Ecological Implications for the Management of Dog-Strangling Vine (Vincetoxicum Rossicum)

Experimental Eradication of an Invasive Exotic Vine in the Trent University Nature Areas:

Completed By: Kieran Pinder

Course: Community-based Research Project (TCCBE) Supervisor: Dr. Tom Whillans Due: December 16, 2011

1. Abstract

The Nature Areas Committee at Trent University oversees the natural heritage of the campus, and is committed to including students in community-based research projects which involve scientific experimental design projects. The experiment described here on out deals with restoration management of natural areas on the campus of Trent University and particularly focuses on introduced, non-native plants as a degrading force in these natural areas. Within the context of this report for the Trent Nature Areas Committee, an accredited course was established with the Trent Centre for Community-Based Education (TCCBE) that initiates the discussion on an emergent issue within many southern Ontario natural areas. This course focuses on the biology and ecological impacts of a plant which has escaped cultivation in North America, originally introduced from Eastern Europe and named the Dog- strangling vine (Vicetoxicum rossicum). This vine has found habitat in in areas of concern within the Trent NA. It is highly invasive as a perennial herbaceous plant, and has consequently infiltrated three particularly evident sites in the Trent NA, and therefore has potential to invade and dominate both the areas where it currently resides, as well as adjacent ecosystems of which are particularly vulnerable to widespread infestation in the future. Within these parameters of the V. rossicum species, this particular report will outline the implemented management techniques for controlling the spread of this plant. The program was initiated by the Trent Nature Areas Committee, and facilitated by the grounds-keeping crew of the Physical Resources department. It is aimed at discovering an effective chemical treatment method for managing V. rossicum. Outlined in this report will be the history of this particular plant invasion in eastern North America, detailed consequence of its introduction into Ontario nature areas, and a solution for managing its population spread. Finally, it will recommend and propose ideas for the future eradication of V. rossicum on the TNA, and detail the monitored ecological responses therein.

2. Introduction

2.1 Assessment and Management of Plant Invasions

People who have a keen commitment to environmental issues such as land managers, naturalists, and ecologists, have noticed the rapid infiltration of invasive plants into non-native regions around the world (Sheeley and Raynal 1996; McKague and Cappuccino 2005; Matilla and Otis 2003; Lawlor 2002; Lawlor 2000; Hanrahan 2006; Ladd and Cappuccino 2005; DiTommaso 2005; DiTommaso et al 2005; DiTomasso and Losey 2003; Catling and Mitrow 2005; Casagrande and Dacey, 2007; Cappuccino et al, 2002; Cappuccino, 2004; Abouziena et al 2009). Increased anthropogenic globalization and transport of plants, coupled with activities that cause environmental degradation have combined to cause a rapid increase of non-native plants into historically native ecosystems (Cappuccino et al. 2002; Catling and Mitrow 2005; DiTommaso 2005). These plants typically originate on separate continents where competition in their native ranges limits their success in the ecosystems (Lauvanger and Borgen 1998). However, upon introduction to other regions for horticultural or agricultural purposes, they eventually escape cultivation by seed dispersal, and establish in ecosystems where competition is usually much less than in their native ranges (Lauvanger and Borgen 1998). The term invasive refers to the spread, establishment, and dominance of these plants in ecosystems. The term exotic, that usually follows the term invasive, refers to the alien nature of the plant and its non-native attributes within the environment. Hence, the term invasive exotic plant refers to a plant that originates from another region of the world and has spread its population voraciously in a region that it isn’t inherently native. As the earth’s landscapes and ecosystems become increasingly disturbed by anthropogenic resource exploitation and mass transportation of biological materials cross-continents, many life forms are adapting at an alarmingly fast rate and capitalizing on opportunities to colonize non-native disturbed areas (Catling and Mitrow 2005). Inherently associated with their existence is a strong competitive force that tends to out-compete native plants, thereby displacing food and resources for native species of wildlife. Additionally, plants can cause significant problems for the economy, which include agricultural, fishing, and forestry industries (Havinga 2000). It has been stated by Pimental (1999) that the costs associated with control of only two plants, purple loosestrife (Lythrum salicaria) and melaleuca (melaleuca quinquenervia), have been estimated at $48 million. Because of these reasons, global efforts of assessment and management of invasive exotic plant populations is nearing the critical peak of importance. Luken and Thieret (1997) explain why plant invasions have become so increasingly rampant. They state,

“While invasion and range of expansion were indeed a part of the biological history of earth before humans, the rate and scale at which invasions occurred was not similar to that resulting from human activity. The human-caused breakdown of barriers to species dispersal was a global phenomenon and because this had ramifications at all levels 3 of biological invasion from the populations and genes to ecosystems and landscapes, invasions should be recognized as one of the major global environmental issues of our time.”

Such an important conservation issue is, unavoidably, requires an extremely complex assemblage of multi-faceted efforts (Havinga 2000). These efforts are first and foremost geared toward prevention of initial and successive plant invasions. These important frontline actions require radical changes in human perception regarding land use practices and transport of exotic plant materials. In situations where exotic plants have already invaded an area, direct and immediate control is necessary but may present an undertaking that is beyond the realm of available resources, depending on the extent to which the plant has established. The most cost- and time-effective strategies should be researched and implemented in any scenario, to provide an efficient management regime for the restoration of a natural area. Entwined within this strategy can be many complications, which lead to controversy over the seemingly contradictive use of certain control methods to restore natural ecosystem integrity, such herbicidal application.

