Mediterranean Biogeographical Regions Research Articles

Hymenochaete ametzii sp. nov. (Hymenochaetales, Basidiomycota), an endangered bark-dwelling species inhabiting old Quercus pyrenaica trees from the Iberian Peninsula

Bark-dwelling fungi represent a group of ecologically highly specialized organisms. This study deals with an undescribed species of Hymenochaete characterized by specifically inhabiting the bark of Pyrenean oak (Quercus pyrenaica), and producing effuse-reflexed basidiomata and mainly globose to subglobose basidiospores. Maximum Likelihood and Bayesian analyses of the nuclear ITS-LSU regions revealed that the sequences of H. ametzii form a monophyletic group with a low intraspecific variation and substantially different from closest taxa, further supporting its recognition as a species. The seven localities H. ametzii is known from are old forests with a long ecological continuity, containing large old Q. pyrenaica trees, and are located in the supramediterranean belt of the Mediterranean biogeographical region. Based on habitat availability and field counts of colonized trees, the global population of H. ametzii is estimated at 8,670 mature individuals. Considering that the traditional use of old Q. pyrenaica stands ceased several decades ago in the Iberian Peninsula, with a consequent decline in habitat quality and availability, it is concluded that H. ametzii is Endangered (EN) according to the IUCN criteria.

EU2030 biodiversity strategy: Unveiling gaps in the coverage of ecoregions and threatened species within the strictly protected areas of Italy

About 19 % of the Italian territory is covered by protected areas (PAs), 5.1 % of which fall in IUCN categories Ia and II, which can be considered strictly protected areas (StPAs). The 2030 EU Biodiversity Strategy sets a target of 30 % coverage for PAs (of which 10 % should be StPAs). We assessed the area coverage of StPAs, for the territory of Italy, with respect to biogeographical regions, ecoregions, elevation range, habitats, and the distribution of species threatened with extinction according to the IUCN Red List (Vulnerable, VU; Endangered, EN; or Critically Endangered, CR). We found that most of the StPAs are located in the Mediterranean biogeographical region, followed by the Alpine and Continental regions, and that the spatial distribution of such protected areas is biased towards higher elevation. Moreover, we found that three of the fourteen terrestrial ecoregions of Italy are not protected at all by StPAs (i.e., Illyrian, Ligurian-Provencal, and Central-Adriatic), while the Po Plain and the Sicilia Sections are only marginally protected. Moreover, nine habitats are not covered by any StPAs including one priority habitat (Inland salt meadows). Finally, we found unprotected species among freshwater fish (21), amphibians (3 VU, 3 CR), reptiles (1 CR), birds (2 NE), mammals (1 VU), and plants (20 VU, 14 EN, 21 CR). Our findings suggest that the current amount and spatial distribution of StPAs of Italy are far from the targets of the EU Biodiversity Strategy and needs improvements.

Acoustic differentiation of calls in the closely related Dartford (Curruca undata), Marmora’s (Curruca sarda) and Balearic Warblers (Curruca balearica)

ABSTRACT Acoustic differentiation in bird vocalisations is a key process for speciation. Calls have received little attention compared to songs, but their simplicity facilitates analysis using mathematical, non-biased, tools, as they can be described by means of very basic variables. Here, we combined PERMANOVA and machine learning techniques to analyse the differentiation in the contact calls of the closely related Dartford (Curruca undata), Marmora’s (C. sarda) and Balearic (C. balearica) warblers (formerly in the genus Sylvia). The calls of the three species differed clearly, consistent with phylogenetic reconstructions based on DNA sequences. In C. sarda, significant call differences were observed between the population wintering in Tunisia (migratory) and those of Sardinia and Corsica (mainly sedentary). Such divergence could be favoured by assortative mating of migrant and resident individuals, working as a matching mechanism for reproductive isolation in sympatry. In contrast, there was no clear separation between the accepted subspecies of C. undata. We found, however, significant differences between the Atlantic and Mediterranean biogeographical regions in this species. The divergences detected within C. undata and C. sarda deserve further investigation, using additional traits to elucidate the phylogenetic status of these groups, as well as the factors driving their diversification.

