Climate warming can cause arthropods to express plastic and/or evolved changes in morphology. Previous studies have demonstrated that body sizes of Arctic butterflies are influenced by the temperatures experienced as larvae. To investigate whether this was occurring among Alaskan butterflies, we analyzed temporal trends in the wing sizes of three Holarctic species, Colias hecla, Boloria chariclea, and Boloria freija, using museum specimens collected in Arctic tundra regions of Alaska between 1971 and 1995. Wing length was compared to accumulated growing degree days (GDD) during both the spring of the year collected and the previous year’s summer during the normal period of larval development. We used mixed-effects models to test if spring and summer temperatures affected adult morphology. Results show that for every 1°C increase in average seasonal temperature, wingspans decreased between 0.7 millimeters and 5 millimeters, with B. freija the most strongly affected. Our results suggest that the morphological sensitivity of Arctic butterflies to warming is the outcome of interactions between life-history traits and regional climate, with all species sensitive to warming the summer before the flight year as well as warming the spring of the flight year. B. freija, which overwinters as late instar larvae that do not feed before pupation the following spring, was particularly strongly affected by summer warming.

Large-scale spatial patterns of species richness are one of the central issues in ecology. Although hypotheses based on effects of contemporary climate, evolutionary history and historical climate change have been employed to explain the mechanisms underlying species richness patterns, variation in relative contribution of different hypothesis remains a major challenge. Here, using newly-compiled distribution data with a spatial resolution of 100 * 100 km2 for 43,023 seed plant species in eastern Eurasia, we mapped species richness patterns for plants with different growth forms (i.e., woody vs. herbaceous) and range sizes (i.e., wide-ranged vs. narrow-ranged species), and compared the contribution of four hypotheses on these patterns, i.e., freezing tolerance hypothesis, historical climate change hypothesis, Janzen hypothesis and diversification rate hypothesis. We found that species richness of all seed plants presented a clear latitudinal gradient and was the highest in southwestern China and Central Asian mountains. Notably, species richness patterns and their dominant hypotheses differed between species groups. Historical climate change dominated richness patterns of overall, herbaceous and wide-ranged herbaceous species. The freezing tolerance hypothesis dominated those for all woody and wide-ranged woody species, while the Janzen hypothesis dominated narrow-ranged woody and herbaceous species. Our study suggests that different hypotheses contribute to large-scale species richness patterns via their dominant effects in different species groups. Interestingly, our study did not support the diversification rate hypothesis, but demonstrated high contribution of historical climate change to plant diversity, providing new perspectives on the mechanisms of plant diversity patterns in eastern Eurasia.

Long-term studies of cyclic rodent populations have contributed fundamentally to the development of population ecology. Previous research has shown macroecological patterns of population dynamics in relation to latitude, but without disentangling the role of underlying ecological and climate drivers. We collected 26 rodent time-series from the tundra biome and assessed how population dynamics characteristics of the most prevalent species varied with latitude and environmental variables. While we could not find a relationship between latitude and population cycle peak interval, other characteristics of population dynamics had latitudinal patterns. The environmental predictor variables provided insight into causes of these patterns, as i) increased proportion of optimal habitat in the landscape led to higher population cycle amplitudes in all species and ii) mid-winter climate variability had negative impacts on cycle amplitude in Norwegian lemmings and grey-sided voles. These results indicate that biome-scale climate and landscape change can be expected to have profound impacts on rodent population cycles and that the macro-ecology of such functionally important tundra ecosystem characteristics is likely to be subjected to transient dynamics.

Aim: We aimed to assess the impact at the global level of physical anthropogenic disturbances on the dominant mycorrhizal types in ecosystems and how this mechanism can potentially lead to lasting plant community changes. Location: Globally distributed study regions Time Period: 2007-2018 Taxa studied: Plants and mycorrhizal fungi Methods: We used a database of coordinated plant community surveys following mountain roads from 894 plots in 11 mountain regions across the globe in combination with a database of mycorrhizal-plant associations in order to estimate the relative abundance of mycorrhizal types in natural and disturbed environments. Results: Our findings show that roadside disturbance promotes the cover of plants associated with arbuscular mycorrhizal (AM) fungi. This effect is especially strong in colder mountain environments and in mountain regions where plant communities are dominated by ectomycorrhizal (EcM) or ericoid-mycorrhizal (ErM) associations. Furthermore, non-native plant species, which we confirmed to be mostly AM plants, are more successful in environments dominated by AM associations. Main Conclusions: These biogeographical patterns suggest that changes in mycorrhizal types are a crucial factor in the worldwide impact of anthropogenic disturbances on mountain ecosystems by promoting AM-dominated systems and potentially weakening biotic resistance against non-native species invasion. Restoration efforts in mountain ecosystems will have to contend with changes in the fundamental make-up of EcM- and ErM plant communities induced by roadside disturbance.

