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Comparing genetic diversity, genetic differentiation, and performance between native and nonnative populations has advanced our knowledge of contemporary evolution and its ecological consequences. However, such between-range comparisons can be complicated by high among-population variation within native and nonnative ranges. For example, native vs. nonnative comparisons between small and non-representative subsets of populations for species with very large distributions have the potential to mislead because they may not sufficiently account for within-range adaptation to climatic conditions, and demographic history that may lead to non-adaptive evolution. We used the cosmopolitan weed Conyza canadensis to study the interplay of adaptive and demographic processes across, to our knowledge, the broadest climatic gradient yet investigated in this context. To examine the distribution of genetic diversity, we genotyped 26 native and 26 nonnative populations at 12 microsatellite loci. Furthermore, we recorded performance traits for 12 native and 13 nonnative populations in the field and in the common garden. To analyze how performance was related to range and/or climate, we fit pedigree mixed-effects models. These models weighed the population random effect for co-ancestry to account for the influence of demographic history on phenotypic among-population differentiation. Genetic diversity was very low, selfing rates were very high, and both were comparable between native and nonnative ranges. Nonnative populations out-performed native populations in the field. However, our most salient result was that both neutral genetic differentiation and common garden performance were far more correlated with the climatic conditions from which populations originated than native vs. nonnative range affiliation. Including co-ancestry of our populations in our models greatly increased explained variance and our ability to detect significant main effects for among-population variation in performance. High propagule pressure and high selfing rates, in concert with the ability to adapt rapidly to climatic gradients, may have facilitated the global success of this weed. Neither native nor nonnative populations were homogeneous groups but responded comparably to similar environments in each range. We suggest that studies of contemporary evolution should consider widely distributed and genotyped populations to disentangle native vs. nonnative range effects from varying adaptive processes within ranges and from potentially confounding effects of demographic history.

Anonychomyrma is a dolichoderine ant genus of cool-temperate Gondwanan origin with a current distribution that extends from the north of southern Australia into the Australasian tropics. Despite its abundance and ecological dominance, little is known of its species diversity and distribution throughout its range. Here, we describe the diversity and distribution of Anonychomyrma in the Australian Wet Tropics bioregion, where only two of the many putative species are described. We hypothesise that the genus in tropical Australia retains a preference for cool wet rainforests reminiscent of the Gondwanan forests that once dominated Australia, but now only exist in upland habitats of the Wet Tropics. Our study was based on extensive recent surveys across five subregions and along elevation and vertical (arboreal) gradients. We integrated genetic (CO1) data with morphology to recognise 22 species among our samples, 20 of which appeared to be undescribed. As predicted, diversity and endemism were concentrated in uplands above 900 m a.s.l. Distribution modelling of the nine commonest species identified maximum temperature of the warmest month, rainfall seasonality, and rainfall of the wettest month as correlates of distributional patterns across subregions. Our study supported the notion that Anonychomyrma radiated from a southern temperate origin into the tropical zone, with a preference for areas of montane rainforest that were stably cool and wet over the late quaternary.

