Is regression what you really want?

Abstract. Regression is frequently abused in soil research. Its proper use is for statistical prediction. It may also be used to calculate equations for calibration. A regression equation may be used to express a functional relation between two soil variables that are thought to be related by some simple mathematieal law but only where one of the variables is known exactly. In most other circumstances regression is inappropriate. Where departures from a functional relation are due to errors of measurement and sampling fluctuation it should be replaced by a structural analysis to find the best equation. Where the underlying relation is truly bivariate it should be described as such.     

Acidic deposition: What is fact,what is speculation,what is needed?

In this presentation research findings from the symposium and from the literature are utilized to examine some of the major hypotheses that link acidic deposition with impairment of forest health and productivity in central Europe and eastern North America. Although unequivocal evidence of acid rain damage may be lacking, there is a considerable body of knowledge that implicates air pollutants in recent interference with forest nutrition and health. The nature of the evidence and the inferences that can be drawn from it are still being vigorously debated. The problem of verifying the mechanisms by which air pollutants affect forests still remains. Reports that climatic irregularities have acted as inciting or triggering factors in forest declines are relevant to understanding regional damage. More emphasis on experimental studies that assess interactions of air pollutants and natural stresses with forests is needed.     

Legal aspects of soil conservation and land cadaster works

The analysis of modern Russian legislation in the sphere of environmental protection, management of natural resources, soil conservation, and land cadaster works has been performed. It is shown that a common federal approach to environmental impact assessments and soil quality assessments is virtually absent. Ecological indices are not taken into account in the federal land cadaster. Most of the recently adopted legislative regulations in this sphere have a technocratic character. The recent governmental regulations on land and environmental monitoring have still not been put into practice. To ensure soil conservation policy and protect soils as a component of the environment, a distinction should be made between the notions of soil and land in the legal documents. The basic principles of the proposed law “On Soil Conservation” are outlined. It is argued that a system of soil-ecological criteria should be elaborated for the proper assessment of soil quality. As a soil conservation service is absent in Russia, it is suggested that the Dokuchaev Soil Science Society should organize an association for the protection and rehabilitation of Russian soils.     

Sewage works as bird habitats in Britain

The bird communities associated with different systems of sewage disposal are described in relation to the components of each system. The data were drawn from published studies and from British Trust for Ornithology data in the Common Birds Census and Register of Ornithological Sites. The bird communities were considered under four divisions: breeding, summer feeding, spring and autumn, winter. The ornithological gains and losses associated with recent changes in methods of sewage treatment are discussed, particularly in relation to the decline of sewage farms. It is concluded that modern works, which are on average smaller in area than sewage farms, support lower populations of wetland species. The variety of ornithological interest is also lower but it is suggested that modern works can be important bird habitats, particularly as feeding sites for several passerine species. Those systems with percolating filters and tertiary treatment by surface irrigation are likely to support the most varied bird communities. Works using other oxidation methods, and no tertiary treatment, are of the least value as bird habitats.     

Relationships among rainfall, runoff and soil loss for the design of soil and water conservation works in submontane Punjab

Abstract. Linear, exponential and power function regressions were compared for rainfall, runoff and soil loss data. The power function performed better (R²= 0.77) than exponential or linear functions for estimating runoff from daily rainfall. However, this relationship was improved (R²= 0.96) by inclusion of a random component to the deterministic part of the function. A linear relationship between runoff and soil loss data performed better (R²= 0.77) than exponential or power functions. These relationships help in designing soil and water conservation works for supplemental irrigation in the area.     

Relationship between fluoride contents and loss of lichens near an aluminium works

The relationship between F contents and damage to previously unpolluted saxicolous lichens (Ramalina sp) was examined in the vicinity of an Al works on the island of Anglesey, North Wales. Damage was greatest <2 km from the works, where 41% of Ramalina thalli showed >50% chlorosis and necrosis. Loss of lichens (measured by changes in percent cover in 58 permanent quadrats) decreased with increasing distance from the works. Lichens well-exposed to emissions had the largest F content and 20 to 30% more losses than those less-exposed. Well-exposed lichens had rates of loss of cover of 4.9% km^?1 yr^?1, whereas more sheltered thalli had losses of 3.7% km^?1 yr^?1. In contrast, relatively uncontaminated lichens increased in % cover. Content of F reflected both distance from the works and exposure to emissions; losses, and F content, were closely related (r²=0.90). Lichens containing 300, 100 and 50 μg F g^?1 dry weight lost 46, 15 and 10% of cover yr^?1, respectively.     

