Climate Change Ecology最新文献

Climate change presents a major threat to biodiversity globally. Northern ecosystems, such as Canada's boreal forest, are predicted to experience particularly severe climate-induced changes. These changes may reduce the carrying capacity and habitat suitability of the boreal forest for many wildlife species. Boreal birds are susceptible to both direct and indirect effects of climate change, and several studies have predicted northward shifts in species distributions as temperatures become warmer. We forecasted spatially-explicit changes in the densities of 72 boreal landbird species using integrated climate change projections and a forest dynamics model in the Taiga Plains ecozone of the Northwest Territories (NT), Canada, over the 2011–2091 horizon. We 1) identified "winner," "loser," and "bellringer" species over short (2031) and long-term (2091) forecasts, 2) mapped landbird range and density changes under three contrasting Global Circulation Models (GCMs), and 3) quantify differences in landbird density predictions across a latitudinal gradient. Species that showed a moderate increase or decrease in their predicted abundance were considered "winners" and "losers," respectively. Species that showed a marked increase or decrease – a doubling or halving – of their predicted abundance in all three GCMs, were termed "bellringers". From 2011–2031, only 2/72 (2.8%) were considered winners, and 3/72 (4.2%) were losers. From 2011–2091, the abundance of more species was predicted to change: 26/72 (36.1%) were winners, and 10/72 species (13.9%) were losers. Four species were considered bellringers: Gray-cheeked Thrush, White-crowned Sparrow, Fox Sparrow, and American Tree Sparrow. Overall, projected range shifts were strongly oriented along a southeast-to-northwest axis. Shifts to the north and south were evenly distributed among all three GCMs. Our results suggest that future climate-mitigated distribution shifts and population declines of boreal landbirds will require targeted conservation actions. They also highlight the importance of the NT as a potential refugium for many boreal-breeding landbird species in Canada.

Desert regions are becoming both warmer and more arid, potentially challenging the ability of even arid-adapted species to exist within their current ranges. Here we analyzed the sensitivity of the common chuckwalla, Sauromalus ater, a vegetarian lizard restricted to western North America's warm deserts, to predicted increases in temperature and aridity. We also assessed the response by their primary food plants to these changing conditions. Our study area included both east-west and elevational aridity gradients. At the eastern, most arid end of this gradient the highest population densities of chuckwallas were restricted to the top elevation category, 600-699 m. In the middle of the east-west gradient, higher chuckwalla densities occurred at elevation categories of 400-599 m and above. At the western, least arid end of the gradient, high chuckwalla densities occurred from elevation categories beginning at 200 m. Their food plants mirrored that distribution trend. We also constructed independent habitat models to predict current and future suitable ranges for both the lizards and their food plants. Potential climate refugia exist where modeled current and predicted future ranges overlap. Our empirical elevation data for where chuckwallas and their food plants exist at higher densities mirrored the climate refugia predicted by our models; current higher density populations largely already reside in putative climate refugia. Chuckwallas residing below these refugia will find conditions increasingly challenging, and all populations will need to shift to higher elevations if future levels of aridity exceed the values used in our models.

Climate change may induce mismatches between wildlife reproductive phenology and temporal occurrence of resources necessary for reproductive success. Verifying and elucidating the causal mechanisms behind potential mismatches requires large-scale, longer-duration data. We used eastern wild turkey (Meleagris gallopavo silvestris) nesting data collected across the southeastern U.S. over eight years to investigate potential climatic drivers of variation in nest initiation dates. We investigated climactic relationships with two datasets, one inclusive of successful and unsuccessful nests (full dataset) and another of just successful nests (successfully hatched dataset), to determine whether successfully hatched nests responded differently to weather changes than all nests did. In the full dataset, each 10 cm increase in January precipitation was associated with nesting occurring 0.46–0.66 days earlier, and each 10 cm increase in precipitation during the 30 days preceding nesting was associated with nesting occurring 0.17–0.21 days later. In the successfully hatched dataset, a 10 cm increase in March precipitation was associated with nesting occurring 0.67–0.74 days earlier, and an increase of one unit of variation in February maximum temperature was associated with nesting occurring 0.02 days later. We combined the results of these modeled relationships with multiple climate scenarios to understand potential implications of future climate change on wild turkey nesting phenology; results indicated that mean nest initiation date is projected to change by <0.1 day by 2040–2060. Wild turkey nesting phenology did not track changes in spring green-up timing, which could result in phenological mismatch between the timing of nesting and the availability of resources critical for successful reproduction.

