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At the global scale, biodiversity indicators are typically used to monitor general trends, but are rarely implemented with specific purpose or linked directly to decision making. Some indicators are better suited to predicting future change, others are more appropriate for evaluating past actions, but this is seldom made explicit. We developed a conceptual model for assigning biodiversity indicators to appropriate functions based on a common approach used in economics. Using the model, indicators can be classified as leading (indicators that change before the subject of interest, informing preventative actions), coincident (indicators that measure the subject of interest), or lagging (indicators that change after the subject of interest has changed and thus can be used to evaluate past actions). We classified indicators based on ecological theory on biodiversity response times and management objectives in 2 case studies: global species extinction and marine ecosystem collapse. For global species extinctions, indicators of abundance (e.g., the Living Planet Index or biodiversity intactness index) were most likely to respond first, as leading indicators that inform preventative action, while extinction indicators were expected to respond slowly, acting as lagging indicators flagging the need for evaluation. For marine ecosystem collapse, indicators of direct responses to fishing were expected to be leading, while those measuring ecosystem collapse could be lagging. Classification defines an active role for indicators within the policy cycle, creates an explicit link to preventative decision-making, and supports preventative action.Alineamiento entre los Indicadores de Biodiversidad y los Requerimientos Políticos Resumen En la escala global, los indicadores de biodiversidad se usan comúnmente para monitorear las tendencias generales pero rara vez se implementan con un propósito específico o vinculados directamente con la toma de decisiones. Algunos indicadores son mejores para predecir los cambios futuros, mientras que otros son más apropiados para la evaluación de acciones pasadas, aunque lo anterior casi nunca se comunica explícitamente. Desarrollamos un modelo conceptual para la atribución de indicadores de biodiversidad a funciones apropiadas con base en una estrategia común que se usa en la economía. Con este modelo, los indicadores pueden clasificarse como principales (indicadores que cambian antes que el sujeto de interés, orientando así las acciones preventivas), coincidentes (indicadores que miden al sujeto de interés) o rezagados (indicadores que cambian después de que el sujeto de interés ha cambiado y por lo tanto puede usarse para evaluar las acciones pasadas). Clasificamos los indicadores con base en la teoría ecológica sobre los tiempos de respuesta de la biodiversidad y los objetivos de manejo en dos estudios de caso: la extinción mundial de especies y el colapso de los ecosistemas marinos. Para la extinción mundial de especies, los indicadores de abundancia (p. ej.: el Índice del Planeta Viviente o el índice de biodiversidad intacta) fueron los más probables en tener una respuesta pronta como indicadores principales que orientan las acciones preventivas, mientras que se esperó que los indicadores de extinción tuvieran respuestas lentas, por lo que actuarían como indicadores rezagados que disminuyeron la necesidad de evaluación. Para el colapso de los ecosistemas marinos, se anticipó que los indicadores de las respuestas directas a la pesca fueran los indicadores principales, mientras que aquellos que miden el colapso del ecosistema podrían ser indicadores rezagados. La clasificación define un papel activo para los indicadores dentro del ciclo de políticas, crea un vínculo explícito con la toma de decisiones preventivas y respalda la acción preventiva.在全球范围内, 生物多样性指标常常用于监测整体趋势, 但很少有具体实施目的或直接与决策挂钩。有些指标更适合预测未来的变化, 有些指标则更适合评价过去的行动, 但这一点很少得到说明。基于经济学中的常用方法, 我们开发了一个根据恰当功能分配生物多样性指标的概念模型。该模型将指标分为领先指标 (先于研究主体发生变化的指标, 可为预防性行动提供信息) 、同步指标 (度量研究主体的指标) 及滞后指标 (研究主体变化后才发生变化的指标, 可用于评估过去的行动) 。我们以全球物种灭绝和海洋生态系统崩溃作为案例, 根据生物多样性响应时间的生态学理论和管理目标对相应指标进行了分类。在全球物种灭绝的案例中, 种群数量指标 (如地球生命力指数或生物多样性完整性指数) 最有可能首先产生响应, 它们是可以为预防行动提供信息的领先指标, 而灭绝相关的指标预期响应缓慢, 则是表明评估需求的滞后指标。对于海洋生态系统崩溃而言, 衡量对渔业直接响应的指标应为领先指标, 而生态系统崩溃的相关指标可能为滞后指标。对指标的分类确定了其在政策周期中的积极作用, 建立了指标与预防性决策的明确联系, 并支持了预防性行动。【翻译: 胡怡思; 审校: 聂永刚】.