Improving the nutritional status of food-insecure women: first, let them eat what they like

OBJECTIVE: To determine the extent to which identified nutrient inadequacies in the dietary intakes of a sample of food-insecure women could be ameliorated by increasing their access to the 'healthy' foods they typically eat. DESIGN: Merged datasets of 226 food-insecure women who provided at least three 24-hour dietary intake recalls over the course of a month. Dietary modelling, with energy adjustment for severe food insecurity, explored the effect of adding a serving of the woman's own, and the group's typically chosen, nutrient-rich foods on the estimated prevalence of nutrient inadequacy. SETTING AND SUBJECTS: One study included participants residing in 22 diverse community clusters from the Atlantic Provinces of Canada, and the second study included food bank attendees in Toronto, Ontario, Canada. Of the 226 participants, 78% lived alone with their children. RESULTS: While nutritional vulnerability remained after modelling, adding a single serving of either typically chosen 'healthy' foods from women's own diets or healthy food choices normative to the population reduced the prevalence of inadequacy by at least half for most nutrients. Correction for energy deficits resulting from severe food insecurity contributed a mean additional 20% improvement in nutrient intakes. CONCLUSIONS: Food-insecure women would sustain substantive nutritional gains if they had greater access to their personal healthy food preferences and if the dietary compromises associated with severe food insecurity were abated. Increased resources to access such choices should be a priority.     

Comparison of biological collectors of airborne heavy metals near ferrochrome and steel works

The value of several biological monitors of the distribution of airborne Cr and Ni dust was studied in the vicinity of ferrochrome and stainless steel works. The following indigenous biomonitors were compared: the forest mosses Pleurozium schreberi and Hylocomium splendens, the epiphytic lichen Hypogymnia physodes, bark of Scots pine (Pinus silvestris), needle litter, earthworms (Dendrobaena octaedra) and moths (mainly Xylena vetusta). Results were compared and related to the heavy metal deposition estimated by the vertical snow sampling method. The representative sampling size at different pollution levels was investigated. In Cr it varied from 1 to 300 mg m^?2 a^?1. Of the biomonitors studied, the mosses showed most effective accumulation of heavy metals, their results having a clear relationship to the deposition and good replicability. The lichen gave almost as good results as the mosses. Both mosses and lichens collected heavy metals more effectively at low to moderate pollution loads than near the pollution source. The accumulation of heavy metals in bark was lower than in the mosses or lichen. The heavy metal content of earthworms indicated the degree of pollution well, but the replicability of the method was poor. The accumulation of heavy metals in moths was low.     

What do conservation biologists publish?

We provide an overview of publications from three prominent conservation journals (Biodiversity & Conservation, Biological Conservation and Conservation Biology) published in 2001 (n = 547 papers). We found a wide breadth of studies of different topics from different climates and habitats and across a range of spatial scales. Most studies were quantitative (89%) and used inferential statistics (63%). Research was biased towards vertebrates, forests, relatively pristine landscapes, and towards studies of single species and assemblages rather than communities or ecosystems. Despite assertions in the literature that conservation is synthetic, eclectic and multi-disciplinary, few studies were truly cross-disciplinary (13%). In addition, few studies investigated the loss of native vegetation (2%), or specifically studied introduced (4%) or non-threatened species (4%). 20% and 37% of studies had high relevance to policy and management, respectively. However, only 12.6% of studies actively went out to test or review conservation actions. Although many topics are covered in the literature, improvements are possible. We suggest: (1) broadening the number of habitats, taxonomic groups and scales studied and (2) providing closer and clearer links with other disciplines and research approaches, and with policy and management.     

水利工程建设中的水土流失及其防治措施

近年来,水利工程建设项目日益增多.在过去,由于片面强调水利工程主体的建设而忽视了水土保持工作,大部分水利工程存在不同程度的人为水土流失.根据调查资料,分析总结了水利工程建设中水土流失的原因,并提出了一般性防护措施.     

Indicators of biodiversity, what do they indicate? - Lessons for conservation of cryptogams in oak-rich forest

In the Nordic countries, sets of Indicator (Signal) species, predominantly cryptogams, have been used as one measure to find forest stands which may harbour Red List species. Such data could potentially also be used to prioritise among stands for protection as nature reserves. We studied if the number of Signal species indicates the number of Red List species in oak-rich mixed forest in south Sweden. We also explored if species richness of the investigated groups is correlated with the number of Red List or Signal species. In 25 stands, we surveyed epiphytic and epixylic bryophytes and lichens, ground-floor bryophytes, and wood-living fungi. We studied correlations for two datasets; (1) all forest species and (2) deciduous forest specialists. When relating the number of Signal species to the number of Red List species for each taxon and in total, a significant correlation was found for temperate deciduous forest lichens. The number of Signal species was further significantly correlated to total species richness for lichens (all forest species) and for wood-living fungi (both datasets). The number of Red List lichens was correlated to total lichen richness (deciduous forest species). Signal species seem not to be unequivocal in prioritising potential reserves among valuable oak-rich woodlands and surveys by Red List species experts may be needed. Signal species may be more useful for finding relatively valuable sites in a matrix of production forest. Moreover, Signal species seem to be useful surrogates for total cryptogam species richness.     

