Oleas Gallo, Nora Helena
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Preferred name
Oleas Gallo, Nora Helena
Main Affiliation
Quito
Email
noraoleas@uti.edu.ec
ORCID
Scopus Author ID
12645534600

Research Output
Now showing 1 - 5 of 5
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Population Dynamics of the Endangered Plant, Phaedranassa tunguraguae, from the Tropical Andean Hotspot

2012 , Oleas Gallo, Nora Helena , Meerow A.W. , Francisco-Ortega J.

The Tropical Andes is a diversity hotspot for plants, but there is a scant knowledge about patterns of genetic variation within its constituent species. Phaedranassa tunguraguae is an IUCN endangered plant species endemic to a single valley in the Ecuadorian Andes. We estimate the levels of genetic differentiation across the geographic distribution of P. tunguraguae using 12 microsatellite loci. We discuss factors that might influence the genetic structure of this species. Genetic distance was used to evaluate relationship among populations and geographic patterns. Bayesian methods were used to investigate population structure, migration, evidence of recent bottlenecks, and time of divergence. The 7 populations form 2 genetic clusters. These clusters show highly significant differentiation between them, along with isolation by distance. Allele richness decreases from the most diverse westernmost population to the least diverse easternmost population. The species overall shows an excess of homozygotes, with highest levels of inbreeding in the easternmost population. We found evidence of recent bottleneck events. Migration rates were in general low but were higher between populations within each of the clusters. Time of divergence between populations was related to historical volcanic activity in the area. Based on our results, we propose 2 management units for P. tunguraguae. © The American Genetic Association. 2012. All rights reserved.

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Molecular Systematics of Threatened Seed Plant Species Endemic in the Caribbean Islands

2013 , Oleas Gallo, Nora Helena , Jestrow B. , Calonje M. , Peguero B. , Jiménez F. , Rodríguez-Peña R. , Oviedo R. , Santiago-Valentín E. , Meerow A.W. , Abdo M. , Maunder M. , Griffith M.P. , Francisco-Ortega J.

A review of available Caribbean Island red-lists species (CR and EN categories based on the IUCN guidelines from 2001, and E category established according to the IUCN guidelines from 1980) is presented. A database of over 1,300 endemic species that are either Critically Endangered or Endangered sensu IUCN was created. There are molecular systematic studies available for 112 of them. Six of these species (in six genera) are the only members of early divergent lineages that are sister to groups composed of a large number of clades. Seven of the species (in seven genera) belong to clades that have a small number of taxa but are sister to species/genus-rich clades. Ten of the species (in six genera) are sister to taxa restricted to South America or nested in clades endemic to this region. Fifty-seven of the species (in 35 genera) are sister to Caribbean Island endemic species. Erigeron belliastroides, an Endangered (EN) Cuban endemic, is sister to the Galapagos genus Darwiniothamnus. The phylogenetic placement of four of the threatened species resulted in changes in their taxonomic placement; they belong to polyphyletic or paraphyletic genera. © 2013 The New York Botanical Garden.

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Molecular Markers and Conservation of Plant Species in the Latin-America: The Case of Phaedranassa viridiflora (Amaryllidaceae)

2013 , Oleas Gallo, Nora Helena , Meerow A.W. , Francisco-Ortega J.

Phaedranassa viridiflora (Amaryllidaceae) is an endemic and endangered plant restricted to the Northern Andes in Ecuador. It is known in three locations where it is sympatric with other Phaedranassa species. Phaedranassa viridiflora is the only species of the genus with yellow flowers. We analyzed 13 microsatellite loci to elucidate the genetic structure of the populations of P. viridiflora. Our results provided the first evidence of natural hybridization in the genus (between P. viridiflora and P. dubia in the Pululahua crater of northern Ecuador). The central and southern populations did not show hybridization. Genetic diversity was the highest in the Pululahua population. Central and southern populations have a higher proportion of clones than Pululahua. Bayesian and cluster analysis suggest that the yellow flower type evolved at least three times along the Ecuadorean Andes. In contrast to other Phaedranassa species, Phaedranassa viridiflora shows lower genetic diversity, which is likely related to a vegetative reproductive strategy. © 2013 The New York Botanical Garden (outside the USA).

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Muddy boots beget wisdom: Implications for rare or endangered plant species distribution models

2019 , Oleas Gallo, Nora Helena , Feeley K.J. , Fajardo J. , Meerow A.W. , Gebelein J. , Francisco-Ortega J.

Species distribution models (SDMs) are popular tools for predicting the geographic ranges of species. It is common practice to use georeferenced records obtained from online databases to generate these models. Using three species of Phaedranassa (Amaryllidaceae) from the Northern Andes, we compare the geographic ranges as predicted by SDMs based on online records (after standard data cleaning) with SDMs of these records confirmed through extensive field searches. We also review the identification of herbarium collections. The species' ranges generated with corroborated field records did not agree with the species' ranges based on the online data. Specifically, geographic ranges based on online data were significantly inflated and had significantly different and wider elevational extents compared to the ranges based on verified field records. Our results suggest that to generate accurate predictions of species' ranges, occurrence records need to be carefully evaluated with (1) appropriate filters (e.g., altitude range, ecosystem); (2) taxonomic monographs and/or specialist corroboration; and (3) validation through field searches. This study points out the implications of generating SDMs produced with unverified online records to guide species-specific conservation strategies since inaccurate range predictions can have important consequences when estimating species' extinction risks. © 2019 by the authors.

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Using species distribution models as a tool to discover new populations of Phaedranassa brevifolia Meerow, 1987 (Liliopsida: Amaryllidaceae) in Northern Ecuador

2014 , Oleas Gallo, Nora Helena , Meerow A.W. , Feeley K.J. , Gebelein J. , Francisco-Ortega J.

Phaedranassa brevifolia Meerow (1987) is an endangered plant species endemic to Ecuador. Until recently, this species was only known by the type location and four other adjacent subpopulations in a restricted area of less than four km2. We combined geo-referenced occurrences of this species and bioclimatic variables to generate a prospective species distribution model. Using the resulting map as a guide for field work, we found three new populations of P. brevifolia, increasing its geographic distribution to 16 km2. © 2014 Check List and Authors.

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