When evaluating the impact of a biodiversity conservation intervention, a counterfactual is typically needed. Counterfactuals are possible alternative system trajectories in the absence of an intervention. Comparing observed outcomes against the chosen counterfactual allows the impact (change attributable to the intervention) to be determined. Because counterfactuals by definition never occur, they must be estimated. Sometimes, there may be many plausible counterfactuals, including various drivers of biodiversity change and defined on a range of spatial or temporal scales. Here, we posit that, by definition, conservation interventions always take place in social-ecological systems (SES) (i.e., ecological systems integrated with human actors). Evaluating the impact of an intervention in an SES, therefore, means taking into account the counterfactuals assumed by different human actors. Use of different counterfactuals by different actors will give rise to perceived differences in the impacts of interventions, which may lead to disagreement about its success or the effectiveness of the underlying approach. Despite that there are biophysical biodiversity trends, it is often true that no single counterfactual is definitively the right one for conservation assessment, so multiple evaluations of intervention efficacy could be considered justifiable. Therefore, we propose calculating the sum of perceived differences, which captures the range of impact estimates associated with different actors in a given SES. The sum of perceived differences gives some indication of how closely actors in an SES agree on the impacts of an intervention. We applied the concept of perceived differences to a set of global, national, and regional case studies (e.g., global realization of Aichi Target 11 for marine protected areas, effect of biodiversity offsetting on vegetation condition in Australia, and influence of conservation measures on an endangered ungulate in Central Asia). We explored approaches for minimizing the sum, including a combination of negotiation and structured decision making, careful alignment of expectations on scope and measurement, and explicit recognition of any intractable differences between stakeholders.Reconciliación de Múltiples Hipótesis de Contraste al Evaluar el Impacto de la Conservación de la Biodiversidad en los Sistemas Socio-Ecológicos Resumen Cuando se evalúa el impacto de una intervención de conservación de la biodiversidad, generalmente se requiere una hipótesis de contraste. Las hipótesis de contraste son las posibles trayectorias alternativas del sistema en ausencia de una intervención. La comparación de los resultados observados con la hipótesis de contraste elegida permite que se determine el impacto (cambio atribuible a la intervención). Ya que las hipótesis de contraste por definición nunca ocurren, éstas deben ser estimadas. En algunos casos es posible que existan muchas hipótesis de contraste, incluyendo a muchos conductores del cambio en la biodiversidad, y que estén definidas bajo una gama de escalas espaciales o temporales. En este artículo planteamos que, por definición, las intervenciones de conservación siempre ocurren en sistemas socioecológicos (SES) (es decir, sistemas ecológicos integrados con actores humanos). Por lo tanto, la evaluación del impacto de una intervención en un SES implica la consideración de las hipótesis de contraste asumidas por los diferentes actores humanos. El uso de diferentes hipótesis de contraste por los diferentes actores hará que surjan diferencias percibidas en los impactos de las intervenciones, lo que puede llegar a discrepancias sobre su éxito o sobre la efectividad de la estrategia subyacente. A pesar de que existen tendencias biofísicas de la biodiversidad, con frecuencia es cierto que no hay una sola hipótesis de contraste que sea correcta de manera definitiva para la evaluación de la conservación, por lo que múltiples evaluaciones de la eficiencia de la intervención podrían considerarse como justificables. Así, proponemos que se calcule la suma de las diferencias percibidas, la cual captura la gama de las estimaciones de impacto asociadas con diferentes actores en un SES dado. La suma de las diferencias percibidas nos da algún tipo de indicación sobre cuán de acuerdo están los actores de un SES sobre los impactos de una intervención. Aplicamos el concepto de diferencias percibidas a un conjunto de estudios de caso mundiales, nacionales y regionales (p. ej.: la realización mundial del Objetivo Aichi 11 para las áreas marinas protegidas, el efecto de la compensación de la biodiversidad sobre las condiciones botánicas en Australia y la influencia de las medidas de conservación sobre un ungulado en peligro en Asia central). Exploramos las estrategias para minimizar la suma, incluyendo una combinación de negociación y toma estructurada de decisiones, la alineación cuidadosa de las expectativas sobre el enfoque y la medida y el reconocimiento explícito de cualquier diferencia intratable entre los actores sociales.在评估生物多样性保护干预措施的影响时, 通常需要一个反设事实。反设事实是在没有干预的情况下可能的替代性系统轨迹。将观察到的结果与选择的反设事实进行比较, 则可以确定影响 (干预引起的变化) 。由于从定义上讲, 反设事实永远不会发生, 因此必须对其进行估计。然而, 有时可能存在许多看似合理的反设事实, 包括生物多样性变化的各种驱动因素, 并且可以在不同的时空尺度范围内加以定义。本研究假定, 根据定义, 保护干预总是发生在社会生态系统中 (即生态系统与人类行为相结合) 。因此, 评估一项干预措施对社会生态系统的影响需要考虑不同人类行为的反设事实。针对不同行动者使用不同的反设事实, 会导致干预措施的影响也出现明显差异, 这可能使人们对干预成功与否或方法有效性的评估产生分歧。虽然存在生物物理上的生物多样性趋势, 但往往没有单一的反设事实在保护评估中绝对适用, 因此应当对干预效果进行多重评估。我们建议计算可观测的差异的总和, 这样可以包含既定社会生态系统中不同行动者的影响估计范围。观测差异的总和还可以在一定程度上表明社会生态系统中的行动者对干预影响的一致性。我们将观测差异的概念应用于一系列全球、国家和区域的案例研究中 (如爱知目标 11 中海洋保护区的全球实现情况、澳大利亚生物多样性补偿对植被的影响, 以及中亚的保护措施对一种濒危有蹄类动物的影响)。本研究进一步探索了使观测总差异最小化的方法, 包括结合协商与结构化决策, 仔细调整对影响范围和测定结果的期望, 以及清楚认识到利益相关者之间难以处理的差异。【翻译: 胡怡思; 审校: 聂永刚】.

