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Control of sandstorms in Inner Mongolia, China
- MEIZHEN LIU, GAOMING JIANG, LINGHAO LI, YONGGENG LI, LEIMING GAO, SHULI NIU
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- 13 April 2005, pp. 269-273
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About one third of the world's land surface is covered with arid and semi-arid areas. It is predicted that global warming will increase desertification by 17% before 2050. At present, desertification is making approximately 12 million hectares every year useless for cultivation and grazing worldwide. Over 250 million people and one third of the earth's land surface are directly threatened by desertification (Diallo 2003). China is one of several countries severely affected by desertification; almost 90% of natural grassland has been affected to differing degrees (Lu & Yang 2001; State Environmental Protection Administration of the People's Republic of China 2002). The land desertification rate in China was 1560 km2 yr−1 in the 1970s. This rate had increased to 2100 km2 yr−1 by the 1980s, and was 2460 km2 yr−1 by 1995 and 3436 km2 yr−1 in 1999 (Zhu et al. 1999). Areas that have shown increased desertification are derived from degraded grassland or cultivated land (Zhang & Cheng 2001). One very serious direct consequence of grassland degradation is thought to be the frequent occurrence of sandstorms. Whereas China was hit by almost 70 sandstorms over the past century (Qing 2002), with an average frequency of one sandstorm every three years in the 1940s, this had increased to one every two years by the 1960s. By the 1990s, the sandstorms in north China took place several times a year and this increased further to 12 in 2000 and 18 in 2001 (Jiang 2002a). The frequency of sandstorms in north China appears to be a direct consequence of grassland degradation. Taking Hunshandak Sandland in Inner Mongolia as an example (Fig. 1), the proportion of sand dunes that are shifting rose from 2.3% in the 1950s to 50% in the 1990s, while available grasslands declined by some 40% between the 1950s and the 1990s. The economic cost of these sandstorms has prompted the Chinese government to commit substantial funds to meet this loss, but the degradation is ongoing in the area and the living standards of local people are still low (Liu et al. 2003). It is opportune to adjust strategies to reach two objectives simultaneously, namely to restore the degraded grassland, and improve the living conditions of local people. To illustrate this, we focus on Zhenglan Banner (county), which is representative of the whole Hunshandak Sandland in terms of climate (Ma et al. 1998), economy and ecology (Fig. 1). Zhenglan Banner has a total area of 100 600 km2, a human population of 78 730 and stock raising is the dominant industry, the average income per person per year being US$ 225 (Bureau of Stock Raising in Zhenglan Banner 2002).
Integrative ecological restoration and the involvement of local communities in the Tehuacán-Cuicatlán Valley, Mexico
- SHIVCHARN S. DHILLION, MARIEL AGUILAR-STØEN, SARA LUCIA CAMARGO-RICALDE
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- 02 April 2004, pp. 1-3
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Restoration ecology is a science focusing on using ecological principles to improve ecosystems degraded usually through habitat destruction (Bradshaw & Chadwik 1980, Handel et al. 1994). Successful ecological restoration depends on negotiation and understanding of different stakeholders, including the daily users of the resources, government institutions that will regulate resource use and the research community working in the area.
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A systematic approach for selecting focal species for conservation in the forests of Nova Scotia and Maine
- KAREN BEAZLEY, NATHAN CARDINAL
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- 27 July 2004, pp. 91-101
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Focal species are a critical component of conservation planning, along with representation of ecosystems, special elements and ecologically sustainable management. They warrant conservation attention because they are functionally important, wide-ranging or space-demanding, habitat-quality indicators, ‘flagship’, and/or vulnerable or special populations. A delphi survey matrix-based approach, involving regional experts in the selection of potential focal species, was applied in Nova Scotia, Canada and Maine, USA. Matrices with native species on one axis and selection characteristics on the other axis were used to summarize expert knowledge and judgment. Characteristics were related to biological traits and habitat requirements that make some species more vulnerable than others in human-modified landscapes. In Nova Scotia and Maine, 19 and 11 experts, respectively, completed the matrices, which were subsequently numerically assessed. Species with the highest scores were identified as potential focal species, including wolf, cougar, lynx, river otter, eastern pipistrelle, wood turtle, four-toed salamander, golden eagle and Atlantic salmon. Concerns remain around the lack of representation of some classes of species, subjectivity in selecting and weighting characteristics, and the relative nature of assessing species against the characteristics. Accordingly, potential focal species should be subject to verification through more rigorous and quantitative analysis and monitoring. Nonetheless, if applied with care, the matrix-based approach can provide a relatively systematic and effective way of engaging regional experts in focal species selection.
