Effects of timber harvest on amphibian populations: understanding mechanisms from forest experiments

Published source details Semlitsch R.D., Todd B.D., Blomquist S.M., Calhoun A.J.K., Whitfield-Gibbons J., Gibbs J.P., Graeter G.J., Harper E.B., Hocking D.J., Hunter M.L., Patrick D.A., Rittenhouse T.A.G. & Rothermel B.B. (2009) Effects of timber harvest on amphibian populations: understanding mechanisms from forest experiments. BioScience, 59, 853-862.
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This study is summarised as evidence for the following.

	Action	Category
	Leave coarse woody debris in forests Action Link
	Thin trees within forests Action Link

Leave coarse woody debris in forests

A replicated, controlled study in 2003–2009 of 12 ponds in deciduous, pine and mixed-deciduous and coniferous forest in Maine, Missouri and South Carolina, USA (Semlitsch et al. 2009) found that overall, retaining coarse woody debris during clearcutting had a greater negative effect on amphibian population, physiological and behavioural responses than removing debris, when compared to unharvested forest (-32 vs -19%). However, 14 of 33 response variables were less negative, four less positive, three more negative and 12 the same when debris was retained compared to removed, when compared to unharvested controls. Four treatments were assigned to quadrats (2–4 ha) around each breeding pond (4/region): partial harvest (opposite control), clearcut with woody debris retained or removed and an unharvested control. Treatments were applied in 2003–2005. Monitoring was undertaken using drift-fence and pitfall traps, radio-telemetry and in aquatic (200–1,000 Litres) and terrestrial (3 x 3 m or 0.2 m diameter) enclosures. Different species (n = 9) were studied at each of the eight sites. Response variables were abundance, growth, size, survival, breeding success, water loss, emigration and distance moved.

(Summarised by: Rebecca K Smith)
Thin trees within forests

A replicated, controlled study in 2003–2009 of 12 ponds in deciduous, pine and mixed-deciduous and coniferous forest in Maine, Missouri and South Carolina, USA (Semlitsch et al. 2009) found that overall, partially harvesting forest had a negative effect on amphibian population, physiological and behavioural responses, but a smaller negative effect than clearcutting (−7 vs −19 to 32%). Sixteen of 34 response variables were negative, 10 positive and eight the same as unharvested forest. Four treatments were assigned to quadrats (2–4 ha) around each breeding pond (4/region): partial harvest (opposite control; 50–60% reduction), clearcut with coarse woody debris retained or removed and unharvested. Treatments were applied in 2003–2005. Monitoring was undertaken using drift-fence and pitfall traps, radiotelemetry and aquatic (200–1,000 Litres) and terrestrial (3 x 3 m or 0.2 m diameter) enclosures. Different species (n = 9) were studied at each of the eight sites. Response variables were abundance, growth, size, survival, breeding success, water loss, emigration and distance moved.