Intraspecific differences in the response to drying of Quercus ithaburensis acorns

In this study, we investigated the germination behavior, and the differences in desiccation sensitivity and water uptake (WU), of the acorns of the two subspecies of Quercus ithaburensis, inhabiting different ecological niches. Sensitivity of acorns to drying was assessed by subjecting them to several desiccation treatments. The results showed that acorn water loss due to desiccation follows an almost linear pattern for the subspecies macrolepis, while in the case of subspecies ithaburensis, it follows a negative exponential model. Accordingly, the germination behavior was found highly dependent on water loss for both subspecies. The low acorn water content (15%) achieved after 15 days of drying was crucial for the ssp. macrolepis, while it had no effect on seed viability in ssp ithaburensis, that needed a subtle further water loss to reduce its germinability (i.e. <14.5% mc). Our results suggest that intraspecific differences in seed responses to drying may be due to different adaptation to survive drought after dispersal and contribute to explain the ability of ssp. ithaburensis to grow in the hottest and driest Mediterranean bioclimates. Despite being recalcitrant, the ssp. ithaburensis can be considered as one of the most tolerant oaks to desiccation worldwide.     

Influence of cattle grazing on the density of oak seedlings and saplings in a Tabor oak forest in Israel

The effects of cattle grazing on the density of seedlings and saplings in a Tabor oak forest (Quercus ithaburensis subsp. ithaburensis) are investigated. The Tabor oak forest studied is located in a Nature Reserve in the Mediterranean region of Israel. Cattle graze at a stocking density of 0.71 head/ha for 6 months a year. The cattle grazing in the Nature Reserve is a beneficial management measure because it enhances plant species richness and reduces shrub encroachment.The impact of grazing on the densities of seedlings and young saplings was quantified in 46 large sampling plots (333 m² each) distributed over two experimental sites; the first being used as a rangeland for decades while the second is a forest patch totally free from grazing. The density and the height of Tabor oak individuals in each sampling plot were recorded. Four height categories were distinguished with a special focus on young seedlings (<0.15 m), established seedlings and young saplings (0.15 m–1 m).The density of seedlings and young sapling in the grazed Tabor oak forest were, respectively, 61% to 67% lower than in the ungrazed treatment. Implications on the continuity of the entire Tabor oak forest ecosystem are discussed. Three management measures that enable to prevent a decrease in young oak densities are proposed – reduction of stocking rate, deferment of the commencement of grazing, and fencing young seedlings.     

The role of niche divergence and phenotypic adaptation in promoting lineage diversification in the Sage Sparrow (Artemisiospiza belli,Aves: Emberizidae)

Niche divergence or conservatism and phenotypic adaptation are important in lineage diversification. We used mitochondrial DNA (mtDNA), morphology and ecological niche models to examine these processes in three subspecies of Sage Sparrow (Artemisiospiza belli belli, A. b. canescens and A. b. nevadensis) that breed in bioclimatically diverse ecoregions in western North America. Overall, mtDNA and morphology are congruent with subspecies, ecoregion and bioclimatic niche. Niche divergence, rather than niche conservatism, accompanied by phenotypic adaptation, is associated with lineage diversification between subspecies. This diversification has occurred with and without physical barriers or accompanying genetic divergence. Populations of A. b. canescens are divided by a montane barrier into two bioclimatic regions (San Joaquin Valley, Mojave Desert), where they are indistinguishable phenotypically, but show distinctive genetic patterns. Although there is no physical barrier between A. b. canescens in the San Joaquin Valley and A. b. belli in the Coast Ranges, these populations occupy different bioclimatic niches and are phenotypically, but not genetically, diagnosable. Niche overlap is greatest between A. b. canescens from the Mojave Desert and A. b. nevadensis from the Great Basin, yet these subspecies maintain distinctive phenotypes and mtDNA, even in local secondary contact and sympatry. Palaeoclimatic niche models for the Last Glacial Maximum (c. 21 000 bp ) and the Last Interglacial (c. 120 000 bp ) suggest that ecoregionally distinct populations of Artemisiospiza belli experienced different Pleistocene range fluctuations and glacial refugia, with temporal niche conservatism. Populations probably reached their current distributions as favourable climates and habitats expanded after the last glaciation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ??, ??–??.     

