EFFECTS OF ABUNDANCE, DIVERSITY, AND HEALTH OF NATIVE POLLINATORS IN URBAN ...

99 Pages·2015·3.36 MB·English

EFFECTS OF ABUNDANCE, DIVERSITY,
AND HEALTH OF NATIVE POLLINATORS
IN URBAN FOREST FRAGMENTS

by

David P. Gardner

A thesis submitted to the Faculty of the University of Delaware in partial
fulfillment of the requirements for the degree of Master of Science in Entomology

Spring 2015

© 2015 David P. Gardner
All Rights Reserved
ProQuest Number: 1596851
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EFFECTS OF ABUNDANCE, DIVERSITY,
AND HEALTH OF NATIVE POLLINATORS
IN URBAN FOREST FRAGMENTS

by

David P. Gardner

Approved: __________________________________________________________
Deborah A. Delaney, Ph.D.
Professor in charge of thesis on behalf of the Advisory Committee

Approved: __________________________________________________________
Jacob L. Bowman, Ph.D.
Chair of the Department of Entomology and Wildlife Ecology

Approved: __________________________________________________________
Mark W. Rieger, Ph.D.
Dean of the College of Agriculture and Natural Resources

Approved: __________________________________________________________
James G. Richards, Ph.D.
Vice Provost for Graduate and Professional Education
ACKNOWLEDGMENTS
I would first like to thank Dr. Deborah Delaney, my academic advisor, for her
unwavering support, knowledge, and insight on this project. Thank you to Dr. Charles
Bartlett for his expertise in identifying insects, collection protocol, and vast knowledge
on insect families and their life history. I would like to also thank Dr. W. Gregory
Shriver for his advisement on statistical tests and modeling, fieldwork data, and to
better understand ecological processes. Thank you Dr. Vincent D’Amico for your
assistance in visualizing my data effectively and overall insight on FRAME-related
inquiries. I would also like to thank Dr. Sam Droege for his incredibly helpful and
incomparable assistance in identifying bees and collection protocol. Thank you
Desiree Narango for your assistance and support in understanding my statistical
analyses. Thanks to my entire lab, Katy Evans, Grace Savoy-Burke, Owen Cass, and
James Wolfin for their support both socially and with help in the field and in the lab.
Thank you to my assistants, Christina Mitchell, Cassandra Ference, Laura Manser, and
Janine Klosiewicz for their incredibly hard work, dedication, and involvement in my
project. Finally, I’d like to thank Jawuan Meeks for his support and assistance
throughout my graduate career.
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TABLE OF CONTENTS
LIST OF TABLES ....................................................................................................... vii!
LIST OF FIGURES ........................................................................................................ x!
ABSTRACT ................................................................................................................ xiii

Chapter

1 EFFECTS OF ABUNDANCE, DIVERSITY, AND HEALTH OF NATIVE
POLLINATORS IN URBAN FOREST FRAGMENTS.………………..…...….......1
!
1.1! Introduction ............................................................................................... 1!
1.1.1 ! Pollinator importance and decline ................................................. 2!
1.1.2 ! Pollinator diversity and behavior ................................................... 2!
1.1.3 ! Factors influencing pollinator health ............................................. 3!
1.1.4 ! Population genetics ........................................................................ 5!
1.1.5 ! Landscape effects on pollinators ................................................... 7!
1.1.6 ! Reliance on native bees ................................................................. 8!
1.1.7 ! Foraging behavior .......................................................................... 9!
1.1.8 ! Abundance and diversity ............................................................. 10!
1.1.9 ! Significance and rationale ........................................................... 11!
1.1.10! Hypotheses .................................................................................. 13!
1.1.11! Specific objectives ....................................................................... 13!
1.2! Methods ................................................................................................... 14!
1.2.1 ! Field sites ..................................................................................... 14!
1.2.2 ! Bowl trap samples ....................................................................... 18!
1.2.3 ! Aerial net samples ....................................................................... 19!
1.2.4 ! Flower samples and pollen analysis ............................................ 20!
1.2.5 ! Pesticide analysis ......................................................................... 20!
1.2.6 ! Genetic analysis ........................................................................... 21!
1.2.6.1! DNA Extraction ............................................................ 21!
1.2.6.2 ! Microsatellites .............................................................. 22!
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1.2.7 ! Statistical analysis ....................................................................... 23!
1.3! Results ..................................................................................................... 26!
1.3.1 Phenology .................................................................................... 32!
1.3.2! Beta diversity within sites ........................................................... 36!
1.3.3! Abundance modeling ................................................................... 37!
1.3.3.1! Andrena .................................................................... 38!
1.3.3.2! Andrena erigeniae ........................................................ 38!
1.3.3.3! Ceratina .................................................................... 39!
1.3.3.4! Halictidae .................................................................... 40!
1.3.3.5! Osmia .................................................................... 41!
1.3.3.6! Nomada .................................................................... 41!
1.3.4! Genetic analysis ........................................................................... 42!
1.3.5! Pesticide analysis ......................................................................... 47!
1.4! Discussion ............................................................................................... 48!
1.4.1! Species assemblage, richness, and phenology ............................. 49!
1.4.1.1! Assemblage .................................................................. 49!
1.4.1.2! Richness .................................................................... 52!
1.4.1.3! Phenology .................................................................... 54!
1.4.2 Floral resources ........................................................................... 55!
1.4.3! Beta diversity ............................................................................... 56!
1.4.4! Abundance modeling ................................................................... 57!
1.4.4.1! Andrena .................................................................... 59!
1.4.4.2! Andrena erigeniae ........................................................ 59!
1.4.4.3! Ceratina .................................................................... 60!
1.4.4.4! Halictidae .................................................................... 61!
1.4.4.5! Osmia .................................................................... 61!
1.4.4.6! Nomada .................................................................... 62!
1.4.5! Genetic analysis ........................................................................... 63!
1.4.6! Pesticide analysis ......................................................................... 65!
1.4.7! Conclusions ................................................................................ 67!
REFERENCES ............................................................................................................. 69!

