Climate Space Research Articles

Plant growth forms dictate adaptations to the local climate.

Adaptive radiation is a significant driver of biodiversity. Primarily studied in animal systems, mechanisms that trigger adaptive radiations remain poorly understood in plants. A frequently claimed indicator of adaptive radiation in plants is growth form diversity when tied to the occupation of different habitats. However, it remains obscure whether morphological adaptations manifest as growth form diversity per se or as its constituent traits. We use the classic Aeonium radiation from the Canary Islands to ask whether adaptation across climatic space is structured by growth form evolution. Using morphological sampling with site-associated climate in a phylogenetic context, we find that growth forms dictate adaptations to the local environment. Furthermore, we demonstrate that the response of specific traits to analogous environments is antagonistic when growth forms are different. This finding suggests for the first time that growth forms represent particular ecological functions, allowing the co-occurrence of closely related species, being a product of divergent selection during evolution in sympatry.

Limited dispersal ability and restricted niche characterize “depauperons” in Melastomataceae

The asymmetric pattern in species richness is a notable feature across different lineages and geographic regions. While some lineages have high richness, diversity and wide distribution, others have the opposite. Despite low rates of diversification, the latter might also be phylogenetically isolated. Lineages that accumulate these characteristics are known as “depauperons'' and explaining their existence and persistence through time is still a challenge. The plant family Melastomataceae contains both megadiverse lineages (such as the tribe Miconieae, with around 1900 species) and groups with few species (such as the tribes Eriocnemeae, Lithobieae, and Rupestreeae with 7, 1 and 2 species, respectively). These three clades are restricted to eastern Brazil, where they have been seldom studied. The lack of information about their basic biology as well as which processes determine their distribution have not been previously studied. Here we integrated metrics of dispersal ability, species distribution models (SDMs) and natural history data compilation in order to uncover common patterns shared by these depauperons in Melastomataceae and raise conservation concerns. For all nine species we estimated the dispersal ability and generated SDMs in different time-periods (past, present and future). Dispersal ability was associated with predicted distribution models under future scenarios to evaluate shifts and/or retractions in suitable areas. In addition, we compared the climatic tolerances of the depauperons with their megadiverse sister tribes via climatic envelopes. Overall, our results indicate limited dispersal ability, dependency on water for dispersal, and restricted niche as common characteristics for all species in the deupauperon tribes Eriocnemeae, Lithobieae and Rupestreeae. Our analyses also show that the climatic niche spaces of the depauperons are limited and totally included within the niche space of its sister tribes. Based on our findings, the level of threat in these groups can be potentiated by rapid climate change, mainly due to their inability to spread over long distances, restricted niches and increased habitat fragmentation. We suggest that future conservational actions prioritize these unique taxa in Melastomataceae, especially if a phylogenetic diversity perspective is taken into account.

Protected area network insufficiently represents climatic niches of endemic plants in a Global Biodiversity Hotspot

Protected Areas (PA) play a pivotal role in conservation biology. Climate change challenges the concept of static PAs as species may not find suitable climatic conditions in the PAs designed to protect them in the future. Here, we assess this emerging mismatch for the endemic mountain flora of the Iranian Plateau, the main part of the Irano-Anatolian global biodiversity hotspot. We compare the climatic requirements of each of 1277 endemic plant species with the climatic conditions offered by those parts of the Iranian PA network that are within the dispersal range of each species. We undertake this comparison for current climatic conditions and the conditions predicted for the years 2050 and 2070 under the climatic scenarios RCP4.5 und RCP8.5. We find that 50 % of the species climatic niche space is represented in the PA network under current conditions. Depending on the climatic scenario and time frame, representation will decrease to 15–25 % in the future. Species of lowest and highest elevations, and, in particular, species with narrow ranges, are predicted to face the most pronounced losses of climatic representation in PAs. We conclude that the contribution of the current Iranian PA network to protecting the rich endemic flora of the country under climate change is limited. The network overrepresents climatically homogenous desert ecosystems and neglects endemism hotspots of high mountain chains. Efficient conservation planning in this biodiversity hotspot should focus on expanding elevational gradients within PAs and prioritize the protection of narrow range, low and high elevation species.

