Conservation ecology of boreal polypores: A review

Here we quantitatively summarize the conservation ecology of one group of dead-wood-dependent organisms, the polyporous fungi, in boreal Europe. At the substrate scale, the decay stage is the strongest determinant of species richness, with large (>20 cm diameter) downed logs hosting more species than other dead-wood types. At the stand scale, the amount of dead wood is the strongest determinant of polypore species richness; the minimum average amount of dead wood for the occurrence of rare polypores appears to be 20–40 m³/ha. Species-area analysis shows that in mature boreal forests species accumulation levels off at around 20–30 ha. This leads us to suggest a heuristic 20/20/20 rule of thumb: a 20 ha stand, with an average of 20 m³/ha of dead wood of which many are logs >20 cm, is likely to be the minimum for the ecologically justified conservation of polypore diversity at the stand scale in boreal Europe. Equally crucial for polypore diversity, however, is the current and historic extent of suitable habitats at the landscape scale. The time lag between the isolation of a habitat patch and the new equilibrium in the number or occurrence of species seems to be around 100–150 years, indicating that an extinction debt is likely to exist in recently isolated fragments. Only a few studies have addressed the ecological efficiency of the new, biodiversity-oriented forest management tools (retention trees, woodland key habitats). Despite this it seems that the traditional large conservation areas are the most effective means of polypore conservation.     

Rescue of the Seychelles warbler on Cousin Island, Seychelles: the role of habitat restoration

Management policies to save threatened species are not always successful, often due to the lack of a scientific basis and evaluation of the species response. We describe the ecological studies and the conservation actions taken between 1985 and 1992 on Cousin Island (29 ha, Seychelles) to safeguard the future of the highly threatened Seychelles warbler (Acrocephalus sechellensis), which until 1988 only occurred on this island. A detailed field study was designed to (1) identify the key processes influencing warbler demography, (2) identify appropriate management techniques to increase the warbler population, and (3), assess the influence of the resulting habitat management. Since 1980 the island has been saturated with c. 115 territories and c. 320 birds. The warbler is purely insectivorous. Morinda (Morinda citrifolia), the most insect rich tree, is preferred for foraging. The higher the insect abundance (and Morinda cover) in territories the higher the reproductive success and survival of warblers. Insect numbers were highest in the central part of Cousin and decreased towards the coast. Coastal territories protected by a salt tolerant hedge of Scaevola (Scaevola taccada) had more insects and higher reproductive success than unprotected territories. Between 1990 and 1992 Morinda trees were planted on the island and Scaevola along the coast. Although these habitat restoration measures have not resulted in higher numbers of adult warblers and territories due to habitat saturation, they have been successful in terms of improving the quality of existing breeding territories and with that the reproductive success of breeding birds (including the number of territories producing recruits), and the exchange of individuals (genetic material) between territories. We provide evidence that the high reproductive potential of this species is likely to improve the resilience of the species to catastrophic events.     

Conservation justice in metropolitan Cape Town: A study at the Macassar Dunes Conservation Area

Conservation justice, a concept analogous to environmental justice, suggests that local communities are entitled to receive fair treatment and meaningful involvement in the development and implementation of conservation policy. In this study, of an urban conservation project in Cape Town, South Africa, we contribute to the ongoing conversation about the importance of community-based conservation approaches. Conservationists must work to plan and implement projects in ways that are not only acceptable to stakeholders, but inspire local community involvement in achieving conservation goals. Given its location in the impoverished Cape Flats region of metropolitan Cape Town and its unique ecological and conservation value, the Macassar Dunes Conservation Area warrants a conservation justice approach. We conducted semi-structured interviews with members of interested and affected communities, then analyzed stakeholder perspectives on biodiversity protection, fencing, and informal housing. The results suggest that despite disparity among groups in needs and perspectives, conservation projects have potential to deliver tangible benefits to all stakeholder groups. A belief in conservation is universal across stakeholder lines, but contrasting needs and perspectives of the studied groups lead to conflicting views on important issues of implementation. An understanding of different stakeholder groups’ specific needs and interests is therefore essential for successful implementation of sustainable urban conservation projects.     

Studies on the metabolism in roots of lowland rice

In the previous studies we investigated some characteristics of paddy root in comparison with shoot by analysis of inorganic elements¹⁾ and metabolizable forms of organic compounds²⁾ of shoot and root at successive growth stages, and found that the contents of the above-mentioned components in root were generally lower than those in shoot with few exceptions. From this it is concluded that in root the contents of the residual components, mainly cell wall substances, must be high. To ascertain this surmise, we carried out analysis of shoot, root and inflorescences of rice plant with respect to hemicellulose, cellulose and lignin which construct cell walls.     

Studies on the metabolism in roots of lowland rice

In the previous papers¹⁾ we investigated the seasonal changes in mineral and organic compositions of root, shoot and inflorescence of paddy rice, and pointed out some characteristics of root from the viewpoint of their composition.     

The changing extent and conservation interest of lowland grasslands in England and Wales: A review of grassland surveys 1930–1984

This study has examined the changing extent of lowland grassland, in England and Wales, over the last half century. The proportions of semi-natural, and agriculturally improved grasslands were also assessed.

