Assessment of Floristic Quality and Plant-Pollinator Interactions on Powerline Right-Of-Way at Lillian Anderson Arboretum

Assessment of Floristic Quality and Plant-pollinator Interactions on Powerline Right-of-way at Lillian Anderson Arboretum

Amy M. Cazier

RESEARCH SUPERVISOR

Dr. Ann Fraser, Ph.D. Professor of Biology, Kalamazoo College Kalamazoo, MI

FACULTY SUPERVISOR

Dr. Santiago Salinas, Ph.D. Professor of Biology, Kalamazoo College, Kalamazoo, MI

A paper submitted in partial fulfillment of the requirements for the degree of Bachelor of Arts at Kalamazoo College

2020 Acknowledgments

I would like to thank Dr. Ann Fraser for her guidance and expertise in helping to construct this study and her support along the way as well as Russ Schipper for his enthusiasm and help with identifying many forbs of the Arb! This research would not have been possible without the Center for Environmental Stewardship for funding my research and their excitement for the project. I would like to thank the Kalamazoo Biology Department faculty for their continuous support and the other students working in Dr. Fraser’s lab: Trevor Rigney, Nicki

Bailey, and Niko Nickson for their assistance throughout the research project. Lastly, I would like to thank those involved in the review process, Dr. Sara Tanis, Alex Kaufman, Mathew

Holmes-Hackerd, Maggie Schaefer, Basha Williams, and Liam Fries

Table of Contents

Acknowledgments……………………………………………………………………………….. ii

Table of Contents…………………………………………………………………………………iii

List of Tables……………………………………………………………………………………. iv

List of Figures……………………………………………………………………………………. v

List of Appendices………………………………………………………………………………. vi

Abstract…………………………………………………………………………………………... 1

Introduction………………………………………………………………………………………. 2

Materials and Methods…………………………………………………………………………...11

Results……………………………………………………………………………………………18

Discussion………………………………………………………………………………………..39

Literature Cited…………………………………………………………………………………..48

iii

List of Tables

Table I. Catalog of Plant Species’ Characteristics and Maximum Abundance………………….19

Table II. Section Comparison of Plant Species Percentage of Richness and Physiognomy ……21

Table III. Section Comparison of Percent Annuals, Perennials, and Biennials……………….…25

Table IV. Number of Plant Species Visited by Pollinators in BW, NM, and MP Locations……27

Table V. Connectance Metric of BW, NM, and MP ……………………………………………31

Table VI. Number of Native and Adventive Plant Species Visited by Pollinators ……………..32

List of Figures

Figure 1. Map of the Six Sections of Lillian Anderson Arboretum Powerline ROW…………...12

Figure 2. Percentage of Native and Adventive Flowering Species on Powerline ROW………...22

Figure 3. Comparison of Section Averages of Coefficient of Conservatism……………………23

Figure 4. Comparison of Section Averages of Wetness Coefficient…………………………….24

Figure 5. Plant-pollinator Interaction Network of Location BW………………………………..28

Figure 6. Plant-pollinator Interaction Network of Location NM………………………………..29

Figure 7. Plant-pollinator Interaction Network of Location MP………………………………...30

Figure 8. Plant-pollinator Interaction Network of Native Flowering Plant Species……………..33

Figure 9. Plant-pollinator Interaction Network of Adventive Flowering Plant Species…………34

Figure 10. Comparison of Focal Plant Visitors Sorted by Order………………………………...36

Figure 11. Comparison of Focal Plant Gernera of Bee Visitors…………………………………37

List of Appendices

Appendix A………………………………………………………………………………………52

Appendix B………………………………………………………………………………………60

Abstract

Populations of pollinators, and more specifically bees have declined recently and due to their vital roles in our ecosystems and agriculture industry (Potts et al., 2010). Efforts to protect, conserve and even enhance their abundance and diversity have become a global concern. One way to promote pollinator populations involves providing the floral resources of which they are reliant on for nutrients and successful reproduction (Wratten et al., 2012). A pollinator habitat enhancement project is scheduled to begin on the powerline right-of-way (ROW) at Kalamazoo

College’s Lilian Anderson Arboretum. Before the implementation of such projects, it is useful to establish a baseline understanding of what floral resources are already present and the characteristics of current plant-pollinator interaction networks in order to measure changes after enhancement is underway. A systematic floral survey was conducted and identified 117 species of flowering plants on the powerline ROW. This survey informed required management needs of the area before the successful seeding of new floral resources could occur and identified areas on the powerline ROW which were unique representations of a pre-settlement environment and should left alone in respect to adding new flowering plant species. Plant-pollinator interaction metrics showed overall generalist qualities of current networks and revealed specialist traits of the plant Stachys hyssopifolia (Hyssop Hedgenettle) and the genera Bombus (bumble bees).

Focal plant-pollinator interactions demonstrated many current flowering plant species rely on bumble bee pollinators for reproduction and that further work should be done to better understand bumble bee habits and enhance their habitats.

Introduction

In recent years the concern over pollinator population declines has increased and garnered attention worldwide. Pollinators play an integral role in plant reproduction and as a result have large impacts on the agriculture industry and biodiversity starting at the level of primary producers (Mader et al., 2011). Biotic pollinators are considered to be any organism that delivers the male gametophyte of a flowering plant to the stigma (female reproductive part of a flower) of a different plant of the same species (Mader et al., 2011). While some flowering plants can self-pollinate or can use wind pollination, animal facilitated cross-pollination aids in 90% of flowering plants for fertilization (Bauer & Wing, 2010; Kearns et al., 1998). In an environment, there are plant and pollinator species that are ecological specialists and generalists. Specialist species have a low number of interaction partners and generalists have a high number of interaction partners relative to the environment (Ferry-Graham et al. 2002). The majority of flowering plants are reliant on pollinators to transport pollen from one flower to another of the same species stigmatic surface so that fertilization can occur.

Pollinators are often responsible for pollen delivery to another plant because the plant is a resource essential to their survival, often in the form of food. Hummingbirds, bats, spiders, and a wide range of insects such as beetles, flies, butterflies, moths, ants, wasps, and bees are pollinators. While hummingbirds and bats can be effective pollinators, they tend to specialize in certain types of flowers (Wojcik and Buchmann, 2012). In fact, insects account for a great amount of the pollination services flowering plants need. In Europe, 84% of crop species are directly dependent on insect pollinators (Williams, 1994). Certain families within Coleoptera and

Diptera can be very effective pollinators due to their exposure to pollen. Both flower flies

(Family: Syrphidae; Order: Diptera) and bee flies (Family: Bombyliidae; Order: Diptera) feed on

2 floral nectar and pollen (bee flies also have hairy bodies capable of carrying significant amounts of pollen. Moths and butterflies (Lepidoptera) generally feed on flower nectar but in the process, pollen can be transferred to another flowering plant via proboscis or pollen deposited on their wings (Holm, 2014). Wasps tend to only feed on a flower’s nectar as well, and while they are far less hairy than bees, some, like the Masarinae (Hymenoptera: Vespidae) are excellent pollinators because their offspring require pollen for nutrients, and the parents accidentally pollinate during pollen collection (Wojcik and Buchmann, 2012).

Bees are considered to be the predominant pollinators because nectar and pollen are essential to the survival of adults and the development of larvae (Sedivy et al., 2011). Pollen is the primary source of bee protein and bees have adapted ways that enable effective pollen collection (Thorp, 2000). Many bees have scopae, specialized hairs grouped together on their legs and abdomens for dry pollen collection (Kuhlmann, 2006). These adaptations help to facilitate pollen transfer from anther to stigma. Both honey bees (Apidae: Apis mellifera) and wild bees are vital to the agriculture industry. As a eusocial species, meaning they exhibit cooperative brood care, overlapping generations, and division of reproductive labor, honey bees are more accessible for facilitating agriculture production; hives can be raised and transported from crop to crop. Honey bees are valued at $1.6-$5.7 billion in the United States annually, calculated from crop production (National Research Council, 2007). However, it has become more apparent that native wild bees not only contribute to pollination services and can be more effective than those specifically raised for commercial use. In more than 40 percent of crops grown worldwide, wild pollinators improved pollination efficiency. For example fruit set was increased two times that which was pollinated by honey bees (Garibaldi et al., 2013).

Many of the crops humans rely on are produced with pollinator assisted facilitation. In

2005 the worldwide economic value of pollination amounted to $167 billion, approximately

9.5% of agriculture production used for human food (Gallai et al., 2009). Declines in pollinator populations will negatively impact agriculture production and ultimately affect the global economy. The concern in the agriculture industry over the threat of decreased pollination services increased when managed honey bee hives began to experience colony collapse disorder

(CCD) (Winfree et al., 2009). In recent years the worry over the effects CCD will have on food security, meaning reliable access to affordable and nutritious food has initiated further research into the factors that can negatively impact bees. In 2006 when some U.S. honey beekeepers reported 30-90% colony losses, the term CCD was created to describe what was happening to honey bee colonies. The sudden loss of honey bees initiated research into the array of potential causes of CCD and subsequently the concern over the status of all pollinators (Ellis et al., 2010).

While managed honey bees can account for much of crop production wild, solitary bees (bees that live alone) also play an important role in agriculture and the diversity of ecosystems (Potts et al., 2010). In fact, the majority of crop pollination worldwide is performed by wild pollinators rather than honey bees (Goulson et al, 2015).

