Latitudinal Range Shifts Research Articles

Marine invertebrate migrations trace climate change over 450 million years

AbstractAimPoleward migration is a clear response of marine organisms to current global warming but the generality and geographical uniformity of this response are unclear. Marine fossils are expected to record the range shift responses of taxa and ecosystems to past climate change. However, unequal sampling (natural and human) in time and space biases the fossil record, restricting previous studies of ancient migrations to individual taxa and events. We expect that temporal changes in the latitudinal distribution of surviving taxa will reveal range shifts to trace global climate change.LocationGlobal.Time periodPost‐Cambrian Phanerozoic aeon.Major taxa studiedWell‐fossilized marine benthic invertebrates comprising stony corals, bivalves, gastropods, brachiopods, trilobites and calcifying sponges.MethodsWe track deviations in the latitudinal distribution of range centres of age boundary crossing taxa from the expected distribution, and compare responses across latitudes. We build deviation time series, spanning hundreds of million years, from fossil occurrences and test correlations with seawater temperature estimates derived from stable oxygen isotopes of fossils.ResultsSeawater temperature and latitudinal deviations from sampling are positively correlated over the post‐Cambrian Phanerozoic. Simulations suggest that sampling patterns are highly unlikely to drive this putative signal of range shifts. Systematically accounting for known sampling issues strengthens this correlation, so that climate is capable of explaining nearly a third of the variance in ancient latitudinal range shifts. The relationship is stronger in low latitude taxa than higher latitude taxa, and in warm ages than cool ages.Main conclusionsLatitudinal range shifts occurred in concert with climate change throughout the post‐Cambrian Phanerozoic. Low latitude taxa show the clearest climate‐migration signal through time, corroborating predictions of their shift in a warming future.

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.

Can changes in ant diversity along elevational gradients in tropical and subtropical Australian rainforests be used to detect a signal of past lowland biotic attrition?

Increasing temperatures are predicted to have profound effects on montane ecosystems. In tropical forests, biotic attrition may reduce lowland diversity if losses of species due to upslope range shifts are not matched by influxes of warmer-adapted species, either because there are none or their dispersal is impeded. Australian rainforests consist of a north-south chain of patches, broken by dry corridors that are barriers to the dispersal of rainforest species. These rainforests have repeatedly contracted and expanded during Quaternary glacial cycles. Many lowland rainforests are expansions since the Last Glacial Maximum and may, therefore, show a signal of historical biotic attrition. We surveyed ants from replicated sites along three rainforest elevational transects in eastern Australia spanning 200 to 1200m a.s.l. and nearly 14 degrees of latitude. We examined elevational patterns of ant diversity and if there was possible evidence of lowland biotic attrition. Each transect was in a different biogeographic region; the Australian Wet Tropics (16.3 degrees S), the central Queensland coast (21.1 degrees S) and subtropical south-eastern Queensland (28.1 degrees S). We calculated ant species density (mean species per site) and species richness (estimated number of species by incorporating site-to-site species turnover) within elevational bands. Ant species density showed no signal of lowland attrition and was high at low and mid-elevations and declined only at high elevations at all transects. Similarly, estimated species richness showed no evidence of lowland attrition in the Wet Tropics and subtropical south-east Queensland; species richness peaked at low elevations and declined monotonically with increasing elevation. Persistence of lowland rainforest refugia in the Wet Tropics during the Last Glacial Maximum and latitudinal range shifts of ants in subtropical rainforests during the Holocene climatic optimum may have counteracted lowland biotic attrition. In central Queensland, however, estimated richness was similar in the lowlands and mid-elevations, and few ant species were indicative of lower elevations. This may reflect historical biotic attrition due perhaps to a lack of lowland glacial refugia and the isolation of this region by a dry forest barrier to the north.