The control of invasive exotic plant populations requires the establishment of a detailed strategic framework that incorporates the interests of individuals and institutions with the preservation of natural heritage. Analyzing and researching situations, ordering objectives, developing partnerships, and creating goals for control can all contribute to a collective discussion about proactive steps to take in dealing with problematic and challenging plant invasion scenarios. This discussion should integrate the baseline availability and commitment to the use of available resources. The following strategic plan was adapted from Havinga (2000) and includes eight key strategies. The first four are discussed in this chapter and the final four are discussed in the conclusion chapter. They read as such:

1. Prevention of further introductions In this situation, it is obvious that prevention of invasive plants is the most effective long-term solution for ecological sustainability. Often introduced through the escape from horticultural or agricultural domestication, these plants typically establish and dominate their populations in naturalized environments that have been previously degraded by direct anthropogenic or non- anthropogenic natural processes. As a consequence, the actions of preventing invasions should indeed, focus on minimizing the introductions combined with enacting sustainable environmental practices in order to preserve natural heritage of ecosystems. Some specific actions include:  Prevent the use and transport of invasive exotic plant materials in landscaping or horticultural settings near natural areas

 Develop early warning systems which describe the potential of certain environments to be infiltrated by invasive plants  Monitor and manage already-present invasive plants by educating individuals closely associated with managing natural areas  Promote the cultivation and naturalization of appropriately-sourced native plants for landscaping and natural areas restoration  Promote the conservation of native ecosystem integrity by minimizing disturbance in natural areas

2. Development of strategies for managing target plant species In its current state, there is a growing necessity for research regarding invasive plant management in southern Ontario. However, objective research can be documented and described regarding plant invasion scenarios that have occurred in locations that are similar to the environments of southern Ontario. Some specific actions include:  Research and educate the targeted community on priority invasive plants of the region, with an overview of potential guidelines for management regimes  Promote the use of the Integrated Pest Management strategy that limits the use of herbicides and instead relies on mechanical methods of control, if feasible

3. Identify priority areas of concern for control and management The challenging task of managing invasive species can seem daunting, but focusing on areas that are of priority interest can help narrow the scope towards concentrating on significant causes of the situation. Addressing the most-needed areas for management regime is essential to eradicating current invasions and prohibiting further invasions. Some specific actions include:  Surveying of all natural areas potentially at risk  Identifying those sites which pose future risks to adjacent ecosystems  Recording and documenting the location of these sites

4. Conduct experimental field research on efficacy of control methods As stated earlier, few studies on invasive plant management have been conducted in southern Ontario, so primary research with community-based resource management principles can effectively educate the interested individuals or institution on future endeavors. Some specific actions include:

 Firstly, research the literature and create a bibliography of current studies, done by accredited institutions and community organizations, on control of targeted invasive plants  Secondly, establish scientifically-valid field research plots in the priority areas, test appropriate test control methods, and document results in a report for circulation among interested parties  Include best monitoring techniques, including environmental assessment, species biological and historical information, species distribution and density, and control methods used.  Include an analysis of the historical pre-invasion state, reasons for invasion, displacement of the native plant community, long-term impacts proceeding control, implications for regional environmental changes.  Additionally, a cost-benefit analysis should be included that weighs the pros and cons of managing, versus not managing the invasive plant populations. The researcher would assess the damage that current invasions pose to ecosystems, versus the damage that management programs would inflict. Furthermore, the benefits and costs of reintroducing native plants into the disturbed area post-control should be assessed.

2.2 Community-Based Education and Invasive Plant Management in the Trent Nature Areas

The Trent Nature Areas (TNA) encompass all designated natural landscapes within the Trent University grounds and includes forest and meadow lands which combine for 90 acres of the 175 (52%) acres of campus lands (T.N.A. 1997). They present vital opportunities for visitors to experience the natural world and in so doing, represent the University’s commitment to preserving and honouring the natural features found in the landscapes of this northern Peterborough area. The TNA affords visitors the chance to view wildlife, study nature, and enjoy many recreational activities like hiking, bird watching and cross-country skiing. In this right, the TNA are appreciated for the marvelous aesthetic and natural qualities. Part of the TNA’s mandate is to promote land stewardship through the provision of post-secondary learning opportunities in conducting field research and presenting the collected data in written report and oral presentation formats. Hence, this report will document the procedures and methods involved with the experimental eradication the invasive exotic plant Dog-strangling vine (Vincetoxicum rossicum). The recommendations subsection of the Executive Summary contained in the Trent Grounds Management

Plan (2005) advocates for, “The minimization of the presence of invasive exotic plants” as the second most important objective. The collective goals of an invasive plant management strategy for Trent University includes:

 Maintaining healthy ecosystems, native biodiversity, and natural heritage  Reducing economic and recreational impacts of invasive exotic plants  Advancing institutional knowledge and attitudes toward invasive exotic plants  Providing resources for land managers of the TNA to eradicate invasive plants

The ways in which this invasive plant can alter a landscape can be easily understood in a simple framework, provided by scholars in past articles. Vitousek (1990) describes the potential of plant species in altering ecosystem processes. The most prominent factors that classify the plant as invasive include those factors that,

1. Alter the disturbance regimen 2. Alter the trophic structure of an area 3. Alter the rate of accumulation or supply of resources

These factors all contribute to the core concept of this report, and the course in its entirety, which maintains that practical research is needed for the development of a regime which protects the natural heritage of the TNA. Next to be described in this report is the biological traits of this invasive plant.

2.3 Vincetoxicum Rossicum: Description of Biology and Life Stages

V. rossicum is a perennial herbaceous vine (Cappuccino, 2004; Cappuccino et al, 2002; DiTomasso and Losey 2003; Kleopow 1990; Lawlor 2002) that spreads voraciously through soil with its roots, twines and smothers relentlessly through the above-ground environment, and reproduces extensively through the production of large amounts of wind-dispersed seed (Cappuccino et al, 2002; Ladd and Cappuccino 2005).The root system of this plant is extensive within large exclusive thickets which physically and chemically inhibit other vegetation contained within the ecosystem (Cappuccino, 2004; Mogg et al 2007), thereby allowing many more shoots to emerge for increased growth and reproduction mechanisms . The stems sense the physical environment impeccably, climbing up trees to increase photosynthesis, spreading over brush piles, smothering native vegetation, and even twining upwards with multiple other V. rossicum stems to create upright assemblages (Di Tommaso et al 2005; Catling and Mitrow 2005,

7 personal observation). The leaves of this vine are arranged oppositely, and have pointed tips with an ovate form with sizes that vary between 8 to 12 cm in length and 3 to 7 cm in width, depending on the ecosystem and life stage (Ladd and Cappuccino 2005). The flowers are small and shaped much like a starfish with colouring of reddish brown, and sizes of 1 to 2 cm in width (DiTommaso 2005). The seeds are shaped as slim pods which culminate into a point and range from 5 to 7 cm long and 5 to 7 mm wide. The dispersal method of seeds contained within the pods is strictly a wind-dispersed design (Lawlor 2002). The downy hairs attached to the small, lightweight seeds provide an ability to parachute on wind currents and travel large distances before contact with a soil surface for initiation of germination processes (Ladd and Cappuccino 2005).