Por que algumas espécies são amplamente distribuídas enquanto outras possuem estreita amplitude de distribuição? Essa questão há muito tempo tem motivado ecólogos a tentar entender as distribuições das abundâncias das espécies e como essas distribuições estão ligadas às tolerâncias das espécies. Espera-se que, em comunidades de plantas, a composição e a abundância das espécies variem de acordo com as tolerâncias individuais para diferentes condições climáticas, resultando em um menor número de espécies fisiologicamente tolerantes a condições mais estressantes e amplamente distribuídas no gradiente climático. Essa ideia é predita pela hipótese da tolerância fisiológica. A Mata Atlântica possui grande variação latitudinal e altitudinal, capturando gradientes relacionados com precipitação e temperatura, sendo assim uma ótima área de estudo para avaliar limites climáticos de espécies arbóreas. Uma maneira para classificar as tolerâncias das espécies e também identificar sob quais condições as espécies alcançam maior abundância (afiliação) é mapear suas distribuições através de gradientes climáticos, utilizando inventários florísticos. Diante desse contexto, nesta dissertação objetivamos investigar as amplitudes da distribuição de espécies arbóreas na Mata Atlântica ao longo de gradientes de temperatura e precipitação, bem como suas afiliações climáticas. Utilizamos dados de comunidades florestais do banco de dados TreeCo para obter dados de ocorrência e abundância de espécies arbóreas através do gradiente da Mata Atlântica (622 comunidades). Para as 2001 espécies analisadas neste trabalho, calculamos as amplitudes de ocorrência e o índice de afiliação em relação à temperatura média e à sazonalidade da precipitação. Identificamos que, como esperado pela hipótese da tolerância fisiológica, espécies que conseguem tolerar temperaturas mais frias são distribuídas ao longo de um amplo gradiente de temperatura, enquanto algumas espécies se restringem a locais com temperaturas mais quentes. Em relação à sazonalidade de precipitação, identificamos espécies amplamente distribuídas, ou seja de locais com menor sazonalidade até locais com maior sazonalidade, e espécies restritas a locais com maior sazonalidade, não seguindo o padrão da hipótese da tolerância fisiológica. Considerando as espécies significativamente afiliadas à temperatura e à sazonalidade da precipitação, verificamos que suas distribuições ótimas no gradiente climático tem associação ao padrão espacial biogeográfico da Mata Atlântica, onde se destacam dois blocos florestais predominantes: um grupo temperado sul e um grupo tropical norte. Why some species are widely distributed while others are concentrated into narrow amplitudes? For a long time, this question has motivated ecologists to investigate the distributions of species abundances and how they are linked to species tolerances. In plant communities, it is expected a variation in species composition and abundances according to individual species tolerances to different climatic conditions, resulting in a smaller number of species physiologically tolerant to more stressful conditions and widely distributed in the climatic gradient. This idea is predicted by the physiological tolerance hypothesis. The Atlantic Forest has a marked latitudinal and altitudinal range, capturing climatic gradients related to precipitation and temperature, which thus represent a great study area to evaluate tree species climatic limits. One way to classify species tolerances and identify under what conditions the species reach greater abundance (affiliation) is mapping species distributions across climatic gradients by using many floristic inventories. Under this perspective, the aim of this dissertation was to investigate the distribution ranges of tree species in the Atlantic Domain along temperature and precipitation gradients, and their climatic affiliations. We used forest communities data from the TreeCo database to obtain occurrence and abundance of tree species through the Atlantic Forest gradient (622 communities). For the 2001 species analyzed in this work, we calculated the ranges of occurrence and the affiliation index for mean temperature and precipitation seasonality. As expected by the physiological tolerance hypothesis, we found that species that tolerate lower temperatures are distributed across a wider temperature gradient, while some species are restricted to milder temperatures. Regarding the precipitation seasonality, we identified widely distributed species, i.e. from lower to greater precipitation seasonality, and species restricted to sites with greater seasonality, not following the physiological tolerance hypothesis. Considering the species significantly affiliated to temperature and/or to precipitation seasonality, we verified that their optimal distributions along the climatic gradients were associated with the biogeographic pattern of the Atlantic Forest, in which two forest blocks stand out: a temperate south group and a tropical northern group.

Delimiting species is an important, but frequently difficult aspect of systematics that should be addressed using data from multiple sources. Here we combine morphometric analyses and environmental characteristics to delimit species in the South Andean and Patagonian taxonomically difficult species-group composed by Mulinum spinosum, M. echinus and M. leptacanthum (Apiaceae-Azorelloideae). Molecular phylogenies have shown that these three species form part of a polytomy together with other Mulinum species, and therefore these data are not useful for their delimitation. We include measurements of 25 morphometric variables from 163 herbarium specimens and perform univariate and multivariate principal component analysis (PCA) and discriminant analysis (DA) to establish the limits amongst the three mostly sympatric, morphologically similar, and phylogenetically unresolved species. We also use 19 bioclimatic and three geographic variables from localities of the specimens to infer environmental characteristics of the taxa and test their relation with morphological variation. Morphological evidence supports the inclusion of M. echinus within the morphologically and climatically variable M. spinosum, and rejects its recognition as a distinct taxon at any rank. On the contrary, M. leptacanthum is considered a morphologically distinct species, generally restricted to high altitude areas of the southern Andes with a cooler and wetter climate. Within the widespread M. spinosum, environmental gradients of precipitation and temperature relate to morphological gradients (e.g., in leaf and inflorescence sizes, in leaf acicularity, and in fruit-wing width). These last results showed that the large morphological variation in vegetative and reproductive characteristics of this species that grows in arid and semiarid habitats are related to regional climatic gradients that have probably been important in the evolution of this species' plasticity, diversification, and differentiation. Fil: Fernández, Martina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Ezcurra, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Calviño, Carolina Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Predicting species distributions with changing climate has often relied on climatic variables, but increasingly there is recognition that disturbance regimes should also be included in distribution models. We examined how changes in rainfall and disturbances along climatic gradients determined demographic patterns in a widespread and long-lived tree species, Callitris glaucophylla in SE Australia. We examined recruitment since 1950 in relation to annual (200-600 mm) and seasonal (summer, uniform, winter) rainfall gradients, edaphic factors (topography), and disturbance regimes (vertebrate grazing [tenure and species], fire). A switch from recruitment success to failure occurred at 405 mm mean annual rainfall, coincident with a change in grazing regime. Recruitment was lowest on farms with rabbits below 405 mm rainfall (mean = 0-0.89 cohorts) and highest on less-disturbed tenures with no rabbits above 405 mm rainfall (mean = 3.25 cohorts). Moderate levels of recruitment occurred where farms had no rabbits or less disturbed tenures had rabbits above and below 405 mm rainfall (mean = 1.71-1.77 cohorts). These results show that low annual rainfall and high levels of introduced grazing has led to aging, contracting populations, while higher annual rainfall with low levels of grazing has led to younger, expanding populations. This study demonstrates how demographic patterns vary with rainfall and spatial variations in disturbances, which are linked in complex ways to climatic gradients. Predicting changes in tree distribution with climate change requires knowledge of how rainfall and key disturbances (tenure, vertebrate grazing) will shift along climatic gradients.

