UNLV Theses, Dissertations, Professional Papers, and Capstones 12-1-2020 Effects of Wildfire on Plant and Insect Pollinator Communities in the Mojave Desert Nha Trang Vivian Sam Follow this and additional works at: https://digitalscholarship.unlv.edu/thesesdissertations Part of the Environmental Sciences Commons, and the Terrestrial and Aquatic Ecology Commons Repository Citation Sam, Nha Trang Vivian, "Effects of Wildfire on Plant and Insect Pollinator Communities in the Mojave Desert" (2020). UNLV Theses, Dissertations, Professional Papers, and Capstones. 4079. https://digitalscholarship.unlv.edu/thesesdissertations/4079 This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in UNLV Theses, Dissertations, Professional Papers, and Capstones by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. EFFECTS OF WILDFIRE ON PLANT AND INSECT POLLINATOR COMMUNITIES IN THE MOJAVE DESERT By Nha Trang Vivian Sam Bachelor of Science – Biological Sciences University of Nevada, Las Vegas 2017 A thesis submitted in partial fulfillment of the requirement for the Master of Science – Biological Sciences School of Life Sciences College of Sciences The Graduate College University of Nevada, Las Vegas December 2020 Copyright 2021 by N.T. Vivian Sam All Rights Reserved Thesis Approval The Graduate College The University of Nevada, Las Vegas November 12, 2020 This thesis prepared by Nha Trang Vivian Sam entitled Effects of Wildfire on Plant and Insect Pollinator Communities in the Mojave Desert is approved in partial fulfillment of the requirements for the degree of Master of Science – Biological Sciences School of Life Sciences Scott Abella, Ph.D. Kathryn Hausbeck Korgan, Ph.D. Examination Committee Chair Graduate College Dean Stanley Smith, Ph.D. Examination Committee Member Daniel Thompson, Ph.D. Examination Committee Member Michael Webber, Ph.D. Examination Committee Member Helen Neill, Ph.D. Graduate College Faculty Representative ii ABSTRACT Effects of wildfire on plant and insect pollinator communities in the Mojave Desert By N.T. Vivian Sam Dr. Scott R. Abella, Examination Committee Chair Associate Professor University of Nevada, Las Vegas The changing fire regime of landscapes across the Mojave Desert has prompted considerable research on its effects on plant community recovery, but it has not been widely studied what effects wildfire may have on native pollinators and the vital ecosystem services they provide. Ecological changes from increased wildfire severity from invasive exotic annual grasses will likely continue influencing pollinator habitats and floral resources. Understanding the effects that wildfires have on pollinators is valuable to make decisions as to whether active management and restoration activities are required to conserve ecologically vital pollinator functions. The intention of this thesis was to examine the effects of wildfire on insect pollinator communities and whether insect pollinator communities may be associated with different vegetative community structures in burned and unburned areas. This thesis assessed plant and pollinator community differences between burned and unburned areas on three fires that occurred in 2005 in and around Red Rock National Conservation Area in Clark County, Nevada of the eastern Mojave Desert. The study was conducted through pan trapping, aerial netting, and floral visitor observations that took place in 2019-2020 and yielded over 4,600 individual insect pollinators within 62 taxa. Effects such as burn status and iii various plant community characteristics on pollinator abundance and richness after 14-15 years was evaluated. No significant differences occurred between burn status on general plant community variables including plant cover and richness. Burn status did not have a significant effect on overall richness and abundance of the pollinator communities of interest. However, burn status differences within the orders of Coleoptera, Hymenoptera, and Lepidoptera appear to be contingent on both sampling season and year. Burned sites had higher pollinator density in fall 2019, though this pattern did not occur in either of the spring seasons. Spring 2019 burned areas showed higher Hymenoptera density, while spring 2020 burned areas showed higher Lepidoptera density. Mixed- model analyses of variance show associations of fire sites and various pollinator taxa and plant species. Considering that results of this study are varied, a main conclusion is that pollinators are resilient to wildfire and have appeared to recover to unburned pollinator community levels more fully than vegetation at 14 and 15 years since disturbance. Although these results do support hypotheses in the literature that predict insect pollinator groups to be marginally affected by wildfire, interpretations cannot be made on specific individual pollinator species or on how pollinators may respond immediately after wildfire occurs. Information from this research provides a basis for future studies on Mojave Desert wildfire and pollinator communities. These findings add to the broader understanding of Mojave Desert wildfire effects on pollinators and can help inform the management and restoration of pollinators and their habitats in arid lands. iv ACKNOWLEDGEMENTS I would not be the student I am today without the mentorship, teachings, and motivation of my thesis advisor and committee chair, Dr. Scott Abella, for whom I have so much gratitude. I am humbled to have been given the opportunity to join his laboratory as an undergraduate, where I began my journey as an ecology student. Dr. Scott Abella has, above and beyond, supported me every step of the way. I would also like to extend my sincere gratitude to Lindsay Chiquoine, who provided so much of her time and insight to guide me within my thesis and as a student and ecologist. Lindsay’s influential and contagious passion for ecology and science is why I look up to her. Many volunteers have assisted to make the field and laboratory work of my thesis possible: Elizabeth Gutierrez, Raul Gesmundo, Carmen Lee, Shelley Porter, Sarah Erskine, Francisco Valenzuela, and most especially, my partner Randy Bae. Thank you all. Past students of the Abella Applied Ecology Lab have provided friendship, encouragement, and have inspired me through leading by extraordinary example: Audrey Rader, Ka-Voka Jackson, Tiffany Pereira, Mary Balogh, Dominic Gentilcore, and Camille Traylor. My Graduate Advisory Committee members Dr. Stanley Smith, Dr. Daniel Thompson, Dr. Michael Webber, and Dr. Helen Neill have all played a significant role in my thesis. I am appreciative that they have shared their time and knowledge with me. The opportunity of a Graduate Assistantship with the UNLV Academic Success Center has allowed me to achieve my master’s degree. Through this position, I was able to develop myself professionally, and was always cheered on by smiling faces and words of encouragement by fellow graduate assistants, faculty, and staff. v TABLE OF CONTENTS Abstract ........................................................................................................................................ iii Acknowledgements ....................................................................................................................... v Table of Contents ........................................................................................................................ vi List of Tables ............................................................................................................................. viii List of Figures .............................................................................................................................. ix Chapter 1: Introduction ............................................................................................................... 1 References ................................................................................................................................... 4 Chapter 2: Literature Review ...................................................................................................... 6 Introduction ...................................................................................................................................6 Pollinator importance .................................................................................................................. 7 Fire in the Mojave Desert ............................................................................................................ 9 General plant-pollinator relations at a community scale ........................................................... 11 Effects of fire on insect pollinators ........................................................................................... 13 Invertebrate studies and limitations ........................................................................................... 14 References ................................................................................................................................