Prey capture by Pisaster brevispinus (Asteroidea: Echinodermata) on soft substrate

Observations on the subtidal seastar Pisaster brevispinus (Stimpson) indicate that this predator can extend the central tube feet into sand-mud substrate for a distance roughly equal to the radius of the seastar. Field and laboratory evidence demonstrates the use of the elongated tube feet by the asteroid for the capture of burrowed prey items. A relationship between predator size and the size of juveniles of the deep-burrowing clam Tresus nuttallii taken as prey is a product of the ability of larger seastars to extend the tube feet further into the substrate and capture deeper prey. The role of P. brevispinus as an important subtidal predator along the Pacific Coast of North America is discussed.     

Projected Climate Change Effects on Winterkill in Shallow Lakes in the Northern United States

2 was obtained from the output of the Canadian Climate Center General Circulation Model. To illustrate the effect of projected climate change on lake DO characteristics, we present herein DO information simulated, respectively, with inputs of past climate conditions (1961–1979) and with a projected 2 × CO₂ climate scenario, as well as differences of those values. Specific parameters obtained were minimum under-ice and lake bottom DO concentration in winter, duration of under-ice anoxic conditions (<0.1 mg/liter) and low DO conditions (<3 mg/liter), and percentage of anoxic and low DO lake volumes during the ice cover period. Under current climate conditions winterkill occurs typically in shallow eutrophic lakes of the northern contiguous United States. Climate warming is projected to eliminate winterkill in these lakes. This would be a positive effect of climate warming. Fish species under ice may still experience periods of stress and zero growth due to low DO (<3 mg/liter) conditions under projected climate warming.     

Modelling impacts of alternative farming management practices on greenhouse gas emissions from a winter wheat–maize rotation system in China

Agricultural production plays an important role in affecting atmospheric greenhouse gas concentrations. Field measurements were conducted in Quzhou County, Hebei Province in the North China Plains to quantify carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions from a winter wheat–maize rotation field, a common cropping system across the Chinese agricultural regions. The observed flux data in conjunction with the local climate, soil and management information were utilized to test a process-based model, Denitrification–Decomposition or DNDC, for its applicability for the cropping system. The validated DNDC was then used for predicting impacts of three management alternatives (i.e., no-till, increased crop residue incorporation and reduced fertilizer application rate) on CO₂ and N₂O emissions from the target field. Results from the simulations indicated that (1) CO₂ emissions were significantly affected by temperature, initial SOC, tillage method, and quantity and quality of the organic matter added in the soils; (2) increases in temperature, initial SOC, total fertilizer N input, and manure amendment substantially increased N₂O emissions; and (3) temperature, initial SOC, tillage, and quantity and quality of the organic matter added in the soil all had significant effects on global warming. Finally, five 50-year scenarios were simulated with DNDC to predict their long-term impacts on crop yield, soil C dynamics, nitrate leaching losses, and N₂O emissions. The modelled results suggested that implementation of manure amendment or crop residue incorporation instead of increased fertilizer application rates would more efficiently mitigate GHG emissions from the tested agro-ecosystem. The multi-impacts provided a sound basis for comprehensive assessments on the management alternatives.     

Modelling economic impacts and adaptation to extreme events: Insights from European case studies