National audience

Deadwood dynamics play a key role in many forest ecosystems. Understanding the mechanisms involved in the accumulation and depletion of deadwood can enhance our understanding of fundamental processes such as carbon sequestration and disturbance regimes, allowing better predictions of future changes related to alternative management and climate scenarios. A conceptual framework for deadwood dynamics has been generally accepted but has not been broadly tested with empirical data. We used a large (n ¼ 6191) data set containing measurements of live and standing dead trees, and downed woody material, representing numerous woodland and forest types from throughout the Interior Western USA, to assess relationships between environmental factors and basic elements of forest structure, with particular focus on the various components of deadwood (i.e., fine woody debris, litter, duff and large deadwood, both standing and downed). Environmental gradients emerged as the most influential factors determining structure and deadwood dynamics of these diverse vegetation types. We found that dead components are approximately proportional to the live component and that all of the various components of structure can be ordered as a function of climatic gradients representing temperature and moisture. The postulate that maximum accumulation of biomass is associated with intermediate values of temperature and moisture was only partially supported by our results, indicating that conceptualizations of deadwood dynamics must be considered in the context of the particular disturbance regimes (e.g., fire, insect outbreaks, wind) most commonly associated with particular woodland and forest types. These findings are relevant to a wide range of applications, from ecosystem modeling to development of resource management plans under alternative future climates.

International audience; Aim :Most studies on latitudinal gradients of biodiversity have focused on gradients of species richness. Here we aim to test whether, on top of these strong diversity gradients, processes of community assembly vary along a latitudinal gradient of more than 33°. Location :China, latitude 18.67–51.86°N. Methods : We used species abundance distribution (SAD) data collected in 32 forest tree plots, and fitted a non-neutral model of community assembly to these SADs. We then calculated the fitted deviation from neutrality, delta, and looked for correlations between delta and geographical and environmental data. Results : The fitted parameter delta was positive in most plots, and was furthermore positively correlated with latitude and negatively with temperature, indicating a less even abundance distribution and a likely increase in the strength of environmental filtering in regions further from the tropics and with decreasing temperatures. These results imply that on top of reducing the species richness, cold temperature may impact community assembly processes by strengthening local environmental filtering. Main conclusions : Our results suggest a latitudinal gradient in tree community assembly process in Chinese forests, in which deviations from neutrality increase with latitude, probably because of an increase in environmental harshness.

