Climate change is a threat to global biodiversity, with changes to mean temperatures and increasing frequency and intensity of extreme weather events. Heatwaves in particular pose a threat to species’ persistence, as temperatures may rise above physiological tolerance. However, individuals rarely experience temperatures measured at the macroclimatic scale: topographic or vegetation differences result in microclimates that provide cool refugia (local temperatures below ambient) or even result in heat traps (local temperatures above ambient) during heatwaves. However, little is known about the stability of microclimates through a period of regional warming. In this study, we recorded microclimate temperatures across different microhabitats within a calcareous grassland nature reserve in Bedfordshire, UK, in 2018, 2019 and 2022. During this time, six heatwave events occurred, including the highest air temperatures ever recorded in the UK. We found that the ability of microhabitats to offset air temperatures varied with topographic aspect, slope, amount of bare ground, shelter, vegetation height, and vegetation type, with encroaching scrub and north-facing slopes showing the strongest abilities to maintain relatively stable microclimate temperatures with increasing air temperatures, in contrast to short vegetation on south-facing slopes which became heat traps. However, no combinations of environmental structures consistently maintained cool refugia during heatwaves. Microclimate temperatures were amplified close to the ground, whereas at 50 cm height temperatures were more stable and similar to the macroclimate temperature, therefore surface-dwelling species, such as many insects, may be particularly vulnerable to extreme heat. We identified a breakdown in the ability of microhabitats to maintain cool refugia above 7 °C, implying cool refugia become increasing rare and unpredictable with increasing temperatures. Our results indicate that many microhabitats will amplify the effects of climate change rather than mitigate them. The innate unpredictability and scarcity of extreme temperature events makes them an evolutionary challenge; instead, microclimatic refugia are often suggested as a way for species to cope under climate change. By comparing microclimate temperatures to macroclimate temperatures (from a nearby weather station) in central England, we highlight how variable local temperatures can be at fine scales relevant to small surface-dwelling organisms, with microclimate temperatures differing by as much as 20 °C. Microclimate performance changed with increasing temperature, with more heat traps (microclimate temperatures above ambient) and fewer cool refugia (microclimate temperatures below ambient). No environmental variables tested reliably maintained cool refugia at high temperatures. Ground-level microclimate temperatures were amplified compared to temperatures at 50 cm height, implying that surface-dwelling organisms in grasslands, including many insects, may be particularly vulnerable compared to species that fly, climb, or live in tall vegetation.

Pantropical taxa with broad and changing distributions provide useful models for assessing drivers of tropical tree biodiversity. Originating at the Eocene-Oligocene boundary, Xylopia is a vertebrate-dispersed woody plant genus with ca. 190 species evenly distributed across the Tropics. How did biogeographic and ecological transitions in this genus shape its broad present-day distribution? We analysed these transitions using ancestral area, climatic and spatial phylogenetic reconstructions, based on an extensive nuclear phylogeny and a curated dataset of occurrence records. The ancestral area was reconstructed as palaeotropical. The genus then underwent two dispersals from Africa, one to the Asia-Pacific area and one to the Neotropics. While niche conservatism in continental rain forests continued, the genus repeatedly transitioned to subhumid, inundated and ultramafic environments. Transitions from rain forests to subhumid environments increased in the Afrotropics as many rain forest groups underwent extinction. Association with inundated habitats, frequent in the early evolution of the genus, became sporadic. Ultramafic transitions occurred in five clades. Xylopia is present on 51 tropical islands; single-island endemics make up ca. 90% of insular species. Repeated dispersals took place between Africa and Madagascar, the Sunda and Sahul plates in the Asia-Pacific and from Central America to the Caribbean. Island distributions indicate overdispersion to remote islands, as well as limited radiations and stepping-stone dispersals. Novel environments, including islands, acted largely as sinks, together encompassing about half the species in the genus. A suite of traits promoting long-distance dispersal by a variety of non-resident birds, combined with the capacity for habitat transitions, were fundamental drivers of pantropical expansion and diversification. These drivers operated repeatedly in all regions, while idiosyncratic historical factors determined the timing and routes of dispersals. Age and distribution of basal grade lineages suggest that the ancestral Xylopia lineage occupied Eocene Boreotropical forests, moving southwards and diversifying independently in the Afrotropic and Asia-Pacific areas of the Palaeotropics. Biogeographic stochastic mapping estimated high regional in situ speciation (89.8%) amongst total biogeographic events for Xylopia . The plants provide high value seed rewards taken by birds that transit long distances and between habitats, promoting long-distance dispersal. Xylopia exhibits overdispersion even to isolated islands, but there is no significant correlation between species richness and isolation index. In response to Miocene aridification and shifts to monsoon climates in the Afrotropics, Xylopia dispersed across multiple lineages, including transitions to subhumid habitats. Ultramafic species occur on islands throughout the range of Xylopia ; radiations took place in Xylopia sect. Xylopia on Cuba and in Xylopia sect. Stenoxylopia on New Guinea and New Caledonia.