Response of aquatic vegetation to sedimentation downstream from river channelisation works in England and Wales

Measurements of aquatic vegetation at four sites of river channelisation works in south-central England are described and analysed. Physical factors determine the nature and extent of downstream deposition of sediment arising during construction. Depending on the depth of sediment, individual plant species may respond either by varying their rooting levels or by becoming smothered. Suspended sediment released was silt and did not abrade plant parts. Post-construction deposits were a short-term phenomenon, being washed out during flood events, thereby facilitating recovery of vegetation.     

Can stumps tell what people want: Pattern and preference of informal wood extraction in an urban forest of Nairobi, Kenya

Detailed patterns and preferences of informal wood extraction were investigated in an urban forest used by slum inhabitants of Nairobi, Kenya, as such information determines the sustainability of resource use. Instead of asking the people what they had secretly cut, a survey was conducted of the stumps and trees left in the forest to (i) evaluate how accessibility and patrolling affected spatial patterns of resource use, and to (ii) estimate a broad spectrum of species and species-specific size preferences. Both probability and size of cutting increased with better accessibility (represented by distance from the slum), and stump size exceeded that of living stem size around 1.7 km from the slum, which suggested magnified impact of tree cutting near the slum. Patrolling (represented by distance from ranger stations) had little effect in reducing the probability of cutting but was effective in reducing cut size. With the use of random effect models, a broad species preference spectrum (including less abundant and non-preferred species) was estimated, which indicated trends in vegetation change. Smaller stems were preferred for most species presumably used for domestic fuelwood, but major exploitation of large Brachylaena huillensis stems traded in the woodcarving industry was also revealed. Such detailed information on informal wood use can help forest managers to understand threats to the forests as well as the needs of local communities. This is a first step to redefining ‘acceptable’ resource use by the local community for their increased role and responsibility in sustainable forest management, especially when conventional controls of informal activities (i.e. exclusion and penalty) are not functioning well.     

Greenhouse evaluation of struvite and sludges from municipal wastewater treatment works as phosphorus sources for plants

Sewage sludge obtained by a conventional aerobic activated sludge process (CSS), P-rich sewage sludge from an enhanced biological P removal process (PRS), and struvite (MgNH 4PO 4 x 6H 2O) recovered from an anaerobic digester supernatant using a low-grade MgO byproduct from the calcination of natural magnesite as a Mg source (STR) were evaluated as P sources for plant growth. For this purpose, a greenhouse pot experiment was conducted using a P-deficient loamy sand soil and perennial ryegrass ( Lolium perenne L.) as the test crop. The P sources were applied at rates equivalent to 0, 9, 17, 26, 34, and 44 mg/kg P. Single superphosphate (SUP) was used as reference for comparison with the other P sources. The results obtained indicated that STR was as effective as SUP in increasing the dry matter yield and supplying P to ryegrass. Compared to SUP and STR, PRS and especially CSS exhibited less agronomic effectiveness as P sources, which may be attributed, at least partially, to greater soil P fixation because of the larger amount of Fe incorporated with these materials.     

Coastal dynamics and impact of coastal protection works on the Spurn Head spit (UK)

The erosion of the glacial tills along the Holderness Coast (eastern England) has released material which has led to the formation of a 4.5 km sand and gravel spit, Spurn Head, across the mouth of the Humber estuary. This paper examines the sedimentology and geomorphology of the spit and of the tidal flat behind it (Spurn Bight), and assesses the effects of coastal defences on the nearshore dynamics. A study of the coastal dynamics was carried out by analysing wind data and modelling wave shoaling and refraction at the estuary mouth, and on the tidal flat. The geomorphology and sedimentology of the beaches and the tidal flat were studied to assess the response of the spit system to different weather conditions.The results show that only 6% of the longshore drift produced by cliff erosion in Holderness is transported along Spurn Head, mainly by waves from the north and the north-east. This drift is stored in an area of sand and gravel banks at the tip. Medium-size sand is carried around the tip by south-easterly waves, leading to the formation of a small area of tidal sand waves. Waves from the southwest, which originate within the estuary, spread the sand over the tidal flat, but are not able to carry it towards the most northern inner part of the spit. Coastal defences built along the spit have slowed its rate of landward migration and prevented overwash processes. The defences have not been maintained for the last 30 years so that the spit is now likely to be breached in the winter months whenever surge conditions exist.