Climate Envelope Models Research Articles

Tree rings reveal the transient risk of extinction hidden inside climate envelope forecasts

Given the importance of climate in shaping species' geographic distributions, climate change poses an existential threat to biodiversity. Climate envelope modeling, the predominant approach used to quantify this threat, presumes that individuals in populations respond to climate variability and change according to species-level responses inferred from spatial occurrence data-such that individuals at the cool edge of a species' distribution should benefit from warming (the "leading edge"), whereas individuals at the warm edge should suffer (the "trailing edge"). Using 1,558 tree-ring time series of an aridland pine (Pinus edulis) collected at 977 locations across the species' distribution, we found that trees everywhere grow less in warmer-than-average and drier-than-average years. Ubiquitous negative temperature sensitivity indicates that individuals across the entire distribution should suffer with warming-the entire distribution is a trailing edge. Species-level responses to spatial climate variation are opposite in sign to individual-scale responses to time-varying climate for approximately half the species' distribution with respect to temperature and the majority of the species' distribution with respect to precipitation. These findings, added to evidence from the literature for scale-dependent climate responses in hundreds of species, suggest that correlative, equilibrium-based range forecasts may fail to accurately represent how individuals in populations will be impacted by changing climate. A scale-dependent view of the impact of climate change on biodiversity highlights the transient risk of extinction hidden inside climate envelope forecasts and the importance of evolution in rescuing species from extinction whenever local climate variability and change exceeds individual-scale climate tolerances.

Stepwise Multidimensional Climate Envelop Modeling of Pitch Pine (Pinus rigida)

Understanding the intricate relationships between climate and vegetation remains a fundamental challenge in contemporary ecology. The ability to anticipate the specific climatic factors affecting different tree species and understand how they respond is crucial for mitigating the impacts of climate change on forested ecosystems. Additionally, quantitatively assessing habitat loss resulting from anthropogenic activities is essential for informed conservation efforts. Our objective is to evaluate the potential distribution of pitch pine (Pinus rigida) in North America and assess the associated habitat loss. To achieve this, we employ a stepwise multidimensional climate envelope modeling approach, comparing two data-intensive models—the Variable Interaction Model (VIM) and the Variable Non-Interaction Model (VNM). These models discern the influence of diverse combinations of climatic characteristics on the distribution of the species. Both VNM and VIM employ Shapley values for factor ranking during construction. VNM assumes independent effects, resulting in a hyperrectangle-shaped climate envelope, while VIM considers interactions, yielding a complex, data-driven multidimensional envelope. Data integration involves mining the US Forest Inventories and climatic data, encompassing 19 parameters. The results unequivocally highlight the superior predictive accuracy of VIM compared to the Variable Non-Interaction Model, VNM. The modeling approach developed in this study has the potential to enhance species distribution models for various tree species in the context of evolving climatic conditions.

The correspondence between the physiological cold tolerance and the distribution border of Mediterranean sandflies in Southeast Europe.

The distribution of sandflies is influenced by several climatic factors, like winter temperature limits, summer humidity, and drought. Only a few studies were performed to search for the connection between the physiological tolerance of sandflies and the result of the Climate Envelope Models projected distribution borders. It was studied how the depth of rodent burrows could determine the occurrence of five European Phlebotomus species based on their known physiological cold tolerances. The modelled distributions based on the monthly minimum temperatures showed notable differences by soil depth and species. The observed and modelled European distribution areas of sandflies according to - 20 cm soil depth showed good coincidence with the observed occurrences of Phlebotomus neglectus , Ph. papatasi , and Ph. perfiliewi in East-Central, Southeast, and East Europe. Also, a good coincidence was found in the case of the modelled and observed occurrences of Phlebotomus perniciosus in Western Europe. It can be concluded that in their north-eastern distribution borders, sandflies can overwinter in rabbit and rodent burrows at depths of - 20 cm below the surface. The physical cold tolerance of Ph. ariasi could be underestimated. In more than - 50 cm of depth, the stable and continuously cold environment of the shelters (mean temperature less than 10°C) could inhibit the post-winter diapause activation of sandflies in the northern regions.

