It seems widely accepted that environmental conservation will develop in the right direction only through dialogue across disciplines that is well sourced and objectively argued. Yet most people seem to have different ideas about what constitutes interdisciplinarity and few if any have a clear idea as to how different disciplines should be effectively integrated in the context of conserving the environment. The Comments section of the journal provides a unique opportunity to explore more of this important ground. In effect, Environmental Conservation is aiming for the Comments section to become a regular feature in each issue. This is a new departure to address topical issues of general interest through brief essays that are intended to stimulate discussion. Comments may either challenge or augment the findings of previously published work (in this or other journals), present new interpretations or syntheses of current issues, or suggest new ideas and approaches to environmental conservation, policy and management.

Most environmental scientists care about the state of nature. They are concerned about loss of biodiversity, degradation of ecosystems services and threats to sustainability. Do such concerns and the values they reflect make an environmental scientist an environmentalist? Should they be environmentalists?

Navassa Island is a small uninhabited island, approximately 60 km west of the south-west tip of Haiti (18°24′N, 75°00′W). Haiti laid claim to the island in 1804, however the USA claimed it under the Guano Act of 1856 and recently placed it under jurisdiction of the US Fish and Wildlife Service (USFWS). Remoteness from USFWS administration in Puerto Rico and disputed sovereignty by Haiti make enforcement of management impractical. Artisanal fishers from Haiti have frequented Navassa over the past several decades. Given the lack of current land-based development and limited transient land-based activity (for example salting fish and gear construction), Navassa provides a case study where fishing is largely isolated as the dominant human impact on coastal resources.

The world's arid and semi-arid regions are severely affected by desertification. In China, wind erosion, water erosion, soil salinization and the freezing and melting processes have contributed to 2.64 million km2 of desertified land, covering 27.5% of the country's land surface (State Forestry Administration, Peoples' Republic of China 2005). Although climate change could be a reason for desertification, anthropogenic factors such as overgrazing and overcultivation also contribute to degradation in grassland areas (Millennium Ecosystem Assessment 2005; Zheng et al. 2006). The Chinese government has adopted afforestation as the main measure to control desertification. Major projects, including the ‘Three North Shelterbelt Programme’ (also known as the ‘Green Great Wall’) and the ‘Sandstorm Source Control Project around Beijing and Tianjin’, are necessary to shield northern and eastern agricultural ecosystems against sand and dust (Zhou 2002). However, these countermeasures require substantial effort and investment, and, in the semi-arid and arid regions of Inner Mongolia, newly planted trees have often died of drought, while tree planting could also be responsible for exhausting the precious groundwater resources of these regions (Jackson et al. 2005). Alternative and more practical ways of combating desertification by using multi-disciplinary approaches observing both social and ecological principles are required. The Hunshandake Sandy Land restoration demonstration project conducted by the Chinese Academy of Sciences was an attempt to restore desertified grassland mainly through natural processes, and requiring limited investment.

Minimizing the impact of invasive alien species (IAS) on islands and elsewhere requires researchers to provide cogent information on the environmental and socioeconomic consequences of IAS to the public and policy makers. Unfortunately, this information has not been readily available owing to a paucity of scientific research and the failure of the scientific community to make their findings readily available to decision makers. This review explores the vulnerability of islands to biological invasion, reports on environmental and socioeconomic impacts of IAS on islands and provides guidance and information on technical resources that can help minimize the effects of IAS in island ecosystems. This assessment is intended to provide a holistic perspective on island-IAS dynamics, enable biologists and social scientists to identify information gaps that warrant further research and serve as a primer for policy makers seeking to minimize the impact of IAS on island systems. Case studies have been selected to reflect the most scientifically-reliable information on the impacts of IAS on islands. Sufficient evidence has emerged to conclude that IAS are the most significant drivers of population declines and species extinctions in island ecosystems worldwide. Clearly, IAS can also have significant socioeconomic impacts directly (for example human health) and indirectly through their effects on ecosystem goods and services. These impacts are manifest at all ecological levels and affect the poorest, as well as richest, island nations. The measures needed to prevent and minimize the impacts of IAS on island ecosystems are generally known. However, many island nations and territories lack the scientific and technical information, infrastructure and human and financial resources necessary to adequately address the problems caused by IAS. Because every nation is an exporter and importer of goods and services, every nation is also a facilitator and victim of the invasion of alien species. Wealthy nations therefore need to help raise the capacity of island nations and territories to minimize the spread and impact of IAS.

Unofficial roads form dense networks in landscapes, generating a litany of negative ecological outcomes, but in frontier areas they are also instrumental in local livelihoods and community development. This trade-off poses dilemmas for the governance of unofficial roads. Unofficial road building in frontier areas of the Brazilian Amazon illustrates the challenges of ‘road governance.’ Both state-based and community-based governance models exhibit important liabilities for governing unofficial roads. Whereas state-based governance has experienced difficulties in adapting to specific local contexts and interacting effectively with local peoples, community-based governance has a mixed record owing to social inequalities and conflicts among local interest groups. A state-community hybrid model may offer more effective governance of unofficial road building by combining the oversight capacity of the state with locally-grounded community management via participatory decision-making.

