Thresholds for adding degraded tropical forest to the conservation estate.

Logged and disturbed forests are often viewed as degraded and depauperate environments compared with primary forest. However, they are dynamic ecosystems that provide refugia for large amounts of biodiversity , so we cannot afford to underestimate their conservation value . Here we present empirically defined thresholds for categorizing the conservation value of logged forests, using one of the most comprehensive assessments of taxon responses to habitat degradation in any tropical forest environment. We analysed the impact of logging intensity on the individual occurrence patterns of 1,681 taxa belonging to 86 taxonomic orders and 126 functional groups in Sabah, Malaysia. Our results demonstrate the existence of two conservation-relevant thresholds. First, lightly logged forests (<29% biomass removal) retain high conservation value and a largely intact functional composition, and are therefore likely to recover their pre-logging values if allowed to undergo natural regeneration. Second, the most extreme impacts occur in heavily degraded forests with more than two-thirds (>68%) of their biomass removed, and these are likely to require more expensive measures to recover their biodiversity value. Overall, our data confirm that primary forests are irreplaceable , but they also reinforce the message that logged forests retain considerable conservation value that should not be overlooked.

Project(s)

Priority 5: Enhanced Partnerships

Stability of Altered Forest Ecosystems Project

Funder

Funder name	Awards
Yayasan Sime Darby, Malaysia	Stability of Altered Forest Ecosystems Project
NOMIS Stiftung, Switzerland
Australian Research Council, Australia	Grant DP140101541
Bat Conservation International, United States
British Council, United Kingdom	Newton-Ungku Omar Fund 216433953
British Ecological Society, United Kingdom	Grant 3256/4035
Cambridge Trust, United Kindom
Cambridge University Commonwealth Fund, United Kingdom
Grantová Agentura České Republiky, Czechia	14-32302S
European Research Council, European Union	281986
European Social Fund Plus, European Union / Government of the Czech Republic	CZ.1.07/2.3.00/20.0064
Ministry of Higher Education, Malaysia, Malaysia	Fundamental Research Grant Scheme (FRG0302-STWN-1/ 2011)
Česká Zemědělská Univerzita v Praze, Czechia	FFWS (IGA number A_26_22)
Jardine Foundation
Malaysia Industry Group for High Technology	216433953
Ministerstvo Školství, Mládeže a Tělovýchovy, Czechia	INTER-TRANSFER LTT19018
Panton Trust, United Kingdom
Primate Society of Great Britain. United Kingdom
ProForest, United Kingdom
Royal Society, United Kingdom	Grant RG130793
S.T. Lee Fund
Sir Philip Reckitt Educational Trust
Tim Whitmore Fund, United Kingdom
Universiti Malaysia Sabah. Malaysia
University of East Anglia, United Kingdom
University of Kent, United Kingdom
Institute of Food and Agricultural Sciences, University of Florida, United States
Natural Environment Research Council, United States	NE/H011307/1 - NE/K016253/1 - NE/K016407/1 - NE/K016148/1 - NE/K0106261/1 - NE/K015377/1 - NE/L002515/1 - NE/L002582/1 - NE/P00363X/1 - Studentship 1122589
Varley-Gradwell Travelling Fellowship in Insect Ecology, United Kingdom	Travelling Fellowship
World Wildlife Fund, United States