**3. The setting**

*Plant Communities and Their Environment*

direct sunlight [22, 23].

category [22, 23].

forest ecosystems.

**2. Taxonomy and physiological basis for study**

Eastern poison ivy is a member of the Anacardiaceae family (sumac-cashew)

All species within the *Toxicodendron* genus show some tolerance to soil salinity, and this provides the plants with the ability to maintain viable populations within disturbed habitats [22]. Kuester et al. [26] reported that elevated tolerance to soil salinity was a common characteristic of successful weed species in North America. The United States Department of Agriculture (USDA) Plants Database (http:// plants.usda.gov/charinfo) provides a standard definition to represent how plants tolerate soil salinity. Such representation of plant tolerance to soil salinity reflects studies of plant growth performance that classified species among four tolerance categories (zero, low, medium, high), to represent range of responses. These USDA responses include zero tolerance to soil solutions with electrical conductivity of 0–2 dS/m, low tolerance to 2.1–4.0 dS/m, medium tolerance to 4.1–8.0 dS/m, and high tolerance to >8.0 dS/m. Plants are defined to tolerate salinity if there is zero to slight reduction in growth (<10%). Eastern poison ivy demonstrates an ability to tolerate elevated concentrations of soil salinity, often within the medium tolerance

Such reports of tolerance of EPI to soil salinity include a range of responses, depending on the locale of the study [22, 23]. It is likely this range of responses is a direct response to rhizome growth forms with roots and stems extending over large areas. This pattern indicates that the rhizome allows the plant to tolerate a wide range of soil salinities, as well as other forms of local disturbance. The presence of rhizome growth form was identified as the causative factor for rapid reestablishment of EPI after flooding destroyed surface stems and leaves [27, 28]. The observation of tolerance of EPI to environmental disturbance, due to ecological and physiological adaptations, justifies the consideration of EPI as a candidate bioindicator species. The use of EPI as a bioindicator species identifies that the phenological response patterns of the species to different environmental, ecological, and physiological factors is understood. This chapter demonstrates the current understanding of the responses of EPI and plant communities near HEAs and two natural seeps and represents an illustrative example of plant phenology in field and

and distributed across Eastern North America, whereas western poison ivy (*Toxicodendron rydbergii* (Small ex Rydb.) Greene) is distributed across Western North America [22, 23]. These two species are morphologically variable (e.g., leaf color, size, shape), and they can hybridize within overlapping habitats. Eastern poison ivy shows varied growth forms, with the most common as a woody rhizome that grows underground in all directions, with no nodes but roots and leaves at varied intervals. This variable rooting leads to the establishment of patches over large areas and varying types of soil. An alternate form of EPI demonstrates a woody vine that will climb trees and other hard surfaces. Both growth forms are identified as shade-intolerant and are often found in habitats with direct sunlight such as the edge of forests, along roadways, disturbed areas, fields, and wetlands. Both forms produce the toxin urushiol as a defense mechanism, and these toxins often cause contact dermatitis in two of three humans following exposure to as little as 1 nanogram [24]. These toxins are released from the roots and leaves to the air as oil droplets [24]. On Manitoulin Island, EPI is most commonly found along edges of forests and farm fields, roadways, and other disturbed areas [25]; EPI is considered a rare species in natural forests with closed canopies and wetland areas on the island [25], as this species prefers

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At WUT, oral history combined with TK led to the initial documentation of old and un-abandoned HEAs that were observed to be harming native vegetation as well as fouling agricultural fields. Specifically, resident observations included woody vegetation downslope of old HEAs that were dead or showed dead branches and short height compared with specimens in adjacent habitats that were live and taller. Other observations included livestock that shun hay cut from a field with an HEA releasing an oil-water slurry downslope through the field. These observations led to the abandonment of these HEAs. After these HEAs were abandoned, Premier was invited to participate in the discovery of lost HEAs, and this recent work represents the basis for this study.