Plants and pollinators experience a beneficially mutualistic relationship that has shaped the characteristics of both types of organisms over time. As a result of this coevolution, both have increased diversity over time and ultimately the biodiversity of their ecosystems

(Bascompte et al, 2006). Pollinator diversity is important to both crop production and maintenance of biodiversity. Specialist plant species that interact with specialized pollinators are more prone to extinction than a specialized plant species interacting with generalist pollinators.

(Stang et al., 2006). Abundance and diversity of pollinators in an environment increases the

4 likelihood of plant fertilization. Plant fertilization whether for a crop or members of an ecosystem is important to the overall habitat. More successful fertilization yields more food production and therefore food security. Effective and diverse pollination in an ecosystem benefits a wide range of organisms, as the more reproductively successful plants are, the more resources there are for organisms of all trophic levels (Bommarco et al., 2013). The greater the amount of resources available in a habitat the greater the diversity and resiliency of its ecosystem.

In the last few decades managed bees, wild bees and other pollinators have experienced declines (Goulson et al., 2015). As a result, flowering plants reliant on pollinators have experienced parallel declines (Potts et al., 2010). These declines cannot be attributed to one cause, but the majority are due to anthropogenic disturbances including habitat fragmentation, habitat loss, pesticides, pathogens and parasites, and climate change (Bommarco et al., 2013).

Agrochemicals such as insecticides and herbicides can negatively affect pollinator diets, harming the organism by depleting their resources and access to them. Herbicides can be used to effectively eliminate weeds, therefore reducing the diversity of floral resources, contributing to habitat loss. Additionally, due to the seed application of pesticides, 161 pesticides have been consumed by honey bees and appear in honey analysis (Sanchez-Bayo & Goka, 2014). This consumption can lead to a range of defects including attacks on the nervous system which cause paralysis and death (Tomizawa & Casida, 2005).

Eusocial bees, in particular, have been subject to greater than normal amounts of parasites and diseases. This can be partly attributed to their role in agriculture, honey bees and bumble bees are transported to different geographic locations for their pollination services and are liable to carry parasites and diseases with them to areas that would not have otherwise been

5 introduced. For example, a 2006 study found two genetically different parasitic tracheal mites originating in Japan and Europe to be in the other region after bumblebee importation for commercial use (Goka et al.). When pathogens and parasites are introduced to an ecosystem that has not evolved mechanisms to combat their effects, the impact has the potential to be even greater (Chen et al., 2009).

Habitat loss and fragmentation is a large contributor to pollinator declines and is considered to be one of the primary causes of their population loss. Pollinator reliance on floral resources means that significant loss of floral diversity in a habitat will make the area uninhabitable (Winfree et al., 2009). Pollinators with more specialized diets are more vulnerable to habitat loss as their nutrient sources are limited. A study that compared multiple specialist bee species to multiple generalists found that there was less gene flow among the specialist species due to the inherent isolation which occurs among specialists and are therefore at greater risk of extinction (Zayed et al., 2005). A given habitat may still have substantial flower abundance and richness yet is insufficient for a certain pollinator if specific resources are unavailable. Generalist pollinators are still vulnerable to habitat loss because it is necessary for floral resources to be within foraging distance of their nests. Foraging range is correlated with bee body size, and smaller bees are therefore more vulnerable to habitat loss and fragmentation (Greenleaf et al.,

2007). In addition, habitat fragmentation not only limits resources, it limits breeding and consequently decreases the genetic pool. Habitat fragmentation has adverse effects on the reproductive success of flowering plants as well because the resulting isolation of their population decreases bee populations which in turn decreases plant pollination (Kolb, 2008).

There are measures that can stop and potentially even reverse pollinator declines. These include avoiding the use of pesticides harmful to bees and other insects, as well as the provision

6 of suitable nest sites and food resources (Winfree, 2010). Pollinator habitat enhancement projects involve increasing the abundance and richness of flowering plants as pollinators depend on their resources for survival and reproduction. Multiple studies have found that enhancing abundance and diversity of floral resources on farmland has a positive effect on bee abundance (Wratten et al. 2012). Greater flower diversity and abundance have additional benefits to the ecosystem, including soil and water quality protection as well as the reduction of pest populations, (Wratten et al. 2012).

Pollinator habitat enhancement projects have been implemented in areas that already receive regular maintenance such as agriculture fields and their edges, roadside verges, parks, private residences, median strips and powerline right-of-ways (ROWs) (Wratten et al., 2012).

Powerline ROWs are ideal locations for pollinator habitat enhancement projects as they are an anthropogenic source of habitat fragmentation and need to be constantly maintained (Wojcik and

Buchmann, 2011). Powerline ROWs cover a considerable amount of area in the United States, nearly as much area that is protected by National Parks. A study conducted by Russell et al. concluded that there is a potential for ROWs providing 5 million acres of bee-friendly habitat

(2005). Currently, most powerline ROWs are maintained at the discretion of utility companies, usually consisting of mowing, tall vegetation removal, and application of selective herbicides

(Russell et al., 2005). Flower plantings can fill fragmented areas and connect habitat previously separated, effectively providing more floral resources and reducing the impact of fragmentation

(Yahner, 2004). The promotion of local native wildflowers was found by Hopwood to create a habitat in which is actively foraged by bumble bees and other native bees (2008). Powerline

ROWs are an ideal site for enhancement because the need to maintain low vegetation allows sunlight to reach the ground. Insects as ectotherms rely on the environment to help maintain their

7 body temperature and exposure to sunlight is utilized to warm the body for flight (Wojcik &

Buchmann, 2012). Additionally, the bare soil that results from medium level of disturbance that occurs along ROWs is used for solitary ground-nesting bees (Holm, 2014).

Kalamazoo College’s Lillian Anderson Arboretum (LAA) located in southwest Michigan has a powerline ROW running through the property. The ROW occurs along a transition area of ecosystems and is home to many flowering plants including forbs (herbaceous broad-leafed, woody plants) shrubs (plants with woody stems), and trees (Oregon State University, 2016).

Until recently the powerline ROW was managed by the utility company Consumers Energy, which contracted out the vegetation management which consisted of cutting tall vegetation and herbicide application approximately every five years. During the intervening years, Kalamazoo

College mows the centerline strip where a trail (Powerline Trail) is located. A pollinator habitat enhancement project is scheduled for LAA along the powerline ROW. Site preparation is to begin in the summer of 2019, with the goal of seeding wildflowers in the winter of 2019.

The land of the LAA previously kept livestock including cows, chickens, and pigs and used for agriculture, producing rye, corn, oats, wheat, hay, clover and potatoes but came to a stop after close to 100 years in 1936 (Mickus & Bunker, 2015). Around the time the land stopped being used for crop production, much of the area became the site of a pine plantation. In 1998

Kalamazoo College came to own the LAA and created trails throughout the 140 acres site. The

LAA is used by the college for education, research, recreation and is open to Kalamazoo residents and visitors (arboretum.kzoo.edu, accessed July 2019). A natural history survey of the

LAA conducted attributed much of the high plant diversity found on powerline ROW to the multiple farm fields it once occupied (Mickus & Bunker, 2015). The natural history survey only documented a total of 31 flowering plant species along the powerline ROW likely due to the

8 short amount of time spent collecting data. This study instead regularly surveyed the powerline

ROW on a weekly basis starting once the first flowers bloomed for the season in order to systematically document flowering species of different phenologies.

This study was conducted to assess the current floral resources available to pollinators, to determine which pollinators were utilizing the resources of which flowering plants and conversely which flowering plants were being visited by which pollinators for reproduction before the habitat enhancement project is underway. A floristic quality assessment was determined by the corresponding coefficient of conservatism value for each flowering species using the method developed by Swink and Wilhelm (1994) to evaluate relative floristic quality.

Bee abundance and diversity in the LAA has been recorded during the months between May and

September since 2008, using a variety of collection methods consisting primarily of bee bowls, blue vane traps. Floral and bee assessments individually help to inform the status of the habitat before enhancement, establishing a knowledge base of what species are present and what areas have the potential for improvement. In addition, the evaluation of plant-pollinator interactions pre- and post-enhancement provide useful information concerning community structure.

Elements of the plant-pollinator mutualist relationship such as the degree of specialization and robustness in response to biological diversity are revealed in network analysis (Blüthgen et al.,

2006 and Fontaine et al., 2005). The identification of critical factors of the habitat are used to identify core plant species that are visited by pollinators and inform designs for wildflower plantings providing optimal resources for desired pollinators (Robson, 2014). Plant-pollinator interactions networks were created from data collected via transect observations in order to incorporate information on floral abundance which offers a more accurate and comprehensive representation of the network while separate stationary timed observations provided data on

9 potential pollinators of floral species which increase the floristic quality of the habitat (Gibson et al., 2010).

Materials and Methods

Study Site

This study was conducted on the powerline ROW at the Lillian Anderson Arboretum (LAA) located in Oshtemo Township, Kalamazoo County, Michigan (42⁰17’44.0” N, 85⁰42’06.6” W)

(Fig. 1). The powerline ROW was placed in 1946, running approximately 700 meters along a transition area of coniferous forest prairie and wetland ecosystems. The powerline ROW is a narrow strip (~35 meters wide) with the “Powerline Trail” running roughly through the center.

The trail has been seasonally flooded in 2017, 2018, and 2019 and the area named Rivera Pond when present from February through July during which time it reaches approximately 75-150 meters long.

