No abstract

To manage and conserve biodiversity, one must know what is being lost, where, and why, as well as which remedies are likely to be most effective. Metabarcoding technology can characterise the species compositions of mass samples of eukaryotes or of environmental DNA. Here, we validate metabarcoding by testing it against three high-quality standard data sets that were collected in Malaysia (tropical), China (subtropical) and the United Kingdom (temperate) and that comprised 55,813 arthropod and bird specimens identified to species level with the expenditure of 2,505 person-hours of taxonomic expertise. The metabarcode and standard data sets exhibit statistically correlated alpha-and beta-diversities, and the two data sets produce similar policy conclusions for two conservation applications: restoration ecology and systematic conservation planning. Compared with standard biodiversity data sets, metabarcoded samples are taxonomically more comprehensive, many times quicker to produce, less reliant on taxonomic expertise and auditable by third parties, which is essential for dispute resolution.

Climate change and biodiversity loss can be addressed simultaneously by well-planned conservation policies, but this requires information on the alignment of co-benefits under different management actions. One option is to allow forests to naturally regenerate on marginal agricultural land: a key question is whether this approach will deliver environmental co-benefits in an economically viable manner. Here we report on a survey of carbon stocks, biodiversity and economic values from one of the worldâ (tm) s most endemic-rich and threatened ecosystems: the western Andes of Colombia. We show that naturally regenerating secondary forests accumulate significant carbon stocks within 30 years, and support biodiverse communities including many species at risk of extinction. Cattle farming, the principal land use in the region, provides minimal economic returns to local communities, making forest regeneration a viable option despite weak global carbon markets. Efforts to promote natural forest regeneration in the tropical Andes could therefore provide globally significant carbon and biodiversity co-benefits at minimal cost. © 2014 Macmillan Publishers Limited

Federal de Vic ßosa, Vic ßosa, Minas Gerais, Brasil Summary 1. Fragmentation of tropical forests is one of the greatest threats to global biodiversity. Understanding how biological and functional attributes of communities respond to fragmentation and, in turn, whether ecosystem functioning is impacted upon are critical steps for assessing the long-term effects and conservation values of forest fragments. Ecosystem functioning can be inferred through functional diversity metrics, including functional richness, evenness and divergence, which collectively quantify the range, distribution and uniqueness of functional traits within a community. 2. Our study was carried out in forest remnants of the Brazilian Atlantic rain forest, which is a global hotspot of threatened biodiversity that has undergone massive deforestation and fragmentation. We focus on trees, which play critical functional roles in forest structure, food provisioning and carbon storage, to examine community organization and functional diversity across a gradient of fragmentation, from small to large fragments and at edge versus interior habitats. 3. The interiors of small fragments have marginally higher species richness, but similar community structures, to the interiors of bigger fragments. In contrast, fragment edges suffered significant losses of species and changes in community structure, relative to fragment interiors. 4. Despite shifts in community organization, functional richness was not impacted by fragmentation, with the same number of functions provided independent of fragment size or proximity to edge. However, functional evenness and functional divergence both increased with decreasing fragment size, while fragment edges had lower functional evenness than interiors did, indicating that the abundance and dominance of functional traits has changed, with negative implications for functional redundancy and ecosystem resilience. At fragment edges, large-fruited trees, critical as resources for fauna, were replaced by early successional, small-seeded species. The influence of fragment size was smaller, with a reduction in very large-fruited trees in small fragments counterbalanced by increased numbers of fleshy-and medium-fruited trees. Wood density was not impacted by fragmentation. 5. Synthesis. These results suggest that the interiors of even small fragments can contain important biodiversity, ecosystem functions and carbon stores, offering potential opportunities for cobenefits under existing carbon markets. Retaining forest fragments is an important conservation strategy within the highly threatened Brazilian Atlantic forest biome.

Selective logging is a major driver of rainforest degradation across the tropics. Two competing logging strategies are proposed to meet timber demands with the least impact on biodiversity: land sharing, which combines timber extraction with biodiversity protection across the concession; and land sparing, in which higher intensity logging is combined with the protection of intact primary forest reserves. We evaluate these strategies by comparing the abundances and species richness of birds, dung beetles and ants in Borneo, using a protocol that allows us to control for both timber yield and net profit across strategies. Within each taxonomic group, more species had higher abundances with land-sparing than land-sharing logging, and this translated into significantly higher species richness within land-sparing concessions. Our results are similar when focusing only on species found in primary forest and restricted in range to Sundaland, and they are independent of the scale of sampling. For each taxonomic group, land-sparing logging was the most promising strategy for maximizing the biological value of logging operations.

