She is aConservation Scientist specialized in macroecology and biogeography, and is currently working to quantitate vegetation shifts under climatic change in extreme biomes such as the tundra and the savannah.

Vegetation composition shifts, and in particular, shrub expansion across the Arctic tundra are some of the most important and widely observed responses of high-latitude ecosystems to rapid climate warming. These changes in vegetation potentially alter ecosystem carbon balances by affecting a complex set of soil–plant–atmosphere interactions. In this review, we synthesize the literature on (a) observed shrub expansion, (b) key climatic and environmental controls and mechanisms that affect shrub expansion, (c) impacts of shrub expansion on ecosystem carbon balance, and (d) research gaps and future directions to improve process representations in land models. A broad range of evidence, including in-situ observations, warming experiments, and remotely sensed vegetation indices have shown increases in growth and abundance of woody plants, particularly tall deciduous shrubs, and advancing shrublines across the circumpolar Arctic. This recent shrub expansion is affected by several interacting factors including climate warming, accelerated nutrient cycling, changing disturbance regimes, and local variation in topography and hydrology. Under warmer conditions, tall deciduous shrubs can be more competitive than other plant functional types in tundra ecosystems because of their taller maximum canopy heights and often dense canopy structure. Competitive abilities of tall deciduous shrubs vs herbaceous plants are also controlled by variation in traits that affect carbon and nutrient investments and retention strategies in leaves, stems, and roots. Overall, shrub expansion may affect tundra carbon balances by enhancing ecosystem carbon uptake and altering ecosystem respiration, and through complex feedback mechanisms that affect snowpack dynamics, permafrost degradation, surface energy balance, and litter inputs. Observed and projected tall deciduous shrub expansion and the subsequent effects on surface energy and carbon balances may alter feedbacks to the climate system. Land models, including those integrated in Earth System Models, need to account for differences in plant traits that control competitive interactions to accurately predict decadal- to centennial-scale tundra vegetation and carbon dynamics.

Aim Biomes worldwide are shifting with global change. Biomes whose extents are limited by temperature or precipitation, such as the tundra and savanna, may be particularly strongly affected by climate change. While woody plant encroachment is prevalent across both biomes, its relationship to temperature and precipitation change remains unknown. Here, we quantify the degree to which woody encroachment is related to climate change and identify its main associated drivers. Location Tundra and savanna biomes. Time period 1992 ± 20.27–2010 ± 5.62 (mean ± SD). 1876–2016 (range). Major taxa studied Woody plants (shrubs and trees). Methods We compiled a dataset comprising 1,089 records from 899 sites of woody plant cover over time and attributed drivers of woody cover change across these two biomes. We calculated cover change in each biome and assessed the degree to which cover change corresponds to concurrent temperature and precipitation changes using multiple climate metrics. Finally, we conducted a quantitative literature review of the relative importance of attributed drivers of woody cover change. Results Woody encroachment was widespread geographically and across climate gradients. Rates of woody cover change (positive or negative) were 1.8 times lower in the tundra than in the savanna (1.8 vs. 3.2%), while rates of woody cover increase (i.e., encroachment) were c. 1.7 times lower in the tundra compared with the savanna (3.7 vs. 6.3% per decade). In the tundra, magnitudes of woody cover change did not correspond to climate, while in the savanna, greater cover change corresponded with increases in precipitation. We found higher rates of woody cover change in wetter versus drier sites with warming in the tundra biome, and higher rates of woody cover change in drier versus wetter sites with increasing precipitation in the savanna. However, faster rates of woody cover change were not associated with more rapid rates of climate change across sites, except for maximum precipitation in the savanna. Main conclusions Woody encroachment was positively related to warming in the tundra and increased rainfall in the savanna. However, cover change rates were not predicted by rates of climate change, which can be partially explained by climate interactions in both biomes. Additional likely influences include site‐level factors, time‐lags, plant‐specific responses, and land use and other non‐climate drivers. Our findings highlight the complex nature of climate change impacts in biomes limited by seasonality, which should be accounted for to realistically estimate future responses across open biomes under global change scenarios.

