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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.

Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha−1 per year (95% CI 0.14–0.72, mean period 1988–2010) in above-ground live biomass carbon. These results closely match those from African and Amazonian plot networks, suggesting that the world’s remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997–1998 El Niño drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere., The existence of a pan-tropical forest carbon sink remains uncertain due to the lack of data from Asia. Here, using direct on-the-ground observations, the authors confirm remaining intact forests in Borneo have provided a long-term carbon sink, but carbon net gains are vulnerable to drought and edge effects.

To evaluate the effectiveness of sustainable forest management (SFM) for wildlife conservation, we investigated the abundances of medium to large ground-dwelling vertebrates in a forest management unit in Borneo by camera trapping. The forest management unit (FMU), Deramakot Forest Reserve (55,083 ha), has applied SFM for the past 15 years. We established 15 plots in preharvested areas and five plots in postharvested areas over the FMU. Plots in the postharvested areas had been subject to reduced-impact logging from 2 to 13 years ago. We obtained photos of ground-dwelling vertebrates with infrared sensor cameras set at 12 random points in each plot. Based on the numbers of photos taken over 770 camera days in each plot, we calculated the mean trapping rate (MTR) of each species for each plot. Over the 20 plots, we obtained 5444 photos of 39 medium-to-large vertebrates (i.e., mammals, birds, and monitor lizards); these included many elusive and endangered species. Among the 39 species, no species showed a significant difference in MTR between the pre- and postharvested areas. Furthermore, species composition was not significantly different between the pre- and postharvested areas. Our results support the idea that implementation of SFM can be an effective investment in wildlife conservation in tropical rainforests.

Borneo has experienced a rapid decline in the extent of forest cover, which has reduced the amount of habitat available for many plant and animal species. The precise impact of habitat loss on the conservation status of dipterocarp trees is uncertain. We use three contrasting techniques, the extent of occurrence, area of occupancy and ecological niche models derived using maxent, in conjunction with a current land-use map of Sabah, to derive estimates of habitat loss and infer a regional IUCN Red List conservation status for 33 Sabah dipterocarp species. Estimates of habitat loss differed significantly according to the methods employed and between species on different habitat types. Proportion of habitat loss determined from the ecological niche models varied from 21 percent for Shorea micans to 99.5 percent for Dipterocarpus lamellatus. Thirty-two of the 33 dipterocarp species analyzed in this study would have their Sabah populations classified as Threatened (equal to a habitat loss of > 30%) under the A2 IUCN Red List criterion. Dipterocarps that occur in lowland forests have experienced greater habitat loss than upland/lower montane or ultramafic species. In addition, species with the lowest predicted area within their historic distributions had the highest proportion of habitat lost, which provides a rationale for targeting conservation effort on the species with narrow distributions. We recommend the ecological niche modeling approach as a rapid assessment tool for reconstructing species’ historic distributions during conservation assessments of tropical trees.

Stable carbon isotope ( δ 13 C) series were developed from analysis of sequential radial wood increments from AD 1850 to AD 2009 for four mature primary rainforest trees from the Danum and Imbak areas of Sabah, Malaysia. The aseasonal equatorial climate meant that conventional dendrochronology was not possible as the tree species investigated do not exhibit clear annual rings or dateable growth bands. Chronology was established using radiocarbon dating to model age–growth relationships and date the carbon isotopic series from which the intrinsic water-use efficiency (IWUE) was calculated. The two Eusideroxylon zwageri trees from Imbak yielded ages of their pith/central wood (±1 sigma) of 670 ± 40 and 759 ± 40 years old; the less dense Shorea johorensis and Shorea superba trees at Danum yielded ages of 240 ± 40 and 330 ± 40 years, respectively. All trees studied exhibit an increase in the IWUE since AD 1960. This reflects, in part, a response of the forest to increasing atmospheric carbon dioxide concentration. Unlike studies of some northern European trees, no clear plateau in this response was observed. A change in the IWUE implies an associated modification of the local carbon and/or hydrological cycles. To resolve these uncertainties, a shift in emphasis away from high-resolution studies towards long, well-replicated time series is proposed to develop the environmental data essential for model evaluation. Identification of old (greater than 700 years) ringless trees demonstrates their potential in assessing the impacts of climatic and atmospheric change. It also shows the scientific and applied value of a conservation policy that ensures the survival of primary forest containing particularly old trees (as in Imbak Canyon and Danum).

