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1.
Open heathlands of the Strait of Gibraltar region constitute a singularvegetation type within the Mediterranean Basin owing to their high biodiversitylevels and distinct features in the biological aspects of endemism. However,they have been traditionally depicted as low profitable, tree-less, barrenlandsand have been either overlooked in conservation policies or included inextensive pine-tree afforestation programmes. Nowadays, most of the existingpine plantations are no longer exploited and have become dense pine woodlands.Here we present the results of a comparative analysis aimed to ascertain theeffects of pine stands on the structure and diversity of the woody component ofthese mediterranean heathlands. Ten sampling sites were located within thestudyarea, each consisting of two adjacent subsamples: an open heathland and aneighbouring heathland under pine-tree cover. Woody species richness andoverallshrub cover was much lower in pine-tree heath understoreys. This drop in coverwas more marked for short-lived species (seeders and withering resprouters),implying a decrease of the life-history diversity and also having noticeableconsequences in homogenizing the floristic composition of heath patches underpine trees. Heathland narrow endemics dropped significantly in pine stands,showing greater sensitivity to afforestation than nonendemics. We suggest thatthe open heathlands of the Strait of Gibraltar should be given furtherattentionin EU and IUCN conservation policies. Programmes should be implemented toprogressively eliminate abandoned pine plantations so as to restore andpreservethese highly diverse mediterranean heathlands.  相似文献   

2.
Geospatial patterns in the distribution of regional biodiversity reflect the composite processes that underpin evolution: speciation, dispersal and extinction. The spatial distribution and phylogeny of a globally widespread and species rich bird family (Rallidae) were used to help assess the role of large‐scale biogeographical processes in diversity and diversification. Here, we examine how different geostatistical diversity metrics enhance our understanding of species distribution by linking occurrence records of rail species to corresponding species level phylogeny. Tropical regions and temperate zones contained a large proportion of rail species richness and phylogenetic diversity whilst small islands in Australian, Oceanian and Oriental regions held the highest weighted and phylogenetic endemism. Our results suggest that habitat connectivity and dispersal were important ecological features in rail evolution and distribution. Spatial isolation was a significant driver of diversification where islands in Oceania were centres of neo‐endemism with recent multiple and independent speciation events and could be considered as nurseries of biodiversity. Palaeo‐endemism was mostly associated with older stable regions, so despite extensive long distance range shifting these areas retain their own ancient and distinct character. Madagascar was the major area of palaeo‐endemism associated with the oldest rail lineages and could be considered a museum of rail diversity. This implies a mixture of processes determine the current distribution and diversity of rail clades with some areas dominated by recent ‘in situ’ speciation while others harbour old diversity with ecological traits that have stood the test of time.  相似文献   

3.
Over the last few decades, marked land use changes have taken place in many Mediterranean ecosystems. For example, many chestnut groves in France are now abandoned and have turned into 'natural' coppice stands while others are now clear-cut every 10 or 15 years for wood. Species composition and life form diversity of the plant communities have changed markedly both in the abandoned groves and in the periodically clear-cut coppice stands. What are the consequences of these changes on biodiversity at local and regional scales, and what are the implications for 'new forestry' management intended to conserve biodiversity at the same time as it optimizes productivity and profitability? To answer these questions we studied plant species diversity in the understorey strata along a successional gradient including cultivated grove; abandoned grove; young (15 years old), medium (40 years), and old (>55 years) coppice stands. The results showed that species richness decreased quickly but not steadily along this gradient, but life-form spectra data highlighted that the high levels of plant species biodiversity in cultivated groves were due primarily to the large number of therophytes (annual plants). At a shorter time scale, we also studied the consequences of experimental clear-cutting on plant species biodiversity. Direct measurements over four years showed that species richness and diversity in the understorey increased in the first two years after clear-cutting, but decreased during the 3rd and 4th years. This decrease corresponded closely with a steady increase in Leaf Area Index of the forest canopy. These results have been used to suggest some possible ways to manage the biodiversity in these ecosystems.  相似文献   