It is prudent to briefly review the history of how HEAs were established at WUT during the 1800s, reflecting oral history, government reports, scientific articles, photographs, and letters written by Jesuit missionaries. This history also reveals that an extremely large forest fire occurred across Manitoulin Island during 1865, with areas on WUT having nearly all woody stems burned, and this land described afterward as fully cleared, whereas some wet areas and shorelines were spared [25, 29]. This regional fire disturbance at WUT likely aided development of HEAs, through enhancement of access following the loss of dense forest tracts. A second regional disturbance within the WUT forest has been the recent loss of ash (*Fraxinus* spp.) trees due to invasion by emerald ash borer (EAB, *Agrilus planipennis*). This beetle from Asia invaded southern Canada during the early 2000s and now has spread extensively within North America [30]. At WUT, most ash have perished during the last decade, including black ash (*Fraxinus nigra* Marshall), green ash (*F. pennsylvanica* Marshall), and white ash (*F. americana* L.) due to the EAB infestation.

Initial advancement of HEAs at WUT occurred during the summer of 1865 while other portions of the island burned [31, 32]. The first HEAs were planned to focus on oil and followed the McDougall Treaty involving WUT and Upper Canada, signed during 1862; it is noteworthy to identify that the WUT community did not fully embrace this treaty as only two community members actually signed the document [32, 33]. After this treaty, staff from Milwaukee Petroleum Company arrived at WUT on May 1 of 1865 to negotiate access. After access was tentatively granted by WUT, John Ward, an experienced pioneer in oil well drilling from Oil Springs, Ontario, arrived about a month later. Mr. Ward focused the drilling activity on limestone outcrops found in close proximity to natural oil seeps evident along Smith's Bay shoreline, an area directly accessible by boat. This initial extraction activity yielded a "schooner load" of oil that was shipped south with a request for 500 wooden barrels to be shipped north. However, the oil extraction ended during autumn in 1865 when the Wiikwemkoong community members asked the oil men to leave on short notice; their equipment was reportedly left behind [31, 33].

Representatives from the oil industry returned to WUT during the early 1880s and proceeded to develop a large number of HEAs despite opposition from the community [33]. This development was approved by the Government of Canada, as oil well licenses facilitated access to WUT for lease areas along the recently described Trenton Formation. When these 1880s HEAs were prepared, the initial disturbance involved road construction, as land away from the shoreline was targeted. After roads were prepared, HEAs were constructed in agricultural fields and forest settings. In agricultural fields, site preparation was a relatively simple activity, while forest settings required additional effort. It is probable that some of these forest areas used for HEAs in the 1880s were burned during 1865 and included younger trees. After a site was cleared, then a wooden oil rig was built around the extraction

point. A wood barrel was then usually placed next to the rig, to collect the oil-water slurry; natural gas wells also had a collection barrel. These barrels allowed for the separation of oil and water via gravity, but it is not clear if it was necessary to separate water from the natural gas. Abandonment studies to date have revealed collection barrels in agricultural fields which were placed on grade, while in the forests, they were buried. Collection barrels documented at WUT in fields had dimensions with a width of 3–4 m and height of 3–4 m, while barrels abandoned during 2016 in forests had widths of 3–4 and depth up to 6 m [21]. This design implies the larger barrels needed to be placed below grade, to support the weight and facilitate gravity separation of the oil and water slurry [21].

All wells were drilled by hand, with help from horses. Abandonment studies led by WUT from 2014 to 2017 years revealed the depth of the drilled holes ranging from 105 to 130 m for oil sites and up to 337 m for natural gas [21]. The presence of porous limestone of the Trenton Formation across WUT provides a simple explanation why the HEAs involved this range of depths. These depths also reveal that the wells could have been more shallow, as it is now known that these depths penetrated the hydrocarbon-bearing strata and then entered the deep groundwater strata [34]. It was reported [34] that drilling of hydrocarbon wells in Ontario during the 1800s and 1900s included the systemic problem of over-drilling oil strata followed by penetration of deep groundwater. When an oil well is over-drilled, it is often associated with initial high yields of an oil-water slurry; however, the longevity of the well is shortened due to the high volumes of water that are interacting with the oil at depth. In the case of the natural gas wells at WUT, it appears they did not produce excessive quantities of water, based on abandonment activities [21].

