996–2001 and the second set in 2002–2005. Five drift-fence arrays with pitfall traps/plot were used for sampling in 1998–2005.Study and other actions tested
In a continuation of a previous study (Knapp et al. 2003), a randomized, replicated, controlled study in 1994–2007 of six hardwood forests in Virginia, USA (Homyack & Haas 2009) found that leaving scattered wildlife or dead trees did not result in higher salamander abundance compared to clearcutting up to 13-years post-harvest. Abundance was similar between treatments (3 vs 2/transect respectively) and significantly lower than unharvested plots (7/transect). Proportions of juveniles and eggs/female were significantly lower in harvested (clearcut with wildlife trees, shelterwoods, leave-tree and group harvesting) compared to unharvested treatments for mountain dusky salamander Desmognathus ochrophaeus and juveniles for red-backed salamander Plethodon cinereus. Proportions of females carrying eggs for slimy salamander Plethodon glutinosus and southern ravine salamanders Plethodon richmondii were similar in harvested and unharvested plots. There were six sites with 2 ha plots randomly assigned to treatments: clearcutting with wildlife trees (<10 stems/ha), complete clearcutting, other harvested treatments and an unharvested control. Treatments were in 1994–1998 and salamanders were monitored at night along nine 2 x 15 m transects/site.Study and other actions tested