Retain or increase leaf litter or other types of mulch

Overall effectiveness category Awaiting assessment
Number of studies: 2
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Effectiveness

not assessed
Certainty

not assessed
Harms

not assessed

Calculating overall effectiveness category

Background information and definitions

The presence of leaf litter is an important driver of reptile abundance in both temperate (Hu et al. 2013) and tropical forests (Heinen 1992). Adding leaf litter or other mulch to woody crops such as cacao may provide habitat for reptile communities.

For studies that leave woody debris after logging activities or add woody debris to the landscape see Threat: Biological resource use – Leave woody debris in forests after logging, and Habitat restoration and creation – Add woody debris to landscapes.

^{Heinen J.T. (1992) Comparisons of the leaf litter herpetofauna in abandoned cacao plantations and primary rain forest in Costa Rica: some implications for faunal restoration. Biotropica, 24, 431–439.}

^{Hu Y., Urlus J., Gillespie G., Letnic M. & Jessop T.S. (2013) Evaluating the role of fire disturbance in structuring small reptile communities in temperate forests. Biodiversity and Conservation, 22, 1949–1963.}

Study locations

Key messages

Two studies evaluated the effects of retaining or increasing leaf litter or other types of mulch on reptile populations. One study was in Indonesia and one was in Australia.

COMMUNITY RESPONSE (1 STUDY)

Richness/diversity (1 study): One replicated, randomized, controlled, before-and-after study in Indonesia found that reptile species richness increased with the addition of leaf litter and decreased following removal of leaf litter and woody debris.

POPULATION RESPONSE (2 STUDIES)

Abundance (2 studies): Two randomized, controlled studies (one replicated, before-and-after study) in Indonesia and Australia found that the addition of leaf litter or cacao husks resulted in a higher abundance of overall reptiles or skinks. One study also found that removal of leaf litter and woody debris led to a decrease in reptile abundance.

BEHAVIOUR (0 STUDIES)

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

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).
Study and other actions tested
Referenced paper
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.
A randomized controlled study in 2014–2015 in a monoculture cacao farm in North Queensland, Australia (2) found that adding cacao fruit husks underneath cacao trees increased population densities of skinks. Plots of cacao trees with cacao fruit husks had greater densities of skinks (1.1–3.3 skinks/plot) compared to plots without fruit husks (0.3–0.8 skinks/plot). The increased densities of skinks did not reduce the amount of fruit on trees (see original paper for details). The effect of adding cacao fruit husks to the base of trees was monitored on a 1.8 ha monoculture cacao farm. Fourteen plots (15 m apart) were randomly selected, each comprising two adjacent rows of four consecutive flower-bearing trees. In November 2014, seven of the plots had 280 kg of fresh cacao fruit husks left over from processing added underneath all trees (35 kg/tree). A further 15kg/tree of husks were added in December 2014 and January 2015. Visual surveys for skinks were conducted in the mornings every two weeks from December 2014–March 2015.
Study and other actions tested
Referenced paper
Forbes S.J. & Northfield T.D. (2017) Increased pollinator habitat enhances cacao fruit set and predator conservation. Ecological Applications, 27, 887-899.

Please cite as:

Sainsbury K.A., Morgan W.H., Watson M., Rotem G., Bouskila A., Smith R.K. & Sutherland W.J. (2021) Reptile Conservation: Global Evidence for the Effects of Interventions for reptiles. Conservation Evidence Series Synopsis. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

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This Action forms part of the Action Synopsis:

Reptile Conservation

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