Identifying conservation priority areas forNorth Americanbumble bee species inCanadaunder current and future climate scenarios

AbstractMany bumble bee species are declining globally from multiple threats including climate change. Identifying conservation priority areas with a changing climate will be important for conserving bumble bee species. Using systematic conservation planning, we identified priority areas for 44 bumble bee species in Canada under current and projected climates (year 2050). Conservation priority areas were identified as those that contained targeted amounts of each species predicted occurrence through climate envelope models, while minimizing the area cost of conserving the identified conservation priority areas. Conservation priority areas in the two periods were compared to established protected areas and land cover types to determine the area of current and future priority sites that are protected and the types of landscapes within priority areas. Notably, conservation priority areas were rarely within established protected areas. Priority areas were most often in croplands and grasslands, mainly within the mountain west, central and Southern Ontario, Northern Quebec, and Atlantic Canada under all climate scenarios. Conservation priority areas are predicted to increase in elevation and latitude with climate change. Our findings identify the most important regions in Canada for conserving bumble bee species under current and future climates including consistently selected future sites.

Climate Change and Animal Movement Integration in the Environmental Niche Model

Changing precipitation and temperature patterns due to climate change, shift ecological niches which pose a challenge for species. Furthermore, it is still unclear that if climate change faster than the speed of the species to move to more suitable environments. Climate Envelope models (GEMs) are used extensively in this matter to predict species geographical distribution. In this study, climate data and animal movement strategies integrated into the environmental niche model to analyze the successes of the species that have different movement strategies under the changing climate conditions. Four different movement strategies are formulized; lazy knowledge strategy (LKS), lazy no knowledge strategy (LNKS), proactive knowledge (PKS) and proactive no knowledge strategy (PNKS). In this study, mean annual temperature and annual precipitation data gathered for the RCP8.5 scenario from the HadGEM2-ES GCM model at a 10-minute resolution. Results show that the PKS has the highest survival rates which makes it the most successful strategy. Furthermore, the species with knowledge had performed higher survival rates than the species without knowledge due to their skill to find the most suitable cells around them. One-Way Anova test confirmed that there are significant differences between the strategies. Moreover, the analysis suggests that the species with knowledge of their environment have the most successful strategies for facing the climate change.

The dynamics of a changing Lutz spruce (Picea×lutzii) hybrid zone on the Kenai Peninsula, Alaska

We investigated the genetic makeup of Lutz spruce, a natural hybrid between white and Sitka spruce on the Kenai Peninsula, Alaska. Microsatellites indicate 72% of individuals sampled had predominantly white spruce ancestry, whereas 14% had predominantly Sitka spruce ancestry; some individuals classified as white spruce had Sitka spruce plastid genotypes. As Picea mitochondria are maternally inherited and plastids are paternally inherited, it appears that white spruce was the ancestral seed parent of nearly all spruce on the western peninsula, whereas Sitka spruce alleles originated from pollen. Pollen records show that white spruce colonized the western peninsula ∼8500 YBP from glacial refugium, whereas Sitka spruce arrived on the eastern peninsula ∼4000 YBP after migrating up the Pacific coast. Our data suggest that Sitka spruce colonization west of the Kenai Mountains may have occurred not via seed dispersal but by long distance transport of wind-borne pollen and subsequent hybridization with established white spruce populations. Hybridization was an important mechanism that allowed Sitka spruce to expand the leading edge of its range in response to historical climate change. As the climate continues to warm, climate envelope modeling suggests Lutz spruce may ultimately displace white spruce on the western peninsula even as Sitka spruce is constrained to the eastern peninsula where it will continue to hybridize.