Plant Surveys and Floristic Quality Assesment

Figure 1. Map of the Six Sections of Lillian Anderson Arboretum Powerline ROW Map of the six sections differentiated for floristic quality assessment of the Lillian Anderson Arboretum powerline ROW (~700 meters long by ~35 meters wide) in Oshtemo Township, Kalamazoo County, Michigan (42⁰17’44.0” N, 85⁰42’06.6” W) divided into six sections (A, B, C, D, E, and F) which varied in length for the purposes of this study and are shown by the different colored lines. Summer of 2019.

I cataloged the diversity of the flowering plants (including forbs, shrubs, and trees) available to pollinators along the powerline ROW by conducting a weekly survey beginning in May and extending through the end of August of 2019. Plant presence was only recorded for those species in bloom at the time of each survey to document plants flowering phenology. The survey area was divided into six sections (A-F) with start and end points determined by trails and other landmarks intersecting the ROW. The sections and their approximate length were as follows: A)

Wetland Boardwalk - Fern Oak (~70 meters); B) Fern Oak - Not-So-Magnificent Pines (~135 meters); C) Not-So-Magnificent Pines - Rivera Pond (~115 meters); D) Rivera Pond -

Magnificent Pines (~95 meters); E) Magnificent Pines – Gathje Hill (~60 meters); and F)

Gathje Hill – Batts Pond (~105 meters) as shown in Figure 1. During a survey, I would systematically walk through the length and width of a section, identify and record all flowering species. It would take roughly an hour to an hour and a half to complete a section after which I would record the relative abundance of each plant within each section was recorded on a scale of

1 to 5 as follows: 1 = rare, 2 = uncommon, 3 = common, 4 = abundant, and 5 = very abundant.

Rare abundance was classified as at least one plant present, uncommon was considered to have

5-10 plants present, common was considered to have more than 10 plants which were found in multiple places within the section, a plant was considered to be abundant if it was found regularly throughout the entire section, and plants were considered very abundant if they covered the area completely.

Sections were distinguished so data recording Flowering plants were identified in the field using Newcomb's Wildflower Guide (Newcomb, 1977) and Gleason’s Plants of Michigan: A

Field Guide (Rabeler, 1998). Every identified plant was photographed with identifying floral and leaf characteristics visible to be incorporated into the Lillian Anderson Arboretum website.

In the event the plant could not be identified in the field, samples were taken and examined in the lab or taken to a local botanist, Russ Schipper for consultation. A database of observed plant species was constructed and contained the following information: common name, Latin name, wetness coefficient, wetness index, physiognomy, coefficient of conservatism, conservation status, family, flower color, whether it is considered native or adventive (i.e. introduced to the area post-European settlement) to Michigan, and if it can grow in disturbed habitats, according to

Michigan Flora, University of Michigan’s online herbarium (michiganflora.net, accessed May-

September 2019). If the species could not be identified, flower color and genus or family was recorded and a morphospecies name was assigned.

To establish a baseline of the quality of the area before the future habitat enhancement has begun, a Floristic Quality Index (FQI) was calculated for each section and then for the entirety of the powerline ROW using the online Universal Floristic Quality Assesment (FQA) Calculator

(Freyman et al., 2016). FQA is calculated with the coefficient of conservatism (C) which is a numerical representation of a plant species’ tolerance to degradation and the degree to which the species is faithful to natural remnant habitats (Freyman et al., 2016). Coefficient of conservatism values ranged from 0 to 10 where higher values were less tolerant of degradation and have more fidelity to presettlement habitats. Adventive plants were assigned a coefficient of conservatism value of zero.

General Plant-pollinator Interaction Surveys

To document what floral resources pollinators were utilizing and which floral visitors each flower species is receiving I conducted 15-minute plant-pollinator interaction surveys along the powerline ROW from June through August of 2019. Interaction surveys took place in three locations, which in total covered nearly the entire length of the powerline ROW, beginning at the

Boardwalk (BW), Not-So-Magnificent Pines (NM) and Magnificent Pines (MP) trail intersection points with the Powerline Trail and the length parallel to the trail of the meters wandered was recorded. These surveys involved walking a wandering transect (i.e. not orthogonal) through the powerline ROW, recording all visible flowering species in bloom, their relative abundance as rare, uncommon, common, abundant, and very abundant, and any potential pollinator observed near the reproductive organs of the plant then classified more specifically based on morphological characteristics. Pollinators were identified as either bee or non-bee then further classified to insect order in the field. Categories of bees were honey bee, bumble bee, chap leg bee, tiny dark bee, tiny dark with stripes bee, green sweat bee, medium dark bee, medium dark with stripes bee, striped hairy belly bee, metallic hairy belly bee, and cuckoo bee. The relative cloud coverage (clear, partly cloudy, or bright overcast), light exposure (shade, parts shade, full sun), wind direction, starting point, side of trail, and distance wandered were recorded for each transect using the Avenza Maps application (Avenza Systems Inc., 2019). The mean values of the temperature, wind speed, and relative humidity over the course of the 15-minute wandering transect were gathered from the Enviroweather station for Oshtemo, Michigan located in LAA

(Enviroweather Oshtemo Michigan, 2019).

Using the data from general plant-pollinator interaction surveys interaction plots were generated in R Studio (version 1.1.463) using the package, bipartite. Before subjecting data to bipartite analysis a Principle Comparison Analysis (PCA) verified that there were no extreme combinations of abiotic factors during data collection that might call for the exclusion of any potential pollinators. Any potential pollinator observed in less than five interactions during general plant-pollinator surveys was excluded from analysis of all networks because the data was considered too small to show significant patterns. Any flowering plant observed less than five

15 times to have received a potential pollinator was excluded from all network analysis because the data was considered too small to show significant patterns. The interaction networks were constructed for the three plant-pollinator interaction survey areas and separate networks for the flowering native and adventive plants. A two-tailed t-test comparing the number of visitors of each morphological group to native and adventive flowering plant species was conducted to test if the number of potential pollinators differed among native and adventive plants. Each interaction networks’ weighted nestedness: a measure of network stability based off linkage structure, connectance: the realized proportion of links, H2: the degree of specialization, and interaction evenness: a measure of the homogeneity of interaction frequencies, Shannon

Diversity Index to measure the diversity of interactions was analyzed.

Focal Plant-pollinator Interaction Surveys

Certain flowering species with higher coefficients of conservation were selected for focal surveys of visitors. Depending on the abundance of the focal plant species, one of two methods was used to survey the plant-pollinator interactions: the first method referred to as wandering surveys, was used when flowering species of interest were considered to be abundant and pollinators easily seen while moving. The collector wandered for 15-minutes and collected any visitor found near the center of the flower in order to identify the plants’ potential pollinators at the species level. If the plant of interest could no longer be found during the wandering transect, the time was paused and resumed once the plant species became visible again.

The second method referred to as stationary collection was used when the abundance of the flowering species of interest was considered common or less than common. Locations for the stationary collection were determined by the ability to observe the greatest number of the specific plant at one time. Multiple locations were chosen for each plant, except in the event

16 when only one location was in bloom. The collector stood approximately 1 meter away from the closest plant(s), with all easily visible, waited one minute before beginning the collection period during which any potential pollinator was gathered. In the event a queen bumble bee was observed on the plant species of interest, time was paused while the bee was photographed, after which sampling was resumed. Three collections were conducted for each forb species. A SKIL

18V cordless vacuum 2810 (BioQuip Inc) and attached canisters (approximately 12.5 cm long with a 5.1 cm diameter) designed to prevent any potential pollinators from crawling out were used for collection.

Canisters were taken back to the lab where specimens were euthanized via freezing or ethyl acetate. Specimens from each collection were then pinned and separated into groups of bees and non-bees. Bees were identified using the online Apoidea Species Guides at discoverlife.org and verified by Dr. Ann Fraser (Ascher et al.; http://www.discoverlife.org; accessed June 2019).

Non-bees were identified using Insects: Their Natural History and Diversity: With a

Photographic Guide to Insects of Eastern North America (Marshall, 2017), the Google Lens application on the Google Pixel 2 phone, and verified by Dr. Ann Fraser (Google LLC, 2019).

Results

Floristic Quality Assessment

A total of 117 different flowering plant species in bloom (forbs, shrubs, and vines) were cataloged. Of these, 109 of which were identified to species, five were identified to family and were given morphospecies names. The remaining three were only identified to genus level

(Antennaria, Solidago, and Rubus). In the case of Solidago and Rubus, multiple species were present but it was too difficult to differentiate species, so they were grouped together under the genus. Every recorded flowering plant’s physical characteristics were cataloged, maximum abundance over the course of the study and its average were calculated (Table I). Rubus flagellaris (Northern Dewberry), was distinguishable from other species of Rubus and was found to have the greatest average of maximum abundance on the powerline ROW: 4.33.

Table I. Catalog of all plant species observed flowering along the Powerline ROW during systematic floristic quality surveys conducted between May and August, 2019. Species are sorted by family and listed alphabetically under the family. The common name (or morphospecies), Latin name, family, Coefficient of conservatism (C), Wetness coefficient (W), physiognomy (A-Forb stands for annual forb, B-Forb stands for biennial forb, and P-Forb stands for perennial forb), maximum abundance in each of the six survey sections recorded over the course of the study, flowering period, and color of the flower are shown as wh: white, pk: pink, or: orange, bl: blue, pu: purple, yw: yellow, li: lilac, red, and gn: green. Color Species are shown as native by “N” and adventive by “A”. Coefficients of conservatism values range from 0-10 if a native species, adventive species have a * in place of a value between 0 and 10. The numbers within the “Survey period when flowering” heading represents the week number which flower surveys were conducted (columns for weeks 2 and 3 are greyed out because surveys were not conducted). * Table with all 117 flowers can be found in the appendix A.

