Showing papers in "Ecology and Society in 2004"
TL;DR: The concept of resilience has evolved considerably since Holling's (1973) seminal paper as discussed by the authors and different interpretations of what is meant by resilience, however, cause confusion, and it can be counterproductive to seek definitions that are too narrow.
Abstract: The concept of resilience has evolved considerably since Holling’s (1973) seminal paper. Different interpretations of what is meant by resilience, however, cause confusion. Resilience of a system needs to be considered in terms of the attributes that govern the system’s dynamics. Three related attributes of social– ecological systems (SESs) determine their future trajectories: resilience, adaptability, and transformability. Resilience (the capacity of a system to absorb disturbance and reorganize while undergoing change so as to still retain essentially the same function, structure, identity, and feedbacks) has four components—latitude, resistance, precariousness, and panarchy—most readily portrayed using the metaphor of a stability landscape. Adaptability is the capacity of actors in the system to influence resilience (in a SES, essentially to manage it). There are four general ways in which this can be done, corresponding to the four aspects of resilience. Transformability is the capacity to create a fundamentally new system when ecological, economic, or social structures make the existing system untenable. The implications of this interpretation of SES dynamics for sustainability science include changing the focus from seeking optimal states and the determinants of maximum sustainable yield (the MSY paradigm), to resilience analysis, adaptive resource management, and adaptive governance. INTRODUCTION An inherent difficulty in the application of these concepts is that, by their nature, they are rather imprecise. They fall into the same sort of category as “justice” or “wellbeing,” and it can be counterproductive to seek definitions that are too narrow. Because different groups adopt different interpretations to fit their understanding and purpose, however, there is confusion in their use. The confusion then extends to how a resilience approach (Holling 1973, Gunderson and Holling 2002) can contribute to the goals of sustainable development. In what follows, we provide an interpretation and an explanation of how these concepts are reflected in the adaptive cycles of complex, multi-scalar SESs. We need a better scientific basis for sustainable development than is generally applied (e.g., a new “sustainability science”). The “Consortium for Sustainable Development” (of the International Council for Science, the Initiative on Science and Technology for Sustainability, and the Third World Academy of Science), the US National Research Council (1999, 2002), and the Millennium Ecosystem Assessment (2003), have all focused increasing attention on such notions as robustness, vulnerability, and risk. There is good reason for this, as it is these characteristics of social–ecological systems (SESs) that will determine their ability to adapt to and benefit from change. In particular, the stability dynamics of all linked systems of humans and nature emerge from three complementary attributes: resilience, adaptability, and transformability. The purpose of this paper is to examine these three attributes; what they mean, how they interact, and their implications for our future well-being. There is little fundamentally new theory in this paper. What is new is that it uses established theory of nonlinear stability (Levin 1999, Scheffer et al. 2001, Gunderson and Holling 2002, Berkes et al. 2003) to clarify, explain, and diagnose known examples of regional development, regional poverty, and regional CSIRO Sustainable Ecosystems; University of Wisconsin-Madison; Arizona State University Ecology and Society 9(2): 5. http://www.ecologyandsociety.org/vol9/iss2/art5 sustainability. These include, among others, the Everglades and the Wisconsin Northern Highlands Lake District in the USA, rangelands and an agricultural catchment in southeastern Australia, the semi-arid savanna in southeastern Zimbabwe, the Kristianstad “Water Kingdom” in southern Sweden, and the Mae Ping valley in northern Thailand. These regions provide examples of both successes and failures of development. Some from rich countries have generated several pulses of solutions over a span of a hundred years and have generated huge costs of recovery (the Everglades). Some from poor countries have emerged in a transformed way but then, in some cases, have been dragged back by higher-level autocratic regimes (Zimbabwe). Some began as localscale solutions and then developed as transformations across scales from local to regional (Kristianstad and northern Wisconsin). In all of them, the outcomes were determined by the interplay of their resilience, adaptability, and transformability. There is a major distinction between resilience and adaptability, on the one hand, and transformability on the other. Resilience and adaptability have to do with the dynamics of a particular system, or a closely related set of systems. Transformability refers to fundamentally altering the nature of a system. As with many terms under the resilience rubric, the dividing line between “closely related” and “fundamentally altered” can be fuzzy, and subject to interpretation. So we begin by first offering the most general, qualitative set of definitions, without reference to conceptual frameworks, that can be used to describe these terms. We then use some examples and the literature on “basins of attraction” and “stability landscapes” to further refine our definitions. Before giving the definitions, however, we need to briefly introduce the concept of adaptive cycles. Adaptive Cycles and Cross-scale Effects The dynamics of SESs can be usefully described and analyzed in terms of a cycle, known as an adaptive cycle, that passes through four phases. Two of them— a growth and exploitation phase (r) merging into a conservation phase (K)—comprise a slow, cumulative forward loop of the cycle, during which the dynamics of the system are reasonably predictable. As the K phase continues, resources become increasingly locked up and the system becomes progressively less flexible and responsive to external shocks. It is eventually, inevitably, followed by a chaotic collapse and release phase (Ω) that rapidly gives way to a phase of reorganization (α), which may be rapid or slow, and during which, innovation and new opportunities are possible. The Ω and α phases together comprise an unpredictable backloop. The α phase leads into a subsequent r phase, which may resemble the previous r phase or be significantly different. This metaphor of the adaptive cycle is based on observed system changes, and does not imply fixed, regular cycling. Systems can move back from K toward r, or from r directly into Ω, or back from α to Ω. Finally (and importantly), the cycles occur at a number of scales and SESs exist as “panarchies”— adaptive cycles interacting across multiple scales. These cross-scale effects are of great significance in the dynamics of SESs.
5,745 citations
TL;DR: This paper looks at the institutional configurations that affect the interactions among resources, resource users, public infrastructure providers, and public infrastructures and proposes a framework that helps identify potential vulnerabilities of SESs to disturbances.
