Population Declines and Range Contractions among Lowland Farmland Birds in Britain

We used extensive atlas and census data to assess trends in the distribution and population levels of birds on lowland farmland in Britain between the late 1960s and early 1990s. Many species of farmland birds have become less widespread or have declined in numbers, or both, but few have become more wide-spread or have increased. Of the 28 species classified as farmland birds the distributions of 24 contracted between 1970 and 1990. Of the 18 farmland species for which it was possible to assess population change, 15 were less abundant in 1990 than in 1970. Seven of the species were estimated to have undergone population decreases of at least 50%. Farmland species showing the largest population declines tended also to show substantial range contractions. Farmland species underwent an appreciably larger contraction of distribution than species associated with any other habitat. Furthermore, farmland species tended to decrease in abundance, whereas woodland species tended to increase. Population declines among farmland birds became evident in the mid- to late 1970s, a period when several fundamental changes were taking place in British agricultural practices. These included a great reduction in the spring sowing of cereals, a simplification of crop rotations, increased use of chemical pesticides and inorganic fertilizers, and more-intensive grassland management. We suggest that the declines of farmland bird species have been caused or aggravated by this pervasive intensification of agriculture. Existing research on declining farmland birds, however, indicates that there is no single mechanism underlying the population changes. We identify priorities for research, focusing mainly on relationships between bird populations and agricultural practices, but we also recognize a need for a better understanding of the role of predation.     

Vertical migration and feeding of Euphausia lucens at two 72 h stations in the southern Benguela upwelling region

Diel vertical migration of Euphausia lucens was studied over 72 h at an inshore and at a midshelf station in the southern Benguela upwelling region during February 1991, using stratified net tows and by employing gut contents (chlorophyll/copepods) as tracers of historic position. Soon after population arrival in the surface layers of the inshore station (abundant chlorophyll), E. lucens became dispersed and redistributed over depth. This was accompanied by a rapid downward transfer of surface-collected chlorophyll. A continuous exchange of individuals between deep and shallow water was subsequently inferred, prior to population descent at around dawn. These data are in agreement with the hunger-satiation hypothesis and were shared by individuals at the midshelf station (low chlorophyll). Interestingly, the major part of the E. lucens population at the midshelf station was confined to deep water throughout 24 h. While this conflicts with the hunger-satiation hypothesis, such behaviour is required to both ensure population maintenance and avoid surface predation within the Benguela region. Although the examination of some recent literature suggests that asynchronous, hunger-satiation behaviours may be common amongst euphausiids in single-species assemblages, responses to the food environment may be constrained by other factors.     

Pelagic biogeography of the South Atlantic Ocean

The biogeography of the South Atlantic was investigated using presence/absence data for euphausiids. Records were taken from recent and historic, as well as published and unpublished data sets. The resulting biogeography is the most complete to date and can be usefully compared with the biogeochemical provinces for the region. A total of six biogeographic provinces were identified from similarity analyses of the 246 five-degree grid squares. These correspond to Antarctic, sub-Antarctic, cold temperate, warm temperate (subtropical) and tropical waters, as well as the Agulhas Current. Congruence with the biogeochemistry of the region is good in the south and emphasises the important determinate role of temperature. However, the biogeography fails to identify coastal and tropical biogeochemical provinces. This can be attributed to the fact that while adjoining areas may share many species in common, their assemblages differ in their quantitative composition. This serves to emphasise differences in provincial functioning. Received: 28 May 1997 / Accepted: 15 July 1997     

Introducing a common taxonomy to support learning from failure in conservation

Although some sectors have made significant progress in learning from failure, there is currently limited consensus on how a similar transition could best be achieved in conservation and what is required to facilitate this. One of the key enabling conditions for other sectors is a widely accepted and standardized classification system for identifying and analyzing root causes of failure. We devised a comprehensive taxonomy of root causes of failure affecting conservation projects. To develop this, we solicited examples of real-life conservation efforts that were deemed to have failed in some way, identified their underlying root causes of failure, and used these to develop a generic, 3-tier taxonomy of the ways in which projects fail, at the top of which are 6 overarching cause categories that are further divided into midlevel cause categories and specific root causes. We tested the taxonomy by asking conservation practitioners to use it to classify the causes of failure for conservation efforts they had been involved in. No significant gaps or redundancies were identified during this testing phase. We then analyzed the frequency that particular root causes were encountered by projects within this test sample, which suggested that some root causes were more likely to be encountered than others and that a small number of root causes were more likely to be encountered by projects implementing particular types of conservation action. Our taxonomy could be used to improve identification, analysis, and subsequent learning from failed conservation efforts, address some of the barriers that currently limit the ability of conservation practitioners to learn from failure, and contribute to establishing an effective culture of learning from failure within conservation.     

Human rights and proactive displacement: determining the appropriate balance between the duty to protect and the right to remain

The proactive displacement by public authorities of populations from areas perceived to be exposed to a high risk of disaster presents complex human rights challenges. Provided that no ulterior motive is at play, the use of compulsory evacuations and relocations as policy responses to such risk is mandated by the duty to protect the right to life. However, proactive displacement in the interest of saving lives can be problematic as such measures can lead to the limitation of other human rights, resulting in an intricate assessment of whether compulsory evacuation or permanent relocation is proportional in any given circumstance. Such an analysis demands critical attention by public authorities to the perception of the disaster risk in question and problematises claims to objectivity of official risk assessments. Furthermore, it poses the question as to whether measures designed to address the disaster risk in question that are less intrusive than relocation may be available to public authorities.     