Europe has a long tradition of exploiting marine fishes and is promoting marine economic activity through its Blue Growth strategy. This increase in anthropogenic pressure, along with climate change, threatens the biodiversity of fishes and food security. Here, we examine the conservation status of 1,020 species of European marine fishes and identify factors that contribute to their extinction risk. Large fish species (greater than 1.5 m total length) are most at risk; half of these are threatened with extinction, predominantly sharks, rays and sturgeons. This analysis was based on the latest International Union for Conservation of Nature (IUCN) European regional Red List of marine fishes, which was coherent with assessments of the status of fish stocks carried out independently by fisheries management agencies: no species classified by IUCN as threatened were considered sustainable by these agencies. A remarkable geographic divergence in stock status was also evident: in northern Europe, most stocks were not overfished, whereas in the Mediterranean Sea, almost all stocks were overfished. As Europe proceeds with its sustainable Blue Growth agenda, two main issues stand out as needing priority actions in relation to its marine fishes: the conservation of marine fish megafauna and the sustainability of Mediterranean fish stocks.arine fishes exhibit high biodiversity 1,2 and have been culturally and nutritionally important throughout human history 3 . Europe, in particular, has a well-documented history of exploiting marine fish populations, written records of which commence in the classical works of ancient Greece. Although this historical exploitation has undoubtedly altered populations 4,5 and changed many seascapes 6 , marine defaunation in the region has not been as great as in terrestrial systems 7 . However, the use of ocean space and resources is increasing due to Europe's Blue Growth strategy 8 , the nutritional requirements of an expanding human population are growing 9,10 and marine ecosystems will experience unusually rapid changes in future due to climate change 11,12 . Consequently there are imminent threats both to European marine biodiversity and fish resources 13 . It is important, therefore, to assess the threats of extinction to fish species and to ensure consistency in the management approach by the various agencies involved.We analysed data on the conservation status of 1,020 species of Europe's marine fishes from the recent International Union for Conservation of Nature (IUCN) Red List assessments 14 to identify characteristics that make Europe's fishes most susceptible to extinction risk. We then compared the Red List with 115 fish stock assessments (of 31 species) made by intergovernmental agencies charged with providing advice on the exploitation of commercial fishes. Previous comparisons of this sort applied criteria under various modelling assumptions [15][16][17] or limited the comparison to biomass reference points 18 . ResultsOf the 1,020 European marine fish species that were asses...

© 2 0 1 7 M a c m i l l a n P u b l i s h e r s L i m i t e d , p a r t o f S p r i n g e r N a t u r e . A l l r i g h t s r e s e r v e d .

Hottentot Fern (Thelypteris pozoi) is a widespread species, although in Europe it is only found in the Macaronesian islands, Spain and France, where it is usually found near the sea. It has been assessed as Least Concern.

Climate change is leading to species redistributions. In the tundra biome, shrubs are generally expanding, but not all tundra shrub species will benefit from warming. Winner and loser species, and the characteristics that may determine success or failure, have not yet been fully identified. Here, we investigate whether past abundance changes, current range sizes and projected range shifts derived from species distribution models are related to plant trait values and intraspecific trait variation. We combined 17,921 trait records with observed past and modelled future distributions from 62 tundra shrub species across three continents. We found that species with greater variation in seed mass and specific leaf area had larger projected range shifts, and projected winner species had greater seed mass values. However, trait values and variation were not consistently related to current and projected ranges, nor to past abundance change. Overall, our findings indicate that abundance change and range shifts will not lead to directional modifications in shrub trait composition, since winner and loser species share relatively similar trait spaces.

Climate change is leading to a species redistributions. In the tundra biome, many shrub species are expanding into new areas, a process known as shrubification. However, not all tundra shrub species will benefit from warming. Winner and loser species (those projected to expand and contract their ranges, and/or those that have increased or decreased in cover over time), and the characteristics that may determine success or failure, have not been fully identified. Here, we investigate whether current range sizes are related to plant trait values and intraspecific trait variation by combining 17,921 trait records and distribution data from 62 shrub species across three continents (>30 degrees north). In addition, we determine which traits are associated with species projected by species distribution models to expand or contract their ranges under climate change, and species that have undergone past cover changes over time. Winner and loser shrub species identified from projected range shifts generally differed from those identified from observed past cover change. We found that greater variation in seed mass and specific leaf area were related to larger projected range shifts. Projected winner species generally had greater seed mass values than ‘no change’ and loser species. However, contrary to our expectations, traits’ values and variation were not consistently related to current and projected ranges, and depended upon the future climate scenarios considered in range projections. There were no clear relationships either between cover change over time and trait values or variation. Overall, our findings indicate that abundance changes and projected range shifts will not lead to directional modifications in shrub trait composition or variation with future warming, since winner and loser species share relatively similar trait spaces based on commonly measured traits. Future research could investigate other morpho-physiological traits underpinning climatic preferences, which might better predict future range and abundance changes.