Survey period when flowering Survey Section May June July August max. abundance

Plant family and species Common name/ morphospecies Color Native? C W IndexWet Physiognomy Avg. Abun. A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

APIACEAE B- Daucus carota Queen-annes-lace wh A * 5 UPL 2.67 3 3 3 3 4 x x x x x x x x x Forb ASTERACEAE P- Achillea millefolium Yarrow (white) wh N 1 3 FACU 2.33 1 2 2 3 3 3 x x x x x x x x x Forb Chrysanthemum P- Oxeye Daisy wh A * 5 UPL 2.5 3 3 3 3 3 x x x x x x x x x leucanthemum Forb B- Erigeron annuus Daisy Fleabane wh N 0 3 FACU 3 2 4 3 2 3 4 x x x x x x x x x x x Forb P- Erigeron strigosus Lesser Daisy Fleabane wh N 4 3 FACU 2.17 3 3 2 2 3 x x x x x x x x x x Forb P- Hieracium caespitosum Yellow Hawkweed yw A * 5 UPL 2.5 2 3 3 3 2 2 x x x Forb P- Hypochaeris radicata Cats Ear yw A * 3 FACU 3.5 3 3 4 4 4 3 x x x x x x x x x x x x x Forb P- Krigia biflora Cynthia yw N 5 3 FACU 1 3 3 x x x x Forb P- Rudbeckia hirta Black-eyed Susan yw N 1 3 FACU 1.67 2 2 3 3 x x x x x x x x x x Forb - False Wild Lettuce yw 2.5 3 3 3 3 3 x x x x x x x x x x

EUPHORBIACEAE

Survey period when flowering Survey Section May June July August max. abundance

Plant family and species Common name/ morphospecies Color Native? C W IndexWet Physiognomy Avg. Abun. A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

P- Euphorbia corollata Flowering Spurge wh N 4 5 UPL 2.17 2 3 3 3 2 x x x x x x x x x x Forb FABACEAE P- Baptisia lactea White False Indigo wh N 9 3 FACU 0. 33 2 x x x Forb HYPERICACEAE P- Hypericum perforatum Common St Johnswort yw A * 5 UPL 2.17 2 2 3 3 3 x x x x x x x x x Forb P- Hypericum punctatum Spotted St Johnswort yw N 4 0 FAC 3 3 3 3 3 3 3 x x x x x x x x x Forb LAMMIACEAE P- Prunella vulgaris Heal-all pu N 0 0 FAC 1.5 2 3 1 1 2 x x x x x x x x x x Forb P- Stachys hyssopifolia Hyssop Hedgenettle li N 10 -3 FACW 2.83 3 4 4 3 3 x x x x x x x x x Forb MYRSINACEAE P- Lysimachia quadrifolia Whorled Loosestrife yw N 8 3 FACU 2.83 5 4 4 4 x x x x x x Forb ROSACEAE P- Potentilla simplex Common Cinquefoil yw N 2 3 FACU 3 3 3 3 2 4 3 x x x x Forb Rubus flagellaris Northern Dewberry wh N 1 3 FACU Shrub 4.33 4 5 5 5 4 3 x x x x x x

Plant species richness within each section ranged from 49 to 77 species (Table II). The majority of flowering species along the powerline ROW and in each section were forbs. Only six species of shrubs and two species of vines were found along the entire powerline ROW, the remaining cataloged plants were forbs (Table II). Section A and Section E had the lowest species richness of the flowering plants along the powerline ROW (Table II).

Table II. Species richness of plant species flowering at the time of the survey, followed by their percentage breakdown by growth habit (forbs, shrubs, and vines) for each of the six survey sections along the powerline right-of-way and for the entire powerline.

Species Powerline Section Richness Forbs (%) Shrubs (%) Vines (%) A 45 93.3 6.7 0 B 70 92.9 5.7 1.4 C 63 93.4 3.3 3.3 D 51 95.9 4.1 0 E 45 95.3 4.7 0 F 56 96.3 3.7 0 Entire Powerline 109 92.7 5.5 1.8

Of the identified flowering species 67% were native to Michigan and the six sections ranged from 57.4% to 80% native flowering species (Figure 2). Section A, the section closest to the nearby highway had the highest percentage of native flowering plant species. As the section gain distance from the highway (from north to south), the percentage of native plants decline, with the exception of Section E having a slightly greater percentage of native species (62.8%) than Section D (59.2%). (Figure 2).

100%

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50%

40%

30%

20%

Percent Percent of Native and AdventiveSpecies 10%

0% A B C D E F Entire Powerline Powerline Right-of-Way Section

Native Species Adventive Species

Figure 2. Stacked bar graph showing the percent of native and adventive flowering species in the entire powerline ROW and in each of the six sections.

The section that had the highest mean coefficient of conservatism (퐶̅) was Section A

(3.53 ± 2.77) and the lowest 퐶̅ was Section F (1.53 ±2.28). The 퐶 of the powerline ROW was

2.64 ± 2.77, while the 퐶̅ of each section decreased the further south each section was. The difference between the 퐶̅ of the six different sections was statistically significant as shown by an analysis of variance analysis (ANOVA) (F (5, 316) = 3.99, p = 0.002). The 퐶̅ difference between

Section A and Section D, Section A and Section E, and Section A and Section F were statistically significant as shown by Tukey Honest Significance Difference (Tukey HSD) analysis. (Figure 3).

4.5 a 4 3.5 3 2.5 b b 2 b 1.5 1 0.5 0 Coefficient Coefficient of Conservatism A B C D E F Powerline ROW Section

Mean C Entire Powerline C

Figure 3. Comparison of flowering species coefficient of conservatism (C) values for each survey section. Values shown as means ± SE. The dashed line represents the coefficient of conservatism for the entire Powerline ROW (2.64 ± 0.25). Bars not sharing the same letter differ significantly, Tukey HSD, p < 0.05.

The section of lowest mean wetness coefficient (푊 ), the lower the W value, the greater the wetness ideal for the associated plant species, was Section A and the highest was Section E.

The 푊 of the powerline ROW was 1.50 ± 0.14. The difference between the 푊 of the six different sections was statistically significant as shown by an ANOVA (F (5, 305) = 3.99, p = 0.003). The

푊 difference between Section A and Section C, Section A and Section D, Section A and Section

E, and Section A and Section F were statistically significant as shown by Tukey HSD analysis.

(Figure 4).

3 b b b 2.5 b

1.5

1 a Wetness Coefficient 0.5

0 A B C D E F Powerline ROW Section

Mean Entire Powerline ROW

Figure 4. Comparison of plant wetness coefficient (W) values for each survey section. Values shown as means ± SE. The dashed line represents the wetness coefficient for the entire Powerline ROW (1.50 ± 3.18). Bars not sharing the same letter differ significantly, Tukey HSD, p < 0.05

Most of the flowering plant species found on the powerline ROW were perennials, flowers that bloom every year (75.2%), annuals, flowers that only bloom once a year, made up

15.6%, and biennials, flowers that have a two-year life cycle were the remaining 9.2%. Section A had the highest percentage of perennials (84.4%) and native perennials (64.4%) while Section D had the lowest percentage of perennials (65.3%) and native perennials (42.9%) (Table III).

Table III. The number of annual, perennial, and biennial of flowering species recorded on the powerline ROW and distinguished by section.

Powerline Section Annual Perennial Biennial A 5 38 2 B 11 51 8 C 10 43 8 D 10 32 7 E 7 30 6 F 9 37 8 Entire Powerline 17 82 10 ROW

General Plant-pollinator Interaction Surveys

We recorded 635 potential plant-pollinator interactions on 42 flowering plant species under the powerline ROW, 586 potential plant-pollinator interactions with 18 flowering plant species after the exclusions of pollinators and plants with less than five interactions observed.

The most common pollinator group observed when looking at all three locations (BW, NM, MP) were the medium dark bees with stripes (n = 11, n = 46, n = 53). At the BW, NM, and MP locations 11, 46, and 53 medium dark bees with stripes were observed at 5, 13, and 13 different flowering plant species respectively (Table IV and Figures 5, 6 and 7). The size of plant- pollinator networks of the BW, NM, and MP locations was relatively similar, BW had the smallest number of plant species and pollinator groups combined for a total of 25 while NM and

MP both had 30 total groups of organisms (Figures 5, 6, and 7). Hemiptera was amongst the top three visitors in all three locations: first, second and third for BW, NM, and MP respectively and

Diptera was also amongst the top three visitors in locations NM and MP as the third largest visitor group (NM) and the first largest visitor group (MP) (Figures 5, 6, and 7). All three locations had flowering plant species in the Asteraceae family amongst the most visited plants such as Cats Ear, Yarrow, Daisy Fleabane, and Oxeye Daisy which were also among the most abundant flowering species on average (3.5, 2.3, 3, and 2.5 respectively) (Figures 5, 6, and 7).