Abstract: What makes social-ecological systems (SESs) robust? In this paper, we look at the institutional configurations that affect the interactions among resources, resource users, public infrastructure providers, and public infrastructures. We propose a framework that helps identify potential vulnerabilities of SESs to disturbances. All the links between components of this framework can fail and thereby reduce the robustness of the system. We posit that the link between resource users and public infrastructure providers is a key variable affecting the robustness of SESs that has frequently been ignored in the past. We illustrate the problems caused by a disruption in this link. We then briefly describe the design principles originally developed for robust common-pool resource institutions, because they appear to be a good starting point for the development of design principles for more general SESs and do include the link between resource users and public infrastructure providers.
1,440 citations
TL;DR: In this paper, the authors argue that societies and communities dependent on natural resources need to enhance their capacity to adapt to the impacts of future climate change, particularly when such impacts could lie outside their experienced coping range.
Abstract: Emerging insights from adaptive and community-based resource management suggest that building resilience into both human and ecological systems is an effective way to cope with environmental change characterized by future surprises or unknowable risks. We argue that these emerging insights have implications for policies and strategies for responding to climate change. We review perspectives on collective action for natural resource management to inform understanding of climate response capacity. We demonstrate the importance of social learning, specifically in relation to the acceptance of strategies that build social and ecological resilience. Societies and communities dependent on natural resources need to enhance their capacity to adapt to the impacts of future climate change, particularly when such impacts could lie outside their experienced coping range. This argument is illustrated by an example of present-day collective action for community-based coastal management in Trinidad and Tobago. The case demonstrates that community-based management enhances adaptive capacity in two ways: by building networks that are important for coping with extreme events and by retaining the resilience of the underpinning resources and ecological systems
1,128 citations
TL;DR: In this article, a combination of traditional ecological knowledge and science to monitor populations can greatly assist co-management for sustainable customary wildlife harvests by indigenous peoples, which can not only build partnership and community consensus, but also allow indigenous wildlife users to critically evaluate scientific predictions on their own terms and test sustainability using their own forms of adaptive management.
Abstract: Using a combination of traditional ecological knowledge and science to monitor populations can greatly assist co-management for sustainable customary wildlife harvests by indigenous peoples. Case studies from Canada and New Zealand emphasize that, although traditional monitoring methods may often be imprecise and qualitative, they are nevertheless valuable because they are based on observations over long time periods, incorporate large sample sizes, are inexpensive, invite the participation of harvesters as researchers, and sometimes incorporate subtle multivariate cross checks for environmental change. A few simple rules suggested by traditional knowledge may produce good management outcomes consistent with fuzzy logic thinking. Science can sometimes offer better tests of potential causes of population change by research on larger spatial scales, precise quantification, and evaluation of population change where no harvest occurs. However, science is expensive and may not always be trusted or welcomed by customary users of wildlife. Short scientific studies in which traditional monitoring methods are calibrated against population abundance could make it possible to mesh traditional ecological knowledge with scientific inferences of prey population dynamics. This paper analyzes the traditional monitoring techniques of catch per unit effort and body condition. Combining scientific and traditional monitoring methods can not only build partnership and community consensus, but also, and more importantly, allow indigenous wildlife users to critically evaluate scientific predictions on their own terms and test sustainability using their own forms of adaptive management.
937 citations
TL;DR: Olsson et al. as mentioned in this paper analyzed the emergence of an adaptive co-management system for wetland landscape governance in southern Sweden, a process where unconnected management by several actors in the landscape was mobilized, renewed, and reconfigured into ecosystem management within about a decade.
Abstract: We analyze the emergence of an adaptive co-management system for wetland landscape governance in southern Sweden, a process where unconnected management by several actors in the landscape was mobilized, renewed, and reconfigured into ecosystem management within about a decade. Our analysis highlights the social mechanisms behind the transformation toward ecosystem management. The self-organizing process was triggered by perceived threats among members of various local stewardship associations and local government to the area’s cultural and ecological values. These threats challenged the development of ecosystem services in the area. We show how one individual, a key leader, played an instrumental role in directing change and transforming governance. The transformation involved three phases: 1) preparing the system for change, 2) seizing a window of opportunity, and 3) building social-ecological resilience of the new desired state. This local policy entrepreneur initiated trust-building dialogue, mobilized social networks with actors across scales, and started processes for coordinating people, information flows and ongoing activities, and for compiling and generating knowledge, understanding, and management practices of ecosystem dynamics. Understanding, collaborative learning, and creating public awareness were part of the process. A comprehensive framework was developed with a shared vision and goals that presented conservation as development, turned problems into possibilities, and contributed to a shift in perception among key actors regarding the values of the wetland landscape. A window of opportunity at the political level opened, which made it possible to transform the governance system toward a trajectory of ecosystem management. The transformation involved establishing a new municipal organization, the Ecomuseum Kristianstads Vattenrike (EKV). This flexible organization serves as a bridge between local actors and governmental bodies and is essential to the adaptive governance of the wetland landscape. It is also critical in navigating the larger sociopolitical and economic environment for resilience of the new social-ecological system. We conclude that social transformation is essential to move from a less desired trajectory to one where the capacity to manage ecosystems sustainably for human well-being is strengthened. Adaptability among actors is needed to reinforce and sustain the desired social-ecological state and make it resilient to future change and unpredictable events. INTRODUCTION Social-ecological systems are complex systems, the inherent features of which are change and uncertainty (Gunderson and Holling 2002). To strengthen our capacity to deal with uncertainty and change and to sustain ecosystem services, we must be able to monitor, interpret, and respond to ecosystem feedback (Gadgil et al. 1993, Berkes et al. 2003). Knowledge generation of ecosystem dynamics and the capacity to respond to ecosystem feedback among local resource users and steward associations tend to be integrated with management practices and evolve with the Human well-being and progress toward sustainable development are vitally dependent on improved management of the Earth’s ecosystems. The focus of the international Millennium Ecosystem Assessment is to strengthen our capacity to manage ecosystems sustainably to ensure continued provision of essential services. This process requires an understanding of not only the ecological system but the integrated