Deep reefs are climatic refugia for genetic diversity of marine forests

AbstractAimPast climate‐driven range shifts shaped intraspecific diversities of species world‐wide. Earlier studies, focused on glacial refugia, might have overlooked genetic erosion at lower latitudes associated with warmer periods. For marine species able to colonize deeper waters, depth shifts might be important for local persistence, preventing some latitudinal shifts, analogous to elevational refugia in terrestrial habitats. In this study, we asked whether past latitudinal or depth range shifts explain extant gene pools in Saccorhiza polyschides, a large habitat structuring brown alga distributed from coastal to offshore deep reefs.LocationNorth‐east Atlantic and western Mediterranean basin.MethodsGenetic structure and diversity were inferred using seven microsatellite loci, for 27 sites throughout the entire distributional range. Ecological niche modelling (ENM) was performed with and without information about genetic structure (sub‐taxon niche structure) to predict distributions for the Last Glacial Maximum (LGM), the warmer Mid‐Holocene (MH) and the present.ResultsBoth ENM approaches predicted a wider potential distribution in deeper waters than is presently known, a post‐glacial expansion to northern shores and the extirpation of southern edges during the warmer MH. Genetic data corroborated range dynamics, revealing three major genetic groups with current boundaries in the Bay of Biscay and the Lisbon coastal region, pinpointing ancient refugial origins. Despite extensive southern range contraction, the southernmost warmer regions are still the richest in genetic diversity, indicating long‐term persistence of large populations. ENMs suggested that this could only have been possible due to stable refugia in deeper reefs.Main conclusionsThe global distribution of gene pools of temperate marine forests is explained by past range shifts that structured both latitudinal glacial refugia and depth refugia during warmer periods. Deep rear edge populations play a fundamental role during periods of extreme climate, allowing persistence and retaining some of the largest genetic diversity pools of the species' distribution.

Cold temperature extremes during spring do not limit the range shift of Mediterranean pines into regions with intermittent frost

Summary Bioclimatic envelope models have predicted latitudinal range shifts of tree species in Europe following climate change. Accordingly, Mediterranean species will be able to migrate northwards if climatic conditions become warmer and dryer. Frost, on the other hand, is an important and recurring factor in temperate and boreal regions causing damage to buds and leaves, and potentially limiting the survival of Mediterranean tree species or populations at higher latitudes. Since species distribution models rely on average climatic parameters, they may underestimate the risk of frost damage from low temperature extremes. We measured the cold hardiness of Pinus sylvestris, Pinus nigra and Pinus halepensis seedlings from a total of 11 European populations growing in a common garden in a cold Central Alpine valley on seven dates between February and July 2013. On each date, needles were artificially frozen at several temperatures and the temperature estimated at which 50% of the needle tissue is damaged (LT50; relative electrolyte leakage). Cold hardiness did not differ between populations of the same species and was not related to the minimum temperatures at the seed origin. In comparison with deciduous trees, Mediterranean P. sylvestris and P. nigra maintained extremely wide safety margins against frost throughout late winter and spring. By contrast, safety margins of P. halepensis were much narrower until March and winter cold hardiness was in the range of regularly recurring low temperature events in Central Europe. According to the measured LT50 values, the migration of a wide range of drought‐tolerant populations of P. sylvestris and P. nigra from the Mediterranean to Central and Western Europe is not limited by intermittent cold temperature extremes in spring. They are notably as well adapted to frost as populations from Central Alpine origin. Differences in dehardening patterns between species demonstrate the importance of analysing cold hardiness repeatedly during potentially sensitive periods in order to predict species range shifts in the context of climatic change.

