Mandle L.,Brown University |
Mandle L.,University of Hawaii at Manoa |
Warren D.L.,University of Texas at Austin |
Hoffmann M.H.,Martin Luther University of Halle Wittenberg |
And 4 more authors.
PLoS ONE | Year: 2010
Determining the degree to which climate niches are conserved across plant species' native and introduced ranges is valuable to developing successful strategies to limit the introduction and spread of invasive plants, and also has important ecological and evolutionary implications. Here, we test whether climate niches differ between native and introduced populations of Impatiens walleriana, globally one of the most popular horticultural species. We use approaches based on both raw climate data associated with occurrence points and ecological niche models (ENMs) developed with Maxent. We include comparisons of climate niche breadth in both geographic and environmental spaces, taking into account differences in available habitats between the distributional areas. We find significant differences in climate envelopes between native and introduced populations when comparing raw climate variables, with introduced populations appearing to expand into wetter and cooler climates. However, analyses controlling for differences in available habitat in each region do not indicate expansion of climate niches. We therefore cannot reject the hypothesis that observed differences in climate envelopes reflect only the limited environments available within the species' native range in East Africa. Our results suggest that models built from only native range occurrence data will not provide an accurate prediction of the potential for invasiveness if applied to areas containing a greater range of environmental combinations, and that tests of niche expansion may overestimate shifts in climate niches if they do not control carefully for environmental differences between distributional areas. © 2010 Mandle et al.
Jestrow B.,Center for Tropical Plant Conservation |
Valdes J.J.,Center for Tropical Plant Conservation |
Valdes J.J.,Academy of Sciences of the Czech Republic |
Rodriguez F.J.,Jardin Botanico Nacional |
And 2 more authors.
Taxon | Year: 2012
Since the first collection in 1910, botanists have recognized Sarcopilea (Urticaceae) as a dramatic example of convergence with succulent woody members of Crassulaceae. Phylogenetic analyses based on nuclear ribosomal DNA ITS and the trnL-F non-coding plastid DNA regions place Sarcopilea in a Neotropical clade of Pilea. A study of the cystolith, pollen and achene morphology, and of hydathode, hydrenchyma, and stomata position was also performed, confirming the molecular results. Across Rosales, leaf succulence is restricted to the genera Pilea and Sarcopilea. Furthermore, all succulent species of Pilea have an abaxial water-storage hydrenchyma layer in their leaves, a condition unique to the genus. The conditions of adaxial stomata (epistomatic, hyperstomatic), as well as hydathodes restricted to the submarginal abaxial leaf surface, were found in all Neotropical leaf-succulent species. Carbon isotope-ratio mass spectroscopy shows Sarcopilea to have C3 photosynthesis, therefore Crassulacean acid metabolism is still unknown in Rosales. The impact of molecular systematics of Caribbean endemic genera is discussed. In light of the new phylogenetic placement of Sarcopilea, a replacement name is provided (Pilea fairchildiana).
Jestrow B.,Florida International University |
Jestrow B.,Center for Tropical Plant Conservation |
Gutierrez Amaro J.,Jardin Botanico Nacional |
Francisco-Ortega J.,Florida International University |
Francisco-Ortega J.,Center for Tropical Plant Conservation
Journal of Biogeography | Year: 2012
Aim Our aim was to investigate the historical biogeography of the three genera of the Leucocroton alliance (i.e. Garciadelia Jestrow & Jiménez Rodr., Lasiocroton Griseb., and Leucocroton Griseb., Euphorbiaceae). Location The alliance is restricted to the Bahamas, Cuba, Hispaniola and Jamaica. Methods Members of the Leucocroton alliance, along with representatives from tribe Adelieae (Adelia L. and Philyra Klotzsch.), were included in a molecular phylogenetic analysis based upon nucleotide sequences of the internal transcribed spacer region of the nuclear ribosomal DNA and the non-coding chloroplast regions psbM-trnD and ycf6-pcbM. The program s-diva was used to calculate ancestral areas based on the phylogenetic trees and present species distributions. Results Phylogenetic analyses support the monophyly of the three genera. The ancestral area of the Leucocroton alliance is eastern Cuba and Hispaniola. Ancestral forms of Leucocroton arose on eastern Cuba and underwent two migrations across the island. The ancestor of Lasiocroton also originated on eastern Cuba followed by later dispersal to and speciation events on the other islands. Our study also suggests that ancestral forms of the Leucocroton alliance probably occurred on limestone soils. Main conclusions Our study concurs with previous hypotheses suggesting that the flora of serpentinite regions of the Caribbean derives from other types of soils. The serpentine endemics of the Leucocroton alliance have a single origin and represent one of the most extraordinary examples of speciation in this unique environment of the New World. The high colonization success achieved by the members of Leucocroton on serpentine soils was not attained by the other genera of the alliance, which occur on limestone areas. © 2011 Blackwell Publishing Ltd.