As a part of the GLORIA-EUROPE project, the floristic diversity, frequency and species coverage in relation to the main ecological gradients (altitude,aspect) were studied in the alpine pasture (Primulo-Caricetum curvulae, Oreochloo-Juncetum trifidi) and subalpine dwarf shrub communities (Rhododendro myrtifolii - Vaccinetum ) of the four summits from the Pietrosul Rodnei massif (Romanian Carpathians). Floristic diversity is higher in the plant communities from lower altitude summits (Golgota, Gropile), while it decreases in communities, to higher summits (Buhaiescu, Rebra). For each 100 m increase in the altitude of subalpine-alpine summits, a decrease of approximately 10% was found in the number of vascular plant species. Arctic-Alpine species (Carex curvula, ¡uncus trifidus, Hieracium alpinum, Oreochloa disticha, etc.) and a Carpatho-Balkanic regional species (Rhododendron myrtifolium) have the highest frequency and coverage in these plant communities. In northern and eastern slope areas, where the vegetation cover is 15-30% lower than on western and southern slopes and the soil temperature is generally 1-3°C lower during the vegetative season (June-August), the mean number of species per square meter is 25% higher than in southern and western slope areas., [fr] Dans le cadre du projet GLORIA EUROPE on a étudié la diversité floristique, la fréquence et le recouvrement des espèces, par rapport aux principaux gradients écologiques (altitude, exposition), au sein des associations de prés alpins (Primulo-Caricetum curvulae, Oreochloo-Juncetum trifidi) et des buissons subalpins de petite taille (Rhododendro myrtifolii - Vaccinietum), sur quatre sommets dans le massif Pietrosul Mare (Les Carpates Roumaines). La diversité floristique est plus grande chez les associations de plantes des sommets avec des altitudes plus basses (Golgota, Gropile) et elle s'abaisse chez les associations des sommets plus hauts (Buhaiescu, Rebra). Dans le cas où l'altitude des sommets subalpins-alpins est 100 m plus élevée, on a constaté une réduction du nombre desespèces de plantes vascidaires avec 10%. La fréquence et le recouvrement les plus élevées dans ces associations appartiennent aux espèces arctico-alpines (Carex curvida, Juncus trifidus, Hieracium alpinum, Oreochloa disticha etc.) et à une espèce régionale carpato-balkanique (Rhododendron myrtifolium). Dans les aires de versants nord et est, où le recouvrement de la végétation est 15-30% plus bas que sur les versants ensoleillés, et où la température dans le sol est, généralement, 1-3° C plus réduite dans la saison de végétation (juin-août), le nombre des espèces sur un mètre carré est, en moyenne, de 25% plus grand que dans les aires de versants sud et ouest. [es] En el marco del proyecto GLORIA EUROPE hemos estudiado la diversidad florística, la frecuencia y la cobertura de las especies en relación con los principales gradientes ecológicos (altitud, exposición), con las asociaciones de pastos alpinos (Primulo-Caricetum curvulae, Oreochloo-Juncetum trifidi ) y con los matorrales bajos subalpinos (Rhododendro myrtifolii – Vaccinietum), todo ello en cuatro cimas del macizo Pietrosul Mare (Cárpatos Rumanos). La diversidad florística es mayor en las asociaciones de las cimas más bajas (Golgota, Gropile) y menor en las asociaciones de las cimas elevadas (Buhaiescu, Rebra). Cuando el intervalo altitudinal de las cimas subalpinas-alpinas es de 100 m la disminución en el número de plantas vasculares es aproximadamente del 10%. La mayor frecuencia y el más importante recubrimiento corresponden a las especies ártico-alpinas (Carex curvula, Juncus trifidus, Hieracium alpinum, Oreochloa disticha etc.) así como a una especie regional carpato-balcánica (Rhododendron myrtifolium). En las subparcelas de laderas norte y este, donde el recubrimiento vegetal es 15-30% menor que en las laderas soleadas, y donde la temperatura del suelo es generalmente 1-3° C más fría en el período vegetativo (junio-agosto), el número de especies en un metro cuadrado es, por término medio, un 25% mayor que en las subparcelas de las laderas meridionales y occidentales.

Hydrometeorological monitoring, as discussed here, describes the activities required to characterize the properties and processes of the hydrosphere as it exists in the three-dimensional mesoscale environment of the high-mountain catchment basins of the Hindu Kush-Himalaya (HKH) Mountains. Credible monitoring involves: (a) functional institutions; (b) operational instruments; (c) trained, motivated individuals; (d) scientific procedures; and (e) dedicated funding. Establishing a regional hydro-meteorological research facility in the HKH Mountains will involve developing solutions in the areas of integrated data collection and analysis procedures, instrument selection and placement, compatibility of monitoring instruments and procedures, training of personnel, procedures related to scale and modeling, ensuring accessibility of monitoring sites, and management, analysis, and archiving of the acquired data, all in the context of processes within the mountain basins, not in the adjacent lowlands. Mountain hydrometeorology is defined by a set of complex, three-dimensional, biophysical environments, produced by interactions among terrain, geology, and meteorology. The homogeneity seen from the distant lowlands becomes a complex mosaic of environments within the headwater basins. Altitude determines the properties of an atmospheric column extending upwards from a point within the mountains. These atmospheric properties determine the potential water and energy budgets at a point, or within a basin, in the mountains. Relief, slope aspect and angle, defines local topography.

