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1.
Rev. biol. trop ; 68mar. 2020.
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1507603

RESUMO

Introduction: Isla del Coco is the only island in the Eastern Tropical Pacific with humid tropical forests; 296 plant species are reported, of them, 22% are endemic. Their ecology is poorly understood. Deforestation and the introduction of rats, feral pigs and white-tailed deer are the primary agents of forest degradation. After more than 120 years, the deforested areas have never recovered the native forest. Objective: To analyse if the deforested area keeps its resilience, we evaluated the natural regeneration and ecological processes associated. Methods: From August 2016 to June 2018, we conducted a restoration experiment consisting of a randomized complete blocks design including vegetation cutting, vegetation uprooting and controls as treatments. Plots were protected with an exclusion fence to avoid herbivores. Results: There were no differences between plant cutting and uprooting in stimulating natural regeneration. We only recorded the seedlings of two tree species, 35 individuals of Cecropia pittieri and three of Sacoglottis holdridgei, both endemic. Their regeneration established during the first 15 months mainly. At the end of the experiment, the structure and composition of the vegetation changed from bushes dominated by Entada gigas (28%) and Clidemia strigillosa (12%) to grasses dominated by Paspalum conjugatum (39%). Entada gigas has a high recolonizing potential with a growing rate of 1.6±0.2m/month. Conclusions: As filters for restoration we determined herbivores, which pose a strong negative impact in the development of the forest; the exhausted seed bank of tree species and scarce or null seed dispersion.


Introducción: Isla del Coco es la única isla en el Pacífico oriental con bosques tropicales húmedos, albergando 296 especies de plantas, de las cuales un 22% son endémicas. De su ecología se conoce muy poco. El bosque fue degradado con la introducción de cerdos y venados cola blanca y por deforestación. Las áreas deforestadas hace más de 120 años nunca recuperaron el bosque nativo. Objetivo: Para analizar si el área deforestada mantiene su capacidad de recuperación, se evaluó la regeneración natural y los procesos ecológicos asociados. Metodología: Desde agosto de 2016 hasta junio de 2018, se monitoreó un ensayo de restauración, establecido como un diseño de bloques completos al azar. Los tratamientos incluyeron corte de vegetación, arranque de vegetación y controles. Se utilizó una cerca de exclusión para evitar los herbívoros. Resultados: No hubo diferencias en los tratamientos de corte y arranque de la vegetación para estimular la regeneración natural. Se registró la regeneración de dos especies de árboles: 35 individuos de Cecropia pittieri y tres de Sacoglottis holdridgei, ambas endémicas. La regeneración se estableció principalmente en los primeros 15 meses. Luego de aplicados los tratamientos, la estructura y composición de la vegetación cambió de arbustos dominados por Entada gigas (28%) y Clidemia strigillosa (12%), a pastos dominados por Paspalum conjugatum (39%). Entada gigas tiene el mayor potencial de recolonización por su tasa de crecimiento de 1.6±0.2m/mes. Conclusiones: Los filtros determinados asociados con la regeneración del bosque son los herbívoros; el banco de semillas de las especies arbóreas agotado y la dispersión de semillas escasa o nula, según la especie.

2.
Bol. latinoam. Caribe plantas med. aromát ; 15(1): 41-52, ene. 2016. ilus, graf, tab
Artigo em Espanhol | LILACS | ID: biblio-907516

RESUMO

Los cercos vivos urbanos tienen un rol significativo por ser reservorios de biodiversidad y por las funciones socioeconómicas que pueden sustentar. En Bariloche (Río Negro, Patagonia Argentina) se estudiaron 300 cercos familiares, la riqueza de especies leñosas componentes, sus usos medicinales y comestibles, presencia de aromaticidad, como así también su disponibilidad en comercios locales. Los cercos se componen de 86 especies, entre estas las más frecuentes son las exóticas: Cytisus scoparius, Pseudotsuga menziesii, Cupressus macrocarpa y Rosa sp., y las nativas: Chusquea culeou y Nothofagus antarctica. El 73 por ciento de las especies son medicinales, el 59 por ciento comestibles y el 33 por ciento. Solo el 24 por ciento de las especies están disponibles en comercios de la ciudad dedicados a la venta de alimentos y/o productos herbolarios. Se concluye que los cercos de Bariloche tienen un alto potencial para la complementación, diversificación de la dieta y el tratamiento de dolencias menores de los pobladores locales.


Urban hedges have a significant role to be reservoirs of biodiversity and socio-economic functions that it can sustain. In Bariloche (Río Negro, Patagonia Argentina) we studied 300 family hedges, the richness of woody components, their medicinal and edible uses, presence of aromaticity, as well as their availability in local stores. The hedges are composed of 86 species, among these the most common are the exotics: Cytisus scoparius, Pseudotsuga menziesii, Cupressus macrocarpa y Rosa sp., and the natives: Chusquea culeou and Nothofagus antarctica. 73 percent of these one are medicinal, 59 percent are edible and 33 percent are aromatic plants. Only 24 percent of the species are available in shops of the city dedicated to the sale of food and/or herbal products. We conclude that the hedges of Bariloche have a high potential for supplementation, dietary diversification, and treatment of minor ailments of the local people.


Assuntos
Etnobotânica , Plantas Comestíveis , Plantas Medicinais , Argentina , Biodiversidade , Área Urbana
3.
Conserv Biol ; 21(1): 232-40, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17298529

RESUMO

Deforestation of temperate forests has created landscapes of forest remnants in matrices of intense human use. We studied the genetic effects of fragmentation in southern Chile on Embothrium coccineum J.R. et G. Forster, an early colonizing, bird-pollinated tree. We tested the hypothesis that, because of its self-incompatibility and life-history strategy, E. coccineum is less strongly affected by fragmentation. We studied the effects of reduced population size and increased isolation on population genetic structure and early performance of progeny. Samples were collected from spatially isolated trees and six fragments of differing sizes (small, 1 ha; medium, 20 ha; large, >150 ha). Based on isozyme polymorphisms we estimated parameters of genetic diversity, divergence, and inbreeding for adults and greenhouse-grown progeny. We also measured germination, seedling growth, and outcrossing rates on progeny arrays. Genetic variation of adults did not correlate significantly with population size, as expected, given that fragmentation occurred relatively recently. Weak effects of fragmentation were measured on progeny. Only adults yielded significant inbreeding. Similar total genetic diversity was found in adults and progeny. Low but significant genetic differentiation existed among adult and progeny populations. Seedling growth correlated positively with the effective number of alleles, showing deleterious effects of inbreeding on progeny. Seeds from small fragments had the highest outcrossing rates and germination success, indicating that higher pollinator activity in such fragments reduced selfing, thereby buffering genetic erosion and maintaining adaptive variation. The effects of forest fragmentation were detectable in E. coccineum, but these effects will probably not be detrimental to the viability of remnant populations because small, fragmented populations demonstrated higher levels of gene flow and lower inbreeding than larger stands. Pioneer species that are insensitive to forest clearing may be crucial in recovery plans to facilitate the establishment of species intolerant to such disturbance.


Assuntos
Conservação dos Recursos Naturais , Variação Genética , Genética Populacional , Endogamia , Proteaceae/genética , Plântula/crescimento & desenvolvimento , Árvores , Chile , Isoenzimas/genética , Densidade Demográfica
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