Dead wood volume-to-carbon conversion factors by decay class for ten tree species in Croatia and eight tree genera globally

Dead wood (DW) is an important forest carbon (C) pool for which the reporting of C stock changes within the National Greenhouse Gas Inventory Report (NIR) is mandatory. The use of DW volume-to-carbon conversion factors by decay classes, i.e. DW basic density (DWBD) and C fraction (CF), or C density (CD) as their product, facilitates more accurate estimates of DW C stocks and C stock changes.We present DW conversion factors, namely DWBD, CF, and CD, by decay classes for six broadleaf (Quercus robur L., Carpinus betulus L., Alnus glutinosa Garnet., Fraxinus angustifolia Vahl., Fagus sylvatica L., and Quercus ilex L.) and four conifer (Abies alba Mill., Picea abies (L.) Karst., Pinus nigra Arnold and Pinus pinaster Aiton) tree species from Continental, Alpine and Mediterranean biogeographical regions of Croatia. For each tree species DW logs (diameter from 5 to 30 cm) were visually categorized into four decay classes and nine discs per decay class were sampled. In addition, three healthy trees of each species were felled down at the same location for estimating the basic density of fresh wood (BWD, decay class 0) and calculation of species-specific relative density reduction patterns. In total, 390 discs were sampled and analysed in the laboratory.Our results show that broadleaves, on average, have higher DWBD than conifers (p < 0.05) for decay classes 0–3, but for decay class 4 no difference (p < 0.05) was observed between these two tree species groups. Unlike for DWBD, CF showed no trend with decay class, but a difference (p < 0.05) in the average CF was found between broadleaves and conifers with the mean (s.e.) of 47.65% (0.12%) and 50.67% (0.23%), respectively. The application of decay class-specific CD by forest land use strata used in the Croatian NIR yielded 11.1% − 26.6% lower DW C pool estimates, compared to the current ones calculated using BWDs and default CF.DWBD data from our study was compared with DWBD data from the literature. We observed good agreement between national species-specific DWBD and global genus-specific DWBD for the great majority of investigated tree genera and decay classes. Therefore, we combined our results with the published data to provide a global DWBD meta-means with confidence intervals by decay classes for eight tree genera. Our results suggest that in the absence of local or national DWBD data, the use of genus-specific DWBD meta-means is justified.

Distribution and ecology of the predatory katydid Saga pedo (Pallas, 1771) in Croatia with the first record in the continental region

Until now, Saga pedo (Pallas, 1771) was known to occur in Croatia only in the Mediterranean biogeographical region and on the southern slopes of the Dinaric Alps in the Alpine region. Here we give the first record of the species' presence deep inside what is officially called the Alpine region and in the Peripannonian area in the Continental region of the country. Along with all known specimens and observation records, our results represent the updated distribution of S. pedo in Croatia. Some notes on ecology, field observations, and discussion about habitat preferences are also given.

Birds and Natura 2000: a review of the scientific literature

Summary The Natura 2000 network, the pillar of biodiversity conservation in Europe, still shows some knowledge gaps after almost 30 years since its implementation. As birds are a taxonomic group that is underrepresented in the literature related to Natura 2000 compared to their importance in the EU Directives, this review investigated the characteristics of the scientific research dedicated to birds in relation to Natura 2000. This review focused on 169 peer-reviewed articles covering a period of 25 years (1995–2019). Most studies were set within single Natura 2000 site or regions within countries, and concerned terrestrial habitats, particularly wetlands. The terrestrial Mediterranean biogeographical region and marine Atlantic region had the greatest number of publications, while Spain, Italy, and France were the countries with the highest number of reviewed articles. The number of publications was correlated to Natura 2000 coverage at both country and biogeographical region level. Bird species were studied mainly at a community or single-species level and most publications studied distribution and occurrence of the bird species of interest, while very few assessed the conservation status of the species. Only a few articles set within Natura 2000 sites addressed the issues of habitat suitability for birds or the effectiveness of conservation efforts. Both Annex I and non-Annex I bird species were examined in the literature, with most species having decreasing population trends at the European scale. Future research on bird conservation and Natura 2000 should focus on marine ecosystems as well as habitats that have received less attention despite their important role in a changing future (alpine and urban types). Moreover, future studies should encompass larger spatial scales and those species for which status and trends are still not thoroughly investigated. Finally, it would be important to enhance research efforts on the conservation status and effectiveness in relation to the network.