socialecological system (Berkes and Folke 1998). Center for Transdisciplinary Environmental Research Ecology and Society 9(4): 2. http://www.ecologyandsociety.org/vol9/iss4/art2 institutional and organizational aspects of management in what we refer to as adaptive co-management systems (Olsson et al. 2004). Adaptive comanagement is the combination and operationalization of adaptive management (Holling 1978) and adaptive governance (Dietz et al. 2003). Adaptive co-management focuses on creating functional feedback loops between social and ecological systems. It relies on collaboration among a diverse set of actors operating at different levels, often in networks, from local users to municipalities to regional and national or supranational organizations. Adaptive co-management systems have been defined as flexible community-based systems of resource management tailored to specific places and situations, supported by, and working with, various organizations at different levels (Folke et al. 2003). Sharing management power and responsibility may involve multiple institutional links among user groups or communities, government agencies, and nongovernmental organizations. Hence, adaptive comanagement systems build on open institutions and learning (Shannon and Antypas 1997), drawing on a variety of sources of information and knowledge and avoiding set prescriptions of management superimposed on a particular place, situation, or context. Adaptive comanagement includes experimentation that provides opportunities to track desired and sustainable trajectories (Carpenter and Gunderson 2001). We have recently proposed that adaptive co-management of ecosystems has the potential to build resilience in social-ecological systems (Olsson et al. 2004). Socialecological resilience refers to the capacity of a socialecological system to absorb disturbance and reorganize while undergoing change so as to still retain essentially the same function, structure, identity, and feedbacks (Walker et al., in preparation). The ability to reorganize and renew a desired social-ecological system state following disturbance and change will strongly depend on the influences from states and dynamics at scales above and below. Such cross-scale aspects of resilience are captured in the notion of a panarchy, a set of dynamic systems nested across scales (Gunderson and Holling 2002). Hence, resilience reflects the degree to which a social-ecological system is capable of self-organization (vs. lack of organization, or organization forced by external factors) and the degree to which the system can build and increase the capacity for learning and adaptation (Carpenter et al. 2001). The capacity to adapt to and shape change is an important component of social-ecological system resilience (Berkes et al. 2003). In a social-ecological system with high adaptability, the actors have the capacity to sustain the system in desired states in response to changing conditions and disturbance events. What sustains the adaptive capacity of social-ecological systems in a world that is constantly changing? Following the work of Berkes and Folke (1998), Tengö and Hammer (2003) identify a bundle of management practices in a small-holder Tanzanian agropastoral society as part of adaptive capacity. Colding et al. (2003) summarize practices for coping with environmental variability and disturbance events that seem to confer resilience in social-ecological systems. Trosper (2003) suggests that the potlatch system among Indians on the Northwest Coast of the USA must have been characterized by adaptive capacity as it persisted for two millennia before these tribes had contact with people from the Old World. The characteristics of the system, namely property rights, environmental ethics, rules of earning and holding titles, public accountability, and the reciprocal exchange system, provided all three elements of resilient social-ecological systems as defined above. Folke et al. (2003) identify and expand on four critical factors in complex social-ecological systems that interact across temporal and spatial scales and that seem to be required for dealing with ecosystem dynamics during periods of change and reorganization: learning to live with change and uncertainty, nurturing diversity for reorganization and renewal, combining different types of knowledge for learning, and creating opportunities for self-organization toward social-ecological sustainability. It is the last factor, in particular, that is the focus of this article and it relates to transformability, a concept under development within the Resilience Alliance (Walker et al., in preparation). Transformability is the capacity of a social-ecological system to move to a new configuration defined by new state variables or the old state variables supplemented by new ones. New variables are introduced or allowed to emerge to create untried beginnings from which to evolve a new way of operating when existing ecological, economic, and social structures become untenable (Walker et al., in preparation). Here, we study the emergence of an adaptive comanagement system for wetland landscape management in southern Sweden, a process by which the prevailing management system was moved into a new configuration of ecosystem management within about a decade. Coordinated and collaborative Ecology and Society 9(4): 2. http://www.ecologyandsociety.org/vol9/iss4/art2 ecosystem management at the landscape and catchment level did not exist earlier. Hence, this article focuses on social change processes for establishing ecosystem management (Danter et al. 2000) and, following the work of Berkes and Folke (1998), Berkes et al. (2003), and Gunderson and Holling (2002), on elucidating social mechanisms behind such management or, more specifically, social mechanisms of adaptability and transformability. The starting point for our analysis was the observation of a policy change by the Municipality of Kristianstad in 1989 that adopted a new approach for managing the wetland ecosystems of the lower Helgeå River catchment, in southern Sweden (Fig. 1). The ecosystems in this area and the social structures and processes behind their management are defined as a social-ecological system (SES) (see Berkes and Folke 2002). The policy change was accompanied by an organizational change with the establishment of a new municipal organization, the Ecomuseum Kristianstads Vattenrike (EKV), which plays a key role in the
849 citations
TL;DR: The concept of cultural keystone species is explored, similarities to and differences from ecologicalKeystone species are described, examples from First Nations cultures of British Columbia are presented, and the application of this concept in ecological restoration and conservation initiatives is discussed.
Abstract: Ecologists have long recognized that some species, by virtue of the key roles they play in the overall structure and functioning of an ecosystem, are essential to its integrity; these are known as keystone species. Similarly, in human cultures everywhere, there are plants and animals that form the contextual underpinnings of a culture, as reflected in their fundamental roles in diet, as materials, or in medicine. In addition, these species often feature prominently in the language, ceremonies, and narratives of native peoples and can be considered cultural icons. Without these "cultural keystone species," the societies they support would be completely different. An obvious example is western red-cedar (Thuja plicata) for Northwest Coast cultures of North America. Often prominent elements of local ecosystems, cultural keystone species may be used and harvested in large quantities and intensively managed for quality and productivity. Given that biological conservation and ecological restoration embody human cultures as crucial components, one approach that may improve success in overall conservation or restoration efforts is to recognize and focus on cultural keystone species. In this paper, we explore the concept of cultural keystone species, describe similarities to and differences from ecological keystone species, present examples from First Nations cultures of British Columbia, and discuss the application of this concept in ecological restoration and conservation initiatives.
738 citations
TL;DR: A developing database established to address the need for research on a typology of thresholds is described, which comprises a set of summarized published examples and a searchable bibliographic database of publications on the topic.