The majority of visitors interacted with many plant species and vice versa in the three location networks save for honey bees and bumble bees in NM and bumble bees in MP. Of the

28 bumble bee interaction observations within NM, 85.7% were at Hyssop Hedgenettle plants and of the 29 honey bee interaction observations within NM, 93.1% were at Hyssop Hedgenettle plants as well. Beetles within NM had a similar number of observed interactions (28) but interacted with 7 different plant species with the highest proportion of interactions (50%)

occurring with Yarrow (Table IV and Figure 6). Of the 15 bumble bee interaction observations

within MP, 60% were at Hyssop Hedgenettle while of the 14 Green Sweat Bee interaction

observations 50% were at Cats Ear, the most abundant of the plant species in the MP network

(Table IV and Figure 7).

Table IV. The number of each type of visitor and the number of plants each plant was observed to have been visited during general wandering transects in BW, NM, and MP locations.

BW NM MP Entire Powerline Visitor Plants Plants Plants Plants Type Visitors visited Visitors visited Visitors visited Visitors visited Araneae 0 0 2 2 3 1 5 3 (Spider) Hemiptera 19 5 44 10 37 10 100 14 (Bug) Diptera 3 3 39 9 57 14 99 15 (Fly) Coleoptera 7 3 28 7 7 5 42 9 (Beetle) Lepidopter a (Moth/ 2 1 3 3 6 2 11 4 Butterfly) Ant 4 3 2 2 2 2 8 6 Wasp 0 0 8 5 2 2 10 6 Bumble 1 1 28 4 15 4 44 7 Bee Green 3 3 16 4 14 5 33 7 Sweat Bee Honey Bee 0 0 29 3 1 1 30 4 Medium 10 6 5 3 4 2 19 9 Dark Bee Medium Dark 11 5 46 6 53 10 111 15 Stripes Bee Tiny Dark 16 7 15 8 22 7 53 12 Bee Tiny Dark Stripes 2 2 9 3 10 4 21 6 Bee

Figure 5. Plant-pollinator interaction networks of location BW. Pollinators are shown on the left and plants are shown on the right. The thickness of the pollinator and plant cells represent the total abundance of their interactions and the thickness of the lines connecting cells represents the frequency of interactions.

Figure 6. Plant-pollinator interaction networks of location NM. Pollinators are shown on the left and plants are shown on the right. The thickness of the pollinator and plant cells represent the total abundance of their interactions and the thickness of the lines connecting cells represents the frequency of interactions.

Figure 7. Plant-pollinator interaction networks of location MP. Pollinators are shown on the left and plants are shown on the right. The thickness of the pollinator and plant cells represent the total abundance of their interactions and the thickness of the lines connecting cells represents the frequency of interactions.

The connectance or the realized proportion of possible interactions were of similar values, ranging from 0.24 (BW) to 0.31 (NM) of the three locations (Table V). The connectance for the entire powerline ROW is nearly half (0.46) of possible linkages between the two trophic levels (Table V).

Table V. Metrics representing connectance for BW, NM, MP, and Entire Powerline networks. Location Network Connectance BW 0.24 NM 0.31 MP 0.30 Powerline ROW 0.46

There was no significant difference (t26 = 0.135, p = 0.89) in the number of potential pollinators to native (20.71 ± 17.83, mean ± sd, n = 14) and adventive flowering plant species

19.64 ± 23.75, n = 14). The number of plant visitors of each morphological group and the number of flowering plant species they visited were organized based on the plant’s native status

(Table VI and Figures 8 and 9). There were twice as many flowering plant species in the native plant species, plant-pollinator interaction network (12) than in the adventive plant species, plant- pollinator network (6) (Table VI and Figures 8 and 9). The most visited native plant species was

Hyssop Hedgenettle with 27.9% of the observed interactions and Cats Ear was the most visited adventive plant species with 64.3% of the observed interactions (Table VI and Figures 8 and 9).

Table VI. Summary of number of visitor types observed near the reproductive parts of native vs. adventive flowering plants during wandering transects, along with the number of native vs. adventive plant species that received visits by each the visitor types. Data from all interaction survey sections along the powerline ROW were pooled. Native Adventive # Plants # Plants Visitor Type # Visitors visited # Visitors visited Spider 2 2 3 1 Bug 52 8 48 6 Ant 5 4 3 3 Beetle 35 7 7 2 Fly 52 9 46 5 Lepidoptera 3 3 8 1 Wasp 8 4 2 2 Bumble Bee 38 4 5 2 Green Sweat Bee 7 3 24 3 Honey Bee 29 3 0 NA Medium Dark Bee 11 6 6 1 Medium Dark Striped 22 9 81 4 Bee Tiny Dark Bee 21 6 28 4 Tiny Dark Stripes Bee 5 3 14 2

Figure 8. Plant-pollinator interaction network of native flowering plant species. Pollinators are shown on the left and plants are shown on the right. The thickness of the pollinator and plant cells represent the total abundance of their interactions and the thickness of the lines represents the frequency of interactions. *Pollinators and plants that had less than 5 observed interactions were not included in the figures.

Figure 9. Plant-pollinator interaction network of adventive flowering plant species. Pollinators are shown on the left and plants are shown on the right. The thickness of the pollinator and plant cells represent the total abundance of their interactions and the thickness of the lines represents the frequency of interactions. *Pollinators and plants that had less than 5 observed interactions were not included in the figures.

Focal Plant-pollinator Interaction Surveys

Six flowering plant species, all forbs, were selected for focal surveys: Hyssop

Hedgenettle (Stachys hyssopifolia), Ohio Spiderwort (Tradescantia ohiensis), White False Indigo

(Baptisia lactea), Whorled Loosestrife (Lysimachia quadrifolia), Stiff Yellow Flax (Linum striatum), and Racemed Milkwort (Polygala polygama). Stiff Yellow Flax and Racemed

Milkwort did not receive any visitors. Visitors were first sorted by their order (Figure 10) and subsequently, all visitors belonging to the Hymenoptera order were sorted to their genus (Figure

11). The majority of visitors for Ohio Spiderwort, White False Indigo, and Whorled Loosestrife. were of the Hymenoptera order (Figure 10). Hyssop Hedgenettle, the only forb subject to wandering transects for collection received the most visitors, of which 48% were Hymenoptera and 37.5% were of the true bug (Hemiptera). The majority of the Hemiptera found on Hyssop

Hedgenettle belonged to the Cydnidae family. The primary visitor were bumble bees (Bombus), which made up 14.5% of the visitors. Whorled Loosestrife received the most visitors of the flowering plant species subject to stationary collection followed by Ohio Spiderwort and then

White False Indigo. The most common visitors collected from Whorled Loosestrife were bees from the Lasioglossum genus and flies from the Syrphidae family. Ohio Spiderwort’s primary visitors were of the Lasioglossum genus and the primary visitors for White False Indigo were bees from the Megachile genus.

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50% Hymenoptera

40% Hemiptera Diptera 30% Coleoptera 20%

10%

0% Hyssop Ohio Spiderwort White False Whorled Hedgenettle Indigo Loosestrife

Flower Common Name Figure 10. The percent of the insect orders collected from Hyssop Hedgenettle, Ohio Spiderwort, White False Indigo, and Whorled Loosestrife during wandering and stationary interaction surveys along the powerline ROW.

100% 90%

80% Apis 70% Bombus 60% Ceratina 50% Agapostemon 40% Augochlora 30% Augochlorella Halictus 20% Lasioglossum 10% Megachile 0% Chrysis Hyssop Ohio White False Whorled Hedgenettle Spiderwort Indigo Loosestrife

Flower Common Name

Figure 11. The percent of the specific genera found on Hyssop Hedgenettle, Ohio Spiderwort, White False Indigo, and Whorled Loosestrife belonging to the Hymenoptera order. Genera are sorted by family and are represented by like colors: Apidae are yellow/orange/red, Halictidae are green/blue, Megachilidae are purple and the only genera (Chrysis) which are not a bee but a cuckoo wasp is shown in pink.

Discussion

This survey of flowering plant species on the powerline ROW, cataloged many more species than previous plant surveys of the area, creating a comprehensive baseline of plant species richness and relative abundance for comparison in the years following the implementation of the pollinator habitat enhancement project. Despite differences in the composition, native status and abundances of flowering plant species within the three locations plant-pollinator interaction networks were constructed, their sizes were similar and showed generalist trends for both plants and potential pollinators, with the exception of Bumble bees

(Bombus) and Hyssop Hedgenettle (Stachys hyssopifolia) acting more characteristically of specialists. Focal plant-pollinator interaction surveys revealed the specific genera of bees and orders of non-hymenopteran insects of flowering plant species that we wish to maintain and promote.

This study demonstrated that the majority of the flowering plant species found along the powerline ROW were identified as forbs and in comparison, a small proportion are shrubs and vines. Forbs are excellent sources of pollen and nectar for pollinators and their success in an open area will maintain some of the ideal habitat characteristics associated with insect pollinators

(Holm, 2014). The percentage of forbs in all sections of the powerline ROW are relatively similar and makeup over 90% of the flowering species recorded. Habitats with understories that have been overrun with taller shrubs are characterized as poor habitats for pollinators in comparison with habitats that are open areas where forbs have the opportunity to grow

(Pollinator-Friendly Best Management Practices for Federal Lands, 2015). An overgrown understory would limit the amount of sunlight that could reach forbs, limiting their resources and preventing growth. More sunlight is also beneficial to insect pollinators as they are reliant on the

38 environment to maintain their body temperature. Many insects need to warm their flight muscles before they can become airborne (Heinrich, 1974). Oftentimes, pollinators without adequate access to sunlight would be unable to obtain the nutrients they need from flowers. The powerline

ROW has sufficient sunlight for the success of both forbs and multiple pollination guilds that utilize flight to attain their necessary resources.