ReptIslands: Mediterranean islands and the distribution of their reptile fauna

AbstractAimAnalyses of biogeographical patterns and macroecology of islands require large datasets reporting the occurrence of species. The Mediterranean region is a biodiversity hotspot, which hosts a large number of reptile species and has been the focus of many studies. Nevertheless, comprehensive inventories describing the features and biodiversity of these environments are lacking. We gathered a dataset summarizing data on reptile distribution on islands of the Mediterranean basin and Macaronesia, also including detailed information on the geographical features.LocationIslands from the Mediterranean Basin, the Atlantic Ocean within the Mediterranean biogeographical region, and Macaronesia (Canary and Savage Islands, Azores, Madeira and Cape Verde).Time periodPresent.TaxonReptiles (squamates and turtles).MethodsInitially, we developed a geographical database describing islands of the study region, then gathered information on reptile occurrences from 757 bibliographical sources, including atlases, published papers and the grey literature. Through a critical review of these sources, we also obtained information on the status of populations (native, island endemic or non‐native) and on the reliability of occurrence data.ResultsWe obtained basic geographical information from 1875 islands covering the whole study region and with a very broad range of geographical features. We gathered &gt;4150 records of reptile occurrence on islands, referring to 198 taxonomic units (species or species complexes); information on population status was available for 84.9% of records. Data are provided as comma‐delimited text files.Main conclusionsThe database provides a key resource for biogeographical analyses and can also serve as a backbone for conservation studies. The availability of a large database on island features can also be useful for biogeographers working on other taxonomic groups. Nevertheless, more data are required for some geographical areas, in order to ascertain the status (e.g., native vs. non‐native) of many populations and to understand the interplay between natural and human‐driven processes.

Checklist of the vascular plants of the Cantabrian Mountains

We present the first standardized list of the vascular flora of the Cantabrian Mountains, a transitional zone between the Eurosiberian and Mediterranean biogeographic regions in northwestern Spain. The study area comprises 15000 km2 divided in UTM grid cells of 10 km x 10 km, for which we revised occurrence data reported in the Spanish Plant Information System (Anthos) and the online database of Iberian and Macaronesian Vegetation (SIVIM). We used a semi-automatic procedure to standardize taxonomic concepts into a single list of names, which was further updated by expert-based revision with the support of national and regional literature. In the current version, the checklist of the Cantabrian Mountains contains 2338 native species and subspecies, from which 56 are endemic to the study area. The nomenclature of the checklist follows Euro+Med in 97% of taxa, including annotations when other criteria has been used and for taxa with uncertain status. We also provide a list of 492 non-native taxa that were erroneously reported in the study area, a list of local apomictic taxa, a phylogenetic tree linked to The Plant List, a standardized calculation of Ellenberg Ecological Indicator Values for 80% of the flora, and information about life forms, IUCN threat categories and legal protection status. Our review demonstrates how the Cantabrian mountains represent a key floristic region in southern Europe and a relevant phytogeographical hub in south-western Europe. The checklist and all related information are freely accessible in a digital repository for further uses in basic and applied research

Niche Characterization of Shrub Functional Groups along an Atlantic-Mediterranean Gradient

The identification of the factors controlling the understory species distribution and abundance is essential to understand the ecology and dynamics of natural forests and their management response. We assess the relationships between environmental gradients and shrub functional groups distribution patterns and niche characteristics in a transitional area between the Eurosiberian and Mediterranean biogeographic regions in Northern Spain. Here, 772 plots from the 3rd Spanish National Forest Inventory were used. Shrub functional groups respond to the same complex environmental gradients as trees, i.e., the north-south climatic gradient and a slope gradient. Unimodal response curves of shrub functional groups and families dominate along both gradients, providing evidence of successful functional turnover. Similar to tree species, the niche location of functionally related shrubs is close. Functional groups occupying environments with sharp contrast or transitional environments have the broadest niches, whereas those specialized functional groups occupying localized habitats showed the narrowest niches. The knowledge of shrub species distributions and niche characteristics along complex environmental gradients will improve our ability to discuss potential conservation management goals or threats due to land-use changes and future climate change.

