The degree and direction of morphological change in invasive species with a long history of introduction are insufficiently known for a larger scale than the archipelago or island group. Here, I analyse data for 105 island populations of Polynesian rats, Rattus exulans, covering the entirety of Oceania and Wallacea to test whether body size differs in insular populations and, if so, what biotic and abiotic features are correlated with it. All insular populations of this rat, except one, exhibit body sizes up to twice the size of their mainland conspecifics. Body size of insular populations is positively correlated with latitude, consistent with thermoregulatory predictions based on Bergmann's rule. Body size is negatively correlated with number of co-occurring mammalian species, confirming an ecological hypothesis of the island rule. The largest rats are found in the temperate zone of New Zealand, as well as on mammalian species-poor islands of Polynesia and the Solomon Islands. Carnivory in the form of predation on nesting seabird colonies seems to promote 1.4- to 1.9-fold body size increases.

This paper concerns itself with the contributions that the Humanities make to the understanding of islands and their bettered environmental conservation. Most distinctively, the Humanities comprise Literary Studies, Studies in Art and Culture (including Indigenous and Gender Studies) and Philosophy (with Aesthetics and the History of Ideas), but they also encompass Archaeology, History, Linguistics, Studies in Religion and, of late, Media and Communication Studies, even though members of this latter cluster frequently deploy methods from the social sciences. The goal here is to explore many of the implications such Human Studies and their sub-branches may have for island conservation, above all informed by the History of Ideas, in order to introduce the relevant key issues and inter-relationships and offer the most judicious illustrative materials. Variances in the reach and special attention of all these branches of knowledge are vast and intricate, while complex relativities apply both in the types of island situations and in expectations about what can or should be conserved. Since the mass of apposite discussions in the literature cannot possibly be summarized here, this article circumvents the difficulties by means of a special double-edged review. It ranges over the history of human consciousness of insular worlds, as reflected in mythic, legendary and historical materials, yet en route it uncovers how Humanities research can elucidate the human responses to islands through known time and shows how developing meaning-making has generally enhanced the appeal of sea-locked environments as worth conserving.

Because of their isolation, biotic communities of urban green spaces are expected to be similar to those of oceanic islands. This should be particularly true for insects, which represent an important component of urban faunas. The equilibrium theory of island biogeography (ETIB) allows for the formulation of some hypotheses regarding the influence of the geographical characteristics of green spaces on insect species richness and extinction risk. Based on island biogeography principles, we present eight predictions on how green space characteristics should influence insect species richness and loss. We analysed the current literature in order to determine which predictions were supported and which were not. We found that many studies gave outcomes that support ETIB predictions about the effects of area and isolation of green spaces; we found no strong support for predictions about shape and extent of native habitat in the literature that we reviewed. Most of the available studies dealt with patterns in species richness, whereas insect species loss has been rarely investigated. Future developments in the application of island biogeography principles to urban insect conservation should address temporal trends in species persistence and the analysis of species co-occurrence and nestedness.

The degradation, alteration and depletion of riparian habitats caused by river regulation are among critical conservation concerns. Aquatic and riparian habitats support not only river-dwelling biota such as macroinvertebrates and fish, but also waterbirds, the top predators in the aquatic food web. Despite the intimate relationships between fish and waterbirds, the two groups are often investigated separately. Using an integrative approach, we examined the effects of dams on fish and scaly-sided merganser (Mergus squamatus), an endangered, iconic riverine species, where the lack of knowledge about habitat preferences greatly hampers long-term conservation efforts. Our analysis quantified three causal links: (1) water depth had direct, comparable, negative effects on both fish and waterbirds, and the path coefficients for fish and birds are –0.31 and –0.46, respectively; (2) river landscape heterogeneity directly and positively affected fish and waterbirds, and the path coefficients for fish and birds are 0.63 and 0.19, respectively; and (3) depth and river landscape also exerted indirect effects on waterbirds through their impacts on fish abundance, and the path coefficients for fish and birds are –0.15 and 0.28, respectively. Our findings could contribute to the rational spatial planning and sustainable operation of dams in that maintaining instream habitat availability and heterogeneity would benefit the whole riverine ecosystem.

