Publicação
Padrões de diversidade do género Euphorbia L. (Euphorbiaceae) em Angola: biogeografia e conservação
| Resumo: | Tropical regions harbor the majority of the Earth's species and a high number of endemic species. However, current impacts on biodiversity in the tropics are not easily reversible and change ecosystem functioning dramatically, with important social and economic consequences. Among tropical regions, particular attention should be given to the Sub-Saharan Africa (SSA) where plant diversity and their habitats are generally poorly documented and information for endemic species is still scarce. For most plants, data on distribution are only accessible in herbarium collections, which provide the only available information to describe geographic patterns of biodiversity. Within the SSA, Angola is one of the richest regions in terms of flora, that host a high level of endemism, but threats to this rich flora and their habitats are emerging, being imperative to conserve its biodiversity. Conserving biodiversity rich areas in Angola is challenging, because the country lacks in-depth taxonomic and ecological knowledge, especially for plants, and consequently species extinction risk assessments are very scarce. Euphorbia L. (Euphorbiaceae) is the second largest genus in the angiosperms in SSA (ca. 2000 taxa) and the major endemic plant radiation in Angola, including 86 native species with a large diversity of life forms (e.g. herbs, shrubs and trees, and among these several succulent species) 60% of which are endemics. However, despite this tremendous richness, there is still a lack of ecological, biogeographic and taxonomic knowledge about Euphorbia in the country. In this study, we assessed the diversity patterns of the Euphorbia species in Angola and used these new findings to devise future conservation programs for plant diversity. Specifically, species distributions were assessed from herbarium and plant databases, and related to the climatic classification of Köppen- Geiger and the WWF Ecoregions maps, using cluster and ordination analyses. The results revealed that most of the Euphorbia species occur in the Miombo (woodland and savanna of Angola) and in coastal and escarpment regions and that some species are restricted to the arid zones of southern Angola. For each of these regions, centers of diversity and/or endemism were identified, which will be crucial for the persistence of endemic species of Euphorbia. This information provided a basis for a future re-evaluation of the protected areas network of Angola, aiming to promote the conservation of the unique plant diversity of the country. |
|---|---|
| Autores principais: | Frazão, Raquel Vanessa dos Santos |
| Assunto: | Biodiversidade Endemismo Padrões de Diversidade Áreas Protegidas Conservação Teses de mestrado - 2018 |
| Ano: | 2018 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | português |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Tropical regions harbor the majority of the Earth's species and a high number of endemic species. However, current impacts on biodiversity in the tropics are not easily reversible and change ecosystem functioning dramatically, with important social and economic consequences. Among tropical regions, particular attention should be given to the Sub-Saharan Africa (SSA) where plant diversity and their habitats are generally poorly documented and information for endemic species is still scarce. For most plants, data on distribution are only accessible in herbarium collections, which provide the only available information to describe geographic patterns of biodiversity. Within the SSA, Angola is one of the richest regions in terms of flora, that host a high level of endemism, but threats to this rich flora and their habitats are emerging, being imperative to conserve its biodiversity. Conserving biodiversity rich areas in Angola is challenging, because the country lacks in-depth taxonomic and ecological knowledge, especially for plants, and consequently species extinction risk assessments are very scarce. Euphorbia L. (Euphorbiaceae) is the second largest genus in the angiosperms in SSA (ca. 2000 taxa) and the major endemic plant radiation in Angola, including 86 native species with a large diversity of life forms (e.g. herbs, shrubs and trees, and among these several succulent species) 60% of which are endemics. However, despite this tremendous richness, there is still a lack of ecological, biogeographic and taxonomic knowledge about Euphorbia in the country. In this study, we assessed the diversity patterns of the Euphorbia species in Angola and used these new findings to devise future conservation programs for plant diversity. Specifically, species distributions were assessed from herbarium and plant databases, and related to the climatic classification of Köppen- Geiger and the WWF Ecoregions maps, using cluster and ordination analyses. The results revealed that most of the Euphorbia species occur in the Miombo (woodland and savanna of Angola) and in coastal and escarpment regions and that some species are restricted to the arid zones of southern Angola. For each of these regions, centers of diversity and/or endemism were identified, which will be crucial for the persistence of endemic species of Euphorbia. This information provided a basis for a future re-evaluation of the protected areas network of Angola, aiming to promote the conservation of the unique plant diversity of the country. |
|---|