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Traditional knowledge and satellite tracking as complementary approaches to ecological understanding
- HENRY P. HUNTINGTON, ROBERT S. SUYDAM, DANIEL H. ROSENBERG
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- 11 January 2005, pp. 177-180
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The integration or co-application of traditional knowledge and scientific knowledge has been the subject of considerable research and discussion (see Johannes 1981; Johnson 1992; Stevenson 1996; McDonald et al. 1997; Huntington et al. 1999, 2002), with emphasis on various specific topics including environmental management and conservation (see Freeman & Carbyn 1988; Ferguson & Messier 1997; Ford & Martinez 2000; Usher 2000; Albert 2001). In most cases, examples of successful integration compare traditional and scientific observations at similar spatial scales to increase confidence in understanding or to fill gaps that appear from either perspective. We present a different approach to integration, emphasizing complementarity rather than concordance in spatial perspective, using two migratory species as examples.
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The Galápagos sea cucumber fishery: management improves as stocks decline
- S.A. SHEPHERD, P. MARTINEZ, M.V. TORAL-GRANDA, G.J. EDGAR
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- 27 July 2004, pp. 102-110
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The Galápagos Islands, a world heritage region for the protection of the unique terrestrial and marine wildlife, are also home to a small human population, dependent on fisheries. There was a lucrative sea-cucumber (Stichopus fuscus) fishery in the islands, which began in 1992. After a rapid expansion in the Galápagos archipelago, the fishery has declined and now persists predominantly around the western islands. Initially, the fishery was largely illegal and uncontrollable. Subsequently, a co-management framework developed, with fisher participation. Gradually enforcement improved, apparent corruption declined, and research capacity increased. Although stock abundance surveys have been carried out annually since 1993, the paucity of background biological and fishery information does not allow rigorous stock assessment. The achievements of co-management through the participation of fishers in research and management have been: an acceptance of management controls on numbers of fishers and quotas, a reduction in conflict and increased co-operation. Persistent problems have been: weak enforcement capacity, limited funds for patrolling and research, corruption and declining stock abundance. Proposed application of precautionary principles to management, including a range of fishery indicators, may save the fishery from collapse. The principles are applicable to many other data-poor fisheries globally.
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Is Viagra a viable conservation tool? Response to Hoover, 2003
- WILLIAM VON HIPPEL, FRANK A. VON HIPPEL
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- 02 April 2004, pp. 4-6
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In 1998, we (von Hippel & von Hippel 1998) suggested that the advent of Viagra might take some of the market pressure off a variety of threatened species used to treat erectile dysfunction (ED) in traditional Chinese medicine (TCM). In 2002, we (von Hippel & von Hippel 2002) followed up this initial suggestion by providing a more complete analysis of the species that might benefit if TCM consumers switched to Viagra, and we also provided preliminary evidence that the harvest of a few species used in TCM may have already declined due to the availability of Viagra.
How useful are urban island ecosystems for defining invader patterns?
- PHILIPPE CLERGEAU, SOLÈNE CROCI, JUKKA JOKIMÄKI
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- 11 January 2005, pp. 181-184
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Biological invasions are pervasive, alter ecosystem sustainability, and can reduce native biological diversity (Vitousek et al. 1996). Ecologists are scrambling to predict where and when new invaders may strike (Lodge 1993; Fagan et al. 2002). Urbanization has created a number of new ecological niches which, after remaining empty for some time, are increasingly being colonized or invaded by vertebrates (Erz 1966). One of the major disputes in evolutionary biology concerns the rate at which species evolve to occupy new niches (Diamond 1986). How quickly are animals adapting to these new habitats and what makes them successful colonists?
