UN1VER:::ITY OF HAWAI'I LIBRARY HABITAT USE BY THE ENDANGERED HAWAIIAN HONEYCREEPER (PSEUDONESTORXAN11l0PRYS) EFFECTS OF PHYSIOGNOMY AND FLORISTICS A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI'I IN PARTIAL FULFILLMENT FOR THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN BOTANY DECEMBER 2007 By Valerie K. Stein Thesis Committee: David Duffy, Chairperson Kent Bridges Sheila Conant We certify that we have read this thesis and that, in our opinion, it is satisfactory in scope and quality as a thesis for the degree of Master of Science in Botany. THESIS COMMITIEE ii Copyright © by Valerie Stein 2007 iii DEDICATION This research is dedicated to all those past and present working to protect and restore the amazing flora and fauna that are Haleakala. iv ACKNOWLEDGMENTS This research owes itself in part, to collaboration with many individuals. Conversations on Maui Parrotbill recovery with Scott Fretz first sparked this particular study and inspired me to pursue funding. The fieldwork component of this project would not have been possible without the tremendous effort put forth by my two field technicians: Laura Arnold and Emily Severson. Laura and Emily assisted me throughout the course of two field seasons, providing humor and encouragement as well as research assistance in conditions that might have deterred the heartiest of souls. The Resources Management Division at Haleakalii National Park was my 'ohana and home away from home when I had none, providing camaraderie as well as much needed logistical support throughout the course of a difficult and challenging field project. Mahalo nui loa Steve Anderson, Cathleen Bailey, Timmy Bailey, Sean Birney, Chuck Chimera, lain Emmons, Ross Hart, Bill Haus, Raina Kaholoa'a, Terry Lind, Ron Nagata, Gale Plana, Regan Ritchie, Ted Rodrigues, Aloha Smith, Joy Tamayose and Patti Welton for making my time on "the mountain" so memorable. Cathleen Bailey in particular served as a mentor and I am grateful for the latitude she provided me in designing and running my own research project. I thank Windward Aviation and the exceptional helicopter pilots of Jim Hobbs, Eric Pacheco, Pete Voorhees, and Don Shearer for transporting us and our gear safely to and from the field. I thank my committee members: Dr. David Duffy, Dr. Sheila Conant and Dr. Kim Bridges for their encouragement and interest in applied ecological studies. David and Sheila's enthusiasm for my research kept me motivated during moments of self doubt, v and Kim enthusiastically stepped in as a late addition on my project. Dr. Joe Fragoso provided helpful comments on study design at earlier stages of my project and Dr. Andy Taylor provided insightful comments on analyses at different stages of my work. I thank my officemates: Stephanie Joe, Christina McGuire, Elizabeth Keenan, Dana Crompton, and Lindsay Young for their support and good humor over the years. I also thank Meghan Dailer, Sheldon Plentovich, Stacy Enoch, and Arlene Sison for their support and friendship during much of my graduate school experience. I thank my parents for encouraging me to be and do whatever I wanted and for exposing me to the wonders of the natural world as a child. The experiences I had growing up on their dairy farm in rural upstate NY set the course for my future at a young age and I am forever grateful for that time. Finally, it is with much gratitude that I thank Jeff Foster for his patience, support, and encouragement. My Master's research was funded by the National Park Service and carried out under a cooperative agreement with the Pacific Cooperative Studies Unit of the University of Hawai 'i. vi ABSTRACT Understanding how habitat affects endangered species can provide critical information to scientists and managers faced with restoring habitat. The Maui Parrotbill, one of the most endangered honeycreepers in Hawai'i, is currently restricted to the bigh elevation rainforests of East Maui. I conducted research on habitat use by this species in Manawainui, an area of montane rainforest under consideration for release of captive­ reared parrotbill in Haleakalii National Park on Maui. I sought to empirically determine how forest stand structure and composition might influence parrotbill distribution in Manawainui and how these factors might influence the suitability of this area as a potential release site for captive-reared birds. My main objectives were to quantify the effects offorest stand structure and plant composition on parrotbill habitat selection at the macrohabitat (home range) and microhabitat (foraging site) scales. I studied habitat suitability for Maui Parrotbill at 21 10-hectare sites (10 used, 11 unused) in mixed Metrosideros polymorpha-Acacia koa forest in Manawainui from February-August 2005 and