This overview explores sustainable development in island contexts. More subtle and complex concepts of sustainable development have become manifest in the Sustainable Development Goals, with tensions between social, economic and environmental objectives at different scales as livelihoods acquire greater flexibility and islands face multiple challenges to development. Islands are part of rapidly changing and wider worlds, while sustainability is complicated by global change, as debates over strategies and time periods are accentuated in constrained island contexts. Development and sustainability have repeatedly acquired new meanings, hence requiring new analytical techniques, planning objectives and effective governance and management. Progress towards sustainable development in islands and island states is hampered by multi-scalar challenges, including limited biodiversity, migration, external interventions and directives, scarce human resources, weak management, inadequate data (and problems of interpretation), social divisions and tensions and simultaneous quests for modernity and conservation. The tourism sector emphasizes how sustainable development is particularly difficult to achieve in small islands where access to adequate livelihoods is important and limited change is possible.

Recent extinction rates suggest that humans are now causing the sixth mass extinction, and the Mediterranean islands are at the forefront of many of the environmental issues involved. This study provides an alternative approach for investigating documented local plant extinctions that occurred in Sardinia (western Mediterranean) during the last half century. A total of 190 local extinctions of 62 plant species were used to investigate the independent effects of eight ecological and anthropogenic variables and to model the areas of potential extinctions where plant conservation efforts could be focused. If all analysed plant species were considered together, ecological factors explained local extinctions more than anthropogenic factors. The independent effects of each factor considerably varied among species of different lifeforms and altitude ranges. Accordingly, distribution models of local extinctions outscored areas that are potentially rich in plant species with conservation interest, but which are particularly affected by humans. This paper suggests a reproducible, operational framework for analysing which extinction factors may play important roles in similar contexts and where they might be relevant.

Identifying the drivers of bushmeat consumption and hunting is important for informing conservation strategies and recognizing challenges to human food security. However, studies often neglect the importance of landscape context, which can influence bushmeat supply and demand. Here, by quantifying bushmeat consumption and hunting in 262 households in a post-frontier region in Amazonia, we tested the hypotheses that bushmeat consumption and hunting are positively associated with two landscape characteristics: (1) forest cover, which has been shown to define game availability; and (2) remoteness, which is related to limited access to marketed meat. Bushmeat consumption was widespread but more likely in remote forested areas. Hunting was more likely in more forested areas, especially nearer to urban centres. Our findings suggest that bushmeat remains an important food source even in heavily altered forest regions and that landscape context is an important determinant of bushmeat consumption and hunting. Although people living in remote, forested areas are likely to be the most dependent on bushmeat, those living in more populous, peri-urban areas are likely the actors contributing most to total hunting effort, due to a higher probability of hunting combined with higher human population densities. This finding undermines the assumption that rural–urban migration in the tropics will deliver a much-needed reprieve for many overhunted species.

Using islands as a model system, this paper seeks to understand how ecosystem service valuation (ESV) has and can move from a monetized, single-service paradigm to an integrated valuation paradigm, a participatory approach that represents a more diverse set of the values of nature, and beyond, to a more fully realized conception of the island social–ecological systems. A systematic literature review of 314 island ESV studies reveals developments in the design, implementation and adoption of ESV studies over time. We complement the review with three cases where this evolution is happening, thereby offering insights into successful means of translating ESV into information useful for island system-scale management, policy design and planning. Over the past 30 years, both the number of studies and the number of services addressed per study have steadily grown, and valuation methods have become more inclusive of multiple values. The cases reveal lessons for ESV practice. Insights are that ESV should increasingly: (i) recognize strong interconnections between ecosystems and between human and environmental systems; (ii) move towards more integrated valuation methods that better capture the diverse values of nature; and (iii) be based on an iterative process where knowledge and decision-support tools are co-created with decision-makers and stakeholders.