Assessing natural global catastrophic risks.

The risk of global catastrophe from natural sources may be significantly larger than previous analyses have found. In the study of global catastrophic risk (GCR), one line of thinking posits that deep human history renders natural GCRs insignificant. Essentially, the fact that natural hazards did not cause human extinction at any previous time makes it unlikely that they would do so now. This paper finds flaws in this argument, refines the theory of natural GCR, analyzes the space of natural GCRs, and presents implications for decision-making and research. The paper analyzes natural climate change, natural pandemics, near-Earth objects (asteroids, comets, and meteors), space weather (coronal mass ejections, solar flares, and solar particle events), stellar explosions (gamma-ray bursts and supernovae), and volcanic eruptions. Almost all natural GCR scenarios involve important interactions between the natural hazard and human civilization. Several natural GCR scenarios may have high ongoing probability. Deep human history provides little information about the resilience of modern global civilization to natural global catastrophes. The natural GCRs should not be dismissed on grounds of deep human history. Work on natural GCRs should account for their important human dimensions. A case can even be made for abandoning the distinction between natural and anthropogenic GCR.

Habitat suitability and dispersal of invasive Striga species under climate change in Africa

AbstractStriga species are highly invasive annual parasitic plants posing significant economic losses to the production of cereal grains and legumes in Africa. There is no explicit knowledge about the potential distribution of some important Striga species in Africa. In this study, we used the Maximum Entropy modelling algorithm (MaxEnt 3.4) to identify the bioclimatic variables that best explain the current geographic distribution of the three most aggressive Striga species in Africa. Present‐day climatically suitable areas were estimated at 14.53 million km2 (S. asiatica), 14.89 million km2 (S. hermonthica) and 12.13 million km2 (S. generioides), amounting to about 48%, 49% and 60% of the climatic space in Africa, respectively. Approximately, 11 million km2 were identified as stable and suitable across present and future periods for S. hermonthica, compared with 9 and 6 million km2 for S. asiatica and S. gesnerioides, respectively. Model projections showed that none of the study species would be able to disperse across much of northern and southern Africa. Striga hermonthica had the highest proportion (3.4%–9.3%) of colonised areas after dispersal simulations. The three Strigas predicted to be invasive in the tropical rainforest and tropical savannah of Africa. Breeding of polyploid Striga which causes sterility is considered as an alternative biological control to its spread.

Invasive woody legumes: Climatic range shifts and their relationships to functional traits

AbstractAimAnalysis of the shifts in the climatic space for invasive species between native and introduced areas is a powerful tool for understanding their distribution patterns and the factors influencing their spread into new areas. In this study, we explored the shift in climatic distribution between ranges for invasive woody legumes and how the functional traits of these species are associated with their climatic distribution.LocationGlobal.Time periodPresent.Major taxa studiedInvasive woody legumes.MethodsWe evaluated the global patterns of occupation of the climatic space for 107 invasive woody legumes in their native and introduced distribution ranges, in addition to the differences in six key functional traits. We used the trait probability density (TPD) function to estimate species probabilistic niches. We then classified species into four groups according to the climatic differences between the distribution ranges. The comparisons between the climate shift groups and the distribution ranges were evaluated with mixed linear models. Additionally, we compared the functional traits between species groups using ANOVA.ResultsOverall, we found that invasive species exhibited low to moderate climatic overlap between their native and introduced distribution ranges. However, climatic conditions in the introduced range were different from those in the native range. Invasive legumes were clustered in four groups (conserved, expansion, dissociation and unfilling), with dissociation between climate niches being the most common one. In terms of functional traits, the most relevant finding was that the species in the expansion group had larger leaves than species in the dissociation group.Main conclusionsOur results showed no consistent climatic range shift across all invasive woody legume species from their native to their introduced distribution. However, some species tended to invade climatic conditions that were different from those in their native range, supporting the hypothesis that some invasive species are able to adapt to novel environmental conditions. Finally, functional traits might be a good predictor of how these species modify their climatic spaces.

