REINTRODUCTION OF Oncidium sphacelatum Lindl. (ORCHIDACEAE) INTO A SHADED COFFEE PLANTATION

Abstract

Epiphytic orchids face high mortality rates following reintroduction attempts, largely because habitat loss and fragmentation reduce the number of microsites and phorophytes available for their establishment. Reintroduction into agroecosystems with tree cover has emerged as a complementary conservation strategy. However, predictors of successful establishment of epiphytic orchids in traditional coffee plantations have been poorly evaluated. The objective of this study was to evaluate the effects of the number of initial pseudobulbs and the height at which the plant was attached to the host tree on the survival and vegetative growth of Oncidium sphacelatum Lindl. reintroduced into a shade-grown coffee plantation in central Veracruz, Mexico. A total of 384 O. sphacelatum plants were established on 24 Inga vera Willd. trees, with 16 plants per tree and 2 to 7 initial pseudobulbs. Individuals were monitored for nine months, and survival (%), root length (cm), number of shoots, and shoot length (cm) were recorded. Data were analyzed using descriptive statistics, nonparametric Kruskal-Wallis tests, the χ2 test for survival, and Pearson’s correlation analysis. Overall survival was high (91.15 %). Plants with a higher initial number of pseudobulbs showed significant increases in root development, shoot production, and shoot length (Kruskal-Wallis, p < 0.001), although differences in survival among pseudobulb groups were not significant (χ2 = 8.53, degrees of freedom = 4, p = 0.074). Root length was positively correlated with shoot length, highlighting the importance of early root development for successful establishment. The height at which plants were attached affected survival in the univariate analysis (3 m: 94.27 % vs. 5 m: 88.02 %; χ2 = 3.9, p = 0.048). The results demonstrate that the traditional shade-grown coffee system can be a viable habitat for the reintroduction of native epiphytic orchids. Initial vigor was associated with greater vegetative growth, whereas its association with survival was weak.