4.
The aim of this study was to estimate the polleniferous potential of the most common plant communities and crops across the landscape through the study of pollen loads collected by Apis mellifera. We analysed pollen load samples from hives located in Mallorca (western Mediterranean) for one year and compared the results with a phytosociological study of the foraging area. We also analysed meteorological data to evaluate the influence of some environmental factors on the pollen production phenology. We identified 74 different pollen types (66.2% from native flora, 25.7% from exotic flora, and 8.1% from crops) belonging to 33 families. The highest polleniferous potentials in the landscape were attained by sclerophyllous forests (Quercetea ilicis) in spring, crops in autumn, wild annual rangelands (Stellarietea mediae) in winter and gardens in late summer. Our results suggest that the higher the coverage present in a vegetation class, the higher the quantity and diversity of pollen that may be provided to pollinators; therefore, its polleniferous potential may be higher. Some meteorological conditions (rainfall, temperature and daily hours of sunlight) may affect this potential through their influence on flowering phenology.  相似文献   

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Poschenrieder  Charlotte  Bech  Jaume  Llugany  Mercè  Pace  Alina  Fenés  Eva  Barceló  Juan 《Plant and Soil》2001,230(2):247-256
The accumulation of Cu in roots and shoots of 32 plant species growing on soils with a wide range of Cu concentrations (30–18 500 g g–1 total soil Cu) located in Collserola Mountain (Barcelona, Spain) was analysed. High Cu availability decreased the species diversity in the Hyparrhenietum hirto-pubescentis, the natural plant association at the study sites. Shoot and root Cu concentrations in relation to extractable soil Cu concentrations were used for the evaluation of the Cu resistance strategy in the different species. Saturation of Cu accumulation in roots was observed in most species. Hyparrhenia hirta was the most efficient shoot excluder, while the linear increase of shoot Cu with the Cu soil concentration exhibited the highest slope in Hirschfeldia incana. Most species accumulated more Cu in roots than in shoots. High shoot/root Cu ratios were only found in the highly Cu-resistant Hirschfeldia incana, in the resistant or moderately resistant Spartium junceum and Reseda sp. (R. lutea and R. phyteuma), and in the much less resistant Ononis natrix. Only two species, Hirschfeldia incana and Sedum sediforme were able to support the extreme Cu-toxicity conditions on soils with 5000–16 800 g g–1 extractable Cu. Among the grass species tested Hyparrhenia hirta was the most Cu-resistant species (up to 1950 g g–1 extractable soil Cu). The potential usefulness of these pseudometallophytes for phytoremediation of Cu-contaminated soils is discussed.  相似文献   

8.

Aim

To investigate phylogeographic patterns among and within co‐occurring sea snake species from Australia's endemic viviparous Aipysurus lineage, which includes critically endangered species, and evaluate the conservation implications of geographically structured patterns of genetic divergence and diversity.

Location

Australia's tropical shallow water marine environments spanning four regions: Great Barrier Reef (GBR), Gulf of Carpentaria (GoC), Timor Sea (TS) and coastal WA (WAC).

Methods

Samples from >550 snakes representing all nine nominal Aipysurus group species were obtained from throughout their known Australian ranges. Coalescent phylogenetic analyses and Bayesian molecular dating of mitochondrial DNA, combined with Bayesian and traditional population genetic analyses of 11 microsatellite loci, were used to evaluate genetic divergence and diversity.

Results

Mitochondrial DNA revealed highly congruent phylogeographic breaks among co‐occurring species, largely supported by nuclear microsatellites. For each species, each region was characterized by a unique suite of haplotypes (phylogroups). Divergences between the TS, GoC and/or GBR were invariably shallow and dated as occurring 50,000–130,000 years ago, coinciding with the cyclic Pleistocene emergence of the Torres Strait land bridge. By contrast, sea snakes from coastal WA were consistently highly divergent from other regions and dated as diverging 178,000–526,000 years ago, which was not associated with any known vicariant events.

