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Earlier spring phenology observed in many plant species in recent decades provides compelling evidence that species are already responding to the rising global temperatures associated with anthropogenic climate change. There is great variability among species, however, in their phenological sensitivity to temperature. Species that do not phenologically \"track\" climate change may be at a disadvantage if their growth becomes limited by missed interactions with mutualists, or a shorter growing season relative to earlier-active competitors. Here, we set out to test the hypothesis that phenological sensitivity could be used to predict species performance in a warming climate, by synthesizing results across terrestrial warming experiments. We assembled data for 57 species across 24 studies where flowering or vegetative phenology was matched with a measure of species performance. Performance metrics included biomass, percent cover, number of flowers, or individual growth. We found that species that advanced their phenology with warming also increased their performance, whereas those that did not advance tended to decline in performance with warming. This indicates that species that cannot phenologically \"track\" climate may be at increased risk with future climate change, and it suggests that phenological monitoring may provide an important tool for setting future conservation priorities.

Aim The rapidly changing Arctic is ideal for investigating uncertainties in climate projections. Despite the challenges of collecting data in this region, an unprecedented large‐scale survey of shorebirds has been conducted over the last 30 years. Our study aimed to (1) develop probabilistic estimates for the change in suitable habitat for 10 Arctic shorebird species in Canada by 2075 and (2) assess the contribution of modelling decisions to the uncertainty in these estimates. Location Arctic Canada. Methods To evaluate uncertainty, we considered six classes of modelling decisions, yielding 216 unique projections for each species. We tested three decisions that are less commonly explored − the pool of candidate variables, a method for selecting variables, and the maximum distance of tree line dispersal, as well as the modelling algorithm, carbon emissions scenario, and global circulation model. We used a bootstrapping approach, creating a probability distribution for the proportional change in suitable habitat for each species. Results Our findings indicated a substantial risk for 8/10 species to lose over half of their suitable breeding habitat, but this projection is much less certain than has been described previously. While much uncertainty is unexplained, we were surprised that the largest source of uncertainty among our modelling decisions was from our choice of methods for variable selection, that the other modelling decisions were relatively small sources of uncertainty, overshadowing other modelling decisions. Main Conclusions While most scenarios predict a northward shift and significant habitat loss for Arctic‐breeding shorebirds, the Arctic Archipelago of Canada will remain an important refuge because in many other Arctic regions, there is no land farther north for these species to shift into. A comprehensive understanding of uncertainty is important for deciding if future projections can or should be used when planning climate‐resilient protected area networks.

To test whether the occupancy of shorebirds has changed in the eastern Canadian Arctic, and whether these changes could indicate that shorebird distributions are shifting in response to long-term climate change.Location Foxe Basin and Rasmussen Lowlands, Nunavut, Canada.Methods We used a unique set of observations, made 25 years apart, using general linear models to test if there was a relationship between changes in shorebird species' occupancy and their species temperature Index, a simple version of a species climate envelope.Results Changes in occupancy and density varied widely across species, with some increasing and some decreasing. This is despite that overall population trends are known to be negative for all of these species based on surveys during migration. The changes in occupancy that we observed were positively related to the species temperature index, such that the warmer-breeding species appear to be moving into these regions, while colder-breeding species appear to be shifting out of the regions, likely northward.Main Conclusions Our results suggest that we should be concerned about declining breeding habitat availability for bird species whose current breeding ranges are centered on higher and colder latitudes.

AIM: To quantify avian distribution shifts and the extent of niche tracking in response to changing temperature and precipitation patterns. LOCATION: Sweden. METHODS: We used abundance monitoring data to quantify changes in bird species distributions between two time periods, 2000–02 and 2010–12. First we examined shifts at the level of whole distributions using population centroids in temperature, rainfall, altitude, latitude and longitude. We then characterized shifts in temperature and latitude at different parts of species ranges using species response curves (SRC). We accounted for yearly turnover in abundance and sampling effort, and compared the observed shifts with those expected under perfect niche tracking. RESULTS: Most species demonstrated changes in their distributions over the last decade but not all were in response to weather. The degree to which species tracked their climatic niches and the dynamics driving these shifts varied considerably. Only 20% of species shifted in the direction expected given the temperature changes, while few showed a strong response to rainfall. Most shifts did not fully compensate for changes in temperature. Range changes were most evident at the leading edges, but there was some evidence for retractions of trailing edges. Amongst species that tracked temperature, those with southerly distributions were less successful at tracking changes than those in the north. MAIN CONCLUSIONS: Swedish birds demonstrated highly dynamic distributions, with many rapid directional shifts occurring over the last decade. However, only a few species kept pace with observed climatic change. Species that did not track their climatic niche may be tolerant to ongoing climatic change or constrained by strong habitat requirements. We demonstrate that measuring range shifts along both environmental and geographic gradients can help disentangle drivers of distribution changes.

The primary explanation for the latitudinal gradient in species diversity must lie in why species fail to expand ranges across different climatic regimes. Theories of species gradients based in niche conservatism assume that whole clades are confined to particular climatic regimes because the traits they share limit adaptation to alternative regimes. We assess these theories in an analysis of the twofold decline in bird species richness along the Himalayas from the southeast to the northwest. The presence of fewer species in the northwest is entirely due to a steep decline in the number of forest species; species occupying more open habitats show a reversed gradient. Forest species numbers are exceptionally high at midelevations (1,000–2,000 m) in the southeast, which experience a warm, wet climate not present in the northwest, and a high proportion of these species fail to expand their range to the northwest. Despite this, many species do have populations or close relatives that straddle different climatic regimes along altitudinal gradients and/or the regional gradient, implying that climate-based niche conservatism per se does not strongly constrain range limits. We argue that climate- and competition-mediated resource distributions are important in setting northerly range limits and show that one measure of forest resources (foliage density) is lower in the northwest.

• Premise of the study: Predicting species responses to climate change has become a dynamic field in global change research. A crucial question in this debate is whether-or-not species have been and will be able to respond quickly enough to keep up with changing climatic conditions.• Methods: Focusing on fossil pollen records and paleoclimatic simulations, this work assesses the change in realized climatic niches (climatic temporal trajectories) of 20 plant taxa over the last 16000 yr, and whether this tracking has been the same for different climatic niche dimensions.• Key results: Climatic factors showed a consistent trend toward warmer temperatures and higher precipitation. Although the response types varied across taxa, species’ realized climatic niches lagged in response to changes in climatic conditions. Temperature niches responded to late Pleistocene (16000–11000 yr ago) climate change, but did so at slower rates than changes in climatic conditions during the same period. In contrast, precipitation niches were relatively stable from 16000 to 11000 yr ago, but still lagged behind changes in climatic conditions. Changes in temperature and precipitation niches eventually stabilized during the Holocene (11000–1000 yr ago).• Conclusions: These results underscore how the climatic niche realized at any one moment represents a subset of the climate conditions in which a taxon can persist, particularly during times of fast climatic change. Variability in the rates of temporal trajectories across evaluated climatic variables showed taxa specific responses to changes in climatic conditions over time and emphasizes the need to incorporate variation, intensity, and duration of lag effects in assessments of the possible effects of climatic change.

Climate warming allows generalist boreal consumers to expand into Arctic ecosystems. We present experimental and observational field data showing that a generalist boreal insect pest—the winter moth (Operophtera brumata Linnaeus, 1758)—is expanding its outbreak range out of the northern boreal mountain birch forest in northeast Fennoscandia and into the adjacent Low Arctic shrub tundra. This is the first documented example of an outbreaking boreal insect pest expanding into a tundra ecosystem. The expansion has coincided with a long-term advancing trend in the expected hatching date of moth eggs in spring for the study region. We show that the winter moth can complete development on Low Arctic willows and that the density of winter moth larvae in willow thickets is unrelated to the amount of mountain birch (the main host plant in northern boreal forest) in the thickets. However, we also demonstrate that larval densities on willows show a regional-scale spatial decline when moving away from the birch forest and into the shrub tundra. Continued monitoring is needed to establish whether the outbreaks will spread farther into the tundra. The expansion of outbreaking boreal pests into the tundra could alter conventional expectations of increasing vegetation productivity and shrubification in tundra ecosystems. Le réchauffement climatique permet aux consommateurs boréaux généralistes de s’étendre aux écosystèmes arctiques. Les auteurs présentent des données expérimentales et d’observation sur le terrain montrant qu’un insecte nuisible boréal généraliste — l’arpenteuse tardive (Operophtera brumata Linnaeus, 1758) — est en train d’étendre son aire de répartition boréale-nordique hors de la forêt de bouleaux de montagne du nord-est de la Fennoscandie et dans la toundra arbustive aride adjacente du Bas-Arctique. Il s’agit du premier exemple documenté d’un insecte nuisible boréal en pullulation dans un écosystème de toundra. Cette expansion a coïncidé avec une tendance à long terme à l’avancement de la date d’éclosion prévue des œufs d’arpenteuse au printemps dans la région étudiée. Les auteurs montrent que l’arpenteuse tardive peut achever son développement sur les saules du Bas-Arctique et que la densité des larves de l’arpenteuse tardive dans les fourrés de saules n’est pas liée à la quantité de bouleau de montagne (l’hôte principal dans la forêt boréale nordique) dans les fourrés. Cependant, ils démontrent également que les densités de larves sur les saules montrent un déclin spatial à l’échelle régionale lorsque l’on s’éloigne de la forêt de bouleaux et que l’on entre dans la toundra arbustive. Une surveillance continue est nécessaire pour déterminer si les pullulations s’étendront plus loin dans la toundra. L’expansion des ravageurs boréaux dans la toundra pourrait modifier les attentes conventionnelles d’une augmentation de la productivité de la végétation et de l’arbustification dans les écosystèmes de la toundra.

