Peer-reviewed publications

Increasing weather risks threaten agricultural production systems and food security across the world. Maintaining agricultural growth while minimizing climate shocks is crucial to building a resilient food production system and meeting developmental goals in vulnerable countries. Experts have proposed several technological, institutional, and policy interventions to help farmers adapt to current and future weather variability and to mitigate greenhouse gas (GHG) emissions. This paper presents the climate-smart village (CSV) approach as a means of performing agricultural research for development that robustly tests technological and institutional options for dealing with climatic variability and climate change in agriculture using participatory methods. It aims to scale up and scale out the appropriate options and draw out lessons for policy makers from local to global levels. The approach incorporates evaluation of climate-smart technologies, practices, services, and processes relevant to local climatic risk management and identifies opportunities for maximizing adaptation gains from synergies across different interventions and recognizing potential maladaptation and trade-offs. It ensures that these are aligned with local knowledge and link into development plans. This paper describes early results in Asia, Africa, and Latin America to illustrate different examples of the CSV approach in diverse agroecological settings. Results from initial studies indicate that the CSV approach has a high potential for scaling out promising climate-smart agricultural technologies, practices, and services. Climate analog studies indicate that the lessons learned at the CSV sites would be relevant to adaptation planning in a large part of global agricultural land even under scenarios of climate change. Key barriers and opportunities for further work are also discussed.

Sustainability challenges for nature and people are complex and interconnected, such that effective solutions require approaches and a common theory of change that bridge disparate disciplines and sectors. Causal chains offer promising approaches to achieving an integrated understanding of how actions affect ecosystems, the goods and services they provide, and ultimately, human well-being. Although causal chains and their variants are common tools across disciplines, their use remains highly inconsistent, limiting their ability to support and create a shared evidence base for joint actions. In this article, we present the foundational concepts and guidance of causal chains linking disciplines and sectors that do not often intersect to elucidate the effects of actions on ecosystems and society. We further discuss considerations for establishing and implementing causal chains, including nonlinearity, trade-offs and synergies, heterogeneity, scale, and confounding factors. Finally, we highlight the science, practice, and policy implications of causal chains to address real-world linked human–nature challenges.

A large body of research has explored opportunities to mitigate climate change in agricultural systems; however, less research has explored opportunities across the food system. Here we expand the existing research with a review of potential mitigation opportunities across the entire food system, including in pre-production, production, processing, transport, consumption and loss and waste. We detail and synthesize recent research on the topic, and explore the applicability of different climate mitigation strategies in varying country contexts with different economic and agricultural systems. Further, we highlight some potential adaptation co-benefits of food system mitigation strategies and explore the potential implications of such strategies on food systems as a whole. We suggest that a food systems research approach is greatly needed to capture such potential synergies, and highlight key areas of additional research including a greater focus on low- and middle-income countries in particular. We conclude by discussing the policy and finance opportunities needed to advance mitigation strategies in food systems.

Coastal ecosystems provide a number of life-sustaining services, from which benefits to humans can be derived. They are often inhabited by aquatic vegetation, such as mangroves, sea grasses and salt marshes. Given their wide geographic distribution and coverage, there is need to prioritize conservation efforts. An understanding of the human importance of these ecosystems can help with that prioritization. Here, we summarize a literature review of ecosystem service valuation studies. We discuss (1) the degree to which current valuation information is sufficient to prioritize blue carbon habitat conservation and restoration, (2) the relevancy of available studies, and (3) what is missing from the literature that would be needed to effectively prioritize conservation. Given the recent focus on blue carbon ecosystems in the international conservation, there are a number of areas where research on blue forest ecosystem assessment and valuation could be improved, from enhancing available methodologies to increasing valuation of rarely studied ecosystem services and wider geographic coverage of valuation studies. This review highlights these gaps and calls for a focus on broadening the ecosystem services that are valued, the methods used, and increasing valuation in underrepresented regions.