Adaptation to climate change in Europe has only recently become a true policy concern with the management of extreme events one priority item. Irrespective of future climatic changes increasing the need for systematic evaluation and management of extremes, weather-related disasters already today pose substantial burdens for households, businesses and governments. Research in the ADAM project identified substantial direct risks in terms of potential crop and asset losses due to combined drought and heatwave, as well as flood hazards in Southern and Eastern Europe, respectively. This paper focuses on the indirect, medium to longer term economic risks triggered by the direct risks and mediated by policy responses. We present a selection of three economic impact and adaptation assessments and modelling studies undertaken on extreme event adaptation in Europe. Responding to a need for more economically based adaptation assessments, we address some relatively unresearched issues such as the understanding of past adaptation, the role of market response to impacts as well as government’s ability to plan for and share out extreme event risks. The first analysis undertakes an empirical exploration of observed impacts and adaptation in the agricultural sector in the UK comparing the impact of consecutive extreme events over time in order to determine whether adaptation has occurred in the past and whether this can be used to inform future estimates of adaptation rates. We find that farmers and the agricultural sector clearly have adapted to extreme events over time, but whether this rate can be maintained into the future is unclear, as some autonomous adaptation enacted seemed rather easy to be taken. Markets may mediate or amplify impacts and in the second analysis, we use an economic general equilibrium model to assess the economic effects of a reduction in agricultural production due to drought and heatwave risk in exposed regions in Spain. The analysis suggests that modelled losses to the local economy are more serious in a large-scale scenario when neighbouring provinces are also affected by drought and heatwave events. This is due to the supply-side induced price increase leading to some passing on of disaster costs to consumers. The simulation highlights the importance of paying particular attention to the spatial and distributional effects weather extremes and possibly changes therein induced by climate change may incur. Finally, we discuss how national governments may better plan their disaster liabilities resulting from a need to manage relief and reconstruction activities post event. We do so using a risk based economic planning model assessing the fiscal consequences associated with the coping with natural extremes. We identify large weather-related disaster contingent liabilities, particularly in the key flood hot spot countries Austria, Romania, and Hungary. Such substantial disaster liabilities (“hidden disaster deficits”) when interacting with weak fiscal conditions may lead to substantial additional stress on government budgets and reduced fiscal space for funding other relevant public investment projects. Overall, our paper suggests the importance of respecting the specific spatial and temporal characteristics of extreme event risk when generating information on adaptation decisions. As our adaptation decisions considered, such as using sovereign risk financing instruments are associated with a rather short time horizon, the analysis largely focuses on the management of today’s extreme events and does not discuss in detail projections of risks into a future with climate change. Such projections raise important issues of uncertainty, which in some instances may actually render future projections non-robust, a constraint to be kept in mind when addressing longer term decisions, which at the same time should account for both climate and also socioeconomic change.     

Common criteria for the redefinition of Intermediate Less Favoured Areas in the European Union

This article defines eight key climate, soil and terrain criteria that have been developed for the future delimitation of the Intermediate Less Favoured Areas (LFAs) support, a measure of the Common Agricultural Policy. The LFA scheme has existed since 1975 and is a broad mechanism for improving the viability of agriculture in areas with natural handicaps. The common criteria have been developed for the European Commission's Directorate-General for Agriculture and Rural Development to satisfy the objectives in the Rural Development Policy 2007–2013 (Axis II), which aim to improve the environment and the countryside by more sustainable land management. The criteria were developed by experts, coordinated by the European Commissions Joint Research Centre, to meet the requirement for a robust and harmonised approach of identifying areas that experience natural constraints to agriculture throughout the EU 27 Member States. The criteria proposed are: temperature, heat stress, drainage, soil texture and stoniness, soil rooting depth, soil chemical properties, soil moisture balance and slope. Each criterion is described and an indicative threshold for assessment of its impact on agriculture is provided. The criteria are currently being tested by the EU Member States for a future possible legislation.     

Climate change and financial adaptation in Africa. Investigating the impact of climate change on the robustness of index-based microinsurance in Malawi

This paper discusses the applicability of crop insurance for the case of Malawi and explores the potential impact of climate change on the viability of the Malawi weather insurance program making use of scenarios of climate change-induced variations in rainfall patterns. The analysis is important from a methodological and policy perspective. By combining catastrophe insurance modeling with climate modeling, the methodology demonstrates the feasibility, albeit with large uncertainties, of estimating the effects of climate variability and climate change on the near- and long-term future of microinsurance schemes serving the poor. By providing a model-based estimate of insurance back-up capital necessary to avoid ruin under climate variability and climate change, along with the associated uncertainties and data limitations, this methodology can quantitatively demonstrate the need for financial assistance to protect micro-insurance pools against climate-induced insolvency. This is of major concern to donors, NGOs and others supporting these innovative systems, those actually at-risk and insurers providing insurance. A quantitative estimate of the additional burden that climate change imposes on weather insurance for poor regions is of interest to organizations funding adaptation. Further, by linking catastrophe modeling to regionalized climate modeling, the analysis identifies key modeling inputs necessary as well as important constraints. We end with a discussion of the opportunities and limits to similar modeling and weather predictability for Sub-Saharan Africa beyond the case of Malawi.

