Polylepis incarum (Rosaceae) una especie En Peligro Crítico en Bolivia: Propuesta de reclasificación en base al área de ocupación y estructura poblacional
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Ecología en Bolivia
Abstract
Polylepis incarum (Rosaceae) es una especie endémica de la cuenca del Lago Titicaca que se caracteriza por formar bosques monoespecíficos distribuidos en laderas montañosas. En Bolivia, la especie está clasificada como En Peligro y se estima que cubre un área aproximada de 367 km², sin embargo no existe información cuantitativa sobre su distribución actual ni el estado de conservación de las poblaciones remanentes. En este estudio realizamos una intensa y sistemática evaluación para reevaluar el estado de conservación de la especie en Bolivia. Los objetivos del estudio fueron: a) identificar los bosques remanentes y cuantificar el área de ocupación (AOO), b) evaluar la estructura poblacional de los bosques y las amenazas a las que se encuentran sujetas y c) cuantificar la regeneración de estos bosques en base a la densidad de plántulas e individuos reproductivos y el banco de semillas. Registramos un total de 20 localidades donde se encuentra P. incarum, de los cuales sólo cinco son bosques. Encontramos que actualmente la especie sólo cubre un área total de 45.12 ha, correspondiente al 0.123% del área previamente estimada. La mayoría de los bosques presentaron alta densidad de plántulas (promedio: 17.68, rango: 0.43-38.35), sugiriendo potenciales altas tasas de regeneración. El estudio del banco de semillas mostró una mayor densidad de semillas en zonas debajo del dosel (0.56 ± 0.12 semillas/g de suelo) en comparación a las zonas abiertas (0.015 ± 0.013 semillas/g de suelo) así como un incremento en la densidad de semillas a medida que aumenta la densidad de individuos reproductivos. Debido a la reducida distribución actual de P. incarum, sugerimos reclasificar a la especie como En Peligro Crítico para Bolivia y la inmediata implementación de proyectos de conservación y restauración para poder coadyuvar a la recuperación de las poblaciones remanentes y así asegurar la recuperación de la especie.
Polylepis incarum (Rosaceae) is an endemic species of the Titicaca Lake basin that forms monospecific forest stands distributed in mountain slopes. In Bolivia, the species is classified as Endangered and it is estimated that the species covers approximately 367 km²; however, there is no quantitative information regarding the conservation status of the remaining populations. In this study, we conducted an intensive and systematic field evaluation to assess the conservation status of P. incarum in Bolivia. The objectives of the study were: a) to identify remaining P. incarum forest stands and to quantify the area of occupancy (AOO), b) to evaluate the population structure of forest stands and the effects of human activities, and c) to quantify the regeneration of these forest stands based on the density of seedlings and reproductive individuals and seed bank. We registered 20 localities where P. incarum is found, from which only five represent forest stands. The species covers an estimated area of 45.12 ha, which corresponds to only 0.123% of the previously estimated area. Most of the forest stands exhibit a high density of seedlings (mean: 17.68, range: 0.43-38.35), suggesting potentially high rates of regeneration. The seed bank assessment showed high seed density in areas located under the canopy (0.56 ± 0.12 seeds/g of soil) as opposed to open areas (0.015 ± 0.013 seeds/g of soil). Due to the small distributional range of P. incarum, we suggest reclassifying the species as Critically Endangered in Bolivia as well as the immediate implementation of conservation programs in order to promote the recuperation of the remaining populations and thus ensure the recovery of the species.
Polylepis incarum (Rosaceae) is an endemic species of the Titicaca Lake basin that forms monospecific forest stands distributed in mountain slopes. In Bolivia, the species is classified as Endangered and it is estimated that the species covers approximately 367 km²; however, there is no quantitative information regarding the conservation status of the remaining populations. In this study, we conducted an intensive and systematic field evaluation to assess the conservation status of P. incarum in Bolivia. The objectives of the study were: a) to identify remaining P. incarum forest stands and to quantify the area of occupancy (AOO), b) to evaluate the population structure of forest stands and the effects of human activities, and c) to quantify the regeneration of these forest stands based on the density of seedlings and reproductive individuals and seed bank. We registered 20 localities where P. incarum is found, from which only five represent forest stands. The species covers an estimated area of 45.12 ha, which corresponds to only 0.123% of the previously estimated area. Most of the forest stands exhibit a high density of seedlings (mean: 17.68, range: 0.43-38.35), suggesting potentially high rates of regeneration. The seed bank assessment showed high seed density in areas located under the canopy (0.56 ± 0.12 seeds/g of soil) as opposed to open areas (0.015 ± 0.013 seeds/g of soil). Due to the small distributional range of P. incarum, we suggest reclassifying the species as Critically Endangered in Bolivia as well as the immediate implementation of conservation programs in order to promote the recuperation of the remaining populations and thus ensure the recovery of the species.
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Vol. 52, No. 2