University of Connecticut OpenCommons@UConn Master's Theses University of Connecticut Graduate School 12-27-2012 Forest Regeneration on the Osa Peninsula, Costa Rica Manette E. Sandor University of Connecticut, [email protected] Recommended Citation Sandor, Manette E., "Forest Regeneration on the Osa Peninsula, Costa Rica" (2012). Master's Theses. 369. https://opencommons.uconn.edu/gs_theses/369 This work is brought to you for free and open access by the University of Connecticut Graduate School at OpenCommons@UConn. It has been accepted for inclusion in Master's Theses by an authorized administrator of OpenCommons@UConn. For more information, please contact [email protected]. Forest Regeneration on the Osa Peninsula, Costa Rica Manette Eleasa Sandor A.B., Vassar College, 2004 A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science At the University of Connecticut 2012 i APPROVAL PAGE Masters of Science Thesis Forest Regeneration on the Osa Peninsula, Costa Rica Presented by Manette Eleasa Sandor, A.B. Major Advisor________________________________________________________________ Robin L. Chazdon Associate Advisor_____________________________________________________________ Robert K. Colwell Associate Advisor_____________________________________________________________ Michael R. Willig University of Connecticut 2012 ii Acknowledgements Funding for this project was provided through the Connecticut State Museum of Natural History Student Research Award and the Blue Moon Fund. Both Osa Conservation and Lapa Ríos Ecolodge and Wildlife Resort kindly provided the land on which various aspects of the project took place. Three herbaria helpfully provided access to their specimens: Instituto Nacional de Biodiversidad (INBio) in Costa Rica, George Safford Torrey Herbarium at the University of Connecticut, and the Harvard University Herbaria. I cannot thank the staff of these herbaria enough for all of their assistance. Thanks are also due to FUNDATEC and Instituto Tecnologico de Costa Rica. Thanks are due to a great number of people for their assistance and contributions to this project. Marvin Lopes-Morales assisted with data collection in the field as well as provided his incredible knowledge of the flora (and fauna) of the Osa Peninsula. Julian Reese was also instrumental in data and sample collection in the field. Data on functional traits were collected with assistance from A. Wendt and A. DeFancesco. M. Ortega Guitierrez, M. Arguedas, M. Morales Salazar, L. Acosta, M. Diaz, and E. Diaz all also helped with the collection of the data in the field. The administrative assistance of A. St. Onge, P. Anderson, K. Tebo, G. Saborio, and C. Monge, either in Connecticut or Costa Rica, was invaluable. I owe much gratitude to Robin Chazdon who set up the successional chronosequence and allowed me to enhance and analyze the data collected therein. She also contributed a great deal to the framework and the written product of the project. My committee members, Michael Willig and Robert Colwell, also contributed a great deal of their time and expertise to support me in the completion of this project. iii A few other people provided advice and expertise. Reinaldo Aguilar was essential for the identification of many species of trees. Braulio Vilchez Alvarado loaned his time to introduce me to the Osa Peninsula. Rebecca Cole, Alan Townsend, Cory Cleveland, Edgar Oritz Malavassi, and Juan Pablo Arroyo Moya all provided assistance on leaf collection, soil analysis, and/or GIS analysis. A number of graduate students in the Chazdon-Silander lab complex and out were of great assistance. Finally, I would like to thank my friends and especially my family who supported me throughout this process. iv Contents Acknowledgements ...................................................................................................................................... iii Thesis Abstract ............................................................................................................................................. vi CHAPTER 1: ................................................................................................................................................... 1 Introduction .............................................................................................................................................. 2 Methods .................................................................................................................................................... 4 Results ..................................................................................................................................................... 11 Discussion................................................................................................................................................ 15 Tables ...................................................................................................................................................... 22 Figures ..................................................................................................................................................... 24 References .............................................................................................................................................. 32 Appendix ................................................................................................................................................. 37 CHAPTER 2: ................................................................................................................................................. 50 Introduction ............................................................................................................................................ 51 Methods .................................................................................................................................................. 52 Results ..................................................................................................................................................... 61 Discussion................................................................................................................................................ 67 Tables ...................................................................................................................................................... 73 Figures ..................................................................................................................................................... 81 References .............................................................................................................................................. 87 Appendix ................................................................................................................................................. 91 v Thesis Abstract Woody species diversity of secondary forest has the potential to converge with that found in old growth forest. This study is the first to examine multiple aspects of species and reproductive trait diversity, and their relationship to each other, across a successional chronosequence encompassing recently abandoned pasture, older second growth, and old growth forest. We focused on dispersal mechanism, pollinator, diaspore length, and fruit length as key reproductive traits. Species richness and species diversity increases with increasing age of forest. Diaspore size and diversity as well as fruit size generally increased with increasing age of forest, but fruit size diversity did not significantly change with increasing age of forest. Abundance of animal-dispersed species increased whereas wind-dispersed species decreased in abundance over succession. Insect-pollinated individuals were most abundant, especially in early and mid-second growth forests, whereas wind-pollinated individuals were more abundant in late second-growth forests and even more abundant in old growth forests. Diaspore diversity, pollination diversity, and reproductive trait richness were significantly correlated with species richness, but other measures of reproductive trait diversity were not. Our results suggest that different community assembly processes involve different reproductive traits, and that secondary forest plots are on a trajectory to recover levels of diversity found in old growth forest. Recovery of anthropogenically disturbed forest can also be affected by remnant trees, left when tropical forests are cleared for agriculture or grazing. These old growth trees act as nuclei of forest regeneration following field abandonment. This study is among the first to investigate the effects of remnant trees on nearby forest structure and biodiversity, 20-30 years post- abandonment. Regeneration of woody species ≥ 1 cm or 5 cm diameter at breast height (dbh) beneath remnant trees does not significantly differ in density or basal area. Species richness is vi higher around remnant trees than around reference trees. The species composition around remnant trees is significantly different from that around reference trees and more closely resembles that of nearby old growth forest. A multinomial classification method to categorize species as old growth specialists, second growth specialists, or generalists used in the chronosequence plots was applied to the species found around remnant and reference trees. The proportion of old growth specialists and generalists around remnant trees is