Abstract: Increasing interest in regime shifts in ecological and linked social-ecological systems (SESs) has placed a strong focus on the thresholds of change. However, research into this topic has been hampered by a lack of empirical data. This paper describes a developing database established to address this need. The database is freely available and comprises a set of summarized published examples and a searchable bibliographic database of publications on the topic. Thresholds in the database are characterized in terms of a standardized set of 24 descriptors, including the variables along which they occur, the variables that change, and the factors that have driven the change. Readers are encouraged to contribute new examples. Examples range from conceptual models to empirical evidence. The former predominate in the literature and, although they make valuable contributions and will continue to be included, the intention is build up the number of examples based on data. Examples are presented in terms of whether the threshold occurs in the ecological system, the social system, or both, and the direction of interactions between systems. The paper concludes with some initial observations on thresholds based on the examples included so far, and poses some questions for future research. Research on a typology of thresholds is a priority topic in the emerging area of "sustainability science" and it requires a rich database of empirical data.
571 citations
TL;DR: In this paper, the authors apply a framework based on resilience theory to examine the region's resilience and capacity for change and renewal, using the Western Australian (WA) agricultural region as an example of a large-scale social-ecological system.
Abstract: Using the Western Australian (WA) agricultural region as an example of a large-scale social-ecological system (SES), this paper applies a framework based on resilience theory to examine the region's resilience and capacity for change and renewal. Despite numerous policies directed at controlling natural resource degradation in this SES, sustainable natural resource management (NRM) has not been achieved. Disparities between the scale and complexity of the problem, the design of management policies, and region's history have all contributed to policy resistance. Historically, when considered as an integrated system, changes may be described by two iterations of the adaptive cycle. These cycles are also synchronous with the third and fourth Kondratiev long-wave economic cycles. The WA agricultural region has experienced sequential periods of growth and accumulation followed by reorganization and renewal, and currently is in the backloop (reorganization to exploitation phases) of the adaptive cycle. A region's adaptive capacity is achieved by substituting direct reliance on regional factors with institutional intervention and sophisticated technology, often generated at the global scale. This substitution alters the thresholds of the commodity system and gives the perception of an adaptive system. In contrast, however, if resource depletion, environmental pollution, and population decline, also effects of the commodity system, are included within the model then the region may be considered to be in a Lock-in pathological trap. We propose that the dynamics of land-use change between 1900-2003 were driven by macroeconomics at the global scale, mediated by institutions at the national and state scale. Also, the SES, which is composed of relatively fast-moving variables, is largely decoupled from the slow-moving ecological variables.
400 citations
TL;DR: Simulations of alternative management strategies that attempt to rebuild shark and billfish populations in each ecosystem reveal that changes in longlining more effectively recover top predator populations than do changes in purse seining and restrictions on both shallow-set longline gear and shark finning may do more to recover top predators than do simple reductions in fishing effort.
Abstract: We use food-web models to develop visualizations to compare and evaluate the interactions of tuna fisheries with their supporting food webs in the eastern tropical Pacific (ETP) and the central north Pacific (CNP) Oceans. In the ETP and CNP models, individual fisheries use slightly different food webs that are defined by the assemblage of targeted tuna species. Distinct energy pathways are required to support different tuna species and, consequently, the specific fisheries that target different tuna assemblages. These simulations suggest that catches of tunas, sharks, and billfishes have lowered the biomass of the upper trophic levels in both systems, whereas increases in intermediate and lower trophic level animals have accompanied the decline of top predators. Trade- offs between fishing and predation mortality rates that occur when multiple fisheries interact with their respective food webs may lead to smaller changes in biomass than if only the effect of a single fishery is considered. Historical simulations and hypothetical management scenarios further demonstrate that the effects of longline and purse seine fisheries have been strongest in upper trophic levels, but that lower trophic levels may respond more strongly to purse-seine fisheries. The apex predator guild has responded most strongly to longlining. Simulations of alternative management strategies that attempt to rebuild shark and billfish populations in each ecosystem reveal that (1) changes in longlining more effectively recover top predator populations than do changes in purse seining and (2) restrictions on both shallow-set longline gear and shark finning may do more to recover top predators than do simple reductions in fishing effort.
306 citations
278 citations
TL;DR: In this article, the dynamics of and policies governing spatially coupled social-ecological mosaics are considered for the case of fisheries in a lake district, and the authors show that optimal policies will be highly heterogeneous in space and fluid in time.
Abstract: The dynamics of and policies governing spatially coupled social-ecological mosaics are considered for the case of fisheries in a lake district. A microeconomic model of households addresses agent decisions at three hierarchic levels: (1) selection of the lake district from among a larger set of alternative places to live or visit, (2) selection of a base location within the lake district, and (3) selection of a portfolio of ecosystem services to use. Ecosystem services are represented by dynamics of fish production subject to multiple stable domains and trophic cascades. Policy calculations show that optimal policies will be highly heterogeneous in space and fluid in time. The diversity of possible outcomes is illustrated by simulations for a hypothetical lake district based loosely on the Northern Highlands of the State of Wisconsin. Lake districts are frequently managed as if lakes were independent, similar, endogenously regulating systems. Our findings contradict that view. One-size-fits-all (OSFA) policies erode ecological and social resilience. If regulations are too stringent, social resilience declines because of the potential rewards of overharvesting. If regulations are too lax, ecological resilience is diminished by overharvesting in some lakes. In either case, local collapses of fish populations evoke spatial shifts of angling effort that can lead to serial collapses in neighboring fisheries and degraded fisheries in most or all of the lakes. Under OSFA management, the natural resources of the entire landscape become more vulnerable to transformation because of changes in, e.g., human population, the demand for resources, or fish harvesting technology. Multiplicity of management regimes can increase the ecological resilience, social resilience, and inclusive value of a spatially heterogeneous social-ecological system. Because of the complex interactions of mobile people and multistable ecosystems, management regimes must also be flexible over time. A rights-based scheme may facilitate policy regimes with appropriate spatial patterns and intertemporal fluidity. In lake fisheries, habitat protection adds an important dimension to policy design. Habitat is a slowly changing variable that creates ecological resilience and thereby provides managers with a broader range of options.
TL;DR: This article explored the effects of sprawl on native bird communities by comparing the occurrence of birds along gradients of urban land use in southwestern Ohio and northern California and by examining patterns at the individual, species, community, landscape, and continental levels.