Testing for changes in rate of evolution and position of the climatic niche of clades

ABSTRACT There is solid recognition that phylogenetic effects must be acknowledged to appreciate climatic niche variability among species clades properly. Yet, most currently available methods either work at the intra‐specific level (hence they ignore phylogeny) or rely on the Brownian motion model of evolution to estimate phylogenetic effects on climatic niche variation. The Brownian motion model may be inappropriate to describe niche evolution in several cases, and even a significant phylogenetic signal in climatic variables does not indicate that the effect of shared ancestry was relevant to niche evolution. We introduce a new phylogenetic comparative method which describes significant changes in the width and position of the climatic niche at the inter‐specific (clade) level, while making no a priori assumption about how niche evolution took place. We devised the R function phylo.niche.shift to estimate whether the climatic niches of individual clades in the tree are either wider or narrower than expected, and whether the niche occupies unexpected climates. We tested phylo.niche.shift on realistic virtual species' distribution patterns applied to a phylogeny of 365 extant primate species. We demonstrate via simulations that the new method is fast and accurate under widely different climatic niche evolution scenarios. phylo.niche.shift showed that the capuchin monkeys and langurs occupy much wider, and prosimian much narrower, climatic niche space than expected by their phylogenetic positions. phylo.niche.shift may help to improve research on niche evolution by allowing researchers to test specific hypotheses on the factors affecting clades' realised niche width and position, and the potential effects of climate change on species' distributions.

Invasion patterns and niche comparison of the butterfly Cacyreus marshalli among native and non-native range

Alien species introduction is a global phenomenon involving different invasion patterns and is characterized by niche conservatism or shift. We describe the spatial distribution of Cacyreus marshalli Butler, [1898] (Lepidoptera: Lycaenidae) in its native (southern Africa) and invaded (Europe) ranges. C. marshalli is the only alien butterfly in Europe, introduced by the trade of ornamental Pelargonium plants, and might threaten native lycaenids because of the chance of its naturalization on indigenous Geranium spp. In Europe, C. marshalli is widespread in the Mediterranean basin, but absent in northern countries. We investigate invasion patterns and their temporal dynamics in Italy, the most extensively invaded country, identifying three phases and different rates of spread resulting from multiple introductions and human-mediated movements. We also characterize and compare the native and invasive ecological niches of C. marshalli with a multivariate approach based on bioclimatic, ecological and human demographic variables. The little overlap between the native and invaded niches (12.6%) indicates a shift in the realized niche of C. marshalli. While the expansion potential of C. marshalli in Europe remains constrained by the distribution of suitable host plants, our niche comparison analysis suggests the species has already invaded new ecological and climatic spaces. This includes colder areas than would be suggested by its native distribution in Africa.

Leaf morphospace in Euphorbia tithymaloides (Euphorbiaceae) was likely shaped by evolutionary contingencies rather than climate

Background and aims – Understanding whether variation in plant attributes is primarily driven by selection or historical contingencies is a main goal in evolutionary biology. We characterize leaf diversity in Euphorbia tithymaloides and identify patterns related to taxonomy, geography, biogeography, and climate that provide insights on the role of ecological and evolutionary forces in shaping its leaf diversity. Material and methods – We constructed a leaf morphospace using linear morphometric measurements derived from images (leaf maximum length and width, area, and perimeter), and calculated indexes that reflect aspects of leaf shape (leaf aspect ratio, area-perimeter ratio, obovate index, and circularity). Climatic data were extracted from WorldClim layers based on occurrence data. We visualized leaf and climate spaces with principal components analyses and used Kruskal-Wallis tests, linear models, and Mantel tests to test predictors of leaf variation (taxonomy, geography, climate). Key results – We document differences in the foliar morphospace occupied by subspecies of Euphorbia tithymaloides, and a substantial overlap in the climatic space they occupy, suggesting that foliar differences among subspecies are not likely driven by climate. Foliar morphology can be used as a proxy for subspecies in E. tithymaloides, as taxonomy explains a large proportion of variation in leaf morphology (10–60%). Geography and climate explain a small proportion of foliar variation not explained by subspecies (~3% and 5%, respectively). Temperature, precipitation, and seasonality are the climate variables with most explicative power. Conclusion – Leaf diversity in E. tithymaloides is not driven by climate, instead, it is likely the result of evolutionary contingencies faced by this species throughout its historical range expansion across the Caribbean Basin. This study shows that historical contingencies in addition to selection acting on ecological processes can shape foliar diversity and expand a lineage’s potential to explore morphological and climatic spaces.