Similar to other perennials it competes with, V. rossicum flushes its shoots and leaves from its root systems in early spring (April and May), flowers during early to mid summer (June and July), and self pollinates during late summer to early autumn (August to September) to create the seed pods which spread by wind during the remaining months before winter dormancy (Ladd and Cappuccino 2005). Although seed dispersal is the main source of production, V. rossicum also spreads by tenacious suckering from root crown to create newly emergent shoots and hence, constantly create more growth and reproductive value per individual plant clump (DiTommaso 2005).

Table 1. Basic Information Common Dog-strangling Names: vine, pale swallow-wort Scientific Vincetoxicum Name: rossicum Kingdom: Plantae Phylum Magnoliophyta Class Magnoliopsida Order Gentianales Family Asclepiadaceae Genus Cynanchum Species Rossicum Habitat Open meadows Preferred and forest understories

2.4 Habitat Preferences

V. rossicum prefers habitats situated on well-drained upland areas such as drumlin tops and slopes, and inhabits a wide range of light environments ranging from shaded to open areas (Cappuccino et al, 2002; Casagrande and Dacey, 2007; Sheeley and Raynal 1996). Therefore, it is highly tolerant of many ecotypes which makes for a tenacious vegetative presence wherever it is established. The most typical habitat classifications of V. rossicum include old-fields, natural and planted woodlands, and brushy meadows (Sheeley and Raynal 1996). Areas that are affected by anthropogenic disturbance such as abandoned agricultural lands or planted forests, are both habitats for present thickets already established, as well as transportation and dispersal corridors for new seeds (Ladd and Cappuccino 2005). These areas include but are not limited to disturbed slopes, transportation pathways, fallow agricultural fields, and invasive tree plantations (Sheeley and Raynal 1996). This vine’s extensive range of habitat occupancy is impressive, but provides serious threats to many ecosystems upon introduction. The authors of a 2007 report by Toronto Region Conservation Authority (TRCA 2007) on V. rossicum stated that, “In the opinion of the authors of this report, V. rossicum is the single most virulent invasive vascular plant species in Ontario.” They then state that the plant made the top twenty list of prioritized invasive plants in all of Canada (Catling & Mitrow, 2005). The photos below depict mature infestations of V. rossicum in two different ecosystems and are adapted from TRCA (2007).

The Urban Forest Associates of Toronto state in their report (UFORA 2011) that V. rossicum is classified as an, “aggressive invasive exotic species that can dominate a site to exclude all other species and remain dominant on the site indefinitely.” They include a table of important invasive exotic plants in Ontario

forests which I have adapted to include herbaceous old-field and forest understory perennials, shown in Table 2.

Table 2. Invasive Exotic Perennials of Ontario Scientific Name Common Name Effect on Natural Area Aegopodium podagraria Goutweed dominates forest understorey Alliaria petiolata Garlic mustard dominates forest herb layer Cirsium arvense Canada thistle dominates meadows, prairies, forest edges Coronilla varia Crown vetch dominates disturbed meadows Cynanchum nigrum Black swallow- wort dominates meadows & forest understorey Cynanchum rossicum Pale swallow- wort dominates meadows & forest understorey Hesperis matronalis Dames rocket dominates open forest understorey & meadows

2.5 History of Introduction and Invasive-Range Ecological Threat

Native to eastern Europe (Figure 1), this plant was introduced into North America for ornamental purposes (DiTommaso 2005; Ernst 2005), and was first observed invading natural ecosystems in Nassau and Monroe counties of New York State in the year 1897 (Cappuccino et al, 2002). Since then, it has had a documented presence in Indiana, Michigan, New Hampshire, Massachusetts, Pennsylvania, New Jersey, and more recently, within Ontario ecosystems (Figure 2; Cappuccino et al. 2002). This plant does not demonstrate qualities of extreme invasiveness in its native home range of Ukraine and European Russia (Kleopow 1990). However, upon introduction into North America, it has gained an ecological foothold, mainly because the plant competition, pathogens, and herbivory that it experiences in Europe simply does not exist on the North American continent (Sheeley and Raynal 1996; Lauvanger and Borgen 1998). This plant does not provide valuable resources to native wildlife of the Great Lakes Lower Basin (Casagrande and Dacey, 2007; DiTomasso and Losey 2003; Hanrahan 2006) and actually presents a biological threat to monarch butterflies (Danaus plexippus) which lay eggs on the plant, presuming it is a native Asclepidaceae, but unfortunately the hatched larvae are poisoned after herbivory of tissues (Casagrande and Dacey, 2007; DiTomasso and Losey 2003). Furthermore, it excretes allelopathic chemicals into to the soil matrix (Cappuccino 2004). Mogg et al (2007) demonstrated that the rhizomes of V. rossicum contain potent antibiotic chemicals as the product of a highly allelopathic metabolite. Therefore, this plant degrades native mutualistic relationships contained within the soil, and inhibits microorganisms from cohabitating in the soil ecosystem. Hence, it can invade an area and cripple the native ecological integrity

10 contained within, thereby creating highly suitable environments for its growth and reproduction especially under low-competition landscapes.