Oceania can be characterized by a richness of culture, biodiversity and natural resources and a particular future that the changing climate will bring to islands, livelihoods and ecosystems. We reviewed literature detailing the limitations of siloed approaches to public health and conservation action for regional sustainability, highlighting opportunities for regional integration as place-based, through activities that are locally relevant, innovative engagement across a broader variety of sectors and working with indigenous peoples’ knowledges. We present three case studies that extend and redefine the boundaries of the fields of public health and conservation, enabling collaborators to better respond to complex issues impacting biodiversity and human health. These case studies make explicit the links between nutrition, catchment management, water resources, fisheries, marine protected areas and communicable and non-communicable diseases. Public health and conservation are more meaningfully connected in place-based, reciprocal and compassionate activities, using common language to draw on the well-developed instruments of both sectors. These will include health impact assessments and combine health and ecological economics, which together will contribute to responding to an emergent set of challenges, namely human population increase, urbanization, overfishing and more severe aspects of climate change.

This paper analyses the interdependence between environment and society in terms of socio-ecological webs, in which human and biophysical systems are linked. A quantitative model, based on canonical correlation analysis applied in Fuerteventura Island (Canary Archipelago), detected indicators of human–landscape relationships and predicted potential shifts based on simulated environmental changes. In the last few decades, the landscape of Fuerteventura Island has changed: natural components and cultural agrarian uses have decreased, while the population has increased due to immigration, mainly from mainland Spain and other European countries. The island shows a transition from a coupled local socio-ecosystem to one based on the interaction between environment and coastal tourism that decouples native inhabitants from the landscape and traditional land-use practices. As vulnerability and adaptation to climate change represent critical sets of potential interactions in Canary Islands, a model and a map of the socio-ecological system under four Intergovernmental Panel on Climate Change scenarios show rural decoupling through ‘deagrarianization’ and ‘deruralization’, as well as stronger links to the tourism system.

Small islands can guide visualization of the diverse information requirements of future context-relevant coastal governance. On small marine islands (<20 000 km2), negative effects of coastal challenges (e.g., related to population growth, unsustainable resource use or climate change) can develop rapidly, with high intensity and extreme impacts. The smallest and most remote islands within small-island states and small islands in larger states can be threatened by intrinsic governance factors, typically resulting in access to fewer resources than larger islands or administrative centres. For these reasons, efforts to support coastal change governance are critical and need to be targeted. We propose a conceptual framework that distinguishes key governance-related components of small-island social–ecological systems (SESs). To prioritize areas of vulnerability and opportunity, physical, ecological, social, economic and governance attributes are visualized to help show the ability of different types of small-island SESs to adapt, or be transformed, in the face of global and local change. Application of the framework to an Indonesian archipelago illustrates examples of local rule enforcement supporting local self-organized marine governance. Visualization of complex and interconnected social, environmental and economic changes in small-island SESs provides a better understanding of the vulnerabilities and opportunities related to context-specific governance.

Providing benefits to local people from forest conservation programmes is an important issue for policy makers. Livelihood projects are a common way to provide benefits, but there is little information about their costs. We analysed 463 livelihood projects in the Ankeniheny-Zahamena Corridor Reducing Emissions from Deforestation and Degradation (REDD+) pilot project in Madagascar to understand how different approaches to delivering livelihood projects affect costs. We compared costs across four approaches: conservation agreements, small grants, direct implementation and application of social safeguards. The approach impacted overall costs and the proportion of funds reaching communities. Projects implemented as safeguards were most expensive and had the lowest proportion of expenditures reaching the community. Projects provided as part of conservation agreements directed the highest proportion of expenditures to communities. Our results highlight that how livelihood projects are delivered has implications for project costs and community benefits and should be an important consideration in the design and implementation of REDD+ and forest conservation policies.