Abstract: Urban sprawl affects the environment in myriad ways and at multiple levels of biological organization In this paper I explore the effects of sprawl on native bird communities by comparing the occurrence of birds along gradients of urban land use in southwestern Ohio and northern California and by examining patterns at the individual, species, community, landscape, and continental levels I do this by assessing the distribution and abundance of all bird species occupying sites of differing land-use intensity in Ohio and California Additionally, I conducted predation experiments using artificial nests, tracked the nest fate of American Robins and Northern Cardinals, and assessed land cover in these sites At the individual level, predation on artificial nests decreased with urbanization; however, this trend was not reflected in the nesting success of robins and cardinals, which did not increase with urbanization At the species level, sprawl affected local patterns of extinction and invasion; the density of different species peaked at different levels of urbanization At the community level, species richness and diversity peaked at moderate levels of urbanization, and the number of low-nesting species and of species with multiple broods increased with urbanization The community-level results may reflect both the species-level patterns of local extinction and invasion as well as broader landscape-level patterns At the landscape level, a linear combination of spatial heterogeneity and density of woody patches accurately predicted both species richness and Shannon Diversity At the continental level, local extinction of endemic species, followed by the invasion of ubiquitous weedy species, leads to faunal homogenization between ecoregions
TL;DR: It is recommended that endemic birds be tested for susceptibility to disease outside the Galapagos so that protection efforts can be better designed to deal with actual threats.
Abstract: Exotic diseases and parasites have caused extinctions on islands and continents, particularly when they spread through assemblages of immunologically naive species. Hawaii has lost a substantial part of its endemic bird fauna since the introduction of avian malaria at the beginning of the 20th century. In contrast, the Galapagos archipelago still possesses its entire endemic avifauna. Several of these Galapagos bird populations are in decline, however, and wildlife managers seek guidance to counteract a potential man-made ecological disaster. We recommend that endemic birds be tested for susceptibility to disease outside the Galapagos so that protection efforts can be better designed to deal with actual threats. At present, the best and perhaps only management option is to protect the isolation of these island communities because treating or vaccinating wild bird populations against diseases is almost impossible. If the isolation of the Galapagos Islands is successful, we will preserve the complete avifauna of an archipelago for the first time in the history of human colonization in the Pacific eco- region.
TL;DR: In this paper, the authors compared 61 case studies of the commercial production and trade of nontimber forest products from Asia, Africa, and Latin America and concluded that commercial trade drives a process of intensified production and household specialization among forest peoples.
Abstract: Engagement in the market changes the opportunities and strategies of forest-related peoples. Efforts to support rural development need to better understand the potential importance of markets and the way people respond to them. To this end, we compared 61 case studies of the commercial production and trade of nontimber forest products from Asia, Africa, and Latin America. The results show that product use is shaped by local markets and institutions, resource abundance, and the relative level of development. Larger regional patterns are also important. High-value products tend to be managed intensively by specialized producers and yield substantially higher incomes than those generated by the less specialized producers of less managed, low-value products. We conclude that commercial trade drives a process of intensified production and household specialization among forest peoples.
TL;DR: The authors assesses the possibility of using the ideas that are central to panarchy, developed on a regional scale, to help explain the changes that are being brought about on a global scale by the Internet and by climate, economic, and geopolitical changes.
Abstract: Panarchy focuses on ecological and social systems that change abruptly. Panarchy is the process by which they grow, adapt, transform, and, in the end, collapse. These stages occur at different scales. The back loop of such changes is a critical time and presents critical opportunities for experiment and learning. It is when uncertainties arise and when resilience is tested and established. We now see changes on a global scale that suggest that we are in such a back loop. This article assesses the possibility of using the ideas that are central to panarchy, developed on a regional scale, to help explain the changes that are being brought about on a global scale by the Internet and by climate, economic, and geopolitical changes.
TL;DR: In this paper, the authors introduce the field of mixture toxicity and the challenges in regulating pesticide mixtures, and present several challenges to adequately protect the environment from mixture toxicity; these challenges include understanding the interactions of toxicants within an organism, identifying the mixtures that most commonly occur and cause adverse effects, and developing a regulatory structure capable of minimizing environmental impacts.
Abstract: This paper introduces the field of mixture toxicity and the challenges in regulating pesticide mixtures. Even though pesticides are unique chemical stressors designed to have biological activity that can affect a number of nontarget species, they are intentionally placed into the environment in large quantities. Currently, methods and terminology for evaluating mixture toxicity are poorly established. The most common approach used is the assumption of additive concentration, with the concentrations adjusted for potency to a reference toxicant. Using this approach, the joint action of pesticides that have similar chemical structures and modes of toxic action can be predicted. However, this approach and other modeling techniques often provide little insight into the observed toxicity produced by mixtures of pesticides from different classes. Particularly difficult to model are mixtures that involve a secondary toxicant that changes the toxicokinetics of a primary toxicant. This may result in increased activation or a change in the persistence of the primary toxicant within the organism and may be responsible for a several-fold increase or decrease in toxicity. At present, the ecological effects caused by mixtures of pesticides are given little consideration in the regulatory process. However, mixtures are being considered in relation to human health in the pesticide registration process, setting a precedent that could be followed for ecological protection. Additionally, pesticide mixtures may be regulated through toxicity testing of surface water under the Clean Water Act. The limits of our basic knowledge of how mixtures interact are compromising both these avenues for regulating mixtures. We face many challenges to adequately protecting the environment from mixture toxicity; these challenges include understanding the interactions of toxicants within an organism, identifying the mixtures that most commonly occur and cause adverse effects, and developing a regulatory structure capable of minimizing environmental impacts.
TL;DR: In this paper, the effects of boat interactions on the behavioral budget of two populations of bottlenose dolphins (Tersiops truncatus) living in similar fjords but exposed to different levels of tourism activities were assessed.
Abstract: Increasingly, whales and dolphins are the focus of tourism activities in many coastal locations. Although these activities can affect individuals and populations of cetaceans, the biological significance and hence the cost of these impacts are as yet largely unknown. This study assessed the effects of boat interactions on the behavioral budget of two populations of bottlenose dolphins (Tersiops truncatus) living in similar fjords but exposed to different levels of tourism activities. This comparison makes it possible to assess the costs of short-term avoidance strategies and the threshold at which those strategies are no longer effective. The effects of boat
TL;DR: In this article, the authors discuss the heterogeneity and complexity of local ecological knowledge in relation to its practical and institutional context with respect to management of Himalayan medicinal plants and discuss how knowledge is put into action.