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Effectiveness of a confinement strategy for reducing campsite impacts in Shenandoah National Park
- SCOTT E. REID, JEFFREY L. MARION
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- 13 April 2005, pp. 274-282
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The expansion and proliferation of backcountry campsites is a persistent problem in many parks and protected areas. Shenandoah National Park (SNP) has one of the highest backcountry overnight use densities in the USA national parks system. SNP managers implemented a multi-option backcountry camping policy in 2000 that included camping containment with established campsites. These actions were intended to reduce the number of campsites and the area of camping disturbance at each site. This paper describes a longitudinal adaptive management assessment of the new campsite policies, applying quantitative measures of campsite conditions to evaluate the efficacy of management interventions. Physical campsite measurements combined with qualitative visitor interviews indicated SNP had successfully reduced the number of campsites and aggregate measures of camping-related disturbance in the Park, while minimizing the use of regulations, site facilities and staff resources. Implications for managers of other protected areas are that an established site camping policy can minimize camping disturbance, including the number and size of campsites, provided managers can sustain rehabilitation efforts to close and restore unneeded campsites. Experiential attributes, such as the potential for solitude, can also be manipulated through control over the selection of established campsites. Integrating resource and social science methods also provided a more holistic perspective on management policy assessments. Adaptive management research provided a timely evaluation of management success while facilitating effective modifications in response to unforeseen challenges. Conclusions regarding the effectiveness of a visitor impact containment strategy involving an established site camping option are offered.
Distribution, diversity, and conservation of coral reefs and coral communities in the largest marine protected area of Pacific Panama (Coiba Island)
- HECTOR M. GUZMAN, CARLOS A. GUEVARA, ODALISCA BREEDY
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- 27 July 2004, pp. 111-121
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Sampling scale and lack of attention to taxa other than scleractinian corals have limited the capacity to protect coral reefs and coral communities in Pacific Panama. The distribution of coral habitats (live coral cover) and their species richness in the largest marine protected area of Panama, the Coiba National Park (270 125 ha), is described using quadrat transects and manta tows. The species richness of scleractinian corals and octocorals was lower in coral reefs than in coral communities, and a close relationship between richness and live coral cover was observed only in coral communities. The distribution of high live coral cover in coral communities overlapped with areas of high coral species richness. Average live coral cover in communities was 64%, compared to 28% in reefs, whereas algae cover was 30% and 49%, respectively. Twenty-two coral and 34 octocoral species were observed, many only now detected in Panama as endemic or new species. Analysis of satellite imagery showed 80% of terrestrial habitats were mostly primary forest, and coral reefs and coral communities covered 1700 ha, about 2% of marine habitats. Shallow marine environments (< 20 m) had up to 60% calcareous red algae cover (rhodolite beds). Based on the distribution of live coral cover and species richness, three conservation units were identified as priority, with the southern and northernmost sides of the marine protected area as the most significant. These three areas encompass most of the rare and endemic species or populations, as well as species previously regarded as endangered.
