Conservation value of cacao agroforestry for amphibians and reptiles in South-East Asia: combining correlative models with follow-up field experiments

Published source details Wanger T.C., Saro A., Iskandar D.T., Brook B.W., Sodhi N.S., Clough Y. & Tscharntke T. (2009) Conservation value of cacao agroforestry for amphibians and reptiles in South-East Asia: combining correlative models with follow-up field experiments. Journal of Applied Ecology, 46, 823-832.
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This study is summarised as evidence for the following.

	Action	Category
	Retain or increase leaf litter or other types of mulch Action Link
	Add woody debris to landscapes Action Link
	Create refuges Action Link
	Leave coarse woody debris in forests Action Link

Retain or increase leaf litter or other types of mulch

A replicated, randomized, controlled, before-and-after study in 2007–2008 in cacao plantations Sulawesi, Indonesia (1) found that both reptile abundance and species richness increased after the addition of leaf litter and decreased following the combined removal of woody debris and leaf litter. All results were reported as statistical model outputs. Overall reptile abundance increased when leaf litter was added but decreased after leaf litter and woody debris were removed, or when only woody debris was removed (see original paper for details of individual species abundance changes). Reptile species richness increased after leaf litter was added and decreased after leaf litter and woody debris were removed. Forty-two plots (40 x 40 m²) in cacao plantations (number not specified) were randomly divided into seven treatments: removal and addition of leaf litter, removal and addition of woody debris (trunks and branch piles), removal and addition of woody debris plus leaf litter and no management (6 replicates of each treatment). Plots were sampled 26 days before and 26 days after habitat manipulation, three times a day in December 2007–July 2008. Active visual surveys were undertaken for 25 minutes along both plot diagonals (transects 3 x 113 m).

(Summarised by: Maggie Watson, Katie Sainsbury)
Add woody debris to landscapes

A replicated, randomized, controlled, before-and-after study in 2007–2008 in cacao plantations Sulawesi, Indonesia (Wanger et al. 2009) found that after woody debris, or debris and leaf litter, were added to plantations, both reptile abundance and species richness did not increase compared to in areas where no debris and/or leaf litter was added. All results were reported as statistical model outputs. Overall reptile abundance remained similar after woody debris or debris and leaf litter was added, but decreased after leaf litter and woody debris were removed, or when only woody debris was removed (see original paper for details of individual species abundance changes). Reptile species richness also remained similar after the addition of woody debris or debris and leaf litter, but decreased after leaf litter and woody debris were removed. Six plots (40 x 40 m²) each in cacao plantations (number not specified) were randomly treated with: addition or removal of woody debris (trunks and branch piles), addition or removal of woody debris plus leaf litter or no management. Plots were sampled 26 days before and 26 days after habitat manipulation, three times a day in December 2007–July 2008. Active visual surveys were undertaken for 25 minutes along both plot diagonals (transects 3 x 113 m).

(Summarised by: Maggie Watson, Katie Sainsbury)
Create refuges

A replicated, controlled, before-and-after study in 2007–2008 of a cacao plantation in Sulawesi, Indonesia (Wanger et al. 2009) found that adding woody debris and/or leaf litter to plots had no effect on overall amphibian abundance or species richness. However, following addition of woody debris plus leaf litter, Hylarana celebensis abundance increased and Asian toad Duttaphrynus melanostictus decreased. Forty-two plots (40 x 40 m²) were divided into four treatments: addition of woody debris (trunks and branch piles), addition of leaf litter, addition of woody debris plus leaf litter and an unmanipulated control. Monitoring was undertaken twice 26 days before and twice 26 days after habitat manipulation. Visual surveys were undertaken along both plot diagonals (transects 113 x 3 m).
Leave coarse woody debris in forests

A replicated, controlled, before-and-after study in 2007–2008 of a cacao plantation in Sulawesi, Indonesia (Wanger et al. 2009) found that removal of woody debris and/or leaf litter did not significantly effect overall amphibian abundance, but did decrease species richness. However, the abundance of Hylarana celebensis and Asian toad Duttaphrynus melanostictus increased following removal of woody debris and leaf litter. The abundance of Sulawesian toad Ingerophrynus celebensis decreased following removal of woody debris. Forty-two plots (40 x 40 m²) were divided into four treatments: removal of woody debris (trunks and branch piles), removal of leaf litter, removal of woody debris plus leaf litter and an unmanipulated control. Monitoring was undertaken twice on two occasions, 26 days before and 26 days after habitat manipulation. Visual surveys were undertaken along both plot diagonals (transects 3 x 113 m).

(Summarised by: Rebecca K Smith)