The loss of American chestnut ( Castanea dentata Marsh. Bork.) caused ecological change in many community types of the eastern United States. Restoration is challenged by climate change and two naturalised invasive non-native diseases, chestnut blight (caused by Cryphonectria parasitica [Murrill] M.E. Barr) and Phytophthora root-rot (caused by Phytophthora cinnamomi Rands). Learning how to overcome these challenges in the southern portion of the former chestnut range may make range-wide restoration efforts more successful because these pressures are likely strongest in southern portions of the range. To establish a baseline of chestnut distribution and environmental correlates, we used ca. 1830 land lottery maps to document the historic abundance and distribution of chestnut in Georgia. Land lottery surveyors documented 717,901 trees within our study area, identifying 15,710 as chestnut. We used their data to create a species distribution model with soil and landform predictors, factors possibly related to disease risk and predicted the relative habitat suitability for chestnut throughout much of the State. Our results revealed that long-held assumptions about chestnut range and abundance in Georgia are incorrect. Chestnut was less common in northern Georgia and more common in the Piedmont than previously postulated, and chestnut ranged well into the Coastal Plain. Soil and landform variables adequately predicted chestnut distribution and habitat suitability models predicted that chestnut occupied a wide diversity of habitats; habitat preferences were complex and differed by physiographic province. All the models agreed that chestnut preferred higher elevation, more slope and landform curvature, but the relationship of chestnut to other variables was difficult to generalise and may have been context dependent. These results can be used to guide re-introduction and maximise success in the face of changing climate and non-native disease risk. Anecdotal accounts limit the historic range of American chestnut in Georgia to the Blue Ridge, Appalachian Plateau and Ridge and Valley physiographic provinces; however, historic land lottery maps dating from the early 1800s documented chestnut throughout the Georgia Piedmont and much of the Coastal Plain; Chestnut was found in a wide range of Georgia habitats in every physiographic province before the introduction of non-native pathogens, sometimes in high abundance and sometimes as less dense components of habitats with other dominant or co-dominant species; Although patterns of chestnut distribution were largely driven by elevation and slope, other environmental factors including aspect, landform curvature, number of frost-free days, percentage clay in soil and soil pH significantly influenced chestnut distribution in Georgia. These patterns varied by physiographic province, suggesting chestnut habitat was not monotypic across Georgia; Restoration efforts that recognise regional differences and the full suite of diverse habitats that once included chestnut may be more likely to succeed. Our models and regional habitat suitability maps can be used to guide planting site selection, while also considering the large variability inherent in ecological restoration of chestnut across multiple physiographic provinces; As they are relatively fine scale, edaphic and landform factors are useful in predicting suitable habitat for plants and may be used in conjunction with climate change predictions to guide site selection for species reintroductions that will be sustainable into the foreseeable future.