The effect of human activities on migrant shorebirds: successful adaptive management
- JOANNA BURGER, CHRISTIAN JEITNER, KATHLEEN CLARK, LAWRENCE J. NILES
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- 13 April 2005, pp. 283-288
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The effect of human disturbance on migrant birds is a conservation issue of international importance, as is determining if disruption has long-term population effects. Disruptions can occur during migration, wintering, breeding and foraging. Thousands of shorebirds migrate through Delaware Bay (Atlantic Coast of North America) in a four-week period each spring; this is the largest concentration of shorebirds in the continental USA. Ecotourists come to see them, creating the potential for disruption. Data available on shorebird/human interactions at a migratory stopover over a 20-year period were used to describe the interactions of shorebirds and people from 1982–2002 and examine trends in human disruptions and shorebird behaviour during this time. The rate of disruptions caused by people increased during the 1980s, declined slightly by the early 1990s, and declined sharply by 2002. The decline in human activity along the beach was directly related to the conservation efforts of the New Jersey Endangered and Nongame Species Program, New Jersey Audubon, and others interested in preserving the shorebirds. In the 1980s, birdwatchers concentrated on the beaches on which it was easy to walk and which had the highest shorebird counts, because there were no restrictions on human behaviour. During this time, the average disturbance duration was over 10 min, regardless of the type of intruder, and shorebirds were often disrupted for over 40 min hr−1. Even though the number of disruptions declined over the study period, the percentage of shorebirds that flew away (and did not return within 10 min) did not change during the 1980s, and increased in 2002. The average time that shorebirds were disrupted per hour by people declined during this period (mainly because there were fewer people on the beaches). The Endangered and Nongame Species Program placed signs on shorebird foraging beaches, restricted access, built viewing platforms to contain ecotourists, and eventually patrolled key beaches and issued summonses for infractions. These activities were so effective that only one bird watcher disturbed the birds in 2002. Education was also vital to encouraging local residents not to walk or fish along these beaches during the spring migratory stopover, and to keep their dogs on a leash. These data support the importance of actions on the part of state agencies and conservation organizations to limit disruptions to foraging shorebirds during critical migratory stopovers, a problem faced by shorebirds in many temperate regions of the world.
Accelerating deforestation in Brazilian Amazonia: towards answering open questions
- PHILIP M. FEARNSIDE, REINALDO IMBROZIO BARBOSA
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- 02 April 2004, pp. 7-10
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The annual rate of deforestation in Brazilian Amazonia jumped by an estimated 40% between 2001 and 2002. This increase is in addition to a 15% upward revision by the Brazilian government of the estimated rate for 2001. Examination of the data underlying these estimates and comparisons with other measurements indicates that important questions remain unanswered, especially in the state of Mato Grosso, where assessment of the effectiveness of a deforestation licensing and control programme is critical to future efforts to contain forest destruction. The increase in deforestation rate in Mato Grosso in 2002 (23%) was less than half the increase in the remainder of Brazilian Amazonia (55%), indicating that the state government's deforestation control programme may have had some effect.
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Incorporating ecological perspectives in European groundwater management policy
- DAN L. DANIELOPOL, JANINE GIBERT, CHRISTIAN GRIEBLER, AMARA GUNATILAKA, HANS JÜRGEN HAHN, GIUSEPPE MESSANA, JOS NOTENBOOM, BORIS SKET
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- 11 January 2005, pp. 185-189
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Implementation of the European Union (EU) Water Framework Directive (WFD 2000) and its planned supplement ‘Directive on the Protection of Groundwater against Pollution’ (EU GWD [European Union Groundwater Directive] 2003) demands an initial characterization of all groundwater bodies by national and regional authorities. The main criteria considered in the Directives to define the groundwater (GW) status are quality (chemical) and quantity, but there is the obvious omission of ecological perspective in these. A directive for a comprehensive policy dealing with GW protection at the level of the EU is a prerequisite for human welfare. Additionally, recognition of GW-dependent ecosystems (GDEs) in the EU is equally important for their sustainable management. GW management and policy should recognize the ecological functions of GW and their interactions with GDEs. As they can stretch across national and regional boundaries, political recognition of their importance and the necessity for ecological consistency of management plans have to be emphasized. During the last three decades, a number of researchers have focused their attention on the dynamics and functioning of GW ecosystems and this work could serve as a basis for identifying impacts of changes in key attributes of GDEs. Detailed aspects of GW ecosystems have been comprehensively dealt with (Gibert et al. 1994; Wilkens et al. 2000; Griebler et al. 2001; Danielopol et al. 2003). Changes in key attributes of GW ecosystems have had consequences for the environment in the EU and USA (Klijn & Witte 1999; Winter 1999; Sophocleous 2002; Winter et al. 2003).