Optimism for the Future Use of Environmental DNA (eDNA) to Study Global Climate Change

Optimism for the Future Use of Environmental <scp>DNA</scp> (<scp>eDNA</scp>) to Study Global Climate Change

Climate envelope analyses suggests significant rearrangements in the distribution ranges of Central European tree species

Key messageClimate envelope analysis of nine tree species shows that Fagus sylvatica L. and Picea abies H. Karst could lose 58% and 40% of their current distribution range. Quercus pubescens Willd and Quercus cerris L. may win areas equal with 47% and 43% of their current ranges. The ratio of poorly predictable areas increases by 105% in southern and south-eastern Europe.ContextClimate change requires adaptive forest management implementations. To achieve climate neutrality, we have to maintain and expand forest areas. Impact assessments have great importance.AimsThe study estimates the potential climate envelopes of nine European tree species for a past period (1961–1990) and for three future periods (2011–2040, 2041–2070, 2071–2100) under two emission scenarios (RCP4.5 and RCP8.5) based on the current species distribution.MethodsClimate envelopes were estimated simultaneously using the random forest method. Multi-resolution segmentation was used to determine the climatic characteristics of each species and their combinations. Models were limited to the geographical area within which the climatic conditions correspond to the climatic range of the training areas.ResultsResults showed remarkable changes in the extent of geographic areas of all the investigated species’ climate envelopes. Many of the tree species of Central Europe could lose significant portions of their distribution range. Adhering to the shift in climate, these tree species shift further north as well as towards higher altitudes.ConclusionEuropean forests face remarkable changes, and the results support climate envelope modelling as an important tool that provides guidelines for climate adaptation to identify threatened areas or to select source and destination areas for reproductive material.

Umbilicaria phaea var. coccinea: conservation status, variety rank, and secondary chemistry

Originally described from a single collection in northern California, Umbilicaria phaea var. coccinea has since been reported from additional sites in California, Oregon and Washington. Although relatively rare in all three states, there is currently no conservation status for U. phaea var. coccinea in California. Developing conservation strategies and status ranks requires a sound understanding of distribution, frequency, habitat requirements and taxonomic placement. Therefore, we evaluated distributions and constructed climate envelope models for both varieties of U. phaea. Umbilicaria phaea var. coccinea appears to be restricted to relatively small habitats within the range of U. phaea var. phaea and is only locally common in portions of the Klamath River watershed. To assess evolutionary relationships between the varieties, we evaluated four molecular loci: ITS2, LSU, Mcm7, and mtSSU. A combined phylogeny using maximum-likelihood and Bayesian inference indicated that U. phaea is monophyletic. Within the U. phaea clade, var. coccinea and var. phaea do not form mutually exclusive, monophyletic clades; instead, individuals are intermixed. Based on variation in pigment production, morphology, and geographic distribution, we recommend continued designation of U. phaea var. coccinea as a variety. To better understand the chemical diversity within U. phaea, we compared qualitative differences between secondary metabolite profiles of U. phaea var. phaea and U. phaea var. coccinea acetone extracts using ultraperformance-liquid chromatography high resolution tandem mass spectrometry in negative ion mode. UV spectroscopy, thin-layer chromatography and chemical spot testing were used to further characterize the compounds present. Overall, ten compounds were detected in extracts of U. phaea var. phaea and U. phaea var. coccinea. Five previously known chemical substances were identified in both U. phaea varieties including: orsellinic acid, lecanoric acid, hiascic acid, gyrophoric acid, and orsellinylgyrophorate, along with four unknown metabolites. One additional unknown substance whose chemical properties are consistent with a polyhydroxylated anthraquinone pigment was detected only in U. phaea var. coccinea. Given its rarity, chemical uniqueness, and distinct ecological association, U. phaea var. coccinea warrants a protected status throughout its range.

Climate change-induced background tree mortality is exacerbated towards the warm limits of the species ranges