Figure 1: Native range of V. rossicum in eastern Ukraine, western Russia (TRCA 2007)

Figure 2 The distribution of V. rossicum in Ontario (Source: DiTommaso et al. 2005)

Additionally, the vine spreads voraciously due to its wind-dispersed seed design. For example, some old- field habitats - including the Lady Eaton Drumlin site evaluated in this report – that naturally contain native goldenrods, milk thistles, milkweeds, and grasses, have become invaded by or outright replaced by V. rossicum. Therefore, the successional processes toward native climactic states have been strongly altered. Studies have been conducted on the wildlife interaction impacts of V. rossicum invasions and by and large, have demonstrated that avian and insect populations dramatically decline as a result of native plant replacement with this vine (Ernst 2005; Hanrahan 2006).

2.6 Research and Management Protocol

Many conservation authorities in Ontario share the concern of the T.R.C.A. and are enacting research and management protocols geared toward assessing the risks of V. rossicum invasions and consequently managing the risk posed to the regional resources. In addition, natural areas managers of academic institution properties have published articles for internal use, such as that of the Trent Grounds Management Plan (Trent University 1997), that document the presence of invasive plants in proportion to native plants on the entire campus property. Depicted in Table 3 are six recommendations published in the report that relate most heavily to the invasive situation of V. rossicum.

Table 3. Description of Executive Recommendations: Implement a policy to exclude invasive exotic plant Implement a control program in zones exceeding material from all future landscaping, especially this 5% maximum - refer to recent those designated as “especially troublesome” Aim to maintain no more than 5% invasive exotic Research in effective control measure for invasive trees and shrubs in any of the six designated zones plants Begin control program in Founders Walk Implement a policy to ban all further planting of plantation, using 50% Roundup (glyphosate) Norway Maple (Acer platanoides) on campus, and painted on cut stumps - document results consider removal of existing trees

Adapted from T.N.A. (2011)

Within the section of the report that details the proposed actions for eradicating invasive plants, the recommendations shown in Table 3 include both short-term management of current invasive species populations and long-term guidelines that protect against future invasions. At the time of the this report however, V. rossicum was likely not nearly as established as in 2011 and therefore, discussion of an eradication regime for this species was absent from the report. Therefore, emergent peer-reviewed and public research that details the efficacy of eradication techniques for this plant was assembled and used to

12 construct an invasive plant management research project within invaded areas of the Trent University Nature Areas.

3. Methods

3.1 Experimental Designs for Invasive Plant Research and Management

Collecting viable and trustworthy data in invasive plant science is especially important to the validity and congruency of the information, since field-based research is difficult but necessary in many situations. When examining the designs of previous experiments on V. rossicum, it is much more likely that ecological fieldwork will yield variables that give direct results of ecosystem-level effects derived from a management experiment. However, as opposed to controlled laboratory plant growth studies, ecological fieldwork presents a host of variables including unstable weather patterns and stochastic ecosystem-level activities. In order to narrow the margin of error, this report has mimicked proper scientific data collection protocol from peer-reviewed journals regarding the proper techniques and principles in the collection of data for V. rossicum. By analyzing these scientific reports, which have been conducted mostly in northeastern United States, and relating it to local or regional public reports in southern Ontario (Havinga 2000; TRCA 2007; UFORA 2011) this report has gained a local, regional, and continental outlook on the prospects of this issue. The scientific research has provided historical, detailed descriptions of methods and materials used in the study of this invasive plant, and the public research has provided a current outlook on the prospects of its spread in relation to the landholders affected by its presence.

A solid plan for sampling design and analysis would prove to be highly relevant to scientific studies of plant invasion management. I met with Tom Whillans and Marjorie McDonald in May 2011 to gather the information necessary to create my research question. With the generous assistance and guidance of William Forsyth, Grounds Manager, I conducted extensive preliminary surveying of the 90 acres of Trent Nature Areas, for the presence of sites invaded by V. rossicum. The initial conception of the problem became much clearer as I examined the extents of this plant’s invasion within the Trent University Nature Areas. Three particular sites were invaded by the plant and deemed necessary to study. However, one was designated as off-limits due to the potential for vandalism. Therefore, the two sites were selected to implement the same control regime, and compare efficacy between the two. Following official meetings and registration in the course, I realized in early June that this management project would have to start immediately since most effective treatment of V. rossicum was shown by studies to occur in May and June. I refined the question by assessing the purpose of this report. Mainly, this report would be a community-based report for internal use at Trent University, and those interested in reading the results would appreciate the detailing of practical, applicable methods used in the research. In other words, I

13 chose chemical treatment methods for this plant because the literature demonstrated that foliar herbicide application can be the most effective and efficient treatment method for natural areas managers, as opposed to mechanical control methods that include cutting stems, pulling whole plants out of the ground, smothering with black plastic, and mulching the area of study. Therefore, the research question asks, “Which herbicidal treatments on dog-strangling vine (V. rossicum) would be most effective for an invasive exotic plant management program?”

I designed my experiment to include three replicates of each control measure at each site, with three plots of glyphosate treatment (Round Up), acid treatment (Eco Clear), and no-treatment at the Lady Eaton Drumlin (LED) and Morton Trail Drumlin (MTD) sites. Therefore, the replication of each control method at each site will ensure validity and reduce errors of interpretation. Furthermore, the significance of the statistics will be enhanced and stronger relations can be concluded to occur. Three plots per control treatment was the maximum amount of plots for the given space of invasion at each site.

Within my monitoring regime, I kept sampling congruency within the allocated dates to ensure all observations were conducted at the exact same time, location, and condition. The regime consisted of visual documentation and numerical percentage of plant tissue damage, noticed at biweekly intervals as to provide four monitoring dates. The location of plots was semi-random because plot locations were chosen randomly within the site, but were repositioned to be properly spaced, to avoid over-spray and contamination of adjacent plots.