Forests in Southeast Asia are rapidly being logged and converted to oil palm. These changes in land-use are known to affect species diversity but consequences for the functional diversity of species assemblages are poorly understood. Environmental filtering of species with similar traits could lead to disproportionate reductions in trait diversity in degraded habitats. Here, we focus on dung beetles, which play a key role in ecosystem processes such as nutrient recycling and seed dispersal. We use morphological and behavioural traits to calculate a variety of functional diversity measures across a gradient of disturbance from primary forest through intensively logged forest to oil palm. Logging caused significant shifts in community composition but had very little effect on functional diversity, even after a repeated timber harvest. These data provide evidence for functional redundancy of dung beetles within primary forest and emphasize the high value of logged forests as refugia for biodiversity. In contrast, conversion of forest to oil palm greatly reduced taxonomic and functional diversity, with a marked decrease in the abundance of nocturnal foragers, a higher proportion of species with small body sizes and the complete loss of telecoprid species (dung-rollers), all indicating a decrease in the functional capacity of dung beetles within plantations. These changes also highlight the vulnerability of community functioning within logged forests in the event of further environmental degradation.

Summary1. Two strategies are often promoted to mitigate the effects of agricultural expansion on biodiversity: one integrates wildlife-friendly habitats within farmland (land sharing), and the other intensifies farming to allow the offset of natural reserves (land sparing). Their relative merits for biodiversity protection have been subject to much debate, but no previous study has examined whether trade-offs between the two strategies depend on the proximity of farmed areas to large tracts of natural habitat. 2. We sampled birds and dung beetles across contiguous forests and agricultural landscapes (low-intensity cattle farming) in a threatened hotspot of endemism: the Colombian Choc oAndes. We test the hypothesis that the relative biodiversity benefits of either strategy depend partially on the degree to which farmlands are isolated from large contiguous blocks of forest. 3. We show that distance from forest mediates the occurrence of many species within farmland. For the majority of species, occurrence on farmland depends on both isolation from forest and the proportionate cover of small-scale wildlife-friendly habitats within the farm landscape, with both variables having a similar overall magnitude of effect on occurrence probabilities. 4. Simulations suggest that the biodiversity benefits of land sharing decline significantly with increasing distance from forest, but land sparing benefits remain consistent. In farm management units situated close to large contiguous forest (<500 m), land sharing is predicted to provide equal benefits to land sparing, but land sparing becomes increasingly superior in management units situated further from forest (1500 m). The predicted biodiversity benefits of land sparing are similar across all distances, provided that sparing mechanisms genuinely deliver protection for contiguous forest tracts. 5. Synthesis and applications. The persistence of bird and dung beetle communities in lowintensity pastoral agriculture is strongly linked to the proximity of surrounding contiguous forests. Land-sharing policies that promote the integration of small-scale wildlife-friendly habitats might be of limited benefit without simultaneous measures to protect larger blocks of natural habitat, which could be achieved via land-sparing practices. Policymakers should carefully consider the extent and distribution of remaining contiguous natural habitats when designing agri-environment schemes in the tropics.

Commercial selective logging and the conversion of primary and degraded forests to agriculture are the biggest threats to tropical biodiversity. Our understanding of the impacts of these disturbances and the resulting local extinctions on the functional roles performed by the remaining species is limited. We address this issue by examining functional diversity (FD), which quantifies a range of traits that affect a species' ecological role in a community as a single continuous metric. We calculated FD for birds across a gradient of disturbance from primary forest through intensively logged forest to oil palm plantations on previously forested land in Borneo, Southeast Asia, a hotspot of imperilled biodiversity. Logged rainforest retained similar levels of FD to unlogged rainforest, even after two logging rotations, but the conversion of logged forest to oil palm resulted in dramatic reductions in FD. The few remaining species in oil palm filled a disproportionately wide range of functional roles but showed very little clustering in terms of functional traits, suggesting that any further extinctions from oil palm would reduce FD even further. Determining the extent to which the changes we recorded were due to under‐utilization of resources within oil palm or a reduction in the resources present is an important next step. Nonetheless our study improves our understanding of the stability and resilience of functional diversity in these ecosystems and of the implications of land‐use changes for ecosystem functioning.