Our goal was to interrogate Janzen’s idea that “mountain passes are higher in the tropics” by investigating putative ecological and biogeographic drivers of patterns of elevational range-sizes among equatorial plant families. We used herbarium records for sixty species-rich plant families, representing a total of 18535 species, to estimate distributions over a 4500 m elevational gradient. For each family, we estimated the change in average range-sizes with increasing elevation (i.e. Rapoport’s rule, abbreviated as ERR) and quantified 15 metrics of familial richness distribution, evolutionary age, and biogeographic affiliation. We visualized covariation across families using used phylogenetic principal components analysis (pPCA), with color illustrating endemism. We then evaluated how family-level ERR slopes correlated with each metric individually, and the first two pPCA components, using phylogenetic independent contrasts. Families with greater Sundaland endemism, or richness that was restricted to tropical lowland forests, had positive ERR slopes. Families with stronger Sahul affiliation, or montane centered richness, had shallower, neutral, or negative ERR slopes. Families with Wallacea affiliation, broader latitudinal or elevational distributions, cosmopolitanism, or older evolutionary age had mixed results. Our findings support Janzen’s hypothesis that “mountain passes are higher in the tropics.” If long term climate stability over millions of years promotes habitat specialization, then among taxa with long-term tropical affiliations, we would expect smaller range-sizes within lowland forests, with range-size expansion towards higher elevations, expressed as a positive ERR slope. Conversely, variation in growing conditions should promote larger, relatively consistent, range-sizes expressed as a neutral ERR slope. Our results support this corollary because of the dichotomy of ERR slopes observed in relation to elevational and historical biogeographic positioning, which may be an indicator of vulnerability of these plant groups to contemporary climate change.

The three-dimensional rarity typology proposed by Rabinowitz in 1981, based on geographic range, habitat specificity, and local abundance, is among the most widely used frameworks for describing rarity in ecological and conservation research. While this framework is descriptive and is not meant to explain the causes of rarity, recent advances in ecology may be leveraged to add explanatory power. We propose a modification of Rabinowitz’s typology to better distinguish between the dimensions of rarity and the ecological processes that drive them, and explore the conservation implications of our modified framework. We suggest replacing habitat specificity with occupancy (the proportion of occupied sites within a species’ range), yielding a modified classification based on range size, occupancy, and local abundance. Habitat specificity remains embedded in our framework, but as a driver of rarity rather than a rarity axis. Under our framework, habitat specialists are no longer considered rare if they are widespread and abundant; we argue that this modification more accurately identifies truly rare species, as habitat specialists may be common if their habitat is abundant. Finally, we draw on the functional and theoretical literature to identify the key processes and associated traits that drive each rarity axis. In this respect, we identify four processes (environmental filtering, movement, demography, and interactions), and hypothesise that range size and occupancy are primarily driven by environmental filtering and movement, whereas local abundance is more strongly influenced by demography and interactions. We further use ecological theory to hypothesise the conservation concerns associated with each rarity axis, and propose conservation measures that may be suitable for conserving different types of rare species. Our work may provide a basis for developing hypotheses about the causes of rarity of particular focal taxa or groups, and inform the development of targeted conservation strategies.

1. Alpine plants possess unique traits owing to their adaptation to alpine environments. However, it remains unknown whether leaf trait relationships of alpine plants can be captured by the two general trait dimensions of organ size and resource economics. 2. We hypothesized that, beyond the trait dimensions of leaf size and resource economics, non-structured carbohydrates (NSCs) would reflect an important dimension of cold-tolerance in alpine plants. 3. We measured 12 leaf traits critical to leaf construction, growth, and stress resistance in 225 site species, ranging from 7 sites along the alpine steppes to alpine meadows on the Tibetan Plateau. We also examined the cold-tolerance of 11 species at one of these sites by estimating the lethal temperature causing 50% frost damage (LT50). We investigated the variation and potential leaf trait dimensions of alpine plants and verified whether the third leaf trait dimension is related to cold-tolerance by analyzing the relationships of NSCs and LT50. 4. The majority of variations in 12 leaf traits of alpine plants were captured by three trait axes, in which leaf carbon (LCC) and NSCs (including starch, LSC and soluble sugars, LSS) were clustered in a new dimension (PC3) beyond leaf size and structure, and resource economics. Although LCC, LSC and LSS all showed negative correlations with MAT, a significant negative correlation was only found between LSS and LT50. It indicated that PC3 was able to reflect the cold-tolerance of alpine plants to some extent, in which LSS was the most critical trait. 5. Thus, the storage and transformation of NSCs under stressful conditions could reflect a dimension of long-term metabolic adaptation and cold-tolerance, which is an extension of the resource-utilization strategy beyond construction cost and growth. Our study suggested that NSCs should not be ignored in leaf economic spectrum for alpine plants.

