RESUMO
Poales are one of the most species-rich, ecologically and economically important orders of plants and often characterise open habitats, enabled by unique suites of traits. We test six hypotheses regarding the evolution and assembly of Poales in open and closed habitats throughout the world, and examine whether diversification patterns demonstrate parallel evolution. We sampled 42% of Poales species and obtained taxonomic and biogeographic data from the World Checklist of Vascular Plants database, which was combined with open/closed habitat data scored by taxonomic experts. A dated supertree of Poales was constructed. We integrated spatial phylogenetics with regionalisation analyses, historical biogeography and ancestral state estimations. Diversification in Poales and assembly of open and closed habitats result from dynamic evolutionary processes that vary across lineages, time and space, most prominently in tropical and southern latitudes. Our results reveal parallel and recurrent patterns of habitat and trait transitions in the species-rich families Poaceae and Cyperaceae. Smaller families display unique and often divergent evolutionary trajectories. The Poales have achieved global dominance via parallel evolution in open habitats, with notable, spatially and phylogenetically restricted divergences into strictly closed habitats.
Assuntos
Ecossistema , Poaceae , Filogenia , Evolução BiológicaRESUMO
As deforestation and fire move forward over pristine vegetation in the Amazon, many species remain undiscovered and may be threatened with extinction before being described. Here, we describe two new species of Utricularia (Lentibulariaceae) collected during recent fieldwork in an area of white-sand vegetation in the eastern Amazon Basin named Campos do Ariramba. Further herbarium revision revealed that both species were first collected over 60 years ago in the same area, remaining unnamed until now. The new species, named U. ariramba sp. nov. and U. jaramacaru sp. nov., are placed in U. sect. Aranella and U. sect. Setiscapella, respectively. We provide full descriptions, illustrations, photographs, a distribution map, and taxonomic discussion for both species. Additionally, we provide a preliminary list of Lentibulariaceae from the Campos do Ariramba. Both new species are assessed as Vulnerable, however, yet known only from a few collections each, highlighting the urgency and importance of fieldwork and taxonomic revisions in the Amazon biogeographic region in order to provide essential data for the conservation of both known and still unknown biodiversity.
RESUMO
The world's largest mineral iron province, Serra dos Carajás, is home to an open vegetation known as canga, found on top of isolated outcrops rising out of the Amazon rainforest. Over one thousand vascular plants species have been recorded in these canga sites, including 38 edaphic endemics. A new survey adds to our investigation of biogeographic relationships between sixteen canga outcrops and the effect of the distance between site pairs on the number of shared species, regional species turnover and species distribution patterns. Plant collecting expeditions to the westernmost site, the Serra de Campos of São Félix do Xingu (SFX), were carried out followed by the identification of all collected specimens and the creation of a species database, built to perform biogeographical analyses. Floristic relationships among the sites were investigated regarding their similarity, using multivariate analyses. The correlation between canga areas and species richness was tested, as well as the geographical distance between pairs of outcrops and their shared species. Vascular plants at SFX total 254 species including 17 edaphic endemics. All canga sites are grouped with 25% of minimum similarity, and the SFX falls within a large subgroup of outcrops. The total species number shared between site pairs does not change significantly with geographical distance but is positively correlated with the area of each outcrop. Meanwhile, shared endemic species numbers between site pairs decline when geographical distance increases, possibly imposed by the barrier of the rainforest. Our data suggest higher shared similarity between the largest and species-richest sites as opposed to geographically nearby sites, and provide useful insight for drafting conservation and compensation measures for canga locations. The size of the canga outcrops is associated to higher floristic diversity but connectivity among islands also plays a role in their similarity.
