Contributions of local adaptations and plasticity of seeds and seedlings for the occurrence of Euterpe edulis and Syagrus romanzoffiana in three forest types from São Paulo State

Author(s)

Pedro Henrique Santin Brancalion

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2009-12-16

Examining board members

Ricardo Ribeiro Rodrigues; Giselda Durigan; Dalva Maria da Silva Matos; Giancarlo Conde Xavier Oliveira; Rafael Silva Oliveira

• Advisor: Ricardo Ribeiro Rodrigues; Ana Dionisia da Luz Coelho Novembre

Abstract

Species with wide geographical and ecological distribution may have local adaptations as consequence of the differentiated and specific selective pressures in each occupied habitat, originating ecotypes. Although contributing for adaptations identification and quantification in evolutionary studies, researches about ecotypes formation may be fundamental for the success of tropical forest conservation and restoration ecology. Therefore, this work was conducted with the objective of evaluating the contributions of local adaptation and plasticity in seeds and seedlings for the occurrence of the palm species Euterpe edulis and Syagrus romanzoffiana in permanent parcels inserted in different forest types of the São Paulo State. It were studied E. edulis populations growing in the Seasonally Dry Forest of the Estação Ecológica dos Caetetus, in the Atlantic Rainforest of the Parque Estadual de Carlos Botelho and in the Restinga Forest of the Parque Estadual da Ilha do Cardoso, and S. romanzoffiana populations growing in the Seasonally Dry Forest and Restinga Forest areas and in the Cerradão of the Estação Ecológica de Assis. It were evaluated seed size, seed crop, seed development and seed germination for populations of both species, S. romanzoffiana pre-dispersal seed predation by the weevil Revena rubiginosa and contributions of local adaptation and plasticity, in experiments of common garden and reciprocal transplants, in E. edulis seedling establishment and in juveniles growth of both species. There were significant variation in seed size and crop among populations of both species and between the years 2008 and 2009 for E. edulis, despite remarkable differences in seed development and germination of those seeds. S. romanzoffiana seed predation reached around 70% in all forest types, and rodents did not discriminate between sound and weevil infested endocarps while predating seeds in the post-dispersal phase. The occurrence of E. edulis in the Atlantic Rainforest and in the Seasonally Dry Forest is enhanced by the presence of local adaptations for seedling establishment, but its occurrence in the Restinga Forest is enhanced by local adaptation for juveniles growth. Although local adaptations for S. romanzoffiana juveniles growth had not been observed in the reciprocal transplant, the individuals produced in the common garden with seeds from Cerradão showed higher shoot, leaf blade and entire juvenile dry mass values than juveniles of the other provenances, indicating the existence of adaptive genetic divergence. Hence, both E. edulis and S. romanzoffiana need to overcome specific limitations for the reproduction in the studied forest types. These limitations are probably a result of the main selective pressures present in these different habitats, which may have resulted in the origin of ecotypes and growth differences. Hence, such results indicate that tree species seeds and seedlings should be collected and used in the same forest type subjected to conservation and restoration ecology efforts, given the evidences of local adaptations for both species. (AU)