Key messageAn influence of the recent changes in temperature or rainfall was demonstrated, increasing background tree mortality rates for 2/3 of the 12 studied tree species. Climate change-induced tree mortality was exacerbated towards the warm or dry limits of the species ranges, suggesting in these areas a progressive replacement by more xeric species.ContextDespite the identification of climate change effects on tree mortality in various biomes, the characterization of species-specific areas of vulnerability remains poorly understood.AimsWe sought to assess if the effects of temperature and rainfall changes on background tree mortality rates, which did not result from abrupt disturbances, were linked to climate change intensity only, or if they also depended on the tree’s location along climatic gradients.MethodsWe modelled background mortality for 12 of the most common European tree species using 265,056 trees including 4384 dead trees from the French national forest inventory. To explain mortality, we considered variables linked to tree characteristics, stand attributes, logging intensity and site environmental characteristics, and climate change effects.ResultsWe found an influence of temperature and rainfall changes on 9 species out of 12. For 8 of them, climate change-induced tree mortality was exacerbated towards the warm or dry limits of the species ranges.ConclusionThese results highlight that tree mortality varies according to the climate change intensity and the tree location along temperature and rainfall gradients. They strengthen the poleward and upward shifts of trees forecasted from climate envelope models for a large number of European tree species.

Climate change and the suitability of local and non‐local species for ecosystem restoration

SummaryRestoring damaged, degraded and destroyed forest ecosystems to a target state often follows a local‐is‐best approach. However, rapidly changing climates may result in the local species no longer being the best now or into the future. This raises questions about whether there is a need to consider emerging ecosystems that bring together local and non‐local species that have not historically co‐occurred to ensure climate‐resilience of restored forest ecosystems; or whether non‐regional species may be needed to support ecosystem functionality in some areas. In this study, I present an experimental framework to assist decision‐making by evaluating the suitability of local and non‐local native species for ecosystem restoration under current and predicted climates. I applied this framework using the Tasmanian Midlands, Australia, as a case study, focusing of the diverse eucalypt flora of the island. Three key findings emerged. Firstly, the climate of the Midlands has rapidly changed across this biodiversity hotspot over the last century, and current mean annual maximum temperatures are already tracking worse case climate change scenarios. Secondly, using a combination of climate envelope modelling and habitat suitability modelling, I identified the degree to which the Midlands region provides suitable climate habitat for a range of local and non‐localEucalyptusspecies now and into the future. Thirdly, although the Midlands is predicted to support suitable climate habitat for 82% of the regionally local eucalypt species now and into the future, it is predicted that the local populations of these least vulnerable species may be at risk of climate maladaptation, particularly in the northern regions of the Midlands. Models suggests that mixing local seed with non‐local seed sources currently occupying habitat with a climate that is predicted for the Midlands will be required. The study provides a basis for managers to consider the suitability of regionally local species and identify potential areas where local seed may need to be supplemented with non‐local seed for ecosystem restoration in the face of climate change.

Effects of geographic variation in host plant resources for a specialist herbivore's contemporary and future distribution

AbstractSpecies distributions are driven by abiotic and biotic factors, but the importance of variation in the availability and quality of critical resources is poorly understood. Disentangling the relative importance of these factors—abiotic environment, availability of critical resources, and resource quality—will be important to modeling species current distributions and responses to projected climate change. We address these questions using species distribution models (SDMs) for the western monarch butterfly population (Danaus plexippus), whose larvae feed exclusively on Asclepias species known for their heterogeneous distribution and variation in host quality. We modeled the distribution of 24 Asclepias species to compare three monarch distribution models with increasing levels of complexity: (1) a null model using only environmental factors (climate envelope model), (2) a model using environmental factors and Asclepias availability estimated as species richness, (3) and a model using environmental factors and Asclepias’ availability weighted by host plant quality as assessed through a greenhouse bioassay of larval performance. Asclepias models predicted that half of the Asclepias species will expand their ranges and shift toward higher latitudes, while half will contract. These patterns were uncorrelated with host plant quality. Among the three monarch models, the climate envelope model was the poorest performing. Models accounting for host plant availability performed best, while accounting for host plant quality did not improve model performance. The climate envelope model estimated more restrictive contemporary and future monarch ranges compared to both host plant models. Although all three models predicted future monarch range expansions, the projected future distributions varied among models. The climate envelope model predicted range expansions along the Pacific coast and contractions inland. In contrast, the host plant availability and quality models predicted range expansions in both of these regions and, as a result, 14% and 19% increases in distribution (respectively) relative to the climate envelope model. These models do not include other factors affecting monarch persistence. Nevertheless, our findings suggest that accounting for information on host plant availability and response to climate change is necessary to predict future species distributions, but that variation in the quality of those critical resources may be of secondary importance.