In 1995, a study found that the socioeconomic benefits from a legalized commercial harvest of sea turtle eggs in Ostional (Costa Rica) were substantial and widely recognized by Ostional residents. Legal and administrative structures ensured community participation in and control of resource use, and evidence indicated support for community-based conservation (CBC) was high. In 2004, the study was repeated to assess how perceptions of the egg harvest might have changed over time. There were continued high levels of support for conservation and positive perceptions of the project's impacts on the economy, environment and community. Some explanations for impact rankings have changed, with greater emphasis on the importance of conservation and awareness of how this is achieved, greater animosity towards one government agency and greater concern about the impacts of tourism on the egg harvesting project. Between surveys, a variety of social, political and economic changes have occurred. The CBC concept has been further refined and critiqued; by examining a CBC project over time, this paper considers the durability and flexibility of the incentive, legal and administrative structures associated with a successful example of CBC.

The steppes of the Mediterranean Basin, traditionally managed since ancient times, have been drastically degraded by recent human activities, and are a valuable model to study the impact of present and past anthropogenic disturbances. Climate and edaphic constraints and free sheep grazing have contributed for over 6000 years to the development of a steppe unique to France, but similar to many others in the Mediterranean Basin. This steppe is increasingly threatened by both industrialization and cultivation, and formerly-cultivated plots developed less species-rich vegetation than the steppe. Here, sampling with pitfall traps showed that formerly-cultivated plots hosted more diverse beetle assemblages owing to the presence of ruderal plants, which had greater nutritional value and hosted more phytophagous insects, beetles or other groups, enhancing prey diversity. The steppe had a less species-rich assemblage, but included many species typical of arid areas, some of which are threatened. Former disturbances led to the settlement of ubiquitous species, which increased the overall species richness, but decreased the biological value for conservation. Conservationists have to decide whether they would rather maintain beetle species diversity or biological value.

Environmental policy increasingly emphasizes involvement of local users and land owners in ecosystem management, but conservation planning is still largely a bureaucratic-scientific endeavour of identifying biological values for protection. Neither biological inventories nor stakeholder analyses, that tend to focus on conflicting interests, capture human resources in the landscape or the social structures and processes underlying biological conservation values. Social-ecological inventories are therefore proposed during the preparation phase of conservation projects as a means to identify people with ecosystem knowledge that practise ecosystem management. The method presented here focuses on local steward groups acting outside official management plans. In a social-ecological inventory of a river basin of southern Sweden, local steward groups, their ecosystem management activities, motives and links to other actors involved in ecosystem management were identified through interviews, participatory observations and a review of documents and other written material. Several hundred active local stewards were organized in 10 local steward groups that managed and monitored a range of ecosystem services at different spatial scales. Contributions of local stewards included on-site ecosystem management, long-term and detailed monitoring of species and ecosystem dynamics, local ecological knowledge, public support for ecosystem management and specialized networks. Two conservation projects are used to illustrate how local steward groups came together in multi-level networks and collaborated around specific conservation issues. The projects have been linked to ecosystem management at the landscape level through a flexible municipality organization, the Ecomuseum Kristianstads Vattenrike (EKV). EKV has acted as a ‘bridging organization’, coordinating and connecting many of the local steward groups to organizations and institutions at other levels. The process has been guided by social capital and shared visions for the whole landscape. The study shows that ecosystem management likely relies on multi-level collaboration and social-ecological inventories may help identify actors that are fundamental in such management systems. Social-ecological inventories should be employed in any attempt to develop and implement ecosystem management.

Indigenous people have widely been blamed for degrading South Asia's montane forest resources through the practice of shifting cultivation, yet some studies have revealed that indigenous people used forests in a sustainable way for centuries until external intervention. The history of external intervention in the forests of South Asia is more than two centuries old. The process of degradation of forest resources requires understanding of the political and social processes that condition access, control and management of the land and resources involved. The Chittagong Hill Tracts (CHT) of Bangladesh, a part of the Himalayan region, underwent essentially the same socio-political and historical processes as many other countries in the region and had very similar experiences in forest management. By examination of policies and associated effects on CHT forest over the past two centuries, this paper reveals that the process of forest degradation in the CHT started during the British colonial period with the nationalization of forests, establishment of reserve forests (RFs), management of forests by government agencies and weakening of traditional institutions. The process of degradation was accelerated by: privatization of forest land for the promotion of sedentary agriculture, horticulture and rubber plantation; the construction of a hydraulic dam on the Karnafuli River; the settlement of lowland people; and the constant conflict between indigenous people and the Forest Department. The degradation of CHT forests is not only the result of traditional agricultural practices, but also of many other factors including inappropriate policies and programmes.

Conservation in a dynamic setting requires understanding the factors leading to landscape change. This study integrated traditional remote sensing and geographic information systems analysis techniques with a narrative policy analysis to assess the 1975–2004 land cover changes and their determinants in Nam Dong district (central Vietnam). Total forest cover of Nam Dong remained stable, but there were major transitions within forest and non-forest categories. Recent policy initiatives, particularly forest land allocation, have resulted in short-term benefit maximization through land speculation and illegal logging, while increased awareness of the economic potential of forests and their products have motivated people to access forests more frequently, leading to a highly dynamic landscape and increased barriers to forest conservation. This study suggests that (1) state-sponsored logging needs to be reduced, (2) forest allocation should proceed more rapidly to give farmers better incentive to improve and protect allocated forests, and (3) small-scale industry should increase. Forest conservation policy must be amended. More research is needed to link household land-use choices with policies, and determine how those choices lead to changes in the landscape.