The majority of the flowering plant species on the powerline ROW were native, however,

Section A had the greatest percentage of native flowering plant species. In addition to the greater proportion of native plants, Section A was unique from all the other sections of floristic quality surveys as the cataloged plant species had a higher mean coefficient of conservatism and a lower mean wetness coefficient than other sections. The greater coefficient of conservatism indicates that this section is the best representation of a pre-settlement environment and less subject to disturbance of the six surveyed sections (Swink and Wilhelm, 1994). Additionally, the area around Section A, did not border the old pine plantation and therefore had historically experienced less disturbance. The low mean wetness coefficient demonstrated that the most northern section of the powerline ROW was the environment most similar to a wetland (Herman et al., 2001). It is possible that the flowering plant species less tolerant to disturbance were found in Section A because recreational visitors of LAA are less prone to venture off-trail in order to avoid the wetland-like environment.

This section is the only area on the powerline ROW that contained a plant that has been given a conservation status. Baptisia lactea or White False Indigo, has a status of special concern so it does not have legal protection under protected under the Endangered Species Act of the

State of Michigan but is considered vulnerable and if its population continues to decline it may be recommended for threatened or endangered status (Inventory Michigan Natural Features,

1999). Care will be taken with Section A when implementing management of the powerline

ROW to maintain the unique habitat. While herbicide can be effective in treating invasive plants to aid native species combating in competition for resources, herbicide can have direct and indirect negative ecological effects on the treated area (Huang et al., 2005). In Section A, herbicide will be used selectively and will not be seeded as part of the habitat enhancement project as the other five sections will.

The sections south of Rivera Pond: D, E, and F, have the smallest percentage of native plants amongst the six sections. It is possible the difference of Sections D, E, and F from the mean coefficient of conservatism in Section A can be attributed to the historical level of disturbance they were subject to. The recent regular flooding of the last three years subjects the area near Section C and Section D to a fluctuating environment which negatively impacts plant diversity (Chanetone and Facelli, 1991). Habitats under stressful conditions can be more susceptible to the spread of adventive plants because natural competition has been reduced due to the stressed environment (Alpert et al., 2000). The powerline ROW was once the site of agriculture fields, however, there are not records available detailing the relative disturbance of the specific sections measured. It is interesting to note that Section F has the lowest percentage of native plants of all sections, as this was the area at the edge of Kalamazoo College’s property and is next to private property. The nearby disturbance of construction and residential activities on the private property nearby could have affected the flowering plant composition, this is supported by a 2005 study which showed that there are greater percentages of adventive plant species the closer a habitat is to high levels of disturbance (Hansen, 2005).

This study showed that in all sections of the powerline ROW, the majority of flowering plant species present are perennials. Perennials are considered to be intermediaries in the line of

40 succession of different physiognomies after the colonization of disturbed areas (Gleeson &

Tilman, 1990). They are preceded by annuals, and biennials and followed by shrubs and trees

(Fussell and Corbet, 1992). Given that annuals are the primary plant that colonizes a recently disturbed area, the dominance of perennials but the persistence of some annuals such as Spotted

Touch-me-not (Impatients capensis)and Deptford Pinks (Dianthus armeria) found throughout the powerline ROW suggest that this habitat was subject to a relatively stable environment and some disturbance.

Before seeding for the habitat enhancement project can begin, the plant species within the genus Rubus, including Rubus flagellaris found on the powerline ROW need to controlled first.

As there were multiple sections where the abundance of the plant was considered very abundant, it overtook much of the available space on the powerline ROW. To give plants that would be introduced in the seeding aspect of the enhancement project a chance to establish and ultimately act as a resource for pollinators, especially those which do not rely on Rubus species.

In the three networks within the powerline ROW, BW, NM, and MP, flowering plants were visited by many of the same morphological groups of bees and other orders of insect visitors. The visitors were only considered potential pollinators and not pollinators because we did not verify that these visitors were performing effective pollination. Pollen transport data taken from flower visitors give a history of earlier pollination and demonstrate that visitation data cannot accurately predict pollination (Forup and Memmott, 2005). Pollinators benefit from open areas with available sunlight and can be limited to the flying corridors created by the powerline (Wojcik & Buchmann, 2012). As shown by Greenleaf et al. bees’ foraging ranges are directly correlated with body size and given the relatively small study site, it is unsurprising to

41 find the same morphological groups of bees throughout the habitat, especially the larger bees such as bumble bees (2007).

The NM and MP networks had similar values of connectance, where the realized proportion of possible interactions within their respective networks were each a little less than a third. BW network’s connectance is slightly lower and could be in part due to the smaller sampling conducted as less flowering species within the section were in bloom towards the end of the summer. The area had less abundance of flowers able to be pollinated during the second half of plant-pollinator interaction surveys. Dunne et al. (2002) found that and ecosystem’s robustness increases with connectance indicating that NM and MP networks will be slightly more resilient in the event of an ecological disturbance. This indicates and is supported by the floristic quality analysis that the flowering plant species in the BW network are less tolerant of disturbance than other areas of the powerline ROW. The entire powerline ROW will have the greatest robustness indicated by its nearly half of realized possible interactions. This is expected given that all observed flowering plant species and potential pollinators were included in analysis.

While Hemiptera were among the top three potential pollinators in all three interaction networks, they are in general considered much less effective pollinators compared to

Hymenoptera (Forup and Memmott, 2005). The number of pollination services performed by true bug (Hemiptera) visitors was only a fraction of observed interactions despite the high proportion of plant interactions observed of Hemiptera. Similar to Hemiptera, flies (Diptera) which interact with flowers are considered less effective pollinators than bees (of the order

Hymenoptera), but syrphid Diptera (also known as flower flies) are known effective pollinators in agricultural settings (Ssymank et al., 2008). In fact, after the order Hymenoptera, Ssymank et

42 al. considers Diptera to be the most important group of pollinators, and in the wake of declining bee populations Orford et al. pushes for more research into non-syrphip Diptera as effective pollinators after a study showing no difference in the amount of pollen carried in comparison to syrphid Diptera (2008; 2015). Diptera in all three networks were observed interacting with many different flowering plant species, as a collective order, Diptera acted as generalist pollinators.

Within all three networks, bee potential pollinators visit many flowering plant species and most of the flowering species are visited by multiple potential pollinators. This is indicative of a generalist network and is supported by the relatively high proportion of realized interactions

(connectance values). However, there were some groups that displayed more specialist interactions. Bumble bees in both NM and MP networks interacted mostly with Hyssop

Hedgenettle plants and most of the visitors received by Hyssop Hedgenettle plants were bumble bees. Therefore, in order to help protect the bumble bee population on the powerline ROW, care should be taken to keep Hyssop Hedgenettle populations stable during the implementation and maintenance of the habitat enhancement. The maintenance of bumble bee populations is important to consider when midwestern populations have suffered, for example, Bombus Affinis was placed on the endangered species list (U.S. Fish and Wildlife Service, 2020).

Except for Hyssop Hedgenettle, the flowering species with the most visitors for both native and adventive were of the family Asteraceae. This is unsurprising because Cats Ear,

Yarrow, Daisy Fleabane, and Oxeye Daisy were among the most abundant plants on the powerline ROW and because these flowers are characterized by relatively flat inflorescence which provides room for a pollinator to land and gather pollen (Ssymank and Kearns, 2009).

While a diversity of flowering plant species should be seeded for the habitat enhancement

43 project, flowers that have been accessible for a diversity of pollinators should be kept in consideration.

Both Racemed Milkwort and Stiff Yellow Flax are forbs capable of self-pollination and in the case of flaxes, a typical characteristic. Hyssop Hedgenettle was in great abundance and was the only flowering plant species of high coefficient of conservatism value that we could conduct focal wandering transects for. Both the species’ abundance and the different method of collection likely contributed to the richness and diversity of visitors collected from Hyssop

Hedgenettle. The most abundant visitor found on Hyssop Hedgenettle belongs to the Hemiptera

(true bug) order. Multiple of the same true bug, of the family Cynidae were found on a single plant at any given time, and not necessarily on the flower itself but on the leaves and stem as well. It is possible that this visitor uses Hyssop Hedgenettle as a host plant. Other true bugs such as Oncopeltus fasciatus or Large Milkweed Bug use a different forb (Milkweed) as a host plant all over North America (Eaton & Kaufman, 2007). While the species of Cynidae might not be the most efficient pollinator, like Hymenoptera and their specialized physical characteristics to effectively gather pollen Hymenoptera were the next greatest order found on the Hyssop

Hedgenettle, and the genus Bombus was the most abundant. A study conducted at LAA supports this finding when Grimmer found during field surveys at LAA that the most bumble bees on average were found on Hyssop Hedgenettle (2015).

Of the flowering plant species which received visitors in focal interaction surveys, Ohio

Spiderwort and White false Indigo in addition to Hyssop Hedgenettle rely on bumble bees for pollination services. While no literature was found on specific pollinators for Whorled

Loosestrife, McCall and Primack determined that its reproduction is pollinator limited and future studies at LAA should be taken to better understand what organisms provide pollinator services

44 for the species (1985). Ohio Spiderwort is self-incompatible for reproduction and does not have any nectaries, therefore in greater need of a pollinator but simultaneously less attractive to some potential pollinators which only visit flowers for nectar. The primary pollinators for Ohio

Spiderwort are bees of family Halictidae, the genera Bombus, Osmia, and Xylocopa, and syrphid flies from the order Diptera (Holm, 2014). The only potential pollinators observed were of the family Halictidae. Queen and worker bumble bees are the main pollinators for White False

Indigo, but their successful reproduction is at risk due to a number of biotic factors including damage from deer due to browsing, and herbivorous blister beetles (Coleoptera: Lytta sayi) and weevils (Coleoptera: Apion rostrum) (Holm, 2014; Mundahl, 2014). Only one bumble bee, a queen in early summer, was observed on the White False Indigo no beetles were observed either.

