Range Shifts Research Articles

Accounting for dispersal and intraspecific variation in forecasts of species distribution under climate change

Abstract Dispersal and local adaptation play an important role in driving species distributions under climate change. Many studies aim to estimate relationships between species occurrences and environmental variables to predict range shift and biodiversity loss, ignoring dispersal and intraspecific variation contributing to complex spatial and temporal dynamics. We accounted for dispersal and intraspecific variation in forecasts of species distribution under climate change with species distribution models (SDMs) using two cold‐adapted, low‐dispersal Platycerus species (Coleoptera: Lucanidae), each with distinct subspecies distributions, as focus species. The results showed that the subspecies‐level model performed significantly better than the species‐level model when considering dispersal constraints in SDMs. Whether or not dispersal or intraspecific variation is accounted for, the predicted species range of Platycerus albisomni is expected to decrease in the future. For Platycerus takakuwai, accounting for dispersal constraints in SDMs indicated that its potential distribution area would increase at the subspecies level under climate change, but decrease at the species level. These divergent results show that SDMs at the subspecies level can detect impacts of climate change that may be overlooked in species‐level models. Therefore, models that consider intraspecific variation and dispersal constraints may provide a more realistic perspective on the impacts of climate change. Because accurate mapping of potential habitats is needed for conservation purposes, demographic studies should include dispersal explicitly and explore how and when intraspecific variation in dispersal affects local population dynamics. This approach could help evaluate species' habitat shifts, thus enabling suitable conservation strategies.

Projected distribution of the westernmost subpopulation of Assamese macaques (Macaca assamensis pelops) under climate change: conservation implications of a threatened population

Anthropogenic climate change can have a negative impact on the distribution of habitat specialist species with narrow distributional ranges. Among the many areas around the world affected by climate change, the Himalayan region in particular is experiencing marked effects of global warming on its climatic patterns and life forms. This study assessed the current distribution of Assamese macaques (Macaca assamensis) in western Nepal, and projected their likely distribution (via habitat suitability modeling) for the years 2050 and 2070 under the two most plausible greenhouse gas emission scenarios (RCP4.5 and RCP6.0). We recorded a total of 159 Assamese macaques belonging to 10 groups (nine of them residing outside of protected area networks) between 684m and 2550m asl in western Nepal. Climatic niche modeling predicted that 37.03% (25,114 km2) of the total area of western Nepal (67,813 km2) represented suitable habitat of the species, the majority of which ranged between 1000 m and 2000 m asl. Future projections of the current climatic niche of the Assamese macaques revealed a consistent decrease in the suitable habitat for 2050 and 2070 in both of the greenhouse emission scenarios tested. With the RCP6.0 scenario, almost 57% of the current highly suitable habitat would be lost by 2070 with remaining suitable habitat shifted towards higher elevations. The loss of habitat directly affects the species survival and the range shift towards higher elevation exposes them to new areas for conflict with humans. Therefore, the Assamese macaque population in western Nepal requires a high conservation priority with the establishment of new protected areas.

Integration of hybrid score functions to design new adaptive EWMA control chart to monitor the process mean shift

Small-to-moderate shifts in the process parameters can be detected using the traditional Exponentially Weighted Moving Average (EWMA) control chart. The classical EWMA control chart's parameter helps only to identify the specific size of the shift. However, various shifts occur in real-world processes, so the conventional EWMA control chart performs inefficiently for off-target shifts. This problem has been confronted by applying an adaptive EWMA (AEWMA) control chart, an advanced version of the classical EWMA control chart. The score functions are utilized to design the AEWMA control chart. Generally, the Huber and Bi-square (score) functions have unique characteristics, such as monotone and redescended, respectively.There has not been any investigation into the simultaneous and/or joint deployment of score functions. So, by taking this point as motivation, this study aims to propose a new score function by blending the Huber and Bi-square characteristics into one hybrid formulation and then utilize it to design a new AEWMA control chart to monitor different sizes of the shift in the process location parameter. To evaluate the proposed control chart performance against other control charts, Monte Carlo simulation is applied to obtain the run length properties under zero-state and steady-state environments. Performance measures, such as average run length, standard deviation of run length, and median of run length, are considered to evaluate the performance at a single shift. In contrast, extra quadratic loss, relative average run length, and performance comparison index are utilized to evaluate effectiveness for a specific range of shifts. The comparison based on performance measures and visual presentation reveals the superiority of the proposed control chart. Besides, the proposed control chart is employed in the real-world chemical engineering process industry problem, demonstrating excellent detection ability of anomalies in air pollutant data. The comparison based on performance measures and visual presentation reveals the good performance of the proposed control chart.