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Colonization and tropical deforestation in the Sierra Santa Marta, Southern Mexico
- LETICIA DURAND, ELENA LAZOS
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- 02 April 2004, pp. 11-21
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Understanding patterns of tropical deforestation is a crucial issue for Mexico, a country that has lost more than 95% of its original rainforest cover. This paper examines the causes of accelerated deforestation in the Sierra Santa Marta, Veracruz, Mexico, by looking at settlement history and the evolution of productive schemes in the villages of Venustiano Carranza and Magallanes. Both settlements were founded in the 1960s, after the government donated land to landless peasants. Conversion of forests into pastures, after several agricultural enterprises failed, resulted in more than 80% of the original tropical rainforests being removed in both communities between 1960 and 1998. The process of deforestation in the villages differed from models proposed for the Amazon and Central America, in which deforestation responded to capital-intensive efforts to open up the tropical frontier. In the villages, transformation of forests into pastures was, from the beginning, a smallholder phenomenon. Misguided policies and institutional malfunctions appeared to direct households toward deforestation. Nevertheless, environmental deterioration could not only be explained by external causes. Inside the communities, demographic pressure over land, the modification of traditional land tenure systems and the cultural adoption of cattle as a way to overcome poverty were significant factors in the relationship between colonization and forest clearance. Deforestation at Venustiano Carranza and Magallanes cannot be considered an ecologically destructive practice performed by peasants. In fact, the process reflects not only a lack of environmental awareness in national development policies, but also the intricate interaction of ecological, cultural, social and economical variables.
Dose-response relationships of harlequin duck behaviour to noise from low-level military jet over-flights in central Labrador
- R. IAN GOUDIE, IAN L. JONES
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- 13 April 2005, pp. 289-298
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Concern for the lack of field studies on the effects of low-level military jet over-flights on wildlife resulted in directed research in the Military Training Area of Labrador, 1999–2002. At Fig River, a tributary of the Lower Churchill River, a before-after-control-impact (BACI) study design quantified effects of aircraft over-flights on behaviour of individual harlequin ducks (Histrionicus histrionicus) in the 130 000 km2 Military Training Area of central Labrador. Noise generated from low-level passes (30–100 m above ground level) by military jets was sudden in onset and high in amplitude (>100 dBA), substantially above background sound levels both at Fig Lake outlet (40–50 dBA) and rapid sections of Fig River (60–70 dBA). Harlequin ducks reacted to noise from military jets with alert behaviour, showing a positive dose-response that especially intensified when noise exceeded 80 dBA. Residual effects, in other words, deviations from normal behaviour patterns after initial responses, were decreased courtship behaviour for up to 1.5 h after, and increased agonistic behaviour for up to 2 h after military jet over-flights. Direct behavioural responses to military jet over-flights were of short duration (generally <1 min), and were unlikely to affect critical behaviours such as feeding and resting in the overall time-activity budgets of breeding pairs. However, the presence of residual effects on behaviour implied whole-body stress responses that were potentially more serious; these require further study because they are potentially more detrimental than immediate responses, and may not be detected in studies that focus on readily observed overt responses. A dose-response curve relating particular behaviours of harlequin ducks to associated noise of over-flights could be a valuable conservation tool for the research and mitigation of environmental impacts of aircraft and other noise.
Attitudes towards fishery and conservation of the Saimaa ringed seal in Lake Pihlajavesi, Finland
- MIKA TONDER, JUHA JURVELIUS
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- 27 July 2004, pp. 122-129
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The Saimaa ringed seal (Phoca hispida saimensis) is the only endemic mammal in Finland. At present the total population size of this subspecies is c. 250 individuals. Because the seal feeds on fish, and because of its value particularly as a source of meat, oil and leather, hunting was allowed until 1955. Conservation of the seal and some of its lairing areas by means of fishing restrictions requires the adoption of new attitudes. Semi-structured interviews elucidated the basis of conflicts concerning protection of the Saimaa ringed seal and fishing in Lake Pihlajavesi, Finland, where one of the most viable populations of the seal lives. Socio-economic position largely determined personal attitudes towards conservation; local landowners felt that their use of natural resources was restricted, while summer cottage owners wanted strict conservation. Commercial fishers considered the protection of the ringed seal unnecessary and a waste of money. Conservation biologists believed that the proposed actions were necessary to reduce the risk of extinction. Attitudes were also widely influenced by culture and social backgrounds. Those influenced by the traditional Finnish peasant/nature relationship had a different vision of nature from the conservationists who were influenced by modern science. Questions raised by the protection of the Saimaa ringed seal form an example of transition of an environmental conflict to larger-scale criticism of ongoing structural transformation in society. It is obvious that if nature conservation requires the approval of all social groups, it needs a change of authoritarian measures and acceptance of local knowledge, which should be used alongside scientific knowledge in management. Nature conservation policy led by specialists and authorities could be seen as widening the gap between urban and rural areas.