Physicochemical variations in atmospheric aerosols recorded at sea onboard the Atlantic–Mediterranean 2008 Scholar Ship cruise (Part II): Natural versus anthropogenic influences revealed by PM10 trace element geochemistry

The geochemistry of PM₁₀ filter samples collected at sea during the Scholar Ship Atlantic–Mediterranean 2008 research cruise reveals a constantly changing compositional mix of pollutants into the marine atmosphere. Source apportionment modelling using Positive Matrix Factorization identifies North African desert dust, sea spray, secondary inorganic aerosols, metalliferous carbon, and V–Ni-bearing combustion particles as the main PM₁₀ factors/sources. The least contaminated samples show an upper continental crust composition (UCC)-normalised geochemistry influenced by seawater chemistry, with marked depletions in Rb, Th and the lighter lanthanoid elements, whereas the arrival of desert dust intrusions imposes a more upper crustal signature enriched in “geological” elements such as Si, Al, Ti, Rb, Li and Sc. Superimposed on these natural background aerosol loadings are anthropogenic metal aerosols (e.g. Cu, Zn, Pb, V, and Mn) which allow identification of pollution sources such as fossil fuel combustion, biomass burning, metalliferous industries, and urban–industrial ports. A particularly sensitive tracer is La/Ce, which rises in response to contamination from coastal FCC oil refineries. The Scholar Ship database allows us to recognise seaborne pollution sourced from NW Africa, the Cape Verde and Canary islands, and European cities and industrial complexes, plumes which in extreme cases can produce a downwind deterioration in marine air quality comparable to that seen in many cities, and can persist hundreds of kilometres from land.     

Water purification systems: a comparative analysis based on the occurrence of disinfection by-products

Trihalomethanes (THMs) are halogenated hydrocarbons, and are by-products of the chlorination of drinking water. Most THMs are formed in drinking water when chlorine reacts with naturally occurring organic substances such as decomposing plant and animal materials. Risks for certain types of cancer are now being correlated with the presence of disinfection by-products (DBPs). The present research uses gas chromatography to analyze the presence and levels of THMs in drinking water samples from a variety of sources. These include (1) municipal drinking water from two south Florida counties; (2) two brands of bottled water; (3) untreated residential well water; and (4) municipal tap water passed through additional water purification systems. The results are summarized in a tabular format, and the compliance of each water with existing US EPA-mandated standards is examined. General conclusions from this study are that all the waters tested complied with federal regulations regarding THM levels, properly functioning home filtration units may be quite effective in further reducing DBP concentrations and, as expected, non-chlorinated waters such as bottled water and residential well water contain lower THM levels.     

Zoogeography and diversity of euphausiids around southern Africa

Published and unpublished records of euphausiid distributions around southern Africa are examined for zoogeographic pattern and the results compared with patterns generated from intertidal data sets. Two basic groups of euphausiids are discerned from cluster analysis, corresponding to neritic and oceanic assemblages. Superimposed upon these are Indian Ocean (Agulhas Current) and Atlantic Ocean (Benguela Current) groups. Patterns of diversity and zoogeography generally conform to the large-scale hydrological features in the area. Diversity is higher in the oceanic than in neritic regions. Maximum diversity is recorded off Cape Point, where Indian, Atlantic and southern Ocean waters interact. Diversity is otherwise higher along the east coast, and particularly low in the nearshore waters of the Benguela Current. While particular species of euphausiids can be associated with Agulhas Current and Angola Current waters, westcoast communities lack any distinctive species, and this is discussed. Although the patterns of zoogeography observed for euphausiids are generally similar to those observed for rocky shore communities, there are clear differences between them that reflect their respective habitats and the influence that large-scale water movement has on each.     

Controls on hourly variations in urban background air pollutant concentrations

Average 21st century concentrations of urban air pollutants linked to cardiorespiratory disease are not declining, and commonly exceed legal limits. Even below such limits, health effects are being observed and may be related to transient daytime peaks in pollutant concentrations. With this in mind, we analyse >52,000 hourly urban background readings of PM₁₀ and pollutant gases throughout 2007 at a European town with legal annual average concentrations of common pollutants, but with a documented air pollution-related cardiorespiratory health problem, and demonstrate the hourly variations in PM₁₀, SO₂, NO_x, CO and O₃. Back-trajectory analysis was applied to track the arrival of exotic PM₁₀ intrusions, the main controls on air pollutants were identified, and the typical hourly pattern on ambient concentrations during 2007 was profiled. Emphasis was placed on “worst case” data (>90th percentile), when health effects are likely to be greatest. The data show marked daytime variations in pollutants result from rush-hour traffic-related pollution spikes, midday industrial SO₂ maxima, and afternoon O₃ peaks. African dust intrusions enhance PM₁₀ levels at whatever hour, whereas European PM incursions produce pronounced evening peaks due to their transport direction (across an industrial traffic corridor). Transient peak profiling moves us closer to the reality of personal outdoor exposure to inhalable pollutants in a given urban area. We argue that such an approach to monitoring data potentially offers more to air pollution health effect studies than using only 24 h or annual averages.