Inocybe brijunica sp. nov., a New Ectomycorrhizal Fungus from Mediterranean Croatia Revealed by Morphology and Multilocus Phylogenetic Analysis.

A new ectomycorrhizal species was discovered during the first survey of fungal diversity at Brijuni National Park (Croatia), which consists of 14 islands and islets. The National Park is located in the Mediterranean Biogeographical Region, a prominent climate change hot-spot. Inocybe brijunica sp. nov., from sect. Hysterices (Agaricales, Inocybaceae), is described based on morphology and multilocus phylogenetic data. The holotype collection was found at the edge between grassland and Quercus ilex forest with a few planted Pinus pinea trees, on Veli Brijun Island, the largest island of the archipelago. It is easily recognized by a conspicuous orange to orange–red–brown membranaceous surface layer located at or just above the basal part of the stipe. Other distinctive features of I. brijunica are the medium brown, radially fibrillose to rimose pileus; pale to medium brown stipe with fugacious cortina; relatively small, amygdaliform to phaseoliform, and smooth basidiospores, measuring ca. 6.5–9 × 4–5.5 µm; thick-walled, utriform, lageniform or fusiform pleurocystidia (lamprocystidia) with crystals and mostly not yellowing in alkaline solutions; cheilocystidia of two types (lamprocystidia and leptocystidia); and the presence of abundant caulocystidia only in the upper 2–3 mm of the stipe. Phylogenetic reconstruction of a concatenated dataset of the internal transcribed spacer region (ITS), the nuclear 28S rRNA gene (nrLSU), and the second largest subunit of RNA polymerase II (rpb2) resolved I. brijunica and I. glabripes as sister species.

Integrative effects of increasing aridity and biotic cover on soil attributes and functioning in coastal dune ecosystems

Climate change-driven increases in aridity will lead to dryland expansion worldwide. In the Atlantic and Mediterranean biogeographic regions, coastal dunes are priority conservation areas highly sensitive to aridification where plants and biological soil crusts may play a key role maintaining ecosystem services. However, we still need further insights into the balance between the effects of increasing aridity and the influence of local vegetation on the soil attributes and functioning of these systems, particularly in transitional areas between humid and arid climatic zones. We sampled 24 dune systems distributed along a natural climate gradient including humid, dry-subhumid and arid environments in the Atlantic coastline of the Iberian Peninsula and investigated (i) how aridity drives the vegetation community structure, soil biotic and abiotic properties and functions in dune ecosystems at a regional scale; and (ii) to what extent soil attributes differ locally under diverse surface microsites (i.e. plants, biocrust and bare soil). Increasing aridity in coastal dunes decreased total biotic cover and favoured the formation of shrub-dominated patches. Vegetation shifts were accompanied by declines in soil microbial diversity, organic matter, nutrient contents and reduced rates of N mineralization. Soil bacterial communities were more sensitive to aridity than fungal communities. Microsites were essential regulators of soil attributes, and their effects were dependent on the degree of aridity. In drylands, shrub microsites were associated to higher soil organic C, microbial (bacterial and fungal) abundance, fungal diversity and potential heterotrophic respiration than bare microsites, likely due to enhanced litter and sediment redistribution. However, at humid and transition systems, microsites controlled soil N pools and microbial diversity, suggesting tight linkages between vegetation patches and soil microorganisms responsible for N availability. These findings provide evidence of the strong negative impacts of aridification on vegetation attributes and nutrient cycling in coastal dunes and highlight the role of the biotic cover in preserving soil fertility, microbial diversity and functioning, particularly in the most arid sites.

