Natural fire management in National Parks

An evolving understanding of ecological processes, together with ambiguities in National Park Service policy, have led to multiple interpretations of the role of management in our large natural area National Parks. National Park Service management policies must be dynamic and responsive to changes in scientific knowledge and societal values. We propose that the principal aim of NPS resource management in natural areas is the unimpeded interaction of native ecosystem processes and structural elements. The case of the changing role of natural fire management is used as an example in developing this rationale.     

Environmental equity in the vicinity of Amsterdam Airport: The interplay between market forces and government policy

This paper examines the impact of the interplay between market forces and government policy on environmental equity in the vicinity of Amsterdam Airport in the Netherlands. Despite pressure on space and the presence of the international airport, exposure to the higher levels of traffic noise, NO₂ and external safety risks, and accumulation of traffic noise and NO₂ (‘bads’) was rather limited and generally distributed fairly equally among income categories, probably as a result of environmental regulations. However, lower-income categories had less access to lower levels of traffic noise, NO₂ and public green space (‘goods’) than higher-income categories, which may be explained by both historical processes and market forces. Policy makers seem to accept a higher environmental burden on the regional population because of the benefits for the national economy generated by Amsterdam Airport.     

Dynamic Control Switching Applied to Water Resource Management Simulation1

Abstract: Simulation of water resource management in hydrological numerical models is often limited to simple expressions such as rulecurves. More complex management requires additional layers of abstraction. Rulecurves tend to be simplistic, while abstraction implies expertise to convert management policies to a form which may not be recognizable by operators. The Regional Simulation Model (RSM) attempts to bridge this gap with the Management Simulation Engine (MSE). MSE allows dynamic switching of control algorithms facilitating hybrid control of modeled structures, even though the individual controllers are widely different. Use of hybrid controllers can simplify expression of complex management controls. This article details the architecture of the MSE that enables hybrid control. A model application is examined in which a set of tuned fuzzy controllers are dynamically switched with piecewise linear flood controllers to simulate a hybrid control scheme. The application models a Florida water conservation area and demonstrates effective flood control without sacrificing the tuned performance of the fuzzy controllers.     

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.     

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.     

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.     

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).