Freshwater fish diversity hotspots for conservation priorities in the Amazon Basin

Conserving freshwater habitats and their biodiversity in the Amazon Basin is a growing challenge in the face of rapid anthropogenic changes. We used the most comprehensive fish-occurrence database available (2355 valid species; 21,248 sampling points) and 3 ecological criteria (irreplaceability, representativeness, and vulnerability) to identify biodiversity hotspots based on 6 conservation templates (3 proactive, 1 reactive, 1 representative, and 1 balanced) to provide a set of alternative planning solutions for freshwater fish protection in the Amazon Basin. We identified empirically for each template the 17% of sub-basins that should be conserved and performed a prioritization analysis by identifying current and future (2050) threats (i.e., degree of deforestation and habitat fragmentation by dams). Two of our 3 proactive templates had around 65% of their surface covered by protected areas; high levels of irreplaceability (60% of endemics) and representativeness (71% of the Amazonian fish fauna); and low current and future vulnerability. These 2 templates, then, seemed more robust for conservation prioritization. The future of the selected sub-basins in these 2 proactive templates is not immediately threatened by human activities, and these sub-basins host the largest part of Amazonian biodiversity. They could easily be conserved if no additional threats occur between now and 2050.     

Adaptation to climate change and freshwater resources in Vusama village,Viti Levu,Fiji

Regional Environmental Change - Changing precipitation patterns including more intense and prolonged dry periods have become a growing concern for people living in the Pacific Island region. People...     

Measuring the effectiveness of landscape approaches to conservation and development

Landscape approaches attempt to achieve balance amongst multiple goals over long time periods and to adapt to changing conditions. We review project reports and the literature on integrated landscape approaches, and found a lack of documented studies of their long-term effectiveness. The combination of multiple and potentially changing goals presents problems for the conventional measures of impact. We propose more critical use of theories of change and measures of process and progress to complement the conventional impact assessments. Theories of change make the links between project deliverables, outputs, outcomes, and impacts explicit, and allow a full exploration of the landscape context. Landscape approaches are long-term engagements, but short-term process metrics are needed to confirm that progress is being made in negotiation of goals, meaningful stakeholder engagement, existence of connections to policy processes, and effectiveness of governance. Long-term impact metrics are needed to assess progress on achieving landscapes that deliver multiple societal benefits, including conservation, production, and livelihood benefits. Generic criteria for process are proposed, but impact metrics will be highly situation specific and must be derived from an effective process and a credible theory of change.     

Estimating carbon in savanna ecosystems: rational distribution of effort

Minimising the cost of repeatedly estimating C (C) stocks is crucial to the financial viability of projects that seek to sell C credits. Depending on the price of C, this may imply less or more sampling effort than would be applied for science objectives. In systems with heterogeneous C pools, such as savannas, this translates into a variable-effort sampling strategy that maximises the marginal additional C that can be claimed per incremental unit of effort expended. Analysis of a savanna in north-eastern South Africa indicates relatively modest returns per hectare due to the small C quantities and low sequestration rates. Under these conditions, areas in excess of 1,000 ha and infrequent sampling frequencies of 5–10 years are required to make such projects financially viable. For such projects the sample variance, number of samples, cost per sample and establishment costs have negligible impacts on financial viability. It was also found that the soil-C pool contributes up to three times the net returns of the aboveground C pool and provides a strong argument to monitor soil C for certification and market trading. The financial viability estimates, however, do not include the management or opportunity costs incurred in changing the land use. The economies of scale identified in this study combined with the massive area covered by savannas indicate that these additional costs can be covered. Further research is recommended to quantify these costs and interrogate the feasibility of large scale (in excess of 10,000 ha) C-sink projects in savanna systems.     

Genotoxicity is unrelated to total concentration of priority carcinogenic polycyclic aromatic hydrocarbons in soils undergoing biological treatment

A solid-phase microbiological assay was used to determine the changes in genotoxicity associated with sequestration or biodegradation of carcinogenic compounds in contaminated soils. The concentration of six carcinogenic polycyclic aromatic hydrocarbons (PAHs) did not change in 59 d in sterile soil, but the genotoxicity declined markedly. In a soil undergoing bioremediation in the field for 147 d or biodegradation in the laboratory for 180 d, the concentrations either changed little or declined at different rates, but the genotoxicity increased followed by a decline. The genotoxicity of a second soil declined as a result of biological treatment. The data show that genotoxicity of contaminated soils may be unrelated to the concentration of carcinogenic PAHs because of aging or new mutagens formed during biological treatment.     

Effect of monosodium methanarsonate application on cuticle wax content of cocklebur and cotton plants

Leaf cuticle waxes were extracted from monosodium methanearsonate (MSMA)-resistant (R) and -susceptible (S) common cocklebur (Xanthium strumarium L.) and cotton (Gossypium hirsutum L.) plants at 0, 3, 5, and 7 days after treatment (DAT) following 1x and 2x MSMA applications. Wax constituents were analyzed by gas chromatography (GC) with flame ionization detection and compared to alkane and alcohol standards of carbon lengths varying from C21 to C30. Differences in waxes were calculated and reported as change per ng mm2-1. Tricosane (C23) was found to increase following MSMA applications. All other alkanes decreased by 7 DAT, with some showing a linear effect over time in the R-cocklebur. Alcohol constituents were also observed to decrease by 7 DAT. Total arsenic in the extracted wax fraction was determined, with greatest quantities detected in the R-cocklebur. Wax changes are not believed to play a role in cotton tolerance, since changes in cuticle concentrations were minimal. Cocklebur resistance to MSMA is not due to cuticle constituents; the wax changes are a secondary effect in response to herbicide application.     

Benefits of protected areas for nonbreeding waterbirds adjusting their distributions under climate warming

Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993–2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTI_SD). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTI_SD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTI_SD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming.