Reduced variability in range‐edge butterfly populations over three decades of climate warming

Populations at the high latitude edge of species’ geographical ranges are thought to show larger interannual population fluctuations, with subsequent higher local extinction risk, than those within the ‘core’ climatic range. As climate envelopes shift northward under climate warming, however, we would expect populations to show dampened variability. We test this hypothesis using annual abundance indices from 19 butterfly species across 79 British monitoring sites between 1976 and 2009, a period of climatic warming. We found that populations in the latter (warmer) half of the recording period show reduced interannual population variability. Species with more southerly European distributions showed the greatest dampening in population variability over time. Our results suggest that increases in population variability occur towards climatic range boundaries. British sites, previously existing at the margins of suitable climate space, now appear to fall closer to the core climatic range for many butterfly species.     

Birds are tracking climate warming, but not fast enough

Range shifts of many species are now documented as a response to global warming. But whether these observed changes are occurring fast enough remains uncertain and hardly quantifiable. Here, we developed a simple framework to measure change in community composition in response to climate warming. This framework is based on a community temperature index (CTI) that directly reflects, for a given species assemblage, the balance between low- and high-temperature dwelling species. Using data from the French breeding bird survey, we first found a strong increase in CTI over the last two decades revealing that birds are rapidly tracking climate warming. This increase corresponds to a 91 km northward shift in bird community composition, which is much higher than previous estimates based on changes in species range edges. During the same period, temperature increase corresponds to a 273 km northward shift in temperature. Change in community composition was thus insufficient to keep up with temperature increase: birds are lagging approximately 182 km behind climate warming. Our method is applicable to any taxa with large-scale survey data, using either abundance or occurrence data. This approach can be further used to test whether different delays are found across groups or in different land-use contexts.     

Links between plant species’ spatial and temporal responses to a warming climate

To generate realistic projections of species’ responses to climate change, we need to understand the factors that limit their ability to respond. Although climatic niche conservatism, the maintenance of a species’s climatic niche over time, is a critical assumption in niche-based species distribution models, little is known about how universal it is and how it operates. In particular, few studies have tested the role of climatic niche conservatism via phenological changes in explaining the reported wide variance in the extent of range shifts among species. Using historical records of the phenology and spatial distribution of British plants under a warming climate, we revealed that: (i) perennial species, as well as those with weaker or lagged phenological responses to temperature, experienced a greater increase in temperature during flowering (i.e. failed to maintain climatic niche via phenological changes); (ii) species that failed to maintain climatic niche via phenological changes showed greater northward range shifts; and (iii) there was a complementary relationship between the levels of climatic niche conservatism via phenological changes and range shifts. These results indicate that even species with high climatic niche conservatism might not show range shifts as instead they track warming temperatures during flowering by advancing their phenology.     

Incorporating physiology into species distribution models moderates the projected impact of warming on selected Mediterranean marine species

Species distribution models (SDMs) correlate species occurrences with environmental predictors, and can be used to forecast distributions under future climates. SDMs have been criticized for not explicitly including the physiological processes underlying the species response to the environment. Recently, new methods have been suggested to combine SDMs with physiological estimates of performance (physiology-SDMs). In this study, we compare SDM and physiology-SDM predictions for select marine species in the Mediterranean Sea, a region subjected to exceptionally rapid climate change. We focused on six species and created physiology-SDMs that incorporate physiological thermal performance curves from experimental data with species occurrence records. We then contrasted projections of SDMs and physiology-SDMs under future climate (year 2100) for the entire Mediterranean Sea, and particularly the ‘warm’ trailing edge in the Levant region. Across the Mediterranean, we found cross-validation model performance to be similar for regular SDMs and physiology-SDMs. However, we also show that for around half the species the physiology-SDMs substantially outperform regular SDM in the warm Levant. Moreover, for all species the uncertainty associated with the coefficients estimated from the physiology-SDMs were much lower than in the regular SDMs. Under future climate, we find that both SDMs and physiology-SDMs showed similar patterns, with species predicted to shift their distribution north-west in accordance with warming sea temperatures. However, for the physiology-SDMs predicted distributional changes are more moderate than those predicted by regular SDMs. We conclude, that while physiology-SDM predictions generally agree with the regular SDMs, incorporation of the physiological data led to less extreme range shift forecasts. The results suggest that climate-induced range shifts may be less drastic than previously predicted, and thus most species are unlikely to completely disappear with warming climate. Taken together, the findings emphasize that physiological experimental data can provide valuable supplemental information to predict range shifts of marine species.     

Modelling the effect of temperature changes on plant life-form distribution across a treeline ecotone in the tropical Andes

ABSTRACT

Background: Classifying species from the high tropical Andes into plant life forms (PLF) can provide a more functional understanding of tropical treeline dynamics. However, little is known about the potential response of PLFs to climate warming.

Aims: The objective of this work was to evaluate the response of PLFs to environmental conditions above the upper montane forest in the Venezuelan Andes and forecast their potential distribution under warming scenarios using habitat suitability models.

Methods: We classified species into nine PLFs, analysed their current distribution using CCA and non-linear multiple regressions and forecasted their potential distribution under warming scenarios. We used anatomical leaf traits for shrubs and caulescent rosettes to refine their potential responses to climate.

Results: Tree cover sharply decreased with increasing elevation, while shrub and caulescent rosette distribution differed depending on their leaf traits. Projections suggested an upslope shift of all PLFs with warming and an increase in tree cover.

Conclusions: The analysis of the distribution of PLFs, by linking plant adaptive strategies to topography/climate, allowed projecting changes in vegetation physiognomy in response to warming. Projections of a moderate increase in tree cover in the grassland páramo did not indicate the formation of closed forests above the forest line.     

Four decades of plant community change along a continental gradient of warming

Many studies of individual sites have revealed biotic changes consistent with climate warming (e.g., upward elevational distribution shifts), but our understanding of the tremendous variation among studies in the magnitude of such biotic changes is minimal. In this study, we resurveyed forest vegetation plots 40 years after the initial surveys in three protected areas along a west‐to‐east gradient of increasingly steep recent warming trends in eastern Canada (Québec). Consistent with the hypothesis that climate warming has been an important driver of vegetation change, we found an increasing magnitude of changes in species richness and composition from west to east among the three parks. For the two mountainous parks, we found no significant changes in elevational species’ distributions in the easternmost park (raw mean = +11.4 m at Forillon Park) where warming has been minimal, and significant upward distribution shifts in the centrally located park (+38.9 m at Mont‐Mégantic), where the recent warming trend has been marked. Community Temperature Indices (CTI), reflecting the average affinities of locally co‐occurring species to temperature conditions across their geographic ranges (“Species Temperature Indices”), did not change over time as predicted. However, close examination of the underpinnings of CTI values suggested a high sensitivity to uncertainty in individual species’ temperature indices, and so a potentially limited responsiveness to warming. Overall, by testing a priori predictions concerning variation among parks in the direction and magnitude of vegetation changes, we have provided stronger evidence for a link between climate warming and biotic responses than otherwise possible and provided a potential explanation for large variation among studies in warming‐related biotic changes.     

Common garden comparison of the leaf‐out phenology of woody species from different native climates,combined with herbarium records,forecasts long‐term change

A well‐timed phenology is essential for plant growth and reproduction, but species‐specific phenological strategies are still poorly understood. Here, we use a common garden approach to compare biannual leaf‐out data for 495 woody species growing outdoors in Munich, 90% of them not native to that climate regime. For three species, data were augmented by herbarium dates for 140‐year‐long time series. We further meta‐analysed 107 temperate‐zone woody species in which leaf‐out cues have been studied, half of them also monitored here. Southern climate–adapted species flushed significantly later than natives, and photoperiod‐ and chilling‐ sensitive species all flushed late. The herbarium method revealed the extent of species‐specific climate tracking. Our results forecast that: (1) a northward expansion of southern species due to climate warming will increase the number of late flushers in the north, counteracting documented and expected flushing time advances; and (2) photoperiod‐ and chilling‐sensitive woody species cannot rapidly track climate warming.     

The future of cold‐adapted plants in changing climates: Micranthes (Saxifragaceae) as a case study

Research has shown species undergoing range contractions and/or northward and higher elevational movements as a result of changing climates. Here, we evaluate how the distribution of a group of cold‐adapted plant species with similar evolutionary histories changes in response to warming climates. We selected 29 species of Micranthes (Saxifragaceae) representing the mountain and Arctic biomes of the Northern Hemisphere. For this analysis, 24,755 data points were input into ecological niche models to assess both present fundamental niches and predicted future ranges under climate change scenarios. Comparisons were made across the Northern Hemisphere between all cold‐adapted Micranthes, including Arctic species, montane species, and species defined as narrow endemics. Under future climate change models, 72% of the species would occupy smaller geographical areas than at present. This loss of habitat is most pronounced in Arctic species in general, but is also prevalent in species restricted to higher elevations in mountains. Additionally, narrowly endemic species restricted to high elevations were more susceptible to habitat loss than those species found at lower elevations. Using a large dataset and modeling habitat suitability at a global scale, our results empirically model the threats to cold‐adapted species as a result of warming climates. Although Arctic and alpine biomes share many underlying climate similarities, such as cold and short growing seasons, our results confirm that species in these climates have varied responses to climate change and that key abiotic variables differ between these two habitats.     

Climate adaptation is not enough: warming does not facilitate success of southern tundra plant populations in the high Arctic

Rapidly rising temperatures are expected to cause latitudinal and elevational range shifts as species track their optimal climate north and upward. However, a lack of adaptation to environmental conditions other than climate – for example photoperiod, biotic interactions, or edaphic conditions – might limit the success of immigrants in a new location despite hospitable climatic conditions. Here, we present one of the first direct experimental tests of the hypothesis that warmer temperatures at northern latitudes will confer a fitness advantage to southern immigrants relative to native populations. As rates of warming in the Arctic are more than double the global average, understanding the impacts of warming in Arctic ecosystems is especially urgent. We established experimentally warmed and nonwarmed common garden plots at Alexandra Fiord, Ellesmere Island in the Canadian High Arctic with seeds of two forb species (Oxyria digyna and Papaver radicatum) originating from three to five populations at different latitudes across the Arctic. We found that plants from the local populations generally had higher survival and obtained a greater maximum size than foreign individuals, regardless of warming treatment. Phenological traits varied with latitude of the source population, such that southern populations demonstrated substantially delayed leaf‐out and senescence relative to northern populations. Our results suggest that environmental conditions other than temperature may influence the ability of foreign populations and species to establish at more northerly latitudes as the climate warms, potentially leading to lags in northward range shifts for some species.     

Differential sensitivity of planktonic trophic levels to extreme summer temperatures in boreal lakes

The stress–size hypothesis predicts that smaller organisms will be less sensitive to stress. Consequently, climate warming is expected to favour smaller taxa from lower trophic levels and smaller individuals within populations. To test these hypotheses, we surveyed zooplankton communities in 20 boreal lakes in Killarney Provincial Park, Canada during 2005 (an anomalously warm summer) and 2006 (a normal summer). Higher trophic levels had larger responses to warm temperatures supporting the stress–size hypothesis; however, rather than imposing negative effects, higher density and biomass were observed under warmer temperatures. As a result, larger taxa from higher trophic levels were disproportionately favoured with warming, precluding an expected shift towards smaller species. Proportionately greater increases in metabolic rates of larger organisms or altered biotic interactions (e.g. predation and competition) are possible explanations for shifts in biomass distribution. Warmer temperatures also favoured smaller individuals of the two most common species, in agreement with the stress–size hypothesis. Despite this, these populations had higher biomass in the warm summer. Therefore, reduced adult survivorship may have triggered these species to invest in reproduction over growth. Hence, warmer epilimnions, higher zooplankton biomass and smaller individuals within zooplankton populations may function as sensitive indicators of climate warming in boreal lakes.     

Interdecadal changes in at‐sea distribution and abundance of subantarctic seabirds along a latitudinal gradient in the Southern Indian Ocean

Long‐term demographic studies have recently shown that global climate change together with increasing direct impacts of human activities, such as fisheries, are affecting the population dynamics of marine top predators. However, the effects of these factors on species distribution and abundance at sea are still poorly understood, particularly in marine ecosystems of the southern hemisphere. Using a unique long‐term data set of at‐sea observations, we tested for interdecadal (1980s vs. 2000s) changes in summer abundance and distribution of 12 species of Albatrosses and Petrels along a 30° latitudinal gradient between tropical and Antarctic waters of the southern Indian Ocean. There were contrasting effects of climate change on subantarctic seabird distribution and abundance at sea. While subtropical waters showed the highest rate of warming, the species that visited this water mass showed the greatest changes in distribution and abundance. The abundance of Wandering Albatrosses (Diomedea exulans), White‐chinned Petrels (Procellaria aequinoctialis) and Giant Petrels (Macronectes sp.) declined markedly, whereas the other species showed contrasting trends or did not change. With the exception of the White‐chinned Petrel, these decreases were at least partly related to regional increase in sea surface temperature. The southward shift of Wandering Albatross and Prions (Pachyptila spp.) distributions could be ascribed to species redistribution or decrease in abundance due to warming of the subtropical waters. Surprisingly, White‐chinned Petrel distribution shifted northward, suggesting more complex mechanisms. This study is the first to document a shift in species range in the Southern Ocean related to climate change and contrasting abundance changes. It suggests that some species might experience more severe impacts from climate change depending on the water masses they visit. As climate changes are predicted to continue in the next decades, understanding species responses to climate change is crucial for conservation management, especially when their conservation status is critical or unknown.     

Newly arrived or previously overlooked: is there evidence for climate-driven changes in the distribution of molluscs in the Barents Sea?

In recent years, there have been frequent reports of invertebrate species newly recorded from particular areas of the Northeastern Atlantic, and it has often been suggested that these are the result of changes in species ranges due to recent warming. These suggestions make three assumptions: (1) that we have a good knowledge of the fauna of these areas; (2) that new records of “southern” species are more frequent than new records of “northern” species; (3) that climate change is the only factor affecting species range. I tested these assumptions on published records of 30 benthic molluscan species which have been found alive for the first time in the Russian part of the Barents Sea since 2006. Some of the discussed species are warm-water species and may have extended their ranges northward in response to climate change. However, our baseline knowledge of the molluscan fauna of this area before 2006 is limited by the frequent lack of molluscan specialists to study the available material, by the frequent lack of detailed publication and by changes in sampling and processing methods. New records of “southern” species are in fact not significantly commoner than new records of “northern” species. Also reasons other than climate change for observed changes in species distribution should be considered.     

Past and potential future population dynamics of three grouse species using ecological and whole genome coalescent modeling

Studying demographic history of species provides insight into how the past has shaped the current levels of overall biodiversity and genetic composition of species, but also how these species may react to future perturbations. Here we investigated the demographic history of the willow grouse (Lagopus lagopus), rock ptarmigan (Lagopus muta), and black grouse (Tetrao tetrix) through the Late Pleistocene using two complementary methods and whole genome data. Species distribution modeling (SDM) allowed us to estimate the total range size during the Last Interglacial (LIG) and Last Glacial Maximum (LGM) as well as to indicate potential population subdivisions. Pairwise Sequentially Markovian Coalescent (PSMC) allowed us to assess fluctuations in effective population size across the same period. Additionally, we used SDM to forecast the effect of future climate change on the three species over the next 50 years. We found that SDM predicts the largest range size for the cold‐adapted willow grouse and rock ptarmigan during the LGM. PSMC captured intraspecific population dynamics within the last glacial period, such that the willow grouse and rock ptarmigan showed multiple bottlenecks signifying recolonization events following the termination of the LGM. We also see signals of population subdivision during the last glacial period in the black grouse, but more data are needed to strengthen this hypothesis. All three species are likely to experience range contractions under future warming, with the strongest effect on willow grouse and rock ptarmigan due to their limited potential for northward expansion. Overall, by combining these two modeling approaches, we have provided a multifaceted examination of the biogeography of these species and how they have responded to climate change in the past. These results help us understand how cold‐adapted species may respond to future climate changes.     

