The Impact of Hardwood Line-Planting on Tree and Amphibian Diversity in a Secondary Subtropical Wet Forest of Southeast Puerto Rico

Abstract The impact on tree and amphibian diversity of line-planting of tropical hardwoods—mahogany (Swietenia macrophylla × S. mahagoni) and mahoe (Hibiscus elatus)—was studied in a secondary subtropical wet forest of Puerto Rico. Common coqui (Eleutherodactylus coqui) and melodious coqui (E. wightmanae) are the most frequent frog species; forest coqui (E. portoricensis) is less abundant. Although relative abundance means were slightly greater in the undisturbed forest and during the wet season, differences were not statistically significant suggesting that line-planting did not significantly affect amphibian diversity. The line-planted areas had a slightly higher, but not statistically significant diversity, richness, and evenness of tree species than the unplanted forest. Multi-response permutation procedure (MRPP) showed statistically significant community composition differences between line-planting and control plot trees (T = −5.89, A = .86; p < .001). But mean similarity among plots in both the line-planted and control plots was relatively low at less than 50% of shared species, indicating high diversity of vegetation in the overall forest area. Canopy cover by tree species greater than 3 cm in dbh was much higher in the undisturbed forest but this difference may be reduced as the young line-planted hardwoods mature. Forest enrichment through line-planting of valuable timber species in secondary subtropical wet forest does not significantly affect tree diversity. KEYWORDS: amphibiancoquidiversityequitabilityforest enrichmentfroghardwood plantationHibiscus elatusline-plantingmahoemahoganyPuerto Ricosecondaryspecies richnesssubtropical wet forestsustainable forestrySwietenia spp The authors gratefully acknowledge the continuing support by Earthwatch Institute and the work of Earthwatch volunteer groups from 2000–2004 in the collection of the data on diversity and forestry development. In addition, the diversity evaluations were made possible by the fieldwork and identifications of species by Pedro Anglada and Nestor Molier. They also acknowledge the advice and methodological help given by Peter Weaver and John Perotta of the International Institute of Tropical Forestry; Jess Zimmerman, University of Puerto Rico; and Jill Thompson from the Luquillo Forest Dynamics Plot and the El Verde Field Station at El Yunque. The Las Casas de la Selva project gratefully acknowledges the continued support by the Institute of Ecotechnics (U.K. and USA) and the Global Ecotechnics Corporation of Santa Fe, New Mexico, USA. Notes Tropic Ventures Education and Research Foundation, Puerto Rico