Abundance declines of a native forb have nonlinear impacts on grassland invasion resistance

The effects of declining plant biodiversity on ecosystem processes are well studied, with most investigations examining the role of species richness declines rather than declines of species abundance. Using grassland mesocosms, we examined how the abundance of a native, resident species, Hemizonia congesta (hayfield tarweed), affected exotic Centaurea solstitialis (yellow starthistle) invasion. We found that progressive H. congesta abundance declines had threshold effects on invasion resistance, with initial declines resulting in minor increases in invasion and subsequent declines leading to accelerating increases in invader performance. Reduced invasion resistance was explained by increased resource availability as H. congesta declined. We also found evidence that resident abundance might indirectly affect invasion by mediating invader impact on resident competitors; C. solstitialis disproportionately reduced H. congesta biomass in low-abundance rather than high-abundance populations. H. congesta's direct and indirect effects on invasion resistance illustrate that an individual species' declining abundance can have accelerating, deleterious effects on ecosystem functions of conservation value.     

Field methods and example applications for the Min-Trap® mineral sampler

Important reactive minerals are commonly created during in situ groundwater remediation activities; for example, iron sulfides formed during enhanced reduction approaches can abiotically degrade many chlorinated solvents. However, cost-effective tools to evaluate these treatment processes in field applications are limited and the collection of samples to evaluate in situ mineral formation is costly due to drilling requirements. The new passive Min-Trap sampler is a simple and cost-effective tool that can directly measure the formation of reactive minerals in situ without the need for additional drilling or soil core collection. The methods presented here describe how Min-Traps deployed in conventional monitoring wells can measure reactive minerals and how these minerals can be identified through commercially available analytical methods. Several examples are presented that show how Min-Traps can be used to characterize the rate and spatial variability of reactive mineral precipitation and these data may support operation and optimization decisions.     

Influence of the residence time of street trees and their soils on trace element contamination in Paris (France)

Environmental Science and Pollution Research - With the actual increasing interest for urban soils, the evaluation of soil contamination by trace elements and the dynamics of this contamination...     

The Adaptation for Conservation Targets (ACT) Framework: A Tool for Incorporating Climate Change into Natural Resource Management

As natural resource management agencies and conservation organizations seek guidance on responding to climate change, myriad potential actions and strategies have been proposed for increasing the long-term viability of some attributes of natural systems. Managers need practical tools for selecting among these actions and strategies to develop a tailored management approach for specific targets at a given location. We developed and present one such tool, the participatory Adaptation for Conservation Targets (ACT) framework, which considers the effects of climate change in the development of management actions for particular species, ecosystems and ecological functions. Our framework is based on the premise that effective adaptation of management to climate change can rely on local knowledge of an ecosystem and does not necessarily require detailed projections of climate change or its effects. We illustrate the ACT framework by applying it to an ecological function in the Greater Yellowstone Ecosystem (Montana, Wyoming, and Idaho, USA)-water flows in the upper Yellowstone River. We suggest that the ACT framework is a practical tool for initiating adaptation planning, and for generating and communicating specific management interventions given an increasingly altered, yet uncertain, climate.     

Estimates of critical acid loads and exceedances for forest soils across the conterminous United States

Concern regarding the impacts of continued nitrogen and sulfur deposition on ecosystem health has prompted the development of critical acid load assessments for forest soils. A critical acid load is a quantitative estimate of exposure to one or more pollutants at or above which harmful acidification-related effects on sensitive elements of the environment occur. A pollutant load in excess of a critical acid load is termed exceedance. This study combined a simple mass balance equation with national-scale databases to estimate critical acid load and exceedance for forest soils at a 1-km(2) spatial resolution across the conterminous US. This study estimated that about 15% of US forest soils are in exceedance of their critical acid load by more than 250eqha(-1)yr(-1), including much of New England and West Virginia. Very few areas of exceedance were predicted in the western US.     