Different responses of Korean pine (Pinus koraiensis) and Mongolia oak (Quercus mongolica) growth to recent climate warming in northeast China

Different tree species growing in the same area may have different, or even contrasting growth responses to climate change. Korean pine (Pinus koraiensis) and Mongolia oak (Quercus mongolica) are two crucial tree species in temperate forest ecosystems. Six tree-ring chronologies for Korean pine and Mongolia oak were developed by using the zero-signal method to explore their growth response to the recent climate warming in northeast China. Results showed that Mongolia oak radial growth was mainly limited by precipitation in the growing season, while Korean pine growth depended on temperature condition, especially monthly minimum temperature. With the latitude decrease, the relationships between Korean pine growth and monthly precipitation changed from negative to positive correlation, while the positive correlation with monthly temperature gradually weakened. In the contrary, Mongolia oak growth at the three sampling sites was significantly and positively correlated with precipitation in the growing season, while it was negatively correlated with temperature and this relationship decreased with the latitude decrease. The radial growth of Korean pine at different sites showed a clearly discrepant responses to the recent warming since 1980. Korean pine growth in the north site increased with the temperature increase, decreased in the midwest site, and almost unchanged in the southeast site. Conversely, Mongolia oak growth was less affected by the recent climate warming. Our finding suggested that tree species trait and sites are both key factors that affect the response of tree growth to climate change. In addition, the suitable distribution area of Korean pine may be moved northward with the continued global warming in the future, but Mongolia oak may not shift in the same way.     

Biome changes and their inferred climatic drivers in northern and eastern continental Asia at selected times since 40 cal ka <Emphasis Type="SmallCaps">bp</Emphasis>

Recent global warming is pronounced in high-latitude regions (e.g. northern Asia), and will cause the vegetation to change. Future vegetation trends (e.g. the “arctic greening”) will feed back into atmospheric circulation and the global climate system. Understanding the nature and causes of past vegetation changes is important for predicting the composition and distribution of future vegetation communities. Fossil pollen records from 468 sites in northern and eastern Asia were biomised at selected times between 40 cal ka bp and today. Biomes were also simulated using a climate-driven biome model and results from the two approaches compared in order to help understand the mechanisms behind the observed vegetation changes. The consistent biome results inferred by both approaches reveal that long-term and broad-scale vegetation patterns reflect global- to hemispheric-scale climate changes. Forest biomes increase around the beginning of the late deglaciation, become more widespread during the early and middle Holocene, and decrease in the late Holocene in fringe areas of the Asian Summer Monsoon. At the southern and southwestern margins of the taiga, forest increases in the early Holocene and shows notable species succession, which may have been caused by winter warming at ca. 7 cal ka bp. At the northeastern taiga margin (central Yakutia and northeastern Siberia), shrub expansion during the last deglaciation appears to prevent the permafrost from thawing and hinders the northward expansion of evergreen needle-leaved species until ca. 7 cal ka bp. The vegetation-climate disequilibrium during the early Holocene in the taiga-tundra transition zone suggests that projected climate warming will not cause a northward expansion of evergreen needle-leaved species.     

Phenotypic plasticity in the range-margin population of the lycaenid butterfly <Emphasis Type="Italic">Zizeeria maha</Emphasis>

Background  

Many butterfly species have been experiencing the northward range expansion and physiological adaptation, probably due to climate warming. Here, we document an extraordinary field case of a species of lycaenid butterfly, Zizeeria maha, for which plastic phenotypes of wing color-patterns were revealed at the population level in the course of range expansion. Furthermore, we examined whether this outbreak of phenotypic changes was able to be reproduced in a laboratory.     

气候变化下千金榆在我国潜在分布区预测

气候变化严重影响植物的地理分布格局,植物分布对气候变化响应的区域差异性也将为引种和保存提供重要的指导.本研究基于ArcGIS与MaxEnt模型,利用176个千金榆地理信息和13个气候变量,对当前和未来的生态位进行重建.结果表明:模型模拟当代潜在分布区可信度极高,测试集与训练集AUC值分别为0.973和0.957.主要核心适宜区集中在秦岭、长白山及其各自的邻近区域,其他为零星的“岛屿”式分布.贵州、江西、云南、福建等地未发现千金榆的分布,但存在一定的适宜分布区.随着未来气候变暖,千金榆生态适宜区明显增加,主要表现为“向高海拔地区收缩”、“北扩”和“东扩”.但核心适宜区略有减少,具体表现为“南缩”、“中稳”和“北扩”.千金榆的分布对气候变暖的响应存在明显的区域性,在东部江苏、安徽等地,因其独特的地理位置与气候环境,该地区开始成为千金榆生态适宜区;在较低纬度的南方,原有的低海拔地区可能不再适宜千金榆生存;中部秦岭地区气候为南北的渐变区,有较强的缓冲能力,气候变暖对其分布区影响不大;较高纬度的长白山地区及其邻近区域愈发适宜千金榆生存.     