Advancing and retreating fronts in a changing climate: a percolation model of range shifts

Climate change causes considerable shifts in the geographic distribution of species worldwide. Most data on range movements, however, derive from relatively short periods, within which it is difficult to distinguish directional shifts from random fluctuations. For detecting a shift, it is indispensable to delineate the range precisely. We propose a new method for the delineation based on percolation theory. We suggest marking the boundary between the connected and fragmented occurrence of the species (the hull). We demonstrate the advantages of this connectivity‐based method on simulated examples in which a metapopulation is advancing vs retreating along an environmental gradient with different velocities. The simulations show that the hull is a fractal and has the same dimension (7/4) even when the front is advancing or retreating relatively fast, compared to the generation time. It is particularly robust in the retreating (trailing) edge. Accordingly, we propose marking the range edge at the mean position of the hull, the 'connectivity limit' of the species. Theoretical considerations suggest that the position of the connectivity limit is statistically more reliable than those limits that are delineated according to the outermost occurrences, and the connectivity‐based method is broadly applicable to real‐life data.

Integrated Approach Improves Monitoring of Wintering Red Kites in Central Europe

ABSTRACT The Red Kite (Milvus milvus) is a common raptor in suitable areas of Austria, the Czech Republic, and Slovakia during the nonbreeding season. However, the exact number of birds wintering in these countries remains unknown. Through an integrated approach using satellite telemetry, direct field surveys at nocturnal roosts, and citizen science databases, we estimated the wintering population of Red Kites in this area during the winter of 2020/2021. Based on three surveys taking place at the beginning (28 November 2020), middle (9 January 2021), and end (5 February 2021) of winter, respectively, we counted 566, 558, and 536 Red Kites. The observations from online citizen science databases mostly appeared to correspond with the area of communal roost sites. Using our combined approach, the estimates of wintering Red Kites were determined as minimum numbers in the study area. A comparison of historical data (from the second half of the 20th and beginning of the 21st centuries, respectively) and our own results suggests that the wintering population of Red Kites in the study area has increased substantially. This dynamic could be caused by changes in climatic conditions, a shift of the birds' breeding range in Europe, changes in migration behavior and/or food availability, and/or conservation efforts.

Climate Change and Anthropogenic Factors Are Influencing the Loss of Habitats and Emerging Human–Elephant Conflict in the Namib Desert

Climate change and anthropogenic factors’ impact on habitat loss is a growing problem that is influencing unsustainable wildlife local-population home range shifts and triggering an increase in human–wildlife conflict (HWC). Yet, keystone species involved in HWC such as elephants play a vital role in nature-based ecosystem services and have important economic and cultural value to the people that are living with them. To understand how climate change and anthropogenic factors affect habitat loss and elephants’ home range shift, the movement of Namib desert-dwelling elephants was monitored and observed in the Ugab River basin between February 2018 and November 2020 at fortnight intervals. There are 87 elephants in the Ugab River basin that are distributed into two subpopulations: desert-dwelling elephants (N = 28) and semi-desert-dwelling elephants (N = 59). To achieve the objective of the study, land cover change, elephant movement, rainfall, and temperature data were analysed using ArcGIS spatial and statistical tools, such as image analysis, optimised hot spot analysis (OHSA), and cost distance analysis, to distinguish habitat vegetation changes and home range shifts and how these link to emerging human–elephant conflict (HEC) hot spots. Human farming activities, poor rainfall, and frequent droughts are responsible for the loss of habitat of around 73.0% in the lower catchment of the ephemeral river streams; therefore, the urgency of conserving and sustaining these habitats and desert-dwelling elephants is discussed here.