Can methods applied in medicine be used to summarize and disseminate conservation research?
- IOAN FAZEY, JANET G. SALISBURY, DAVID B. LINDENMAYER, JOHN MAINDONALD, ROBERT DOUGLAS
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- 11 January 2005, pp. 190-198
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To ensure that the best scientific evidence is available to guide conservation action, effective mechanisms for communicating the results of research are necessary. In medicine, an evidence-based approach assists doctors in applying scientific evidence when treating patients. The approach has required the development of new methods for systematically reviewing research, and has led to the establishment of independent organizations to disseminate the conclusions of reviews. (1) Such methods could help bridge gaps between researchers and practitioners of environmental conservation. In medicine, systematic reviews place strong emphasis on reviewing experimental clinical trials that meet strict standards. Although experimental studies are much less common in conservation, many of the components of systematic reviews that reduce the biases when identifying, selecting and appraising relevant studies could still be applied effectively. Other methods already applied in medicine for the review of non-experimental studies will therefore be required in conservation. (2) Using systematic reviews and an evidence-based approach will only be one tool of many to reduce uncertainty when making conservation-related decisions. Nevertheless an evidence-based approach does complement other approaches (for example adaptive management), and could facilitate the use of the best available research in environmental management. (3) In medicine, the Cochrane Collaboration was established as an independent organization to guide the production and dissemination of systematic reviews. It has provided many benefits that could apply to conservation, including a forum for producing and disseminating reviews with emphasis on the requirements of practitioners, and a forum for feedback between researchers and practitioners and improved access to the primary research. Without the Cochrane Collaboration, many of the improvements in research communication that have occurred in medicine over the last decade would not have been possible.
Social representations and environmental education with a women's group in Manaus, Amazonas-Brazil
- CHRISTINE STOREY, HAYDÉE TORRES DE OLIVEIRA
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- 13 April 2005, pp. 299-308
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Since the 1970s, it has been acknowledged that environmental education has an essential role to play in fostering environmental interrelations to promote sustainable societies, however, the theoretical and practical debates within environmental education are ongoing. There is an argument that divergent understandings of the environment need to be interpreted if interventions that are participatory and accommodate participants' environmental frameworks are to be planned. Research was carried out to verify whether the theory of social representations could assist environmental educators in interpreting participants' lifestyles and perceived needs. Accordingly, data were collected on environmental social representations within a group of 10 urban women from Manaus, Amazonas, Brazil. The objective was to understand the impact of such representations on the women's environmental awareness and assess the applicability of such data to planning environmental education interventions. The women's social representations were interpreted as being directed by five mediators, namely cultural heritage, identity, the media, religion and situation, which influenced their environmental practices and understandings. The interpretation process also illustrated contradictions in identities and situations that impacted on the women's environmental awareness. Interpretation of social representations offers valuable information about participants' conceptual frameworks and indicators of themes appropriate to planning educational interventions.
