Reintroduction of Cattleya intermedia Graham (Orchidaceae) at the edge and interior of a Seasonal Semideciduous Forest fragment in Southern Brazil

Abstract

Habitat fragmentation threatens the maintenance of epiphytes in forest remnants, and reintroduction of such species is a tool for their conservation. The aim of this study was to monitor the reintroduction of plantlets of the epiphytic orchid Cattleya intermedia Graham at the edge and interior of a Seasonal Semideciduous Forest fragment in the municipality of Campo Bom, Rio Grande do Sul state, Brazil. Plantlets obtained through in vitro propagation were acclimatized at 26 °C and fixed to the phorophytes in the spring of 2011 and monitored for 720 days. Survival was evaluated on a monthly basis. Shoot height and the number of leaves per plantlet were assessed prior to reintroduction and subsequently on a quarterly basis. Meteorological variables were also assessed on a quarterly basis, at the edge and interior of the forest fragment. Mann-Whitney and Kruskal-Wallis tests were used (p < 0.05) to compare data between the two environments and to evaluate plantlet development in each environment. Plantlet survival was 60.23%, with no significant difference between the environments. There was a significant reduction in the number of leaves and in shoot height at the edge, which was not observed at the fragment interior. At 720 days after reintroduction, a higher percentage of plantlets developed roots on phorophytes at the edge than those at the fragment interior (50.85 and 17.02%, respectively). Luminosity and relative air humidity differed significantly between the environments. Continued monitoring and the incorporation of additional parameters will contribute to the determination of the reintroduction requirements, so that reintroduction can be used as a successful tool in conservation initiatives.