I highlighted the importance of control plots in this study as a key objective because comparison with them would prove the existence of some or no effect in the other experimental plots. I designed the control plots as exact replicates to the experimental plots because the inherent value present in untreated subjects of any scientific study is solely dependent upon the statistical comparison with control variables. Three control plots were present at each site, with the other two groups of three experimental plots (Round Up and Eco Clear).

As part of my monitoring regime, I conducted preliminary site and plot analysis one week after the construction and herbicidal application to my experimental plots in order to quickly analyze the variables and ensure the proper testing of the preferred segment of the population. For reference, this involved the confirmation that my constructed plots were actually continuing to contain V. rossicum, as the experimental variable. Essentially, I examined the efficacy of the plots to show results within their boundaries and within the greater plant population of the site, in accordance with proposed effects that the

14 scholarly literature documented. I confirmed that indeed, the plots of both sites worked effectively at segmenting the population that I was interested in examining throughout my experiment.

Unfortunately for the purposes of this experiment, the collection of desired quantitative variables such as variation in biomass and nutrient allocation over time was not possible. Ideally, I would have harvested the above-ground plant mass after the control methods were applied to the plots, in order to weigh the biomass and take tissue samples to analyze in a laboratory. However, the plant tissues were deemed a contaminated and toxic substance, so I used the precautionary principle and avoided taking this protocol. Instead, I observed the changes in the plants and recorded the percentage of damage done to the tissues over time, in each plot. This was much safer because I wouldn’t have to handle the herbicide-laden plants, but also provides an efficient tool for use by future students whom can thereby conduct their research safely, efficiently, and effectively.

The size of the plots was tailored to the size of the invaded site. For instance, the plots on the MTD site were one- by one-metre in size, and the plots on the LED site were two- by two-metres in size. The variation in plot size occurs because the LED invasion is nearly twice as large as the MTD and has less physical obstructions, such as mature trees as found in the forest of the south drumlin.

Morton Trail Drumlin site:

The first nine plots were established on Monday July 25, 2011, at the MTD site which is roughly 150m southwest of the University Road entrance (Figure 3). This site was historically a disturbed environment and has since become invaded by exotic plants. Remnants of an old dump site can still be recovered in this degraded forest ecosystem, owing to the disregard for nature in the past. The forest composition is mostly black locust (Robina pseudoacacia) mature overstory, European buckthorn (Rhamnus cathartica) mesostory, and herbaceous understory consisting of various grasses and herbs. The herbaceous understory presently has mixed native and exotic, shade-tolerant plants with one single obvious monocultural clump of V. rossicum. The plots were constructed as one- by one-metre quadrats, giving the plot an area of one metre-squared. Three of these plots were established for each of the two herbicides applications. The plots were established randomly within non-treed areas as to provide landscape congruency through the grouping of similar experimental control tests. All plots were positioned at least one metre from the other, to avoid overspray and residue conflictions which would alter the scientific results attained from this experimental design project. Plots were randomly allocated minus this confliction. All plots consisted of a four stakes driven into the ground, with bailer twine wrapped around the corners to visually contain the insides of the plot from the outside. We then proceeded to mark the four stakes of each plot with

15 bright orange marking paint to provide easy visibility, and finally, we assembled the pesticide warning signs and placed them at the front of each treatment plot. In the process of constructing the plots, we avoided disturbing the test plots to provide the most non-conflicting results possible.

The forest composition at this site was quite distinct from the other site. Here, the forest contains R. pseudoacacia trees that have diameters at breast height (DBH) of 85. However, the range of DBH in the V. rossicum infestations were smaller and younger, with an average DBH of 18.1 cm and height of 13 m. The canopy consumed most of the light in this environment, so only shade-tolerant plants could survive. The canopy was observed to cover 85% of the overstory. Additionally, this location seemed quite humid and moist during the summer, a testament to the shading effects (personal observation).

Forest Structure at Morton Family Trail Drumlin # of Trees DBH (cm) - Average Height (m) - Average Canopy Cover (%) 9 18.1 13 85

Figure 3 depicts the Morton Family Trail infestation site. This site is smaller, at 203 metres-squared, contains less tree density, and has higher average tree height and DBH

Photo 1 shows the dense understory infestation of V. rossicum under the overstory of a mature black locust forest

Figure 4: Location of south drumlin site, invaded by V. rossicum. Red circle denotes exact location of invaded site. Source: Trent University 2011.

Lady Eaton Drumlin site:

The second nine plots were established on Tuesday July 26, 2011, on the eastern portion of the Lady Eaton Drumlin (Figure 4). This particular thicket is located roughly halfway up the drumlin, within a relatively open landscape and vegetation that consisted of mostly understory herbaceous perennials, and sparse overstory of mature staghorn sumac (Rhus typhina) trees. The history of this specific area is similar to other early successional sites on the LED, and is a product of historical anthropogenic disturbance. The drumlin was formerly pasture land for agriculture and has since gone fallow, into a naturalized state (T.N.A. 1997). This naturalization process has allowed a vulnerability to invasion of this invasive exotic plant. Proceeding the naturalization after agricultural disturbance, the ecosystem gained vegetative structure with R. typhina trees but has since degraded in quality, unknowingly because of either old age of the stand or because of the impacts that V. rossicum. These staghorn sumacs, roughly 6 m tall on average, have likely finished invading the area following the new invasion of V. rossicum into the area. The plots constructed in this site were two-metre by two-metre quadrats and were established with similar methods as the South Drumlin site.

The composition of this site resembled that of an open meadow, with only 15% canopy cover and a dense ground cover of herbaceous perennials. There are 41 trees in the site, but only 20 were observed to be produce leaves during the summer, likely due to plant morbidity and mortality, potentially caused by interaction with allelopathic chemicals of V. rossicum. Additionally, the average DBH was 4.5cm and the average height was 6m, which demonstrates that this site is very young and only in the premature stages of succession. Forest Structure at Lady Eaton Drumlin # of Trees DBH (cm) - Average Height (m) - Average Canopy Cover (%) 41 4.5 6 15

Figure 5 depicts a 3-dimensional design of the LED infestation site. It is 268 metres-squared and as shown here, contains the nine 4 metre-squared plots within. The erected cylinders represent the 41 staghorn sumac (Rhus typhina) trees with average DBH of 4.5cm.