January-August 2006. A combination of bird and vegetation surveys was utilized to compare vegetation parameters between used and unused areas at different spatial scales of macrohabitat and microhabitat. Parrotbill exhibited non-random habitat use at multiple spatial scales. At the macrohabitat scale, vegetation structure and composition differed significantly between used and unused areas. Parrotbill were associated with areas typified by large diameter trees and bigher densities of understory, subcanopy and canopy vegetation layers. Significant indicator plants of parrotbill habitat use at the macrohabitat scale were Cheirodendron trigynum, Jlex; anomala, and Me/icope spp. At the microhabitat vii scale, parrotbill selected fomging sites non-randomly and were most influenced by ovemll species composition. Birds selectively fomged on C. trigynum, Me/icope spp., Acacia koa, Coprosma spp., and Rubus hawaiensis in disproportion to availability. Ovem1l vegetation structure did not differ significantly between used and unused fomging plots, however parrotbill did selectively fomge on smaller diameter trees and used the subcanopy and canopy more than expected. These data highlight the importance of diverse, well developed forest for this species and have important management and conservation implications. viii TABLE OF CONTENTS ACKOWLEDGMENTS .............................................................................v ABSTRACT ........................................................................................•vii LIST OF TABLES ...................................................................................xi LIST OF FIGURES .................................................................................xii CHAPTER 1. INTRODUCTION ...................................................................................... 1 BACKGROUND .................................................................................................................. 1 STUDY SPECIES ................................................................................................................ 3 RESEARCH OBJECTNES .................................................................................................... 6 CHAPTER 2. HABITAT USE BY MAUl PARROTBILL: A MULTISCALE APPROACH ..................................................................................................................... 11 INTRODUCTION ........................................................................................................ 11 METHODS ................................................................................................................... 14 STUDY SITE •••..•....••....••.....••••••••••••••••••••••••.•••..........••••...••••••••••••••••••••.••.•.......•.....•..... 14 BIRD SURVEyS •...................•...•••...•••••...•.•..•••..•................•...•••••...•.•...•.•...•..•.............. 16 VEGETATION SAMPLING (MACROHABITAT) •.••.•.••...•.•••.••••••..••..............•.....••..•.••••••••.• 17 DATAANALYSES-MAcROHABITAT ..............••.•.••.•.•..••..•..••......•............•.•...•.•...•.•....•. 18 VEGETATION SAMPLING (MICROHABIT AT) ................................................................. 22 DATA ANALYSES-MICROHABITAT •••.•.••.•..••...•.......•.....•...•..•••••••••••••••••..••..•..•............ 23 RESULTS ..................................................................................................................... 24 ix BIRD SURVEYS ........................................................................................................... 24 MACROHABITAT •...••....•...................................•.••....•.•...•.•...•.••..•.....•.•....•••...••.••..••.•.. 25 MICROHABITAT .......................................................................................................... 27 DISCUSSION ............................................................................................................... 28 MACROHABITAT ........................................................................................................ 28 MICROHABITAT •..••.•..••..............•........•........•.••..•.•.••..•.•.•.•.............................•............ 30 CHAPTER 3. MAll PARROTBILL FORAGING HABITAT •....••.............................. .46 INTRODUCTION ........................................................................................................ 46 METHODS .•......•.•..••.•...•..••..••••..•.•..•.•..........••••.....•....•.••..••.•..•........•..•..•.....•••...•.•...••... 47 BIRD SURVEYS .......••..........................................••...................................................... 49 FORAGING OBSERVATIONS ........................................................................................ 50 VEGETATION SURVEYS