THE NATURAL VALUES
AND ECOLOGICAL SIGNIFICANCE
OF
THE PETRIE ISLANDS
Prepared by Christine Hanrahan with Stephen Darbyshire
on behalf of the Conservation Committee of the Ottawa Field-Naturalists’ Club
November 1998
For Submission to the Regional Municipality of Ottawa-Carleton
Summary
The Petrie Islands lie close to the South shore of the Ottawa River within the Township of Cumberland. Although designated by the Ministry of Natural Resources as Provincially Significant Wetland and as an Area of Natural Significance, and also having similar Regional recognition and being owned by the Region, the Islands are the subject of both Regional and Municipal development consideration. In this brief the Ottawa Field – Naturalists’ Club describes the ecology, plant and animal life of these islands, objects to plans for their development, and outlines measures that would protect their ecology while allowing passive recreational uses similar to those proposed by the Friends of Petrie Island,
The Petrie Islands lie close to shore in the Ottawa River within the Township of Cumberland. These islands are a series of alluvial deposits forming a wetland complex of elongate sedimentary ridges and backwaters characteristic of the Ottawa River below the confluence with the Gatineau River. Along with Kettle Island and the Duck Islands, Petrie Islands form a unique landform in the region chronicling the powerful geological forces which shaped the face of our country. The sand and clay sediments that make up these islands were created by the massive ice – sheet that ground and polished the continent 10,000 years ago. Crushed by the continental glaciers from the rocks further north, the sediments were carried down the Ottawa and Gatineau Rivers. The river became a major route for plants and animals moving into Canada after the glaciation. Fine sediments would have provided the closest thing to soil available on the denuded landscape. From the patterns of plant distribution we can still see the effects of these processes today.
The unique habitats of the river corridor contain many plant species which reached their migrational limits along the flood plain forests and shores. Many species of plants can only be found in the region along the flood plain of the Ottawa River. Some of these plants require water systems and flooding for their seeds to be dispersed. Some need the continual shifting of shoreline sediments, while others need their habitat to be inundated in the spring but dried out in the fall. All of the plant communities found on the Petrie Islands are specially adapted to extensive spring flooding.
The power of the river and its seasonal fluctuations have shaped these islands and made them a special habitat for plants and animals. The islands are almost completely flooded in the spring. Flooding of the forests on the islands is a special feature that many species are adapted to and may even require to maintain healthy populations. Continual erosion and deposition of sediments around the islands provides a renewal of shoreline habitats and an evolution of plant and animal communities. The quiet backwaters are extremely rich habitats providing shelter and abundant nutrients for a wide variety of plants and animals not found in the open river. The diverse mosaic of habitats, high energy river shores, seasonally flooded forests, quiet backwaters, sand dunes, fertile clay soils, are all formed from the same processes, unique in the region to the Ottawa River. It is this variety of habitat that supports the many plants and animals of Petrie Islands.
At one time the types of habitats and communities
found on Kettle Island, the Duck Islands and Petrie
Islands would have been common along much of the Ottawa
River shores between Ottawa and Montreal. Today, flooding
and water level control from hydroelectric projects,
development, shoreline armouring and farming have
transformed the flood plain habitats. The natural
environment of the shores, forests, and backwaters along
the Ottawa River has all but disappeared and is long past
regeneration, apart from a few areas such as the Petrie
Islands. (Written by Stephen Darbyshire)
II. The Future of the Petrie Islands
The Petrie Islands are owned by the Regional Municipality of Ottawa-Carleton and are within the Township of Cumberland. The wetland complex, which covers most of the islands, has been designated by the Ontario Ministry of Natural Resources (OMNR) as Provincially Significant Wetland as well as an Area of Scientific and Natural Interest (ANSI). The Regional Official Plan designates most of the islands and the shoreline as Provincially Significant Wetland, while the small areas of high land and the sand extraction operation are designated Waterfront Open Space. The north side of the North Service Road on the mainland is listed as General Urban Area in the Official Plan – Schedule B. The Regional Official Plan acknowledges the importance of protecting the islands’ natural environment for wildlife, particularly waterfowl, and for the significant plant species onsite. The plan also recognizes the value of the islands for outdoor recreation. Under Cumberland’s Official Plan, the islands are designated Open Space, with no recognition of their provincial and regional status as significant wetlands. Cumberland recognizes the potential for both passive and active recreation on the site, and notes the conservation values of the area.
The Township of Cumberland has prepared a ’Petrie Islands Master Plan’ (1998) delineating their vision for the future of this site. Their plan would divide the islands into passive and active recreation areas, The passive recreation portion would include several large picnic areas and nature trails, while the active recreation section would be the site of the proposed marina complex. This complex could include amongst other features, an amphitheatre, club house, restaurant and large parking areas.