Photo 2 shows a picture of the LED site with the dense infestation of V. rossicum and mesostory of R. typhina

Figure 6: Location of eastern Lady Eaton Drumlin site invaded by V. rossicum. Invaded site located in red circle. Source: Trent University 2011.

3.4 Herbicide Application to V. rossicum

Herbicide was chosen as the main eradication technique for several reasons. Most research exists with regards to experimental eradication of V. rossicum using chemical herbicides (Lawlor 2000; Lawlor 2002), and they tend to be cost effective and time efficient for natural areas land managers . Therefore, it made the most sense to compare the efficacy of two different herbicidal applications on V. rossicum. Ideas of using mechanical methods were entertained at the outset, but dismissed after consideration of time and energy expenditure (McKague and Cappuccino 2005). The mechanical methods would prove intensive, consisting of digging, pulling, cutting, and smothering the plant. The chemical methods however, were very efficient with time and energy since all that was needed was a herbicide, a spray canister, and a professionally certified herbicide applicator person.

The choice of herbicides was not a difficult decision to make. The literature describes a pressing need that exists for research of environmentally safe herbicides in the context of plant invasions of natural areas. Abouziena et al. (2009) studied the effectiveness of new organic-compliant naturally-derived herbicides in laboratory settings, for the purposes of improving knowledge about weed control in organic agriculture. They include:

1. Alldown: Citric acid (5%) + garlic (0.2%) 2. Acetic acid (30%) 3. Corn gluten meal 4. Citric acid (10%) 5. Acetic Acid (5%) 6. Groundforce: Citric acid (10%) + garlic (0.2%) 7. Matran II: Clove Oil (45.6%)

This list is in order of most effective treatment for a broad range of broadleaf weeds that were shown in the study. The citric acid (5%) + garlic (0.2%) was shown to control 98% of weeds effectively, followed by acetic acid (30%) which controlled 91%. The next most effective herbicide was corn gluten meal which controlled 90%, followed by citric acid (10%) which controlled 75%. These results demonstrate that a combination of acetic acid citric acid may be an effective solution for controlling broadleaf weeds. Hence, the status of herbicides that contain this combination was researched, and the widely available product Eco Clear was found. Eco Clear uses solvents and surfactants as the inactive ingredients that compliment the citric acid and acetic acid active ingredients. This product was available from the Physical

Resources department at Trent University, and was used in the experiment as a comparative product to common synthetic, non-organic compliant petrochemical herbicide, Round Up, that uses water and an undisclosed surfactant as the inactive ingredients that compliment the active ingredient, isopropylamine salt of glyphosate. See Table 4 for further details.

The most important materials in this study to describe are the herbicides. The two are listed below in comparison with each other. Following is a description of the application methods, locations, and dates.

Table 4: Biopestidice Products Used in Foliar Spray Application Experiments on V. rossicum Product (chemical) Round Up Eco Clear Constituents (by weight % -49% (as acid equivalent), 66% as -25% Acetic acid per volume unit) Glyphosate isopropylamine salt -25% Citric Acid -1-10% Water -0.1-0.5% Solvent naptha -Surfactant (not disclosed) -0.1-0.3% 1,2,4 Trimethyl benzene

Control Pathway Systemic Deep-Tissue Herbicide Surficial Contact Herbicide Effect on tissues Residual Contamination Burn down Dilution for Application 20:1 2.5:1 Application Concentrations 5% 10% Sources: Round Up Pro MSDS and label (Round Up 2011), Eco Clear MSDS and label (Eco Clear 2011)

The application of the two herbicides occurred on July 28, 2011 on the South Drumlin and July 29, 2011 was the application on Lady Eaton Drumlin. The weather conditions were stable and dry both days, so spraying was conducted at roughly the same time of day. Only one application of each herbicide was needed on each day for the purposes of this study. One application to the V. rossicum infestations was hypothesized to be sufficient for both herbicides, at both locations. The glyphosate herbicide was applied at 3.1 kg ae/ha and the acid herbicide was applied at 750 L/ha. Both products were diluted appropriately in accordance with label instructions.

Eco Clear: General Information: The label for Eco Clear has been digitized for consumer interest (Eco Clear 2011). It describes the product as a postemergent, foliar active, vegetation management product developed with organic acids that are similar components of vinegar and lemon juice, except the concentrations have been elevated to burn plant tissues. Hence, it is non-selective to green foliage. Additionally, it is non-residual in soil as pH is equalized by the neutrality of soil moisture. This fact makes it potentially more environmentally safe than its competitor, glyphosate, also studied here. The label states, but does not reference peer-reviewed literature, that Eco Clear can be used in a variety of semi-natural settings that include railroad rights-of-

22 way, surrounding farm buildings, plan nurseries and greenhouses, golf courses, fencerows, and vacant lots. It describes the control pathways and effect on tissues as a foliar contact herbicide that results in rapid burn down of annual weeds and suppression (top growth reduction) of herbaceous perennial weeds. Most importantly, it states that retreatment is required for the complete control of established perennial weed. It is important to note here that only one application was used, since only one application was required for the competitor, Roundup. One treatment each was used to provide scientific congruency. As a reminder, the purpose of this study is to objectively study the effects of two herbicides with similar rates of application, and not to provide full eradication regardless of application rates.

Directions for Use: The label also states that results of most effective weed control is noticed during the spring and early summer, to younger-aged weeds. The efficacy of the control regime depends on a number of factors, including size and stage at application. The label proposes that retreatment of larger, established weeds may be needed if sufficient control efficacy is not noticed, since older perennial herbaceous weeds demonstrate more tolerance to this herbicide with corresponding decreases in observed morbidity versus second applications. Seedling perennial weeds found in spring and early summer need only one application. In addition to these plant-based considerations regarding application, the control regimen should avoid applying the herbicide on days where it is projected to rain within one hour after application.