Chronosequence analysis of two enclosure management strategies in degraded rangeland of semi-arid Kenya

The establishment of enclosures has become an important measure to combat land degradation in many of the world's semi-arid rangelands. In view of the increased pressure exerted by this land reclamation strategy on the neighbouring agricultural lands, knowledge of the time required for restoring vegetation cover and soil health, and of the potential positive impact of an adapted management strategy, is highly required. This paper assesses the vegetation and soil rehabilitation in a 23-year chronosequence of two different enclosure management types. In the severely degraded, semi-arid Njemps Flats plain of the Lake Baringo Basin in Kenya communal enclosures characterised by high quality inputs and strict control, and private enclosures managed by individual farmers, were installed since the 1980s. Six communal enclosures (3–17 years since establishment) and six private enclosures (13–23 years since establishment) were selected. Vegetation cover was estimated along three 50 m transects set within each enclosure and in the adjacent open grazing area using the point-to-line transect method. Five 0.5 m² quadrats systematically placed alongside each transect were sampled for herbaceous standing biomass and topsoil physical, chemical and biological analyses. Grass cover and herbaceous biomass production proved to be the most responsive biotic parameters under both management types, whereas the recovery of the forbs was unsuccessful. Under communal management, the biomass production fully recovered up to its optimal level as recorded in the neighbouring nature reserves. Within private enclosures however, the adopted management strategies seriously restricted biomass production to a significantly lower level. Soil quality generally recovered more slowly with time. Significant improvements compared to the open rangeland were recorded in topsoil bulk density, organic C and total N stocks, and microbial biomass C and N stocks of the communal enclosures. Unlike the communal enclosures, only topsoil bulk density and the microbial biomass C stock showed a significant difference in the private enclosures. With respect to C and total N stocks, and the microbial biomass N a non-significant improving trend was recorded. The level of chemical and biological soil quality obtained under both management types is still low and draws the attention to the importance of careful monitoring of grazing and grass cutting activities under both enclosure management strategies. The chronosequences further highlight the potential of some well-managed private enclosures, whereas intrinsic soil properties such as high alkalinity, as well as changes in management, limit the rehabilitation of some other private as well as communal enclosures.     

Oxidation of As（Ⅲ） by potassium permanganate

The oxidation of As（Ⅲ） with potassium permanganate was studied under conditions including pH, initial As（Ⅲ） concentration and dosage of Mn（Ⅶ）. The results have shown that potassium permanganate was an effective agent for oxidation of As（Ⅲ） in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As（Ⅲ） by Mn（Ⅲ）. Although theoretical redox analyses suggest that Mn（Ⅶ） should have better performance in oxidization of As（Ⅲ） within lower pH ranges, the experimental results show that the oxidation efficiencies of As（Ⅲ） under basic and acidic conditions were similar, which may be due to the adsorption of As（Ⅲ） on the Mn（OH）2 and MnO2 resulting from the oxidation of As（Ⅲ）.     

Unraveling the causes of the toxicity of extremely acid waters of volcanic origin

A river ecosystem in East Java, Indonesia, fed by a volcanic lake with high concentrations of dissolved metals and a low pH, was found to support only few macroinvertebrates. To unravel the causes of toxicity and to determine the level of dilution necessary to obtain non-toxic water, a bioassay was conducted with the fairy shrimp Thamnocephalus platyurus. A partial toxicity identification evaluation (TIE) approach was used with EDTA as a chelating agent to relate toxicity to pH and metal concentrations. Three water samples were tested, with pHs ranging from 0.72 to 4.5, and diluted with water from a neutral river to different degrees. The dilution factor necessary to achieve no more than 50% mortality in the Thamnotox test (Ldf(50)) varied from >300 at the most acidic site, to 7 for water of pH 2.6 and 1.5 for water of pH 4.5. Toxicity was best explained from both low pH and high concentrations of metals, especially Al and Fe. The key role of Al and Fe in the toxicity was confirmed by relating concentrations of the different compounds in the river water to toxicity data from the literature. EDTA addition did not significantly influence Ldf(50) or the lethal pH 50% (LpH(50)), suggesting a large effect, besides cationic components and pH, of anions (F, SO(4) and Cl).