Hygromechanical Behavior of Polyamide 6.6: Experiments and Modeling.

This paper investigates water absorption in polyamide 6.6 and the resulting hygroscopic swelling and changes in mechanical properties. First, sorption and swelling experiments on specimens from injection molded plates are presented. The observed swelling behavior is dependent on the melt flow direction of the injection molding process. Additionally, thermal analysis and mechanical tensile tests were performed for different conditioning states. The water sorption is accompanied by a decrease in the glass transition temperature and a significant reduction in stiffness and strength. Next, a sequentially coupled modeling approach is presented. A nonlinear diffusion model is followed by mechanical simulations accounting for swelling and concentration-dependent properties. For the mechanical properties, the notion of a "gap" temperature caused by the shift of the glass transition range due to water-induced plasticization is employed. This model enables the computation of local moisture concentration fields and the resultant swelling and changes in stress-strain behavior.

Multitemporal Land Use and Cover Analysis Coupled with Climatic Change Scenarios to Protect the Endangered Taxon Asphodelus bento-rainhae subsp. bento-rainhae.

Climate change and land use and land cover (LULC) change are impacting the species' geographic distribution, causing range shifts and reducing suitable habitats. Asphodelus bento-rainhae subsp. bento-rainhae (AbR) is an endangered endemic plant restricted to Serra da Gardunha (Portugal), and knowledge of those changes will help to design conservation measures. MaxEnt was used to model AbR's current distribution and project it into the future, 2050, using the Shared Socioeconomic Pathway SSP3-7. The Portuguese LULC maps from 1951-1980, 1995, 2007, and 2018 were used to assess and quantify LULC changes over time. The results showed that the AbR current predicted distribution matches its actual known distribution, which will not be affected by future predicted climate change. The significant LULC changes were observed during the study periods 1951-1980 to 2018, particularly between 1951-1980 and 1995. Scrubland and Agriculture decreased by 5% and 2.5%, respectively, and Forests increased by 4% in the study area. In the occurrence area, Agriculture increased, and Forests decreased between 1980 and 2018, due to Orchard expansion (34%) and declines in Chestnut (16.9%) and Pine (11%) areas, respectively. The use of species distribution models and the LULC change analysis contributed to understanding current and future species distribution. The LULC changes will have a significant impact on future species distribution. To prevent the extinction of this endemic species in the future, it is crucial to implement conservation measures, namely species monitoring, replantation, and germplasm conservation, in addition to guidelines for habitat conservation.

Potential upslope and latitudinal range shifts for Andean potato weevils Premnotrypes species, in the tropical Andes of South America

Premnotrypes is a weevil species complex that occurs in the high Andes of South America. Most of the species are considered to be crop pests, associated with potato production, thus constituting a major potential pest in Andean regions. Changes in temperature patterns affect the ontogeny and physiology of crop pests directly, which will in turn affect the pest populations. Here, we used ecological niche modeling (ENM) to assess the potential geographic distribution of seven economically important Premnotrypes species under current conditions and two under future scenarios of conditions scenarios (SSP 4.5 and SPP 8.5) for 2050 and 2090. Current-time niche models predicted suitable areas across the tropical Andes. For P. vorax, ENMs showed suitable areas across the Andes of Peru, Colombia, and Venezuela. For P. lathithorax, ENMs showed suitable areas only in the Andes of Peru and Bolivia. Finally, for P. solaniperda, P. solanivorax, P. pusillus, P. suturicallus, and P. percei, ENMs indicated suitable areas across central and southeastern Peru. Under future conditions, for all seven species, ENMs anticipated range shifts to higher latitudes and upslope migration, thus reducing suitable areas in the eastern Andes. Our novel results offer a guide for designing monitoring programs for potato pests and developing optimal pest control and mitigation strategies.

