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Providing evidence to improve practice

Individual study: Initial effects of clearcutting and alternative silvicultural practices on terrestrial salamander abundance

Published source details

Knapp S.M., Haas C.A., Harpole D.N. & Kirkpatrick R.L. (2003) Initial effects of clearcutting and alternative silvicultural practices on terrestrial salamander abundance. Conservation Biology, 17, 752-762


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Leave standing deadwood/snags in forests Amphibian Conservation

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.

 

Use leave-tree harvesting instead of clearcutting Amphibian Conservation

A randomized, replicated, controlled, before-and-after study in 1993–1999 of five harvested hardwood forests in Virginia, USA (Knapp et al. 2003) found that leave-tree harvesting did not result in higher salamander abundances than clearcutting (see also Homyack & Haas 2009). Abundance was similar in the leave-tree and clearcut plots (2 vs 1/30 m2 respectively). Abundance was significantly lower than unharvested plots (6/30 m2). Species composition differed before and three years post-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 (leave-tree, shelterwoods and clearcut with wildlife trees or snags left). The proportion of juveniles was similar except for slimy salamander Plethodon glutinosus, which had a significantly lower proportion in harvested plots. There were five sites with 2 ha plots with the following treatments: leave-tree harvest (up to 50 trees/ha retained uniformly; average 28%), 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.

 

Harvest groups of trees instead of clearcutting Amphibian Conservation

A randomized, replicated, controlled, before-and-after study in 1993–1999 of five harvested hardwood forests in Virginia, USA (Knapp et al. 2003) found that harvesting trees in groups did not result in higher salamander abundances than clearcutting. Abundance was similar between treatments (groups: 3; clearcut: 1/30 m2 respectively; see also Homyack & Haas 2009). Abundance was significantly lower compared to unharvested plots (6/30 m2). Species composition differed before and three years after harvest. There were five sites with 2 ha plots with each treatment: group harvesting (2–3 small area group harvests with selective harvesting between), clearcutting 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.

 

Use shelterwood harvesting instead of clearcutting Amphibian Conservation

A randomized, replicated, controlled, before-and-after study in 1993–1999 of five harvested hardwood forests in Virginia, USA (Knapp et al. 2003) found that shelterwood harvesting resulted in significantly higher salamander abundances than clearcutting (3 vs 1/30 m2; see also Homyack & Haas 2009). However, 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 (shelterwoods, leave-tree and clearcut with wildlife trees or snags left). The proportion of juveniles was similar except for slimy salamander Plethodon glutinosus, which had a significantly lower proportion in harvested plots. There were five sites with 2 ha plots with the following treatments: shelterwoods (41–81% removed), 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.

 

Use herbicides to control mid-storey or ground vegetation Amphibian Conservation

A randomized, replicated, controlled in 1993–1999 of four harvested forests in Virginia, USA (Knapp et al. 2003) found that salamander abundance was similar in plots with and without herbicide treatment (7 vs 6/30 m2; see also (Homyack & Haas 2009). Four sites had 2 ha plots with herbicide application (Garlon4) to reduce woody shrubs and a control with no management. Salamanders were monitored on 9–15 transects (2 x 15 m)/plot at night in April–October. Monitoring was undertaken 1–2 years before and 1–4 years after treatment.