Annual Variation in Bee Community Structure in the Context of Disturbance (Niagara Region, South-Western Ontario) ~" . by Rodrigo Leon Cordero, B.Sc. A thesis submitted to the Department of Biological Sciences in partial fulfilment of the requirements for the degree of Master of Science September, 2011 Department of Biological Sciences Brock University St. Catharines, Ontario © Rodrigo Leon Cordero, 2011 1 ABSTRACT This study examined annual variation in phenology, abundance and diversity of a bee community during 2003, 2004, 2006, and 2008 in rec~6vered landscapes at the southern end of St. Catharines, Ontario, Canada. Overall, 8139 individuals were collected from 26 genera and sub-genera and at least 57 species. These individuals belonged to the 5 families found in eastern North America (Andrenidae, Apidae, Colletidae, Halictidae and Megachilidae). The bee community was characterized by three distinct periods of flight activity over the four years studied (early spring, late spring/early summer, and late summer). The number of bees collected in spring was significantly higher than those collected in summer. In 2003 and 2006 abundance was higher, seasons started earlier and lasted longer than in 2004 and 2008, as a result of annual rainfall fluctuations. Differences in abundance for low and high disturbance sites decreased with years. Annual trends of generic richness resembled those detected for species. Likewise, similarity in genus and species composition decreased with time. Abundant and common taxa (13 genera and 18 species) were more persistent than rarer taxa being largely responsible for the annual fluctuations of the overall community. Numerous species were sporadic or newly introduced. The invasive species Anthidium oblongatum was first recorded in Niagara in 2006 and 2008. Previously detected seasonal variation patterns were confirmed. Furthermore, this study contributed to improve our knowledge of temporal dynamics of bee communities. Understanding temporal variation in bee communities is relevant to assessing impacts caused on their habitats by diverse disturbances. 2 ACKNOWLEDGEMENTS I would like to sincerely thank all the people who have fought for the right of education and have made moments like this to happen. Futthermore, I would like to thank my parents, grandparents and their preceding generations who have made their best for providing this basic right to everyone. Nevertheless, this task is still far from being finished. I promise to push in order to make that day to come. I would also like to thank Pegah, mi queridafamilia, khounevadeh y amigos, for all the life experiences we are sharing in addition to the wonderful support and the grateful and altruistic collaboration that I have had in these two years. Moreover, I would also like to give recognition to teachers and professors such as Srta. Benita, Salvador, Jesus, Chano, Ma Jesus, Fontan, Esperanza, Fernando, Marga and Pilar Julia for their lives devoted to education and research. In addition, I would also like to deeply thank Marfa Teresa Torrents y su equipo de Beques La Caixa, for the teamwork they carry out. Furthermore, I would like to extend my thanks to all of my professors at this university. I would begin with my supervisor, Professor Miriam Richards, and the members of my committee Professors Daniel McCarthy and Joffre Mercier. In addition, I would also like to include Professors Fiona Hunter, Glen Tattersall and Tony Shaw. I would like to acknowledge all for their contribution to the research and for the professional and personal training that as a graduate student I may have been able to obtain. Finally, I would like to thank my fellow students and lab mates, for all the moments shared. In this regard, I would like to extend my special gratitude to Rola for all her deeply sincere attention. To all the above, I am indebted. 3 A mis abuelas, y a todas aquellas personas que no pudieron estudiar en su infancia , And'to the effort of the peoples of the two continents where I have studied "Culture, which makes talent shine, is not completely ours either, nor can we place it solely at our disposal. Rather, it belongs mainly to our country, which gave it to us, and to humanity, from which we receive it as a birthright" Jose Martf "La cl;lltura, por 10 que el talento brilla, tampoco es nuestra por entero, ni podemos disponer de ella para nuestro bien, sino es principalmente de nuestra patria, que nos la di6, y de la humanidad, a quien heredamos" Jose Martf 4 TABLE OF CONTENTS PAGE ABSTRACT ,£,,' 2 ACKNOWLEDGMENTS 3 TABLE OF CONTENTS 5 LIST OF TABLES 7 LIST OF FIGURES 9 CHAPTER