These two subsections described are noted to be most relevant to this report. Additional information such as safety and specific application rates can be accessed from Eco Clear (2011)

Roundup:

The description of general information for Round Up is effectively very similar to that of Eco Clear. However, Round Up uses the salt of isopropylamine as a residual contaminant on plant tissues. It targets the foliage first, but systematically penetrates into the stalks and roots, providing systemic control with only one application. Additionally, the timing of application should be similar to Eco Clear. Further information can be obtained from Round Up (2011)

4. Results

A bi-weekly analysis was performed starting on August 2, 2011, one week after herbicide application . Therefore, it is an important date to know for interpretation, documentation, and presentation of results following the most achievable timeline of analysis, for the acting authorities, of the discrepancy and

23 effectiveness between sprayed and non-sprayed plots. This is a highly practical date to set since the herbicides should not be altered or tampered with for several days following application. With agreeable weather consisting of mostly sunshine and dry air, the Roundup (glyphosate) and Eco Clear (concentrated vinegar) should concentrate on foliage and destroy most contacted tissues over time, while leeching glyphosate molecules unto the remaining live portions of the stems and stalks. Eventually, with rain and atmospheric humidity, the glyphosate will leech further into the root system and overthrow the regenerative capacity of the vine, thereby killing it entirely. The Eco Clear however, seems to attack the tissues in a highly acidic manner, which burns the tissues much quicker and effectively, so long as the environment is sufficiently dry and open. If the environment is wet, and the acid drips off the plant tissues, it will likely be quickly neutralized by the soil. Hence, the effectiveness would become much less than if applied in proper conditions with proper foresight. The herbicide applications both caused discolouration and wilting, which was documented and recorded into a variable called percent damage.

Table 5 depicts the mean percent damage observed with variation from the mean (Var. +/-) between the three replicate plots of each herbicide treatment at each location Herbicide Week Var. Week Var. Week Var. Week Var. Treatment Location 1 +/- 3 +/- 5 +/- 7 +/- Round Up LED 12 3 38 5 65 4 100 - Round Up MTD 8 2 15 2 22 3 35 3 Eco Clear LED 25 4 28 3 35 2 45 4 Eco Clear MTD 5 1 12 2 15 1 17 2 No Herbicide LED 0 - 0 - 0 - 0 - No Herbicide MTD 0 - 0 - 0 - 0 -

Table 5 depicts the deviation between values of percent damage observed for both herbicide treatments at bi-weekly intervals Location Deviation Between Values LED Week 1 Week 3 Week 5 Week 7 Mean Dev. Round Up + 10 + 30 + 55 Eco Clear + 13 MTD Week 1 Week 3 Week 5 Week 7 + 36.5 Round Up + 3 + 3 + 7 + 18 Eco Clear

Figure 7 depicts the percentage of mortality observed at bi-weekly intervals, with two herbicide applications at two locations. LED = Lady Eaton Drumlin. MTD = Morton Trail Drumlin

Figure 8 depicts the linear regression trend lines associated with each treatment at each location.

Figure 9 Depicts the rate of damage per week associated with each treatment at each site

Table 6 depicts the linear regression equations and associated correlation coefficient (R) Mean Rate of Damage Treatment Location Linear Equations Slope R-absolute R-critical (% per week) Round Up LED y = 29.1x - 19 18.95 0.997346 0.950 14.6 Round Up MTD y = 8.8x - 2 0.986357 0.950 4.4 Eco Clear MTD y = 3.9x + 2.5 5.3 0.958645 0.950 1.9 Eco Clear LED y = 6.7x + 16.5 0.973653 0.950 3.4 Table 6 Rate of Damage = calculation of weekly damage done by each herbicide, derived from linear regression equation

5. Discussion

These results show that significantly more success in eradication of V. rossicum was achieved by the foliar application of Round Up, versus Eco Clear, on both the LED and MTD sites. This variation between results is likely not a product of herbicide effectiveness, but rather effectiveness at rates applied. Since only one application of Eco Clear was tested for all plots at both sites, it can be estimated that the Eco Clear treatments would prove more statistically effective at damaging plants with a second application.

It is interesting to note that the microclimates of both sites could have caused the variation between site- level effectiveness of herbicides. The combined plant damage caused by both herbicide treatments was 73% at the LED site and 26% at the MTD site. This represents a 47% increase in effectiveness on the

LED site, versus the MTD site, with the exact same herbicide and application rates. This may signify an interaction with the moisture and light regime of the environments, which ultimately caused the efficacy of the herbicides to vary significantly. It is possible that the thick, mature forest overstory of the MTD site created a microclimate that reduced the efficacy of both herbicides by shading and diluting. The shading of the MTD site is caused by the 70% increase canopy cover over the LED site, and diluting is caused by the increase in moisture observed as a result of the inhibition of light penetration.

5.1 LED Site: The differences between the herbicide effects noticed at the LED site are interesting to discuss. The rate of damage per week, calculated by halving the slope of the linear regression equation, shows that Round Up caused 14.6% damage per week and Eco Clear caused 3.4% damage per week at the Lady Eaton Drumlin site. This demonstrates that Round Up caused 4.3 times more plant damage per week than Eco Clear throughout the experiment, which dictates significantly more effectiveness of Round Up versus Eco Clear at this site. Specifically, it caused 55% more total plant damage than Eco Clear at the LED site. Within one week after application of the herbicide treatment, Eco Clear caused 13% more damage to plant tissues than Round Up, based on the visual analysis of the replicated plots. This may be due to the fast-acting constituents that cause immediate burning action, whereas Round Up is more of a systemic long-term acting herbicide, because of the persistent organic chemicals present as the active ingredients. On this note, Round Up likely penetrated the plant tissues more thoroughly over the next two weeks, causing a 10% increase in damage over Eco Clear at the third week. The fifth week showed that Round Up inflicted 30% more damage than Eco Clear, and at the seventh week, it had caused 55% more damage than Eco Clear. The overall effectiveness of Round Up at the LED was significant and resulted in 100% damage to plants at the seventh week. Eco Clear had damaged 45% of plants by the seventh week, 2.2 times less than Round Up, and therefore demonstrates far less effectiveness in this location at the application rate.

