THE STRUCTURE AND COMPOSITION OF RIPARIAN VEGETATION IN TRINIDAD: A BASELINE FOR CONSERVATION AND RESTORATION By NATALIE BOODRAM A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2009 1 © 2009 Natalie Boodram 2 To my Mom 3 ACKNOWLEDGMENTS I would like to thank my chair Daniel Zarin, and committee members Tom Crisman, Mary Alkins-Koo, Carrie Reinhardt and Jane Southworth for all their guidance, advice and encouragement. This study was carried out with substantial support from institutions and agencies in Trinidad. The Department of Life Sciences of the University of the West Indies (UWI) provided laboratory space, field assistance, equipment and vehicles. The Curator and staff of the National Herbarium of Trinidad and Tobago (TRIN) assisted with plant identification and nomenclature. The Department of Surveying and Land Information provided spatial data. The UWI Analytical Services Unit provided laboratory space, equipment and reagents for soil particle size analysis. Soil samples were also analyzed at the Central Experiment Station (CES) of the Ministry of Agriculture, Land and Marine Resources (MALMR). CES also provided field vehicles and field support. In particular, I would like to thank the following CES staff members: Seunarine Persad, Imran Ali, Sean Joseph, Peter Abraham and Mahadeo Singh. The Forestry Division of MALMR also provided field support; in particular, Sheldon Williams helped establish my field sites in south Trinidad. I am also grateful to my family and friends who assisted in the field or helped review and edit my work. In particular, thanks go out to my mom and Tea. This study was financially supported by an Organization of American States Fulbright Ecology grant, a Compton Fellowship, and a University of Florida, Institute of Food and Agricultural Sciences research assistantship. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS ...............................................................................................................4 LIST OF TABLES...........................................................................................................................8 LIST OF FIGURES .......................................................................................................................10 ABSTRACT...................................................................................................................................11 CHAPTER 1 INTRODUCTION ..................................................................................................................13 2 RIPARIAN VEGETATION ALONG 12 RIVERS IN TRINIDAD ......................................18 Introduction.............................................................................................................................18 Methods ..................................................................................................................................20 Study Area.......................................................................................................................20 River Selection ................................................................................................................22 Site Selection...................................................................................................................24 Vegetation Data...............................................................................................................25 Environmental and Anthropogenic Data.........................................................................26 GIS and Map Data...........................................................................................................28 Laboratory Analyses........................................................................................................28 Data Analyses..................................................................................................................28 Results.....................................................................................................................................29 River Profiles...................................................................................................................30 Caura ........................................................................................................................30 Arouca ......................................................................................................................31 North Oropouche......................................................................................................33 Aripo.........................................................................................................................34 Caparo ......................................................................................................................36 Couva .......................................................................................................................38 L’ebranche................................................................................................................39 Cumuto .....................................................................................................................40 South Oropouche......................................................................................................43 Moruga .....................................................................................................................44 Poole.........................................................................................................................46 Summary of Environmental and Anthropogenic Characteristics of Riparian Zones......47 Summary of Plant Composition and Structure................................................................48 Importance value, species richness and diversity.....................................................48 Plant taxonomy.........................................................................................................49 Discussion...............................................................................................................................50 Anthropogenic Characteristics of Riparian Zones in Trinidad........................................50 Environmental Characteristics of Riparian zones in Trinidad ........................................53 5 Riparian Plant Composition and Vegetation Types in Trinidad .....................................54 Riparian Vegetation Structure .........................................................................................59 Riparian Zone Delineation ..............................................................................................60 Summary..........................................................................................................................61 3 RIPARIAN VEGETATION GROUPS AND DETERMINANTS IN TRINIDAD...............87 Introduction.............................................................................................................................87 Methods ..................................................................................................................................90 Data Collection and Scaling ............................................................................................90 Statistical Analyses..........................................................................................................91 Vegetation groups ....................................................................................................91 Indicator species analysis .........................................................................................92 Environmental and anthropogenic determinants of riparian vegetation ..................92 Results.....................................................................................................................................94 Discussion...............................................................................................................................99 Vegetation Groups...........................................................................................................99 Environmental and Anthropogenic Determinants of Riparian Vegetation ...................100 Variable Scales ..............................................................................................................103 Riparian Species in Trinidad .........................................................................................104 Conclusion.....................................................................................................................105 4 A RIPARIAN CONSERVATION AND RESTORATION INDEX FOR TRINIDAD ......132 Introduction...........................................................................................................................132 Human Impacts on Riparian Zones ...............................................................................132 Riparian Restoration......................................................................................................133 Riparian Indices.............................................................................................................134 Objectives......................................................................................................................136 Methods ................................................................................................................................137