I: ANNUAL VARIATION IN BEE COMMUNITY STRUCTURE 1. INTRODUCTION AND LITERATURE REVIEW 11 1.1. The Carolinian Zone and the Niagara Region 11 1.2. The importance of bee communities 12 1.3. Temporal variation in animal communities 12 1.4. The temporal variation in bee communities 14 1.4.1. Annual variation in the bee community of Caledon Hills 15 1.4.2. Annual variation in desert bee communities 19 1.4.3. Annual family-level variation in an Appalachian bee community 21 1.4.4. Annual variation in a rainforest bee community 21 1.4.5. Bee community variation among decades 22 1.4.5.1. Decadal variation of desert bee communities 22 1.4.5.2. Decadal variation in a Michigan bee community 23 1.4.5.3. The Carlinville bee community from the 1880s to 1970s 24 1.4.5.4. The study of the bee community of Plummers Island from 1909 to 2006 25 1.4.5.5. Historical and re-sampling surveys of a Colorado bee community 26 1.4.5.6. Analysis of historical studies on long-term bee community variation 26 1.5. A bee community of the Niagara Region 28 1.6. Thesis objectives and hypotheses 31 2. METHODS 34 2.1. Study sites 34 2.2. Collection period of specimens 36 2.3. Bee collections 37 2.4. Bee handling 'arid identification 39 • 2.5. Ecological traits of the bee community 40 2.6. The phenology of the bee community 41 2.7. Abundance of the bee community 41 2.8. Annual variation in abundance 42 2.9. The diversity of the bee community 42 2.10. Annual variation in diversity 42 5 TABLE OF CONTENTS (Continued) PAGE 2. METHODS (Continued) 2.11. Statistical analysis 44 2.11 .1. Tests for normality 44 2.11.2. Data analysis of the phenology 44 2.11.3. Data analysis of abundance among sites 45 2.11.4. Data analysis of annual variation in abundance 45 2.11.5. Data analysis of diversity 46 2.11.6. Tests for estimated diversity variation among years 46 2.11.7. Tests for annual differences in the number of genera and species richness 46 2.11.8. Tests for the annual turnover of genera and species 47 2.11.9. Additional data analysis of the annual variation in diversity 48 3. RESULTS 49 3.1. General description of the bee community 49 3.2. The phenology of the bee community 49 3.3. Abundance of the bee community 55 3.4. Annual variation in abundance 66 3.5. The diversity of the bee community 74 3.6. Annual variation in diversity 81 4. DISCUSSION 97 4.1. General aspects of the bee community 97 4.2. Phenology of the bee community 98 4.3. Abundance of the bee community 100 4.4. Annual variation in abundance 101 4.5. The diversity of the bee community 104 4.6. Annual variation in diversity 104 4.7. Conclusion 115 5. REFERENCES 119 6. APPENDIX I 129 • 7. APPENDIX II 137 6 LIST OF TABLES Table Title Page Table 1 Diagram of the transect patterns used in-tItis study over the 38 flight seasons of 2003,2004,2006 and 2008 Table 2 List of the number of bees collected per species, using pan 50 traps, in 2003, 2004, 2006 and 2008. Table 3 Inter-annual comparison of phenology for the abundant 57 species. Bees were collected bi-weekly from the last week of April (Week 1) to the last week of September (Week 23) Table 4 List of species that changed between the common and rare 64 species groups or were collected in only one of the studies Table 5 Results of an ANCOV A test on the annual variation of genus 70 abundance Table 6 Summary of the ANCOV A test results on the annual variation 71 of the number of bees per species Table 7 List of the eleven species that showed a significant annual 72 variation pattern in abundance Table 8 Comparison of the number of bees collected per disturbance level 76 (low and high) in each year Table 9 Estimation of the total generic richness present over the four years 82 of the study, using the Abundance-based Coverage Estimator (ACE) and the Chao-l estimator Table 10 Estimation of the total species richness present over the four years 85 of the study, using the Abundance-based Coverage Estimator (ACE) and the Chao-l estimator • Table 11 The 95% confidence intervals for the observed number of genera 88 were estimated through a randomisation analysis that tested whether the number of genera varied among years Table 12 The 95% confidence intervals for the observed species richness 89 were calculated by a randomisation analysis that tested whether the species richness varied among years 7 LIST OF TABLES (Continued) Table Title Page Table 13 The annual change in genus and species 'c6mposition. The 90 computer program EstimateS used the Abundance-based Jaccard (Jabd) Index in order to analyse the similarity change among pairs of study years Table 14 Classification of core and satellite genera.