This study aims to analyse plant endemism in Armenia. The richness of the republic’s flora was assessed in terms of the representation of endemic taxa. The distribution of endemic plant species was identified and analysed both within the republic and across altitudinal belts and major ecosystems. The greatest number of endemic taxa belongs to the families Rosaceae, Asteraceae, Fabaceae, and Poaceae, with the richest genera being Pyrus, Astra­galus, and Psephellus. Most endemic species are confined to the arid regions of the republic, particularly the middle mountain belt and grassy ecosystems. Several “centres of endemism” were identified, where populations of multiple endemic species coexist in a small area. The relevant government organisations must prioritise these centres when creating new protected natural areas. We identified 139 endemic taxa (species and/or subspecies) of vascular plants belonging to 27 families and 69 genera in modern Armenia. For Armenia, we calculated Bykov’s index (le = Ef/En, where Ef represents the real percentage of endemic taxa, and En denotes the expected or normal percentage of endemic taxa in the basic graph) to be 3.7, which is 3.7 times higher than the norm. This index surpasses that of renowned countries such as South Africa (3.6), Greece (2.1), Turkey, Cyprus (~2), and the Caucasus as a whole (1.3). This finding suggests that Armenia is one of the most significant territories in terms of plant diversity within the global biodiversity hotspot of the Caucasus. The greatest number of endemics belongs to the Rosaceae family, particularly due to a high diversity within the genus Pyrus (10 species), followed by the Asteraceae, Fabaceae, and Poaceae families. The Caryophyllaceae (10 species) and Scrophulariaceae (eight species) families follow. At the genus level, Pyrus has 10 local endemic species, while the largest genus in Armenia, Astragalus, has seven endemic species, as does Psephellus, followed by Centaurea (six species). The highest number of endemic vascular plant taxa is found in the Yerevan and Darelegis floristic regions, with fewer in the Aparan, Shirak, and Meghri regions. The majority of these taxa thrive in the arid regions of the Armeno-Iranian province of the Ancient Mediterranean subkingdom. Most of these species should be classified as neoendemics, formed in arid conditions. In contrast, the majority of endemics associated with the “Caucasian root,” which flourish in the more humid conditions of the remaining floristic regions of Armenia, are likely paleoendemics, preserved from glacial and postglacial periods. The overwhelming majority of endemic vascular plant taxa in Armenia are confined to herbaceous habitats—84 species. Significantly fewer are found in petrophyte habitats and those with no or poorly developed vegetation—29 species, in forest and shrub habitats—25 species each, and in aquatic habitats, where only seven taxa are present. No endemic species or subspecies have been recorded in marsh habitats. This distribution can be attributed to the fact that herbaceous habitats occupy nearly two-thirds of Armenia’s territory. Furthermore, most endemics are associated with arid ecosystems, which are predominantly represented by habitats of this category.

This study extends the Sea-Level Sensitive dynamic model of marine island biogeography by integrating the dynamics of fusion-fission islands during glacial-interglacial cycles with marine island biogeography theory. We discuss the variations in littoral area due to Pleistocene sea-level changes and their effect on the evolutionary rates of splitting, extinction, and merging of populations, as well as on the speciation rates of marine shallow-water organisms. Here, we introduce three different types of fusion-fission islands: Solum islands, i.e., islands that have never been merged with neighbouring islands (at depths shallower than 50 m) during sea-level low stands associated with glacial episodes; Soror islands, i.e., islands that are subjected to fusion-fission cycles due to sea-level changes and thus may be functionally connected or separated depending on the amplitude of sea level changes; and Moliones islands, where two or more islands are functionally connected from a marine point of view, as the seafloor depth separating them is always shallower than 50 m, regardless of sea level. For this study, we selected 324 islands located in temperate and tropical climates, and representative of a broad geographic distribution, which were classified accordingly: 50 Solum islands, 77 islands making up 20 groups of Soror islands, and 197 islands from 34 groups of Moliones islands. Sea-level variation during glacial-interglacial cycles induced changes in the insular littoral area (ILA), resulting in five general types of curves of ILA change herein described. These ILA curves depend on the depth distribution across the shelves, which, in turn, depends on several variables, including the age of the island, the tectonic setting, the presence of submarine and subaerial terraces, and also on the presence/absence of coral reefs. Finally, we provide several predictions on the frequencies of marine population splitting, extinction, and merging events, as well as on the speciation rates of shallow-water marine organisms, according to the respective island types. Highlights We extend the Sea-Level Sensitive dynamic model of marine island biogeography theory to include the special case of fusion-fission islands. The dynamics of fusion-fission islands during glacial-interglacial cycles are relevant to evolutionary and biogeographic studies. We introduce new concepts (Solum, Soror, and Moliones islands) to designate islands according to the impact of glacial episodes and associated sea-level low stands on their marine biota. Five general types of curves of insular littoral area (ILA) change generated by sea-level variations during glacial-interglacial cycles are described. We hypothesize that the frequencies of marine population splitting, extinction, and merging events, as well as the speciation rates of shallow-water marine organisms, vary according to the island type.