Main Conclusions

Previously unappreciated highly divergent sea snake lineages in coastal WA potentially represent cryptic species, highlighting this region as a high‐priority area for conservation. The cyclic emergence of the Torres Strait land bridge is consisted with observed divergences between the TS, GoC and/or GBR; however, processes involved in the earlier divergences involving the WAC remain to be determined. The observed strong population genetic structures (as surrogates for dispersal) indicate that sea snakes have limited potential to reverse population declines via replenishment from other sources over time frames relevant to conservation.
  相似文献   

9.
Aim The aims of this study were to assess the distribution of putative Mediterranean refugia of plants, to compare the locations of refugia and those of regional hotspots of plant biodiversity, and to provide a critical analysis of the Mediterranean refugium paradigm. Furthermore, we consider how biogeographical and genetic results can be combined to guide global conservation strategies. Location The Mediterranean region. Methods We started from a detailed analysis of the scientific literature (1993–2007) in order to identify refugia in the Mediterranean region, based on intra‐specific phylogeographical studies of plant species. We used population locations together with gene‐pool identity to establish the database, comparing patterns of phylogeographical concordance with the locations of Mediterranean refugia. We then tested the biogeographical congruence between two biodiversity components, namely phylogeographical refugia and regional hotspots. Results We identified 52 refugia in the Mediterranean bioclimatic region and confirmed the role played by the three major peninsulas, with a shared total of 25 refugia. We emphasize the importance of areas that have previously been attributed a lesser role (large Mediterranean islands, North Africa, Turkey, Catalonia). Of the 52 refugia identified, 33 are situated in the western Mediterranean Basin and 19 in the eastern part. The locations of the phylogeographically defined refugia are significantly associated with the 10 regional hotspots of plant biodiversity, with 26 of these refugia (i.e. 50%) occurring within the hotspots. Main conclusions The locations of refugia are determined by complex historical and environmental factors, the cumulative effects of which need to be considered because they have occurred since the Tertiary, rather than solely during the last glacial period. Refugia represent climatically stable areas and constitute a high conservation priority as key areas for the long‐term persistence of species and genetic diversity, especially given the threat posed by the extensive environmental change processes operating in the Mediterranean region. The refugia defined here represent ‘phylogeographical hotspots’; that is, significant reservoirs of unique genetic diversity favourable to the evolutionary processes of Mediterranean plant species.  相似文献   

10.
The Western Ghats (WG) mountain chain in peninsular India is a global biodiversity hotspot, one in which patterns of phylogenetic diversity and endemism remain to be documented across taxa. We used a well‐characterized community of ancient soil predatory arthropods from the WG to understand diversity gradients, identify hotspots of endemism and conservation importance, and highlight poorly studied areas with unique biodiversity. We compiled an occurrence dataset for 19 species of scolopendrid centipedes, which was used to predict areas of habitat suitability using bioclimatic and geomorphological variables in Maxent. We used predicted distributions and a time‐calibrated species phylogeny to calculate taxonomic and phylogenetic indices of diversity, endemism, and turnover. We observed a decreasing latitudinal gradient in taxonomic and phylogenetic diversity in the WG, which supports expectations from the latitudinal diversity gradient. The southern WG had the highest phylogenetic diversity and endemism, and was represented by lineages with long branch lengths as observed from relative phylogenetic diversity/endemism. These results indicate the persistence of lineages over evolutionary time in the southern WG and are consistent with predictions from the southern WG refuge hypothesis. The northern WG, despite having low phylogenetic diversity, had high values of phylogenetic endemism represented by distinct lineages as inferred from relative phylogenetic endemism. The distinct endemic lineages in this subregion might be adapted to life in lateritic plateaus characterized by poor soil conditions and high seasonality. Sites across an important biogeographic break, the Palghat Gap, broadly grouped separately in comparisons of species turnover along the WG. The southern WG and Nilgiris, adjoining the Palghat Gap, harbor unique centipede communities, where the causal role of climate or dispersal barriers in shaping diversity remains to be investigated. Our results highlight the need to use phylogeny and distribution data while assessing diversity and endemism patterns in the WG.  相似文献   

11.
Several components of diversity (ecological, taxonomic, chorological and morphological– functional) were studied in the woody vegetation of the cork oak forests in the northern Straits of Gibraltar Region, and their relationship to the two main environmental gradients (one mainly climatic—precipitation, fog—and another secondary related to the disturbance and hydric stress associated with hillslope orientation). An inventory of the woody species and their cover measure was carried out on 94 plots. The relationship between the components of diversity and the main environmental gradients was analysed by means of regression analysis. Decreases of species richness, Shannon diversity index, Western Mediterranean species cover, percentage of endemism and the share of the Herrera Syndrome I in diversity were related to the increase of the precipitation and the fog. However, the cover and percentage of species of the Circum-Mediterranean and Mediterranean-Eurosiberian chorological groups increase with the precipitation and the fog. Disturbance and hydric stress associated with hillslope orientation, have a negative effect on specific richness of the Mediterranean-Eurosiberian chorological group and taxonomic singularity, but its have a positive effect on the share of the Herrera Syndrome I in diversity. The number of edaphic endemisms is associated mainly with disturbance. In the cork forests does not exist an inverse relationship between the number of endemisms and floristic richness, as it happens in other Mediterranean areas. It has suggested that this pattern is due to effect of competitive exclusion associated with disturbance in vegetation on relatively fertile substrate.  相似文献   

