Would protecting tropical forest fragments provide carbon and biodiversity cobenefits under REDD+?

Abstract

Tropical forests store vast amounts of carbon and are the most biodiverse terrestrial habitats, yet they are being converted and degraded at alarming rates. Given global shortfalls in the budgets required to prevent carbon and biodiversity loss, we need to seek solutions that simultaneously address both issues. Of particular interest are carbon-based payments under the Reducing Emissions from Deforestation and Forest Degradation (REDD+) mechanism to also conserve biodiversity at no additional cost. One potential is for REDD+ to protect forest fragments, especially within biomes where contiguous forest cover has diminished dramatically, but we require empirical tests of the strength of any carbon and biodiversity cobenefits in such fragmented systems. Using the globally threatened Atlantic Forest landscape, we measured above-ground carbon stocks within forest fragments spanning 13 to 23 442 ha in area and with different degrees of isolation. We related these stocks to tree community structure and to the richness and abundance of endemic and IUCN Red-listed species. We found that increasing fragment size has a positive relationship with above-ground carbon stock and with abundance of IUCN Red-listed species and tree community structure. We also found negative relationships between distance from large forest block and tree community structure, endemic species richness and abundance, and IUCN Red-listed species abundance. These resulted in positive congruence between carbon stocks and Red-listed species, and the abundance and richness of endemic species, demonstrating vital cobenefits. As such, protecting forest fragments in hotspots of biodiversity, particularly larger fragments and those closest to sources, offers important carbon and biodiversity cobenefits. More generally, our results suggest that macroscale models of cobenefits under REDD+ have likely overlooked key benefits at small scales, indicating the necessity to apply models that include finer-grained assessments in fragmented landscapes rather than using averaged coarse-grained cells.

High Carbon Stock forests provide co‐benefits for tropical biodiversity

“…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.…”

Seed size predicts community composition and carbon storage potential of tree communities in rain forest fragments in India's Western Ghats

“…; Magnago et al . ). Given that the above‐ground vegetation of tropical forests constitutes a large carbon pool which regulates atmospheric CO 2 levels and global climate (Malhi, Baldocchi & Jarvis ), understanding how fragmentation‐driven shifts in the composition of tree communities in turn affect their ability to store carbon is becoming increasingly important.…”

Gross changes in forest area shape the future carbon balance of tropical forests

“…Accurate estimates of LULCC carbon fluxes in the neotropical forests are increasingly important for climate mitigation policy with the progressive implementation of Reducing Emissions from Deforestation and forest Degradation (REDD+) programs under the United Nations Framework Convention on Climate Change (UNFCCC) (Angelsen et al, 2009;Magnago et al, 2015). Furthermore, forest-based climate mitigation has been taken as a key option in the nationally determined contributions proposed by some countries to the Paris Climate Agreement, accounting for about onefourth of total intended emission reductions from a predefined baseline (Grassi et al, 2017).…”