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| Author(s): |
Aline Luisa Mansur
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: | 2017-01-09 |
| Examining board members: |
Flavio Antonio Maës dos Santos;
Maíra de Campos Gorgulho Padgurschi;
Sergius Gandolfi
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| Advisor: | Flavio Antonio Maës dos Santos |
| Abstract | |
Seasonal Semideciduous Forests (SSF) is one of the phytophysiognomies of Atlantic Forest where 30 to 50 % of trees lose totally or partially their leaves during the dry season, which may extend from April to September. Leaf fall causes an increase in light availability under deciduous canopies and solar irradiance in these areas may be up to 24 times higher than under evergreen canopies. Solar irradiance under deciduous canopies in that period is similar to solar irradiance found in treefall gap areas and are called deciduousness gaps: understory regions where light levels are greater when compared to areas under evergreen canopies. This study aim to investigate if deciduousness gaps are key factors in determining structure and composition of SSF. In order to evaluate how canopy openness vary over the year under evergreen and deciduous canopies we took hemispherical photos under 24 trees classified as deciduous, 55 classified as semidecidous and 54 classified as evergreen. To assess whether deciduousness gaps affect vegetation structure and composition we used understories under overstory trees whose crowns were not covered by any other tree crown (focal tree) as sample unit. We sampled shrub and tree individuals from 1 m height under 83 deciduous canopies and 59 evergreen canopies. We also measured growth of 33 plants (Diameter at Breast Height > 5 cm) under deciduous canopies and 30 plants under evergreen canopies each three months. We did not find differences in canopy openness values under canopies classified in different phenological groups in all periods of the year. Regarding structure and composition of plants in deciduous and evergreen understories we found differences only for small plants (Diameter at Soil Height < 5 cm). Small plants density was lower under deciduous canopies when compared to evergreen canopies, which may be related to a greater mortality brought by concentrated litter fall in deciduous understory. We did not find differences in growth rate of trees under deciduous and evergreen canopies, which may be related to the fact the light increment is similar under deciduous and evergreen understories during the period of deciduousness or to the fact that water availability is lower in this period in SSF. We conclude that, even if light entrance is not different between understory of different phenological categories during the deciduousness period, another consequences of deciduousness for understory environment, like mechanical damage to saplings, may affect small plants community structure. In this way to be under deciduous or evergreen canopies in SSF may affect future dynamics in SSF (AU) | |
| FAPESP's process: | 14/23440-9 - The influence of the gaps of deciduiusness on tree communities dynamics in seasonal semi-deciduous forests |
| Grantee: | Aline Luisa Mansur |
| Support Opportunities: | Scholarships in Brazil - Master |