Role of local climate zone and space syntax on land surface temperature (case study: Tehran)

Land surface temperature (LST) is one of the key parameters in the physics of land surface processes from local through global scales. Although many definitions and classifications have been proposed to better understand the causes and evolution of LST, not enough attention has been paid to their relationship to factors such as socioeconomic characteristics and spatial configuration of cities and the fact that city-level temperatures may not exist. Aiming to elucidate the effects of these factors and their relation to surface temperature dynamics, this study explored the relationship between land surface temperature (LST) variations and (using the Local Climate Zone [LCZ] method) space syntax (using Open Street Map data), and other physical and non-physical (e.g., socioeconomic) factors (and their combined effects through the Analytic Hierarchy Process (AHP) method). In the next step, a map of socio-spatial segregation, comprising four urban zones, was created. The lowest and highest mean LST figures were related to “water body” and “bare soil or sand” LCZs. Among the four segregated zones in this study, the lowest mean LST was recorded in the integrated areas. The highest mean LST was observed in the absolute (involuntary) segregation zone. The results suggested that integrated areas have a lower standard deviation than those of other zones, indicating a more consistent or stable cooling effect. In addition, the varied composition of building heights could help to mitigate the urban heat island. Finally, some considerations were presented for local climate improvement in the urban spatial structure.

Interplay between conservatism and divergence in climatic niche evolution of Brassicaceae tribe Eudemeae shaped their distribution across the different environments of the Andes

Abstract The Andean region is one of the most biodiverse areas, displaying high levels of endemism and spatial turnover of species. Tribe Eudemeae includes nine genera and 40 species distributed from the northern Andes in Colombia to the southernmost portion of the Andes in Argentina and Chile. Here, we generated a species-level phylogenetic tree to study their climatic niche evolution. We first analysed phylogenetic structure and evolutionary shifts among the main climatic spaces using model-based estimates. Second, we estimated climatic niches for each species and compared them in a phylogenetic context. In Eudemeae, three main groups of climatic spaces were found, mainly related to the northern and central Andes, the north-central portion of the southern Andes and the central-southern portion of the southern Andes. Results suggest that initial colonization of new climatic spaces in the evolution of the tribe appears to be promoted through shifts in adaptive regimes, whereas subsequent diversification of genera occurred predominantly under the same climatic regimes. This trade-off between niche conservatism and divergence appears to have modulated their diversification across the Andes and contributed to their current geographical distribution.

The complementary management of large-scale hydro-photovoltaic hybrid power systems reinforces resilience to climate change

The complementary operation of hydro-photovoltaic (PV) hybrid power systems has become a popular and promising management way in modern power systems. Since hydropower and PV power depend strongly on precipitation and solar energy, previous studies have recognized that climate change can affect the stability of standalone hydro or PV power and can threaten energy security. However, the vast majority of research studies stop at the impact assessment per se and are unexpanded to hybrid power systems. The objective of this study was to explore how the complementary operation of this integrated system could be affected by climate change and identify its resilience to climate change. A “climate-hydrology-operation” bottom-up framework was developed to determine the acceptable range of climate change in climatic exposure space where the system can succeed to operate. China’s Longyangxia hydro-PV hybrid power system was selected as the study site. Our analysis revealed that (1) the complementary operation of hydro and PV power reinforces the resilience of renewable energy sources to climate change since the range in climatic exposure space leading to system success is increased; (2) the management scheme of complementary operation shows superiority compared to separate operation according to stress tests in GCMs prediction information; and (3) the complementarity of the two sources remains stable regardless of climate change—that is, if precipitation decreases then sunshine duration increases, and evaporation increases while radiation increases—thereby allowing for a more consistent level of power generation than independent hydropower and PV plant. We propose, therefore, that managing hydropower and PV resources in a complementary manner can improve the resilience of hydro-PV hybrid power systems to climate change and can lead to more effective power benefits.