The dwarf pond snail Galba truncatula (O.F. Müller, 1774) is a widespread freshwater species and a key intermediate host of Fasciola spp. Despite its ecological and medical significance, the evolutionary structure of its populations remains incompletely resolved. Using 78 mitochondrial COI sequences, including newly obtained material from Eastern Europe, Central Asia, and Caucasus, we reconstructed the phylogeographic pattern of Galba truncatula across Western Palearctic. Our analyses reveal the presence of three distinct phylogenetic lineages. A deeply divergent group, represented by a small number of sequences, occurs sympatrically with the main clade in Western Europe. The main clade, comprising the majority of sequences, is split into two geographically structured subclades: a western lineage (Western Europe and North Africa) and an eastern lineage (Eastern Europe, Caucasus, and Central Asia). Both major lineages are represented in South America, suggesting at least two independent colonization events. We propose that the initial divergence between the eastern and western lineages likely began in the early Pleistocene, whereas their present-day distribution may have been shaped by isolation during the Last Glacial Maximum. We reconstructed the phylogeographic structure of Galba truncatula using COI sequences from Eurasia and South America. Three distinct lineages were identified, including a deeply divergent group occurring sympatrically in Western Europe. The main lineage is split into eastern and western clades, likely diverging in the early Pleistocene. Both clades are represented in South America, indicating at least two independent colonization events. Our findings challenge the hypothesis of a South American origin and highlight the role of glacial history in shaping current diversity.

Biogeography has traditionally relied on species-based measures of biodiversity, partially reflecting the processes shaping spatial patterns. Incorporating the evolutionary relationships among taxa can provide a greater understanding of how distinct processes define different regional patterns over time. Here, we describe the biogeography of marine ray-finned fishes (Actinopterygii) in Aotearoa New Zealand and adjacent areas of the Southwest Pacific using phylogenetic measures of richness and endemism. Defining a geographic area of 30° latitude by 20° longitude that encompasses New Zealand’s main and offshore islands, we compiled distributional maps for 313 taxa occurring in 0–500 m waters using AquaMaps, a web-based tool that generates occurrence probability maps based on environmental and occurrence data. We describe spatial patterns of biodiversity with species and phylogenetic metrics of richness and endemism, including phylogenetic diversity and phylogenetic endemism, using a comprehensive molecular phylogeny of New Zealand’s marine fishes. To identify endemism centres, we employ the “categorical analysis of neo- and paleoendemism” (CANAPE) method which distinguishes locations with an over-representation of spatially rare short phylogenetic branches (neoendemism) and spatially rare long phylogenetic branches (paleoendemism). Latitudinal patterns of richness and endemism differ, with richness peaking at 35°S along the North Island, while endemism reaches maximum values in the northernmost oceanic islands where neoendemism dominates. Significant paleoendemism clusters around two coastal areas of mainland New Zealand. Our study shows that richness and endemism hotspots are geographically distinct for New Zealand’s marine fishes, likely the result of distinct acting processes. The richness maximum appears to be the result of a range overlap between distantly related tropical taxa shifting towards high latitudes and a lower number of older temperate taxa. Neoendemism is likely driven by the isolation of young volcanic islands, and coastal paleoendemism might be the legacy of locally stable environmental conditions that served as a refuge for relict lineages over time. We identify areas where evolutionary processes have left a signal unnoticed by species richness alone. Northern subtropical marine fish assemblages are composed of a heterogeneous mixture of distantly related taxa. Southern temperate and subantarctic areas are characterized by the presence of a low number of old lineages as well as the absence of extremely young and old taxa. We generate a phylogenetic landscape from which future biogeographic research can test hypotheses to unveil underlying evolutionary and ecological processes.

We explored how patch area and isolation from a mainland affect biodiversity distribution patterns in anthropogenic monocultures resembling habitat islands and surrounded by a structurally contrasting matrix. Grassland afforestation with Eucalyptus plantations ongoing in Río de la Plata grassland provides a valuable opportunity to study how these spatial features relate to forest mainland-related taxonomic and functional diversity. We sampled birds in 17 Eucalyptus plantations located in eastern Entre Ríos province, in Argentina, using the point count technique. We measured patch area and distance from a forest mainland. We also recorded vegetation structure variables within plantations to control for the potential influence of habitat structural complexity. We analyzed the relationships between the spatial attributes of plantations (area and isolation) and species richness, functional richness, and functional originality using generalized linear models (GLMs) and Analysis of Deviance. Plantation area held no influence whatsoever on either taxonomic or functional diversity of forest birds inhabiting plantations. In contrast, we found distance to the nearest riparian forest to negatively affect species richness, functional richness, and functional originality of forest birds in Eucalyptus plantations. Unlike most natural habitat islands, traditional species–area relationship patterns seem to be hindered in strictly managed anthropogenic monocultures, probably due to the lack of a strong link between patch area and habitat diversity, and forest bird functional diversity was also not related to patch area. Instead, our study suggests that in anthropogenic monocultures isolation from a mainland promotes less diverse and more redundant assemblages. We adopted an island biogeography approach to study bird biodiversity patterns in Eucalyptus plantations embedded within agricultural-pastoral grasslands. Unlike natural habitat islands, plantation size had no influence on forest bird diversity, challenging traditional species–area relationship patterns. Distance from the natural forest mainland negatively affected both taxonomic and functional diversity of forest bird communities. Isolation from natural forests led to more functionally redundant bird assemblages in Eucalyptus plantations.

