Amphibian and reptile community response to coarse woody debris manipulations in upland loblolly pine (Pinus taeda) forests

Add woody debris to landscapes

A replicated, randomized, controlled study in 2002–2005 of pine stands in South Carolina, USA (Owens et al. 2008, same experimental set-up as Davis et al. 2010) found that adding coarse woody debris (downed or standing) did not increase reptile abundance, species richness or diversity compared to areas with no debris added. Plots with added woody debris (downed and standing) were similar to unmanipulated plots in terms of reptile abundance (debris added: 0.3–0.5 individuals/plot vs unmanipulated: 0.4), richness (5–7 species vs. 7) and diversity (10–17 vs. x 13, Shannon-Weiner diversity index). Reptile richness was higher in plots with added downed debris (7 species) compared to plots with added standing debris (5 species). In 2002–2005, nine ha plots within three forest blocks had either downed woody debris added (3 plots, increased five-fold); standing woody debris added (3 plots, increased 10-fold) or were left unmanaged (3 plots). In 2002–2005, fourteen days of sampling were carried out each season (except in spring 2004, when there were 28 days) using drift fences with pit-fall traps.

(Summarised by: Katie Sainsbury)

Leave standing/deadwood snags in forests

A replicated, randomized, controlled study in 1998–2005 of pine stands in South Carolina, USA (Owens et al. 2008, same experimental set-up as Davis et al. 2010) found that the creation or removal of snags (standing dead trees) had no effect on reptile abundance, species richness and diversity compared to not manipulating debris in forests. In two trials, reptile abundance, species richness and diversity was similar between plots with snags added (abundance: 0.2–0.3 individuals/plot, richness: 5–6 species, diversity: 10–13 Shannon-Weiner index), or all snags and coarse woody debris removed (0.3–0.5, 6–7, 13–17), compared to not manipulating debris (0.3–0.4, 7, 13–17). In the second trial, reptile abundance, richness and diversity were lower when standing snags were added (0.3 individuals/plot, 5 species, 10 Shannon-Weiner index, respectively) compared to when all woody debris was removed (0.5, 7, 17). Snake abundance was higher with woody debris removal compared to snag addition (debris removal: 0.2 individuals/plot; snags added: 0.1), but lizard abundance was not (debris removal: 0.3 individuals/plot; snags added: 0.2). Treatments were randomly assigned to 9 ha plots within three forest blocks in 1996–2001: standing snag addition (10 fold increase), all woody debris removal, downed woody debris addition (five-fold increase), and no manipulation and in 2002–2005: downed woody debris addition, woody debris removal, standing snag addition, and no manipulation. Reptiles were sampled using drift fences with pitfall traps in 1998–2005.

(Summarised by: Katie Sainsbury)

Leave coarse woody debris in forests

A randomized, replicated, controlled study in 1998–2005 of pine stands in South Carolina, USA (Owens et al. 2008) found that the removal of coarse woody debris did not effect amphibian abundance, species richness or diversity. Plots with all downed and standing woody debris removed did not differ significantly from controls in terms of abundance (1–2 vs 2), species richness (7 vs 7) or diversity (17–18 vs 19). The southern leopard frog Rana sphenocephala had greater capture rates with removal rather than addition of woody debris (0.11 vs 0.02/night). Treatments were randomly assigned to 9 ha plots within three forest blocks. The first set of treatments was undertaken in 1996–2001 and a second set in 2002–2005. Control plots had no manipulation of woody debris. Five drift-fence arrays with pitfall traps/plot were used for sampling in 1998–2005.

(Summarised by: Rebecca K Smith)

Leave standing deadwood/snags in forests

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.

Create refuges

A randomized, replicated, controlled study in 1998–2005 of pine stands in South Carolina, USA (Owens et al. 2008) found that adding coarse woody debris to forest did not effect amphibian abundance, species richness or diversity. Plots with added downed woody debris did not differ significantly from controls in terms of amphibian abundance (1–2 vs 2), species richness (6–7 vs 7) or diversity (17 vs 19). One species, the southern leopard frog Rana sphenocephala, had lower capture rates with the addition compared to removal of woody debris (0.02 vs 0.11/night). Treatments were randomly assigned to 9 ha plots within three forest blocks. The first set of treatments was undertaken in 1996–2001 and a second set in 2002–2005. Woody debris was increased five-fold. Control plots had no manipulation of woody debris. Five drift-fence arrays with pitfall traps/plot were used for sampling in 1998–2005.

Leave woody debris in forests after logging

A replicated, randomized, controlled study in 1998–2005 of pine stands in South Carolina, USA (Owens et al. 2008, same experimental set-up as Davis et al. 2010) found that leaving coarse woody debris in place had no effect on reptile abundance, species richness and diversity compared to removing it. In two trials, removing all downed and standing woody debris did not change reptile richness (debris removed: 5–7 species), diversity (10–17, Shannon-Weiner index) and abundance (0.2–0.5 individuals/plot/night) compared to not manipulating woody debris (richness: 7, diversity: 13–17, abundance: 0.3–0.4). The two treatments were randomly assigned to 9 ha plots within three forest blocks in 1996–2001 and 2002–2005: all woody debris removal or no manipulation. Five drift-fence arrays with pitfall traps/plot were used for sampling in 1998–2005.

(Summarised by: Katie Sainsbury)