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| Author(s): |
Aneliza de Almeida Miranda Melo
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2009-03-27 |
| Examining board members: |
Flavio Antonio Maës dos Santos;
Rafael Silva Oliveira;
Ricardo Ribeiro Rodrigues;
Eduardo van den Berg;
Adriana Maria Zanforlin Martini
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| Advisor: | Flavio Antonio Maës dos Santos |
| Abstract | |
One of the basic issues in ecology is to try to understand which are and on which scales the environmental factors influence the distribution of species. Thus, the spatial variations of the trees-shrubs species distribution and diversity, as well as their relationship with environmental factors (soil humidity, soil physiochemical properties, topography and light conditions in the forest) were studied on different scales, in the Ciliar Forests of the microbasins of the Brejinho (16°52'51"-16°53'05"8; 43°32'56"- 43°33'52"W) and Piedosa rivers (16°51'42"-16°52'14"8; 43°31'54"- 43°31 '55"W) , and among these microbasins. The floristic composition and environmental variables were measured in the period of January/2005 to March/2006 in 26 plots of 20 x 30 m per microbasin, distant from one another from 17 to 711 m, in the spring-mouth direction, and about 2,120 m among microbasins. In Chapter 1, there was a temporal difference in soil humidity and light among the seasons in the respective microbasins, but the temporal differences in each area did not affect the difference relationships in space. Local topographic variations, as well as soil texture, were responsible for the heterogeneity of the environmental resources available on different scales, once fertility and humidity were correlated to these factors, regional, among microbasins, and along the microbasin. That environmental variation was not always related to the gradients established between the spring and the mouth of the rivers, being also found among the riverbanks. Moreover, the samples in the same community were more similar among one another than those from different communities, despite occupying the same site in the spring-mouth topographic gradient. In Chapter 2, in general, the topographic variations, as well as factors interconnected with them, such as fertility and humidity, were responsible for the vegetation structure and species distribution on local and regional scale. Thus, the ecological patterns which occur on small scales resulting from local environmental variations are likely to be the determinants of the distribution of species local and regionally. In Chapter 3, the diversity among the parcels and banks in the same microbasin, i.e., locally, were those that contributed the most to the total diversity. Therefore, the diversity patterns observed on smaller scales determine the pattern observed on larger scales, and the diversity on larger scale, regional, is dependent on the local ecological processes, such as environmental variability, resulting in variation of the species composition among the sites, where the topographic variability, and also the texture, and factors correlated with them, such as humidity, were responsible for the diversity. Therefore, only through studies on different scales it is possible to identify the action scale and/or the reach of the effects of the local variability" as well as to know which environmental factors are related to the species distribution and diversity. (AU) | |