Carnivore predation on livestock is a complex management and policy challenge, yet it is also intrinsically an ecological interaction between predators and prey. Human-wildlife interactions occur in socioecological systems in which human and environmental processes are closely linked. However, underlying human-wildlife conflict and key to unpacking its complexity are concrete and identifiable ecological mechanisms that lead to predation events. To better understand how ecological theory accords with interactions between wild predators and domestic prey, we developed a framework to describe ecological drivers of predation on livestock. We based this framework on foundational ecological theory and current research on interactions between predators and domestic prey. We used this framework to examine ecological mechanisms (e.g., density-mediated effects, behaviorally mediated effects, and optimal foraging theory) through which specific management interventions operate, and we analyzed the ecological determinants of failure and success of management interventions in 3 case studies: snow leopards (Panthera uncia), wolves (Canis lupus), and cougars (Puma concolor). The varied, context-dependent successes and failures of the management interventions in these case studies demonstrated the utility of using an ecological framework to ground research and management of carnivore-livestock conflict. Mitigation of human-wildlife conflict appears to require an understanding of how fundamental ecological theories work within domestic predator-prey systems.Un Marco de Trabajo Ecológico para Contextualizar el Conflicto Carnívoro - Ganado Resumen La depredación del ganado por carnívoros es un reto complejo para el manejo y las políticas, a pesar de que es intrínsecamente una interacción ecológica entre depredadores y presas. Las interacciones entre humanos y la fauna ocurren en sistemas socio-ecológicos en los que los humanos y los procesos ambientales están conectados estrechamente. Sin embargo, el conflicto humano - fauna subyacente y la clave para desenredar su complejidad son mecanismos ecológicos complejos e identificables que resultan en eventos de depredación. Para tener un mejor entendimiento sobre cómo la teoría ecológica armoniza con las interacciones entre los depredadores silvestres y la presa doméstica, desarrollamos un marco de trabajo para describir las causantes ecológicas de la depredación del ganado. Basamos este marco de trabajo en las principales teorías ecológicas y las investigaciones actuales sobre las interacciones entre los depredadores y las presas domésticas. Usamos este marco de trabajo para examinar los mecanismos ecológicos (es decir, los efectos mediados por la densidad, los efectos mediados por el comportamiento, y la teoría del forrajeo óptimo) mediante los cuales operan ciertas intervenciones específicas de manejo y analizamos las determinantes ecológicas del fracaso y el éxito de las intervenciones de manejo en tres estudios de caso: el leopardo de las nieves (Panthera uncia), el lobo (Canis lupus), y el puma (Puma concolor). Los éxitos y fracasos variados y dependientes del contexto que sufrieron las intervenciones de manejo en estos estudios de caso demostraron la utilidad del uso de un marco de trabajo ecológico para aterrizar la investigación y el manejo del conflicto carnívoro - ganado. La mitigación del conflicto humano - fauna parece requerir de un entendimiento sobre cómo funcionan las teorías ecológicas fundamentales dentro del sistema doméstico depredador - presa.食肉动物对家畜的捕食是管理和政策上面临的一项复杂挑战, 但它本质上也是捕食者和猎物的生态互作问题。人兽互作发生在人类与环境过程紧密联系的社会生态系统中; 然而, 人兽冲突及揭示其复杂性的本质则是导致捕食事件发生的、具体明确的生态学机制。为了更好地理解生态学理论如何反映野生捕食者和家养猎物之间的互作, 我们开发了一个框架来描述捕食家畜的生态驱动力。这个框架基于基础生态学理论和捕食者与家养猎物互作的研究现状。我们用这个框架分析了采取特定管理干预措施所依赖的生态学机制 (如密度调控作用、行为调控作用和最优觅食理论), 并对决定管理干预成败与否的生态学因素进行了三个案例分析, 分别涉及雪豹 (Panthera uncia) 、灰狼 (Canis lupus) 和美洲狮 (Puma concolor) 。这些案例中管理干预的成败取决于具体情境, 这显示了我们的生态框架在开展食肉动物与家畜冲突的研究和管理中的有效性。我们认为, 减缓人兽冲突需要了解基础生态学理论在捕食者-家养猎物系统中的作用原理。 【翻译: 胡怡思; 审校: 聂永刚】.

