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.     

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     

Impacts of climate change on land-use and wetland productivity in the Prairie Pothole Region of North America

Wetland productivity in the Prairie Pothole Region (PPR) of North America is closely linked to climate. A warmer and drier climate, as predicted, will negatively affect the productivity of PPR wetlands and the services they provide. The effect of climate change on wetland productivity, however, will not only depend on natural processes (e.g., evapotranspiration), but also on human responses. Agricultural land use, the predominant use in the PPR, is unlikely to remain static as climate change affects crop yields and prices. Land use in uplands surrounding wetlands will further affect wetland water budgets and hence wetland productivity. The net impact of climate change on wetland productivity will therefore depend on both the direct effects of climate change on wetlands and the indirect effects on upland land use. We examine the effect of climate change and land-use response on semipermanent wetland productivity by combining an economic model of agricultural land-use change with an ecological model of wetland dynamics. Our results suggest that the climate change scenarios evaluated are likely to have profound effects on land use in the North and South Dakota PPR, with wheat displacing other crops and pasture. The combined pressure of land-use and climate change significantly reduces wetland productivity. In a climate scenario with a +4 °C increase in temperature, our model predicts that almost the entire region may lack the wetland productivity necessary to support wetland-dependent species.     

The research-policy nexus in climate change adaptation: experience from the urban water sector in South East Queensland,Australia

Despite an exponential growth in the volume of adaptation research over the last decade, there is still a research gap in regard to the provision of suitable information to adequately inform climate change adaptation policy makers. Contributing to this gap is a paucity of research reporting on the effectiveness of implemented adaptation strategies. This paper reports on the success, failures and future risks of the responses taken by the South East Queensland (SEQ) water sector during the Millennium Drought. The adaptation strategy employed a portfolio approach mixing ‘hard’ and ‘soft’ adaptations. Strategies included the following: large-scale water manufacturing facilities and distribution networks; the exploitation of local water resources; regulatory instruments; institutional reforms; support for research and training and a range of demand management programmes. The strategies employed were innovative and in many cases required rigorous scientific evidence for their development, implementation and follow-up assessments. However, we show that there has been considerable disparity between anticipated and actual policy outcomes, which points to maladaptive consequences. By revisiting the effectiveness of implemented adaptation strategies in the SEQ water sector, our paper provides evidence for the need for integrative studies with genuine policy integration.     

Bioavailability of iodine in the UK-Peak District environment and its human bioaccessibility: an assessment of the causes of historical goitre in this area

Iodine is an essential micronutrient for human health. Its deficiency causes a number of functional and developmental abnormalities such as goitre. The limestone region of Derbyshire, UK was goitre-endemic until it declined from the 1930s and the reason for this has escaped a conclusive explanation. The present study investigates the cause(s) of goitre in the UK-Peak District area through an assessment of iodine in terms of its environmental mobility, bioavailability, uptake into the food chain and human bioaccessibility. The goitre-endemic limestone area is compared with the background millstone grit area of the UK-Peak District. The findings of this study show that ‘total’ environmental iodine is not linked to goitre in the limestone area, but the governing factors include iodine mobility, bioavailability and bioaccessibility. Compared with the millstone grit area, higher soil pH and calcium content of the limestone area restrict iodine mobility in this area, also soil organic carbon in the limestone area is influential in binding the iodine to the soil. Higher calcium content in the limestone area is an important factor in terms of strongly fixing the iodine to the soil. Higher iodine bioaccessibility in the millstone grit than the limestone area suggests that its oral bioaccessibility is restricted in the limestone area. Iodine taken up by plant roots is transported freely into the aerial plant parts in the millstone grit area unlike the limestone area, thus providing higher iodine into the human food chain in the millstone grit area through grazing animals unlike the goitre-prevalent limestone area.     

Microbially assisted phytoremediation approaches for two multi-element contaminated sites

Phytoremediation is an environmental friendly, cost-effective technology for a soft restoration of abandoned mine sites. The grasses Agrostis capillaris, Deschampsia flexuosa and Festuca rubra, and the annual herb Helianthus annuus were combined with microbial consortia in pot experiments on multi-metal polluted substrates collected at a former uranium mine near Ronneburg, Germany, and a historic copper mine in Kopparberg, Sweden, to test for phytoextraction versus phytostabilization abilities. Metal uptake into plant biomass was evaluated to identify optimal plant–microbe combinations for each substrate. Metal bioavailability was found to be plant species and element specific, and influenced by the applied bacterial consortia of 10 strains, each isolated from the same soil to which it was applied. H. annuus showed high extraction capacity for several metals on the German soil independent of inoculation. Our study could also show a significant enhancement of extraction for F. rubra and A. capillaris when combined with the bacterial consortium, although usually grasses are considered metal excluder species. On the Swedish mixed substrate, due to its toxicity, with 30 % bark compost, A. capillaris inoculated with the respective consortium was able to extract multi-metal contaminants.     

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.     

An Institutional and Opinion Analysis of Colorado’s Hydraulic Fracturing Disclosure Policy

Hydraulic fracturing and oil and natural gas development are possibly the most contentious energy and environmental issues to face the USA in the twenty-first century. One point of contention is the disclosure of fluids used in the hydraulic fracturing process. This paper analyses the Colorado 2011 policy requiring disclosure of hydraulic fracturing fluid information, considered one of the first comprehensive hydraulic fracturing disclosure policies in the country. We conduct an institutional analysis of the disclosure policy to understand how the policy establishes information flows and grants and restricts choices by targeted actors. We then analyse the opinions of people actively involved in hydraulic fracturing debates in Colorado to assess whether they view the disclosure policy as resolving problems. The institutional analysis illustrates how the policy allocates responsibilities in sending and receiving information and the opinion survey shows divergence in perceptions of its potential to resolve problems associated with chemical use or disclosure. Most respondents are in agreement that the new policy failed to build public trust of the hydraulic fracturing process.     

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.