A palynological study of the Acheulian site of Gesher Benot Ya’aqov, Israel

The results are discussed of the palynological (pollen-analytical) examination of a sediment section in the Hula Valley of northern Israel, with evidence of Acheulian occupation dated to 700,000–800,000 b.p. In general there is a fair agreement between the palynological data and the wood remains identified from the site, but there are also discrepancies, some of which can be explained and others not. Although relatively well represented in the pollen record, Pinus (pine) most probably did not occur in the Hula area. Some pollen types are thought to have been carried in from hundreds of kilometres away (long-distance transport). Together the pollen and wood evidence suggests that Quercus ithaburensis–Pistacia atlantica (Tabor oak–Atlantic terebinth) woodland (open forest) was found in the Hula Valley (other than the lake and marshes) and on the lower reaches of the mountains flanking the valley on both sides. In addition to deciduous Tabor oak, evergreen Kermes oak (Quercus calliprinos) must have been an important component of this woodland. Wild olive (Olea europaea var. oleaster) may also have been quite common here. The suggestion of open forest, with fairly widely spaced trees, is based upon the high non-arboreal pollen frequencies and indicates fairly dry climatic conditions. Various stream-bank trees and shrubs are represented in the pollen and/or wood records, such as Fraxinus (ash), Ulmus (elm), Salix (willow) and Platanus (plane tree). During the period represented by the upper section of the pollen diagram, Cedrus (cedar) must have reached the Hula area, indicating increased humidity. In the steppe-like field layer (undergrowth of the woodland) grasses (Gramineae) must have played a prominent role in addition to a great number of other species. In particular Compositae and Umbelliferae include a large variety of species (many different pollen types). Two Chenopodiaceae maxima, coinciding with Gramineae minima, are thought to be indicative of periods of increased climatic dryness. The local lake and marsh vegetation is fairly well represented in the pollen record, but interpretation in terms of vegetation succession is only possible to some degree. Mention is made here of Trapa natans (water chestnut), the nuts of which were consumed by the Acheulian inhabitants. Sytze Bottema: Deceased in 2005.     

Wood remains from Tel Nami,a middle bronze IIa and late bronze IIb port,local exploitation of trees and levantine cedar trade

Thirteen Middle Bronze Age IIa and four Late Bronze Age IIb (ca. 1950-1750 B.C. and thirteenth century, B.C., respectively)pieces of charcoal or water logged wood were found in the recent excavations of Tel Nami, a small port on the coast near Mount Carmel, Israel. These includedCedrus libani (cedar of Lebanon) (three samples), and local tree species that still grow today in the vicinity of the site—Pinus halepensis (Aleppo pine) (one sample),Olea europaea (olive tree) (five samples),Quercus calliprinos (kermes oak) (three samples),Quercus ithaburensis (Mt. Tabor oak) (four samples), andQuercus sp. (one sample). The discovery of Cedrus libani in a Middle Bronze Age IIa port is one of the earliest published examples of cedar wood from Israel. Together with other artifactual evidence for maritime trade from Tel Nami, this find suggests that a maritime trade in cedar wood existed along the Levantine coast.     

Molecular analysis of the recently described lizardfish Saurida lessepsianus (Synodontidae) from the Red Sea and the Mediterranean,with remarks on its phylogeny and genetic bottleneck effect

The opening of the Suez Canal in 1869 led to a massive influx of Red Sea species that invaded the Mediterranean; this was termed ‘Lessepsian migration'. Among these species was a species of lizardfish, identified by some authors as Saurida undosquamis and by others as S. macrolepis. Recently, the Red Sea and the Mediterranean populations were described according to external characteristics as a unique taxon, Saurida lessepsianus. Our molecular study confirms this finding and determines that all previous records of S. undosquamis and S. macrolepis in the Red Sea and the Mediterranean are misidentifications of S. lessepsianus. The Mediterranean population of S. lessepsianus exhibits a lower genetic variability than that of the Red Sea population, suggesting a bottleneck effect.     