Conservation biology was founded on the idea that efforts to save nature depend on a scientific understanding of how it works. It sought to apply ecological principles to conservation problems. We investigated whether the relationship between these fields has changed over time through machine reading the full texts of 32,000 research articles published in 16 ecology and conservation biology journals. We examined changes in research topics in both fields and how the fields have evolved from 2000 to 2014. As conservation biology matured, its focus shifted from ecology to social and political aspects of conservation. The 2 fields diverged and now occupy distinct niches in modern science. We hypothesize this pattern resulted from increasing recognition that social, economic, and political factors are critical for successful conservation and possibly from rising skepticism about the relevance of contemporary ecological theory to practical conservation., Article impact statement: Quantitative literature evaluation reveals that the research topics of ecology and conservation biology are drawing apart.

Over the past decades, much research has focused on understanding the critical factors for marine extinctions with the aim of preventing further species losses in the oceans. Although conservation and management strategies are enabling several species and populations to recover, others remain at low abundance levels or experience further declines. To understand these discrepancies, we asked which intrinsic and extrinsic factors are critical for the recovery of marine mammals. Building on a published database on abundance trends of 137 marine mammal populations worldwide, we compiled data on 28 potential critical factors and used random forests and additive mixed models in our analytical approach. Our results highlight that a mix of life-history characteristics, ecological traits, phylogenetic relatedness, population size, geographic range, human impacts and management efforts were important in explaining why populations recover or not. Generally, species with lower age at maturity and intermediate habitat area were more likely to recover, which is consistent with life-history and ecological theory. Body size and ocean basin were also important, as well as trophic level, social interactions, the dominant habitat and habitat disturbance. Overall, our results highlight that not one or two, but a range of intrinsic and extrinsic factors are important for recovery, pointing to cumulative effects. This new line of research provides important information for improving conservation and management strategies particularly for those populations that have been unable to recover to date. This article is protected by copyright. All rights reserved

