Peer-reviewed publications

Policies aimed at reducing deforestation in the Amazon basin, such as ARPA and a robustly enforced Forest Code, could have a substantial influence on the basin’s future hydropower production potential, land-use based carbon emissions, and gross economic product. We use regional models to estimate the impact that high levels of forest conservation will have on the Basin’s provision of these ecosystem services and its overall economic performance as of 2050 relative to the Basin’s delivery of these services and economic performance from a much more developed 2050 landscape. We identify three major lessons learned from our research. First, the hydropower benefits of forest conservation policies, including protected areas, are distributed unevenly across the Amazon basin due to atmospheric feedbacks. Second, these policies also have a substantial influence on regional and global carbon emissions. Finally, policymakers need to be cognizant of the substantial economic opportunity costs that conservation policies can create and how the spatial mismatch of policy costs and benefits can lead to policy failure. For example, we find that the loss in basin gross product in 2050 due to more stringent forest conservation is likely to be greater than combined value of more hydropower potential and more carbon sequestration in 2050 due to more stringent forest conservation. For Brazilians specifically the calculus is even a bit worse as carbon sequestration is a global good that accrues to most people outside of Brazil. Of course our analysis is missing the many other valuable ecosystem services than are enhanced by conservation. We would need to add these additional ecosystem service values to our cost-benefit ledger before we could begin to ascribe the full conservation-economic tradeoffs to more stringent forest conservation.

Delivering access to sufficient food, energy and water resources to ensure human wellbeing is a major concern for governments worldwide. However, it is crucial to account for the ‘nexus’ of interactions between these natural resources and the consequent implications for human wellbeing. The private sector has a critical role in driving positive change towards more sustainable nexus management and could reap considerable benefits from collaboration with researchers to devise solutions to some of the foremost sustainability challenges of today. Yet opportunities are missed because the private sector is rarely involved in the formulation of deliverable research priorities. We convened senior research scientists and influential business leaders to collaboratively identify the top forty questions that, if answered, would best help companies understand and manage their food-energy-water-environment nexus dependencies and impacts. Codification of the top order nexus themes highlighted research priorities around development of pragmatic yet credible tools that allow businesses to incorporate nexus interactions into their decision-making; demonstration of the business case for more sustainable nexus management; identification of the most effective levers for behaviour change; and understanding incentives or circumstances that allow individuals and businesses to take a leadership stance. Greater investment in the complex but productive relations between the private sector and research community will create deeper and more meaningful collaboration and cooperation.

The Nile crocodile, Crocodylus niloticus, is found throughout sub-Saharan Africa, including Namibia, Botswana and Angola. The species was transferred from CITES Appendix I to Appendix II in 2004, although it is recognized as peripherally endangered in Namibia due to diminishing habitat availability primarily from human encroachment. In 2013, a species management plan was approved in Namibia to assess the management of the Namibian Nile crocodile populations. During 2012, an aerial survey was conducted to provide an estimate of Nile crocodile population numbers. A recently developed N-mixture model for estimation of abundance and spatial variation was used. Detection probability correlated to animal size and environmental covariates. Our data also suggest that small crocodiles are easier to detect during the spring. The abundance for different size classes was influenced by river complexity (vegetation, depth, channels) and the distribution of human settlements. An estimated 806 individuals were counted along the 352 km Namibian portion of the Kunene River system with a conservative estimate of 562 crocodiles regardless of size. The parameter estimates generated by the analysis suggested that the class-structured model can produce reliable estimates of total abundance and of local abundance for this section in the Kunene River system.

table {mso-displayed-decimal-separator:"\."; mso-displayed-thousand-separator:"\,";} tr Marine protected areas (MPAs) have historically been implemented and managed in a top-down way, excluding resource-dependent users from planning and management. In response to conflict and non-compliance, the governance of marine resources is increasingly embracing community-based approaches, assuming that by putting communities at the forefront of planning and management, participation will increase, causing positive social and ecological impacts. Given the relative newness of community-based MPAs, this study explores how resource users perceive their impacts on ecosystem services (ES) and human well-being (HWB). This study explores two community-based MPAs called tengefus in Kenya using mixed qualitative methods, including a participatory photography method called photovoice. Participation in and donor support for tengefus influences how resource users perceived tengefus and their impacts on ES and HWB. Individuals who were engaged in the tengefu from the inception or held official positions perceived more positive impacts on ES and HWB compared to those not as involved. Tengefus were often viewed by communities as attractors for external support and funding, positively influencing attitudes and feelings towards conservation. One site, the first tengefu in Kenya, had more external support and was surrounded by positive perceptions, while the other site had little external support and was surrounded by more conflict and mixed perceptions. This study exemplifies the complex social-political dynamics that MPAs create and are embedded within. Community-based MPA initiatives could benefit from ensuring widespread engagement throughout the inception, implementation and management, recognizing and managing expectations around donor support, and not assuming that benefits spillover throughout the community.