Aim Evidence indicates that species are responding to climate change through distributional range shifts that track suitable climatic conditions. We aim to elucidate the role of meso-scale dispersal barriers in climate-tracking responses. Location South coast of England (the English Channel). Methods Historical distributional data of four intertidal invertebrate species were logistically regressed against sea surface temperature (SST) to determine a climate envelope. This envelope was used to estimate the expected climate-tracking response since 1990 along the coast, which was compared with observed range expansions. A hydrodynamic modelling approach was used to identify dispersal barriers and explore disparities between expected and observed climate tracking. Results Range shifts detected by field survey over the past 20 years were less than those predicted by the changes that have occurred in SST. Hydrodynamic model simulations indicated that physical barriers produced by complex tidal currents have variably restricted dispersal of pelagic larvae amongst the four species. Main conclusions We provide the first evidence that meso-scale hydrodynamic barriers have limited climate-induced range shifts and demonstrate that life history traits affect the ability of species to overcome such barriers. This suggests that current forecasts may be flawed, both by overestimating range shifts and by underestimating climatic tolerances of species. This has implications for our understanding of climate change impacts on global biodiversity.

Southern Ocean ecosystems are under pressure from resource exploitation and climate change1,2. Mitigation requires the identification and protection of Areas of Ecological Significance (AESs), which have so far not been determined at the ocean-basin scale. Here, using assemblage-level tracking of marine predators, we identify AESs for this globally important region and assess current threats and protection levels. Integration of more than 4,000 tracks from 17 bird and mammal species reveals AESs around sub-Antarctic islands in the Atlantic and Indian Oceans and over the Antarctic continental shelf. Fishing pressure is disproportionately concentrated inside AESs, and climate change over the next century is predicted to impose pressure on these areas, particularly around the Antarctic continent. At present, 7.1% of the ocean south of 40°S is under formal protection, including 29% of the total AESs. The establishment and regular revision of networks of protection that encompass AESs are needed to provide long-term mitigation of growing pressures on Southern Ocean ecosystems.

The need to track climate change adaptation progress is being increasingly recognized but our ability to do the tracking is constrained by the complex nature of adaptation and the absence of measurable outcomes or indicators by which to judge if and how adaptation is occurring. We developed a typology of approaches by which climate change adaptation can be tracked globally at a national level. On the one hand, outcome-based approaches directly measure adaptation progress and effectiveness with reference to avoided climate change impacts. However, given that full exposure to climate change impacts will not happen for decades, alternative approaches focus on developing indicators or proxies by which adaptation can be monitored. These include systematic measures of adaptation readiness, processes undertaken to advance adaptation, policies and programs implemented to adapt, and measures of the impacts of these policies and programs on changing vulnerability. While these approaches employ various methods and data sources, and identify different components of adaptation progress to track at the national level, they all seek to characterize the current status of adaptation by which progress over time can be monitored. However, there are significant challenges to operationalizing these approaches, including an absence of systematically collected data on adaptation actions and outcomes, underlying difficulties of defining what constitutes “adaptation”, and a disconnect between the timescale over which adaptation plays out and the practical need for evaluation to inform policy. Given the development of new adaptation funding streams, it is imperative that tools for monitoring progress are developed and validated for identifying trends and gaps in adaptation response.