International audience; Questions: How important is management disturbance on gamma species richness of woody plants at intermediate landscape scales? How is species richness related to other climatic and biotic factors in the study area? How does the assumption of spatial stationarity affect assessment of relationships among species richness and explanatory variables (e.g. management, biotic and climatic factors) across extensive study areas? Location: Central Spain (regions of Castilla y Le ' on, Madrid and Castilla-La Mancha). Scale: Extent: 150 000km2. Grain: 25km2 (5x5-km cells). Methods: Information from 21 064 plots from the 3SNFI was used to evaluate richness of tree and shrub species at intermediate landscape scales. In addition to variables well known to explain biodiversity, e.g. environmental and biotic factors, effect of management treatments was evaluated by assessing clearcutting, selection cutting, stand improvement treatments and agrosilvopastoral systems (dehesas). Results from GWR techniques were compared with those from OLS regression. Results: Patterns of gamma species richness, although strongly affected by both environmental and biotic variables, were also significantly modified by management factors. Species richness increased with percentage of selection cutting stands and improvement treatments but decreased with percentage of clearcutting stands. Reduced species richness of woody plants was associated with agrosilvopastoral practices. Species richness for trees was closely related to basal area, annual precipitation and topographic complexity; species richness for shrubs was closely related to topographic complexity and agrosilvopastoral systems. Most relationships between species richness and environmental or biotic factors were non-stationary. Relationships between species richness and management effects tended to be stationary, with a few exceptions. Conclusions: Landscape models of biodiversity in Central Spain were more informative when they accounted for effects of management practices, at least at intermediate scales. In the context of current rural abandonment, silvicultural disturbances of intermediate intensity increased gamma species richness of woody plants. Exclusion of factors such as agrosilvopastoral systems from models could have led to spurious relationships with other spatially co-varying factors (e.g. summer precipitation). Patterns of spatial variation in relationships, provided by GWR models, allowed formulating hypotheses about potential ecological processes underlying them, beyond generalizations resulting from global (OLS) models.

The taxonomy and ecology of the sorediate species of Menegazzia from the southernmost regions of Chile and Argentina and the South Atlantic Islands was recently published, only with sporadic reports from the more northern regions. In the present work the distribution patterns and habitat ecology of the sorediate species are discussed, with emphasis on the area north of 48º S. Eleven species are treated. Menegazzia subpertusa, an epiphyte of sclerophyll scrubs, is recorded from South America for the first time (Chile and Argentina). Menegazzia neozelandica has a disjunct distribution in Chile, with occurrences in Fray Jorge (Fourth Region of Chile) and on Islas Juan Fernández, and along the coast south of latitude 38º S. Menegazzia kawesqarica and M. tenuis are most common in the southernmost part of Chile, but are also found at high altitudes at lower latitudes. Additional treated species are M. chrysogaster, M. fumarprotocetrarica, M. globulifera, M. magellanica, M. norsorediata, M. sanguinascens and M. wandae. Several of the sorediate species are early colonisers of newly developed substrates. They show variable occurrences along light and humidity gradients. Distribution maps and a revised key are presented. Recientemente se han publicado datos sobre la taxonomía y ecología de las especies sorediosas de Menegazzia representadas en las regiones más australes de Chile y Argentina e islas del Atlántico Sur, además de registros esporádicos en zonas ubicadas más al norte en Chile. En este trabajo se discuten los patrones de distribución y la ecología del hábitat de 11 especies sorediosas, con especial enfásis en aquellas que se desarrollan al norte de los 48º S. Menegazzia subpertusa, un epífito de arbustos esclerófilos, se registra por primera vez en América (Chile y Argentina). Menegazzia neozelandica tiene una distribución discontinua en Chile; ha sido recolectada en Fray Jorge (Cuarta Región de Chile), Islas Juan Fernández y en regiones costeras al sur de los 38º S. Menegazzia kawesqarica y M. tenuis son más frecuentes en las zonas más australes de Chile; también se han encontrado en hábitats de altura y bajas latitudes. Se incluyen, además, M. chrysogaster, M. fumarprotocetrarica, M. globulifera, M. magellanica, M. norsorediata, M. sanguinascens y M. wandae. Varias especies sorediosas crecen como pioneras en sustratos jóvenes. Los patrones de distribución a lo largo de gradientes de humedad y de luz son variables. Se presentan mapas de distribución y clave de las especies.

