Densidade de recursos florais em múltiplas escalas espaciais: conseqüências para a interação planta-polinizador e demografia de Abutilon rufinerve (Malvaceae) / Floral resource availability in multiple hierarchical spatial scales and its consequences to plant-pollinator interaction and demography of Abutilon rufinerve (Malvaceae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Heterogeneity is a remarkable characteristic of biological systems. This thesis is about the influence of heterogeneity on plant-pollinator interaction and on demography of a tropical treelet Abutilon rufinerve. With an approach of hierarchical scales of patch structure we: 1. characterized the spatio-temporal variation on the availability of floral resources to bats and hummingbirds, the main pollinators of this species; 2. evaluated the occurrence of positive or negative density effects of A. rufinerve on pollinator attraction and seed production; and 3. elucidated the relative importance of variation in seed production to A. rufinerves demography in different environmental conditions, characterized by medium and high conspecific density. The availability of resources did not differ between day and night, against our expectations of higher nectar production by night as a result of selective pressures made by bats, the most efficient pollinators. The greatest variation in floral resources and in the response of floral visitor was observed at fine spatial scales. Abutilon rufinerves demography indicated that in this population, pollinators seem to pose no selective pressure on plants. Seed production has few effects on fitness because seedling survival and growth is the critical stage in life-cycle. However it is important to emphasize that this study reflects a short period of this population existence, and that evolutionary process vary spatio-temporaly creating geographic mosaics.

ASSUNTO(S)

pollination morcegos polinização beija-flores heterogeneidade espacial bat demografia demography hummingbird néctar spatial heterogeneity nectar resource

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