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Appendix

A SUPPLEMENTARY GRAPHS ....................................................................... 78!

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LIST OF TABLES
Table 1.1: Fourteen field sites with five corresponding points and their coordinates
in Universal Transverse Mercator (UTM) format. .................................. 16!
Table 1.2: Variables collected within and around each field site with corresponding
mean and standard error. ......................................................................... 24!
Table 1.3: Models used to predict abundance including their multivariate
parameters. .............................................................................................. 24!
Table 1.4: Species count, ordered by the 20 most numerous species of 2013. 2014
species count displayed, and change between years with reductions in
red and additions in black. ....................................................................... 27!
Table 1.5: Genus count, 2013, 2014, and change between years with reductions in
red and additions in black. ....................................................................... 28!
Table 1.6: Genus count at Christina Creek 2, 2013, 2014, and change between years
with reductions in red and additions in black. ......................................... 28!
Table 1.7: Genus counts at Webb Farm, 2013, 2014, and change between years
with reductions in red and additions in black. ......................................... 29!
Table 1.8: Genus counts at White Clay 1, 2013, 2014, and change between years
with reductions in red and additions in black. ......................................... 29!
Table 1.9: Multivariate models ranked from best predicting Andrena abundance to
least using delta AIC values. Lambda coefficient values for each
covariate are indicated under each variable column. Most extreme
lambda values are the variables within the corresponding model that
best influence model performance (in bold). ........................................... 38!
Table 1.10: Multivariate models ranked from best predicting Andrena erigeniae
abundance to least using delta AIC values. Lambda coefficient values
for each covariate are indicated under each variable column. Most
extreme lambda values are the variables within the corresponding
model that best influence model performance (in bold). ......................... 39!
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Table 1.11: Multivariate models ranked from best predicting Ceratina abundance to
least using delta AIC values. Lambda coefficient values for each
covariate are indicated under each variable column. Most extreme
lambda values are the variables within the corresponding model that
best influence model performance (in bold). ........................................... 40!
Table 1.12: Multivariate models ranked from best predicting Halictidae abundance
to least using delta AIC values. Lambda coefficient values for each
covariate are indicated under each variable column. Most extreme
lambda values are the variables within the corresponding model that
best influence model performance (in bold). ........................................... 40!
Table 1.13: Multivariate models ranked from best predicting Osmia abundance to
least using delta AIC values. Lambda coefficient values for each
covariate are indicated under each variable column. Most extreme
lambda values are the variables within the corresponding model that
best influence model performance (in bold). ........................................... 41!
Table 1.14: Multivariate models ranked from best predicting Nomada abundance to
least using delta AIC values. Lambda coefficient values for each
covariate are indicated under each variable column. Most extreme
lambda values are the variables within the corresponding model that
best influence model performance (in bold). ........................................... 42!
Table 1.15: Average allelic and private allelic richness after rarefaction for Bombus
impatiens collected via sweep netting from seven forest fragments
located in northern Delaware and southeastern Pennsylvania (See
Table 1.1 for site abbreviations). Expected (H ) and observed (H )
E O
heterozygosity are averaged between all loci for each site. .................... 46!
Table 1.16: Average allelic and private allelic richness after rarefaction for Bombus
bimaculatus collected via sweep netting from six forest fragments
located in northern Delaware and southeastern Pennsylvania (See
Table 1.1 for site abbreviations). Expected (H ) and observed (H )
E O
heterozygosity are averaged between all loci for each site. .................... 47!
Table 1.17: List of all pesticides detected in pooled bee samples collected from six
FRAME sites (See Table 1.1 for abbreviations). LD = dosage of
50
chemical that kills 50% of honey bees, displayed in parts per billion
(ppb); N/A = Not Available, ND = Not Detected, MLOQ = Method
Limit Of Quantification,2 = Mullin et al 2010). All LD levels were
50
cited from University of Hertfordshire’s Pesticide Properties DataBase
(http://sitem.herts.ac.uk/aeru/ppdb/en/index.htm). .................................. 48!
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Table 1.18: Eight microsatellite markers used to test genetic diversity in Bombus
impatiens and Bombus bimaculatus and their corresponding
information (Jonathon Koch, personal communication). Tag: marker
dye color, Range: range of microsatellite length in base pairs, Motif:
core sequence, T: annealing temperature. ............................................... 78!
Table 1.19: All bees collected from bowl traps in northern Delaware (refer to Table
1.1 for site abbreviations). Values indicate mean number of bees
collected during each visit (total of 18 visits), with the standard error
in parentheses. ......................................................................................... 79!
Table 1.20: Flowers visited by bees, separated by pollinator genus, 2013 and 2014
collectively. Flower names are ordered from most commonly to least
commonly visited within each bee genus. ............................................... 84!

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