There is increasing interest in mining minerals on the seabed, including seafloor massive sulfide deposits that form at hydrothermal vents. The International Seabed Authority is currently drafting a Mining Code, including environmental regulations, for polymetallic sulfides and other mineral exploitation on the seabed in the area beyond national jurisdictions. This paper summarizes 1) the ecological vulnerability of active vent ecosystems and aspects of this vulnerability that remain subject to conjecture, 2) evidence for limited mineral resource opportunity at active vents, 3) non-extractive values of active vent ecosystems, 4) precedents and international obligations for protection of hydrothermal vents, and 5) obligations of the International Seabed Authority under the UN Convention on the Law of the Sea for protection of the marine environment from the impacts of mining. Heterogeneity of active vent ecosystems makes it extremely challenging to identify "representative" systems for any regional, area-based management approach to conservation. Protection of active vent ecosystems from mining impacts (direct and indirect) would set aside only a small fraction of the international seabed and its mineral resources, would contribute to international obligations for marine conservation, would have non-extractive benefits, and would be a precautionary approach.

Factors shaping coral-reef fish species assemblages can operate over a wide range of spatial scales (local versus regional) and across both proximate and evolutionary time. Niche theory and neutral theory provide frameworks for testing assumptions and generating insights about the importance of local versus regional processes. Niche theory postulates that species assemblages are an outcome of evolutionary processes at regional scales followed by local-scale interactions, whereas neutral theory presumes that species assemblages are formed by largely random processes drawing from regional species pools. Indo-Pacific cryptobenthic coral-reef fishes are highly evolved, ecologically diverse, temporally responsive, and situated on a natural longitudinal diversity gradient, making them an ideal group for testing predictions from niche and neutral theories and effects of regional and local processes on species assemblages. Using a combination of ecological metrics (fish density, diversity, assemblage composition) and evolutionary analyses (testing for phylogenetic niche conservatism), we demonstrate that the structure of cryptobenthic fish assemblages can be explained by a mixture of regional factors, such as the size of regional species pools and broad-scale barriers to gene flow/drivers of speciation, coupled with local-scale factors, such as the relative abundance of specific microhabitat types. Furthermore, species of cryptobenthic fishes have distinct microhabitat associations that drive significant differences in assemblage community structure between microhabitat types, and these distinct microhabitat associations are phylogenetically conserved over evolutionary timescales. The implied differential fitness of cryptobenthic fishes across varied microhabitats and the conserved nature of their ecology are consistent with predictions from niche theory. Neutral theory predictions may still hold true for early life-history stages, where stochastic factors may be more important in explaining recruitment. Overall, through integration of ecological and evolutionary techniques, and using multiple spatial scales, our study offers a unique perspective on factors determining coral-reef fish assemblages.

Coral reef ecosystems and the people who depend on them are increasingly exposed to the adverse effects of global environmental change (GEC), including increases in sea-surface temperature and ocean acidification. Managers and decision-makers need a better understanding of the options available for action in the face of these changes. We refine a typology of actions developed by Gattuso et al. (2015) that could serve in prioritizing strategies to deal with the impacts of GEC on reefs and people. Using the typology we refined, we investigate the scientific effort devoted to four types of management strategies: mitigate, protect, repair, adapt that we tie to the components of the chain of impact they affect: ecological vulnerability or social vulnerability. A systematic literature review is used to investigate quantitatively how scientific effort over the past 25 years is responding to the challenge posed by GEC on coral reefs and to identify gaps in research. A growing literature has focused on these impacts and on management strategies to sustain coral reef social-ecological systems. We identify 767 peer reviewed articles published between 1990 and 2016 that address coral reef management in the context of GEC. The rate of publication of such studies has increased over the years, following the general trend in climate research. The literature focuses on protect strategies the most, followed by mitigate and adapt strategies, and finally repair strategies. Developed countries, particularly Australia and the United States, are over-represented as authors and locations of case studies across all types of management strategies. Authors affiliated in developed countries play a major role in investigating case studies across the globe. The majority of articles focus on only one of the four categories of actions. A gap analysis reveals three directions for future research: (1) more research is needed in South-East Asia and other developing countries where the impacts of GEC on coral reefs will be the greatest, (2) more scholarly effort should be devoted to understanding how adapt and repair strategies can deal with the impacts of GEC, and (3) the simultaneous assessment of multiple strategies is needed to understand trade-offs and synergies between actions.

Riparian and floodplain corridors are particularly biodiverse and often form key habitat for animals in the terrestrial landscape and in most parts of the world they support more species of plants and animals than any other landscape unit. The maintenance and restoration of riparian and floodplain corridors is a conservation priority for both freshwater and terrestrial ecosystems with considerable benefits to be gained from restoring riparian and floodplain forests. These forests play key roles in providing organic matter that drives elements of the aquatic food chain, forming physical habitat, filtering out pollutants and providing shade for maintaining appropriate light environments and water temperatures. Floodplains provide habitat, food and recruitment opportunities for fishes and other fauna. A key question for managers restoring riparian corridors is ‘how wide is wide enough’? The minimal answer could be wide enough to enable full development of the vegetation canopy to maximize shade across the relevant water body and form an adequate mesic (moist, humid) micro-climate. A more informed answer is that the full width of the regularly inundated riparian and floodplain land should be restored. Systems of river corridor protected areas have been established in many jurisdictions around the world based on criteria such as biological importance, maintaining free-flowing ecological processes and supporting cultural values. Increasingly dams and levee banks are being removed from rivers and their floodplains to restore ecosystem functions and services. Restoration of functional riparian and floodplain systems may aid flood management and enhance other climate change adaptation measures.

Trophy hunting in Africa is currently under pressure as some countries explore various policies that aim to put a halt to an activity that many people in the Western developed world view as unpalatable or unethical. However, in the debate over trophy hunting policy the voices of local communities, who in many instances allow wildlife to persist on the lands they control because of the tangible benefits they derive from it, have been largely unheard. Here, we report on an opportunistic survey of 160 rural residents of Namibia from 32 communal conservancies that generate varying levels of livelihood benefits from wildlife uses, including trophy hunting. About three quarters of these community members were employed in some manner by the conservancy. We used a mixed methods approach to assess community members' perceptions on trophy hunting, the benefits it generates, whether it was "good" or "bad", and how they would respond if trophy hunting were halted. 91% stated they were not in favour of a ban on trophy hunting, and only 11% of respondents would support wildlife on communal lands if a ban were in fact enacted. Most respondents (90%) were happy with trophy hunting occurring on communal lands due to the benefits it provides. These responses were consistent across respondent demographic categories, although those who stand to lose the most (i.e., those employed by or managing a conservancy), viewed trophy hunting in an even more favourable light. Our results suggest that in Namibia, a trophy hunting ban would be viewed very poorly by conservancy residents, and would seriously weaken their support for wildlife conservation. The imposition of trophy hunting policies by countries far from where rural land managers are conserving wildlife would not only restrict communities' livelihood options, but may have perverse, negative impacts on wildlife conservation.

While corridors in conservation have a long history of use, evaluations of proposed or existing corridors in conservation landscapes are important to avoid the same fate as poorly-functioning "paper parks". We used resistance surface modeling and circuit theory to evaluate a number of corridors developed at regional and at local scales that aim to improve connectivity for large wildlife in the central part of the Kavango-Zambezi transfrontier conservation area. We used hourly GPS data from 16 collared African elephants (Loxodonta africana), and associated environmental data at used versus available movement paths, to develop a hierarchical Bayesian path selection function model. We used the resulting resistance surface across the study area as an input into circuit theory modeling to assess how well connectivity levels were captured by both types of corridors relative to several alternative scenarios. We found that the majority of regional-scale corridors performed relatively well at capturing elevated levels of connectivity relative to non-corridor comparisons, with 7 of 9 corridors rated as good or better in terms of how they captured electrical current levels (a proxy for connectivity). In contrast, only 14 of 33 smaller-scale, local corridors captured significantly higher levels of connectivity than adjacent non-corridor areas. Our results have practical implications for the design and implementation of wildlife connectivity conservation efforts in the world's largest transfrontier conservation landscape. Modern connectivity science approaches can help evaluate which proposed corridors are likely to function as intended, and which may need further refinement.