Niche overlap of mountain hare subspecies and the vulnerability of their ranges to invasion by the European hare; the (bad) luck of the Irish

Niche conservatism is the tendency of related species to retain ancestral tolerances after geographic separation. We used Ecological Niche Modelling and Principal Components Analysis of bioclimatic and habitat variables to describe the extent of the species niche, and degrees of bioclimatic–habitat niche conservatism within the mountain hare (L. timidus) clade. Mountain hare niche space was contrasted with that of the European hare (L. europaeus), to shed light on species interactions in contact zones throughout Europe. All five subspecies of mountain hare had quantifiably distinct niches. Fennoscandian (L.t. sylvaticus, L.t. timidus) and highland (L.t. scoticus, L.t. varronis) subspecies, however, were most similar, exhibiting greatest apparent niche conservatism. They inhabit tundra, boreal forest and uplands, and, hence are presumed most similar to the ancestral form. The Irish hare was distinct, being consistently distinguished from other mountain hares in both 2D and nth dimensional (4D) niche space. The ecological distinctiveness of the Irish hare provides further evidence that it is an Evolutionarily Significant Unit, particularly vulnerable to displacement by introduced European hares with which it competes and hybridises. Projections under global climate change suggest that, by 2070, bioclimatic space for invasive European hares in Ireland will expand (by 79%) but contract for endemic Irish hares (by 75%), further facilitating their replacement. The near complete species replacement of the heath hare (L.t. sylvaticus) in southern Sweden, where the European hare has also been introduced, may suggest a similar fate may be in store for the Irish hare.     

Variability of lichen diversity in a climatically heterogeneous area (Liguria,NW Italy)

Abstract:The influence of environmental variables on epiphytic lichens in Liguria (NW Italy) was examined using two complementary approaches. Firstly, the variability of lichen vegetation in relation to environmental variables was investigated. Secondly, the variability of Lichen Biodiversity (LB) counts, used in biomonitoring studies, was analysed in relation to bioclimatic areas. Geomorphology strongly affects lichen vegetation. The coastal mountain ridge and the Tyrrhenian-Po valley watershed limit the distribution range of three different communities: a Parmelion community with a high frequency of coastal suboceanic species, a Parmelion community rich in oak wood species and the Parmelietum acetabuli association, situated beyond the Po Valley watershed. Substantial differences in the distribution of lichen communities related to a climatic gradient (from humid Mediterranean to dry sub-Mediterranean regions) are not matched by corresponding statistically significant differences in LB counts. More accurate studies are necessary to define homogeneous bioclimatic areas, in which LB values can be compared for biomonitoring purposes.     

Arundo micrantha,a new reed species for Italy,threatened in the freshwater habitat by the congeneric invasive A. donax

Arundo micrantha Lam., a reed species from southern Mediterranean area, has found in Sardinia. Its presence represents the first record for Italy and the third one for western Europe. Investigations on distribution and ecology of the Sardinian population have been carried out, with special focusing on synecology of the species. A. micrantha has found in 40 localities mainly distributed along temporary streams and permanent rivers in the central and southern part of the island. Most of Sardinian populations occurs on alluvial soils in Thermomediterranean bioclimatic context. The autonomy of Sardinian phytocoenoses was characterized with the definition of exclusive floristic taxa, biological and chorological elements, and syndinamic relationships with other assemblages. Comparing the community with other reed beds from the Mediterranean basin, a marked floristic differentiation arose between the phytocoenoses characterized by autochthonous Arundo species and those dominated by the invasive Arundo donax. Finally, management activities are proposed to ensure the conservation of this threatened autochthonous plant community in freshwater habitat.     

