Genetic diversity of reintroduced tree populations of Casearia sylvestris in Atlantic forest restoration sites

The restoration projects in the Brazilian Atlantic Forest have shown more concern about genetic variability in floristic diversity in the last years. To create effective conservation policies, we need extensive knowledge on structures and patterns of genetic variation between natural populations and within them. We characterized the genetic population of Casearia sylvestris Swartz in an area under forest restoration processes (Iracemapolis, Sao Paulo) established between 1988 and 1990, and compared it to a natural remnant of semi-deciduous seasonal forest (Caetetus, Sao Paulo). The distance between locations is similar to 210 km. One hundred twenty-eight adult plants were collected, 64 individuals in the native forest remnant and 64 in the restored fragment. The genetic data were generated by the screening of six AFLP primers combinations with a total of 296 loci for each population. The forest restoration site presented overall higher levels of genetic diversity compared to the natural remnant area. The most likely number of genetic clusters found was three (K = 3). The genetic variation was higher within populations, either in the natural or restored site, than between populations. Farther, 25 candidate outlier loci were selected and separated into two groups giving support to future research with species adaptation in these different environments. Our results show that evaluation of restored tree populations of C. sylvestris is crucial to monitoring long-term restoration programs and understand if they persist over time. We hope that our results aim at species management and the establishment of others restoration projects.

Automated summary

The study focuses on restoration projects in the Brazilian Atlantic Forest, revealing higher genetic diversity in restored locations compared to natural remnants and higher genetic variation within populations than between populations in different environments. The evaluation of restored tree populations of C. sylvestris is crucial for monitoring long-term restoration programs.