Predicting the impact of climate change on Australia's most endangered snake, Hoplocephalus bungaroides

Aim  To predict how the bioclimatic envelope of the broad-headed snake (BHS) ( Hoplocephalus bungaroides ) may be redistributed under future climate warming scenarios.
Location  South-eastern New South Wales, Australia.
Methods  We used 159 independent locations for the species and 35 climatic variables to model the bioclimatic envelope for the BHS using two modelling approaches – B ioclim and M axent . Predictions were made under current climatic conditions and we also predicted the species distribution under low and high climate change scenarios for 2030 and 2070.
Results  Broad-headed snakes currently encompass their entire bioclimatic envelope. Both modelling approaches predict that suitable climate space for BHS will be lost to varying degrees under both climate warming scenarios, and under the worst case, only 14% of known snake populations may persist.
Main conclusions  Areas of higher elevation within the current range will be most important for persistence of this species because they will remain relatively moist and cool even under climate change and will match the current climate envelope. Conservation efforts should focus on areas where suitable climate space may persist under climate warming scenarios. Long-term monitoring programs should be established both in these areas and where populations are predicted to become extirpated, so that we can accurately determine changes in the distribution of this species throughout its range.     

Differential responses to warming and increased precipitation among three contrasting grasshopper species

We conducted a field manipulation experiment to investigate developmental and demographic responses to warming and increased precipitation in three Inner Mongolian grasshopper species that differ in phenology (an early-season species Dasyhippus barbipes , a mid-season species Oedaleus asiaticus , and a late-season species Chorthippus fallax ). Infrared heaters were used for warming the ground surface by 1–2 °C above the ambient condition and periodic irrigations were applied to simulate a 50% increase in annual precipitation. We found that warming advanced the timing for egg hatching and grasshopper eclosion in each of the three species. However, grasshopper diapause and increased precipitation appeared to offset the effect of warming on egg development. Hatching and development were more strongly affected by warming in the mid-season O. asiaticus and the late-season C. fallax relative to the early-season D. barbipes . Warming by ∼1.5 °C advanced the occurrence of the mid-season O. asiaticus by an average of 4.96 days; while warming and increased precipitation interactively affected the occurrence of the late-season C. fallax , which advanced by 5.53 days. Our data and those of others suggest that most grasshopper species in the Inner Mongolian grassland are likely to extend their distribution northward with climate change. However, because of the differential response to warming we demonstrate for these species, the different grasshopper species are predicted to aggregate toward the middle period of the growing season, potentially increasing interspecific competition and grazing pressure on grasslands.     

Metapopulation shift and survival of woodland birds under climate change: will species be able to track?

Climate change has been widely recognized as a key factor driving changes in species distributions. In this study we use a metapopulation model, with a window of suitable climate moving polewards, to explore population shifts and survival of woodland birds under different climate change scenarios and landscape configurations. Extinction vulnerability and expansion ability are predicted for the middle spotted woodpecker Dendrocopus medius and two alternative r‐K strategies under west European climate change scenarios of 1, 2 and 4°C temperature increase per century, corresponding to isotemperature velocities of ca 2, 4 and 8 km yr^?1. The simulated northward expansion of the bird's distribution is typically in the range of only 0–3 km yr^?1, in spite of 10–20 times larger maximum dispersal distances. This is too slow to track the climate change‐driven range contraction of 4 or 8 km yr^?1 in the south resulting in metapopulation extinction. Especially K‐selected (large‐bodied) species are vulnerable in the simulations. With a temperature increase of 4°C per century bird species go extinct within 104–178 yr. We present a simple approximation formula to predict the mean time to metapopulation extinction using 1) the rate of climate change, which determines the speed of range contraction in the south, 2) the size of the distribution range, which serves as a buffer against extinction, and 3) the northward expansion velocity, determined by species traits and landscape properties. Finally, our results indicate that the northward expansion rate is not constant. It will be initially lagged suggesting that recently observed expansion rates might be underestimations of future northward expansion rates.