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Endemic Plant Species (endemic + plant_species)
Selected AbstractsExtinction-Rate Estimates for a Modern Neotropical FloraCONSERVATION BIOLOGY, Issue 5 2002Nigel C. A. Pitman We present the first quantitative estimates of extinction rate in a complete Neotropical flora based on historical plant-collection records, quantitative measurements of forest loss and plant diversity, and the conservation status of endemic plant species in Ecuador. Our analyses suggest that 19,46 endemic plant species have gone extinct in Ecuador over the last 250 years, mostly because of habitat loss, and therefore are now globally extinct. An additional 282 species, nearly 7% of Ecuador's endemic flora, qualify as critically endangered. We found evidence of impending large-scale plant extinctions in the country's coastal and Andean forests, but little extinction and low potential for extinction in the Amazonian lowlands. Resumen: Las preocupaciones sobre las elevadas tasas de extinción en los trópicos son una característica común en la literatura sobre conservación, pero las mediciones directas son escasas. Presentamos las primeras estimaciones cuantitativas de la tasa de extinción en una flora neotropical completa basada en los expedientes históricos de colecciones de plantas, las mediciones cuantitativas de la pérdida de bosque y de diversidad y el estado de conservación de especies de plantas endémicas en Ecuador. Nuestro análisis sugiere que 19,46 especies de plantas se han extinguido en el Ecuador a lo largo de los últimos 250 años, debido principalmente a la pérdida de hábitat y por lo tanto son ahora extintas a nivel mundial. Además 282 especies, cerca del 7% de la flora endémica del Ecuador califica como críticamente amenazada. Encontramos indicaciones de inminentes extinciones de gran escala en el país, tanto en los bosques costeros como en los bosques de los Andes, pero poca extinción y bajo potencial de extinción en las tierras bajas del Amazonas. [source] The antiquity of Madagascar's grasslands and the rise of C4 grassy biomesJOURNAL OF BIOGEOGRAPHY, Issue 10 2008William J. Bond Abstract Aim, Grasslands and savannas, which make up > 75% of Madagascar's land area, have long been viewed as anthropogenically derived after people settled on the island c. 2 ka. We investigated this hypothesis and an alternative , that the grasslands are an insular example of the post-Miocene spread of C4 grassy biomes world-wide. Location, Madagascar, southern Africa, East Africa. Methods, We compared the number of C4 grass genera in Madagascar with that in southern and south-central African floras. If the grasslands are recent we would expect to find fewer species and genera in Madagascar relative to Africa and for these species and genera to have very wide distribution ranges in Madagascar. Secondly, we searched Madagascan floras for the presence of endemic plant species or genera restricted to grasslands. We also searched for evidence of a grassland specialist fauna with species endemic to Madagascar. Plant and animal species endemic to C4 grassy biomes would not be expected if these are of recent origin. Results, Madagascar has c. 88 C4 grass genera, including six endemic genera. Excluding African genera with only one or two species, Madagascar has 86.6% of southern Africa's and 89.4% of south-central Africa's grass genera. C4 grass species make up c. 4% of the flora of both Madagascar and southern Africa and species : genus ratios are similar (4.3 and 5.1, respectively). Turnover of grasses along geographical gradients follows similar patterns to those in South Africa, with Andropogoneae dominating in mesic biomes and Chlorideae in semi-arid grassy biomes. At least 16 monocot genera have grassland members, many of which are endemic to Madagascar. Woody species in frequently burnt savannas include both Madagascan endemics and African species. A different woody flora, mostly endemic, occurs in less frequently burnt grasslands in the central highlands, filling a similar successional niche to montane C4 grasslands in Africa. Diverse vertebrate and invertebrate lineages have grassland specialists, including many endemic to Madagascar (e.g. termites, ants, lizards, snakes, birds and mammals). Grassland use of the extinct fauna is poorly known but carbon isotope analysis indicates that a hippo, two giant tortoises and one extinct lemur ate C4 or CAM (crassulacean acid metabolism) plants. Main conclusions, The diversity of C4 grass lineages in Madagascar relative to that in Africa, and the presence of plant and animal species endemic to Madagascan grassy biomes, does not fit the view that these grasslands are anthropogenically derived. We suggest that grasslands invaded Madagascar after the late Miocene, part of the world-wide expansion of C4 grassy biomes. Madagascar provides an interesting test case for biogeographical analysis of how these novel biomes assembled, and the sources of the flora and fauna that now occupy them. A necessary part of such an analysis would be to establish the pre-settlement extent of the C4 grassy biomes. Carbon isotope analysis of soil organic matter would be a feasible method for doing this. [source] Inbreeding and inbreeding depression in a threatened endemic plant, the African violet (Saintpaulia ionantha ssp. grotei), of the East Usambara Mountains, TanzaniaAFRICAN JOURNAL OF ECOLOGY, Issue 3 2010Johanna Kolehmainen Abstract Mating among closely-related individuals in small and isolated plant populations may result in reduced vigour of the inbred offspring, i.e. inbreeding depression, especially in naturally outbreeding plants. Occurrence of inbreeding and inbreeding depression was studied in Saintpaulia ionantha ssp. grotei, a threatened endemic plant species with