Managing Neotropical oil palm expansion to retain phylogenetic diversity

The taxonomic, functional and phylogenetic diversity of birds in Xiaohongxiang Wetland, southwest China

Small wetlands are essential for preserving global biodiversity, yet they are frequently neglected in conservation strategies due to vague definitions and a lack of research attention. In this study, we conducted thirty-six surveys via the point count method in the Xiaohongxiang Wetland, Anning City, Yunnan Province, China, from November 2023 to June 2024. We aimed to evaluate the impact of various habitats surrounding Xiaohongxiang Wetland (wetlands, villages, farmlands, cherry plantations and pine forests) on the taxonomic, functional and phylogenetic diversity of avian species and investigate the significance of these habitats for ecological conservation and restoration efforts. A total of 62 species were recorded. Small wetlands are vital for supporting common waterbirds, but may not safeguard rare species effectively. While cherry plantations and pine forests enhance avian diversity near wetlands, their low functional diversity could limit the ecological niches available to birds. This indicates that monoculture plantations might restrict the habitat variety needed for a diverse bird community. Our study found no clear phylogenetic clustering or overdispersion amongst bird species across habitats, suggesting that community assembly is shaped by competitive exclusion, habitat filtering and neutral processes. Despite a limited sample size, our results highlight a gap between taxonomic and functional diversity, indicating that multidimensional biodiversity metrics are essential for thoroughly evaluating wetland restoration and habitat impacts on bird diversity.

Woody species composition, diversity, and ecosystem services of yards along an urban socioeconomic gradient

Woody plants offer a wide range of valuable ecosystem services, but their distribution across socioeconomic gradients in urban landscapes remains poorly understood. Thus, we explored the effect of socioeconomic and legacy factors on plant species richness and phylogenetic diversity, and the motivations for growing and keeping certain species. We sampled a total of 300 households across a socioeconomic gradient in the city of Harare, Zimbabwe, in high-, medium- and low-density areas, representing low to high wealth strata. Trees were mostly grown for ornamental purpose in the rich (low-density) suburbs and utilitarian purposes in the poorer medium to high-density areas. However, trees were also grown with similar proportion for shade across the socioeconomic gradient. Proportion of medicinal and fruit trees increased with household density, while wind break trees were more common in low-density suburbs. Exotic species exhibited greater species richness compared with indigenous species, with both combined and separate assessments of indigenous and exotic species richness revealing a significant positive association with socioeconomic and legacy factors. The composition of species displayed considerable variation along the socioeconomic gradient. Notably, in low-density environments, exotic species maintained elevated phylogenetic diversity in comparison to indigenous species. This distinction was particularly pronounced when analysed independently, revealing a significant positive correlation between exotic species richness and both property value and education level. Our study shows that residents filter specific plant species based on their socioeconomic status and that, relative to low-income households, the rich homeowners have unintentionally incorporated enough exotic species to produce novel phylogenetic diversity of woody plants in their yards. Thus, we confirm the existence of a socioeconomic gradient in terms of species richness, composition, and phylogenetic diversity. However, the imbalance in species richness and phylogenetic diversity across the socioeconomic gradient can be reduced by increased tree planting in open areas, including along streets in medium to high-density areas to improve ecosystem services.

Functional and phylogenetic diversity of an agricultural matrix avifauna: The role of habitat heterogeneity in Afrotropical farmland

Varied strategies to alleviate the loss of farmland biodiversity have been tested, yet there is still insufficient evidence supporting their effectiveness, especially when considering phylogenetic and functional diversity alongside traditional taxonomic diversity metrics. This conservation challenge is accentuated in the Afrotropics by the rapid agricultural expansion and intensification for the production of cash crops and by a comparative lack of research. In this study, we assessed how farming practices influence avian phylogenetic and functional diversity. We conducted point-count surveys to assess avian diversity in monocultures of tea and mixed crop farming systems surrounding the Nyungwe rainforest in south-west Rwanda, allowing us to investigate the drivers of avian diversity at farm level. Species composition was found to be moderately different between farm types, with mixed crop farms supporting higher phylogenetic diversity than tea plantations. There were no significant seasonal differences in species composition, functional or phylogenetic diversity. Overall, functional diversity did not differ between farm types, but the dispersion of trophic-related traits was significantly higher in mixed crop farms. Both functional and phylogenetic diversity were influenced by floristic diversity, vegetation height, tree number, and elevation to varying degrees. Our results also (i) highlight the role of farmland heterogeneity (e.g., crop species composition, height, and tree cover extent) in encouraging avian functional and phylogenetic diversity in the Afrotropics and (ii) indicate that the generally negative biodiversity impacts of monoculture agriculture can be partially alleviated by extensive agroforestry with an emphasis on indigenous tree species.

