Mercury in aquatic ecosystems of two indigenous communities in the Piedmont Ecuadorian Amazon: evidence from fish, water, and sediments.

Mercury is a highly toxic element present in water, soil, air, and biota. Anthropogenic activities, such as burning fossil fuels, mining, and deforestation, contribute to the presence and mobilization of mercury between environmental compartments. Although current research on mercury pathways has advanced our understanding of the risks associated with human exposure, limited information exists for remote areas with high diversity of fauna, flora, and indigenous communities. This study aims to deepen our understanding of the presence of total mercury in water, sediments, and fish, within aquatic ecosystems of two indigenous territories: Gomataon (Waorani Nationality) and Sinangoé (Ai´Cofán Nationality) in the Ecuadorian Amazon. Our findings indicate that, for most fish (91.5%), sediment (100%) and water (95.3%) samples, mercury levels fall under international limits. For fish, no significant differences in mercury levels were detected between the two communities. However, eight species exceeded recommended global limits, and one surpassed the threshold according to Ecuadorian legislation. Piscivore and omnivore fish exhibited the highest concentrations of total mercury among trophic guilds. Only one water sample from each community's territory exceeded these limits. Total mercury in sediments exhibited greater concentrations in Gomataon than Sinangoé. Greater levels of mercury in sediments were associated with the occurrence of total organic carbon. Considering that members of the communities consume the analyzed fish, an interdisciplinary approach, including isotopic analysis, methylmercury sampling in humans, and mercury monitoring over time, is imperative for a detailed risk assessment of mercury exposure in Amazonian communities.

The global challenge of reducing mercury contamination from artisanal and small-scale gold mining (ASGM): evaluating solutions using generic theories of change.

Mercury contamination from artisanal and small-scale gold mining (ASGM) currently accounts for 37% of the global total, often affecting tropical regions where regulations, if they exist, are often poorly enforced. Ingestion by people and other animals damages the nervous, reproductive, and cognitive systems. Despite the efforts of many organizations and governments to curb mercury releases from ASGM, it is increasing globally. There are many possible interventions, all with significant complexity and cost. Therefore, we recommend taking an established systematic approach to articulate the current situation and construct theories of change (ToC) for different possible interventions for any government or organization trying to solve this problem. Here we present a high-level situation analysis and generic ToC to support a more coordinated approach that explicitly builds upon previous experience to identify organization- and situation-appropriate engagement on this issue. We then illustrate the use of these generic models to construct a specific ToC with a policy-focused entry point. This includes interventions through (1) engagement with the global Minamata Convention on Mercury; (2) support for existing national laws and policies connected to ASGM and mercury contamination; and (3) engagement of indigenous people and local communities with governments to meet the governments' legal obligations. By methodically articulating assumptions about interventions, connections among actions, and desired outcomes, it is possible to create a more effective approach that will encourage more coordination and cooperation among governments and other practitioners to maximize their investments and support broad environmental and socio-political outcomes necessary to address this pernicious problem.

How effective is community-based management of freshwater resources? A review.

Despite the existence of numerous research studies on community-based conservation, relatively few focus on the particularities of freshwater ecosystems. Freshwater ecosystems are distinct from terrestrial and marine ecosystems, exhibiting both greater concentrations of biodiversity and elevated threats. In addition, freshwater resources have distinct social, legal, political, and economic characteristics which limit the generalizability of community-based conservation research from other ecological domains. We examine peer-reviewed literature on community-based management of freshwater resources to understand and assess project contexts and outcomes. Our review indicates that studies of freshwater community-based management are limited in number and representativeness. While positive outcomes for both biodiversity and human well-being are commonly reported, limitations due to study design constrain the ability to infer the significance or causality of these effects. Overall, our analysis indicates that there are several gaps in the available research: across geographic regions, freshwater ecosystem types, intervention types, and environmental and human well-being outcome types. Given the importance of freshwater resources to Indigenous Peoples and local communities, our review highlights the critical need to generate evidence across more diverse contexts to achieve greater clarity on whether and how community-based projects can be most effective.

Spatial planning for a green economy: National-level hydrologic ecosystem services priority areas for Gabon.

Rapidly developing countries contain both the bulk of intact natural areas and biodiversity, and the greatest untapped natural resource stocks, placing them at the forefront of "green" economic development opportunities. However, most lack scientific tools to create development plans that account for biodiversity and ecosystem services, diminishing the real potential to be sustainable. Existing methods focus on biodiversity and carbon priority areas across large geographies (e.g., countries, states/provinces), leaving out essential services associated with water supplies, among others. These hydrologic ecosystem services (HES) are especially absent from methods applied at large geographies and in data-limited contexts. Here, we present a novel, spatially explicit, and relatively simple methodology to identify countrywide HES priority areas. We applied our methodology to the Gabonese Republic, a country undergoing a major economic transformation under a governmental commitment to balance conservation and development goals. We present the first national-scale maps of HES priority areas across Gabon for erosion control, nutrient retention, and groundwater recharge. Priority sub-watersheds covered 44% of the country's extent. Only 3% of the country was identified as a priority area for all HES simultaneously, highlighting the need to conserve different areas for each different hydrologic service. While spatial tradeoffs occur amongst HES, we identified synergies with two other conservation values, given that 66% of HES priority areas intersect regions of above average area-weighted (by sub-watersheds) total forest carbon stocks and 38% intersect with terrestrial national parks. Considering implications for development, we identified HES priority areas overlapping current or proposed major roads, forestry concessions, and active mining concessions, highlighting the need for proactive planning for avoidance areas and compensatory offsets to mitigate potential conflicts. Collectively, our results provide insight into strategies to protect HES as part of Gabon's development strategy, while providing a replicable methodology for application to new scales, geographies, and policy contexts.

Nitrogen translocation in Sphagnum mosses: effects of atmospheric nitrogen deposition.

• Here, the hypothesis was tested that nitrogen (N) translocation from older to younger parts of Sphagnum decreases as N inputs from atmospheric deposition increase. • Nitrogen translocation in Sphagnum mosses was compared in bogs with contrasting atmospheric N deposition (Adirondack - relatively high N deposition; Maine - relatively low) and by following the movement of a 15 NH4 15 NO3 tracer applied to plots of Sphagnum capillifolium over 2 yr. • Annual N translocation ranged from 11% to > 80% in the lower and higher influx sites, respectively. Nitrogen translocation was an important process for the N budget of the Sphagnum mosses, contributing 0.5-11% of the annual N requirements. These results suggest that N translocation is as important as direct N retention from atmospheric deposition for the N budget of the mosses. Contrary to expectations, N translocation was greater in the high (Adirondack) than in the low (Maine) deposition sites. • If N translocation is closely tied to water availability, the relative positions of the water tables in the sites over the course of the experiments might account for differences in N translocation among sites. The lower translocation (Maine) sites had lower water tables in the first year of the experiment and experienced a more severe drought in the second year than did the Adirondack sites.