Abstract: The importance accorded to ethnoecological knowledge for suggesting new paths in scientific research, understanding ecological processes, and designing sustainable management of natural resources has grown in recent years. However, variation in knowledge and practices, both within and across cultures, has not been given much attention in resource management nor in developing scientific understanding of the ecological status of key resources. In this paper, we discuss the heterogeneity and complexity of local ecological knowledge in relation to its practical and institutional context with respect to management of Himalayan medicinal plants. We show factors affecting this variation, and discuss how knowledge is put into action. We assessed variation in knowledge relating to the diversity of medicinal plant species, their distribution, medicinal uses, biological traits, ecology, and management within and between two culturally different social groups living in villages located in the Shey-Phoksundo National Park and its buffer zone in northwestern Nepal. Heterogeneity in levels of knowledge and in practices both within and between these groups corresponds to differences in level of specialization in relation to medicinal plants, to socio-cultural and institutional contexts, and to extra-local factors that govern people’s activities. We argue that understanding the heterogeneity of knowledge and practices within a given area is crucial to design management practices that build on the intricate links between knowledge, practices, and institutional context. It is also important to develop ecological studies that will best inform management.
TL;DR: In this article, the authors used the power form of the Species-Area Relationship (SAR) to set conservation targets for land classes using biodiversity survey data, which can then be used to estimate the proportion of area required to represent a given proportion of species present in any land class.
Abstract: This paper demonstrates how the power form of the Species-Area Relationship (SAR) can be used to set conservation targets for land classes using biodiversity survey data. The log-transformation of the power model is a straight line; therefore, if one knows the average number of species recorded per survey site and can estimate the true species number present in the land class, using EstimateS software, it is possible to calculate the slope of the curve, or z-value. The z-value is the exponent in the power model and it can then be used to estimate the proportion of area required to represent a given proportion of species present in any land class. This application of the SAR is explored using phytosociological releve data from South Africa's Succulent Karoo biome. We also provide suggestions for extrapolating the estimated z-values to other land classes within a bioregion that lack sufficient survey data, using the relationship between z-values and remotely determined landscape variables such as habitat diversity (topographic diversity) and geographic location (latitude and longitude). The SAR predicts that for most Succulent Karoo vegetation types a conservation target of 10% of the land area would not be sufficient to conserve the majority of species. We also demonstrate that not all land classes are equal from a plant biodiversity perspective, so applying one target to all land classes in a region will lead to significant gaps and inefficiencies in any reserve network based on this universal target.
TL;DR: The capacity of human-dominated production ecosystems to sustain a flow of desired ecosystem services is strongly associated with local management practices and the governance system that they are embedded in, and that, contrary to what is often assumed, local management can and does add resilience for desired ecosystem service as discussed by the authors.
Abstract: The development of human societies rests on functioning ecosystems. This thesis builds on integrated theories of linked social-ecological systems and complex adaptive systems to increase the understanding of how to strengthen the capacity of ecosystems to generate services that sustain human well-being. In this work, I analyze such capacity in human-dominated production ecosystems in Tanzania and Madagascar, and how this capacity is related to local management practices. Resilience of social-ecological systems refers to the capacity to buffer change, to re-organize following disruption, and for adaptation and learning. In Papers I and II, qualitative interview methods are used for mapping and analyses of management practices in the agroecosystem of the Mbulu highlands, Northern Tanzania. Practices such as soil and water conservation, maintenance of habitats for pollinators and predators of pests, intercropping, and landscape diversification, act to buffer food production in a variable environment and sustain underlying ecological processes. The practices are embedded in a decentralized but nested system of institutions, such as communal land rights and social networks, that can buffer for localized disturbances such as temporary droughts. Paper II compares these findings with practices in a farming system in Sweden, and suggests that similar mechanisms for dealing with uncertainty and change can exist in spite of different biophysical conditions. In Papers III and IV, interviews are combined with GIS tools and vegetation sampling to study characteristics and dynamics of the dry forests of Androy, southern Madagascar. Paper III reports on a previously underestimated capacity of the dry forest of southern Madagascar to regenerate, showing areas of regeneration roughly equal areas of degenerated forest (18 700 ha). The pattern of forest regeneration, degradation, and stable cover during the period 1986-2000 was related to the enforcement of customary property rights (Paper III). Paper IV reports on a network of locally protected forest patches in Androy that is embedded in a landscape managed for agricultural or livestock production and contributes to the generation of ecosystem services and ecosystem resilience at a landscape scale. Forest protection is secured by local taboos that provide a well-functioning and legitimate sanctioning system related to religious beliefs. In Paper V, two spatial modeling tools are used to assess the generation of two services, crop pollination and seed dispersal, by the protected forest patches in southern Androy. The functioning of these services is dependent on the spatial configuration of protected patches in the fragmented landscape and can be highly vulnerable to even small changes in landscape forest cover. In conclusion, many of the identified practices are found to make ecological sense in the context of complex systems and contribute to the resilience of social-ecological systems. The thesis illustrates that the capacity of human-dominated production ecosystems to sustain a flow of desired ecosystem services is strongly associated with local management practices and the governance system that they are embedded in, and that, contrary to what is often assumed, local management can and does add resilience for desired ecosystem services. These findings have substantial policy implications, as insufficient recognition of the dynamics of social-ecological interactions is likely to lead to failure of schemes for human development and biodiversity conservation.
TL;DR: In this paper, the authors studied the effects of road surfaces on the behavior and trail-following abilities of garter snakes (Thamnophis sirtalis parietalis) in Manitoba.