Biodiversity and sequestration potentials of the peat soils in the area of Livanjsko field

Livanjsko field is one of the largest karst fields in the subtropical climate zone in the world. According to its geographical position, this field has a number of specific natural features, among which its biodiversity is especially significant, which arose in specific geological and hydro-morphological conditions in its northern, central and southern part. One of the special natural features of this area is the peat pedological substrate which was formed in the conditions of specific paleogeographic conditions that existed in the wider Mediterranean biogeographical region during the Neogene. However, over the last 50 years, various negative anthropogenic pressures have been registered that have a very negative impact on the overall natural heritage of this Ramsar site. The paper investigates the elements of the diversity of recent flora and field vegetation. Special emphasis in these researches was placed on the sequestration potentials of peat pedosubstrate formed in the northern and southern part of Livanjsko field.

Estimación de la fenología de la vegetación a partir de imágenes de satélite: el caso de la península ibérica e islas Baleares (2001-2017)

Phenological dynamics of vegetation is considered as an important biological indicator for understanding the functioning of terrestrial ecosystems. Land surface phenology (LSP), the study of vegetation phenology from time series of vegetation indices (IV), has provided a comprehensive overview of ecosystem dynamics. Iberian Peninsula is one of the regions with the greatest diversity of ecosystems in European continent. It is therefore an excellent study area for monitoring phenological dynamics of vegetation. The aim of this study is to analyse the spatial variability of the phenology of the vegetation of the Iberian Peninsula and Balearic Islands for the period 2001-2017. NDVI (Normalized Difference Vegetation Index) time series were generated from the surface reflectance product MOD09Q1 at a spatial resolution of 250 meters and with a composite period of 8 days. Atmospheric disturbances and noise were reduced using a Savitzky-Golay smoothing filter. Different phenological metrics or phenometrics were extracted using a threshold-based method. Results showed the existence of a different behaviour between spring and autumn phenophases in the Atlantic and Mediterranean biogeographic regions. The Mediterranean mountainous areas showed a similar phenological behaviour to the Atlantic vegetation. Biogeographic regions showed an internal variability, which may be derived from the different behaviour of land covers (e.g., natural vegetation vs. crops).

The spread of exotic fish species in Italian rivers and their effect on native fish fauna since 1990

ABSTRACT The introduction of exotic fish species into Italian river systems presents an additional threat to freshwater native fish species, a wildlife group already under conservation pressure from myriad other anthropogenic factors. Few large-scale and long-term monitoring programmes exist that adequately describe the impact of exotic fish species on native fish. To fill this gap, we analysed the bulk of available data (1985–2014) on fish collected at a national level within the BioFresh Project with the aim of investigating the effects of human-introduced exotic fish species on native species. The results showed that both the Continental and Mediterranean biogeographic regions are home to fish communities which, in conservation terms, are a cause for concern, while Alpine Regions are less so. Generally, the richness of exotic species is still growing in Italy, with about 50% of them having a positive trend while native species’ trends are in the opposite direction – that is, the spread of many exotic species is positively correlated with the decline in many co-occurring native species. Key policy insights Worrying increase in the richness of exotic species between the 1985 and the 2014. A large segment of the current exotic fish contingent is self-sustaining. Common bream, Black bullhead, Goldfish, Largemouth bass, Rainbow trout, Roach, Pike perch and European catfish negatively affect the presence probability of at least 50% of co-occurring native species over time. The restoration of habitat characteristics and native fish assemblages as well as more rigorous controls during population reinforcement for recreational fishing are needed to prevent or counteract the further spread of exotic fishes.