Bioclimatic evaluation of geographical range in Fragaria (Rosaceae): consequences of variation in breeding system,ploidy and species age

The evaluation of the intrinsic and extrinsic forces that determine geographical range sizes and niche breadth is key to the understanding of species distributions and for informing the conservation of biodiversity. Fragaria (Rosaceae) contains the economically important cultivated strawberry (Fragaria × ananassa subsp. ananassa) and numerous wild species. Using georeferenced species records and global bioclimatic data, we describe the bioclimatic niches for 21 Fragaria spp. and investigate the relationship between their niches and geographical range size, breeding system, ploidy and time since divergence. We found no evidence of phylogenetic signal for bioclimatic niches. There was also no relationship between ploidy and geographical or bioclimatic range area, but geographical range area was significantly greater for species that were capable of self‐fertilization. In addition, we found a significant decelerating relationship between species age and geographical range area. Overall, our results suggest that Fragaria spp., although similar in morphology and life history, show high levels of divergence in bioclimatic niches and significant over‐dispersion along some bioclimatic gradients, suggesting evolutionary lability in physiology and climate tolerance. As a consequence, wild species will remain a valuable resource for cultivated strawberry sustainability, especially under changing future climate. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176 , 99–114.     

Forecasting the start of <Emphasis Type="Italic">Quercus</Emphasis> pollen season using several methods – the evaluation of their efficiency

Forecasting the time when the atmospheric pollen season of allergenic plants begins is particularly important for doctors and their patients. The aim of this paper is to determine whether it is possible to forecast the start of the oak (Quercus) pollen season in Rzeszów, Poland. In the elaboration of the most effective model, various forecasting techniques were tested: growth degree days (GDD°C); meteorological factors; bioclimatic factors; and indicator taxon. The aerobiological monitoring was carried out in 1997–2005 and 2007 in Rzeszów (SE Poland). In the presented investigation, three methods defining the start of the Quercus pollen season were selected on the basis of accumulated sums of pollen or the constant occurrence of pollen grains in air. Despite the application of different combinations of GDD°C methods and threshold temperatures, the correlation coefficients between the expected and obtained values were low. In some cases, however, they proved highly effective for the test years (2005, 2007) with the accuracy of a few days. For GDD°C methods, the best threshold temperatures range between 5 and 6°C. Models based on bioclimatic indices and meteorological variables were not satisfactory. On the basic of the 10 years of results, the method of indicator species were good for forecast the start of oak pollen season. Birch was the best indicator taxa.     

Seedling growth and morphology of three oak species along field resource gradients and seed mass variation: a seedling age‐dependent response

Question: What is the relative importance of seed mass and abiotic factors in species‐specific seedling growth and morphology during the first and the second growing season? How do oak species respond along gradients of these factors? Location: Mediterranean oak forest in southern Spain. Methods: We analysed seedling growth components and morphology of three co‐occurring Quercus species (two deciduous and one evergreen). Oak seeds with a wide variety of sizes were sown along broad gradients of abiotic conditions. Intra‐ and inter‐specific differences were evaluated by calibrating maximum likelihood estimators of seedling growth during the first two years of life. Results: We found multiple resources and conditions affecting seedling morphology and biomass allocation. However, the integrative variables of seedling growth – total aboveground biomass and relative growth rate (RGR) – were affected by two main factors: seed mass and light conditions. The relative contribution of these two factors depended strongly on seedling age. Seed mass explained most of the growth and morphological variables during the first year, while light conditions were the best predictor in the second growing season. In contrast, soil factors did not play an important role in seedling growth. We found some evidence of regeneration niche partitioning between oak species along the light gradient, a reflection of their distribution patterns as adults at the study site. Conclusions: We conclude that inter‐specific differences in seedling growth, arising from seed size variability and microsite heterogeneity, could be of paramount importance in oak species niche segregation, driving stand dynamics and composition along environmental gradients.     

