Co-Benefits of Sustainable Forest Management in Biodiversity Conservation and Carbon Sequestration

Background

Sustainable forest management (SFM), which has been recently introduced to tropical natural production forests, is beneficial in maintaining timber resources, but information about the co-benefits for biodiversity conservation and carbon sequestration is currently lacking.

Methodology/Principal Findings

We estimated the diversity of medium to large-bodied forest-dwelling vertebrates using a heat-sensor camera trapping system and the amount of above-ground, fine-roots, and soil organic carbon by a combination of ground surveys and aerial-imagery interpretations. This research was undertaken both in SFM applied as well as conventionally logged production forests in Sabah, Malaysian Borneo. Our carbon estimation revealed that the application of SFM resulted in a net gain of 54 Mg C ha^-1 on a landscape scale. Overall vertebrate diversity was greater in the SFM applied forest than in the conventionally logged forest. Specifically, several vertebrate species (6 out of recorded 36 species) showed higher frequency in the SFM applied forest than in the conventionally logged forest.

Conclusions/Significance

The application of SFM to degraded natural production forests could result in greater diversity and abundance of vertebrate species as well as increasing carbon storage in the tropical rain forest ecosystems.     

Nitrogen and phosphorus retranslocation and N:P ratios of litterfall in three tropical plantations: luxurious N and efficient P use by Acacia mangium

Some tropical N₂-fixing trees exhibit specific characteristics for phosphorus (P) acquisition and utilisation that contrast with the large nitrogen (N) fluxes in their litterfall. To investigate differences in N and P cycling in N₂-fixing plantations, litterfall and fresh leaf quality of a N₂-fixing Acacia mangium plantation were compared with that of a non-N₂-fixing Swietenia macrophylla plantation and a coniferous Araucaria cunninghamii plantation. The N concentration in the A. mangium litterfall was higher than that in the litterfall of the two other species, whereas the P concentration in the A. mangium leaf litterfall was 0.16 mg g^–1, which was only 12–22% of that of the other species. The P concentration in the reproductive parts of A. mangium was markedly higher (16.1 mg g^–1) than those in the other fractions. The N:P ratio was higher in the leaf fall (81) compared to the fresh leaves (29) of A. mangium, in contrast to the N:P ratios in the leaf samples of the other two species. An analysis of a global litterfall dataset of tropical plantations indicated that N:P ratios in litterfall were significantly higher in N₂-fixers than in non-N₂-fixers, and those of A. mangium were high among species in the N₂-fixer group. These results indicated that A. mangium efficiently retranslocated P in contrast to very large N cycling, under field conditions. These differences may be related to other physiological characteristics of A. mangium.     

Effects of selective logging on tree species diversity and composition of Bornean tropical rain forests at different spatial scales

Reduced-impact logging (RIL) is known to be beneficial in biodiversity conservation, but its effects on tree diversity remain unknown. Pattern of tree diversity following disturbance usually varies with spatial scale of sampling (i.e., plot size). We examined the impacts of RIL on species richness and community composition of tree species at different spatial scales, and the scale (plot size) dependency of the two metrics; species richness versus community similarity. One 2-ha and three to four 0.2-ha plots were established in each of primary, RIL, and conventionally logged (CL) forest in Sabah, Malaysia. Species richness (the number of species per unit number of stems) was higher in the RIL than in the CL forest at both scales. The relationship between species richness and logging intensity varied with plot size. Species richness was greater in the RIL than in the primary forest at the 2-ha scale, while it was similar between the two forests at 0.2-ha scale. Similarly, species richness in the CL forest demonstrated a greater value at the 2-ha scale than at the 0.2-ha scale. Greater species richness in the two logged forests at the 2-ha scale is attributable to a greater probability of encountering the species-rich, small patches that are distributed heterogeneously. Community composition of the RIL forest more resembled that of the primary forest than that of the CL forest, regardless of plot size. Accordingly, species richness is a scale-dependent metric, while community similarity is a more robust metric to indicate the response of tree assemblage to anthropogenic disturbance.