Rescue and translocation of Oncidium warmingii (Orchidaceae), an endangered species from ironstone rupestrian fields

Abstract

The viability of a program to rescue and translocate Oncidium warmingii (Orchidaceae), a rupestrian field endangered species, was assessed by two reintroduction methods: direct translocation of the rescued individuals to the reintroduction site and indirect translocation, i.e., previous cultivation in a greenhouse, before translocation to the reintroduction site. 29 rescued plants were monitored for 15 months to evaluate survival, growth rate (number of bulbs), and proportion of bulbs vegetatively active. At the end of the monitoring period, the plants directly translocated to the reintroduction site had higher rates of survival, growth rate and proportion of vegetatively active bulbs. The indirect translocation method was less efficient mainly in the transfer of plants from the greenhouse to the reintroduction site, indicating that it is necessary to use plant hardening techniques to ensure greater adaptation of plants when transferring from the greenhouse to the field. This species has shown good tolerance to the translocation, both directly to the environment or with previous cultivation in a greenhouse. The rescue success of O. warmingii should serve to stimulate similar actions with other endemic and endangered species in areas subjected to the development of human activities that result in the removal of native vegetation.

Key words: conservation, orchids, reintroduction, threatened species.