Aedes species in treeholes and fruit husks between dry and wet seasons in southeastern Senegal

During the dry season in February, 2010 and the wet season in September, 2011 we sampled mosquito larvae and eggs from treeholes of seven native hardwood species and the husks of Saba senegalensis in 18 sites in the PK‐10 forest in southeastern Senegal. Larvae were reared to adults for species identification. In the dry season, we recovered 408 Aedes mosquitoes belonging to seven species. Aedes aegypti s.l. comprised 42.4% of the collection, followed by Ae. unilineatus (39%). In contrast to reports from East Africa, both Ae. aegypti aegypti and Ae. aegypti formosus were recovered, suggesting that both subspecies survive the dry season in natural larval habitats in West Africa. In the wet season, 455 mosquitoes were collected but 310 (68.1%) were the facultatively predaceous mosquito Eretmapodites chrysogaster. The remaining 145 mosquitoes consisted of ten Aedes species. Aedes aegypti s.l. comprised 55.1% of these, followed by Ae. apicoargenteus (15.2%) and Ae. cozi (11.7%). Similar to East Africa, most (90%) of Ae. aegypti s.l. in the wet season were subspecies formosus.     

Plant functional identity as the predictor of carbon storage in semi-arid ecosystems

Background: There is an increasing consensus that ecosystem processes are governed by functional identity and trait variation rather than species richness. Despite its importance, the relative effect of relevant functional traits for carbon storage has remained mostly untested in different bioclimatic regions.

Aims: In this study, different components of functional diversity such as community-weighted means of trait values (CWM), functional trait diversity (Rao’s quadratic diversity), functional richness (FRi), functional evenness (FEv) and functional divergence (FDiv) were used to associate carbon content of above-ground biomass, litter and soil in four bioclimatic regions including warm and cold-steppe, semi-steppe rangelands and oak dry forest in the south-west of Iran.

Methods: Several key important traits highly associated with carbon storage including specific leaf area (SLA), height (H), leaf dry matter content, leaf nitrogen and phosphorus content (LNC and LPC), leaf longevity, wood specific gravity and life form were determined to quantify single and multiple traits that contribute to different components of plant functional diversity.

Results: The results showed that CWM of H, Chamaephyte life form, LNC and LPC were among the most important aspects of functional diversity that positively predicted carbon storage in above-ground biomass and soil. We also observed the negative association of carbon storage with FEv of LNC, Rao of LNC and FEv of multiple traits in the rangelands and the negative association of carbon storage with FDiv of SLA in the forest.

Conclusions: Our results indicate that different components of functional diversity are essential for a mechanistic understanding of the role of plant diversity for carbon storage. The negative associations between FDiv and FEv and carbon storage do not provide support for the complementarity niche hypothesis. Our results suggest that in the more functionally diverse ecosystems dominated by functionally important species with key traits, the so-called functional identity does indeed promote carbon storage, at least in these semi-arid ecosystems.     

Predicting the current distribution and potential spread of the exotic grass Eragrostis plana Nees in South America and identifying a bioclimatic niche shift during invasion

Eragrostis plana (Poaceae) is a perennial grass introduced from South Africa to the state of Rio Grande do Sul in southern Brazil. Currently, it is considered an invasive grass in several regions of the world, including South America, where it has caused negative ecological and socio‐economic impacts. Ecological niche models, using bioclimatic variables, are often used to predict the potential distribution of invasive species. In this study we prepared two bioclimatic models for E. plana using the Genetic Algorithm for Rule‐set Production, the first based on data from its native region (South Africa) and the second on data from both the native and invaded (South America) regions. We then projected each model onto South America to identify regions vulnerable to invasion by the species, and compared our results with available records of the species in South America. Finally, we explored the model's predictions for the existence of a bioclimatic niche shift during the invasion process of E. plana in South America, using multivariate statistical analysis. The model created with native distribution data was only able to predict (with highly suitable habitat) the region of introduction of E. plana in South America. However, the current distribution, as well as the region of introduction of the species, was reliably predicted by the model created with data from both native and invaded regions. Our multivariate analysis supports a hypothesis of bioclimatic niche shift during the invasion process of E. plana in South America.     