Modelling the distribution of a key habitat feature to guide future on‐ground habitat assessment for an endangered specialist songbird

AbstractSpecies distribution models (SDMs) are often used during the planning stage of reintroduction programmes to model species' occurrence with the aim of selecting potential release sites. However, for many endangered species, only a low number of records are available, leading to models with low accuracy. When planning reintroductions for rare species, an alternative approach may be to model surrogate species that are more abundant or easier to locate. Here, we modelled the distribution of white gum (Eucalyptus viminalis), the preferred food tree of the forty‐spotted pardalote (Pardalotus quadragintus), a rare songbird for which reintroduction has been proposed. Using boosted regression trees, we modelled white gum distribution under current and future climate conditions with the aim of identifying areas of high probability of occurrence that later can be used to plan on ground habitat assessments for reintroductions. Our model show areas with high probability of white gum occurrence outside its currently mapped distribution, indicating that there may be opportunities for reintroduction of pardalotes beyond their current range. Predictions of future climate scenarios showed climate space shifts, not only with some decrease but also with substantial increase in the probability of suitability for occurrence under some scenarios. Our spatial predictions for white gum may be used to design a survey to ground‐truth our model and undertake a comprehensive habitat assessment for other habitat features forty‐spotted pardalotes need to persist. The approach used in our study may be used for other highly specialized species, not only in the context of reintroduction planning but also in the general management of data‐poor specialist species that depend on a more common resource.

The North American tree‐ring fire‐scar network

AbstractFire regimes in North American forests are diverse and modern fire records are often too short to capture important patterns, trends, feedbacks, and drivers of variability. Tree‐ring fire scars provide valuable perspectives on fire regimes, including centuries‐long records of fire year, season, frequency, severity, and size. Here, we introduce the newly compiled North American tree‐ring fire‐scar network (NAFSN), which contains 2562 sites, >37,000 fire‐scarred trees, and covers large parts of North America. We investigate the NAFSN in terms of geography, sample depth, vegetation, topography, climate, and human land use. Fire scars are found in most ecoregions, from boreal forests in northern Alaska and Canada to subtropical forests in southern Florida and Mexico. The network includes 91 tree species, but is dominated by gymnosperms in the genus Pinus. Fire scars are found from sea level to >4000‐m elevation and across a range of topographic settings that vary by ecoregion. Multiple regions are densely sampled (e.g., >1000 fire‐scarred trees), enabling new spatial analyses such as reconstructions of area burned. To demonstrate the potential of the network, we compared the climate space of the NAFSN to those of modern fires and forests; the NAFSN spans a climate space largely representative of the forested areas in North America, with notable gaps in warmer tropical climates. Modern fires are burning in similar climate spaces as historical fires, but disproportionately in warmer regions compared to the historical record, possibly related to under‐sampling of warm subtropical forests or supporting observations of changing fire regimes. The historical influence of Indigenous and non‐Indigenous human land use on fire regimes varies in space and time. A 20th century fire deficit associated with human activities is evident in many regions, yet fire regimes characterized by frequent surface fires are still active in some areas (e.g., Mexico and the southeastern United States). These analyses provide a foundation and framework for future studies using the hundreds of thousands of annually‐ to sub‐annually‐resolved tree‐ring records of fire spanning centuries, which will further advance our understanding of the interactions among fire, climate, topography, vegetation, and humans across North America.

Predicting the potential distribution of Dactylorhiza hatagirea (D. Don) Soo-an important medicinal orchid in the West Himalaya, under multiple climate change scenarios.