Models for adaptive forest management

Anthropogenic climate change has been shown to impact forests around the globe (IPCC 2014). Given the expected future climate change as summarized in the Fifth Assessment Report of the IPCC (IPCC 2013), the associated impacts are likely to strongly affect forest resilience as well as the products and services that forests provide to human societies (Reyer et al. 2015). In Europe, the extreme drought in the year 2003 (Ciais et al. 2005), a series of devastating storms (Central Europe 1990, France and Switzerland 1999, Slovakia 2004, Sweden 2005, Central Europe 2007) and severe fire seasons (Portugal 2003, Greece 2007) are clear signals. Not only trees are affected, but shifts in the altitudinal zones affected by bark beetle damages are observed as well (Krehan and Steyrer 2005). Also, latitudinal range shifts of biotic disturbance agents (Battisti et al. 2005) are early warning signals of future changes that may be considerably more severe (Lindner et al. 2010; Nabuurs et al. 2013). Since European forests are intensively managed, adaptations of current management practices may hold promise in a changing climate. However, this is a key challenge for sustainable resource management in Europe and also worldwide, as forest managers must deal with novel phenomena and multiple trade-offs. Not only climate is changing, but also societal demands for goods and services from forests. For example, the recent renewable energy strategy of the European Union is expected to result in a much greater demand for biomass for bio-energy generation. This intensifies competition for resources between forest industry, the energy sector and nature conservation/other protective functions and services (including biodiversity, protection from natural hazards, landscape aesthetics, recreation and tourism). Thus, management decisions are increasing in complexity to reflect not only the changing societal needs, but also the changing environmental conditions. The project MOdels for adapTIVE forest management (MOTIVE) has evaluated the consequences of this intensified competition for forest resources given climate and land-use change. The project focused on a wide range of European forest types under different intensities of forest management. MOTIVE aimed at developing and evaluating strategies that can adapt forest management practices to balance multiple objectives under changing environmental conditions. A special focus was put on forest models that can be used as tools to reflect different forest management strategies under changing climatic conditions. European forests and the strategies to manage them are diverse, with each region featuring different tree species, & Christopher Paul Oliver Reyer christopher.reyer@pik-potsdam.de; reyer@pik-potsdam.de

Latitudinal range shifts of tree species in the United States across multi-decadal time scales

It is expected that some species will shift poleward in range due to climate change. However, despite numerous publications that project species distributions under climate change scenarios, there is less evidence for current latitudinal shifts by tree species, in part because ranges are dynamic and complex to measure. We developed a method to compare tree ranges using continental USDA Forest Service Forest Inventory and Analysis tree surveys during an interval of approximately 28 years. We analyzed compositional differences in ecological subsections within latitudinal bands using repeated measures ANOVA and considered differences in bands at the outer northern and southern range edges combined with increased area to indicate range expansion. Out of a pool of 74 relatively common species, we detected 12 species that had significant increases and expansion in the northern outer band, 13 species that had significant increases and expansion in the southern outer band, and one species that increased and expanded in both northern and southern bands. However, seven species with significant increases in the northern outer band in the contiguous United States had distributions that extended within Canada so that shifts do not represent increases in the northernmost latitudinal band for these species. Uniform poleward migration was not detectable and the number of species shifting southward suggests influence of other driving factors than climate change, including assisted migration of tree species through landscaping and a cascade of range shifts along ecotonal boundaries due to fire exclusion and land use.

Molecular phylogeography and ecological niche modelling of a widespread herbaceous climber, Tetrastigma hemsleyanum (Vitaceae): insights into Plio-Pleistocene range dynamics of evergreen forest in subtropical China.

Warm-temperate evergreen (WTE) forest represents the typical vegetation type of subtropical China, but how its component species responded to past environmental change remains largely unknown. Here, we reconstruct the evolutionary history of Tetrastigma hemsleyanum, an herbaceous climber restricted to the WTE forest. Twenty populations were genotyped using chloroplast DNA sequences and nuclear microsatellite loci to assess population structure and diversity, supplemented by phylogenetic dating, ancestral area reconstructions and ecological niche modeling (ENM) of the species distributions during the Last Glacial Maximum (LGM) and at present. Lineages in Southwest vs Central-South-East China diverged through climate/tectonic-induced vicariance of an ancestral southern range during the early Pliocene. Long-term stability in the Southwest contrasts with latitudinal range shifts in the Central-South-East region during the early-to-mid-Pleistocene. Genetic and ENM data strongly suggest refugial persistence in situ at the LGM. Pre-Quaternary environmental changes appear to have had a persistent influence on the population genetic structure of this subtropical WTE forest species. Our findings suggest relative demographic stability of this biome in China over the last glacial-interglacial cycle, in contrast with palaeobiome reconstructions showing that this forest biome retreated to areas of today's tropical South China during the LGM.