Few studies have evaluated the relative importance of various factors in the invasion process of exotic plants in freshwater ecosystems due to the difficulty of observing numerous factors simultaneously. In this study, to explore how various biotic and abiotic factors determine the overall invasion extent of all exotic plants and the invasion extent of different life-form exotic plants as well as assess their relative importance, we surveyed 236 exotic aquatic plant communities using 2267 fine quadrats in China's freshwater ecosystems. We found that competition from native plants was the most vital factor determining the mean biomass of all exotic plants and biomass of submerged plant Cabomba caroliniana, while competition from co-occurring exotics was the most important for biomass of emergent plant Alternanthera philoxeroides and free-floating plant Eichhornia crassipes. The population biomass of different exotic species responded differently to climate change. Water eutrophication could accelerate the invasion of exotic plants by directly favoring them and indirectly weakening the resistance of native plants. Water depth, habitat size, herbivory, and anthropogenic disturbance had relatively weak impacts on the biomass of exotic plants. Moreover, some factors have different modes of influence on different exotic plants. Our study suggested interspecific competition plays a more important role in the population spread of exotic plants than climate and abiotic environment once the plants have successfully established, implying that biodiversity conservation and vegetation restoration were the fundamental methods to control invasion. In addition, our study highlights the importance of studying the overall invasion extent of all exotic plants and interactions among invaders in multi-invader communities.

Alien species can have massive impacts on native biodiversity and ecosystem functioning. Assessing which species from currently cultivated alien floras may escape into the wild and naturalize is hence essential for ecosystem management and biodiversity conservation. Climate change has promoted the naturalization of many alien plants in temperate regions, but whether outcomes are similar in (sub)tropical areas is insufficiently known. In this study, we used species distribution models to evaluate the current naturalization risk of 1,527 cultivated alien plants in 10 countries of Southern Africa and how their invasion risk might change due to climate change. We assessed changes in climatic suitability across the different biomes of Southern Africa. Moreover, we assessed whether climatic suitability for cultivated alien plants varied with their naturalization status and native origin. The results of our study indicate that a significant proportion (53.9%) of the species are projected to lack suitable climatic conditions in Southern Africa, both currently and in the future. Based on the current climate conditions, 10.0% of Southern Africa is identified as an invasion hotspot (here defined as the top 10% of grid cells that provide suitable climatic conditions to the highest numbers of species). This percentage is expected to decrease slightly to 7.1% under moderate future climate change and shrink considerably to 2.0% under the worst-case scenario. This decline in climatic suitability is observed across most native origins, particularly under the worst-case climate change scenario. Our findings indicate that climate change is likely to have an opposing effect on the naturalization of currently cultivated average plants in (sub)tropical Southern Africa compared to colder regions. Specifically, the risk of these plants’ naturalizing is expected to decrease due to the region’s increasingly hot and dry climate, which will be challenging for the persistence of both native and alien plant species.

A quarter century after the 1998 El Niño, it is still difficult to predict how individual reefs will respond to recurring disturbances. Reports differ on the relative importance of anthropogenic influences, local geography and bleaching recurrence in determining resistance and recovery. It is assumed that coral traits largely determine winners and losers, based on bleaching susceptibility, recruitment, survival and growth. Whether this translates to the long-term fates of corals on reefs is still debated. We tracked multi-decadal coral compositional changes in reefs across the densely populated Lakshadweep Archipelago to explore how global bleaching events and local geographical factors (depth and wave exposure) influenced responses to repeated mass bleaching. Coral resistance increased with recurrent bleaching, uninfluenced by local geography. However, wave exposure regimes positively influenced recovery rates, given sufficient time between mortality events (>7 years). The overall trajectory though, was of protracted decline interspersed with periods of halting recovery, with many losers, and few resistant genera that lose less. Based on these responses, we identified six community clusters that describe contrasting long-term responses to local and global factors. Interestingly, genera with different functional traits cluster together, sharing similar fates, as a result of complex interactions between bleaching susceptibility, local geography and inter-bleaching intervals. These clusters provide a clear site-specific predictive framework of long-term community change, indicating that geography, community and time largely determine local responses to climate disturbances.

