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Genetic feasibility of forest restorations : genetic diversity and structure in Myroxylon peruiferum L.f

Author(s):
Kaiser Dias Schwarcz
Total Authors: 1
Document type: Doctoral Thesis
Institution: Universidade Estadual de Campinas. Instituto de Biologia
Defense date:
Examining board members:
Louis-Bernard Klaczko; Aluana Gonçalves de Abreu; Evandro Marsola de Moraes; Pedro Henrique Santin Brancalion
Advisor: Maria Imaculada Zucchi
Abstract

Ecological degradation and deforestation are processes that started long ago and whose history is intertwined with that of agriculture. Atlantic Forest is the second largest rainforest in occurrence and importance in South America, having great biological diversity and high levels of endemism. Disordered occupation of Atlantic Forest caused its reduction to 11.26% of the original area, with distribution in forest fragments poorly conected across the Brazilian territory. Destruction of the Atlantic Forest has resulted in the elimination of many populations and potentially the erosion of genetic diversity of several species. This combination of high endemism and strong threat of extinction causes the Atlantic Forest to be considered a hotspot for conservation. In the last decades recovery of degraded ecosystems has received attention from the scientific community giving birth to an new area of knowledge called the Restoration Ecology. The study and monitoring of areas of forest restoration is essential to improve restoration techniques in tropical and subtropical ecosystems. For a given species to perpetuate itself in an area undergoing a restoration process, it needs to develop its whole life cycle and generates progeny capable of developing to the point of replacing mothers trees when they die. Therefore there is a need to study the genetic variability of tree populations within areas of restored forest, as well as the occurrence and effectiveness of gene flow between these areas and surrounding fragments. We studied the genetic variability of Myroxylon peruiferum L. f., in two different areas of forest restoration and in two areas of natural remnants of semideciduous forest. Our results indicates that restorations in Cosmopolis and Iracemápolis conserve genetic and allelic diversity HE similar to that of natural remnants. The main difference between natural and restored areas was the lowest richness of endemic alleles which is the result of a sampling effect that favors the loss of rare alleles. The area of older forest restoration in Cosmopolis presented a spatial genetic structure consistent with natural areas. This did not occur with the newer restoration in Iracemápolis. We observed the occurrence of local genetic structure in natural areas and in the area of older restoration and evidence of gene flow between native and restored areas. An additional study about the effect of sampling size on allele frequencies showed the phenomenon of loss of low frequency alleles in sampling events. The same study found that a sample of about 30 individuals are able to adequately represent alleles with frequencies above 0.05; this is a good number to consider in selecting matrix trees to supply seedlings for forest restoration. (AU)

FAPESP's process: 10/00170-5 - Genetic variability os forest restorations: diversity and structure of Centrolobium tomentosum Gullim ex. Bentham e Myroxylon peruiferum L.F
Grantee:Kaiser Dias Schwarcz
Support type: Scholarships in Brazil - Doctorate