Butterfly Community Temporal Trends and Responses to Resource Availability Along a Hydrologic Gradient of Montane Meadows Jennet C

Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2008 Butterfly community temporal trends and responses to resource availability along a hydrologic gradient of montane meadows Jennet C. Caruthers Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Ecology and Evolutionary Biology Commons Recommended Citation Caruthers, Jennet C., "Butterfly ommc unity temporal trends and responses to resource availability along a hydrologic gradient of montane meadows" (2008). Retrospective Theses and Dissertations. 15359. https://lib.dr.iastate.edu/rtd/15359 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Butterfly community temporal trends and responses to resource availability along a hydrologic gradient of montane meadows by Jennet C. Caruthers A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Ecology and Evolutionary Biology Program of Study Committee: Diane M. Debinski, Major Professor Brian J. Wilsey David L. Otis Iowa State University Ames, Iowa 2008 1453895 1453895 2008 ii DEDICATION To my husband, Hanh, for his patience and his loving support. iii TABLE OF CONTENTS CHAPTER ONE: GENERAL INTRODUCTION 1 Why Study Butterflies 1 Thesis Organization 2 References 4 Figures 6 CHAPTER TWO: BUTTERFLY INDICATORS OF MONTANE MEADOWS ALONG A HYDROLOGICAL GRADIENT: RESPONSES FROM A SPATIAL AND TEMPORAL SCALE 8 Abstract 8 Introduction 9 Methods 10 Results 13 Discussion 14 Conclusion and Acknowledgements 17 References 17 Figures and Tables 21 CHAPTER THREE: BUTTERFLY RESPONSES TO FLORAL AND HOST PLANT RESOURCES IN MONTANE MEADOWS 30 Abstract and Introduction 30 Methods 33 Results 36 Discussion 38 Conclusion and Acknowledgements 42 References 42 Figures and Tables 46 CHAPTER FOUR: GENERAL CONCLUSIONS 54 ACKNOWLEDGEMENTS 56 APPENDIX A: STUDY SITE LOCATION AND DESCRIPTIONS 57 APPENDIX B: LIST OF GALLATIN AND TETON MONTANE MEADOW 61 BUTTERFLY SPECIES APPENDIX C: R CODE 65 APPENDIX D: GYE BUTTERFLY HOST PLANT DATA 69 APPENDIX E: BUTTERFLY ABUNDANCE FOR GALLATIN AND 76 TETON REGIONS. 1 CHAPTER ONE: GENERAL INTRODUCTION Why study butterflies All over the world butterflies are studied to understand everything from the effects of agricultural loss from caterpillar pests to conservation of butterflies as indictors of biodiversity and climate change. Butterfly’s habitats range from urban area flower gardens to alpine mountain tops, and are one of the few “popular” insects to the general public. It is estimated that of the 13,750 species of true butterflies (Papilionoidea) in the world (Elhrich and Raven 1965; Robbins, 1982; Shields, 1989; and Robbins and Opler, 1997), 90% have been described taxonomically (Robbins and Opler, 1997). Butterflies are holometabolous insects, meaning they go through a complete metamorphosis. The existence of these different life stages means that butterflies fall into multiple functional groups, including herbivore and pollinator. Most North American butterflies have at least one generation a year, flying as the adult or imago during a specific time frame with one brood (univoltine) or multiple life cycles per year (multivoltine). The short life span for a generation and the short time span for active stages along with their relative ease of identification within the group of insects have made butterflies a taxonomic group of intense research. Butterfly physiology at any life stage, is intrinsically tied into microclimate as well as the plant community, making them susceptible to climate and anthropogenic changes. Their roles in nature have permitted a plethora of studies about butterflies and their relationships to terrestrial biodiversity and conservation. The Greater Yellowstone Ecosystem (GYE) includes Yellowstone National Park, Grand Teton National park, and portions of surrounding national forests and private lands (Patten, 1991; and Romme and Turner, 1991), the headwaters to three major continental- scale watersheds (Marston and Anderson, 1991), as includes three states (Idaho, Montana, and Wyoming). Elevated levels of CO2 are expected to increase temperatures within the GYE, however there is uncertainty as to how climate change will alter precipitation across the region (Cushman et al., 1988; Romme and Turner, 1991). An estimated 184 butterfly species occur in Montana and 197 in Wyoming (Robbins and Opler, 1997). Utilizing weather station data from the northern and southern regions of the GYE we can see that over the past twenty years weather patterns for precipitation (Figure 1) and temperature (Figure 2) 2 are regionally