One of the key determinants of success in biodiversity conservation is how well conservation planning decisions account for the social system in which actions are to be implemented. Understanding elements of how the social and ecological systems interact can help identify opportunities for implementation. Utilizing data from a large-scale conservation initiative in southwestern of Australia, we explored how a social-ecological system framework can be applied to identify how social and ecological factors interact to influence the opportunities for conservation. Using data from semistructured interviews, an online survey, and publicly available data, we developed a conceptual model of the social-ecological system associated with the conservation of the Fitz-Stirling region. We used this model to identify the relevant variables (remnants of vegetation, stakeholder presence, collaboration between stakeholders, and their scale of management) that affect the implementation of conservation actions in the region. We combined measures for these variables to ascertain how areas associated with different levels of ecological importance coincided with areas associated with different levels of stakeholder presence, stakeholder collaboration, and scales of management. We identified areas that could benefit from different implementation strategies, from those suitable for immediate conservation action to areas requiring implementation over the long term to increase on-the-ground capacity and identify mechanisms to incentivize implementation. The application of a social-ecological framework can help conservation planners and practitioners facilitate the integration of ecological and social data to inform the translation of priorities for action into implementation strategies that account for the complexities of conservation problems in a focused way.

Ecological systems often operate on time scales significantly longer or shorter than the time scales typical of human decision making, which causes substantial difficulty for conservation and management in socioecological systems. For example, invasive species may move faster than humans can diagnose problems and initiate solutions, and climate systems may exhibit long-term inertia and short-term fluctuations that obscure learning about the efficacy of management efforts in many ecological systems. We adopted a management-decision framework that distinguishes decision makers within public institutions from individual actors within the social system, calls attention to the ways socioecological systems respond to decision makers' actions, and notes institutional learning that accrues from observing these responses. We used this framework, along with insights from bedeviling conservation problems, to create a typology that identifies problematic time-scale mismatches occurring between individual decision makers in public institutions and between individual actors in the social or ecological system. We also considered solutions that involve modifying human perception and behavior at the individual level as a means of resolving these problematic mismatches. The potential solutions are derived from the behavioral economics and psychology literature on temporal challenges in decision making, such as the human tendency to discount future outcomes at irrationally high rates. These solutions range from framing environmental decisions to enhance the salience of long-term consequences, to using structured decision processes that make time scales of actions and consequences more explicit, to structural solutions aimed at altering the consequences of short-sighted behavior to make it less appealing. Additional application of these tools and long-term evaluation measures that assess not just behavioral changes but also associated changes in ecological systems are needed.

Most conservation planning to date has focused on protecting today's biodiversity with the assumption that it will be tomorrow's biodiversity. However, modern climate change has already resulted in distributional shifts of some species and is projected to result in many more shifts in the coming decades. As species redistribute and biotic communities reorganize, conservation plans based on current patterns of biodiversity may fail to adequately protect species in the future. One approach for addressing this issue is to focus on conserving a range of abiotic conditions in the conservation-planning process. By doing so, it may be possible to conserve an abiotically diverse "stage" upon which evolution will play out and support many actors (biodiversity). We reviewed the fundamental underpinnings of the concept of conserving the abiotic stage, starting with the early observations of von Humboldt, who mapped the concordance of abiotic conditions and vegetation, and progressing to the concept of the ecological niche. We discuss challenges posed by issues of spatial and temporal scale, the role of biotic drivers of species distributions, and latitudinal and topographic variation in relationships between climate and landform. For example, abiotic conditions are not static, but change through time-albeit at different and often relatively slow rates. In some places, biotic interactions play a substantial role in structuring patterns of biodiversity, meaning that patterns of biodiversity may be less tightly linked to the abiotic stage. Furthermore, abiotic drivers of biodiversity can change with latitude and topographic position, meaning that the abiotic stage may need to be defined differently in different places. We conclude that protecting a diversity of abiotic conditions will likely best conserve biodiversity into the future in places where abiotic drivers of species distributions are strong relative to biotic drivers, where the diversity of abiotic settings will be conserved through time, and where connectivity allows for movement among areas providing different abiotic conditions.