a narrow ecological amplitude from the East Usambara Mountains. The level of inbreeding (measured as the fixation index, F) was investigated in twelve populations by analyzing variation at one microsatellite marker locus. The effect of one generation of selfing and outcrossing on the progeny fitness was studied by controlled crosses in two small patches that differ in the level isolation. The fixation index (F) across the populations was on the average 0.21 and varied among the populations from substantial inbreeding (F = 0.58) to surplus heterozygosity (F = ,0.29). High inbreeding depression (,) was observed at early and late stages of the life-cycle. The isolated patch exhibited lower inbreeding depression than did the non-isolated patch. The results of this study suggest that inbreeding and subsequent inbreeding depression are potential threats to the survival of Saintpaulia populations. Résumé L'accouplement d'individus étroitement liés, dans des petites populations végétales isolées, peut aboutir à une vigueur moindre de la progéniture de même souche, c'est-à-dire une dépression due à l'endogamie, spécialement chez des plantes qui sont naturellement exogames. L'occurrence de l'endogamie et de la dépression qui y est liée a étéétudiée chez le Saintpaulia ionantha spp. grotei, une plante endémique menacée qui n'a qu'une faible amplitude écologique dans l'est des Usambara Mountains. On a recherché le taux d'endogamie (mesuré par l'indice de fixation F) dans 12 populations en analysant la variation d'un locus microsatellite marqueur. L'effet d'une génération d'auto- et d'allofécondation sur l'aptitude (fitness) de la progéniture a étéétudié par des croisements contrôlés dans deux petites parcelles dont le degré d'isolement différait. L'indice de fixation F dans les populations était en moyenne de 0,21 et il variait d'une autofécondation substantielle (F = 0,58) à une hétérozygosité en surplus (F = ,0,29). Une forte dépression due à l'endogamie (,) a été observée aux stades précoce et tardif du cycle vital. La parcelle isolée a présenté une dépression liée à l'endogamie moins forte que celle de la parcelle non isolée. Les résultats de cette étude suggèrent que l'auto-fécondation et la dépression qui en résulte sont des menaces potentielles pour la survie des populations de Saintpaulia. [source] Developing a blueprint for conservation of the endangered longleaf pine ecosystem based on centers of Coastal Plain plant endemismAPPLIED VEGETATION SCIENCE, Issue 1 2006Bruce A. Sorrie Abstract Question: Can the geographic patterning of endemic plant species inform reserve selection in a region of high endemism? Location: The Southeastern Coastal Plain of North America, focusing primarily on the imperiled longleaf pine (Pinus palustris P. Miller) ecosystem. Methods: We documented the high level of plant endemism in the region, and characterized the endemic taxa into distributional subregions. Results: A total of 1630 plant taxa are endemic to the Coastal Plain, a large proportion of which are endemic to phytogeographical subregions within the Coastal Plain, with particularly large numbers of narrow endemics occurring in the East Gulf Coastal Plain and Florida Peninsula. Conclusions: This pattern of local endemism presents challenges in conserving the full biota of the region: a reserve system focusing on few and large conservation areas has theoretical benefits for long-term management and viability, but will fail to capture many local endemics. We propose that the dispersed distribution of endemic species will require a mixture of large core reserves and smaller satellite reserves. [source] Alien and endemic flora at reference and non-reference sites in Mediterranean-type streams in PortugalAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2007Francisca C. Aguiar Abstract 1.A comparison was made between a variety of alien and endemic plant species from 272 aquatic and riparian habitats in Portuguese Mediterranean-type streams in reference condition , i.e. near-natural river corridors , and non-reference condition. The objective was to detect differences in relative proportion and cover between these species groups. The differences in endemic and alien flora from siliceous and calcareous river types were also analysed. Environmental and human disturbance factors were related with the richness and cover of both species groups. 2.A total of 568 species were found, of which 44 were alien and 28 were endemic. Alien species were present at 91% of the surveyed locations, and were consistently more widespread at non-reference sites than at reference ones for both river types, with calcareous sites having a higher invasibility. Endemic species occurred at 45% of the sampling sites and displayed a significantly lower richness and cover than their alien counterparts. 3.Alien richness and cover were positively related to direct human disturbance within the river systems, and with floodplain uses such as urban occupation, intensive agriculture, and nutrient inputs. Endemic species also respond to anthropogenic variables, rather than to climatic and geographical ones, with richness and cover increasing as human impacts on fluvial systems and related floodplains decrease. 4.Comprehensive control of alien invasive species and the protection of endemic plant populations will require attempts at monitoring ecological river integrity, and the achievement of ,good ecological status' , one of the goals of the European Union's Water Framework Directive. Portuguese riparian areas must be managed in such a way as to protect the relatively few preserved riparian habitats by lowering the direct and indirect pressures in fluvial corridors and thus preventing future alien plant invasions. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||