Montane species are generally predicted to respond to climate change via upslope movement. In birds, these potential elevational range shifts have primarily been examined in tropical regions. Although desert bird species may be at the edge of their aridity tolerances, elevational range shifts of desert bird species rarely have been studied. Here, we examine shifts in the elevational distributions of breeding birds from two regions of the Great Basin, a desert in the western United States, over 10 to 20 years. We collected data annually from 2001-2020, a relatively long time series that is uncommon in research on distributional shifts. We used single-species occupancy models of 32 bird species to examine elevational shifts at three extents: the full elevational gradient (1650-3200 m) and the lowest and highest edges (25%) of the gradient. We then conducted simulations to test whether population stochasticity could confound inferences about shifts. We examined whether temperature, precipitation, and primary productivity (normalized difference vegetation index) were associated with occupancy and shifts. The elevational distributions of 19 species shifted, and simulations indicated that shifts in the distributions of 12 species were unlikely to be stochastic. The three shifts along the full elevational gradient were downslope, and the majority of distributional shifts occurred at the elevational range edges. Occupancy of 10 species with elevational distributions that shifted was associated significantly with precipitation, and 8 of those associations were negative. Although we found that climate changed considerably even over the short temporal extent of our study, our results suggested that this community of desert birds is relatively resilient to the direct effects of climate change.

Thermal adaptation of organisms is a property emerging from the complex interplay of biophysical constraints and selective forces. The shape of thermal performance curves has been well investigated but we lack knowledge of how they may evolve. Two extreme cases can be expected: i) under the hypothesis of local adaptation, species should shift their thermal performance curves and have an optimum at the temperature at which they evolve, or ii) under the hypothesis of thermodynamical constraints, universal biophysical rules dictate a fixed performance curve with an optimum at warm temperatures. We perform an evolutionary experiment to test these two hypotheses on the thermal response of bacteria growth rate, expecting a strong evolutionary response of the thermal performance curve. We use four wild bacterial strains and allow them to evolve at ten different temperatures (ranging from 8.5 to 40°C) to subsequently measure their growth rate at these ten temperatures. We investigate the difference in growth rate between evolved lines and their ancestors. We observe signs of adaptation, as growth rates of evolved and ancestral strains exhibit small but significant differences. Our analysis shows however that the shape of the thermal performance curves does not systematically vary between evolved and ancestral strains, and none of the evolved lines have an optimal growth rate at the evolution temperature. One strain grows significantly faster than its ancestor at the temperature of evolution, but we find that for other strains, evolution leads to faster as well as slower growth rates. These differences are repeated between evolutionary replicates, suggesting they are selected. Our study demonstrates that adaptation does not always overcome thermodynamical constraints on growth rates, and helps to better understand how microbes will respond to temperature changes.

Marine ice is retreating in many sectors of Earth’s polar and subpolar regions. The rates are unprecedented, generating great concern in both scientific and public communities. Despite the expected serious implications, we lack a comprehensive understanding of how ice loss and related processes control marine biota and interactions at different spatiotemporal scales under multiple environmental stressors and drivers of change. We systematically review existing knowledge on how the losses of ice shelves, sea ice, and glaciers affect polar marine biocenosis. We include in situ, remote sensing, and modelling studies on sea ice biota, phyto- and zooplankton, fish, seabirds, phyto- and zoobenthos and marine mammals, covering a time span of three decades (1991-2022). We apply a qualitative ecosystem‐based risk assessment to assess the individual and cumulative response of ecosystem components and related ecosystem services. The most threats and opportunities are expected to manifest in the shallow coastal zones. They include loss of ice habitat, water column darkening due to sediment input with meltwater, increased sedimentation rates, and mechanical damage due to ice scouring, but also gain of marine habitat, lightening of the water column and nutrient input with meltwater. The cumulative score of all the stressors shows that marine ice loss will lead to autotroph-dominated polar marine systems with detrimental effects on secondary producers, i.e. zooplankton and zoobenthos, and sea ice-obligate species. Although similar stressors are recognised for polar and subpolar regions, some processes may differ in magnitude. This overview aims to provide summarised knowledge to inform science-based solutions for conservation and climate mitigation actions.