Robust ways to meet objectives of environmental conservation and social and economic development remain elusive. This struggle may in part be related to insufficient understanding of the feedbacks between conservation initiatives and social-ecological systems, specifically, the ways in which conservation initiatives result in social changes that have secondary effects on the environments targeted by conservation. To explore this idea we sampled peer-reviewed articles addressing the social and environmental dimensions of conservation and coded each paper according to its research focus and characterization of these feedbacks. The majority of articles in our sample focused either on the effect of conservation initiatives on people (e.g., relocation, employment) or the effect of people on the environment (e.g., fragmentation, conservation efficacy of traditional management systems). Few studies in our sample empirically addressed both the social dynamics resulting from conservation initiatives and subsequent environmental effects. In many cases, one was measured and the other was discussed anecdotally. Among the studies that describe feedbacks between social and environmental variables, there was more evidence of positive (amplifying) feedbacks between social and environmental outcomes (i.e., undesirable social outcomes yielded undesirable environmental effects, and desirable social outcomes yielded desirable environmental effects). The major themes within the sampled literature include conflict between humans and wild animals, social movements, adaptive comanagement, loss of traditional management systems, traditional ecological knowledge, human displacement and risks to livelihoods, and conservation and development. The narratives associated with each theme can serve as hypotheses for facilitating further discussion about conservation issues and for catalyzing future studies of the feedbacks between conservation and social-ecological systems.

Conservation biology has provided wildlife managers with a wealth of concepts and tools for use in conservation planning; among them is the surrogate species concept. Over the past 20 years, a growing body of empirical literature has demonstrated the limited effectiveness of surrogates as management tools, unless it is first established that the target species and surrogate will respond similarly to a given set of environmental conditions. Wildlife managers and policy makers have adopted the surrogate species concept, reflecting the limited information available on most species at risk of extirpation or extinction and constraints on resources available to support conservation efforts. We examined the use of surrogate species, in the form of cross-tax on response-indicator species (that is, one species from which data are used to guide management planning for another, distinct species) in the Sacramento-San Joaquin Delta, California (U.S.A.). In that system there has been increasing reliance on surrogates in conservation planning for species listed under federal or state endangered species acts, although the agencies applying the surrogate species concept did not first validate that the surrogate and target species respond similarly to relevant environmental conditions. During the same period, conservation biologists demonstrated that the surrogate concept is generally unsupported by ecological theory and empirical evidence. Recently developed validation procedures may allow for the productive use of surrogates in conservation planning, but, used without validation, the surrogate species concept is not a reliable planning tool.

The Ministerial Declaration made at the World Summit on Sustainable Development in Johannesburg agreed to protection and restoration of the integrity of our planet's ecological systems and identified as a major priority a significant reduction in the rate of current biodiversity loss at national and global levels. This goal is essentially a reformulation of that of the Convention on Biological Diversity agreed to in Rio de Janeiro 10 years ago. For us to have any idea of where we are in relation to this goal, we need information on current global trends in the status of natural systems. By 2005 it is envisaged that the Millennium Ecosystem Assessment (MA) will have provided a comprehensive account of global biodiversity from a compilation of existing data, but that is a long time to wait. What can we say now about trends in the state of wild nature since the United Nations' 1992 Conference on Environment and Development in Rio de Janeiro? Here, we briefly review recent global trends in habitat area in as many broadly defined natural habitats as possible and in indices of animal populations characteristic of those habitats. The information available indicates continuing declines in habitat area and species, but that data are extremely sparse.