Protected areas are a cornerstone strategy for terrestrial and increasingly marine biodiversity conservation, but their use for conserving inland waters has received comparatively scant attention. In 2010, the Convention on Biological Diversity (CBD) included a target of 17% protection for inland waters, yet there has been no meaningful way of measuring progress toward that target. Defining and evaluating ‘protection’ is especially complicated for rivers because their integrity is intimately linked to impacts in their upstream catchments. A new generation of global hydrographic data now enables a high-resolution, standardized assessment of how upland activities may be propagated downstream. Here we develop and apply, globally, a river protection metric that integrates both local and upstream catchment protection. We found that ‘integrated’ river protection is highly variable across geographies and river size classes and in most basins falls short of the 17% CBD target. Around the world about 70% of river reaches (by length) have no protected areas in their upstream catchments, and only 11.1% (by length) achieve full integrated protection. The average level of integrated protection is 13.5% globally, yet the majority of the world's largest basins show averages below 10%. Within basins, gaps are particularly severe for larger rivers.

Several competing human behavior models have been proposed to model boundedly rational adversaries in repeated Stackelberg Security Games (SSG). However, these existing models fail to address three main issues which are detrimental to defender performance. First, while they attempt to learn adversary behavior models from adversaries' past actions (“attacks on targets”), they fail to take into account adversaries' future adaptation based on successes or failures of these past actions. Second, existing algorithms fail to learn a reliable model of the adversary unless there exists sufficient data collected by exposing enough of the attack surface – a situation that often arises in initial rounds of the repeated SSG. Third, current leading models have failed to include probability weighting functions, even though it is well known that human beings' weighting of probability is typically nonlinear.To address these limitations of existing models, this article provides three main contributions. Our first contribution is a new human behavior model, SHARP, which mitigates these three limitations as follows: (i) SHARP reasons based on success or failure of the adversary's past actions on exposed portions of the attack surface to model adversary adaptivity; (ii) SHARP reasons about similarity between exposed and unexposed areas of the attack surface, and also incorporates a discounting parameter to mitigate adversary's lack of exposure to enough of the attack surface; and (iii) SHARP integrates a non-linear probability weighting function to capture the adversary's true weighting of probability. Our second contribution is a first “repeated measures study” – at least in the context of SSGs – of competing human behavior models. This study, where each experiment lasted a period of multiple weeks with individual sets of human subjects on the Amazon Mechanical Turk platform, illustrates the strengths and weaknesses of different models and shows the advantages of SHARP. Our third major contribution is to demonstrate SHARP's superiority by conducting real-world human subjects experiments at the Bukit Barisan Seletan National Park in Indonesia against wildlife security experts.

The ability of existing protected areas (PAs) to conserve freshwater species and ecosystems has been little investigated. In this study the freshwater conservation potential of PAs was evaluated based on their geospatial attributes and spatial relationship to threats. Specifically, the following questions were addressed: (a) to what extent, if any, do PA drainage network location and size affect the potential of PAs to conserve freshwater species and habitats within them?; (b) how are the factors that limit or promote conservation potential distributed in relation to PAs across a region?; and (c) what are the broader implications for how PAs can be designed and managed to contribute to freshwater conservation around the world? Eight factors that affect freshwater conservation potential for 297 PAs within the Tennessee and Cumberland River Basins (US) were analysed. Four of these attributes (connectivity, impervious surface area, agricultural land cover, and upstream storage) showed enough variation across PAs such that the effect of PA size, drainage network position, and their interaction on those attributes, was able to be modelled. The results support the hypothesis that PA drainage network location and size affect freshwater conservation potential of PAs. Both have a statistically significant effect on each of the four conservation potential attributes, either as a main effect, or through an interaction, although the direction of these relationships is not always intuitive. Of the factors that limit or promote conservation potential, PAs appear to be most often affected by land conversion to agriculture and a loss of connectivity. This study underscores the importance of PA managers understanding key internal and external threats so that they can take mitigating or minimizing action, and the need to define PA locations and boundaries within a larger basin context.