Grizzled Skippers stuck in the south: Population‐level responses of an early‐successional specialist butterfly to climate across its UK range over 40 years

AbstractAimClimate change has been predicted to facilitate poleward expansion of many early‐successional specialist invertebrates. The Grizzled Skipper, Pyrgus malvae, is a threatened butterfly in long‐term decline that has not met expectations of northern expansion in Britain, possibly indicating that climate change has not improved northern habitat suitability or that another driver (e.g. land use change) is masking its effects. Here, we explore the effect of climate on population size trends over four decades, and whether any regions show an improving population trend that may be a precursor to northern expansion. Examining detailed spatio‐temporal abundance data can reveal unexpected limitations to population growth that would not be detectable in widely used climate envelope models.LocationCentral and southern England.MethodsMixed models were used to investigate P. malvae population size in relation to time and monthly climate measures across its UK range since 1976, based on repeated transect walks.ResultsWe found that P. malvae population size declined more over time in the north and west of its UK range than in the south and east, and was negatively related to high December temperature and summer rainfall. However, the effect sizes of temperature and rainfall were minimal.Main ConclusionsThe last 40 years of climate change have not ameliorated climate suitability for P. malvae at its range edge, contrary to expectations from spatial‐only climate envelope models. The clear long‐term downward trends in population size are independent of climate change and we propose probably due to habitat deterioration. Our findings highlight potential hazards in predicting species range expansions from spatial models alone. Although some climate variables may be associated with a species’ distribution, other factors may be more dominant drivers of trends and therefore more useful predictors of range changes.

Potential distribution of two lynx species in europe under paleoclimatological scenarios and anthropogenic climate change scenarios

Background: Today’s European fauna was formed under the influence of Paleoclimatic change. The distribution of two wild cat species of Europe, Lynx pardinus and Lynx lynx, 22,000 and 6,000 years ago were determined by the MaxEnt method in relation to the Paleoclimatological scenarios (LGM and Mid-Holocene) and fossil records. Then, the current climate conditions and their distributions under the effect of anthropogenic climate change scenarios were analyzed with the current existence records. Results: It was determined that these two wild cats were distributed according to preys on which they specialized, rather than the climate change that lasted for thousands of years. It was observed that Lynx Pardinus, which specialized only on European rabbit hunting, could not expand its distribution from past to present. Lynx lynx, on the other hand, expanded its distribution throughout the Palearctic region and adapted to different ecosystem varieties by means of its specialization on many preys from mouse to moose. Based on the climate envelope model results created with the help of MaxEnt which considers anthropogenic climate change scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5 2070) and today’s data of two existing Lynx species, suitable habitats for L. pardinus will decrease and suitable habitats will emerge in Western France. L. lynx, on the other hand, will limit its wide distribution to the North, except for the Alps, the Carpathians and the Caucasus, which will serve as refugial areas. Conclusion: These results therefore require that measurements such as reducing climate change impacts over the next 50 years, protecting existing and potential habitats in advance, and reducing anthropogenic impact should be enforced.

Projected effects of climate change on the distribution and abundance of breeding waterfowl in Eastern Canada

As breeding areas are becoming warmer and wetter, climatic changes are likely to affect the distributions of millions of waterfowl in Eastern Canada. The objective of this study was to assess the potential effects of climate change on the breeding distribution and abundance of 12 common waterfowl species, by using a climate envelope modeling approach. Our response variables were species counts on 317 helicopter plots (25 km2) averaged over 22 years (1996–2017). We applied a covariate selection procedure to select the best subset of a panel of 170 climate covariates for each species, which we then used to fit quantile regression forest models. Climate change projections were applied to the waterfowl models to infer 2011–2100 abundances. From the projected abundances, we computed climate suitability indices that accounted for potential temporal mismatches between climate change and the biota, as well as the expected velocity of climate change. On average, with a maximum of 4 covariates per model, the variance explained was 41% for out-of-bag predictions. Overall, the magnitude of absolute projected changes peaked under the “high” greenhouse gas concentration trajectory (RCP8.5) and at the end of the century (2071–2100). Species-specific projections indicated that climate change would potentially increase the abundance and core distributions of 7/12 species, whereas 5/12 species would experience a decrease. In particular, large decreases were projected for Barrow’s goldeneye, an imperiled boreal cavity nester. Our spatially explicit indices of climate suitability deliver important information for targeting areas to preserve waterfowl, ecosystems, and the services they provide.