Global climate change is frequently considered a major conservation threat. The Earth's climate has already warmed by 0.5 8 C over the past century, and recent studies show that it is possible to detect the ef- fects of a changing climate on ecological systems. This suggests that global change may be a current and fu- ture conservation threat. Changes in recent decades are apparent at all levels of ecological organization: pop- ulation and life-history changes, shifts in geographic range, changes in species composition of communities, and changes in the structure and functioning of ecosystems. These ecological effects can be linked to recent population declines and to both local and global extinctions of species. Although it is impossible to prove that climate change is the cause of these ecological effects, these findings have important implications for conser- vation biology. It is no longer safe to assume that all of a species' historic range remains suitable. In drawing attention to the importance of climate change as a current threat to species, these studies emphasize the need for current conservation efforts to consider climate change in both in situ conservation and reintroduction efforts. Additional threats will emerge as climate continues to change, especially as climate interacts with other stressors such as habitat fragmentation. These studies can contribute to preparations for future chal- lenges by providing valuable input to models and direct examples of how species respond to climate change.

The debate over the objectives and methods of ecosystem management has been confusing, in part because people truly mean different things when they use the term ecosystem management. These different meanings reflect differences in interests, values, and knowledge. I organized these meanings into three sets: "environmentally sensitive multiple use," an "ecosystem approach to resource management," and "ecore- gional management." Environmentally sensitive multiple use takes an anthropocentric perspective that seeks to foster multiple human uses subject to an understanding of environmental constraints that goes beyond that considered in traditional multiple-use management. An ecosystem approach incorporates a biocentric view in which ecosystems are understood as a metaphor for holistic thinking requiring an expanded consid- eration of the dynamism and complexity of ecological systems, scale phenomena, and the need for manage- ment across ownership boundaries. Ecoregional management takes an ecocentric perspective that focuses on the management of specific landscape ecosystems defined as real geographic spaces and that shifts manage- ment focus toward ecosystem processes and away from biota. Understanding these three conceptualizations as different points along a continuum of resource management paradigms helps clarify the different visions of ecosystem management held by different groups. Because different places and groups are at various points on the continuum, progress comes from moving along the continuum and not necessarily by seeking a single state called "ecosystem management." Policy prescriptions, such as changes in law, incentives, and informa- tion provision, can be targeted more effectively to the realities of different settings. Ultimately, the conceptual- ization suggests that heterogeneity of ecosystem management approaches is desirable, as long as we learn from the diverse experiences that result. Tres Caras del Manejo de Ecosistemas

The impact of global climatic change on ecological systems has been identified as one of the major themes of ecology over the coming decades (Lubchenco et al. 1991). Already, a considerable body of research has examined possible results of climatological changes on community and population structure (Peters & Lovejoy 1992). Much of the discussion of terrestrial vertebrate communities has suggested changes in composition of the floristic community as the factor driving faunal community change. Most of the remaining research has considered changes resulting from shifting food sources or physiological responses to temperature change (for examples, see Dawson 1992; Rubenstein 1992). Although these explanations should remain priorities for research in global change, we present the differential use of drought-induced cracks in the soil as burrows or refuges for small mammals as an example of the effects that climate-initiated structural changes in the abiotic environment may have on vertebrate communities. We contend that this is an example of an effect that is not considered in coarse-scale models of climatic change, yet

More than 50 years have passed since Aldo Leopold (1933) captured the essence of the conservation movement in his essay "The Conservation Ethic" in the Journal of Forestry. In this essay, Leopold identified a consciousness that "the destruction of land, and the living things upon it, is wrong" and called upon those concerned to "prevent the deterioration of environment." In so doing, Leopold recognized that proper management of natural resources requires knowledge of ecological systems beyond timber, game, and forage. He criticized the status quo and exhorted ecological researchers to "apply [their] findings to land, and to encourage [their] neighbor[s] to do likewise." "Given, then, the knowledge and the desire," he said, "this idea of controlled wild culture or 'management' can be applied not only to quail and trout, but to any living thing from bloodroots to Bell's vireos." In 1933, Leopold clearly recognized the critical link between ecological research and responsible natural resource management. In 1980, the publication of Conservation Biology (Soule & Wilcox 1980) marked a formal reaffirmation of