Contribution of free satellite time-series images to mapping plant communities in the Mediterranean Natura 2000 site: the example of Biguglia Pond in Corse (France)

Mapping plant communities, which is essential to assess the conservation status of natural habitats, is currently based mainly on time-consuming field surveys without the use of satellite data. However, free image time-series with high spatial and temporal resolution have been available since 2015. This study assessed the contribution of Sentinel-2 time-series images to mapping the spatial distribution of 18 plant communities within a Natura 2000 site (1978 ha) located on the Mediterranean biogeographical region (Corsica, France). The method was based on random forest modeling of six Sentinel-2 images acquired from 26 February to 24 October 2017, which were calibrated and validated using a field vegetation map. The results showed that the 18 plant communities were modeled correctly, with 72% overall accuracy. The uncertainty map associated with the model indicated areas that required additional field observations.

Deadwood stocks in south-western European forests: Ecological patterns and large scale assessments

Forest deadwood is a relevant factor in the provision of ecosystem services (forest biodiversity, carbon sequestration, recreational and aesthetic values), but it also influences the risk and impact of forest perturbations. Hence, reliable estimations are urgently need in the lack of detailed information in Mediterranean forests at large scales. In this study we provide, for the first time, national-level estimations for Spain based on the information from the Spanish National Forest Inventory (38,945 plots). In addition, we compare and validate two approaches for estimating deadwood stocks where data is lacking; the first of these being a modelling approach based on stand, climatic and physiographical variables, and the other considers the ratio between deadwood and living biomass. We also examine the different patterns stock across forest types in four biogeographical regions according to a broad-spectrum of species groups and forests with different degrees of anthropogenic influence. The degrees are based on levels of protection and naturalness categories.The modelling approach provides more robust deadwood estimates and better predictive capacity than the ratio approach. Alpine (6.09 Mg.ha−1) and Atlantic (3.53 Mg.ha−1) bioregion forests store significantly higher mean deadwood biomass stocks than Macaronesian and Mediterranean forests. However, the share of deadwood in relation to the total biomass stock is greater in Mediterranean biogeographical region. As regards species groups, the mean deadwood stock of mixed forests doubled the stocks found in conifer and broadleaved dominated forests. We also found significant differences in deadwood biomass stocks between forests with different levels of anthropogenic protection. However, forest types with intensive forest management had contrasting figures for deadwood stock.The mean values obtained at national level according to forest type, bioregion and degree of anthropogenic influence, provide baseline information for carbon accounting as well as for other forest policy planning and management strategies.

Conservation status of Italian coastal dune habitats in the light of the 4th Monitoring Report (92/43/EEC Habitats Directive)

Coastal dunes are among habitats with the worst conservation status on a global, European and national scale. Monitoring and reporting are of strategic importance to determine the effectiveness of the implementation of Habitats Directive and to preserve the unique biodiversity heritage of the Italian dunes. In this study we show main results of the 4th National Report with specific reference to the macro-habitat “Coastal Sand Dunes and Inland Dunes”, highlighting its updated current conservation status at the national and Biogeographical level. A comprehensive Working Group of territorial experts collected, updated, validated and integrated the data available for 11 Annex I Habitats, distributed in the Alpine, Continental and Mediterranean Biogeographical Regions. The conservation status was evaluated through the following criteria: geographic range, surface area, structure, functions, pressures, threats, conservation measures and prospects. Results highlighted the dramatically bad conservation status of Italian dune Habitats: the overall assessment reported 88% of habitats in bad conservation status and the remaining 12% is in inadequate conditions. Results showed a generalised threat and a worrying conservation status both on herbaceous and wooded communities, in particular in some relevant habitats, such as the shifting dunes. Main pressures and threats were linked to residential, commercial and industrial activities, as well as alien species. Although some of the changes in distribution and trends are probably deriving from more accurate and updated data, the alarming conservation status of Italian sand dunes requires a better knowledge of pressures and threats for further management actions and monitoring plans, inside and outside protected areas.

