Integrated distribution models (IDMs), in which datasets with different properties are analysed together, are becoming widely used to model species distributions and abundance in space and time. To date, the IDM literature has focused on technical and statistical issues, such as the precision of parameter estimates and mitigation of biases arising from unstructured data sources. However, IDMs have an unrealised potential to estimate ecological properties that could not be derived from the source datasets if analysed separately. We present a model that estimates community alpha diversity metrics by integrating one species-level dataset of presence-absence records with a co-located dataset of group-level counts (i.e. lacking information about species identity). We illustrate the ability of IDMs to capture the true community alpha diversity through simulation studies and apply the model to data from the UK Pollinator Monitoring Scheme, to describe spatial variation in the diversity of solitary bees, bumblebees and hoverflies. The simulation and case studies showed that the proposed IDM produced more precise estimates of the community diversity than the single models, and the analysis of the real dataset further showed that the alpha diversity estimates from the IDM were averages of the single models. Our findings also revealed that IDMs had a higher prediction accuracy for all the insect groups in most cases, with this performance linked to the information provided by a data source into the IDM.

Forests provide essential ecosystem services that range from the production of timber to the mitigation of natural hazards. Rapid environmental changes, such as climate warming or the intensification of disturbance regimes, threaten forests and endanger forest ecosystem services. In light of these challenges, it is essential to understand forests’ demographic processes of regeneration, growth, and mortality and their relationship with environmental conditions. Specifically, understanding the regeneration process in present-day forests is crucial since it lays the foundation for the structure of future forests and their tree species composition. We used Swiss National Forest Inventory (NFI) data covering vast bio-geographic gradients over four decades to achieve this understanding. Trees that reached a diameter at breast height of 12 cm between two consecutive NFI campaigns were used to determine regeneration and were referred to as ingrowth. Employing three independent statistical models, we investigated the number, species, and diameter of these ingrowth trees. The models were subsequently implemented into a forest simulator to project the development of Swiss forests until the mid-21st century. The simulation results showed a decrease and a shift in the species composition of ingrowth, marked by a significant decrease in Norway spruce (Picea abies) and concurrent increases in broadleaves. Nevertheless, the pace of this change towards a more natural species composition is relatively slow and is likely to slow down even further as ingrowth declines in the future, in contrast to the fast-changing climatic conditions. Hence, support through adaptive planting strategies should be tested in case ingrowth does not ensure the resilience of forests in the future. We conclude that since the regeneration of forests is becoming increasingly challenging, the current level at which ecosystem services are provided might not be ensured in the coming decades.

Anthropogenic climate change is creating a more flammable future by increasing the number of days when vegetation is dry enough to burn. Indices representing the percent moisture content of dead fine fuels as derived from meteorological data have been used to assess geographic patterns and temporal trends in vegetation flammability. To date, this approach has assumed a single flammability threshold, typically between 8 and 12%, controlling fire potential regardless of the vegetation type or climate domain. Here we investigate geographic variation in fuel moisture levels associated with observed fire activity among ecoregions by analysing global reanalysis data and remotely sensed burnt area products. This geospatial analysis identified a wide range of ecoregion flammability thresholds (EFTs) associated with fire activity, often well above or below the commonly used range of values. Many boreal and temperate forests, for example, can burn with much higher fuel moisture than previously identified; Mediterranean forests, on the other hand, tend to burn with consistently low fuel moisture. Bayesian modelling showed that EFTs are primarily driven by eco-climatological variables, particularly precipitation and temperature. Our analysis also identified complex associations between vegetation structure, fuel types, and climatic conditions highlighting the complexity in vegetation-climate-fire relationships globally. Our study provides a critical, necessary step in understanding and describing global pyrogeography and tracking changes in spatiotemporal fire activity.

The present distribution of Siberian boreal forests that are dominated by larches is influenced, to an unknown extent, by the glacial history. Knowing the past treeline response to climate shifts can improve our understanding of future treeline dynamics under changing climate. Here, we study patterns in the genetic variability of Siberian larches (Larix spp.) that can help us to unravel biogeographic migration routes since the Last Glacial Maximum (LGM). We sampled 148 larch individuals from Eastern Siberia. For each individual, genome-wide single nucleotide polymorphisms (SNPs) were derived through genotyping by sequencing (GBS). We inferred the spatial distribution from 14,003 SNPs with a cluster analysis. To infer the postglacial demographic history of Larix, we applied an Approximate Bayesian Computation. The Bayesian population assignment statistically supported three to four clusters from Western to Eastern Siberia that correspond well to the geographic ranges of the main Siberian larch species Larix sibirica, L. gmelinii, and L. cajanderi. Using four plausible clusters, the tested hypotheses in DIYABC show that the existing populations seem to have been initiated long before the LGM. We presume that the different populations originate from larch populations that survived the glacial periods. From our genetic studies, we deduce that Larix was more likely to have survived the cold LGM in northern refugia, from where a fast colonization of Siberia was possible, rather than Larix completely repopulating Siberia in the postglacial spreading out from southern areas with less harsh climatic conditions. The northernmost expansion during the Holocene seems to have benefitted from refugial populations ahead of the treeline at that time, which explains the existence of Larix in the far north. We expect from our results that the present migration will be slow at first as there are currently no refugial populations far north, as there probably were in the Holocene.

Soil microbes play a key role in shaping terrestrial ecosystems. It is therefore essential to understand what drives their distributions. While multivariate analyses have been used to characterise microbial communities and drivers of their spatial patterns, few studies focused on modelling the distribution of Operational Taxonomic Units (OTUs). Here, we evaluate the potential of species distribution models (SDMs), to predict the presence-absence and relative abundance distribution of bacteria, archaea, fungi and protist OTUs from the Swiss Alps. Advanced automated selection of abiotic covariates was used to circumvent the lack of knowledge on the ecology of each OTU. ‘Presence-absence’ SDMs were successfully applied to most OTUs, yielding better predictions than null models. ‘Relative-abundance’ SDMs were less successful, yet, they were able to correctly rank sites according to their relative abundance values. Archaea and bacteria SDMs displayed better predictive power than fungi and protist ones, indicating a closer link of the latter with the abiotic covariates used. Microorganism distributions were mostly related to edaphic covariates. In particular, pH was the most selected covariate across models. The study shows the potential of using SDM frameworks to predict the distribution of OTUs obtained from environmental DNA (eDNA) data. It underscores the importance of edaphic covariates and the need for further development of precise edaphic mapping and scenario modelling to enhance prediction of microorganism distributions in the future.

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.

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.

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.

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.