Climate variability coupled with anthropogenic pressures is the most critical driver in the Himalayan region for forest ecosystem vulnerability. Dactylorhiza hatagirea (D.Don) Soo is an important yet highly threatened medicinal orchid from the Himalayan region. Poor regenerative power and growing demand have resulted in the steep decline of its natural habitats populations. The present study aims to identify the habitat suitability of D. hatagirea in the Western Himalaya using the maximum entropy model (MaxEnt). The community climate system model (CCSM ver. 4) based on representative concentration pathways (RCPs) was used to determine suitable future areas. Sixteen least correlated (< 0.8) bioclimatic, topographical and geomorphic variables were used to construct the species climatic niche. The dominant contributing variables were elevation (34.85%) followed by precipitation of the coldest quarter (23.04%), soil type (8.77%), land use land cover (8.26%), mean annual temperature (5.51%), and temperature seasonality (5.11%). Compared to the present distribution, habitat suitability under future projection, i.e., RCP 4.5 and RCP 8.5 (2050 and 2070), was found to shift to higher elevation towards the northwest direction, while lower altitudes will invariably be less suitable. Further, as compared to the current distribution, the climatic niche space of the species is expected to expand in between11.41-22.13% in the near future. High habitats suitability areas are mainly concentrated in the forest range like Dharchula and Munsyari range, Pindar valley, Kedarnath Wildlife Sanctuary, West of Nanda Devi Biosphere Reserve, and Uttarkashi forest division. The present study delineated the fundamental niche baseline map of D. hatagirea in the Western Himalayas and highlighted regions/areas where conservation and management strategies should be intensified in the next 50 years. In addition, as the species is commercially exploited illegally, the information gathered is essential for conservationists and planners who protect the species at the regional levels.

Species Delimitation of the Atlantic Forest Endemic Inga subnuda (Leguminosae, Caesalpinioideae, Mimosoid Clade) Subspecies Based on Morphological, Ecological, and Palaeoecological Data

Abstract— Inga subnuda is one of 31 Inga species endemic to the Brazilian Atlantic Forest and is currently treated as having two subspecies (I. subnuda subsp. subnuda and I. subnuda subsp. luschnathiana). However, due to intermixed leaf and floral traits, these subspecies are difficult to morphologically distinguish. This study aimed to better understand the boundaries of these two subspecies and to test if these taxa should be treated at the species level. Morphological variation and bioclimatic data related to the two subspecies of the complex were assessed using multivariate morphometric analyses and ecological niche modeling. Different groups were recognized using morphological quantitative characters. The climatic space was similar but not identical, and recent climatic cycles that could have shaped the current distributions of the subspecies are discussed. The results of our integrative study suggest the subspecies are distinct species. Thus, we propose changing the status of I. subnuda subsp. luschnathiana to the rank of species. The new taxon is described and illustrated.

Climatic Niche of Vegetation Greenness Is Likely to Be Conservative in Degraded Land

Satellite data have been widely used to study changes in vegetation greenness in geographical space; however, this change is rarely considered in climatic space. Here, the climatic niche dynamics of vegetation greenness, represented by the normalized difference vegetation index (NDVI), was quantified in the climate space of the Loess Plateau, a piece of degraded land greening significantly from 2000 to 2018. The niche similarity test was used to examine the niche conservatism of vegetation greenness during the 19 years of restoration. The results show that the climate niche of vegetation greenness is always more similar than expected. The stability niche occupied most parts (83–98%) of their climatic niche, and niche overlap reached 0.52–0.69. Climate niche conservatism suggests that potential greenness constructed by statistical methods could be used as a criterion or baseline for ecosystem function restoration on the Loess Plateau. The study also suggests that the integrated niche similarity test in decision-making for restoration of degraded land will clarify our understanding of the climatic niche dynamics of vegetation greenness and the making of forecasts.

Understanding climate change impacts on biome and plant distributions in the Andes: Challenges and opportunities.