Abstract: If animals avoid road surfaces or are unable to follow conspecific trails across such surfaces, previously continuous populations may be fragmented. We gathered data on the effects of a small (4-m wide) gravel road on the behavior and trail-following abilities of garter snakes (Thamnophis sirtalis parietalis) in Manitoba, central Canada. As expected, the road surface had less vegetation cover, a more open canopy and, thus, higher incident radiation than did the surrounding grassland. Contrary to expectations, however, substrate temperatures were lower on the road than in its surrounds, because of the higher reflectivity of the road's surface. On a nearby asphalt road, substrate temperatures were relatively high on the road surface only in the evening, as surrounding areas cooled. Focal sampling showed that snakes avoided the gravel road, typically changing direction when they encountered it. If they crossed the road, they did so by the shortest possible route (straight across). Mate-searching male snakes were less able to follow substrate-deposited pheromonal trails left by females if those trails crossed a road than if the trails were entirely within the surrounding grassland. Thus, roads may significantly modify snake movement patterns, as well as the ability of males to locate reproductive females. Our study provides the first detailed information on the effects of roads on snake behavior.
TL;DR: In this article, the authors tracked wolf (Canis lupus) movement in the snow for two winters in Jasper National Park, Alberta, Canada to examine how wolves navigate through or around human-use features.
Abstract: Few studies have examined the effects of human development on fine-scale movement behavior, yet understanding animal movement through increasingly human-dominated landscapes is essential for the persistence of many wild populations, especially wary species. In mountainous areas, roads and trails may be particularly deserving of study because they are concentrated in the valley bottoms where they can impede animal movement both across and between valleys. In this study, we tracked wolf (Canis lupus) movement in the snow for two winters in Jasper National Park, Alberta, Canada to examine how wolves navigate through or around human-use features. We quantified the effects of human development and topography on the tortuosity of wolf paths and then tested the permeability of roads, trails, and a railway line to wolf movement by comparing the frequency with which actual wolf paths and a null model of random paths crossed these features. Wolf path tortuosity increased near high-use trails, within areas of high-trail and road density, near predation sites, and in rugged terrain. Wolves crossed all roads, trails, and the railway line 9.7% less often than expected, but avoided crossing high-use roads more than low-use trails. Surprisingly, trails affected movement behavior of wolves equally, if not more, than roads. These results suggest that although roads and trails in this study were not absolute barriers to wolf movement, they altered wolf movements across their territories.
TL;DR: In this paper, resilience is defined consistently with the theoretical uses of the term, in the context of ecosystem models within an application to a simple model of lake eutrophication, demonstrating the usefulness of the operational definition.
Abstract: Multiple stable states or alternative equilibria in ecological systems have been recognized since the 1960s in the ecological literature. Very often, the shift between alternative states occurs suddenly and the resource flows from these systems are modified. Resilience is the capacity of a system to undergo disturbance and maintain its functions and controls. It has multiple levels of meaning, from the metaphorical to the specific. However, most studies that explore resilience-related ideas have used resilience as a metaphor or theoretical construct. In a few cases, it has been defined operationally in the context of a model of a particular system. In this paper, resilience is defined consistently with the theoretical uses of the term, in the context of ecosystem models within an application to a simple model of lake eutrophication. The theoretical definitions of resilience and the characteristics of the operational definition that are necessary for ensuring consistency are reviewed. A mathematical formulation of resilience is built in the framework of the viability theory. This formulation emphasizes the link between resilience and the cost of the recovery after a disturbance. This cost is first chosen in relation to the time of crisis in the application to a model of lake eutrophication. The resilience values are then obtained by numerical integration. For another choice of the cost function, the viability algorithm is needed to compute the resilience values. These applications demonstrate the usefulness of our operational definition.
TL;DR: In this paper, the relationship between urban leaf area, population density, and their interaction with median income and median housing value was investigated in Terre Haute, Indiana, USA.
Abstract: This study examines urban quality of life by assessing the relationship between observed socioeconomic conditions and urban forest amenities in Terre Haute, Indiana, USA. Using remote-sensing methods and techniques, and ordinary least squares regression, the paper determines the relationship between urban leaf area and a population density parameter with median income and median housing value. Results demonstrate positive correlations between urban leaf area, population density, and their interaction with median income and median housing value. Furthermore, leaf area, density, and their interaction statistically account for observed variance in median income and median housing value, indicating that these variables may be used to study observed quality-of-life metrics. The methods used in this study may be useful to city managers, planners, and foresters who are concerned with urban quality-of-life issues, and who are interested in developing and implementing alternative policy assessment regimes.
TL;DR: In this article, simulated changes in the position of the upper treeline in the Swedish mountains in response to predicted climate change were described. But the results showed the treeline advancing upward by 233-667 m, depending on the climate scenario used and location within the mountain chain.
Abstract: Climate change may strongly influence species distribution and, thus, the structure and function of ecosystems. This paper describes simulated changes in the position of the upper treeline in the Swedish mountains in response to predicted climate change. Data on predicted summer temperature changes, the current position of the treeline, and a digital elevation model were used to predict the position of the treeline over a 100-year timeframe. The results show the treeline advancing upward by 233-667 m, depending on the climate scenario used and location within the mountain chain. Such changes hypothetically caused a 75-85% reduction in treeless alpine heaths, with 60-93% of the remaining areas being scree slopes and boulder fields. For this change to occur, the migration rate of the trees would be in the order of 23-221 m yr -1 , which is well within published migration rates for wind-dispersed deciduous trees. The remaining alpine areas would be strongly fragmented. These drastic changes would influence all aspects of mountain ecosystems, including biodiversity conservation and human land-use patterns.
TL;DR: In this paper, the authors compare scientific knowledge and traditional knowledge of the Penan Benalui and other forest product collectors of Indonesian Borneo to identify the complex ecology of resin formation involving two, or maybe three, living organisms (the tree, one or more fungi, and possibly an insect intermediary).