Total grassland area has declined from 7·8 M ha, 50 years ago, to just 4·8 M ha now. The decline in extent of unimproved grasslands also started in the 1930s, accelerated through the war years, and has continued steadily ever since. The main agents, at first, were drainage and the plough. However, inorganic fertiliser use has increased simultaneously, improving even old unploughed grasslands.

Only 0·6 M ha of semi-natural and rough grasslands remain in lowland England and Wales, making up only 11% of the total grassland area. Semi-natural pastures excluding rough grasslands now cover only 0·2 M ha, 4% of the present-day grassland area and 3% of its area 50 years ago. Semi-natural pastures which survive have often seen some agricultural improvements, so that relatively few retain their conservation interest.     

A model for predicting the fate of nitrogen fertilizer in lowland ricefields

Equations are developed for the simultaneous movement and reaction in flooded soils of urea, ammoniacal species, carbonate species, and acids and bases, the simultaneous uptake of N by a developing rice root system, and losses of NH₃ and CO₂ by volatilization from the floodwater. The equations allow for the initial distribution of urea and other reactants in the soil and floodwater, for movement both by diffusion and convection, and for the rates of urea hydrolysis, floodwater algal activity, organic-C and -N mineralization, and H+ release from roots to balance excess uptake of cations over anions. The equations are combined in a computer model which can predict the fate of N fertilizer in lowland ricefields for any combination of crop and environmental conditions.     

浅析农学专业英语的特点和翻译

本文主要论述了农学专业英语的特点,并结合这些特点总结了常用的农学英语文章翻译原则,然后提出了如何正确的翻译农学英语的策略,并最终能达到能准确、客观、精练翻译农学英语的目的。     

HeathMod: a model of the impact of seasonal grazing by sheep on upland heaths dominated by Calluna vulgaris (heather)

The dwarf shrub heather Calluna vulgaris is an important component of the UK landscape, with value for amenity, nature conservation and animal production. A model, called “HeathMod”, is described, which investigates the impact of grazing on upland heather. It combines an empirical model of production with a simple process-based model of grazing impacts. Validation from short-term studies in the literature indicated that the model predicts grazing impacts well, although more studies of grazing impacts are required to confirm the model’s accuracy. Analysis of the model allowed derivation of a simple general formula for predicting sustainable levels of grazing, given knowledge of local site productivity. Predicted levels of sustainable grazing were lower than previous estimates, mainly because the model predicts the long-term impacts of sustained grazing. Application of the model is most appropriate in areas where heather is in mixed-age stands, because there is inadequate information available to model interactions between grazing and degeneration in even-aged stands of heather.     

Impacts of grazing on lowland heathland in north-west Europe

Lowland heathland habitats are recognized to be of high conservation value throughout north-west Europe. Current management approaches focus on arresting natural succession to woodland, and include the use of vegetation cutting, burning and grazing by livestock. However, the introduction of grazing has proved controversial, highlighting the need for evidence regarding its effectiveness. A systematic review of the scientific literature was therefore performed, which identified 13 studies with appropriate comparators (such as untreated controls). Meta-analysis of these data indicated that grazing can result in an increase in the ratio of grassland to ericoid shrub cover, but insufficient experimental evidence was available to assess the effectiveness of any other intervention, indicating a lack of replicated studies with controls. Two forms of expert knowledge were also compiled, based on information in the scientific literature excluded from the meta-analysis, and questionnaire responses of heathland managers. While these two evidence sources were generally in close correspondence, beliefs of heathland managers contradicted the scientific literature with respect to the impact of grazing on the ratio of grassland to ericoid shrubs. Incorporating a range of evidence sources in systematic reviews can therefore provide insights into contradictions in the evidence base. While a large majority of practitioners (94%) believe that grazing is an effective management option for lowland heath, evidence for a number of negative impacts on habitat attributes was recorded, highlighting the need for improved monitoring and experimental analysis of the effectiveness of management interventions.     

A global assessment of the impact of fisheries-related mortality on shy and white-capped albatrosses: Conservation implications

Hundreds of thousands of seabirds are killed each year as a result of interacting with longline and trawl fishing operations, and the severity of the impact varies regionally. Shy and white-capped albatrosses, Thalassarche cauta and Thalassarche steadi respectively, are phenotypically similar species known to be incidentally killed by fishing operations. The magnitude of this mortality has not previously been assessed across their range. Here we examine recent effort and bycatch rates in fisheries known to incidentally kill these species and qualitatively evaluate the level of impact of each fishery. Results indicate that over 8500 of these albatrosses may be killed annually, although the reliability of this estimate is low due to the paucity of comprehensive observer data in most fisheries. Of the estimated deaths of all seabird species in the fisheries assessed, trawl and longline fisheries killed birds in approximately equal proportions, but when the mortality levels of shy-type albatrosses were examined, trawl fisheries were responsible for 75% of all deaths. Data suggest most of these birds were killed in South African, Namibian and New Zealand demersal trawl fisheries and the South Africa pelagic longline fishery. Because most adult shy albatrosses are comparatively sedentary and rarely found outside Australian waters, it is primarily juvenile shy albatrosses that regularly encounter fishing fleets known to kill large numbers of albatrosses. In contrast, throughout most of their range juvenile and adult white-capped albatrosses are exposed to fisheries that collectively kill many thousands of these albatrosses each year. These data emphasise the urgent need for robust assessments of the impact of bycatch at a species and population level, and the urgent implementation of effective mitigation measures.     

