Plant functional trait change across a warming tundra biomeThe tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature-trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming. Environment-trait relationships across the tundra biomeWe found strong spatial associations between temperature and community height, SLA and LDMC (Fig. 2a, Extended Data Fig. 2 and Supplementary Table 3) across the 117 survey sites. Both height and SLA increased with summer temperature, but the temperaturetrait relationship for SLA was much stronger at wetter than at drier sites. LDMC was negatively related to temperature, and

2016-12-23T18:52:10

Nations around the world are required to measure their progress towards key biodiversity goals. One important example of this, the Convention on Biological Diversity's 2010 target, is soon approaching. The target set is to significantly reduce the rate of biodiversity loss by the year 2010. However, to what extent are the data, especially for tropical countries, available to indicate biodiversity change and to what extent is current knowledge of biodiversity change truly a global picture? While species richness is greatest in the tropics, biodiversity data richness is skewed towards the poles. This not only provides a significant challenge for global indicators to accurately represent biodiversity, but also for individual countries that are responsible under such legislation for measuring their own impact on biodiversity. We examine the coverage of biodiversity data using four global biodiversity datasets, and look at how effective current efforts are at addressing this discrepancy, and what countries might be able to do in time for 2010 and beyond. We conclude by suggesting a number of activities which might provide impetus for improved biodiversity monitoring in tropical nations.Keywords: biodiversity monitoring; threatened species; population decline; Convention on Biological Diversity; indicators for 2010 Target Résumé Toutes les nations sont tenues de mesurer les progrès réalisés au regard des législations clés sur la biodiversité. Un exemple important de ceci, à savoir l'atteinte des objectifs de 2010 définis par la Convention sur la Diversité Biologique, approche à grands pas. Cependant, dans quelles mesures les données collectées, particulièrement pour les pays tropicaux, sont-elles suffisantes pour indiquer des changements de la biodiversité, et dans quelles mesures la connaissance actuelle des changements de la biodiversité donne-t-elle une vision globale des changements en cours? Bien que la richesse spécifique soit plus importante sous les tropiques, les données collectées quand au nombre d'espèces présentes sont plus importantes vers les pôles. Ceci représente non seulement un défi majeur en terme de production d'indicateurs globaux capables de représenter avec précision la diversité biologique, mais également un défi majeur pour les pays ayant la responsabilité de mesurer leur impact sur la biodiversité, et ceci en vertu des législations précédemment citées. Nous avons examiné la couverture spatiale des données sur la biodiversité au moyen de quatre jeux de données sur la biodiversité mondiale, et exploré si les efforts actuels visant à remédier à cette incohérence sont efficaces. Nous avons également identifié les pays qui pourraient être en mesure de mesurer leur impact sur la biodiversité à temps pour 2010, et au-delà. Nous concluons cette étude en suggérant un certain nombre d'activités qui pourraient améliorer le suivi de la biodiversité dans les pays tropicaux.

The potential for conservation of individual species has been greatly advanced by the International Union for Conservation of Nature's (IUCN) development of objective, repeatable, and transparent criteria for assessing extinction risk that explicitly separate risk assessment from priority setting. At the IV World Conservation Congress in 2008, the process began to develop and implement comparable global standards for ecosystems. A working group established by the IUCN has begun formulating a system of quantitative categories and criteria, analogous to those used for species, for assigning levels of threat to ecosystems at local, regional, and global levels. A final system will require definitions of ecosystems; quantification of ecosystem status; identification of the stages of degradation and loss of ecosystems; proxy measures of risk (criteria); classification thresholds for these criteria; and standardized methods for performing assessments. The system will need to reflect the degree and rate of change in an ecosystem's extent, composition, structure, and function, and have its conceptual roots in ecological theory and empirical research. On the basis of these requirements and the hypothesis that ecosystem risk is a function of the risk of its component species, we propose a set of four criteria: recent declines in distribution or ecological function, historical total loss in distribution or ecological function, small distribution combined with decline, or very small distribution. Most work has focused on terrestrial ecosystems, but comparable thresholds and criteria for freshwater and marine ecosystems are also needed. These are the first steps in an international consultation process that will lead to a unified proposal to be presented at the next World Conservation Congress in 2012.Establecimiento de Criterios para la Lista Roja de UICN de Ecosistemas AmenazadosResumenEl potencial para la conservación de muchas especies ha avanzado enormemente porque la Unión Internacional para la Conservación de la Naturaleza (UICN) ha desarrollado criterios objetivos, repetibles y transparentes para evaluar el riesgo de extinción que explícitamente separa la evaluación de riesgo de la definición de prioridades. En el IV Congreso Mundial de Conservación en 2008, el proceso comenzó a desarrollar e implementar estándares globales comparables para ecosistemas. Un grupo de trabajo establecido por la UICN ha formulado un sistema inicial de categorías y criterios cuantitativos, análogos a los utilizados para especies, para asignar niveles de amenaza a ecosistemas a niveles local, regional y global. Un sistema final requerirá de definiciones de ecosistemas; cuantificación del estatus de ecosistemas; identificación de las etapas de degradación y pérdida de los ecosistemas; medidas de riesgo (criterios) alternativas; umbrales de clasificación para esos criterios y métodos estandarizados para la realización de evaluaciones. El sistema deberá reflejar el nivel y tasa de cambio en la extensión, composición, estructura y funcio...

Summary1. Climate change in arctic tundra is projected to increase soil fertility, which may alter plant community composition and ecosystem processes by shifting niche space to favour particular species' life-history strategies. The rate and magnitude of change in soil fertility may be critical to determining plant community responses, and so effects of slow increases in nutrient availability due to climate warming may differ substantially from those of chronic high-level fertilizer additions. 2.We investigated above-and below-ground plant biomass responses to experimental summer warming and above-ground responses to nutrient additions (low-level N and factorial N and P) in a mesic birch hummock tundra community in the central Canadian Low Arctic after eight years of experimental treatment.3. Plant community biomass responses to experimental warming were fundamentally different from those of high-level N and/or P additions, mainly due to opposing effects on the evergreen shrubs. Evergreen shrub above-ground biomass increased 66% with greenhouse warming, but decreased on average 70% with high-level N and/or P additions, driven by the strong responses of Rhododendron subarcticum. Because of this evergreen response, greenhouse-warming increased total above-ground biomass by 32% and total below-ground biomass by 70%, but did not significantly change the total above-ground/below-ground biomass ratio. However, warming increased the shoot/root ratio of Betula glandulosa threefold. 4.Increased soil fertility created interactions between N and P availability, whereby increased P availability led to a substantial increase in inorganic N availability. Meanwhile, the growth of several species that span a range of different functional groups was stimulated by the separate N and P additions. These factorial fertilization results highlight the importance of understanding climate warming impacts on availability of both of these nutrients in order to predict plant community responses.5. Synthesis. Our results strongly suggest that the trajectory of mesic tundra vegetation change with warming depends critically on the rate of increase in soil fertility. The relatively large greenhouse-induced biomass increase in evergreen compared to deciduous shrubs suggests that carbon balance and albedo feedbacks to warming will be restricted in mesic tundra ecosystems, at least in their early responses to climate change.