Characterizing the Stream Environments Associated with Introduced Species Across Spatial Scales in Hawai‘I
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CHARACTERIZING THE STREAM ENVIRONMENTS ASSOCIATED WITH INTRODUCED SPECIES ACROSS SPATIAL SCALES IN HAWAI‘I A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI‘I AT MĀNOA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN NATURAL RESOURCES AND ENVIRONMENTAL MANAGEMENT DECEMBER 2018 By Brendan T. Martin Thesis Committee: Yin-Phan Tsang, Chairperson Melissa Price Tim Grabowski Keywords: Hawai‘i, stream, freshwater, tropical, introduced, alien, modeling, landscape Copyright by Brendan T. Martin 2018 ii Acknowledgements I would like to extend my gratitude to my committee chair, Yin-Phan Tsang, for her guidance and friendship throughout my research. I would also like to thank my committee members, Tim Grabowski and Melissa Price, for their support and invaluable comments and suggestions that enabled me to complete this thesis. I thank my lab family, Hannah Clilverd, Yu-Fen Huang, and Kelly-rose Lariosa for their critiques and support during the many phases of my research. I am extremely grateful to Glenn Higashi of Hawaii’s Division of Aquatic Resources who provided the biological survey data which made my research possible. Additionally, I would like to thank Ralph Tingley, Dana Infante, and Kyle Herreman for assisting with acquisition and assessment of landscape data sources. I would like to thank many colleagues that contributed their expert knowledge on Hawaiian streams to the development of research including Cory Yap, Ayron Strauch, Malie Beach- Smith, Abigail Lynch, Dan Polhemus, Kauaoa Fraiola, and Gordon Smith. Finally, I am thankful for my family who has always supported my endeavors, and my wife for being my biggest supporter along the way. iii Abstract Introduced freshwater species are among the most significant threats to native biodiversity worldwide. In Hawai‘i, introduced stream species impact native populations through predation, competition, habitat alterations, and exposure to parasites and diseases. This study utilized biological and in-stream environmental survey data collected by state researchers and landscape variables from the 2015 National Fish Habitat Partnership assessment to assess habitat use and distribution of introduced stream species throughout Hawai‘i. Surveyed in-stream environmental attributes (e.g., temperature, substrate, dissolved oxygen) were examined to determine the use of in-stream attributes of introduced species. Associations between landscape metrics and species were investigated using both natural and anthropogenic variables, assessed at multiple spatial catchments. Prominent associations with in-stream attributes included water temperature, depth, and substrate type. Species-landscape metric associations indicated that natural variables including downstream slope, elevation, and upstream rainfall, as well as anthropogenic variables including local and upstream population were important landscape predictors of species presence. Stream reach suitability of species was modeled for selected introduced stream species based on their observed occurrences throughout Hawai‘i using important landscape scale factors. Areas with the greatest suitability among taxa included the low-sloped and low-elevation areas of O‘ahu, windward Kaua‘i, and central Maui, as well as select streams on Moloka‘i and Hawai‘i Island. Information on species environmental associations at different spatial scales will improve understanding of biological invasions in tropical island ecosystems. This served to inform future management strategies on prioritization of streams for conservation and introduced species removal. iv Table of Contents List of tables ................................................................................................................................................ viii List of figures ................................................................................................................................................. x List of acronyms ............................................................................................................................................xi Chapter One - Introduction .......................................................................................................................... 1 1.1 Background ......................................................................................................................................... 1 1.1.1 Introduction ............................................................................................................................ 1 1.1.2 Stream ecosystems in Hawai‘i ............................................................................................... 1 1.1.3 Stream alterations in Hawai‘i ................................................................................................. 2 1.1.4 Introduced stream species is Hawai‘i .................................................................................... 3 1.1.5 Landscape perspective of stream ecosystems........................................................................ 5 1.2 Objectives ............................................................................................................................................ 6 1.3 Study area ........................................................................................................................................... 6 1.4 Study data ........................................................................................................................................... 7 Chapter One Appendices .......................................................................................................................... 9 Appendix: Tables .............................................................................................................................. 9 Appendix: Figures .......................................................................................................................... 23 Chapter Two - Characterizing introduced species associations with in-stream environmental attributes .................................................................................................................................................................... 31 2.1 Introduction ...................................................................................................................................... 31 2.2 Methods ............................................................................................................................................ 32 2.2.1 Study design .......................................................................................................................... 32 2.2.2 In-stream environmental attribute selection ...................................................................... 32 2.2.3 Taxa selection ....................................................................................................................... 32 2.2.4 Multivariate analysis ............................................................................................................. 33 2.2.5 Zero-inflated models ............................................................................................................. 34 2.3 Results ............................................................................................................................................... 35 2.3.1 Principal component analyses .............................................................................................. 35 2.3.2 Canonical correspondence analyses .................................................................................... 35 2.3.3 Zero-inflated models ............................................................................................................. 36 2.4 Discussion .......................................................................................................................................... 37 2.5 Conclusion ......................................................................................................................................... 39 v Chapter Two Appendices ........................................................................................................................ 40 Tables ............................................................................................................................................. 40 Figures ............................................................................................................................................ 49 Chapter Three - Characterizing introduced species associations with landscape-scale environmental factors ......................................................................................................................................................... 53 3.1 Introduction ...................................................................................................................................... 53 3.2 Methods ............................................................................................................................................ 54 3.2.1 Attributing biological datasets with the spatial framework ................................................ 54 3.2.2 Biological data preparation .................................................................................................. 54 3.2.3 Assembly of landscape-scale environmental data, and link with spatial framework ........... 55 3.2.4 Assessment of waterfalls as barriers