Triatominae , commonly known as kissing bugs, are hematophagous insects of significant epidemiological concern due to their role as vectors for Trypanosoma cruzi, the causative agent of Chagas disease. Their widespread distribution across the Americas is a result of complex evolutionary and biogeographical processes. The objective of this research was to quantify the timing and directionality of Triatominae lineage dispersals throughout the New World. Using a time-calibrated phylogeny derived from genomic data and fossil evidence, anagenetic dispersals were modeled by the dispersal-extinction-cladogenesis (DEC) model followed by biogeographic stochastic mappings (BSM). Threshold regression analysis was employed to identify distinct dispersal phases and their predominant routes across 11 defined bioregions. Ancestral areas estimated by the DEC model indicated multiple areas as the ancestral range for the entire clade, with northern South America (BRG-18-19-20) identified as the most likely, albeit with small probability. A biphasic pattern in normalized dispersal rates was identified, characterized by two significant breakpoints at 50 Ma and 30 Ma, delineating three distinct phases. Phase A (60–50 Ma) showed high dispersal from the Amazonian region towards northern South America and Mesoamerica, potentially linked to warmer global temperatures. Phase B (50–30 Ma) exhibited a notable decline in dispersal activity, possibly influenced by global cooling. Phase C (30–0 Ma) marked a resurgence in dispersal, displaying complex and frequent patterns, including bidirectional exchanges between Mesoamerica and the Nearctic, and movements along the South American dry diagonal and along Atlantic bioregions. This comprehensive reconstruction provided novel insights into the anagenetic dispersal processes that shaped the historical and contemporary distribution of Triatominae species across the Americas. A time-calibrated phylogeny places the origin of Triatominae at ~59.2 million years ago, indicating that the diversification of this subfamily may have occurred earlier than previously proposed in the literature. Analyses revealed a marked reduction in dispersal events among Triatominae lineages between 50 and 30 million years ago, coinciding with a phase of global cooling. Specific directional dispersal routes were reconstructed for each phase, revealing early Amazonian outflows and later complex bidirectional exchanges across the Americas. This comprehensive macroevolutionary reconstruction provided critical insights into the historical biogeography and current distribution patterns of Triatominae, vectors of Chagas disease.

Several studies show that species richness patterns are determined by current climate and Pleistocene climatic oscillations. Additionally, habitat availability is an important driver of current species diversity, especially in aquatic ecosystems where lentic (standing water) and lotic (running water) habitats play distinct roles in species composition and richness. Odonates, an order of aquatic insects, exhibit distinct adaptive traits in response to climate and to lentic and lotic habitats. In this work, we study the species richness patterns of European odonates and the influence of past and current climate, and habitat availability. The study covers 124 species distributed across Europe (excluding Russia and all European islands except Great Britain and Ireland), divided into three groups: all odonates, lentic species, and lotic species. Notably, lentic species total 70% of the studied Odonata species, thus influencing overall species richness patterns. We analyzed their diversity in Northern and Southern Europe, divided according to the 0 °C Isotherm of the Last Glacial Maximum (21,000 years ago), using data on current and Last Glacial Maximum climate (temperature and precipitation), as well as on habitat data from land cover and hydrology GIS maps. Our results suggest that the species richness patterns of dragonflies and damselflies are largely determined by the water-energy balance, with temperature influencing the decline in richness towards the north and precipitation determining the decline towards the south. Past climate oscillations affect species richness in southern and northern Europe. Habitat availability also influences odonate diversity to a lesser extent, with a positive correlation between lotic species richness and their habitat availability. In contrast, lentic species richness showed a negative correlation with the availability of lentic habitats. We evaluate whether the variation of dragonfly species richness across Europe is determined by current climate, the climatic conditions during the last ice age, and the availability of freshwater habitats. Dragonfly species richness is higher in Central Europe and decreases both northwards and southwards from there. These variations are primarily determined by current and past climate, and to a lesser extent by habitat availability. Temperature determines the northward decrease in species richness, while the southward decrease is so by precipitation. The last ice age climate had a greater influence than current climate in northern Europe, while in southern Europe current climate has a greater influence, particularly for species related to standing water habitats. Species richness is higher in areas with more rivers and water courses, while the relationship with the availability of standing water habitats is more nuanced.