However, it is possible that any beetles on the plant were not recorded if they were not near the reproductive parts of the plant and therefore not considered a potential pollinator, but still had the potential to cause damage. White False Indigo should be carefully observed for signs of any of the known threats to the plant in an effort to prevent further decline of the species as it is at risk to do.

Given that three of the four flowering species analyzed in focal plant-pollinator interactions are considered to be reliant on bumble bees for pollination, more work should be done to understand their habits and preferred habitats at LAA. A citizen science project at LAA is scheduled to open to the public in the spring of 2020 will focus on photographing bumble bees and cataloging their location and species, helping to increase our knowledge of bumble bees.

Additionally, a study on the bee nesting conducted in 2019 at LAA will give insight into the nesting habits of bumble bees (arboretum.kzoo.edu/pollinator-habitat-enhancement-project, accessed January 10, 2020).

In the face of pollinator populations declining much in part due to anthropogenic disturbances, this study and the subsequent habitat enhancement will help to address the local pollinators’ and flowering plants’ declines. The measurable success of the enhancement project will give insight into the best management practices for improving the ROW environment. In the following years, while the enhancement project is active, similar studies to this one should be conducted to best measure the impact of various aspects of the project such as plantings, seeding, and applications of any pesticides. In the future, other plant species should be recorded such as sedges, to give a more comprehensive idea of the plant life in the habitat.

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Appendix A. Catalog of all plant species observed flowering along the Powerline ROW during systematic floristic quality surveys conducted between May and August, 2019. Species are sorted by family and listed alphabetically under the family. The common name (or morphospecies), Latin name, family, Coefficient of conservatism (C), Wetness coefficient (W), physiognomy (A-Forb stands for annual forb, B-Forb stands for biennial forb, and P-Forb stands for perennial forb), maximum abundance in the six survey sections, flowering period, and color of the flower are shown as wh: white, pk: pink, or: orange, bl: blue, pu: purple, yw: yellow, li: lilac, red, and gn: green are represented for every recorded flowering plant. Species are shown as native by “N” and adventive by “A”. Coefficients of conservatism values range from 0-10 if a native species, adventive species have a * in place of a value between 0 and 10. The numbers within the “Survey period when flowering” heading represents the week number which flower surveys were conducted (columns for weeks 2 and 3 are greyed out because surveys were not conducted).

Survey period when flowering Survey Section May June July August max. abundance

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Plant family and species Common name/ morphospecies A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Color Native? C W IndexWet Physiogn Avg. Abun. ADOXACEAE Sambucus canadensis Common Elderberry wh N 3 -3 FACW Shrub 0.33 1 1 x x x

APIACEAE B- Daucus carota Queen-annes-lace wh A * 5 UPL 2.67 3 3 3 3 4 x x x x x x x x x Forb A- Torilis japonica Hedge-parsley wh A * 3 FACU 1.83 3 2 2 2 2 x x x Forb APOCYNACEAE P- Apocynum androsaemifolium Spreading Dogbane pk N 3 5 UPL 0.17 1 x x Forb P- Apocynum cannabinum Indian Hemp wh N 3 0 FAC 0.67 4 x x Forb P- Asclepias incarnata Swamp Milkweed pk N 6 -5 OBL 0.67 2 1 1 x x x x x x Forb P- Asclepias tuberosa Butterfly Weed or N 5 5 UPL 0.17 1 x x x x x x x Forb ASTERACEAE P- Achillea millefolium Yarrow (white) wh N 1 3 FACU 2.33 1 2 2 3 3 3 x x x x x x x x x Forb Antennaria spp Pussytoe wh 0.33 2 x B- Arctium minus Common Burdock pu A * 3 FACU 0.17 1 x x Forb

Survey period when flowering Survey Section May June July August max. abundance

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Plant family and species Common name/ morphospecies A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Color Native? C W IndexWet Physiogn Avg. Abun. B- Centaurea maculosa Spotted Knapweed pu A * 5 UPL 1.83 3 2 3 2 1 x x x Forb Chrysanthemum P- Oxeye Daisy wh A * 5 UPL 2.5 3 3 3 3 3 x x x x x x x x x leucanthemum Forb P- Cichorium intybus Chicory bl A * 3 FACU 0.17 1 x Forb P- Cirsium arvense Canada Thistle pu A * 3 FACU 0.17 1 x x x Forb B- Cirsium vulgare Bull Thistle pu A * 3 FACU 0.17 1 x Forb A- Conyza canadensis Horseweed wh N 0 3 FACU 1 1 2 1 2 x x x Forb B- Erigeron annuus Daisy Fleabane wh N 0 3 FACU 3 2 4 3 2 3 4 x x x x x x x x x x x Forb P- Erigeron philadelphicus Philadelphia Fleabane wh N 2 0 FAC 0.5 1 1 1 x x x x Forb P- Erigeron strigosus Lesser Daisy Fleabane wh N 4 3 FACU 2.17 3 3 2 2 3 x x x x x x x x x x Forb P- Eupatorium perfoliatum Boneset wh N 4 -3 FACW 1.5 2 3 2 1 1 x x x x x x Forb P- Euthamia graminifolia Grass-leaved Goldenrod yw N 3 0 FAC 2.67 2 3 3 3 3 2 x x x x Forb P- Eutrochium maculatum Joe-pye Weed pk N 4 -5 OBL 0.67 2 2 x x x x x Forb P- Helianthus giganteus Tall Sunflower yw N 5 -3 FACW 0.33 2 x x x x x x x Forb P- Hieracium aurantiacum Orange Hawkweed or A * 5 UPL 0.5 1 2 x x x x Forb P- Hieracium caespitosum Yellow Hawkweed yw A * 5 UPL 2.5 2 3 3 3 2 2 x x x Forb P- Hieracium gronovii Hairy Hawkweed yw N 5 5 UPL 1.83 3 3 2 2 1 x x x x x x Forb Hieracium spp. *Smooth Hawkweed yw 2.17 2 3 3 2 2 1 x x x x x x P- Hypochaeris radicata Cats Ear yw A * 3 FACU 3.5 3 3 4 4 4 3 x x x x x x x x x x x x x Forb P- Krigia biflora Cynthia yw N 5 3 FACU 1 3 3 x x x x Forb

Survey period when flowering Survey Section May June July August max. abundance

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Plant family and species Common name/ morphospecies A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Color Native? C W IndexWet Physiogn Avg. Abun. A- Krigia virginica Dwarf Dandelion yw N 4 5 UPL 0.83 2 3 x x Forb B- Lactuca biennis Tall Blue Lettuce wh N 2 0 FAC 1.67 2 3 2 2 1 x x x x Forb B- Lactuca Canadensis Wild Lettuce yw N 2 3 FACU 1.5 1 1 2 3 2 x x x x x x Forb A- Lapsana communis Nipplewort yw A * 3 FACU 0.5 1 1 1 x x x x x Forb P- Rudbeckia hirta Black-eyed Susan yw N 1 3 FACU 1.67 2 2 3 3 x x x x x x x x x x Forb P- Senecio aureus Golden Ragwort yw N 5 -3 FAWC 0.5 2 1 x x Forb P- Solidago rugosa Rough-leaved Goldenrod yw N 3 0 FAC 0.67 2 2 x x x Forb Solidago spp. Goldenrod yw 2.67 3 3 3 3 3 1 x x x x x A- Sonchus asper Spiny-leaved Sow Thistle yw A * 3 FACU 0.17 1 x x Forb P- Taraxacum officinale Common Dandelion yw A * 3 FACU 1.17 1 2 2 2 x x Forb - *False Wild Lettuce yw 2.5 3 3 3 3 3 x x x x x x x x x x - *Most Regular Cats Ear yw 1.83 1 3 3 2 2 x x x x - *Small Dandelion yw 1.17 2 3 1 1 0 x x x x x - *Purple Thistle 3 pu 0.17 1 x

BALSAMINACEAE A- Impatiens capensis Spotted Touch-me-not or N 2 -3 FACW 2 2 2 2 2 4 x x x x x x x x Forb BRASSICACEAE A- Berteroa incana Hoary Alyssum wh A * 5 UPL 0.17 1 x Forb P- Hesperis matronalis Dames Rocket wh A * 3 FACU 0.17 1 x Forb CAMPANULACEAE