different and variable. How these regional differences will affect the GYE butterfly community is uncertain. However a good understanding of these communities will help to establish a basis for future studies investigating climate change. Butterflies are closely associated with the plant community. Most adult butterflies require nectar resources from flowering forbs. The synchrony between flower and adult butterflies phenology can be very narrow (Calabrese et al., in press) and may become a problem with increased rates of climate change as date of first emergence becomes early over time (Inouye et al., 2000). Phytophagous insects, like butterflies, are thought to have coevolved with their larval host plants (Wahlberg, 2001) and are tied to specific species or groups of host plants. Many butterfly species are very nectar and host plant specific, while others are considered nectar opportunistic and can utilize a range of closely related plant species for host plants (Scott, 1986; Grundel et al., 2000; Baz, 2002; Dennis et al., 2004; and Hardy et al., 2007). Whether the butterflies are generalists or specialists, plants are an important resource defining aspects of habitat quality and influence the distribution of butterflies across the landscape (Tudar et al., 2004; and Dennis et al., 2006; Menendez et al., 2007). My research examined the temporal patterns of montane meadow butterfly communities within two regions of the GYE in relation to meadow moisture availability and quantity of floral and larval host plant resources. Ninety species of butterflies have been observed during this work within the GYE montane meadow system since 1997. This research contributes to the knowledge of butterfly community patterns and resource requirements. This work identifies species of conservation concern relative to potential future landscape changes and provides a long-term perspective on butterfly community associations in a relatively pristine system with minimal anthropogenic disturbance (Patten, 1991). Thesis Organization This thesis presents results from a ten-year study within the GYE assembled into four chapters. This chapter presents a general introduction of the different aspects of my thesis research as well as goals and importance of this work. Chapter Two describes the butterfly associations with meadow type based on a naturally occurring moisture gradient. I also 3 identify specific species of butterflies that are indicators for different meadow habitats that can be used to monitor meadow quality or as an umbrella species for conservation purposes. Chapter Three evaluates the relationship between flowering plant richness and abundance as a driver for butterfly abundance in meadow patches. Chapter Four is a summary of conclusions for my thesis research. There are four appendixes included at the end of the thesis. The first appendix, Appendix A, contains a table of all the study sites and their locations given in UTM (Universal Transverse Mercator) coordinates with descriptive directions for finding each site. It also contains maps for each study region with the location of each site. Appendix B contains a list of butterfly species surveyed since 1997 by region and each species total abundance averaged over all surveyes for each region. Appendix C contains code written in R for Chapter Two and Chapter Three statistical analyses. Appendix D contains butterfly larval host plant information, including a list of host plants for each butterfly identified and a figure graphing raw data for host plant percent cover. Appendix E includes a table for each region presenting raw data on butterfly abundance averaged by meadow type for each year the region was surveyed. Jennet C. Caruthers is a graduate student in the interdepartmental program, Ecology and Evolutionary Biology and conducted two years of data collection, as well as data analysis and written preparation of this manuscript. Dr. Diane Debinski, along with a number of other collaborators, organized this project in 1997 and has been involved in data collection each year except for 2001. Dr. Debinski kept funding for this research available for its continuation and provided invaluable guidance and editorial advice over the course of this project. Support for the statistical program R: a language and environment for statistical computing (R Development Core Team, 2007) was provided by Hadley Wickham, Diane Cook, and Phillip Dixon. 4 References Baz, A., 2002. Nectar plant sources for the threatened Apollo butterfly (Parnassius Apollo L. 1758) in populations of central

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