Full text
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| Author(s): |
Ligia Paulillo Sims
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2009-04-08 |
| Examining board members: |
Fernando Roberto Martins;
Kikyo Yamamoto;
Tereza Cristina Souza Sposito
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| Advisor: | Fernando Roberto Martins |
| Abstract | |
the present study investigated the ontogenetic and spatial structure of the tree species Savia dictyocarpa (Phyllanthaceae) in the Mata Ribeirão Cachoeira, Campinas municipality, SP. This is a dioecious species that commonly occur on seasonal forest canopy from southeast region of Brazil, and because of its importance we decided to gather information about its life history. To do that, we ask two main questions: 1) Can we define S. dictyocarpa ontogenetic stages using morphometric and architectural variation along the species life? ; 2) Which is the spatial distribution of different ontogenetic stages and which are the environmental factors that influence this distribution? We sampled 0,5 hectares and found 194 individuals distributed in 5 ontogenetic stages: infant, juvenile, immature and adult and senile. We did not found seedlings or reproductive adults in the plots we sampled, but we found some fruits and seedlings on the trail. Thus, seedling stage was described with no consideration of morphometric characteristics. The fruits we found did not have seeds and this fact indicates the absence of flower pollination, which could be caused by low frequency of male individuals or by absence of pollinator. The ramification pattern showed by S. dictyocarpa is correspondent to Massart architectural model, which is common for species that grow under low light conditions. Stages presented significant differences in height and diameter. Juvenile and immature presented smaller diameter increment per unit of height, and adult stage had higher diameter increment per unit of height. This suggests that in early stages a greater investment in height allows then to quickly reach for good light conditions on the forest canopy, disregarding the mechanical stability. We also found that crown length investment per unit of crown width increase along ontogeny, what shows that there is differences between stages to increase the light absorption efficiency. Liana infestation seems to affect adult crown development because individuals with liana have smaller investment in crown length. All stages presented random spatial distribution and juvenile and immature showed the tendency to occupy the same places, probably because they have the same recruitment and growth requirements. All correlations between stages and abiotic and biotic factors (light, soil and interspecific competition) were spurious or nom significant. This random pattern could be explained by environmental characteristics that were not considered here or by stochastic processes. Species distribution could also be strongly affected by seed, seedling or infant distributions, which were not found in the sampled area. These results suggests that there are different environmental occupation and resource use strategies along a canopy species live, however the environmental characteristics sampled here were not able to explain how this strategies determinates recruitment patterns in the space. To understand the absence of seeds and seedlings in the area and to propose conservation and management plans for S. dictyocarpa, reproductive biology and population dynamic studies are required (AU) | |