Climate change induces habitat shifts and overlaps among carnivores in an arid and semi-arid ecosystem

Distribution range shift is inevitable for many species as climate change continues to shape and alter their habitat. Predicting where these shifts occur can help us know what to anticipate and thus design better programs and strategies for species management. Due to projected extreme climate change in many arid and semi-arid ecosystems, we hypothesized that many species adapted to these systems would experience considerable spatial shifts. To test our hypothesis, we modelled current and future habitats under different climate scenarios for three iconic carnivores (grey wolf, golden jackal, and striped hyaena) in central of Iran and calculated their spatial overlaps. Our models predict that although each species responds differently to environmental changes, their habitats are heavily influenced by climatic variables, water resources, and roads. Our models also suggest that the high-quality habitats of grey wolves and striped hyaenas will probably expand, while for golden jackals, it will decrease. Significant spatial overlap of highly suitable habitat will exist among the species, particularly between the golden jackal and the striped hyaena. The overlapped highly suitable areas for all species cover between 9% to 10% of the whole region at present and in the future. Because of the spatial overlap and decrease in rainfall in the future, the three carnivores may face competition due to climate change. Our findings are crucial for establishing conservation areas that will conserve carnivore species in the future.

Predicted range shifts of alien tree species in Europe

Alien tree species are considered both a threat to nature conservation and a base for forest management. We compiled species occurrences from biodiversity databases, forest inventories, and literature data. We modeled the availability of potential niches using the MaxEnt method and bioclimatic variables for current conditions, 2041–2060, and 2061–2080 periods. We used four climate scenarios: SSP126, SSP245, SSP370, and SSP485. The results confirm our hypotheses that, (i) coniferous species will contract, and deciduous trees will expand their climatic niche, (ii) a significant part of the areas where the studied species currently occur will be outside their climatic optimum in the coming decades; (iii) changes in the climatic optimum distribution will be greater in the 2041–2060 period than in 2061–2080. These predicted shifts are relevant for evidence-based management in sites already occupied by the studied alien trees. Our results are also relevant to the development of prevention and early detection measures in areas predicted to become climatically suitable for the studied species.

Middle Holocene Lithic Technological Organization and Upland Land Use in the Upper Susitna River Basin, Alaska

ABSTRACT The middle Holocene period is marked by an apparent increase in the use of upland subsistence resources across North America. This pattern has also been observed in the uplands of central Alaska; however, we have limited understanding of the nature of upland hunter-gatherer land-use strategies during this time. This study presents a lithic technological organization analysis of three middle Holocene sites in the upper Susitna River basin, central Alaska Range, to evaluate middle Holocene land-use strategies. The Middle Holocene lithic assemblages presented here have characteristics of a low mobility land-use system in contrast with preceding periods. An important driver of middle Holocene upland land-use intensification may have been a warming climate and associated shift in vegetation patterns and caribou range. Understanding the intensity with which hunter-gatherers in the past utilized upland landscapes has implications for understanding ecological change in marginal ecosystems.

Can Bengal Tiger (Panthera tigris tigris) endure the future climate and land use change scenario in the East Himalayan Region? Perspective from a multiple model framework.

