Guidelines designed to aid in the restoration of rare species have been previously proposed using... more Guidelines designed to aid in the restoration of rare species have been previously proposed using two primary strategies to select individuals for augmentation and reintroduction: mixing progeny from different populations or separating individuals from different populations. Understanding the genetic structure and diversity of an endangered species can offer insights into conservation management strategies. We used random amplified polymorphic DNA markers to assess the genetic structure and diversity of Jacquemontia reclinata, a federally endangered species endemic to Southeastern Florida. We sampled 20 percent of total number of individuals from eight of the ten known wild populations. Across individuals high levels of polymorphic loci (94.7%) were found and larger populations had greater genetic diversity. Cluster and ordination analyses found that one population was genetically differentiated from all the others; this population grows in a unique habitat. Most genetic variation (77.5%) was found within populations, and genetic distances between populations were not explained by their geographic distances. We recommend the use of two management units in restoration programs for J. reclinata, one consisting of the genetically differentiated population and the second consisting of the other seven populations sampled.Dos estrategias diferentes para la selección de individuos se han propuesto en los programas de restauración de especies raras. La primera se basa en la mezcla de progenies de varias poblaciones, la segunda considera más adecuado el separar individuos de poblaciones diferentes. El entender la estructura y la diversidad genética de una especie amenazada puede ofrecer una gran ayuda en el establecimiento de estrategias de conservación. Usamos marcadores moleculares RAPDs para estimar la estructura y la diversidad genética de Jacquemontia reclinata, una especie considerada como amenazad por el gobierno federal de Estados Unidos de América y que es endemica del sureste de Florida. Veinte por ciento de los individuos conocidos de J. reclinata se muestrearon en ocho de las diez poblaciones conocidas de esta especie. Se encontraron un gran número de loci polimórficos (94.7%) y en general poblaciones con un alto número de individuos tienen mayores niveles de diversidad genética. Técnicas de análisis multivariante de agrupamiento y ordenación sugieren que una de las poblaciones está geneticamente diferenciada de las otras. La mayor parte de la diversidad genética se encuentra dentro de las poblaciones (77.5%) y las distancias genéticas entre poblaciones no aparecen correlacionadas por sus distancias geográficas. Se recomienda el uso de dos unidades de manejo en programas de restauración de J. reclinata, una de ellas formada por la población que se ha diferenciado geneticamente de las otras, la segunda formada pr el resto de las siete poblaciones estudiadas.
ABSTRACT Subtropical coastal sand dune ecosystems have been greatly altered by agricultural use, ... more ABSTRACT Subtropical coastal sand dune ecosystems have been greatly altered by agricultural use, invasive exotic encroachment, urban development, and beach raking, rendering several plant species endangered or threatened. Restoration planning of this ecosystem will benefit from a comprehensive study on how environmental variables change across the coast to inland gradient of this ecosystem and it is therefore presented here. We also examined the relationship between the environmental characteristics and plant species composition across the gradient. We used the two largest extensions of remaining dune ecosystem on the southeastern coast of Florida, where relatively intact populations of endangered species occur. Vegetation and environmental data were collected from 97 3 x 8 m plots in two sand dune parks along the coast–inland gradient. Soil moisture, most nutrients, cation exchange capacity, and organic matter accumulation increased with distance from the coast, whereas pH and salt spray decreased. The number of species per plot was higher at further distances from the coast at one site only, and higher woody cover was associated with less species diversity at the other site. Canonical correspondence analysis revealed the importance of P, Mg, Ca, pH, cation exchange capacity, organic matter, estimated nitrogen release, and salt spray in affecting vegetation zonation. We conclude that soil chemistry is the most determinant factor of community zonation in these subtropical dunes. Restoration planning should be site specific because of the differences in environmental factors between the two study sites.
Guidelines designed to aid in the restoration of rare species have been previously proposed using... more Guidelines designed to aid in the restoration of rare species have been previously proposed using two primary strategies to select individuals for augmentation and reintroduction: mixing progeny from different populations or separating individuals from different populations. Understanding the genetic structure and diversity of an endangered species can offer insights into conservation management strategies. We used random amplified polymorphic DNA markers to assess the genetic structure and diversity of Jacquemontia reclinata, a federally endangered species endemic to Southeastern Florida. We sampled 20 percent of total number of individuals from eight of the ten known wild populations. Across individuals high levels of polymorphic loci (94.7%) were found and larger populations had greater genetic diversity. Cluster and ordination analyses found that one population was genetically differentiated from all the others; this population grows in a unique habitat. Most genetic variation (77.5%) was found within populations, and genetic distances between populations were not explained by their geographic distances. We recommend the use of two management units in restoration programs for J. reclinata, one consisting of the genetically differentiated population and the second consisting of the other seven populations sampled.Dos estrategias diferentes para la selección de individuos se han propuesto en los programas de restauración de especies raras. La primera se basa en la mezcla de progenies de varias poblaciones, la segunda considera más adecuado el separar individuos de poblaciones diferentes. El entender la estructura y la diversidad genética de una especie amenazada puede ofrecer una gran ayuda en el establecimiento de estrategias de conservación. Usamos marcadores moleculares RAPDs para estimar la estructura y la diversidad genética de Jacquemontia reclinata, una especie considerada como amenazad por el gobierno federal de Estados Unidos de América y que es endemica del sureste de Florida. Veinte por ciento de los individuos conocidos de J. reclinata se muestrearon en ocho de las diez poblaciones conocidas de esta especie. Se encontraron un gran número de loci polimórficos (94.7%) y en general poblaciones con un alto número de individuos tienen mayores niveles de diversidad genética. Técnicas de análisis multivariante de agrupamiento y ordenación sugieren que una de las poblaciones está geneticamente diferenciada de las otras. La mayor parte de la diversidad genética se encuentra dentro de las poblaciones (77.5%) y las distancias genéticas entre poblaciones no aparecen correlacionadas por sus distancias geográficas. Se recomienda el uso de dos unidades de manejo en programas de restauración de J. reclinata, una de ellas formada por la población que se ha diferenciado geneticamente de las otras, la segunda formada pr el resto de las siete poblaciones estudiadas.
ABSTRACT Subtropical coastal sand dune ecosystems have been greatly altered by agricultural use, ... more ABSTRACT Subtropical coastal sand dune ecosystems have been greatly altered by agricultural use, invasive exotic encroachment, urban development, and beach raking, rendering several plant species endangered or threatened. Restoration planning of this ecosystem will benefit from a comprehensive study on how environmental variables change across the coast to inland gradient of this ecosystem and it is therefore presented here. We also examined the relationship between the environmental characteristics and plant species composition across the gradient. We used the two largest extensions of remaining dune ecosystem on the southeastern coast of Florida, where relatively intact populations of endangered species occur. Vegetation and environmental data were collected from 97 3 x 8 m plots in two sand dune parks along the coast–inland gradient. Soil moisture, most nutrients, cation exchange capacity, and organic matter accumulation increased with distance from the coast, whereas pH and salt spray decreased. The number of species per plot was higher at further distances from the coast at one site only, and higher woody cover was associated with less species diversity at the other site. Canonical correspondence analysis revealed the importance of P, Mg, Ca, pH, cation exchange capacity, organic matter, estimated nitrogen release, and salt spray in affecting vegetation zonation. We conclude that soil chemistry is the most determinant factor of community zonation in these subtropical dunes. Restoration planning should be site specific because of the differences in environmental factors between the two study sites.
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Papers by Julissa Roncal