ABSTRACT
Tripterygium hypoglaucum is an endangered species in arid areas of Xiannvshan Chongqing, China. The dynamic characteristics of seed rain and soil seed bank of T. hypoglaucum were studied in this paper．Results showed that T. hypoglaucum years of mature seeds distribution number up to October; the seed rain occurred from the last ten-day of September to in the first ten-day of November and the peak of scattered seed rain concentrated in the October．The numbers of soil seed bank at 2-5 cm soil layer,mainly concentrated in the 1.5-3.5 m range. T. hypoglaucum seeds to the wind as a force for transmission, the transmission ability is strong, but in the process of natural reproduction, full mature seed rate is low, the soil seed bank seeds seed short-lived factors these were unfavorable for the natural reproduction of T. hypoglaucum population.
ABSTRACT
Gaiadendron punctatum (Ruiz & Pavón) G. Don y Ternstroemia meridionalis Mutis ex L.f. son especies ornitócoras del bosque altoandino, la primera abundante en el parque natural municipal Ranchería, y la segunda rara localmente. Se evaluó la lluvia de semillas y la fenología de la fructificación de G. punctatum y T. meridionalis. El muestreo se realizó entre marzo y diciembre de 2010, período que incluye época seca y lluviosa. Se instalaron 8 trampas, con una superficie de recolección de 1 m2. La fructificación de las dos especies fue continua, con alto porcentaje de frutos inmaduros; la mayor fructificación se presentó en época lluviosa. Las dos especies presentaron lluvia de semillas durante todo el estudio, G. punctatum presentó lluvia de semillas más alta con un promedio de 169/m2, mientras que T. meridionalis presentó 50 semillas/m2. La mayor abundancia de semillas de G. punctatum se presentó en época seca, mientras que en T. meridionalis fue en época lluviosa. A pesar de la baja lluvia de semillas, T. meridionalis, mostró un porcentaje alto de semillas viables. G. punctatum presentó mayor presión de propágulos, lo que explicaría el alto número de individuos en el área. Aunque el número de semillas de T. meridionalis no es muy alto, representa un potencial para la prevalencia de esta especie y la necesidad de buscar los factores que impiden la persistencia de estos propágulos.
Gaiadendron punctatum (Ruiz & Pavon) G. Don and Ternstroemia meridionalis Mutis ex L.f. are ornithochorous species of the high-Andean forest; the first is abundant at Natural Municipal Park Rancheria, and the second rare at local level. The seed rain and fruiting phenology of G. punctatum and T. meridionalis were evaluated. Records were kept between March and December of 2010. This period included dry and wet seasons. Eight traps with a recollection surface of 1 m2 were intalled. Fruiting of G. punctatum and T. meridionalis was continued with a high percentage of unripe fruits. The higher fruiting was shown in the wet season. Both species presented seed rain during all the study. G. punctatum had higher seed rain with an average of 169/m2; while T. meridionalis only 50 seeds/m2. Most abundance of G. punctatum's seeds was recorded in the dry season, while for T. meridionalis in wet season. In spite of low seed rain for T. meridionalis it showed a high percentage of viable seeds. G. punctatum presented more propagules that could explained the high number of individuals by area. Although the number of seeds of T. meridionalis is not very high, it represents a potential for prevalence of this specie and the need of looking for factors that to block the persistence of this propagules.
ABSTRACT
O objetivo deste trabalho foi avaliar os mecanismos de regeneração natural em três agrupamentos florísticos em remanescente de Floresta Ombrófila Mista, localizado em São Francisco de Paula, RS. A coleta dos dados foi realizada em seis conglomerados de um hectare, subdivididos em 16 parcelas cada, nas quais foram coletadas amostras da chuva de sementes, do banco de sementes no solo e do banco de plântulas. Os grupos florísticos apresentaram diferenças significativas para a densidade de indivíduos na chuva de sementes e no banco de plântulas. Para o banco de sementes no solo, o grupo G1 diferiu dos grupos G2 e G3. A riqueza de espécies observada no banco de plântulas sugere que este pode ser o mecanismo principal de manutenção da diversidade no remanescente. A chuva de sementes foi abundante e representou uma fonte expressiva de propágulos para abastecer o banco de sementes e banco de plântulas local e das áreas circunvizinhas. O banco de sementes do solo não apresentou potencial florístico para representar a riqueza de espécies presentes na vegetação arbórea, corroborando o estágio sucessional avançado desta floresta, uma vez que o banco de sementes é formado principalmente de espécies pioneiras.