Climate and vegetation at the Eurosiberian-Mediterranean boundary in the Iberian Peninsula

Abstract. The Northern Iberian Peninsula is dominated by various types of vegetation from deciduous oak and ash to evergreen oak woodlands. A recent vegetation map of Spain portrays vegetation series which are characterized in terms of their phytogeographic region or bioclimatic (altitudinal) belt. The aim of this paper is to determine whether the areas comprised by both phytogeographic regions (Eurosiberian and Mediterranean) in the study area, as established from the phytogeographic characterization of the vegetation, can be discriminated by climatic variables using multivariate methods, and to compare these with other conventional approaches. In addition, bioclimatic (altitudinal) belts and the main vegetation types were tested for discrimination by climatic variables. Conventional climatic criteria as well as discriminant and principal component analysis were applied to climatic data from 205 meteorological stations for which vegetation information had been taken from the vegetation map. Conventional criteria are good predictors of the phytogeographic division (Mediterranean and Eurosiberian regions) in the study area. Results were improved by multiple discriminant analysis based on climatic data of the dry period of the year (June to September). Both regions in the study area can be predicted with over 95 % accuracy. Using the same multivariate procedure and temperature data the bioclimatic (altitudinal) belts of the study area can be predicted with over 90 % accuracy. The main vegetation groups of the study area can also be predicted with over 80 % accuracy. Ordination analysis supported the results of the discriminant analysis. Empirical models have been generated to predict the phytogeographic- and belt character of any station in the area. The significance of the various periods of the year for discriminating regions and belts is evaluated. The responsiveness to climatic events during the year may be region specific. This study confirms the strong relationship between climate and vegetation in the Northern Iberian Peninsula, particularly regarding the Eurosiberian-Mediterranean boundary.     

Seasonal population and individual niche dynamics in a tetra fish in the Pantanal wetlands

In seasonal tropical regions, rainfall and/or temporary floods during the wet season generally increase the abundance and diversity of food resources to many consumers as compared to the dry season. Therefore, seasonality can affect intraspecific competition and ecological opportunity, which are two important ecological mechanisms underlying population and individual niche variations. Here, we took advantage of the strong seasonality in the Pantanal wetlands to investigate how within‐ and between‐individual diet variations relate to seasonal population niche dynamics of the tetra fish Astyanax lacustris. We quantified dietary niche using gut contents and stable isotopes. Tetras had higher gut fullness and better body condition in the wet season, suggesting that competition is more intense in the dry season. The population niche was broader in the wet season due to an increase in diet divergence between individuals, in spite of potential stronger competition in the dry season. We posit that low ecological opportunity in the dry season limits the diversifying effect of intraspecific competition, constraining population niche expansion. Our results add new insights on how seasonality affects population and individual diets, indicating that intraspecific competition and ecological opportunity interact to determine temporal niche variations in seasonal environments.     

Niche-based modelling as a tool for predicting the risk of alien plant invasions at a global scale