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Gathered food plants (GFPs) (wild and weeds) are crucial for understanding traditional Mediterranean diets. Combining open interviews and free-listing questionnaires, we identified 215 GFP items, i.e., 53 fungi and 162 from 154 vascular plant species. The variation in frequency and in salience among the items follows a rectangular hyperbola. Highly salient species were Silene vulgaris (Moench) Garcke, Scolymus hispanicus L., and Pleurotus eryngii (DC.: Fr.) Quélet. Salience and frequency showed no correlation with the expected health benefits of each species. Regional frequency in the Mediterranean and local frequency are directly related. Thus, local food plants are much less “local” than expected. Different types of culinary preparations provide the most information in the cluster analysis of variables. The cluster analysis of items produced a tree with 10 clusters that form culture-specific logical entities, allowing people to structure their environment. Within each cluster, plant species are replaced and incorporated provided they resemble the general profile. This allows innovation and adaptation on a local level and explains the differences between adjacent localities in the list of species. Two types of clusters or species complexes are described: “species-labeled” and “uses-labeled.” Lastly, we discuss the underlying empirical basis of the ethnoclassification in the Mediterranean area.  相似文献   

14.
Plant community dynamics in Mediterranean basin ecosystems are mainly driven by an alternation of episodes of human intervention and land abandonment. As a result, a mosaic of plant communities has evolved following different stages of degradation and regeneration. Some authors has relate secondary succession to abandoned culture lands and regeneration to natural systems with abandonment of livestock or forestry exploitation. In this paper, the dynamics of shrublands in mid-mountain areas in the South of Spain after disturbance and land abandonment has been studied. The plant cover and 13 environmental variables of 137 selected sites on the Grazalema mountains was analysed to determine the vegetation pattern in relation to environmental factors and the succession types, either regenerative or secondary succession. The results show that today the Grazalema mountains have a heterogeneous vegetation pattern. Besides physical factors such as altitude or soil , human disturbance has modulated current vegetation patterns and dynamics. Two main types of vegetation dynamics can be distinguished in the study area. In areas affected by cutting, regeneration results in rich and dense shrub land, with resprouters as dominant species. In areas affected by recurrent wildfires or agriculture, secondary succession became dominant, resulting in less diverse shrubland, due to the dominance of seeders and decrease in resprouter species richness and cover.  相似文献   

15.
The purpose of his research was to describethe organization of genetic variation in thefederally endangered plant taxon Eriogonumovalifolium var. vineum using allozymes. Such information can help prioritize sites andmanagement choices for capturing andmaintaining genetic variation and can reducethe number of populations necessary to committo conservation, thus reducing costs andconflicts with competing land uses. Information on genetic diversity patterns alsoprovides insight into evolutionary anddemographic history of a taxon which canprovide means to assess future risk of erosionof diversity. Similar to other Eriogonumovalifolium varieties, E. ovalifoliumvar. vineum is diverse atboth the taxon (proportion of polymorphic loci[P] = 0.55 and alleles per locus [A] =5.45 [SD = 2.5]) and population (P = 0.56 [SD =0.11] and A = 2.68 [SD = 0.35]) levels. Gene diversity (H e) withinpopulations averaged 0.19 (SD = 0.03). Wefound some evidence for limited clonalreproduction within populations. Populationswere moderately differentiated from one another(S = 0.14) and showed moderatedeviations from Hardy-Weinberg equilibriumwithin populations (f = 0.14 and F =0.19). Mean Nei's genetic distance (D)among all pairs of populations was 0.02. Populations with high levels of multiplemeasures of genetic diversity, high levels ofdifferentiation, and low levels of apparentinbreeding are suggested as conservationpriorities.  相似文献   