浅谈水土保持学科体系的组成

水土保持科学研究的对象包括防治水土流失和合理利用水土资源两方面 ,水土保持学科体系包括水土流失规律、水土保持技术措施、水土保持规划、水土保持管理和水土保持效益等几方面。     

Conservation value of tropical secondary forest: A herpetofaunal perspective

In some areas of the tropics forests are recovering on abandoned cattle pastures. These secondary forests may be important habitats for conserving biodiversity, but we know little about their species composition over the long term. We studied herpetofaunal community changes in a 40 years chronosequence of forest succession on abandoned pastures in Puerto Rico. Twelve submontane sites (100-250 masl) represented four forest recovery stages: pasture, young (1-5 years after abandonment), intermediate (10-20 years), and advanced (40 years). Among these stages we analyzed the relationship of forest structure, microclimate, and herpetofaunal community structure. During succession total forest height increased, new strata of vegetation appeared in the understory, and the forest gained heterogeneity and complexity. Microclimate changed with changes in the physiognomy and structure of the vegetation. Microclimatic shifts were more dramatic in forest <20 years since abandonment. During 1 year we observed 7991 individuals of thirteen reptilian species (60% of observations) and six anuran species. Herpetofaunal richness was similar among stages, but the total abundance increased through succession. Relative abundance of anurans and reptiles was similar between stages, but species dominance changed with succession. Forest >20 years old resembles mature forest in some structural characteristics important to herpetofauna and can provide habitat for forest herpetofauna in disturbed areas.     

浅谈沙土保持工程监理

监理公司在取得工作任务后，应及时组建项目监理机构。在总监理工程师主持下，根据业主对项目监理的要求，针对项目的具体情况编写监理规划，各专业监理工程师根据监理规划，对所负责专业的监理工作编制实施细则。介绍了水土保持工程措施工监理的具体要求和监理内业工作。     

浅谈水土保持工程监理

监理公司在取得工作任务后,应及时组建项目监理机构。在总监理工程师主持下,根据业主对项目监理的要求,针对项目的具体情况编写监理规划,各专业监理工程师根据监理规划,对所负责专业的监理工作编制实施细则。介绍了水土保持工程措施施工监理的具体要求和监理内业工作。     

Conservation cornerstones: Capitalising on the endeavours of long-term monitoring projects

Ecological monitoring is widely used to measure change through time in ecosystems. The current extinction crisis has resulted in a wealth of monitoring programs focussed on tracking the status of threatened species, and the perceived importance of monitoring has seen it become the cornerstone of many biodiversity conservation programs. However, many monitoring programs fail to produce useful outcomes due to inherent flaws. Here we use a monitoring program from south-eastern Australia as a case study to illustrate the potential of such endeavours. The threatened carnivorous marsupial, the brush-tailed phascogale (Phascogale tapoatafa), has been monitored at various locations between 2000 and 2010. We present strong evidence for a decline in relative abundance during this period, and also describe relationships with environmental variables. These results provide insights likely to be valuable in guiding future management of the species. In the absence of the monitoring program, informed management would not be possible. While early detection of population declines is important, knowledge of the processes driving such declines is required for effective intervention. We argue that monitoring programs will be most effective as a tool for enhanced conservation management if they test specific hypotheses relating to changes in population trajectories. Greater emphasis should be placed on rigorous statistical analysis of monitoring datasets in order to capitalise on the resources devoted to monitoring activities. Many datasets are likely to exist for which careful analysis of results would have benefits for determining management directions.     

浅谈水土保持法存在的几个问题

《中华人民共和国水土保持法》(以下简称《水土保持法》)自 1991年颁布实施至今 ,为减少人为水土流失、保护自然环境 ,发挥了巨大的作用 ,但在实施过程中也逐渐暴露出一些问题 ,甚至影响了水土保持预防监督工作的正常开展。笔者作为一名水土保持预防监督工作者 ,现对《水土保持     

Greenhouse crops: A review

Concerns over increasing production costs and decline in crop revenues have prompted the greenhouse industry to reevaluate criteria used to select crops for greenhouse systems. In the past, crop selection was primarily based on profitability and the strategy was to manipulate the environment to tailor it to the requirements of the crop. As greenhouses are currently evolving from high energy‐consuming to cost‐efficient systems, an emerging strategy is to manipulate the crop to meet the characteristics of the greenhouse environment. To ensure efficient crop manipulation, however, an in‐depth understanding is needed of the inherent ability of crops to adapt and render economic yields under suboptimal conditions. This paper reviews key features of selected greenhouse crops, assesses the impact of changing environment on crop performance, and examines potential avenues for crop manipulation.