In this paper, we puzzle the way that sovereignty has been a sketchily present dynamic in conservation discourses. In the case of the world's many island communities whose colonial histories extend into the present in virtually every domain, silences around sovereignty in conservation contexts are particularly notable for the way they suggest the enduring domination of local communities by distant metropoles. Here, we provide a review of several critical issues in Pacific Islands contexts – biosecurity, food security, intellectual and material property rights and protected areas – that highlight the importance of conceptualizing sovereignty beyond the state to better enhance conservation outcomes. The novel approach we take in regard to these problems is to encourage conservation practitioners to more deeply engage with the ‘ecological futures’ that indigenous and local island communities are weaving in a period of active (re)articulations of sovereignty in conception, legal constitution and everyday engagements with island environments.

Small-scale mariculture of high-value species for trade in remote islands can offer valuable alternative livelihoods to local communities. The endangered giant clam species Tridacna maxima is naturally abundant in some atolls in French Polynesia (FP) and has been the focus of commercial mariculture activities since 2012. Shortly after spat collectors became operational in two atoll lagoons, FP rose to become one of the main exporters of giant clams for the aquarium trade. However, this activity has been threatened recently by a mass clam-bleaching event triggered by the 2015–2016 El Niño. This study reviews the roles that international (Convention on International Trade in Endangered Species of Wild Fauna and Flora) and national regulatory frameworks play in the development of this activity in a small island context, and how they can indirectly promote better science and monitoring in order to inform adaptive management strategies. The links between the nine main groups of stakeholders show the necessary adaptation measures required to mitigate climate-driven mortalities. While this case study remains specific to giant clam farming in FP, general lessons are provided that could help in mitigating economic impacts from climate-related events on other islands.

This article appreciatively reviews environmental education practice on islands through the lens of four key strands of environmental education discourse: biodiversity, conservation and science-framed education; place-based, indigenized and bioregional education; climate change and disaster risk reduction education; and education for sustainable development. Arising from these strands and their interface, six questions are asked of the examples of island practice reviewed. A final section asks what is distinctive about environmental education on islands and comes up with five principal findings. First, it is observed that environmental education initiatives on islands are markedly eclectic in their rich blending of practice from within the different strands. Second, it is noted that environmental education practice on different islands, especially in the Pacific, is marked by a return to indigenous, community-based learning. Third, the emergence of a distinctive pedagogy is remarked upon, especially the greater weighting given to relational, socio-affective and action-orientated learning. Fourth, the paucity of inter-island cosmopolitan dialogue is noted and questions are asked about how to ensure island learners steeped in learning about place can be brought to connect with the global environmental problematic. Fifth, the frequency of cross-curricular, interdisciplinary, even trans-disciplinary framing of environmental education initiatives is identified as bringing distinctiveness to island practice.

In spite of significant investment, community-based conservation often suffers from a lack of appropriate design. In this study, drawing on 86 interviews around six national parks in tropical Africa, we analyse the perceptions of different stakeholders (e.g. governmental officials, non-governmental organization staff and researchers) regarding community participation. Our results mainly reveal the absence of a clear and shared definition of community participation. While 67% of the participants defined community participation as a community's support of nature protection (low empowerment) and/or as its participation in conservation implementation (medium empowerment), 28% mentioned that the community should also participate in decision-making (high empowerment). Our study shows that participants with no university degree, belonging to governmental organizations and/or employed as workers tend to propose a lower level of empowerment, while those educated to a postgraduate level, belonging to research institutes and/or employed as researchers propose higher degrees of empowerment. Our study mainly suggests that the different degrees of empowerment proposed by the stakeholders depend on their relation to the space of conservation and their daily connection to practical management as drivers of the inclusion or exclusion of local communities in conservation decision-making. To properly design and implement community-based conservation, conservation actors above all must share a common definition of the concept.