Acute combined pressure and temperature exposures on a shallow-water crustacean: Novel insights into the stress response and high pressure neurological syndrome

Little is known about the ecological and physiological processes governing depth distribution limits in species. Temperature and hydrostatic pressure are considered to be two dominant factors. Research has shown that some marine ectotherms are shifting their bathymetric distributions in response to rapid anthropogenic ocean surface warming. Shallow-water species unable to undergo latitudinal range shifts may depend on bathymetric range shifts to seek refuge from warming surface waters. As a first step in constraining the molecular basis of pressure tolerance in shallow water crustaceans, we examined differential gene expression in response to acute pressure and temperature exposures in juveniles of the shallow-water shrimp Palaemonetes varians. Significant increases in the transcription of genes coding for an NMDA receptor-regulated protein, an ADP ribosylation factor, β-actin, two heat shock protein 70kDa isoforms (HSP70), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were found in response to elevated pressure. NMDA receptors have been implicated in pathways of excitotoxic damage to neurons and the onset of high pressure neurological syndrome (HPNS) in mammals. These data indicate that the sub-lethal effects of acute barotrauma are associated with transcriptional disturbances within the nervous tissue of crustaceans, and cellular macromolecular damage. Such transcriptional changes lead to the onset of symptoms similar to that described as HPNS in mammals, and may act as a limit to shallow water organisms' prolonged survival at depth.

Asymmetric changes of growth and reproductive investment herald altitudinal and latitudinal range shifts of two woody species.

Ongoing changes in global climate are altering ecological conditions for many species. The consequences of such changes are typically most evident at the edge of the geographical distribution of a species, where range expansions or contractions may occur. Current demographical status at geographical range limits can help us to predict population trends and their implications for the future distribution of the species. Thus, understanding the comparability of demographical patterns occurring along both altitudinal and latitudinal gradients would be highly informative. In this study, we analyse the differences in the demography of two woody species through altitudinal gradients at their southernmost distribution limit and the consistency of demographical patterns at the treeline across a latitudinal gradient covering the complete distribution range. We focus on Pinus sylvestris and Juniperus communis, assessing their demographical structure (density, age and mortality rate), growth, reproduction investment and damage from herbivory on 53 populations covering the upper, central and lower altitudes as well as the treeline at central latitude and northernmost and southernmost latitudinal distribution limits. For both species, populations at the lowermost altitude presented older age structure, higher mortality, decreased growth and lower reproduction when compared to the upper limit, indicating higher fitness at the treeline. This trend at the treeline was generally maintained through the latitudinal gradient, but with a decreased growth at the northern edge for both species and lower reproduction for P. sylvestris. However, altitudinal and latitudinal transects are not directly comparable as factors other than climate, including herbivore pressure or human management, must be taken into account if we are to understand how to infer latitudinal processes from altitudinal data.

The effects of changing climate on faunal depth distributions determine winners and losers.

Changing climate is predicted to impact all depths of the global oceans, yet projections of range shifts in marine faunal distributions in response to changing climate seldom evaluate potential shifts in depth distribution. Marine ectotherms' thermal tolerance is limited by their ability to maintain aerobic metabolism (oxygen- and capacity-limited tolerance), and is functionally associated with their hypoxia tolerance. Shallow-water (<200 m depth) marine invertebrates and fishes demonstrate limited tolerance of increasing hydrostatic pressure (pressure exerted by the overlying mass of water), and hyperbaric (increased pressure) tolerance is proposed to depend on the ability to maintain aerobic metabolism, too. Here, we report significant correlation between the hypoxia thresholds and the hyperbaric thresholds of taxonomic groups of shallow-water fauna, suggesting that pressure tolerance is indeed oxygen limited. Consequently, it appears that the combined effects of temperature, pressure and oxygen concentration constrain the fundamental ecological niches (FENs) of marine invertebrates and fishes. Including depth in a conceptual model of oxygen- and capacity-limited FENs' responses to ocean warming and deoxygenation confirms previous predictions made based solely on consideration of the latitudinal effects of ocean warming (e.g. Cheung et al., 2009), that polar taxa are most vulnerable to the effects of climate change, with Arctic fauna experiencing the greatest FEN contraction. In contrast, the inclusion of depth in the conceptual model reveals for the first time that temperate fauna as well as tropical fauna may experience substantial FEN expansion with ocean warming and deoxygenation, rather than FEN maintenance or contraction suggested by solely considering latitudinal range shifts.