Migratory bird trajectories are the result of their own speed and direction in combination with wind speed and direction. Several studies have focused on the interplay between bird migration and general wind patterns, however, the majority of them did not take into account climate change and used a small number of individuals. By integrating tracking data from two populations of Arctic terns (n = 72) with ERA5 and Earth System Model (ESM) wind data, we were able to study the current conditions and the potential effects of climate change on them.

The Svalbard birds experienced wind support values around 3 m/s with a relatively low variability, while the Dutch population experienced almost no wind support with a greater variability. Svalbard terns exhibited better adjustment of their flyways to daily and annually varying wind conditions, and responded to crosswinds by drifting over extended periods/regions (median Drift Ratio ± standard deviation: 0.51 ± 0.18) while the Dutch population mostly compensated (0 ± 0.31). We suggest that the Svalbard birds will be able to adapt their flyways to future Atlantic Ocean wind pattern changes, while we are uncertain whether the Dutch population can keep compensating for future changes or not.

We examine the robustness of our results by using a selection of ESMs and by including metrics for several uncertainty sources (ESMs, wind variability, tracking method etc.). This study highlights the importance of wind as a flyway-shaping factor and points out the possibility for different responses to wind by different populations of the same species, in different Ocean regions and seasons.

Climate forecasts suggest the Great Plains of North America have increased risk of droughts during global warming. Environmental factors have potential to influence turtle populations in aquatic habitats through temperature-dependent sex determination and influences on food availability. Long-term studies are critical to evaluate the influence of climatic variation on turtles. We used a 12-year set of mark-recapture data collected from painted turtles (Chrysemys picta, n = 162) in a pond in Keith County, Nebraska during 2005–2016 to assess variation in sex ratio and growth dynamics. Southwest Nebraska experienced two periods of drought during our study (Palmer Hydrologic Drought Index [PHDI] range: -4.5 to 6.7). Despite a relatively stable depth of water in our study pond, the proportion of males in the second size class (carapace length 95–130 mm) decreased when the PHDI during their incubation period indicated hotter, drier conditions. Discrete, mean annual growth (G) of females >30 mm below asymptotic carapace length was greater during wetter years (G_non-drought = 15.0, G_drought = 11.5), and a drought coefficient (D) in our modified von Bertalanffy model reflected reduced growth of both males (D = -0.0226) and females (D = -0.0393) during drought years. Our long-term research provides context to the complexity by which turtle species may respond to changes in long-term climate conditions.

In many rural East African areas, anti-malarial plants are commonly used as first-line treatment against malaria. However, spatially explicit information about the future availability of anti-malarial plant species and its relation to future suitable habitat for malaria vectors is limited. In this study we 1) model the distribution of anti-malarial plant and malaria vector species and assess the drivers of their distributions taking the example of the Samburu dryland in Kenya, 2) map the modeled overlap in this area, 3) assess the impact of future climate change on anti-malarial plant and malaria vector species and 4) report their future overlaps. Our results show that mean temperature of warmest quarter, precipitation of wettest quarter and mean temperature of coldest quarter were the most important environmental variables that affected the distribution of anti-malarial species. The effects of climate change will be detrimental, since most areas will witness huge losses in anti-malarial species habitat while only a few gained or remained stable under both SSP2-4.5 and SSP5-8.5 climate change scenarios by 2050s and 2070s. According to most of our scenarios, more than half of the anti-malarial species will become threatened by 2050s and 2070s. A comparison between distribution patterns of future anti-malarial species richness and malaria vector species suitable habitat suggests that the former will decrease considerably while the later will increase. Because the availability of anti-malarial species will decrease in the areas affected by malaria vectors, geographically targeted conservation strategies and further control measures against malaria vectors are all the more important.