16.
Recent floristic efforts in the Pacific Northwest (PNW) have now made it possible to characterize the broad‐scale patterns of fern and lycophyte diversity across this large and geologically‐complex region of western North America. The physiography of the PNW has been developing for over 200 million years, but Pleistocene glaciation‐induced migrations and recolonizations have strongly influenced the assembly of the flora. With the high dispersal potential of fern and lycophyte spores, the distribution patterns of pteridophytes may be representative of habitat suitability more than dispersal constraints. Our objective was to describe the biodiversity of pteridophytes in the PNW, determine the spatial distribution of that biodiversity in terms of phylogenetic diversity, identify centers of regional endemism, explore the correlations between biodiversity and environmental variables, and infer possible influences of past glaciation on the pteridophyte flora. We obtained presence‐only distribution data from two online databases. A phylogenetic tree was constructed using chloroplast DNA sequence data from GenBank. We used the Biodiverse software package to estimate and map phylogenetic diversity and phylogenetic endemism across the PNW, and to identify those regions of the PNW where diversity was higher or lower than expected in comparison to randomization models. Environmental correlates of diversity were identified using principal components analysis with bioclimatic data from WorldClim.org, and we used Maxent to predict habitat suitability for species under past and future climate conditions. We found evidence for the influence of past glaciations and glacial refugia on the patterns of pteridophyte diversity, that moisture availability and cold temperatures are strongly correlated with patterns of genus richness, phylogenetic diversity, and phylogenetic endemism. We infer that the topographic complexity of the region may be driving the assembly of the pteridophyte flora indirectly by influencing climate and precipitation patterns.  相似文献   

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18.
The representatives of the enigmatic genus Leptopanorpa MacLachlan are characterized by exaggeratedly elongated male abdomens and are likely endemic to Java and Sumatra, Indonesia. Here, we present a taxonomical revision of 14 species of Leptopanorpa, including two new species: Leptopanorpa linyejiei sp. n. from West Java and Leptopanorpa majapahita sp. n. from East Java. A key to species of Leptopanorpa is provided. Leptopanorpa sieboldi MacLachlan is treated as a junior synonym of Leptopanorpa charpentieri (Burmeister), and Leptopanorpa pi decorata Lieftinck is synonymized with Leptopanorpa pi (van der Weele). Leptopanorpa peterseni Lieftinck is reported from Bali for the first time. In order to unravel the phylogeny of Leptopanorpa and other groups with elongated male abdomens, maximum parsimony and Bayesian inference analyses were performed based on 61 morphological characters and partial sequences of one nuclear gene (28S ribosomal RNA) and two mitochondrial genes (cytochrome c oxidase subunits I and II). Thirty-three species in Panorpoidea were selected as in-group taxa and two species in Choristidae as out-group taxa. The results highly support a monophyletic Leptopanorpa, which nests within a paraphyletic Neopanorpa van der Weele. Both parsimonious and Bayesian results suggest that Leptopanorpa can be divided into four subclades. We elucidated the evolutionary history of Leptopanorpa with regard to the paleogeological events of Sundaland and corroborated the multiple origins of elongated male abdomens in Panorpoidea. We also hypothesized that the ventral hook on the male abdominal sternum VI of L. linyejiei sp. n. is very likely used to control the female's abdomen during copulation.  相似文献   

19.
Abstract: The middle Cambrian strata of the Iberian Chains (north‐eastern Spain) and the Montagne Noire (southern France) record an adaptative radiation of cinctans and trilobites, which spanned the Leonian–early Languedocian interval. A diachronous diversity peak was reached by both benthic groups when favourable palaeoenvironmental conditions (clayey vs. silty substrates) were established. The acme in diversity was followed by a gradual decline and a barren interval associated with the onset of the mid‐Languedocian regression, well constrained throughout the western Mediterranean region. For trilobites, the aftermath of the regression is characterized by a late‐Languedocian major faunal turnover of families, followed by a renewed Furongian–early Tremadocian radiation related to the stepwise immigration of trilobite invaders from northern and eastern Gondwana, under persistent transgressive conditions. In contrast, the cinctans reappeared only patchily in late‐Languedocian monospecific coquinas and finally disappeared before the Furongian. Thus, the late Languedocian is a crucial interval in which to analyse the decline in diversity and final extinction of cinctans in the aftermath of the mid‐Languedocian regression.  相似文献   

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