The carbon storage and conservation value of old-growth tropical forests is clear, but the value of logged forest is less certain. Here we analyse >100,000 observations of individuals from 11 taxonomic groups and >2,500 species, covering up to 19 years of post-logging regeneration, and quantify the impacts of logging on carbon storage and biodiversity within lowland dipterocarp forests of Sabah, Borneo. We estimate that forests lost ca. 53% of above-ground biomass as a result of logging but despite this high level of degradation, logged forest retained considerable conservation value: floral species richness was higher in logged forest than in primary forest and whilst faunal species richness was typically lower in logged forest, in most cases the difference between habitats was no greater than ca. 10%. Moreover, in most studies >90% of species recorded in primary forest were also present in logged forest, including species of conservation concern. During recovery, logged forest accumulated carbon at five times the rate of natural forest (1.4 and 0.28 Mg C ha−1 year−1, respectively). We conclude that allowing the continued regeneration of extensive areas of Borneo’s forest that have already been logged, and are at risk of conversion to other land uses, would provide a significant carbon store that is likely to increase over time. Protecting intact forest is critical for biodiversity conservation and climate change mitigation, but the contribution of logged forest to these twin goals should not be overlooked.

Tropical forests sequester a large amount of carbon in the vegetation and soils (approximately 25 % of the carbon in the terrestrial ecosystems) (Bonan 2008). The conversion of tropical forests through forestry and land-use change results in an enormous emission of carbon to the atmosphere. In the past decade, deforestation and forest degradation in Southeast Asia and elsewhere in the tropics accounted for approximately 20 % of global anthropogenic carbon emissions (Gullison et al. 2007). The important roles of natural tropical forests in carbon storage and climate change mitigation are increasingly recognized.

Comparisons between the consequences of improved management and those of conventional logging in terms of carbon stock and biodiversity conservation were conducted in the Deramakot Forest Reserve versus the Tangkulap Forest Reserve, where lowland dipterocarp forest is the natural vegetation (see also Imai et al. 2009). In this chapter, we summarize the co-benefits of improved forest management for biodiversity conservation and carbon sequestration. We evaluate the co-benefits in terms of additionality, which is the net increment effect of the improved forest management added over 13 years from 1989 (when logging was suspended in Deramakot) until 2002 (when our analyses started) in comparison to continued high-impact conventional logging.

The Deramakot Forest Reserve and the Tangklap Forest Reserve, where the ecological studies described in this book were conducted, are located in the interior of the state of Sabah, Malaysia (north Borneo) (Fig. 1.1). In Sabah, forested lands, including both natural and planted forests, are found mainly within areas designated by law as Forest Reserve, State Park, or Wildlife Sanctuary. Together these three classes of forest lands account for 53 % (3.87 million ha) of Sabah’s landmass, and are collectively referred to as the Permanent Forest Estate (PFE). Little native forest is currently left outside the boundaries of the PFE. Forest Reserve is managed under the Sabah Forestry Department and is designated by law primarily to produce timber from natural forests. Despite declining timber output, forestry remains a dominant land use in Sabah.

Selective logging of tropical forests imposes spatial pattern on the landscape by creating a mosaic of patches affected by different intensities of disturbance. To understand the ecological impacts of selective logging it is therefore necessary to explore how patterns of tree species composition are affected by this patchy disturbance. This study examines the impacts of selective logging on species composition and spatial patterns of vegetation structure and tree diversity in Sabah, Borneo. We compare tree diversity between logged and unlogged forest at three scales: species richness within plots, species turnover among plots, and total species richness and composition of plots combined. Logging had no effect on tree diversity measured at the smallest scale. Logged forest had a greater rate of species turnover with distance, so at a large spatial scale it supported more tree species than the relatively homogeneous unlogged area. Tree species composition also differed significantly between the two types of forest, with more small dipterocarps and large pioneers in logged forest, and more large dipterocarps in unlogged forest. Our results emphasize the importance of sampling at a sufficiently large scale to represent patterns of biodiversity within tropical forest landscapes. Large areas of production forest in SE Asia are threatened with conversion to commercial crops; our findings show that selectively logged forest can retain considerable conservation value.