Species distribution models and mitochondrial DNA phylogeography suggest an extensive biogeographical shift in the high‐intertidal seaweed Pelvetia canaliculata

AbstractAimSpecies distributions have been continuously adjusting to changing climatic conditions throughout the glacial–interglacial cycles. In the marine realm, evidence suggests that latitudinal range shifts, involving both spatial expansions and trailing‐edge contractions, may represent a common response to climatic oscillations. The biogeographical histories of coastal organisms, however, have been inferred primarily using molecular markers, potentially overlooking past range dynamics beyond contemporary rear edges. In this study we combined species distribution models (SDMs) and mitochondrial DNA (mtDNA) data to investigate the biogeographical history of the high‐intertidal seaweed Pelvetia canaliculata. We investigated the hypotheses that its distribution is set by both marine and terrestrial climates and that its range has shifted northwards since the Last Glacial Maximum.LocationNorth‐eastern Atlantic intertidal from Portugal to Norway.MethodsIn total, 432 individuals at 27 sites covering the extant range of Pelvetia canaliculata were sampled and sequenced for a c. 500 bp mtDNA intergenic spacer. A niche model was developed using marine and terrestrial variables. Range dynamics were reconstructed based on the geographical patterns of genetic variation and on the SDM projections for the Last Glacial Maximum (LGM) and the present.ResultsThe best distribution models incorporated both marine and terrestrial variables. LGM projections revealed suitable habitat between southern Morocco and the periglacial shorelines of the Celtic Sea. Pelvetia canaliculata exhibited a highly structured phylogeography, being subdivided into three largely disjunct lineages, two of them endemic to Iberia. The central/northern European lineage exhibited the highest haplotypic diversity and showed a consistent decline in nucleotide diversity and haplotypic richness at higher latitudes.Main conclusionsAssuming species/climate equilibrium, SDMs supported the hypothesis of a post‐glacial latitudinal range shift. Molecular variation revealed contrasting demographic behaviours in Iberian and periglacial regions. In Iberia the low haplotypic diversity suggested complex range dynamics that are not fully captured by SDM projections. Periglacial regions, identified as the source of poleward colonization, were inferred to have been comparatively more stable. Greater attention should be paid to marine range dynamics at low‐latitude range margins, particularly in genetically structured low‐dispersal species exhibiting southern endemic variation.

New Distributional Data of Butterflies in the Middle of the Mediterranean Basin: An Area Very Sensitive to Expected Climate Change

Butterflies are known to be very sensitive to environmental changes. Species distribution is modified by climate warming with latitudinal and altitudinal range shifts, but also environmental perturbations modify abundance and species composition of communities. Changes can be detected and described when large datasets are available, but unfortunately only for few Mediterranean countries they were created. The butterfly fauna of the Mediterranean Basin is very sensitive to climate warming and there is an urgent need of large datasets to investigate and mitigate risks such as local extinctions or new pest outbreaks. The fauna of Calabria, the southernmost region of peninsular Italy, is composed also of European species having here their southern range. The aim of this dataset paper is to increase and update the knowledge of butterfly distribution in a region very sensitive to climate warming that can become an early‐warning area.

Complex habitat changes along elevational gradients interact with resource requirements of insect specialist herbivores