Abstract: Traditional knowledge, promoted to make conservation and development more relevant and socially acceptable, is shown to have an important role in identifying critical research needs in tropical ecology. Botanists, foresters, and phytochemists, among others, from many countries have sought for decades to understand the process of resin formation in the genus Aquilaria, a tropical forest tree of South and Southeast Asia. Not every tree develops the resin and, despite extensive scientific research, this process remains poorly understood. Attempts at cultivating the valuable aromatic resin, gaharu, have been uneven at best. Thus, gaharu remains largely a natural forest product, increasingly under threat as the trees are overexploited and forest is cleared. In this paper, we compare scientific knowledge and traditional knowledge of the Penan Benalui and other forest product collectors of Indonesian Borneo. Although limited management of wildlings failed to bring the resinproducing species under cultivation, we found that the Penan recognize the complex ecology of resin formation involving two, or maybe three, living organisms—the tree, one or more fungi, and possibly an insect intermediary. Developing a sustainable production system for this resource will require a clear understanding of how these various natural elements function, separately and synergistically. Traditional knowledge can help fill gaps in our information base and identify promising areas for future research. Both correspondence and gaps in knowledge support the call for a greater role for ethnobiological research and interdisciplinary cooperation, especially between ethnobiologists and foresters, in developing sustainable management systems for this traditional resource and its natural habitat.
TL;DR: In this article, the impact of different cropping methods on biodiversity along a subjectively determined land-use intensity gradient in southern Sumatra, ranging from primary and secondary forest to coffee-farming systems (simple, complex, with and without shade crops) and smallholder coffee plantings, at increasing levels of intensity.
Abstract: The sustainable management of biodiversity and productivity in forested lands requires an understanding of key interactions between socioeconomic and biophysical factors and their response to environmental change. Appropriate baseline data are rarely available. As part of a broader study on biodiversity and profitability, we examined the impact of different cropping methods on biodiversity (plant species richness) along a subjectively determined land-use intensity gradient in southern Sumatra, ranging from primary and secondary forest to coffee-farming systems (simple, complex, with and without shade crops) and smallholder coffee plantings, at increasing levels of intensity. We used 24 (40 x 5 m) plots to record site physical data, including soil nutrients and soil texture together with vegetation structure, all vascular plant species, and plant functional types (PFTs—readily observable, adaptive, morphological features). Biodiversity was lowest under simple, intensive, non-shaded farming systems and increased progressively through shaded and more complex agroforests to late secondary and closed-canopy forests. The most efficient single indicators of biodiversity and soil nutrient status were PFT richness and a derived measure of plant functional complexity. Vegetation structure, tree dry weight, and duration of the land-use type, to a lesser degree, were also highly correlated with biodiversity. Together with a vegetation, or V index, the close correspondence between these variables and soil nutrients suggests they are potentially useful indicators of coffee production and profitability across different farming systems. These findings provide a unique quantitative basis for a subsequent study of the nexus between biodiversity and profitability.
TL;DR: In this paper, the authors propose an explanation for why overexploitation seems more common in ancient societies that built larger structures based on the well-studied sunk-cost effect in human decision making: decisions are often based on past investments rather than expected future returns.
Abstract: One of the most persistent mysteries in the history of humankind is the collapse of ancient societies. It is puzzling that societies that achieved such high levels of development disappeared so suddenly. It has been argued that overexploitation of environmental resources played a role in the collapse of such societies. In this paper, we propose an explanation why overexploitation seems more common in ancient societies that built larger structures. This explanation is based on the well-studied sunk-cost effect in human decision making: decisions are often based on past investments rather than expected future returns. This leads to an unwillingness to abandon something (e. g., a settlement) if a great deal has been invested in it, even if future prospects are dim. Empirical study suggests that there are indications of sunk-cost effects in the histories of several ancient societies. A stylized model is used to illustrate under which conditions societal collapse may be expected. Finally, we discuss the consequences of these insights for current societies.
TL;DR: This paper provides an example of a practical integration of probabilistic policy analysis and multi- stakeholder decision methods at a hydroelectric facility in British Columbia, Canada and demonstrates the utility of combining expert judgment processes and stakeholder values with adaptive management to improve the likelihood that proposed experimental approaches will deliver net value to society.
Abstract: This paper provides an example of a practical integration of probabilistic policy analysis and multi- stakeholder decision methods at a hydroelectric facility in British Columbia, Canada. A structured decision- making framework utilizing the probabilistic judgments of experts, a decision tree, and a Monte Carlo simulation provided insight to a decision to implement an experimental flow release program. The technical evaluation of the expected costs and benefits of the program were integrated into the multi-stakeholder decision process. The framework assessed the magnitude of the uncertainty, its potential to affect water management decisions, the predictive ability of the experiment, the value of the expected costs and benefits, and the preferences of stakeholders for alternative outcomes. As a result of the analysis, the initial experimental design was revised, and a multi-stakeholder group reached consensus on a program of experimental flow releases to test the response of salmonids to flow. The approach treats adaptive management as a policy alternative within a broader decision problem, and it demonstrates the utility of combining expert judgment processes and stakeholder values with adaptive management to improve the likelihood that proposed experimental approaches will deliver net value to society.
TL;DR: It is likely that shellfish fishing explains at least part of the 40% decline in oystercatcher numbers in recent years, and the unprotected MPAs are effective on a local scale, but not on a global scale.
Abstract: Fisheries and other human activities pose a global threat to the marine environment. Marine protected areas (MPAs) are an emerging tool to cope with such threats. In the Dutch Wadden Sea, large MPAs (covering 31% of all intertidal flats) have been created to protect shellfish-eating birds and allow recovery of important habitats. Even though shellfish fishing is prohibited in these areas, populations of shellfish-eating birds in the Wadden Sea have declined sharply. The role of shellfish fisheries in these declines is hotly debated, therefore, we investigated the effectiveness of MPAs for protecting oystercatcher (Haematopus ostralegus) populations. Shellfish stocks (cockles, Cerastoderma edule) were substantially higher in the MPAs, but surprisingly this has not resulted in a redistribution of wintering oystercatchers. Oystercatchers in unprotected areas had less shellfish in their diet and lower condition (a combined measure of mass and haematological parameters), and their estimated mortality was 43% higher. It is likely, therefore, that shellfish fishing explains at least part of the 40% decline in oystercatcher numbers in recent years. Condition and mortality effects were strongest in males, and the population sex ratio was female biased, in agreement with the fact that males rely more on shellfish. The unprotected areas apparently function as an "ecological trap," because oystercatchers did not respond as anticipated to the artificial spatial heterogeneity in food supply. Consequently, the MPAs are effective on a local scale, but not on a global scale. Similar problems are likely to exist in terrestrial ecosystems, and distribution strategies of target species need to be considered when designing terrestrial and marine protected areas if they are to be effective.