RESUMO
The Gran Chaco is a wide ecologic-geographic region comprising northern Argentina, western Paraguay, southern Bolivia and the southwestern extreme of Brazil. This region exhibits extreme temperatures, annually regular frosts, and sedimentary soils; it has been dramatically threatened by agriculture expansion in recent decades. Therefore, increasing knowledge of plant diversity is critical for conservation purposes. We present a Legume checklist of the Gran Chaco ecoregion including conservation status of its endemic species. Leguminosae is the third most diverse plant family in the Neotropics. Assuming a rigorous spatial definition of the Gran Chaco, we recorded 98 genera, 362 species, and 404 specific and infraspecific taxa. Endemic/typical taxa were 17%, comparable to adjacent tropical plant formations, and they were found in higher percentages in Caesalpinioideae (24%) and Cercidoideae (33%) than Papilionoideae (11%) subfamily. We also analyzed the plant diversity comparing lineages and subregions. The Gran Chaco Legumes are predominantly widespread generalists, or they belong to either Chaco sensu stricto or Neotropical Seasonally Dry Tropical Forest (SDTF) lineages. Though the Humid Chaco registered the highest species richness, Dry Chaco and Sierra Chaco, the most threatrened subregions, exhibited the highest percentages of exclusive and proper Chaco-lineage species. These results suggest that diversification of Legumes has been most relevant in Dry Chaco and Sierra Chaco, probably by their more demanding and harsh environmental conditions limiting the dispersion of generalists or intrusive-invading species. This study is paramount to reach an improved delimitation of the Gran Chaco ecoregion in transitional areas with the SDTF and Cerrado formations. Conservation status is critical in genera of high economic interest, such as Arachis, Mimosa and Prosopis. At least one third of endemic taxa exhibit a critical status of conservation or are endangered, many of them being relevant to inbreeding program or exhibiting multiple economic uses.
Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Fabaceae/classificação , Argentina , Fabaceae/crescimento & desenvolvimento , Florestas , GeografiaRESUMO
Seasonally dry tropical forests are distributed across Latin America and the Caribbean and are highly threatened, with less than 10% of their original extent remaining in many countries. Using 835 inventories covering 4660 species of woody plants, we show marked floristic turnover among inventories and regions, which may be higher than in other neotropical biomes, such as savanna. Such high floristic turnover indicates that numerous conservation areas across many countries will be needed to protect the full diversity of tropical dry forests. Our results provide a scientific framework within which national decision-makers can contextualize the floristic significance of their dry forest at a regional and continental scale.
Assuntos
Biodiversidade , Conservação dos Recursos Naturais/métodos , Florestas , Árvores , Região do Caribe , Tomada de Decisões , Pradaria , América Latina , Estações do Ano , Clima Tropical , MadeiraRESUMO
RESUMEN: En el Jardín de Aclimatación de Plantas Nativas y Medicinales FCQUNA existen 34 "ysypo" nativas, de los cuales una especie pertenece a la clase Filicopsida (helechos), cinco a la clase Liliopsida (Monocotiledóneas) y 28 corresponden a la clase Magnoliopsida (Dicotiledóneas). T otalizan 17 familias y 24 géneros. Las tres familias más importantes según el número de especies son: Passifloraceae, Bignoniaceae, y Fabaceae. Entre ellas se destacan Herreria bonplandii Lecomte y H. montevidensis Klotzsch ex Griseb., especies que figura en la lista de especies amenazadas del Paraguay . La clave para la determinación de las especies de 'ysypo' nativas del Paraguay , permitirá contar con una herramienta que facilitará su correcta identificación. Palabras clave: clave, ysypo, nativa, Paraguay