Stenothermal habitat specialists such as monophagous insects may be threatened by climate-change induced range shifts, if resource requirements along migration routes or future habitats are not met. Little is known about altitudinal shifts of inconspicuous, less mobile species relative to latitudinal range shifts in prominent, mobile organisms such as butterflies. Here, we address three questions: What are the resource requirements—habitat area, quality and fragmentation—for two specialist herbivores? How do habitat characteristics change with altitude? Do species resource requirements suggest an increased vulnerability towards temporal or spatial bottlenecks under climate change? We mapped the spatial distribution of a riparian shrub, Veronica stricta (Plantaginaceae), at local (300 m elevational gradient, n = 252 patches) and regional scales (600 m gradient; n = 102) in the Tongariro National Park, New Zealand. Patch occupancy and patch-level population dynamics of Trioza obscura (Hemiptera: Triozidae) and an undescribed gall midge (Diptera: Cecidomyiidae) were recorded in 2010 and 2011. Habitat suitability and population dynamics were predicted with generalized linear models, applying information theoretic model averaging. Habitat area had the largest positive influence on insect presence and survivorship, the latter benefitting from larger insect populations. Habitat quality showed a species-dependent effect on occurrence (T. obscura: negative effect of plant shade; cecidomyiid: positive effect of host inflorescences) and survival (T. obscura: positive response to leaf-nitrogen and host size; cecidomyiid: positive response to inflorescence abundance). Only cecidomyiid colonization had a weak negative response to habitat fragmentation. Altitude contributed positively to patch suitability and survivorship of the cecidomyiid, but decreased survivorship of T. obscura. Altitude-related changes in the landscape matrix, such as the transition from forested to subalpine vegetation, positively affected habitat area and fragmentation, which in turn offset a steady decrease in host plant size (i.e., patch quality). Our study revealed that habitat area, quality and fragmentation do not always follow simple linear trends along elevational gradients. We recommend that species distribution models should consider these complex patterns when predicting range shifts. We suggest that species vulnerability to climate change depends on whether resource requirements allow for upward migration and suitable habitats are available in future distribution ranges.

REGIONAL-SCALE MARINE FAUNAL CHANGE IN EASTERN AUSTRALIA DURING PERMIAN CLIMATE FLUCTUATIONS AND ITS RELATIONSHIP TO LOCAL COMMUNITY RESTRUCTURING

Marine invertebrates are at risk of extinction if climate changes outpace their ability to adapt to thermal stress, and cold-adapted taxa may be especially vulnerable because of their specialized physiologies and because their high-latitude distributions permit only limited poleward migration. Here, we use a database of 1437 early and middle Permian eastern Australian fossil collections from the Paleobiology Database to test for latitudinal range shifts, extinctions, and faunal invasion among high-latitude marine invertebrates during climate changes in the late Paleozoic ice age. Latitudinal range shifts are not apparent, either because genera were unable to migrate or, more likely, because sampling noise or the scale of analyses prevent their recognition. Extinction rates were moderately elevated during the largest climate shifts, however, possibly suggesting that at least some taxa were unable to respond to the rate or magnitude of climate change. Although recognition of range shifts within Australia is difficult, warm-water brachiopods, bivalves, and ammonoids invaded the region during pronounced warming in the Artinskian, highlighting the importance of temperature on faunal distribution. That faunal invasion was coincident with substantial restructuring of local paleocommunities, but both likely resulted from the common cause of increasing temperature rather than having a causal relationship. Temperature warming would have stressed cold-adapted stenotherms, triggering changes in local dominance and allowing immigration of warm-water taxa. These local and regional shifts in dominance and distribution imply that physiological stresses from even gradual climate change can be sufficient to trigger biotic change.

Weather effects on avian breeding performance and implications of climate change

The influence of recent climate change on the world's biota has manifested broadly, resulting in latitudinal range shifts, advancing dates of arrival of migrants and onset of breeding, and altered community relationships. Climate change elevates conservation concerns worldwide because it will likely exacerbate a broad range of identified threats to animal populations. In the past few decades, grassland birds have declined faster than other North American avifauna, largely due to habitat threats such as the intensification of agriculture. We examine the effects of local climatic variations on the breeding performance of a bird endemic to the shortgrass prairie, the Lark Bunting (Calamospiza melanocorys) and discuss the implications of our findings relative to future climate predictions. Clutch size, nest survival, and productivity all positively covaried with seasonal precipitation; yet relatively intense daily precipitation events temporarily depressed daily survival of nests. Nest survival was positively related to average temperatures during the breeding season. Declining summer precipitation may reduce the likelihood that Lark Buntings can maintain stable breeding populations in eastern Colorado although average temperature increases of up to 3 degrees C (within the range of this study) may ameliorate declines in survival expected with drier conditions. Historic climate variability in the Great Plains selects for a degree of vagility and opportunism rather than strong site fidelity and specific adaptation to local environments. These traits may lead to northerly shifts in distribution if climatic and habitat conditions become less favorable in the drying southern regions of the Great Plains. Distributional shifts in Lark Buntings could be constrained by future changes in land use, agricultural practices, or vegetative communities that result in further loss of shortgrass prairie habitats.