Reconstructing historical shifts in suitable habitat of Sceloporus lineages using phylogenetic niche modelling

AbstractAimWe tested whether we could detect geographical shifts in modelled‐suitable habitat. We aim to enhance phylogenetic niche models of past suitable habitats for Sceloporus lineages by integrating modern and fossil occurrences with ecological and phylogenetic comparative modelling methods. Specifically, we hypothesized that our integrated approach is sensitive enough to detect geographical shifts in suitable habitat between lineages and through evolutionary time.LocationNorth America.TaxonSceloporus lizards.MethodsWe used extant and fossil occurrence data, general circulation models of palaeoclimate, climate envelope modelling and phylogenetic comparative methods to reconstruct past suitable climates for Sceloporus lizards over the last 20 million years, and then visualized the geographical locations of individual lineages using multivariate environmental similarity surfaces (MESS) maps.ResultsWe were able to reconstruct ancestral suitable climate for Sceloporus lineages with sufficient resolution to identify shifts in geographical location between lineages. We found that large shifts in climate regimes drove the expansion and contraction of suitable habitat through time. We found a positive association between tectonic events, like mountain uplift, and lineage diversification in the Sceloporus clade. Mountain uplift also facilitated the emergence of open grassland habitat, which excluded many Sceloporus species.Main conclusionsOur approach was sensitive enough to detect differences in geographical location of suitable habitat across lineages and through evolutionary time. Doing so is a critical first step to tracking the evolutionary ecology of individual taxa over long periods of evolutionary time, and to inferring which species co‐existed in which locations. Such inferences would allow for more precise predictions of current and future ecological needs for conservation efforts, and to inform efforts to mitigate climate change.

Potential distribution and the habitat suitability of the African mustard (Brassica tournefortii) in Tunisia in the context of climate change

The global warming resulting from anthropogenic activities is considered a major threat for the biodiversity in arid and semi-arid regions worldwide. North African countries in western Mediterranean basin, including Tunisia, are expected to experience strong rainfall drop and temperature increase in the next few decades, interrogating the geographical distribution of many plant species in the context of future climate change. Here, ecologically based quantitative climatic envelope model was developed using Maximum Entropy (MaxEnt) to predict current and future distribution of Brassica tournefortii in Tunisia. The data inputs were composed of the species occurrence data and nineteen climatic layers varied over time in line with the predictions created from the global warming scenarios (RCP 4.5 and RCP 6.0) by 2050 and 2070. Using nine uncorrelated variables fitting very well our MaxEnt model, results revealed that the distribution of B. tournefortii was mainly influenced by precipitation-related variables, which contributed with 79.58% in the model, whereas a small contribution was attributed to temperature-related variables (18.20%). Moreover, a noticeable reduction in the current species’ range was recorded, compared with that observed during Last Glacial Maximum (LGM). However, the results suggested a small increase in the areas of very highly, highly, and moderately suitable habitats for the species (0.2, 0.28, and 2.41%, respectively) by 2070 under RCP 6.0. Importantly, we found that the habitat suitability of the species, when applying a climate envelope model, was optimal both along the coastal and the dry South-Western zones of the study area. Overall, the results indicated that B. tournefortii exhibits a great tolerance to severe abiotic constraints of southern Tunisia and seemed to be able to survive under future environmental conditions of its adaptation range. These findings can be used to design reasonable exploitation strategies in order to benefit from the ecological and economical values of B. tournefortii.

