Early succession arthropod community changes on experimental passion fruit plant patches along a land-use gradient in Ecuador

Many tropical landscapes are today characterized by small forest patches embedded in an agricultural mosaic matrix. In such highly fragmented landscapes, agroforests have already been recognized as refuges for biodiversity but few studies have investigated the potential of non-forested land-use types to contribute to overall biodiversity of functionally important taxa in the tropics. This study experimentally investigated species richness, abundance, and community similarity of arthropods on Yellow Passion fruit plants, planted in standardized patches in 30 sites along a land-use intensity gradient. The gradient comprised all major land-use types of the area: forest fragments, abandoned coffee agroforests, coffee agroforests managed under shade trees, pastures, and rice fields in Coastal Ecuador. We found a total of 2123 individuals belonging to 242 species. Overall arthropod species richness increased with light intensity and leaf-surface area and decreased with land-use intensity: forest fragments and abandoned coffee agroforests harboured significantly more species than rice or pastures. Overall diversity in managed coffee agroforests was intermediate between the intensively managed and more natural habitats. However, the three most abundant taxa of arthropods (ants, spiders, and beetles) had the highest number of species in managed coffee agroforests, while ant abundance was highest in abandoned coffee agroforests and spider abundance highest in managed coffee agroforests. Analyses of community similarity revealed that open (pasture, and rice) and shaded (forest, abandoned and managed coffee agroforests) land-use types had distinct arthropod communities. In conclusion, although open agricultural land-use types tend to have fewer species in lower numbers, all land-use types contribute to overall biodiversity of the agricultural matrix because of distinct communities in shaded vs. non-shaded land-use types.     

Climate change and mining in Canada

Climate is an important component of the operating environment for the Canadian mining sector. However, in recent years mines across Canada have been affected by significant climatic hazards, several which are regarded to be symptomatic of climate change. For the mining sector, climate change is a pressing environmental threat and a significant business risk. The extent to which the mining sector is able to mitigate its own impact and adapt to climate change will affect its long-term success and prosperity, and have profound economic consequences for host communities. This paper draws upon case studies conducted with mining operations in Canada involving in-depth interviews with mining professionals and analysis of secondary sources to characterize the vulnerability of the Canadian mining industry to climate change. Five key findings are discussed: i) mines in the case studies are affected by climate events that are indicative of climate change, with examples of negative impacts over the past decade; ii) most mine infrastructure has been designed assuming that the climate is not changing; iii) most industry stakeholders interviewed view climate change as a minor concern; iv) limited adaption planning for future climate change is underway; v) significant vulnerabilities exist in the post-operational phase of mines. This paper argues for greater collaboration among mining companies, regulators, scientists and other industry stakeholders to develop practical adaptation strategies that can be integrated into existing and new mine operations, including in the post-operational phase.     

Policy guidance for identifying and effectively managing perpetual environmental impacts from new hardrock mines

Perpetual environmental management at operating and proposed hardrock mines is a rapidly expanding global dilemma. While economies of scale have encouraged larger mines, improved models routinely predict long-term water quality degradation at sulfide metal mines. Technical causes include oxidation of sulfide minerals and seepage from waste rock, tailings, and pit wall rock. Perpetual treatment is usually less expensive than permanent stabilization, even using 2% “risk-free” investment return rate; but this option greatly increases the social and financial complexity. A few regulations address perpetual management, but specific requirements range from formal acceptance to complete prohibition. With vague regulations, predictions of long-term impacts often delay permitting as operators and regulators grapple with model uncertainty and regulatory ambiguity. Risk management tools (e.g., insurance, inflation-protected investments, etc.) can reduce but cannot eliminate risk, and their continued availability is uncertain. What regulators and mine operators need – but do not have – is a clear framework to guide them in developing perpetual management plans that balance risks (e.g., uncertainty in predictions, cost, finance, and governance) and ensure responsible environmental and social stewardship. This paper responds with a review of perpetual mine management issues, including technical causes, policy examples, investment tools, case studies, technical remedies, and principles for successful long-term management.     

Improving arsenopyrite oxidation rate laws: implications for arsenic mobilization during aquifer storage and recovery (ASR)

Aquifer storage and recovery (ASR) and aquifer recharge (AR) provide technical solutions to address water supply deficits and growing future water demands. Unfortunately, the mobilization of naturally present arsenic due to ASR/AR operations has undermined its application on a larger scale. Predicting arsenic mobility in the subsurface during ASR/AR is further complicated by site-specific factors, including the arsenic mobilization mechanisms, groundwater flow conditions, and multi-phase geochemical interactions. In order to ensure safe and sustainable ASR/AR operation, a better understanding of these factors is needed. The current study thus aims to better characterize and model arsenic remobilization at ASR/AR sites by compiling and analyzing available kinetic data on arsenic mobilization from arsenopyrite under different aqueous conditions. More robust and widely applicable rate laws are developed for geochemical conditions relevant to ASR/AR. Sensitivity analysis of these new rate laws gives further insight into the controlling geochemical factors for arsenic mobilization. When improved rate laws are incorporated as the inputs for reactive transport modeling, arsenic mobilization in ASR/AR operations can be predicted with an improved accuracy. The outcomes will be used to guide groundwater monitoring and specify ASR/AR operational parameters, including water pretreatment requirements prior to injection.     