Changes in structure and cover of a common property pine forest in Guatemala, 1954–1996
- CURTIS D. HOLDER
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- 02 April 2004, pp. 22-29
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Concern about increasing rates of deforestation of tropical forests has resulted in investigations into the viability of local land-use practices and communal forms of governance. The majority of people in Guatemala live in regions where primary forests are absent. Several secondary forests in the highly populated highlands of Guatemala are communally managed forests, and people depend on forest products from these secondary forests for their livelihood. This study examines changes in forest structure and coverage of a native Pinus oocarpa Schiede communally managed forest in San Jose La Arada, Chiquimula in eastern Guatemala from 1954–1996. The pine forest is a municipal-communal property. The municipality has title to the land, however the forests are communal property. Neither forest committees in the villages nor municipal government regulations establish communal management of the pine forest; instead there are customary rules in the villages that guide forest extraction. People from the surrounding villages extract fuelwood, ocote (resin-rich wood harvested from the tree trunk and used for kindling) and timber from the pine forest. The P. oocarpa forest is situated in a seasonally dry region with nutrient-poor and highly eroded soils. Aerial photographs from 1954 and 1987 were compared to estimated changes in forest cover. Changes in forest structure are based on data collected from stand inventories conducted in 1987 and 1996. The pine forest was reduced in area by 14.4%, from 12.39 km2 in 1954 to 10.61 km2 in 1987. Additionally, stand density and basal area were reduced by 12% and 41%, respectively, from 1987–1996. Fuelwood and timber for domestic use were not extracted at a sustainable rate between 1954 and 1996 from the communally managed pine forest in this study. A sustainable-use management plan, in which all villages surrounding the forest participate, is recommended to provide future forest products for the villages.
Archaeology, biology and conservation on islands in the Gulf of California
- THOMAS BOWEN
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- 11 January 2005, pp. 199-206
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Urgent threats to the Gulf of California ecosystem from modern human activity obscure the fact that humans have interacted with native plants and animals for millennia. Archaeological and historical evidence suggests that indigenous peoples occupied both sides of the Gulf some 13 000 calendar years ago and that they eventually inhabited six major islands and visited most smaller ones. Biologists have increasingly realized that these peoples probably played a role in shaping island biotic communities extant today. How much of a role is unknown, but the best places to find evidence may be archaeological sites, which often contain remains of plants and animals directly used by prehistoric peoples. The opportunity to investigate the interaction between early humans and island biota may be lost because modern island visitors endanger sites. Many people, whether boaters, ecotourists, government officials, scientists or artefact collectors, enjoy picking up artefacts. Small surface sites, with exposed remains, can be completely denuded in minutes. Visitors to small islands can obliterate entire archaeological records, thereby creating the illusion of pristine islands. This problem is bound to worsen as Mexico implements Escalera Náutica, a chain of marinas specifically intended to multiply manyfold the boating population. The Mexican government's management plan for Gulf islands, published in 2000, recognizes only a general need to manage cultural resources. Specific mechanisms for protecting sites should be developed. These should educate visitors about the importance of the archaeological record and the destructiveness of collecting. They should also provide adequate enforcement of Mexico's existing antiquities laws. Conserving the archaeological resources may be the best way of preserving biological data essential to island biogeographers and ecologists.
A review of the impacts of control operations against the red-billed quelea (Quelea quelea) on non-target organisms
- ANDREW N. MCWILLIAM, ROBERT A. CHEKE
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- 27 July 2004, pp. 130-137
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Spraying with the organophosphate fenthion has been the predominant means to control the red-billed quelea (Quelea quelea), a major bird pest throughout semi-arid regions of sub-Saharan Africa, for more than forty years. A review of known effects of fenthion and other control measures used against Q. quelea on non-target organisms, provides a basis for comparisons with any alternative chemical control agents. Birds of prey, owls and passerines have been commonly reported casualties of spraying with fenthion over land. Moreover, fenthion is known to have negative effects on aquatic invertebrates, in particular on populations of crustacea, which predicates against its use near water bodies. Non-target species may be affected directly by spraying, but predatory birds, scavenging birds and even mammals can be contaminated by secondary poisoning when they eat Quelea carcasses found up to 20 km or more from the primary control site. To avoid secondary poisoning, where possible quelea carcasses should be removed from a site after spraying. The use of explosions to kill roosting quelea birds has similar effects to those of fenthion in terrestrial habitats, killing non-target species including birds of prey and owls. Another control method, harvesting quelea as a source of protein, is benign and could contribute to local nutritional and economic needs. However harvesting is unlikely to reduce quelea populations substantially. Integrated pest management (IPM) approaches are recommended to minimize environmental damage, but until these are successfully adopted, standardized procedures for comparative assessments of the effects of quelea control are required.