Impacts of Multiple Stresses on Water Demand and Supply Across the Southeastern United States1

Abstract: Assessment of long‐term impacts of projected changes in climate, population, and land use and land cover on regional water resource is critical to the sustainable development of the southeastern United States. The objective of this study was to fully budget annual water availability for water supply (precipitation ? evapotranspiration + groundwater supply + return flow) and demand from commercial, domestic, industrial, irrigation, livestock, mining, and thermoelectric uses. The Water Supply Stress Index and Water Supply Stress Index Ratio were developed to evaluate water stress conditions over time and across the 666 eight‐digit Hydrologic Unit Code basins in the 13 southeastern states. Predictions from two Global Circulation Models (CGC1 and HadCM2Sul), one land use change model, and one human population model, were integrated to project future water supply stress in 2020. We found that population increase greatly stressed water supply in metropolitan areas located in the Piedmont region and Florida. Predicted land use and land cover changes will have little effect on water quantity and water supply‐water demand relationship. In contrast, climate changes had the most pronounced effects on regional water supply and demand, especially in western Texas where water stress was historically highest in the study region. The simulation system developed by this study is useful for water resource planners to address water shortage problems such as those experienced during 2007 in the study region. Future studies should focus on refining the water supply term to include flow exchanges between watersheds and constraints of water quality and environmental flows to water availability for human use.     

Problems with mitigation translocation of herpetofauna

Mitigation translocation of nuisance animals is a commonly used management practice aimed at resolution of human–animal conflict by removal and release of an individual animal. Long considered a reasonable undertaking, especially by the general public, it is now known that translocated subjects are negatively affected by the practice. Mitigation translocation is typically undertaken with individual adult organisms and has a much lower success rate than the more widely practiced conservation translocation of threatened and endangered species. Nonetheless, the public and many conservation practitioners believe that because population‐level conservation translocations have been successful that mitigation translocation can be satisfactorily applied to a wide variety of human‐wildlife conflict situations. We reviewed mitigation translocations of reptiles, including our own work with 3 long‐lived species (Gila monsters [Heloderma suspectum], Sonoran desert tortoises [Gopherus morafkai], and western diamond‐backed rattlesnakes [Crotalus atrox]). Overall, mitigation translocation had a low success rate when judged either by effects on individuals (in all studies reviewed they exhibited increased movement or increased mortality) or by the success of the resolution of the human–animal conflict (translocated individuals often returned to the capture site). Careful planning and identification of knowledge gaps are critical to increasing success rates in mitigation translocations in the face of increasing pressure to find solutions for species threatened by diverse anthropogenic factors, including climate change and exurban and energy development. Problemas con la Mitigación por Traslocación de Herpetofauna     

Bestimmung von Spurenstoffen in Niederschlagsproben

A precipitation network consisting of 15 sites as part of the national project SANA was established to document and characterize the spatial and temporal changes of pollutants in the precipitation of East Germany. Long-term data records show a significant decrease of sulfate and calcium in the precipitation. The acidity and the nitrogen-containing ions have been remained unchanged up to now.     

Scaling up site disputes: strategies to redefine ‘local’ in the fight against fracking

Plans to replace an aging diesel backup energy plant with liquid natural gas (LNG) generators in Whitehorse, Yukon, resulted in a public outcry, involving community meetings, massive petitions, and demonstrations. Are these civil society protests just a case of a local siting dispute – a response to an unwanted industrial site in an urban neighborhood? Here, it is argued that siting debates are not the driver of these campaigns, but instead are harnessed by activists to advance a broader environmental movement. By linking the LNG project to more distant extraction, involving hydraulic fracturing (‘fracking’), movement leaders portray the entire territory as part of the ‘local’ for Whitehorse residents. Movement leaders rely upon two key mechanisms: claiming insider status, and identifying visible symbols. This case reveals the strategic use by environmental movements of local concerns to recruit support for broader campaigns, and the value of local, place-based activism for broader environmental movements.