Hydrocarbon extraction at WUT ended in 1905, after 20+ years, when the men were evicted and the structures burned [21]. Pipes at HEAs were often cut below grade. Then, some pipe holes were filled with soil and rock, and graded, to reduce risk from falling in to these hazards. This history identifies that all known HEAs were burned, indicating a common disturbance history for the forest and field settings. This 1905 burning followed the 1865 forest fire, representing key disturbance events shaping the plant communities associated with most HEAs at WUT. After this period, many HEAs near or within forests experienced regeneration, although the species composition of trees differs from historical forest composition (described below). In contrast, HEAs located in agricultural fields were often maintained as fields, through regular cutting of the herbaceous vegetation. Studies [15] at WUT documented that for seven HEAs, the soil concentrations of hydrocarbons were elevated in close proximity to HEAs, but these concentrations rapidly declined with distance from the HEAs. This elevation of hydrocarbons at an HEA was attributed to extraction while the lower concentrations attributed to bacterial degradation of hydrocarbons downslope. These low concentrations of soil hydrocarbons downslope from HEAs provide additional evidence that it is brine causing disturbance to the plant communities [21].

This study considers the diversity and distribution of plants and EPI associated with HEAs located in forest and field settings at WUT, as described in **Table 1**. These plant associations reflect past field surveys that focused on the common plants [25] near HEAs. Initial observations at HEAs revealed that the plant community was less diverse and these plants were distributed in what was documented as a predictable manner in proximity to HEAs and this led to the preparation of this study [21]. Hence, this study does not focus on the morphological or phenological aspects of plant specimens near or around HEAs. However, aspects of morphology and phenology are considered while interpreting the diversity and distribution of plants in forest and field settings associated with HEAs.

**109**

presence of brine at HEAs.

**5. Results**

**Table 1.**

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

**Site (current habitat) Plant association with EPI HEA** A (forest) Ostrich fern (*Matteuccia struthiopteris* L.), balsam poplar (*Populus* 

D (forest) Smooth Solomon's seal (*Polygonatum biflorum* Walter), balsam

H (field) Timothy *Phleum pratense* (L.), Virginia strawberry (*Fragaria* 

*At each site, the main plant association with EPI and HEA is noted along with the type of HEA.*

*virginiana* Duchesne)

B (forest) Marsh horsetail (*Equisetum palustre* L.), balsam poplar Metal pipe C (forest) Ostrich fern, balsam poplar Metal pipe

E (forest) Common lady fern (*Athyrium filix-femina* L.), balsam poplar Wood crib F (forest) Common lady fern, balsam poplar Wood crib G (field) Red osier dogwood (*Cornus sericea* L.) Metal pipe

I (field) Timothy, Virginia strawberry Metal pipe J (roadside ditch) Raspberry (*Rubus arcticus* (L.), Virginia strawberry Metal pipe K (field) Virginia strawberry Natural seep

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

*balsamifera* L.)

poplar

**4. Chemistry of water from HEAs and seeps**

*Summary of forest and field sites considered in this study.*

*Plant identifications follow the standard guide for Manitoulin Island [25].*

Studies of oil and gas wells generally, as well as for those located across the Trenton Formation, revealed brine is readily evident and the chemistry reflects local limestone composition [19, 20, 35]. Hence, wells within a short distance can show variations in concentrations of key elements. General features of brine within the Trenton Formation describe this water as having a near neutral pH (5.5–7.0) with elevated concentrations of elements that can be described generally as follows: Cl >100,000 mg/L, Na >50,000 mg/L, Ca > 20,000 mg/L, Sr. > 5000 mg/L, Mg

and Fe > 300 mg/L [19, 35]. This general composition of brine represents concentrations of elements that are potentially harmful to aquatic and terrestrial life and why this water is regulated under Ontario's *Oil, Gas and Salt Resources Act*. This need to control the release of brine can be illustrated by considering the Cl surface water quality guideline in Canada to protect aquatic life during short-term exposure is 640 mg/L and long-term exposure is 120 mg/L [36] while brine may contain Cl at >100,000 mg/L. Thus, water from HEAs can be regarded as hazardous to plants and wildlife, even in small quantities. Water samples collected by WUT confirmed the