The joint effects of climate change and landscape fragmentation to the genetic viability of isolated populations has barely been addressed for the Atlantic Forest fauna. Therefore, this work explored the potential habitat suitability for the southern muriqui (Brachyteles arachnoides), by modeling climate change, landscape fragmentation, and genetic diversity loss of the species. Maxent was used to model its potential distribution in 2050, with two climate change scenarios. A land use and land cover change model was applied to describe current and future forest fragmentation patterns, and a Population and Habitat Viability Analysis (PHVA) was used to describe the retention of genetic diversity of the southern muriqui. Although PHVA modeling provided a low risk of extinction of the southern muriqui, climate change and fragmentation could result in the loss of >65% of the suitable forest patches, and reduce the habitat suitability to only 11% of the potential distribution area, which could lead to future genetic diversity loss and decreased capacity of self-sustained populations. In both climate change scenarios, the suitable areas for the southern muriqui in Paraná and Rio de Janeiro states will decrease more drastically. Areas where the primate occurs in the interior of São Paulo and Rio de Janeiro states will disappear or be climatically disconnected from the core potential habitat. Alike preventing further deforestation, Atlantic Forest restoration actions are needed to connect the viable populations for compensating the projected land use and climate change impacts to the long term persistence of the southern muriqui.

Global change has the potential to affect organisms and re-structure ecosystems where key species interactions, such as herbivory, are disrupted. The fastest ways individual herbivores – and therefore ecosystems – can respond to climate change is through shifts in behaviour. In marine habitats, environmental changes of particular concern in the future are ocean acidification and warming. Consequently, we reviewed the existing literature in this area of research, to identify if there were any over-arching trends or emerging patterns in behavioural responses of marine herbivores to ocean acidification and warming. We identified that while the body of research is growing, focus remains primarily on few locations (temperate areas), phyla (Mollusca, especially gastropods; Crustacea; Echinodermata), and behaviours (grazing rate, movement). Although representing a relatively narrow view of future herbivory, this review indicates that in many cases, the key behaviours of feeding and movement could be maintained under ocean acidification and warming. However, where change is observed, it is more likely grazing will be enhanced and movement impaired. If such patterns were to manifest under future climates, it would mean that the herbivores present would consume more yet there may be less of them as impaired movement and escape behaviours would have made them more vulnerable to predation. The exact responses will, however, likely be context-dependant. Therefore, we recommend future studies address the research gaps our review identified (i.e., a lack of understanding in tropical and polar regions, economically and ecologically important Crustacean and Echinoderm species, early life history stages, and more behavioural responses in addition to feeding and movement). Understanding the diversity of responses expected under varied contexts will be important to uncover trends in how marine invertebrates will behave under global change.

The role of physiology on habitat specialization in terrestrial ectotherms constitutes a rarely addressed topic, despite the fact that habitat specialization often involves the coadaptation of multiple physiological traits, which in turn may confer a higher vulnerability to climate change. Here we documented aspects of the thermal and hydric physiology of Sceloporus macdougalli, a lizard restricted to granite boulders in a tiny area of a tropical dry forest of Mexico, and estimated its vulnerability to climate change. We aimed to determine the physiological and behavioral adjustments used by this species to cope with a striking seasonal environment, to elucidate whether ecophysiology could help explain its habitat specialization, microendemicity, and how increasing environmental temperatures will restrict activity of this species. The effectiveness of thermoregulation and indications of water conservation strategies changed markedly over seasons. As expected, granite boulders and associated vegetation were more suitable for thermo- and hydroregulation than surrounding (and unoccupied) habitat. However, our model indicated that by 2041-2060 climate change will restrict activity of this species, enhancing its threat of extinction. These results highlight the importance of granite microhabitats for the thermal and water relations of S. macdougalli, in the context of climate change, and suggest that the current habitat and range restriction of the species might be an outcome of its physiology, thus demanding urgent actions to preserve the species from extinction.