The expansion of human settlements and primary-sector activities (agriculture and forestry) has resulted in the fragmentation of forests, but the impacts of this are still poorly understood. We examined the effect of patch size on the presence of plant functional groups along an edge–interior gradient. Plant species were classified based on a two-way indicator species analysis in order to determine their establishment thresholds and vulnerability along the gradient, while detrended correspondence analyses and canonical correspondence analyses were performed to identify environmental gradients related to vegetation distribution. Two groups of plant species were recognized in all patch sizes: one commonly found towards the edge and the other in the interior zone. The incidence of these groups was correlated with environmental factors associated with the edge–interior gradient, mainly with humidity, soil moisture and light (canopy opening and global site factor) in the edge zone and with litter cover, depth of litter, slope and soil and air temperature in the interior zone. Identifying the species’ threshold responses to fragmentation is key, as they provide tools to prevent the potential local extinction of species.

In many developing countries, high rates of deforestation and biodiversity loss make conservation efforts urgent. Improving existing land-use plans can be an option for enhancing biodiversity conservation. We showcase an approach to enhancing an existing forest land-use plan using widely available data and spatial tools, focusing on Argentina's Southern Yungas ecoregion. We mapped the distribution of wilderness areas and species and habitats of conservation concern, assessed their representation in the land-use plan and quantified potential changes in habitat availability and forest connectivity. Wilderness comprised 48% of the study area, and the highest concentrations of elements of conservation concern were in the north. In the current land-use plan, wilderness areas often occur in regions where logging and grazing are allowed, and a large proportion of the forest with the highest conservation value (43%) is under some level of human influence. Furthermore, we found that deforestation being legally allowed in the land-use plan could reduce forest connectivity and habitat availability substantially. We recommend updating the current land-use plan by considering human influence and elements of conservation concern. More broadly, we demonstrate that widely available spatial datasets and straightforward approaches can improve the usefulness of existing land-use plans so that they more fully incorporate conservation goals.

The East Asian–Australasian flyway contains some of the most threatened habitats in the world, with at least 155 waterbird species reliant on the tidal habitats it comprises. The black-faced spoonbill (Platalea minor) is an iconic endangered species distributed across the coast of East Asia. Its population suffered a severe decline into the 1990s, but extensive monitoring and conservation interventions have aided a substantial recovery of the species. We used a population viability analysis based on data collected over the past two decades in conjunction with species distribution models to project spatially explicit models of population change for the next 35 years. Over nearly all scenarios of habitat loss and climate change, the global spoonbill population was projected to increase in the short-term due to low population numbers likely well below current population carrying capacities. However, climate change and habitat loss together threaten the recovery of the spoonbill population such that, by 2050, population declines are apparent as a consequence of these cumulative impacts. These threats are also cryptic and represent a challenge to the conservation of species recovering from anthropogenic impacts; observed population increases can hide large reductions in habitat suitability that threaten the long-term viability of species.

Islands offer unique model systems for studying fisheries development in relation to the growing global seafood trade. This study examines how export-driven fisheries in India's oceanic islands (Andaman and Nicobar Islands and Lakshadweep Islands) differ significantly as a result of their varied history, culture, available infrastructure and market access. Despite being geographically closer to export centres on the Indian mainland, processing and transport infrastructure in the Lakshadweep Islands are limited. This only allows for the trade of non-perishable commodities like dried tuna that are caught using traditional pole-and-line fishing techniques, restricting reef exploitation to local preference-based consumption and opportunistic export. The Andaman Islands, on the other hand, with multiple daily flight connections and large private and government processing facilities, are better connected to export markets. The relatively recent and multicultural fisheries of these islands supply marine commodity chains for reef fishery goods such as dried shark fins, frozen snapper fillets and chilled groupers. The Nicobar Islands are furthest away from mainland export centres and are mostly populated by indigenous communities – fishing here is mostly for subsistence and local sale. Revised estimates of travel times to export market centres are counterintuitive in terms of geographical distances and are significantly different from travel times to local markets.