Integration of available information from WUT, scientific literature, and field inspections allowed for the identification of a list of plants associated with HEAs in field and forest habitats (**Tables 2–4**). The first forest habitat type is dominated by balsam poplar (*Populus balsamifera* L.) and the second forest habitat dominated by balsam fir (*Abies balsamea* L.) and eastern white cedar (*Thuja occidentalis* L.). When the plant associations with HEAs were identified, they were intended to represent spatial patterns concerning the general plant community found in each area, as

–2 > 500 mg/L,

Wood crib

Metal pipe

Metal pipe

>2000 mg/L, K > 2000 mg/L, Ba >2000 mg/L, Bo >1000 mg/L, SO4

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic… DOI: http://dx.doi.org/10.5772/intechopen.88150*


*Plant Communities and Their Environment*

separation of the oil and water slurry [21].

abandonment activities [21].

causing disturbance to the plant communities [21].

plants in forest and field settings associated with HEAs.

point. A wood barrel was then usually placed next to the rig, to collect the oil-water slurry; natural gas wells also had a collection barrel. These barrels allowed for the separation of oil and water via gravity, but it is not clear if it was necessary to separate water from the natural gas. Abandonment studies to date have revealed collection barrels in agricultural fields which were placed on grade, while in the forests, they were buried. Collection barrels documented at WUT in fields had dimensions with a width of 3–4 m and height of 3–4 m, while barrels abandoned during 2016 in forests had widths of 3–4 and depth up to 6 m [21]. This design implies the larger barrels needed to be placed below grade, to support the weight and facilitate gravity

All wells were drilled by hand, with help from horses. Abandonment studies led by WUT from 2014 to 2017 years revealed the depth of the drilled holes ranging from 105 to 130 m for oil sites and up to 337 m for natural gas [21]. The presence of porous limestone of the Trenton Formation across WUT provides a simple explanation why the HEAs involved this range of depths. These depths also reveal that the wells could have been more shallow, as it is now known that these depths penetrated the hydrocarbon-bearing strata and then entered the deep groundwater strata [34]. It was reported [34] that drilling of hydrocarbon wells in Ontario during the 1800s and 1900s included the systemic problem of over-drilling oil strata followed by penetration of deep groundwater. When an oil well is over-drilled, it is often associated with initial high yields of an oil-water slurry; however, the longevity of the well is shortened due to the high volumes of water that are interacting with the oil at depth. In the case of the natural gas wells at WUT, it appears they did not produce excessive quantities of water, based on

Hydrocarbon extraction at WUT ended in 1905, after 20+ years, when the men were evicted and the structures burned [21]. Pipes at HEAs were often cut below grade. Then, some pipe holes were filled with soil and rock, and graded, to reduce risk from falling in to these hazards. This history identifies that all known HEAs were burned, indicating a common disturbance history for the forest and field settings. This 1905 burning followed the 1865 forest fire, representing key disturbance events shaping the plant communities associated with most HEAs at WUT. After this period, many HEAs near or within forests experienced regeneration, although the species composition of trees differs from historical forest composition (described below). In contrast, HEAs located in agricultural fields were often maintained as fields, through regular cutting of the herbaceous vegetation. Studies [15] at WUT documented that for seven HEAs, the soil concentrations of hydrocarbons were elevated in close proximity to HEAs, but these concentrations rapidly declined with distance from the HEAs. This elevation of hydrocarbons at an HEA was attributed to extraction while the lower concentrations attributed to bacterial degradation of hydrocarbons downslope. These low concentrations of soil hydrocarbons downslope from HEAs provide additional evidence that it is brine

This study considers the diversity and distribution of plants and EPI associated with HEAs located in forest and field settings at WUT, as described in **Table 1**. These plant associations reflect past field surveys that focused on the common plants [25] near HEAs. Initial observations at HEAs revealed that the plant community was less diverse and these plants were distributed in what was documented as a predictable manner in proximity to HEAs and this led to the preparation of this study [21]. Hence, this study does not focus on the morphological or phenological aspects of plant specimens near or around HEAs. However, aspects of morphology and phenology are considered while interpreting the diversity and distribution of

**108**

**Table 1.** *Summary of forest and field sites considered in this study.*