Thermal tolerance and the global redistribution of animals

Using a comprehensive data set of thermal tolerance limits, latitudinal range boundaries and latitudinal range shifts of cold-blooded animals, this study explores the likely consequences of climate change for the geographical redistribution of terrestrial and marine species at a global scale.

Climate change-driven species' range shifts filtered by photoperiodism

Shifts in the geographic distribution of species caused by climate change could detrimentally affect ecosystems and biodiversity. This Perspective highlights the importance of adaptations to day length in predicting the latitudinal range shifts of different species under global warming.

Failure to migrate: lack of tree range expansion in response to climate change

AbstractTree species are expected to track warming climate by shifting their ranges to higher latitudes or elevations, but current evidence of latitudinal range shifts for suites of species is largely indirect. In response to global warming, offspring of trees are predicted to have ranges extend beyond adults at leading edges and the opposite relationship at trailing edges. Large‐scale forest inventory data provide an opportunity to compare present latitudes of seedlings and adult trees at their range limits. Using theUSDAForest Service's Forest Inventory and Analysis data, we directly compared seedling and tree 5th and 95th percentile latitudes for 92 species in 30 longitudinal bands for 43 334 plots across the eastern United States. We further compared these latitudes with 20th century temperature and precipitation change and functional traits, including seed size and seed spread rate. Results suggest that 58.7% of the tree species examined show the pattern expected for a population undergoing range contraction, rather than expansion, at both northern and southern boundaries. Fewer species show a pattern consistent with a northward shift (20.7%) and fewer still with a southward shift (16.3%). Only 4.3% are consistent with expansion at both range limits. When compared with the 20th century climate changes that have occurred at the range boundaries themselves, there is no consistent evidence that population spread is greatest in areas where climate has changed most; nor are patterns related to seed size or dispersal characteristics. The fact that the majority of seedling extreme latitudes are less than those for adult trees may emphasize the lack of evidence for climate‐mediated migration, and should increase concerns for the risks posed by climate change.

Latitudinal range shifts in Australian flying‐foxes: A re‐evaluation

AbstractRecent range shifts towards higher latitudes have been reported for many animals and plants in the northern hemisphere, and are commonly attributed to changes in climate. Relatively little is known about such changes in the southern hemisphere, although it has been suggested that latitudinal distributions of the fruit‐batsPteropus alectoandPteropus poliocephaluschanged during the 20th century in response to climate change in eastern Australia. However, historical changes in these species distributions have not been examined systematically. In this study we obtained historical locality records from a wide range of sources (including banding and museum records, government wildlife databases and unpublished records), and filtered them for reliability and spatial accuracy. The latitudinal distribution of each species was compared between eight time‐periods (1843–1920, 1921–1950, five 10‐year intervals between 1950 and 2000, and 2001–2007), using analyses of both the filtered point data (P. alecto870 records,P. poliocephalus2506) and presence/absence data within 50 × 50 km grid cells. The results do not support the hypothesis that either species range is shifting in a manner driven by climate change. First, neither the northern or southern range limits ofP. poliocephalus(Mackay, Queensland and Melbourne, Victoria respectively) changed over time. Second,P. alecto's range limit extended southward by 1168 km (approximately 10.5 degrees latitude) during the twentieth century (from approximately Rockhampton, Queensland to Sydney, New South Wales). Within this zone of southward expansion (25–29°S), the percentage of total records that wereP. alectoincreased from 8% prior to 1950 to 49% in the early 2000s, and local count data showed that its abundance increased from several hundred to more than 10 000 individuals at specific roost sites, as range expansion progressed.Pteropus alectoexpanded southward at about 100 km/decade, compared with the 10–26 km/decade rate of isotherm change, and analyses of historical weather data show that the species consequently moved into recently‐colder regions than it had previously occupied. Neither climate change nor habitat change could provide simple explanations to explainP. alecto's observed rapid range shift. More generally, climate change should not be uncritically inferred as a primary driver of species range shifts without careful quantitative analyses.