Syntaxonomy of the Robinia pseudoacacia communities in the central peri-adriatic sector of the Italian peninsula

This study presents the results of a floristic vegetational study on Robinia pseudoacacia neoformation forests in the peri-Adriatic sector of central Italy. This has allowed the characterization of these coenoses at the ecological, biogeographic, syntaxonomic and landscape levels. These currently represent the southernmost syntaxa of the Robinietea class described for the Italian peninsula, and the first syntaxonomic contribution of this class in Europe for the Mediterranean biogeographical region. We propose here the new alliance Lauro nobilis–Robinion pseudoacaciae of the order Chelidonio–Robinietalia pseudoacaciae and class Robinietea, with two new associations: Melisso altissimae–Robinietum pseudoacaciae and Rubio peregrinae–Robinietum pseudoacaciae. The new alliance Lauro nobilis–Robinion pseudoacaciae (typus: Melisso altissimae–Robinietum pseudoacaciae) brings together neoformation forests and pre-forest dominated by R. pseudoacacia in those territories with a Mediterranean macroclimate of the peri-Adriatic sector of central Italy. The optimum is found for the alluvial plain and low-slope morphologies, on soils that are moist and rich in organic matter and in areas with anthropic disturbance. On the basis of comparisons with the European context, the alliance Bryonio–Robinion described for the temperate territories of northern Italy is here validated.

Human-environmental drivers and impacts of the globally extreme 2017 Chilean fires.

In January 2017, hundreds of fires in Mediterranean Chile burnt more than 5000km2, an area nearly 14 times the 40-year mean. We contextualize these fires in terms of estimates of global fire intensity using MODIS satellite record, and provide an overview of the climatic factors and recent changes in land use that led to the active fire season and estimate the impact of fire emissions to human health. The primary fire activity in late January coincided with extreme fire weather conditions including all-time (1979-2017) daily records for the Fire Weather Index (FWI) and maximum temperature, producing some of the most energetically intense fire events on Earth in the last 15-years. Fire activity was further enabled by a warm moist growing season in 2016 that interrupted an intense drought that started in 2010. The land cover in this region had been extensively modified, with less than 20% of the original native vegetation remaining, and extensive plantations of highly flammable exotic Pinus and Eucalyptus species established since the 1970s. These plantations were disproportionally burnt (44% of the burned area) in 2017, and associated with the highest fire severities, as part of an increasing trend of fire extent in plantations over the past three decades. Smoke from the fires exposed over 9.5 million people to increased concentrations of particulate air pollution, causing an estimated 76 premature deaths and 209 additional admissions to hospital for respiratory and cardiovascular conditions. This study highlights that Mediterranean biogeographic regions with expansive Pinus and Eucalyptus plantations and associated rural depopulation are vulnerable to intense wildfires with wide ranging social, economic, and environmental impacts, which are likely to become more frequent due to longer and more extreme wildfire seasons.

Range limits in sympatric cryptic species: a case study in Tetramorium pavement ants (Hymenoptera: Formicidae) across a biogeographical boundary

Abstract In the context of climate changes, factors that determine the distribution patterns of European species of the ubiquitous ant genus Tetramorium were investigated. The study took place along a steep North‐South climatic gradient across the boundary between the European Continental and Mediterranean biogeographical regions spanning 460 km along the Rhône valley, France. Ants from 1690 Tetramorium colonies were collected in 19 sampling zones. Species were identified using an integrative approach based on a two‐step process combining nuclear DNA (14 microsatellite markers), morphological examination and mitochondrial DNA cytochrome oxidase I sequencing. The impact of climate on species distribution patterns was tested using bioclimatic variables. Species discrimination was successful, despite a complex situation with cryptic species, inter‐specific hybridisation and uneven sampling across species. Our results showed a strong effect of latitude, temperature and rainfall on the distribution of three of four species. Tetramorium semilaeve was found only south of the boundary, in warmer and dryer sites; Tetramorium caespitum extended north and 70 km south of the boundary and favoured colder sites with strong seasonal variation. Tetramorium immigrans was absent from the northernmost sampling zones and favoured warmer and wetter sites. Tetramorium moravicum was mostly found close to the boundary, but without significant climatic preferences. The fundamental role of climate as a factor limiting the ranges of these species at a major biogeographical boundary is confirmed. Monitoring range limits of these strongly climate‐dependant species may offer exciting insights on the impact of climate changes on species distributions.