Population structure of <Emphasis Type="Italic">Symbiodinium</Emphasis> sp. associated with the common sea fan, <Emphasis Type="Italic">Gorgonia ventalina</Emphasis>, in the Florida Keys across distance,depth, and time

Numerous marine invertebrates form endosymbiotic relationships with dinoflagellates in the genus Symbiodinium. However, few studies have examined the fine-scale population structure of these symbionts. Here, we describe the genetic structure of Symbiodinium type “B1/B184” inhabiting the gorgonian Gorgonia ventalina along the Florida Keys. Six polymorphic microsatellite loci were utilized to examine 16 populations along the Upper, Middle, and Lower Keys spanning a range of ~200 km. Multiple statistical tests detected significant differentiation in 54–92% of the 120 possible pairwise comparisons between localities, suggesting low levels of gene flow in these dinoflagellates. In general, populations clustered by geographic region and/or reefs in close proximity. Some of the sharpest population differentiation was detected between Symbiodinium from deep and shallow sites on the same reef. In spite of the high degree of population structure, alleles and genotypes were shared among localities, indicating some connectivity between Symbiodinium populations associated with G. ventalina. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Developing a circumpolar programme for the monitoring of Arctic terrestrial biodiversity

The Arctic is undergoing biological and environmental changes, and a coordinated effort to monitor is critical to detect these changes. The Circumpolar Biodiversity Monitoring Programme (CBMP) of the Arctic Council biodiversity working group, Conservation of Arctic Flora and Fauna (CAFF), has developed pan-Arctic biodiversity monitoring plans that aims to improve the ability to detect and report on long-term changes. Whilst introducing this special issue, this paper also presents the making of the terrestrial monitoring plan and discusses how the plan follows the steps required for an adaptive and ecosystem-based monitoring programme. In this article, we discuss how data on key findings can be used to inform circumpolar and global assessments, including the State of the Arctic Terrestrial Biodiversity Report, which will be the first terrestrial assessment made by the CBMP. Key findings, advice for future monitoring and lessons learned will be used in planning next steps of pan-Arctic coordinated monitoring.     

Are soils beneath coniferous tree stands more acidic than soils beneath deciduous tree stands?

Environmental Science and Pollution Research - In 2008, the Mulberry River, a National Wild and Scenic River, was listed as impaired due to low pH (below pH&nbsp;6.0). Over the last...     

An approach to determining functional parameters of microperiphyton fauna in colonization surveys for marine bioassessment based on rarefaction curves

The functional parameters, i.e., the estimated equilibrium species number (S _eq ), the colonization rate constant, and the time taken to reach 90 % of S _eq (T ₉₀ ), of microperiphyton fauna have been widely used to determine the water quality status in aquatic ecosystems. The objective of this investigation was to develop a protocol for determining functional parameters of microperiphyton fauna in colonization surveys for marine bioassessment based on rarefaction and regression analyses. The temporal dynamics in species richness of microperiphyton fauna during the colonization period was analyzed based on a dataset of periphytic ciliates in Chinese coastal waters of the Yellow Sea. The results showed that (1) based on observed species richness and estimated maximum species numbers, a total of 16 glass slides were required in order to achieve coefficients of variation of <5 % in the functional parameters; (2) the rarefied average species richness and functional parameters showed weak sensitivity to sampling effort; (3) the temporal variations in average species richness were well-fitted to the MacArthur-Wilson model; and (4) the sampling effort of ~8 glass slides was sufficient to achieve coefficients of variation of <5 % in equilibrium average species number (AvS _eq ), colonization rate (AvG), and the time to reach 90 % of AvS _eq (AvT ₉₀ ) based on the average species richness. The findings suggest that the AvS _eq , AvG, and AvT ₉₀ values based on rarefied average species richness of microperiphyton might be used as reliable ecological indicators for the bioassessment of marine water quality in coastal habitats.     

Small farm ponds: overlooked features with important impacts on watershed sediment transport

Despite their size, small farm ponds are important features in many landscapes. Yet hydrographical databases often fail to capture these ponds, and their impacts on watershed processes remain unclear. For a 230‐km² portion of central Texas, United States (U.S.), we created a historical inventory of ponds and quantified the accuracy of automated detection methods under varying drought conditions. In addition, we documented pond dredging/enlargement events and identified sites that had been abandoned. We also analyzed sediment cores from downstream reservoirs to track changes in watershed sediment transport. Over 75 years, pond densities increased more than 350% — to among the highest documented in the U.S. — and the ability of automated methods to detect these ponds was highly dependent on drought severity (R² = 0.96). Approximately 5% of ponds present in the 1950s were no longer present in 2012, while 33% were dredged between 1937 and 2012. Downstream reservoir sedimentation has decreased by an average of 55% as ponds have increased in number. These findings suggest that small ponds and the maintenance of trapping efficiency have large‐scale impacts on sediment dynamics. Accurately accounting for these storage effects is vital to water resource planning efforts.