The Strategic Plan for Biodiversity (2011–2020), adopted at the 10th meeting of the Conference of the Parties to the Convention on Biological Diversity, sets 20 Aichi Biodiversity Targets to be met by 2020 to address biodiversity loss and ensure its sustainable and equitable use. Aichi Biodiversity Target 11 describes what an improved conservation network would look like for marine, terrestrial and inland water areas, including freshwater ecosystems. To date, there is no comprehensive assessment of what needs to be achieved to meet Target 11 for freshwater biodiversity. Reports on implementation often fail to consider explicitly freshwater ecosystem processes and habitats, the pressures upon them, and therefore the full range of requirements and actions needed to sustain them. Here the current progress and key gaps for meeting Aichi Target 11 are assessed by exploring the implications of each of its clauses for freshwater biodiversity. Concerted action on Aichi Biodiversity Target 11 for freshwater biodiversity by 2020 is required in a number of areas: a robust baseline is needed for each of the clauses described here at national and global scales; designation of new protected areas or expansion of existing protected areas to cover known areas of importance for biodiversity and ecosystem services, and a representative sample of biodiversity; use of Other Effective Area-Based Conservation Measures (OECMs) in places where designating a protected area is not appropriate; and promoting and implementing better management strategies for fresh water in protected areas that consider its inherent connectivity, contextual vulnerability, and required human and technical capacity. Considering the specific requirements of freshwater systems through Aichi Biodiversity Target 11 has long-term value to the Sustainable Development Goals discussions and global conservation policy agenda into the coming decades.

Background:
Recent studies have shown that fragmentation is an increasing threat to global forests, which has major impacts on biodiversity and the important ecosystem services provided by forested landscapes. Several tools have been developed to evaluate global patterns of fragmentation, which have potential applications for REDD+. We study how canopy height and above ground biomass (AGB) change across several categories of forest edges determined by fragmentation analysis. We use Democratic Republic of Congo (DRC) as an example.

Results
An analysis of variance of different edge widths and airborne estimated canopy height found that canopy heights were significantly different in forest edges at a distance of 100 m from the nonforest edge. Biomass was significantly different between fragmentation classes at an edge distance of 300 m. Core forest types were found to have significantly higher canopy height and greater AGB than forest edges and patches, where height and biomass decrease significantly as the level of fragmentation increases. A change analysis shows that deforestation and degradation are increasing over time and biomass loss associated with degradation account for at least one quarter of total loss. We estimate that about 80 % of primary forests are intact, which decreases 3.5 % over the 15 year study period, as primary forest is either deforested or transitioned to forest edge. While the carbon loss per hectare is lower than that of deforestation, degradation potentially affects up to three times more area than deforestation alone.

Conclusions
When defining forest degradation by decreased biomass without any loss in forest area, assessing transitions of core forest to edges over time can contribute an important element to REDD+MRV systems. The estimation of changes between different forest fragmentation types and their associated biomass loss can provide an estimate of degradation carbon emission factors. Forest degradation and emissions due to fragmentation are often underestimated and should comprise an essential component of MRV systems.

Mangroves are critical in the ecological, economic and social development of coastal rural and urban communities. However, they are under threat by climate change and anthropogenic activities. The Sunda Banda Seascape (SBS), Indonesia, is among the world’s richest regions of mangrove biomass and biodiversity. To inform current and future management strategies, it is critical to provide estimates of how mangroves will respond to climate change in this region. Therefore, this paper utilized spatial analysis with model-based climatic indicators (temperature and precipitation) and mangrove distribution maps to estimate a benchmark for the mangrove biomass of the SBS in six scenarios, namely the Last Inter-glacial Period, the current scenario (1950–2000) and all four projected Representative Concentration Pathways in 2070 due to climate change. Despite mangroves gaining more biomass with climate change (the increase in CO2 concentration), this paper highlighted the great proportion of below-ground biomass in mangrove forests. It also showed that the changes in spatial distribution of mangrove biomass became more variable in the context of climate change. As mangroves have been proposed as an essential component of climate change strategies, this study can serve as a baseline for future studies and resource management strategies.