Large mammals are susceptible to land use and climate change, unless they are safeguarded within large, protected areas. It is crucial to comprehend the effects of these changes on mammals to develop a conservation plan. We identified ecological hotspots that can sustain an ecosystem for the endangered Bengal tiger (Panthera tigris tigris), an umbrella species. We developed three distinct ensemble species distribution models (SDMs) for the Bengal tiger in the Indian East Himalayan Region (IEHR). The first model served as the baseline and considered habitat type, climate, land cover, and anthropogenic threats. The second model focused on climate, land use, and anthropogenic threats, the third model focused on climate variables. We projected the second and third models onto two future climate scenarios: RCP 4.5 and RCP 8.5. We evaluated the threats possess to protected areas within eco-sensitive zone based on the potential tiger habitat. Finally, we compared the potential habitat with the IUCN tiger range. Our study revealed that the Brahmaputra valley will serve as the primary habitat for tigers in the future. However, considering the projected severe climate scenarios, it is anticipated that tigers will undergo a range shift towards the north and east, especially in high-altitude regions. Very high conservation priority areas, which make up 3.4% of the total area, are predominantly located in the riverine corridor of Assam. High conservation priority areas, which make up 5.5% of total area are located in Assam and Arunachal Pradesh. It is important to note that conservation priority areas outside of protected areas pose a greater threat to tigers. We recommend reassessing the IUCN Red List's assigned range map for tigers in the IEHR, as it is over-predicted. Our study has led us to conclude both land use and climate change possess threats to the future habitat of tigers. The outcomes of our study will provide crucial information on identifying habitat hotspots and facilitate appropriate conservation planning efforts.

Limited range shifting in biocrusts despite climate warming: A 25‐year resurvey

Abstract The ranges of many species globally have already shifted to maintain climatic equilibrium in the face of climate change. Biocrusts—soil surface dwelling communities of lichens, bryophytes and microbes—play important functional roles in many ecosystems, particularly in drylands. Compared to better studied animal and plant taxa, dryland biocrusts have different establishment requirements and have never been assessed for historical range shifts. Here, we revisited the sites (N = 204) of a 25‐year‐old biocrust survey across a large area (400,000 km2) of drylands in south‐eastern Australia. We used quadratic models to quantify changes in the climate niches of 15 lichen, eight moss and five liverwort taxa, as well as biocrust cover and richness. Our models showed that the observed climatic niches of most taxa have become hotter and drier in the past quarter century, yet the responses of the vast majority of taxa are consistent with remaining in the same geographic space. A similar pattern was observed at the community level, where the peak of biocrust cover and richness now occurs in a hotter, drier environment. Notable exceptions were the liverwort Riccia lamellosa and lichens in the genera Cladonia and Xanthoparmelia, which showed signs of contraction at their arid range edges. Unlike more mobile taxa, most biocrust species have yet to shift geographically and may already be lagging behind the pace of climate change. One explanation for the mortality lag is that long‐term climate variability in the system is extensive, which may have selected for the ability to withstand multi‐year warm periods as long as there is an eventual return to milder conditions. However, no forecasts of future climate include a return to milder conditions, suggesting there will be an eventual loss of ecosystem multifunctionality at the contracting front. Expansion lags are most likely due to delays in the mortality of competing vascular plants. Synthesis: Our study provides a valuable contribution to the knowledge of range shifts in understudied taxa and highlights a future need to promote the expansion of biocrusts to maintain the provision of ecosystem functions and services across their range.

Accounting for trait variability and coordination in predictions of drought-induced range shifts in woody plants.

Functional traits offer a promising avenue to improve predictions of species range shifts under climate change, which will entail warmer and often drier conditions. Although the conceptual foundation linking traits with plant performance and range shifts appears solid, the predictive ability of individual traits remains generally low. In this review, we address this apparent paradox, emphasizing examples of woody plants and traits associated with drought responses at the species' rear edge. Low predictive ability reflects the fact not only that range dynamics tend to be complex and multifactorial, as well as uncertainty in the identification of relevant traits and limited data availability, but also that trait effects are scale- and context-dependent. The latter results from the complex interactions among traits (e.g. compensatory effects) and between them and the environment (e.g. exposure), which ultimately determine persistence and colonization capacity. To confront this complexity, a more balanced coverage of the main functional dimensions involved (stress tolerance, resource use, regeneration and dispersal) is needed, and modelling approaches must be developed that explicitly account for: trait coordination in a hierarchical context; trait variability in space and time and its relationship with exposure; and the effect of biotic interactions in an ecological community context.

