Aim Current weaknesses of diversity theory include: a failure to distinguish different biogeographical response variables under the general heading of diversity; and a general failure of ecological theory to deal adequately with geographical scale. Our aim is to articulate the case for a top‐down approach to theory building, in which scale is addressed explicitly and in which different response variables are clearly distinguished. Location The article draws upon both theoretical contributions and empirical analyses from all latitudes, focusing on terrestrial ecosystems and with some bias towards (woody) plants. Methods We review current diversity theory and terminology in relation to scale of applicability. As a starting point in developing a general theory, we take the issue of geographical gradients in species richness as a main theme and evaluate the extent to which commonly cited theories are likely to operate at scales from the macro down to the local. Results A degree of confusion surrounds the use of the terms alpha, beta and gamma diversity, and the terms local, landscape and macro‐scale are preferred here as a more intuitive framework. The distinction between inventory and differentiation diversity is highlighted as important as, in terms of scale of analysis, are the concepts of focus and extent. The importance of holding area constant in analysis is stressed, as is the notion that different environmental factors exhibit measurable heterogeneity at different scales. Evaluation of several of the most common diversity theories put forward for the grand clines in species richness, indicates that they can be collapsed to dynamic hypotheses based on climate or historical explanations. The importance of the many ecological/biological mechanisms that have been proposed is evident mainly at local scales of analysis, whilst at the macro‐scale they are dependent largely upon climatic controls for their operation. Local communities have often been found not to be saturated, i.e. to be non‐equilibrial. This is argued, perhaps counter‐intuitively, to be entirely compatible with the persistence through time of macro‐scale patterns of richness that are climatically determined. The review also incorporates recent developments in macroecology, Rapoport’s rule, trade‐offs, and the importance of isolation, landscape impedance and geometric constraints on richness (the mid‐domain effect) in generating richness patterns; highlighting those phenomena that are contributory to the first‐order climatic pattern, and those, such as the geometric constraints, that may confound or obscure these patterns. Main conclusions A general theory of diversity must necessarily cover many disparate phenomena, at various scales of analysis, and cannot therefore be expressed in a simple formula, but individual elements of this general theory may be. In particular, it appears possible to capture in a dynamic climate‐based model and ‘capacity rule’, the form of the grand cline in richness of woody plants at the macro‐scale. This provides a starti...

The human impact on life on Earth has increased sharply since the 1970s, driven by the demands of a growing population with rising average per capita income. Nature is currently supplying more materials than ever before, but this has come at the high cost of unprecedented global declines in the extent and integrity of ecosystems, distinctness of local ecological communities, abundance and number of wild species, and the number of local domesticated varieties. Such changes reduce vital benefits that people receive from nature and threaten the quality of life of future generations. Both the benefits of an expanding economy and the costs of reducing nature’s benefits are unequally distributed. The fabric of life on which we all depend—nature and its contributions to people—is unravelling rapidly. Despite the severity of the threats and lack of enough progress in tackling them to date, opportunities exist to change future trajectories through transformative action. Such action must begin immediately, however, and address the root economic, social, and technological causes of nature’s deterioration.

There is general agreement among scientists that biodiversity is under assault on a global basis and that species are being lost at a greatly enhanced rate. This article examines the role played by biogeographical science in the emergence of conservation guidance and makes the case for the recognition of Conservation Biogeography as a key subfield of conservation biology delimited as: the application of biogeographical principles, theories, and analyses, being those concerned with the distributional dynamics of taxa individually and collectively, to problems concerning the conservation of biodiversity. Conservation biogeography thus encompasses both a substantial body of theory and analysis, and some of the most prominent planning frameworks used in conservation. Considerable advances in conservation guidelines have been made over the last few decades by applying biogeographical methods and principles. Herein we provide a critical review focussed on the sensitivity to assumptions inherent in the applications we examine. In particular, we focus on four inter-related factors: (i) scale dependency (both spatial and temporal); (ii) inadequacies in taxonomic and distributional data (the so-called Linnean and Wallacean shortfalls); (iii) effects of model structure and parameterisation; and (iv) inadequacies of theory. These generic problems are illustrated by reference to studies ranging from the application of historical biogeography, through island biogeography, and complementarity analyses to bioclimatic envelope modelling. There is a great deal of uncertainty inherent in predictive analyses in conservation biogeography and this area in particular presents considerable challenges.Protected area planning frameworks and their resulting map outputs are amongst the most powerful and influential applications within conservation biogeography, and at the global scale are characterised by the production, by a small number of prominent NGOs, of bespoke schemes, which serve both to mobilise funds and channel efforts in a highly targeted fashion. We provide a simple typology of protected area planning frameworks, with particular reference to the global scale, and provide a brief critique of some of their strengths and weaknesses. Finally, we discuss the importance, especially at regional scales, of developing more responsive analyses and models that integrate pattern (the compositionalist approach) and processes (the functionalist approach) such as range collapse and climate change, again noting the sensitivity of outcomes to starting assumptions. We make the case for the greater engagement of the biogeographical community in a programme of evaluation and refinement of all such schemes to test their robustness and their sensitivity to alternative conservation priorities and goals.

Here we present a novel, empirical approach to assess the relative sensitivity of ecosystems to climate variability, one property of resilience that builds on theoretical modelling work recognizing that systems closer to critical thresholds respond more sensitively to external perturbations 2 . We develop a new metric, the vegetation sensitivity index (VSI) which identifies areas sensitive to climate variability over the past 14 years. The metric uses time series data of MODIS-derived enhanced vegetation index (EVI) 3and three climatic variables that drive vegetation productivity 4 (air temperature, water availability and cloud cover). Underlying the analysis is an autoregressive modelling approach used to identify climate drivers of vegetation productivity on monthly timescales, in addition to regions with memory effects and reduced response rates to external forcing 5 . We find ecologically sensitive regions with amplified responses to climate variability in the arctic tundra, parts of the boreal forest belt, the tropical rainforest, alpine regions worldwide, steppe and prairie regions of central Asia and North and South America, the Caatinga deciduous forest in eastern South America, and eastern areas of Australia. Our study provides a quantitative methodology for assessing the relative response rate of ecosystems-be they natural or with a strong anthropogenic signature-to environmental variability, which is the first step toward addressing why some regions appear to be more sensitive than others and what impact this has upon the resilience of ecosystem service provision and human well-being.The rate and scale of projected climate changes in the 21st century are likely to have profound impacts on the functioning of Earth's ecosystems 6 . Much current understanding of how biodiversity will respond to climate change is based on responses to changes in mean Publisher: NPG; Journal: Nature: Nature; Article Type: Biology letter DOI: 10.1038/nature16986Page 2 of 25 climate state 7 . However, climate variability, and the related increases in extreme events in a warmer world 8 , has a strong influence on both the structuring and functioning of ecosystems [9][10][11] . Given the importance of identifying ecologically sensitive areas for ecosystem service provision and poverty alleviation 1 , a key knowledge gap exists in how to identify and then prioritize those regions that are most sensitive to climatic variability.Ecosystem response to variability in external forcing is a key component of resilience.Theory indicates that systems with lower resilience (that is, those with a high probability of crossing a threshold to an alternative state 12 ) experience amplified responses to disturbance and are more sensitive to environmental perturbations 2 . In addition, slower responses (identified through increased autocorrelation) may be evidence of reduced recovery rates in systems approaching critical transitions 13 . Therefore, identification of areas with high ecological sensitivity or reduced recovery rates is an importan...

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