The aim of this study was to evaluate the natural regeneration mechanisms in three floristic groups of the remaining Mixed Rain Forest, located in San Francisco de Paula, RS. The data were collected in six conglomerates of one hectare, subdivided into 16 plots, in which seed rain, soil seed bank, and seedling bank were collected. The groups presented differences in the density of individuals in the seed rain and in the seedling banks. For the soil seed bank, the group G1 differed from the groups G2 and G3. The seedlings bank, due to the wealth of species, may be the primary mechanism for maintaining diversity in the remnant. Seed rain was abundant and represented an expressive source of seeds to supply the seed bank and the seedling bank site and surrounding areas. The seed bank of soil did not show potential to replace the floristic richness of species in the arboreal vegetation, confirming the advanced stage of forest succession, once the seed bank is composed mainly of pioneer species.
ABSTRACT
Planting seedlings is a common technique for abandoned pastures restoration in the tropics, supposedly by increasing the seedling recruitment and accelerating succession. In this study we evaluated the role of a young restored forest (one year old) in enhancing seedling establishment from two sources (seed rain and seed bank), in the Atlantic Rainforest region in Southern Brazil. We compared abandoned pasture, young restored forest and old-growth forest with respect to the seedlings recruited from different sources, by monitoring 40 permanent plots (0.5mx0.5m) over 20 months. From the three studied areas a total of 392 seedlings of 53 species were recruited. Species were mainly herbaceous (85%), pioneers (88%), zoochorous (51%) and small-seeded species (60%). Seedling recruitment from the seed bank (density and species richness) was higher and dominated by herbaceous species in the abandoned pasture and in the young restored forest; on the other hand, the recruitment of woody species from seed rain was more pronounced in the old-growth forest. The young restored forest increased the species richness of woody seedlings recruitment from the seed bank (two-fold) and from seed rain (three-fold) compared to the abandoned pasture. Also, the seedling density in young restored forest was still higher than abandoned pastures (seed bank: four times; seed rain: ten times). Our results show that even young restored areas enhance the establishment of woody species and should be considered an important step for pasture restoration. Rev. Biol. Trop. 58 (4): 1271-1282. Epub 2010 December 01.
La introducción de plántulas en pastizales abandonados es una técnica común de restauración de los bosques en los trópicos, debido a que incrementa el reclutamiento de plántulas y acelera la sucesión. En este estudio se evaluó el papel de un bosque restaurado joven (un año) en el reclutamiento de plántulas a través de dos fuentes (lluvia y banco de semillas) en la región del Bosque Atlántico en el sur de Brasil. Se comparó un pastizal abandonado, un bosque restaurado joven y un bosque secundario maduro en cuanto al reclutamiento de plántulas de diferentes fuentes, mediante el monitoreo permanente de 40 parcelas (0.5mx0.5m) durante 20 meses. En las tres áreas estudiadas se reclutaron 392 plántulas de 53 especies, principalmente herbáceas (85%), pioneras (88%), zoocoras (51%) y de semilla pequeña (60%). El reclutamiento de plántulas en el banco de semillas (densidad y riqueza de especies) fue el más alto y dominado por especies herbáceas en el pasto abandonado y en el bosque restaurado joven, el reclutamiento de especies leñosas por la lluvia de semillas fue más pronunciado en los bosques secundarios maduros. Cuando se compara con el pastizal abandonado, el bosque restaurado joven presentó una mayor riqueza de plántulas de especies leñosas reclutadas, tanto del banco (el doble) como de la lluvia de semillas (tres veces más); la densidad de plántulas en el bosque restaurado joven fue más alta que en los pastizales abandonados (cuatro veces en el banco y diez veces en la lluvia de semillas). Nuestros resultados muestran que las áreas restauradas aún jóvenes pueden aumentar el reclutamiento de especies leñosas y deben considerarse como un paso importante para la restauración de pastizales.