Artículo de publicación ISIA high proportion of plant species is predicted to be threatened with extinction in the near future. However, the threat status of only a small number has been evaluated compared with key animal groups, rendering the magnitude and nature of the risks plants face unclear. Here we report the results of a global species assessment for the largest plant taxon evaluated to date under the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, the iconic Cactaceae (cacti). We show that cacti are among the most threatened taxonomic groups assessed to date, with 31% of the 1,478 evaluated species threatened, demonstrating the high anthropogenic pressures on biodiversity in arid lands. The distribution of threatened species and the predominant threatening processes and drivers are different to those described for other taxa. The most significant threat processes comprise land conversion to agriculture and aquaculture, collection as biological resources, and residential and commercial development. The dominant drivers of extinction risk are the unscrupulous collection of live plants and seeds for horticultural trade and private ornamental collections, smallholder livestock ranching and smallholder annual agriculture. Our findings demonstrate that global species assessments are readily achievable for major groups of plants with relatively moderate resources, and highlight different conservation priorities and actions to those derived from species assessments of key animal groupsConsejo Nacional de Ciencia y Tecnologia
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Premise
Although numerous phylogenetic studies have been conducted in Cactaceae, whole‐plastome datasets have not been employed. We used the chollas to develop a plastome dataset for phylogeny reconstruction to test species relationships, biogeography, clade age, and morphological evolution.
Methods
We developed a plastome dataset for most known diploid members of the chollas (42 taxa) as well as for other members of Cylindropuntieae. Paired‐end, raw reads from genome skimming were reference‐mapped onto a de novo plastome assembly of one species of cholla, Cylindropuntia bigelovii, and were used to build our plastome dataset, which was analyzed using various methods.
Results
Our plastome dataset resolved the phylogeny of the chollas, including most interspecific and intraspecific relationships. Tribe Cylindropuntieae arose ~18 mya, during the early Miocene in southern South America, and is supported as sister to the South American clade Tephrocacteae. The (Micropuntia (Cylindropuntia + Grusonia)) clade most likely originated in the Chihuahuan Desert region around 16 mya and then migrated into other North American desert regions. Key morphological characters for recognizing traditional taxonomic series in Cylindropuntia (e.g., spiny fruit) are mostly homoplasious.
Conclusions
This study provides the first comprehensive plastome phylogeny for any clade within Cactaceae. Although the chollas s.l. are widespread throughout western North American deserts, their most recent common ancestor likely arose in the Chihuahuan Desert region during the mid‐Miocene, with much of their species diversity arising in the early to mid‐Pliocene, a pattern strikingly similar to those found in other western North American desert groups.
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