PhD project: Understanding covariation between mammalian diversity and forest carbon across a human-modified tropical landscape
Tropical forests account for 7% of the world’s terrestrial surface area, yet they sustain half of the planet’s biodiversity, and provide vital products and services at a global scale. As the sphere of anthropogenic influence continues to expand, natural tropical forests are being displaced by human-modified landscapes, resulting in biodiversity loss and the potential breakdown of ecosystem services. Ecosystem service-orientated policies, such as REDD+, have emerged as a popular strategy to mitigate tropical forest loss and seek to assign economic value to natural capital, thus providing financial incentives for conservation. One key assumption of REDD+ is the delivery of ecological co-benefits, whereby forest protection/restoration to enhance carbon stocks will also conserve biodiversity. Global-scale analyses have highlighted the potential for tropical regions to deliver win–win conservation outcomes, yet coarse-scale methodologies that have been adopted mask local variation. Consequently, further investigation is required to determine spatial concordance between ecosystem services and biodiversity at the scale of a typical conservation management unit.
Medium to large terrestrial mammals represent a model study system for such an investigation since they have substantial ecological roles in tropical forest ecosystems, are frequently prioritised by conservation assessments, and can serve as flagship species to reflect the needs of other taxa. Furthermore, their numerical and distributional spatial signatures over a landscape may reflect a cause or effect of compromised ecosystem functioning. Nick’s PhD research will address these concerns by assessing the spatial congruence between mammalian diversity and forest carbon stocks at a fine landscape scale. In so doing, he aims to understand the ecological response of tropical forest mammals to a gradient of landscape disturbance, but also the extent to which this variation in mammal diversity is associated with the carbon provisions prioritised by REDD+ policies.
The study is based at the Stability of Altered Forest Ecosystems project (www.safeproject.net) in Sabah, Malaysian Borneo, in collaboration with the Southeast Asian Rainforest Research Programme, The Forest Trust Indonesia and colleagues at Universiti Malaysia Sabah and Imperial College London. Nick is instigating a camera trapping and acoustic monitoring campaign at SAFE and the wider landscape to test for covariation between biodiversity and carbon stocks. This dataset will also be used in additional analyses concerning connectivity and spatial planning for the landscape. His work is part of the NERC Human-Modified Tropical Forest Programme (http://lombok.hmtf.info/).
Nick Deere is a member of the Durrell Institute of Conservation and Ecology.
NERC-CASE studentship with SEARRP, via the Enveast Doctoral Training Programme
NERC Human-Modified Tropical Forest Programme (http://lombok.hmtf.info/)
Runting, R. et al. (2019). Larger gains from improved management over sparing–sharing for tropical forests. Nature Sustainability [Online] 2:53-61. Available at: https://doi.org/10.1038/s41893-018-0203-0.Tropical forests are globally significant for both biodiversity conservation and the production of economically valuable wood products. Two contrasting approaches have been suggested to simultaneously produce timber and conserve biodiversity; one partitions forests to deliver these objectives separately (sparing), the other integrates both objectives in the same location (sharing). To date, the ‘sparing or sharing’ debate has focused on agricultural landscapes, with scant attention paid to forest management. Here we explored the sparing-to-sharing continuum through spatial optimisations with set economic returns for the forests of East Kalimantan, Indonesia – a global biodiversity hotspot. We found that neither sparing nor sharing extremes are optimal, although the greatest conservation value was attained towards the sparing end of the continuum. Critically, improved management strategies, such as reduced-impact logging, accounted for larger conservation gains than altering the balance between sparing and sharing, particularly for endangered species. Ultimately, debating sparing versus sharing has limited value while large gains remain from improving forest management.
Boron, V. et al. (2019). Richness, diversity, and factors influencing occupancy of mammal communities across human-modified landscapes in Colombia. Biological Conservation [Online] 232:108-116. Available at: https://doi.org/10.1016/j.biocon.2019.01.030.As human-modified landscapes are increasing in the tropics, it becomes critical to understand how they affect mammal communities to reconcile conservation and development. We combined land cover information and camera-trapping data to explore the effects of agricultural expansion on mammals in the Magdalena river valley of Colombia. We estimated species diversity, evenness, and dominance across two agricultural landscapes, modified by cattle ranching and oil palm cultivation. We further assessed which variables influence species- and community-level occupancy using multi-species occupancy models. Results highlight that modified landscapes display lower species richness, diversity and evenness, and higher dominance than more pristine sites. Residual forest cover and distance to water had significant effect on community occupancy (positive and negative respectively). Forests were particularly important for pumas, ocelots, lowland pacas, Central American agoutis, and crab-eating raccoons while wetlands had a positive effect on jaguars, the apex predator in the region. The influence of anthropogenic pressure was not clearly evident, though pastures were not valuable habitats for any mammal species, as they had a negative, yet not significant, effect on species and community occupancy. In light of rapidly expanding agriculture across the tropics, our findings highlight species-specific responses to disturbance that can inform land use planning and conservation policies. We stress the conservation value of forest and wetland habitat to mammal occupancy in heterogeneous ecosystems. Moreover, our results demonstrate that oil palm and crop expansion should target existing pastures, which displayed limited conservation value for Neotropical mammals but occupy vast swathes of land across Latin America.