Exploring the relationship between soil and plant evolutionary diversity in the Roraima table mountain OCBIL, Guayana Highlands

OCBIL theory aims to develop hypotheses that explain the evolutionary ecology of biota on old, climatically buffered, infertile landscapes (OCBILs). The table mountain OCBILs of the Guayana Highlands are a major centre of Neotropical plant diversity; however, knowledge about the underlying mechanisms of plant community assembly at the mountaintops is still limited. We evaluated the effect of a fine-scale geoenvironmental gradient on the phylogenetic metrics of plant communities on the iconic, highly isolated Roraima table mountain of the Guayana Highlands. We selected three specific geoenvironments: Bonnetia-shrubby rupestrian grassland, peaty rupestrian grassland and sandy rupestrian grassland. We evaluated evolutionary history using species richness and phylogenetic metrics and analysed effects of the soil on phylogenetic metrics using linear models. Of the 55 species surveyed, 40% are endemic to the Guayana Highlands. Bonnetia-shrubby rupestrian grassland showed higher species richness (47) than peaty rupestrian grassland (30) and sandy rupestrian grassland (24). We observed significant differences in phylogenetic diversity and structure among geoenvironments. The highest phylogenetic diversity was found for Bonnetia-shrubby rupestrian grassland and sandy rupestrian grassland. Peaty rupestrian grassland had significantly lower mean pairwise phylogenetic distance and all standardized phylogenetic metrics. The values of standardized phylogenetic metrics were close to zero, suggesting random phylogenetic structure. The linear models revealed that soil texture explained most of the variation in phylogenetic metrics. Our results might be related to the long geological history of tepuis and the accumulation of lineages over tens of millions of years, which supports the OCBIL theory.

Replacing low-intensity cattle pasture with oil palm conserves dung beetle functional diversity when paired with forest protection

Meeting rising demand for oil palm whilst minimizing the loss of tropical biodiversity and associated ecosystem functions is a core conservation challenge. One potential solution is focusing the expansion of high-yielding crops on presently low-yielding farmlands alongside protecting nearby tropical forests that can enhance provision of ecosystem functions. A key question is how this solution would impact invertebrate functional diversity. We focus on oil palm in the Colombian Llanos, where plantations are replacing improved cattle pastures and forest fragments, and on dung beetles, which play key functional roles in nutrient cycling and secondary seed dispersal. We show that functional richness and functional diversity of dung beetles is greater in oil palm than in cattle pasture, and that functional metrics did not differ between oil palm and remnant forest. The abundance-size class profile of dung beetles in oil palm was more similar to forest than to pasture, which had lower abundances of the smallest and largest dung beetles. The abundance of tunneling and rolling dung beetles did not differ between oil palm and forest, while higher forest cover increased the abundance of diurnal and generalist-feeding beetles in oil palm landscapes. This suggests that prioritizing agricultural development on low-yielding cattle pasture will have positive effects on functional diversity and highlights the need for forest protection to maintain ecosystem functioning within agricultural landscapes.

Conserving predators across agricultural landscapes in Colombia: habitat use and space partitioning by jaguars, pumas, ocelots and jaguarundis

Loss and degradation of natural habitats continue to increase across the tropics as a result of agricultural expansion. Consequently, there is an urgent need to understand their effects, and the distribution and habitat requirements of wildlife within human-modified landscapes, to support the conservation of threatened species, such as felids. We combined camera trapping and land cover data into occupancy models to study the habitat use and space partitioning by four sympatric felid species in an agricultural landscape in Colombia. Land use in the area includes cattle ranching and oil palm cultivation, the latter being an emerging land use type in the Neotropics. Factors determining species occupancy were the presence of wetlands for jaguars (positive effect); water proximity for pumas (positive effect); and presence of pastures for ocelots and jaguarundis (negative effect). Only ocelots were occasionally recorded in oil palm areas. Our results suggest that to align development with the conservation of top predators it is crucial to maintain areas of forest and wetland across agricultural landscapes and to restrict agricultural and oil palm expansion to modified areas such as pastures, which are of limited conservation value. Because there is no spatial segregation between the felid species we studied, conservation strategies that benefit all of them are possible even in modified landscapes.

The effects of restoring logged tropical forests on avian phylogenetic and functional diversity

Selective logging is the most prevalent land-use change in the tropics. Despite the resulting degradation of forest structure, selectively logged forests still harbor a substantial amount of biodiversity leading to suggestions that their protection is the next best alternative to conserving primary, old-growth forests. Restoring carbon stocks under Reducing Emissions from Deforestation and Forest Degradation (REDD+) schemes is a potential method for obtaining funding to protect logged forests, via enrichment planting and liberation cutting of vines. This study investigates the impacts of restoring logged forests in Borneo on avian phylogenetic diversity, the total evolutionary history shared across all species within a community, and on functional diversity, with important implications for the protection of evolutionarily unique species and the provision of many ecosystem services. Overall and understorey avifaunal communities were studied using point count and mist netting surveys, respectively. Restoration caused a significant loss in phylogenetic diversity and MPD (mean pairwise distance) leaving an overall bird community of less total evolutionary history and more closely related species compared to unlogged forests, while the understorey bird community had MNTD (mean nearest taxon distance) that returned toward the lower levels found in a primary forest, indicating more closely related species pairs. The overall bird community experienced a significant loss of functional strategies and species with more specialized traits in restored forests compared to that of unlogged forests, which led to functional clustering in the community. Restoration also led to a reduction in functional richness and thus niches occupied in the understorey bird community compared to unlogged forests. While there are additional benefits of restoration for forest regeneration, carbon sequestration, future timber harvests, and potentially reduced threat of forest conversion, this must be weighed against the apparent loss of phylogenetic and functional diversity from unlogged forest levels, making the biodiversity-friendliness of carbon sequestration schemes questionable under future REDD+ agreements. To reduce perverse biodiversity outcomes, it is important to focus restoration only on the most degraded areas or at reduced intensity where breaks between regimes are incorporated.