Quantifying mammal biodiversity co‐benefits in certified tropical forests

Abstract

Aim Financial incentives to manage forests sustainably, such as certification or carbon storage payments, are assumed to have co‐benefits for biodiversity conservation. This claim remains little studied for rain forest mammals, which are particularly threatened, but challenging to survey. Location Sabah, Malaysia, Borneo. Methods We used photographic data from three commercial forest reserves to show how community occupancy modelling can be used to quantify mammalian diversity conservation co‐benefits of forest certification. These reserves had different management histories, and one was certified by the Forest Stewardship Council. Results Many threatened species occupied larger areas in the certified reserve. Species richness, estimated per 200 × 200‐m grid cell throughout all reserves, was higher in the certified site, particularly for threatened species. The certified reserve held the highest aboveground biomass. Within reserves, aboveground biomass was not strongly correlated with patterns of mammal richness (Spearman's rho from 0.03 to 0.32); discrepancies were strongest along reserve borders. Main conclusions Our approach provides a flexible and standardized tool to assess biodiversity and identify winners of sustainable forestry. Inferring patterns of species richness from camera‐trapping carries potential for the objective designation of high conservation value forest. Correlating species richness with aboveground biomass further allows evaluating the biodiversity co‐benefits of carbon protection. These advantages make the present approach an ideal tool to overcome the difficulties to rigorously quantify biodiversity co‐benefits of forest certification and carbon storage payments.

High Carbon Stock forests provide co‐benefits for tropical biodiversity

“…Similarly, Sollmann et al. () found little correspondence between above‐ground biomass and mammal occupancy in a certified forest reserve in Malaysian Borneo, despite adopting a comparable methodology to the present study. Contrasting findings may be attributed to spatial variability in hunting pressure.…”

“…The extent to which biodiversity and carbon spatially align is fundamental to our understanding of whether carbon‐based policies can deliver positive results for conservation in human‐modified landscapes. Among the few studies that assess biodiversity and carbon covariance using primary and/or high‐resolution data (Magnago et al., ; Sollmann et al., ), ours is the first to verify an association within a tropical landscape mosaic undergoing certification. We show that the strength, nature and extent of biodiversity co‐benefits are dependent on how carbon stocks are characterised (i.e.…”

“…Researchers predominantly rely on coarse species range delineations, which are fraught with uncertainty (Rodríguez‐Castañeda, Hof, Jansson, & Harding, ) and may not account for localised extirpation due to anthropogenic pressure (Harrison et al., ). Despite statistical advances that account for imperfect detection in biodiversity indices (Royle & Dorazio, ), these methods have received relatively limited application in a co‐benefits context (but see Gilroy et al., ; Sollmann et al., ), resulting in possible underestimates of species assemblages. Consequently, biodiversity co‐benefits assessments at local‐scales, using primary, fine‐grained data would provide valuable policy insights.…”

Identifying conservation priorities in a defaunated tropical biodiversity hotspot

“…Multispecies occupancy models offer an analytical framework to address this challenge, as species with few detections borrow information from more abundant species, which improves precision of the parameter estimates for rare species (Drouilly, Clark, & O'Riain, 2018;Li, Bleisch, & Jiang, 2018;Tobler, Hartley, Carrillo-Percastegui, & Powell, 2015). Because species-specific responses to covariates can be projected to unsampled areas, this approach can be used to generate maps of species potential occurrence (MacKenzie et al, 2017;Sollmann et al, 2017).…”

Human disturbance impacts on rainforest mammals are most notable in the canopy, especially for larger‐bodied species

“…Consequently, to date there have been no direct comparisons using camera traps to test whether terrestrial and canopy mammal communities respond to rainforest disturbance in a similar way—although previous work has compared arboreal camera trapping with terrestrial transects (e.g., Bowler et al, , Whitworth et al, ). In this study, we use multispecies occupancy models, which are well suited to analysis of camera data at the community level (Tobler et al, ) and for assessing species‐specific responses to varying levels of forest disturbance (Bowler et al, ; Sollmann et al, ; Tobler et al, ), to answer the question of whether arboreal rainforest mammals show a greater sensitivity to forest habitat degradation compared with their terrestrial counterparts.…”