Comparative diet selection by cattle and sheep grazing two contrasting heathland communities

In the UK the funding mechanism for moorland restoration is being implemented primarily through agri-environment schemes, yet to date remarkably few comparative grazing studies with domesticated livestock have been conducted on this type of vegetation community. In this experiment the diet composition of four groups of animals grazing heathland swards with low (8%) and high (61%) percentages of cover of Calluna vulgaris was estimated from faeces profiles of n-alkanes and long-chain fatty alcohols. Two breeds of sheep (Welsh Mountain (WM) and Scottish Blackface (SBF)), and two breeds of cattle (Welsh Black (WB) and Continental cross (CX)) grazed the experimental sites during two separate 14-day sampling sessions, in July and September respectively. Both species were selective feeders, consuming grasses (selectivity indices 0.20–1.0) in preference to dwarf shrubs (selectivity indices 0.20–1.0), but there were significant differences in the proportions of various plant groups within the diets. Although the sheep diets contained significantly more C. vulgaris, the quantities consumed were small (<10% of the diet), even on the High site, reflecting the biomass of the graminoid species present, and hence availability of preferred items. The SBF sheep were the only animal type to increase consumption of C. vulgaris later in the season. There were a number of significant differences in the composition of the diets selected by the two hill breeds of sheep used in the study, with the SBF sheep recorded as consuming more C. vulgaris. These results imply that through choice of breed land managers may be able to meet environmental goals more effectively without compromising returns from conventional production systems. In contrast, the overall diet composition of the two breed types of cattle was similar. This indicates that commercial breeds have the potential to deliver the types of environmental benefits associated with grazing of traditional breeds.     

Review and meta-analysis of 82 studies on end-of-life management methods for source separated organics

This article reports on a literature review and meta-analysis of 82 studies, mostly life cycle assessments (LCAs), which quantified end-of-life (EOL) management options for organic waste. These studies were reviewed to determine the environmental preferability, or lack thereof, for a number of EOL management methods such as aerobic composting (AC), anaerobic digestion (AD), gasification, combustion, incineration with energy recovery (often denoted as waste-to-energy incineration), mechanical biological treatment, incineration without energy recovery (sometimes referenced by just the word “incineration”), and landfill disposal with and without energy recovery from generated methane. Given the vast differences in boundaries as well as uncertainty and variability in results, the LCAs among the 82 studies provided enough data and results to make conclusions regarding just four EOL management methods – aerobic composting, anaerobic digestion, mass burn waste-to-energy (WTE), and landfill gas-to-energy (LFGTE). For these four, the LCAs proved sufficient to determine that aerobic composting and anaerobic digestion are both environmentally preferable to either WTE or LFGTE in terms of climate change impacts.For climate change, LCA results were mixed for WTE versus LFGTE. Furthermore, there is a lack of empirically reliable estimates of the amount of organics input to AD that is converted to energy output versus remaining in the digestate. This digestate can be processed through aerobic composting into a compost product similar to the compost output from aerobic composting, assuming that the same type of organic materials are managed under AD as are managed via AC. The magnitude of any trade-off between generation of energy and production of compost in an AD system appears to be critical for ranking AC and AD for differing types of organics diversion streams. These results emphasize how little we generally know, and exemplify the fact that in the reviewed literature no single EOL management method consistently topped all other management options across all environmental impacts, and that future studies must strive to match existing analytical boundaries and alternatives assessed to increase knowledge if as a community we expect to be able to make even more generalized conclusions.     

A framework for assessing the impact of the IPPC directive on the performance of the pig industry.

New European Union legislation on Integrated Pollution Prevention and Control (IPPC) is being implemented in the United Kingdom, enacted by the Pollution Prevention and Control Act 1999 and its statutory instruments, the Pollution Prevention and Control (England and Wales) Regulations 2000. This legislation incorporates previously unregulated installations in the food and intensive livestock sectors, such as pig installations above a given threshold size. IPPC requires that installations adopt Best Available Techniques and follow General Binding Rules of good practice in order to manage their environmental effects. IPPC has significant potential impacts for both the environmental and financial performance of the pig industry. In this context, the paper discusses the IPPC implementation process as it applies to the sector and presents a methodological framework for assessing the environmental and cost benefit implications of the new regulations.     

Osmotic, ionic and haematological response of the Port Jackson shark Heterodontus portusjacksoni and the common stingaree Trygonoptera testacea upon exposure to diluted seawater

The osmo-ionoregulatory responses of sub-adult Port Jackson sharks, Heterodontus portusjacksoni (Meyer, 1793), and the stingaree Trygonoptera testacea (Müller and Henle, 1841), were investigated following the transfer from full-strength seawater (100% SW) to either 75 or 50% SW for up to 168 h. The plasma osmotic pressure was similarly reduced in both species and remained slightly hyper-osmotic to the diluted seawater after 168 h. The increase in the body weight of H.␣portusjacksoni transferred to diluted seawater was double that of T.testacea, with the greater haemodilution reflected by a short-term reduction in haematocrit and in haemoglobin concentration. The haemodilution exhibited by H. portusjacksoni also resulted in a greater reduction in plasma [Na], [Cl], [urea] and [trimethylamine oxide] compared with T. testacea. The ability of T. testacea to minimize body-weight gain in diluted seawater was most probably due to increased net water efflux. The persistent elevation in the body weight of both species, despite the apparent recovery of plasma-water volume, was indicative of elevated tissue water. Chronic exposure of H. portusjacksoni to 50% SW altered erythrocyte ion concentrations and plasma/erythrocyte ion ratios, which could have serious implications for cellular homeostasis, respiratory gas transport and acid-base status. The greater control of water and ionic status exhibited by T.testacea, compared with that of H.portusjacksoni, allows the stingarees to penetrate into the more dilute, upper estuarine waters. Received: 22 August 1997 / Accepted: 1 April 1998     

Co-composting of paper mill sludge and hardwood sawdust under two types of in-vessel processes

Recycling of organic residues by composting is becoming an acceptable practice in our society. Co-composting dewatered paper mill sludge (PMS) and hardwood sawdust, two readily available materials in Canada, was investigated using uncontrolled and controlled in-vessel processes. The composted materials were characterized for total C and N, water-soluble, acid-hydrolyzable, and non-hydrolyzable N, extractable lipids, and by Fourier Transform Infrared (FT-IR) spectrophotometry. In the controlled scale process, the loss of organic matter was approximately 65% higher than in the uncontrolled process. After undergoing initial fluctuations in N fractions during the first two days of composting, by the end of the process, concentrations of water-soluble N decreased while those of acid-hydrolyzable and nonhydrolyzable N increased in the controlled process, whereas in the uncontrolled process, water-soluble N increased, but N in the other two fractions decreased continuously, indicating that the biochemical transformations of organic matter were not completed. Data on extractable lipids and FT-IR spectra suggest that the compost produced from the controlled process was bio-stable after 14 days, while the uncontrolled process was not stabilized after 18 days. In addition, FT-IR data suggest the biological activity during composting centered mainly on the degradation of aliphatic structures while aromatic structures were preserved. The co-composting of the PMS and hardwood sawdust can be successfully achieved if aeration, moisture, and bio available C/N ratios are optimized to reduce losses of N.     

Documenting lemming population change in the Arctic: Can we detect trends?

Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.