5.2 MTD Site: Round Up was also the most effective herbicide on the MTD site, although the rate of damage for both Round Up and Eco Clear was less than the LED site. The rate of damage for the MTD site shows that Round Up caused 4.4% damage per week, whereas Eco Clear caused 1.9% damage per week. Although both treatments proved less effective at the MTD site versus the LED site, the Round Up was 2.3 times more effective than Eco Clear at this site. Round Up caused 18% more plant damage than Eco Clear at the MTD site. Roundup and Eco Clear caused near equal damage after one and three weeks, with Round Up providing 3% and 3% more damage respectively. After five weeks, Round Up damaged 7% more plant

27 tissue than Eco Clear. By the seventh week, it had damaged 18% more plant tissue than Eco Clear at this site. Overall, the effectiveness of both herbicides was reduced at this particular site, but Round Up still remained the most effective herbicide.

5.3 Variation in Effectiveness Between LED and MTD Site: Round Up collectively caused 36.5% more damage than Eco Clear plots located in both sites, which clearly shows that it demonstrates more effectiveness as a herbicide at the rates applied. Eco Clear was not as effective long-term, by the end of seven weeks in both sites. It is interesting to note that efficacy differed significantly between the two sites, perhaps because the LED site is more open and dry, which contributes to an increased efficacy of both herbicides (Round Up 2011; Eco Clear 2011). The Round Up and Eco Clear demonstrated more effectiveness at the LED site because the chemicals adhered to the plant tissues better, and were not diluted by persistent moisture of the environment, such as that of the densely shaded forest of the MTD site. Another interesting result was shown by the initial effectiveness of Eco Clear on the LED site, where Round Up was actually slower to cause damage within the first week, but prevailed over Eco Clear, and eradicated more percentage of plant tissue. It is important to state a second time that the variation between results is likely not a product of herbicide effectiveness, but rather effectiveness at rates applied. Since only one application of Eco Clear was tested for all plots at both sites, it can be estimated that the Eco Clear treatments would prove more statistically effective at damaging plants with a second application.

6. Conclusions and Recommendations

In conclusion, it has been demonstrated that Round Up is the most effective chemical treatment for controlling the invasive exotic perennial vine, V. rossicum, in two different environments of the Trent University Nature Areas. The percentage of damage inflicted to the plant is nearly double in both sites after one application of each herbicide. These results are significant, but should be considered in the context of application rates. Since only one application of Eco Clear was studied, it should be further researched whether two applications cause percentage of damage to V. rossicum that is equal to one application of Round Up. This should be studied to determine whether Eco Clear at two applications, or Round Up at one application, is the most effective and environmentally safe herbicidal eradication technique.

This study is important for monitoring the ecological responses that continue into the future. The issue of invasive plant management, particularly with V. rossicum is gaining recognition by various sectors of society that share the concern for the economic and ecological impacts. Continuing with the final four

28 strategies adapted from a strategic plan by Havinga (2000) will finalize the strategies involved with this report. The following four points detail the necessary steps involved with this report and future implementation of regimes, brought forth by its impact on those who read it. It is important to view these strategies as next steps to take, as if an invasive plant management program were to be established.

1. Communicate implications of results In order to reach out to audiences that have little to no scientific background in modern ecological conservation problems, a method of communication must be developed that includes scientific rationale packaged in lay terms. Creating a working group that can identify target groups, topic, and tools for education can help progressively increase awareness of the topic, and eventually create activities to help the situation. The target groups with regards to this report are the Trent Nature Areas committee who act as the community for which further development and implementation of strategic plans can occur.  Circulate the report to interested individuals within the concerned community  Post the plan and supporting documents on websites or publish in newsletters  Create focus groups to gather ideas about the report  Incorporate invasive plant management guidelines into the policies that already exist within the institution  Educate institutional environmental groups about the issue and propose ideas for stewardship  Create brochures, information packages, and fact sheets regarding invasive plants and their management for a user-friendly audience

2. Revise policies and develop appropriate protocol The implications of policy can be numerous, and include a mandate for the prevention of plant invasions by direct actions into the future. Policies should be assessed and revised in order to create new, current policies where outdated ones exist.  Implement a ban on the transport or use of invasive exotic materials in the locale  Clearly focus on prevention by, for example, establishing strong policies that improve native plant communities in invaded areas  Develop or revise by-laws that call for eradication of all invasive plants on the property  Review policies of other institutions to collect ideas

3. Create plans of action

The resources needed for managing plant invasions come from maintenance staff and volunteer clubs, whom provide strength in numbers needed to combat this issue. The issue may present a large challenge, but action campaigns can encourage more practical involvement with communities of people, and build partnerships that grow into the future, while increasing awareness about the issue.  Develop a campaign for the institution that encourages active stewardship

4. Promote collaborations and partnerships Integrating all the aspects of the seven previously mentioned strategies toward managing invasive plant populations, the promotion of partnerships is the final stage in this eight-stage process. It involves collecting and disseminating input regarding the scope of the problem in areas of concern. The pooling of many resources from these groups can help reduce the overwhelming complexity of certain situations, and reduce the burden of responsibility for each individual in the group. Therefore, it is a keystone strategy that unlocks the potential of a community to take direct action on important issues of ecological restoration and environmental stewardship.

7. Acknowledgements

I would like to acknowledge the Nature Areas Committee at Trent University for their assistance and encouragement. Bill Forsyth, Rob Loney, and Tom Whillans all provided generous support and advice throughout the project.

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