Predicting the probability of successful establishment of plant species by matching climatic variables has considerable potential for incorporation in early warning systems for the management of biological invasions. We select South Africa as a model source area of invasions worldwide because it is an important exporter of plant species to other parts of the world because of the huge international demand for indigenous flora from this biodiversity hotspot. We first mapped the five ecoregions that occur both in South Africa and other parts of the world, but the very coarse definition of the ecoregions led to unreliable results in terms of predicting invasible areas. We then determined the bioclimatic features of South Africa's major terrestrial biomes and projected the potential distribution of analogous areas throughout the world. This approach is much more powerful, but depends strongly on how particular biomes are defined in donor countries. Finally, we developed bioclimatic niche models for 96 plant taxa (species and subspecies) endemic to South Africa and invasive elsewhere, and projected these globally after successfully evaluating model projections specifically for three well‐known invasive species (Carpobrotus edulis, Senecio glastifolius, Vellereophyton dealbatum) in different target areas. Cumulative probabilities of climatic suitability show that high‐risk regions are spatially limited globally but that these closely match hotspots of plant biodiversity. These probabilities are significantly correlated with the number of recorded invasive species from South Africa in natural areas, emphasizing the pivotal role of climate in defining invasion potential. Accounting for potential transfer vectors (trade and tourism) significantly adds to the explanatory power of climate suitability as an index of invasibility. The close match that we found between the climatic component of the ecological habitat suitability and the current pattern of occurrence of South Africa alien species in other parts of the world is encouraging. If species' distribution data in the donor country are available, climatic niche modelling offers a powerful tool for efficient and unbiased first‐step screening. Given that eradication of an established invasive species is extremely difficult and expensive, areas identified as potential new sites should be monitored and quarantine measures should be adopted.     

Niche shift versus niche conservatism? Climatic characteristics of the native and invasive ranges of the Mediterranean house gecko (Hemidactylus turcicus)

Aim The use of ecological niche models (ENMs) to predict potential distributions of species is steadily increasing. A necessary assumption is that climatic niches are conservative, but recent findings of niche shifts during biological invasion indicate that this assumption is not always valid. Selection of predictor variables may be one reason for the observed shifts. In this paper we assess differences in climatic niches in the native and invaded ranges of the Mediterranean house gecko (Hemidactylus turcicus) in terms of commonly applied climate variables in ENMs. We analyse which variables are more conserved versus relaxed (i.e. subject to niche shift). Furthermore, we study the predictive power of different sets of climate variables. Location The Mediterranean region and North America. Methods We developed models using Maxent and various subsets of variables out of 19 bioclimatic layers including: (1) two subsets comprising almost all variables excluding only highly collinear ones; (2) two subsets with minimalistic variable sets of water availability and energy measures; (3) two subsets focused on temperature‐related parameters; (4) two subsets with precipitation‐related parameters; and (5) one subset comprising variables combining temperature and precipitation characteristics. Occurrence data from the native Mediterranean range were used to predict the potential introduced range in North America and vice versa. Degrees of niche similarity and conservatism were assessed using both Schoener's index and Hellinger distances. The significance of the results was tested using null models. Results The degree of niche similarity and conservatism varied greatly among the predictors and variable sets applied. Shifts observed in some variables could be attributed to active habitat selection while others apparently reflected background effects. Main conclusions The study was based on comprehensive occurrence data from all regions where Hemidactylus turcicus is present in Europe and North America, providing a robust foundation. Our results clearly indicate that the degree of conservatism of niches in H. turcicus largely varies among predictors and variable sets applied. Therefore, the extent of niche conservatism of variables applied should always be tested in ENMs. This has an important impact on studies of biological invasion, impacts of climate change and niche evolution.     

Distribution,bioclimatic niche and sympatry of two Erinaceidae in Tunisia

Numerous mammalian species of North Africa have an enigmatic distribution between the Mediterranean and Saharan area. In order to study the distribution of hedgehogs in Tunisia, field data were collected from several protected areas and various natural and peri-urban environments during 4 years 2015–2018 covering the all bioclimatic zones present in the country. The present work provides a detailed geographical and ecological distribution of hedgehogs with a total of 168 occurrence data of Atelerix algirus and Paraechinus aethiopicus. Atelerix algirus showed a wide distribution range from north to south being absent only in the extreme Saharan environment. Paraechinus aethiopicus has been recorded in the centre and the south with a specialisation in the arid and Saharan environment. A parapatry distribution is also shown with a sympatric area between arid and Saharan bioclimates. Our results improve knowledge of the bioclimatic niche and habitat characteristic of these taxa not clearly defined in previous research. The presence of the two hedgehogs on Djerba Island (A. algirus and P. aethiopicus) is also confirmed.