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.

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Convergence between species niches and biological traits was investigated for 88 Leucadendron taxa in the Cape Floristic region. First, niche separation analysis was performed to relate species' niche positions/breadths with bioclimatic gradients. These gradients of aridity, seasonality of water availability, heat, and cold stress explained almost all variation in niche distributions. Species present in zones of extreme aridity or temperature exhibited narrower niche breadths than species situated in moderate sites, suggesting that stress-tolerant species do not occupy broad environmental ranges. Second, species niche positions were related to selected biological traits. Species of arid sites had significantly lower blade areas than did species of moist sites, confirming a functional trade-off between stress tolerance and productivity for leaf design. Species dispersal mode was correlated to species niche positions on the aridity gradient, suggesting allometrically determined correlations between leaf design and the design of reproductive structures. Species niche positions were also correlated with flowering traits, with species that initiate flowering in winter found under Mediterranean climate influence and species that initiate flowering in spring in sites with greater summer rainfall input. By interrelating species niche positions on bioclimatic gradients with selected biological traits, we explored a novel biogeographical approach to understanding species distributions.

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A key feature of life’s diversity is that some species are common but many more are rare. Nonetheless, at global scales, we do not know what fraction of biodiversity consists of rare species. Here, we present the largest compilation of global plant diversity to quantify the fraction of Earth’s plant biodiversity that are rare. A large fraction, ~36.5% of Earth’s ~435,000 plant species, are exceedingly rare. Sampling biases and prominent models, such as neutral theory and the k-niche model, cannot account for the observed prevalence of rarity. Our results indicate that (i) climatically more stable regions have harbored rare species and hence a large fraction of Earth’s plant species via reduced extinction risk but that (ii) climate change and human land use are now disproportionately impacting rare species. Estimates of global species abundance distributions have important implications for risk assessments and conservation planning in this era of rapid global change.

Extensive tree planting is widely promoted for reducing atmospheric CO 2. In Africa, 1 million km 2 , mostly of grassy biomes, has been targeted for 'restoration' by 2030. The target is based on the erroneous assumption that these biomes are deforested and degraded. We discuss the pros and cons of exporting fossil fuel emission problems to Africa. Main text Africa is the grassiest continent. The grasses support Africa's great natural asset, the remaining herds of the Pleistocene megafauna (Figure1). Africa's grassy biomes are rich in forest-averse birds, reptiles, plants, and insects. They were the cradle of our hominid ancestors and today are home to over 300 million people. But these open grassy landscapes could be transformed if trees-for-carbon projects inappropriately target them, for example, by 'restoring forest landscapes' over 1 million km 2 by 2020 and 3.5 million km 2 by 2030

egetation dynamics involves processes operating at widely different spatial and temporal scales, from stomatal opening and closing (minutes to days, at the leaf level) to biome shifts (decades to centuries, across entire continents). Tremendous research efforts have been devoted to understanding and predicting how plant processes and functional traits of individuals combine to determine the structure, function and dynamics of vegetation on larger scales. To integrate process understanding from different disciplines, dynamic vegetation models (DVMs) have been developed that combine elements from plant biogeography, biogeochemistry, plant physiology, forest ecology and micrometeorology. The best-known DVMs, dynamic global vegetation models (DGVMs), have found a wide field of application, including assessments of land-atmosphere carbon, water and trace gas exchanges; water resources; impacts of environmental change on plants and ecosystems; land management; and feedbacks from vegetation changes to regional and global climates 1,2. DVMs have also been applied on local scales for testing of ecological hypotheses and to answer practical questions in forest management and agriculture. All DVMs are based on the assumption of universally valid processes, which, in principle, enable them to make predictions under conditions outside the range of observations used for model development.

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