Recientemente se han publicado datos sobre la taxonomia y ecologia de las especies sorediosas de Menegazzia representadas en las regiones mas australes de Chile y Argentina e islas del Atlantico Sur, ademas de registros esporadicos en zonas ubicadas mas al norte en Chile. En este trabajo se discuten los patrones de distribucion y la ecologia del habitat de 11 especies sorediosas, con especial enfasis en aquellas que se desarrollan al norte de los 48o S. Menegazzia subpertusa, un epifito de arbustos esclerofilos, se registra por primera vez en America (Chile y Argentina). Menegazzia neozelandica tiene una distribucion discontinua en Chile; ha sido recolectada en Fray Jorge (Cuarta Region de Chile), Islas Juan Fernandez y en regiones costeras al sur de los 38o S. Menegazzia kawesqarica y M. tenuis son mas frecuentes en las zonas mas australes de Chile; tambien se han encontrado en habitats de altura y bajas latitudes. Se incluyen, ademas, M. chrysogaster, M. fumarprotocetrarica, M. globulifera, M. magellanica, M. norsorediata, M. sanguinascens y M. wandae. Varias especies sorediosas crecen como pioneras en sustratos jovenes. Los patrones de distribucion a lo largo de gradientes de humedad y de luz son variables. Se presentan mapas de distribucion y clave de las especies.

This paper brings up again a paradox : on the one hand, the existence of levels that are homogeneous altitudinal belts defined by sets of botanical communities ; on the other hand, the climatic and induced bio-physical gradients, from which the levels are considered as a reflection. The study of mesoscale botanical transects in Mediterranean mountains and in the Alps leads to a distinction. The landscape geography shows today the fading of the classical zonations of human activities that were described at the beginning of the twentieth century, following the decline of these activities. The geography of flora, as for it, presents discontinuities corresponding to variations in the rate of substitution of species along the bio-physical gradients, L'article revient sur un paradoxe : d'une part, l'existence d'étages, bandes altitudinales homogènes définies par des complexes de communautés végétales ; d'autre part, les gradients climatiques et bio-physiques induits dont ces étages sont présentés comme le reflet. L'étude de transects botaniques d'échelle régionale suivis dans les montagnes méditerranéennes et dans le Massif alpin invite à établir une distinction. La géographie des paysages voit aujourd'hui les classiques étagements des activités humaines décrits au début du XXe siècle s'estomper à mesure de la déprise de ces activités. La géographie de la flore, elle, présente des discontinuités correspondant à des variations dans la vitesse de défilement des espèces sur le fil des gradients bio-physiques., Alexandre Frédéric. L'étagement de la végétation en montagne: un modèle à revisiter. In: L'information géographique, volume 67, n°1, 2003. pp. 45-59.

Adaptive radiation and reproductive isolation can determine the biogeographic structure of any species. We examine patterns of biotic variation in Embothrium coccineum, a Proteaceae tree that spans 20º of latitude and is both morphologically and genetically highly variable. We aim to: (1) explore the correspondence between these biotic patterns and current geographic and climatic gradients, and (2) determine whether and how those patterns are likely to respond to changing climate. We conducted separate Principal Components Analysis on biotic and abiotic sets of variables for 34 populations of Embothrium coccineum, accounting for a large fraction of the total variation in each. We then used canonical correlation analyses to optimize the match of those gradients onto each other. Smaller, rounder leaves and particular alleles typify the colder-drier parts of the range, while larger, lanceolate leaves and other alleles typify warmer-moister areas. Finally we mapped biotic profiles onto a predicted climatic landscape, based on doubling of CO2 projections. The climatic regime is predicted to shift geographically, but this lineage has successfully responded to repeated and dramatic climatic shifts since the Oligocene, and it should also be able to move and adapt quickly enough to meet the present challenge. More generally, our analytic approach can be extended to analysis of biotic and abiotic patterns in other species facing climatic challenges. Where there is enough biogeographic variation to provide adaptively relevant substrate, and where propagule dispersal is sufficiently extensive to keep up with the pace of spatial climatic shift, such taxa should be able to cope with shifting climate. Fil: Souto, Cintia Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación En Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; Argentina Fil: Smouse, Peter E.. Rutgers University. Department of Ecology, Evolution and Natural Resources; Estados Unidos