Survey period when flowering Survey Section May June July August max. abundance

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Plant family and species Common name/ morphospecies A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Color Native? C W IndexWet Physiogn Avg. Abun. A- Lobelia inflata Indian Tobacco li N 0 3 FACU 1 1 1 1 1 2 x x x x x x x Forb CARYOPHYLLACEAE P- Cerastium fontanum Mouse-ear Chickweed wh A * 3 FACU 0.83 1 2 2 x x x Forb A- Dianthus armeria Deptford Pink pk A * 5 UPL 2.33 3 3 3 3 2 x x x x x x x x x x Forb A- Silene pratensis White Campion wh A * 5 UPL 1.33 2 2 2 2 x x x x x x x x x x x Forb COMMELINACEAE P- Tradescantia ohiensis Ohio Spiderwort pu N 5 3 FACU 1 2 2 2 x x x x x x x Forb CONVALLARIACEAE P- Smilacina racemosa False Solomons-seal wh N 5 3 FACU 0.83 2 3 x Forb EUPHORBIACEAE P- Euphorbia corollata Flowering Spurge wh N 4 5 UPL 2.17 2 3 3 3 2 x x x x x x x x x x Forb FABACEAE P- Baptisia lactea White False Indigo wh N 9 3 FACU 0.33 2 x x x Forb P- Desmodium marilandicum *Small-leaved Tick-trefoil pk N 7 5 UPL 0.83 1 3 1 x x x x Forb P- Desmodium obtusum *Stiff Tick-trefoil pk N 9 5 UPL 0.33 2 x Forb P- Hylodesmum glutinosum *Clustered-leaved Tick-trefoil pk N 5 5 UPL 1.17 1 2 2 2 x x x x Forb P- Hylodesmum nudiflorum Naked Tick-trefoil pk N 7 5 UPL 0.5 1 1 1 x x Forb P- Lespedeza hirta Hairy Bush-clover wh N 7 5 UPL 0.5 2 1 x x x x Forb P- Trifolium pratense Red Clover pu A * 3 FACU 0.5 1 2 x x x x x x x Forb P- Trifolium repens White Clover wh A * 3 FACU 2.5 3 3 3 2 2 2 x x x x x x x x x x x Forb

Survey period when flowering Survey Section May June July August max. abundance

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Plant family and species Common name/ morphospecies A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Color Native? C W IndexWet Physiogn Avg. Abun. P- Vicia cracca Tufted Vetch pu A * 5 UPL 0.17 1 x Vine HYPERICACEAE P- Hypericum perforatum Common St Johnswort yw A * 5 UPL 2.17 2 2 3 3 3 x x x x x x x x x Forb P- Hypericum punctatum Spotted St Johnswort yw N 4 0 FAC 3 3 3 3 3 3 3 x x x x x x x x x Forb LAMIACEAE P- Lycopus uniflorus Northern Bungleweed wh N 2 -5 OBL 0.17 1 x Forb P- Mentha arvensis Wild Mint li N 3 -3 FACW 0.33 2 x x x x x x x x Forb P- Monarda fistulosa Bee Balm pu N 2 3 FACU 0.17 1 x x x Forb P- Prunella vulgaris Heal-all pu N 0 0 FAC 1.5 2 3 1 1 2 x x x x x x x x x x Forb P- Scutellaria galericulata Marsh Skullcap pu N 5 -5 OBL 0.33 1 1 x x Forb P- Stachys hyssopifolia Hyssop Hedgenettle li N 10 -3 FACW 2.83 3 4 4 3 3 x x x x x x x x x Forb LINACEAE P- Linum striatum Stiff Yellow Flax yw N 10 -3 FACW 1.17 1 3 2 1 x x x x x Forb MYRSINACEAE P- Lysimachia lanceolata Lance-leaved Loosestrife yw N 9 0 FAC 0.33 1 1 x x x Forb P- Lysimachia quadrifolia Whorled Loosestrife yw N 8 3 FACU 2.83 5 4 4 4 x x x x x x Forb ONAGRACEAE P- Circaea canadensis Enchanters Nightshade wh N 2 3 FACU 2.17 2 2 3 3 3 x x x x x x x x x Forb P- Epilobium ciliatum Willow-herb pk N 3 -3 FACW 0.83 1 2 2 x x x Forb B- Oenothera biennis Common Evening-primrose yw N 2 3 FACU 2 3 3 2 2 2 x x x x x x x x x Forb

Survey period when flowering Survey Section May June July August max. abundance

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Plant family and species Common name/ morphospecies A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Color Native? C W IndexWet Physiogn Avg. Abun. OXALIDACEAE P- Oxalis stricta Yellow Wood Sorrel yw N 0 3 FACU 0.83 1 2 2 x x x x x x x x Forb PHRYMACEAE P- Mimulus ringens Monkey Flower pu N 5 -5 OBL 0.17 1 x x x x x Forb PHYTOLACCACEAE P- Phytolacca americana Pokeweed wh N 2 3 FACU 0.33 1 1 x x x Forb PLANTAGINACEAE P- Plantago lanceolata English Plantain wh A * 3 FACU 1.83 2 2 3 2 2 x x x x x x x x x x Forb A- Veronica arvensis Corn Speedwell bl A * 3 FACU 0.67 2 2 x x Forb P- Veronica officinalis Common Speedwell li A * 3 FACU 2.67 3 3 2 3 3 2 x x Forb POLYGALACEAE B- Polygala polygama Racemed Milkwort pu N 9 3 FACU 0.67 2 2 x x x Forb A- Polygala sanguinea Field Milkwort pu N 4 3 FACU 0.17 1 x x Forb POLYGONACEAE P- Persicaria hydropiperoides Mild Water-pepper wh N 5 -5 OBL 1.17 2 2 2 1 x x x x x x Forb A- Persicaria maculosa Ladys Thumb pk A * 0 FAC 0.33 2 x x x Forb A- Persicaria pensylvanica Pinkweed pk N 0 -3 FACW 1.83 2 2 2 2 3 x x x x Forb A- Persicaria sagittata Arrow-leaved Tear-thumb pk N 5 -5 OBL 0.67 3 1 x x x x x Vine P- Persicaria virginiana Jumpseed wh N 4 0 FAC 0.67 1 1 2 x x x x Forb P- Rumex acetosella Field Sorrel red A * 3 FACU 1.67 3 2 2 3 x x x x x Forb

Survey period when flowering Survey Section May June July August max. abundance

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Plant family and species Common name/ morphospecies A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Color Native? C W IndexWet Physiogn Avg. Abun. P- Rumex crispus Curled Dock gn A * 0 FAC 0.33 2 x x Forb P- Rumex obtusifolius Bitter Dock gn A * 0 FAC 1 1 1 1 3 x x x x Forb RANUNCULACEAE P- Anemone virginiana Thimbleweed wh N 3 3 FACU 0.33 1 1 x x x x Forb A- Ranunculus pensylvanicus Bristly Crowfoot yw N 6 -5 OBL 0.33 1 1 x x x Forb RHAMNACEAE Rhamnus alnus Glossy Buckthorn gn A * 0 FAC Shrub 0.33 1 1 x x x

ROSACEAE P- Agrimonia gryposepala Tall Agrimony yw N 2 3 FACU 1 2 1 2 1 x x x x Forb P- Fragaria virginiana Wild Strawberry wh N 2 3 FACU 0.33 2 x Forb P- Geum aleppicum Yellow Avens yw N 3 0 FAC 1 1 2 3 x x x x x x Forb P- Geum canadense White Avens wh N 1 0 FAC 1.83 1 2 3 2 3 x x x x x x Forb A- Potentilla norvegica Rough Cinquefoil yw N 0 0 FAC 0.67 1 1 1 1 x x x x Forb P- Potentilla recta Rough-fruited Cinquefoil yw A * 5 UPL 0.33 1 1 x x x Forb P- Potentilla simplex Common Cinquefoil yw N 2 3 FACU 3 3 3 3 2 4 3 x x x x Forb W- Rosa multiflora Multiflora Rose wh A * 3 FACU 0.17 1 x Vine Rosa palustris Swamp Rose pk N 4 3 FACU Shrub 0.17 1 x Rubus flagellaris Northern Dewberry wh N 1 3 FACU Shrub 4.33 4 5 5 5 4 3 x x x x x x Rubus spp Rubus spp wh 2.83 3 4 3 3 4 x x x Spiraea alba Meadow Sweet wh N 4 -3 FACW Shrub 0.5 1 1 1 x x x x x

Survey period when flowering Survey Section May June July August max. abundance

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Plant family and species Common name/ morphospecies A B C D E F 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Color Native? C W IndexWet Physiogn Avg. Abun. RUBIACEAE P- Galium triflorum Fragrant Bedstraw wh N 4 3 FACU 0.17 1 x x Forb P- Mitchella repens Partridgeberry wh N 5 3 FACU 0.17 1 x Forb SANTALACEAE P- Comandra umbellata Bastard Toadflax wh N 5 3 FACU 0.17 1 x Forb SCROPHULARIACEAE B- Verbascum thapsus Common Mullein yw A * 5 UPL 0.83 1 2 1 1 x x x x Forb SOLANACEAE P- Solanum carolinense Horse Nettle wh A * 3 FACU 0.17 1 x x x x Forb W- Solanum dulcamara Bittersweet Nightshade pu A * 0 FAC 0.33 1 1 x x Vine VERBENACEAE P- Verbena hastata Blue Vervain pu N 4 -3 FACW 0.5 2 1 x x x x x x x Forb P- Verbena urticifolia White Vervain wh N 4 0 FAC 0.17 1 x x Forb VIOLACEAE P- Viola blanda Sweet White Violet wh N 5 -3 FACW 0.33 2 x Forb P- Viola sagittata Arrow-leaved Violet pu N 8 0 FACU 1.33 3 3 2 x Forb

Appendix B. Plant-pollinator interaction network of flowering plant species along entirety of Powerline ROW. Pollinators are shown on the left and plants are shown on the right. The thickness of the pollinator and plant cells represent the total abundance of their interactions and the thickness of the lines represents the frequency of interactions. *Pollinators and plants that had less than 5 observed interactions were not included in the figures.