Sea level rise adaptation pushes an insular endemic rodent closer to extinction

Understanding how species will respond to a rapidly changing global climate is requisite to conserving biodiversity. Though habitat losses from human development and land use change remain the most critical threats to biodiversity globally, some regions, such as low-lying islands, are particularly vulnerable to the effects of climate change. Despite this vulnerability, there may be opportunities for imperiled species on islands to adapt to the effects of climate-induced sea level rise. To understand how the response to rising seas may influence the amount of future habitat, we investigated shifts in the elevational range of the endangered silver rice rat (Oryzomys palustris natator; hereafter “rice rat”), a species endemic to tidal environments of the Lower Florida Keys, USA. We quantified fine-scale habitat use using radio telemetry of collared animals, first in 2004, and again in 2021, thus spanning a 17-year period during which the local sea level rose by 0.142 m. We observed a shift in the elevational range limits of rice rats which closely mirrored the rise in sea level, and that this apparent ability to adapt to rising sea level decreased the extent of habitat loss in subsequent decades. However, over longer time scales (~ 100 yrs), the extent of habitat loss from sea level rise outpaced rice rats’ ability to adapt. As such, the conservation of biodiversity on low-lying islands hinges on the ability of the global community to decrease anthropogenic greenhouse gas emissions and mitigate the associated consequences for the global climate. Otherwise, conservation practitioners will be increasingly forced to make difficult decisions about how to conserve imperiled species on low-lying islands.

A melting-pot for Pterodroma petrels on Rapa Nui: ecological divergence and reproductive isolation in a contact zone

Speciation is thought to depend on general ecological segregation rather than on strict allopatry in species with planetary-scale foraging ranges, such as Pterodroma petrels. Separation in both breeding islands and foraging grounds are generally considered to be the conditions for prezygotic isolation. However, it is unclear how both can be maintained in a context of ongoing distributional range shifts due to global change, with range contractions and expansions caused by changing land use in breeding territories and oceanographic conditions impacting productivity areas. In this context, we expect that wherever the fragile balance of allopatric segregation breaks down, gene flow may be re-established across the borders of what is currently considered separated species. In these “melting pot” areas, fine-scale ecological differentiation is likely the only force opposing panmixia in otherwise highly similar organisms. In this study, we focus on six Polynesian Pterodroma species currently found on Motu Nui, a protected islet offshore of Rapa Nui (Easter Island), four of which have likely extended their breeding range to that island recently. To understand the fine-scale interaction between these closely-related species in their new contact zone, we used an integrative approach combining ecological and genetic methods, including morphometric, bioacoustics, stable isotope niche reconstruction, breeding site characterisation, phenology traits, and both nuclear and mitochondrial DNA markers. We found that significant amounts of gene flow occur across what is currently considered species boundaries, sometimes questioning the relevance of the accepted species classification. Interestingly, our results indicate that multivariate ecological distance between individuals in a group of closely related species (P. alba, P. atrata, P. heraldica, and P. neglecta) is a relevant predictor of gene flow intensity, while more distant species such as P. ultima and P. nigripennis seem to maintain reproductive isolation. Thus, the case of Pterodroma petrels supports the idea that incomplete allopatric speciation processes may be halted or even reversed on a secondary contact zone. Beyond their direct taxonomical relevance, our results underline the importance of considering fine ecological structures for biodiversity mapping and conservation policies.