Struebig, M. et al. (2018). Addressing human-tiger conflict using socio-ecological information on tolerance and risk. Nature Communications [Online] 9. Available at: https://www.nature.com/articles/s41467-018-05983-y.Tigers are critically endangered due to deforestation and persecution. Yet in places, Sumatran tigers (Panthera tigris sumatrae) continue to coexist with people, offering insights for managing wildlife elsewhere. Here, we couple spatial models of encounter risk with information on tolerance from 2,386 Sumatrans to reveal drivers of human-tiger conflict. Risk of encountering tigers was greater around populated villages that neighbored forest or rivers connecting tiger habitat; geographic profiles refined these predictions to three core areas. People’s tolerance for tigers was related to underlying attitudes, emotions, norms and spiritual beliefs. Combining this information into socio-ecological models yielded predictions of tolerance that were 32 times better than models based on social predictors alone. Pre-emptive intervention based on these socio-ecological predictions could have averted up to 51% of attacks on livestock and people, saving 15 tigers from the wild. Our work provides further evidence of the benefits of interdisciplinary research on conservation conflicts.
Marchant, R. et al. (2018). Drivers and trajectories of land cover change in East Africa: Human and environmental interactions from 6000 years ago to present. Earth-Science Reviews [Online] 178:322-378. Available at: https://doi.org/10.1016/j.earscirev.2017.12.010.East African landscapes today are the result of the cumulative effects of climate and land-use change over millennial timescales. In this review, we compile archaeological and palaeoenvironmental data from East Africa to document land-cover change, and environmental, subsistence and land-use transitions, over the past 6000?years. Throughout East Africa there have been a series of relatively rapid and high-magnitude environmental shifts characterised by changing hydrological budgets during the mid- to late Holocene. For example, pronounced environmental shifts that manifested as a marked change in the rainfall amount or seasonality and subsequent hydrological budget throughout East Africa occurred around 4000, 800 and 300 radiocarbon years before present (yr BP). The past 6000?years have also seen numerous shifts in human interactions with East African ecologies. From the mid-Holocene, land use has both diversified and increased exponentially, this has been associated with the arrival of new subsistence systems, crops, migrants and technologies, all giving rise to a sequence of significant phases of land-cover change. The first large-scale human influences began to occur around 4000?yr BP, associated with the introduction of domesticated livestock and the expansion of pastoral communities. The first widespread and intensive forest clearances were associated with the arrival of iron-using early farming communities around 2500?yr BP, particularly in productive and easily-cleared mid-altitudinal areas. Extensive and pervasive land-cover change has been associated with population growth, immigration and movement of people. The expansion of trading routes between the interior and the coast, starting around 1300?years ago and intensifying in the eighteenth and nineteenth centuries CE, was one such process. These caravan routes possibly acted as conduits for spreading New World crops such as maize (Zea mays), tobacco (Nicotiana spp.) and tomatoes (Solanum lycopersicum), although the processes and timings of their introductions remains poorly documented. The introduction of southeast Asian domesticates, especially banana (Musa spp.), rice (Oryza spp.), taro (Colocasia esculenta), and chicken (Gallus gallus), via transoceanic biological transfers around and across the Indian Ocean, from at least around 1300?yr BP, and potentially significantly earlier, also had profound social and ecological consequences across parts of the region.
Through an interdisciplinary synthesis of information and metadatasets, we explore the different drivers and directions of changes in land-cover, and the associated environmental histories and interactions with various cultures, technologies, and subsistence strategies through time and across space in East Africa. This review suggests topics for targeted future research that focus on areas and/or time periods where our understanding of the interactions between people, the environment and land-cover change are most contentious and/or poorly resolved. The review also offers a perspective on how knowledge of regional land-use change can be used to inform and provide perspectives on contemporary issues such as climate and ecosystem change models, conservation strategies, and the achievement of nature-based solutions for development purposes.
Padfield, R. et al. (2019). Co-producing a research agenda for sustainable palm oil. Frontiers [Online]. Available at: http://dx.doi.org/10.3389/ffgc.2019.00013.The rise of palm oil as the world’s most consumed vegetable oil has coincided with exponential growth in palm oil research
activity. Bibliometric analysis of research outputs reveals a distinct imbalance in the type of research being undertaken, notably a
disproportionate focus on biofuel and engineering topics. Recognising the expansion of oil palm agriculture across the tropics and
the increasing awareness of environmental, social and economic impacts, we seek to re-orient the existing research agenda
towards one that addresses the most fundamental and urgent questions defined by the palm oil stakeholder community. Following
consultation with 659 stakeholders from 38 countries, including palm oil growers, government agencies, non-governmental
organisations and researchers, the highest priority research questions were identified within 13 themes. The resulting 279
questions, including 26 ranked as top priority, reveal a diversity of environmental and social research challenges facing the
industry, ranging from the ecological and ecosystem impacts of production, to the livelihoods of plantation workers and smallholder
communities. Analysis of the knowledge type produced from these questions underscores a clear need for fundamental science
programmes, and studies that involve the consultation of non-academic stakeholders to develop ‘transformative’ solutions to the
oil palm sector. Stakeholders were most aligned in their choice of priority questions across the themes of policy and certification
related themes, and differed the most in environmental feedback, technology and smallholder related themes. Our
recommendations include improved regional academic leadership and coordination, greater engagement with private and public
stakeholders of Africa, and Central and South America, and enhanced collaborative efforts with researchers in the major
consuming countries of India and China.