Drivers of Holocene palsa distribution in North America

Palsas and peat plateaus are climatically sensitive landforms in permafrost peatlands. Climate envelope models have previously related palsa/peat plateau distributions in Europe to modern climate, but similar bioclimatic modelling has not been attempted for North America. Recent climate change has rendered many palsas/peat plateaus in this region, and their valuable carbon stores, vulnerable. We fitted a binary logistic regression model to predict palsa/peat plateau presence for North America by relating the distribution of 352 extant landforms to gridded modern climate data. Our model accurately classified 85.3% of grid cells that contain observed palsas/peat plateaus and 77.1% of grid cells without observed palsas/peat plateaus. The model indicates that modern North American palsas/peat plateaus are supported by cold, dry climates with large seasonal temperature ranges and mild growing seasons. We used palaeoclimate simulations from a general circulation model to simulate Holocene distributions of palsas/peat plateaus at 500-year intervals. We constrained these outputs with timings of peat initiation, deglaciation, and postglacial drainage across the continent. Our palaeoclimate simulations indicate that this climate envelope remained stationary in western North America throughout the Holocene, but further east it migrated northwards during 11.5–6.0 ka BP. However, palsa extents in eastern North America were restricted from following this moving climate envelope by late deglaciation, drainage and peat initiation. We validated our Holocene simulations against available palaeoecological records and whilst they agree that permafrost peatlands aggraded earliest in western North America, our simulations contest previous suggestions that late permafrost aggradation in central Canada was climatically-driven.

Climate Envelope Models of Kalopanax septemlobus and Phellodendron amurense var. sachalinense in the Insular Part of the Russian Far East

The expansion of the range of Kalopanaxseptemlobus and Phellodendronamurense var. sachalinense on Sakhalin Island and the Kuril Islands as a result of global climate changes is studied. Climate envelope models were performed using the maximum entropy method (MaxEnt v. 3.3.3) and WorldClim v. 1.4 data. It is noted that these models predict an increase in the area of habitats with suitable climate conditions for K. septemlobus and P. amurense var. sachalinense by 9.55 and 14.65% of the total area of the region, respectively, by 2050 as a result of the increase in the average annual temperature by 3.9°C in this region (RCP2.6 scenario); according to the radical scenario, the total projected area with suitable conditions will increase by 45.86% for K. septemlobus and 66.24% for P. amurense with a temperature increase by 5.2°C (RCP8.5 scenario).

Microsites and Climate Zones: Seedling Regeneration in the Alpine Treeline Ecotone Worldwide

Microsites, local features having the potential to alter the environment for seedling regeneration, may help to define likely trends in high-elevation forest regeneration pattern. Although multiple microsites may exist in any alpine treeline ecotone (ATE) on any continent, some microsites appear to enhance density of seedling regeneration better than others. Known seedling regeneration stresses in the ATE include low temperature, low substrate moisture, high radiation, drought, wind, and both high and low snowfall amount. Relationships among various microsite types, annual temperature, annual precipitation, and tree genera groups were assessed by synthesizing 52 studies from 26 countries spanning six continents. By categorization of four main microsite types (convex, concave, object, and wood) by mean annual precipitation and temperature, four major climatic zone associations were distinguished: cold &amp; dry, cold &amp; wet, warm &amp; dry, warm &amp; wet. Successful tree recruitment varied among microsite types and by climatic zones. In general, elevated convex sites and/or decayed wood facilitated earlier snow melt for seedlings located in cold &amp; wet climates with abundant snowfall, depressions or concave sites enhanced summer moisture and protected seedlings from wind chill exposure for seedlings growing in cold &amp; dry locations, and objects protected seedlings from excessive radiation and wind in warm &amp; dry high locations. Our study results suggest that climate change will most benefit seedling regeneration in cold &amp; wet locations and will most limit seedling regeneration in warm &amp; dry locations given likely increases in fire and drought. Study results suggest that high-elevation mountain forests with water-limited growing seasons are likely to experience recruitment declines or, at best, no new recruitment advantage as climate warms. Climate envelope models, generally focusing on adult trees rather than seedling requirements, often assume that a warming climate will move tree species upward. Study results suggest that climate models may benefit from more physically-based considerations of microsites, climate, and current seedling regeneration limitations.