Past climate-driven range shifts structuring intraspecific biodiversity levels of the giant kelp (Macrocystis pyrifera) at global scales

The paradigm of past climate-driven range shifts structuring the distribution of marine intraspecific biodiversity lacks replication in biological models exposed to comparable limiting conditions in independent regions. This may lead to confounding effects unlinked to climate drivers. We aim to fill in this gap by asking whether the global distribution of intraspecific biodiversity of giant kelp (Macrocystis pyrifera) is explained by past climate changes occurring across the two hemispheres. We compared the species’ population genetic diversity and structure inferred with microsatellite markers, with range shifts and long-term refugial regions predicted with species distribution modelling (SDM) from the last glacial maximum (LGM) to the present. The broad antitropical distribution of Macrocystis pyrifera is composed by six significantly differentiated genetic groups, for which current genetic diversity levels match the expectations of past climate changes. Range shifts from the LGM to the present structured low latitude refugial regions where genetic relics with higher and unique diversity were found (particularly in the Channel Islands of California and in Peru), while post-glacial expansions following ~ 40% range contraction explained extensive regions with homogenous reduced diversity. The estimated effect of past climate-driven range shifts was comparable between hemispheres, largely demonstrating that the distribution of intraspecific marine biodiversity can be structured by comparable evolutionary forces across the global ocean. Additionally, the differentiation and endemicity of regional genetic groups, confers high conservation value to these localized intraspecific biodiversity hotspots of giant kelp forests.

Impact of Faculty Incentivization on Resident Evaluations.

In the Program Requirements for Graduate Medical Education in Emergency Medicine, the Accreditation Council for Graduate Medical Education requires frequent and routine feedback. It is a common challenge for program leadership to obtain adequate and effective summative evaluations. This is a retrospective, case-crossover, interventional study conducted in an academic medical center. This study occurred over a two-year period, with an intervention between years one and two. Throughout year two of the study, faculty incentive compensation was linked to completion of end-of-shift evaluations. We compared pre- an post-implementation data using paired sample t-tests with the significance level P < .05 applied. After implementation of the incentive metric there was an increase in the number of total evaluations by 42% (P = .001). The mean number of evaluations submitted by each faculty per shift increased from 0.45 to 0.86 (SD 0.56, P < .001). Overall, 32 of the 38 faculty members (84.2%) had an increase in the number of evaluations submitted per shift during the intervention period with an average increase of 0.5 evaluations per shift (range 0.01-1.54). Incentivizing faculty to submit resident evaluations through use of bonus compensation increased the number of evaluations at our institution. This information may be applied by other programs to increase resident evaluations.

West coast U.S. tree species show stronger evidence for shifts in density than range

Climate change is associated with shifts in the geographic range of trees and other taxa globally. In North America and elsewhere tree species’ ranges are expected to shift at rates of meters to kilometers annually. However, empirically detecting a shift in the range of a tree species may be difficult due to the lack of quality long-term regional or national data. Evidence of range shifts is further confounded by apparently contradictory findings from separate studies that use different methods to evaluate species responses. In this study we examine U.S. Forest Service Forest Inventory Analysis plot revisit data in the states of California, Oregon, and Washington to examine shifts in the ranges and densities of tree species relative to values of temperature, precipitation, and maximum and minimum vapor pressure deficit (VPD) using a design-based estimation technique. We also examine changes in these four climate variables for years before and between plot visits. We found that the ranges for 49 tree species seldom shifted in the 10-year period of plot remeasurements, but depending on the climate variable considered, between seven and ten out of 30 species did exhibit density shifts, generally increasing in plots that were initially cooler, drier, and had lower VPD. Overall, plots increased in temperature and VPD values between time periods while they generally experienced declines in precipitation. These changes were frequently not constant across species plots. Temperature and precipitation values were often negatively associated with first visit values (cooler and wetter plots disproportionately warmed and dried). Maximum and minimum VPD generally increased most at plots with initially higher VPD values. These results indicate that the geographical range of U.S. west coast tree species may not change as quickly as their ecological niches geographically shift, although changes in species densities within their ranges may already be underway. The results also indicate that changes in environmental conditions may differ among and within species’ ranges.