AimClimate change is expected to impact mountain biodiversity by shifting species ranges and the biomes they shape. The extent and regional variation in these impacts are still poorly understood, particularly in the highly biodiverse Andes. Regional syntheses of climate change impacts on vegetation are pivotal to identify and guide research priorities. Here we review current data, knowledge and uncertainties in past, present and future climate change impacts on vegetation in the Andes. Location: Andes. Taxon: Plants.MethodsWe (i) conducted a literature review on Andean vegetation responses to past and contemporary climatic change, (ii) analysed future climate projections for different elevations and slope orientations at 19 Andean locations using an ensemble of model outputs from the Coupled Model Intercomparison Project 5, and (iii) calculated changes in the suitable climate envelope area of Andean biomes and compared these results to studies that used species distribution models.ResultsFuture climatic changes (2040–2070) are projected to be stronger at high‐elevation areas in the tropical Andes (up to 4°C under RCP 8.5), while in the temperate Andes temperature increases are projected to be up to 2°C. Under this worst‐case scenario, temperate deciduous forests and the grasslands/steppes from the Central and Southern Andes are predicted to show the greatest losses of suitable climatic space (30% and 17%–23%, respectively). The high vulnerability of these biomes contrasts with the low attention from researchers modelling Andean species distributions. Critical knowledge gaps include a lack of an Andean wide plant checklist, insufficient density of weather stations at high‐elevation areas, a lack of high‐resolution climatologies that accommodates the Andes' complex topography and climatic processes, insufficient data to model demographic and ecological processes, and low use of palaeo data for distribution modelling.Main conclusionsClimate change is likely to profoundly affect the extent and composition of Andean biomes. Temperate Andean biomes in particular are susceptible to substantial area contractions. There are, however, considerable challenges and uncertainties in modelling species and biome responses and a pressing need for a region‐wide approach to address knowledge gaps and improve understanding and monitoring of climate change impacts in these globally important biomes.

Leaf trait association in relation to herbivore defense, drought resistance, and economics in a tropical invasive plant

Exploring how functional traits vary and covary is important to understand plant responses to environmental change. However, we have limited understanding of the ways multiple functional traits vary and covary within invasive species. We measured 12 leaf traits of an invasive plant Chromolaena odorata, associated with plant or leaf economics, herbivore defense, and drought resistance on 10 introduced populations from Asia and 12 native populations from South and Central America, selected across a broad range of climatic conditions, and grown in a common garden. Species' range and climatic conditions influenced leaf traits, but trait variation across climate space differed between the introduced and native ranges. Traits that confer defense against herbivores and drought resistance were associated with economic strategy, but the patterns differed by range. Plants from introduced populations that were at the fast-return end of the spectrum (high photosynthetic capacity) had high physical defense traits (high trichome density), whereas plants from native populations that were at the fast-return end of the spectrum had high drought escape traits (early leaf senescence and high percentage of withered shoots). Our results indicate that invasive plants can rapidly adapt to novel environmental conditions. Chromolaena odorata showed multiple different functional trait covariation patterns and clines in the native and introduced ranges. Our results emphasize that interaction between multiple traits or functions should be considered when investigating the adaptive evolution of invasive plants.

Macroevolutionary dynamics of climatic niche space.

How and why lineages evolve along with niche space as they diversify and adapt to different environments is fundamental to evolution. Progress has been hampered by the difficulties of linking a robust empirical characterization of species niches with flexible evolutionary models that describe their evolution. Consequently, the relative influence of abiotic and biotic factors remains poorly understood. Here, we characterize species' two-dimensional temperature and precipitation niche space occupied (i.e. species niche envelope) as complex geometries and assess their evolution across all Aves using a model that captures heterogeneous evolutionary rates on time-calibrated phylogenies. We find that extant birds coevolved from warm, mesic climatic niches into colder and drier environments and responded to the Cretaceous-Palaeogene (K-Pg) boundary with a dramatic increase in disparity. Contrary to expectations of subsiding rates of niche evolution, our results show that overall rates have increased steadily, with some lineages experiencing exceptionally high evolutionary rates, associated with the colonization of novel niche spaces, and others showing niche stasis. Both competition- and environmental change-driven niche evolution transpire and result in highly heterogeneous rates near the present. Our findings highlight the growing ecological and conservation insights arising from the model-based integration of comprehensive environmental and phylogenetic information.