The islands are also viewed by the Region and by Cumberland as a potential site of the much-discussed new bridge across the Ottawa River. While a bridge may at first glance seem to be less destructive of the natural environment than a marina complex, in reality bridge development brings its own set of disruptive forces which can wreak long-term degradation on the site.
The Petrie Islands represent one of the few remaining scraps of natural habitat left along the river between Ottawa and Montreal that is close to an original state. We are concerned that Cumberland Township has not recognized the provincial significance of the Petrie Islands wetlands, and appears to place both active and passive recreation before conservation. We would like to encourage the Township to bring its designations into line with those of the province and the region. Compromising the fragile natural characteristics of the Petrie Islands with development and/or construction will result in the loss or degradation of an irreplaceable part of our heritage. Therefore, the Ottawa Field-Naturalists’ Club objects to the proposed Marina complex and any other large or small scale commercial development, as well as the proposed bridge across the Ottawa River at Petrie Islands.
The best option would be to leave the islands as they are, with no further interference. However, if changes are to occur, we believe that the next best choice is using the area for passive recreation such as nature study, hiking, picnics and swimming, as defined by the Friends of Petrie Island (1998). Increased usage by humans brings its own set of problems and a degree of supervision will be required if the natural values are to be protected. Certain ecologically sensitive areas of the islands should be protected from excessive human intrusion, These areas include turtle and bird nesting areas, and other key wildlife habitats, and locations of significant plant species. Such areas would be identified during thorough wildlife inventories of the islands. Great care should be taken in locating new trails and the areas should be assessed first to determine whether the trails will. have a negative impact on wildlife usage. During the summer breeding season, birds are particularly vulnerable to disturbance, especially those species which nest in low shrubs or on or near the ground. We believe that scouting the area first with a knowledgeable naturalist will alleviate most of these problems.
New trails should be just wide enough to allow easy movement, but not as wide as the recreational trails in the region which are approximately 12 feet in width. We prefer to see the trails remain grassed or otherwise natural, emulating the majority of the NCC Greenbelt trails, rather than overlaid with hard material. However, we also recognize that in some situations an artificial surface may be necessary, for example when a trail receives such heavy use that the vegetation wears away leaving a bare or muddy surface which users may skirt around inadvertently widening the trail, sometimes to a considerable width, and destroying adjacent vegetation. Wood chips (or bark mulch), while a ’natural’ material are not suitable for use on the islands because the fast flowing spring floods would quickly remove them. Stone aggregate materials or local limestone stepping stones in muddy places provide a durable and long-lasting alternative to paving which we feel is too intrusive in a natural setting. On the whole, we believe that the annual flooding of the islands would have negative effects on any surfacing material, even paving. Therefore, we reiterate that our preference is for natural trails, with the occasional cutting or brushing out to keep them open.
Interpretive signage at the trail-head as well as judiciously placed along the nature trails will help visitors understand the unique environment of the Petrie islands. Information can be given on such aspects as the formation of the islands, significant plant species (e g the hackberry trees), and wildlife usage. A brochure on the natural history of the islands can be carried by visitors as they traverse the trails, helping teach the special significance of the area. Alternatively, an interpretive trail guide brochure highlighting significant features along the trail can be produced, along with brochures on the birds and the plants of the Petrie islands. The Conservation Committee of the Ottawa Field-Naturalists' Club is willing to assist the RMOC and the Friends of Petrie island with these suggestions.
No list of flora or fauna is ever complete and that is
certainly true of the data supplied with this document. We
consider the attached lists preliminary and stress that further
work would produce a substantial increase in plant and animal
species observed.
The forested portions of the islands, containing a variety of
trees about 60 - 80 years old, were divided into 6 zones by Dugal
in 1977. Mature specimens of butternut (Juglans cinerea),
bitternut hickory (Carya cordiformis), basswood (Tilia
americana), red ash (Fraxinus pensylvanica) black ash (F. nigra),
and hackberry (Celtis occidentalis) observed during the 1977
survey, still remain along with hybrid silver/red maples (Acer
saccharinum x A A. rubrum).
A thorough survey of the flora of this area has yet to be carried
out, but the preliminary list compiled by Albert Dugal in 1977,
with additions by Stephen Darbyshire in the 1980's and 1990's, by
Dan Brunton during the same time frame, and casual observations
by others during 1998, has resulted in an impressive list of
plants (Appendix A). Of special interest is the extensive stand
of hackberry which Dugal (1977) calls the "greatest known
concentration...in the Ottawa district." Two plant species
found on the islands are considered of provincial significance.
One of these, Gattinger's Panic Grass (Panicum gattingeri) is
known within the region only on Petrie Islands (Brunton 1998).
Petrie Islands is also the only currently known location in the
RMOC for the regionally rare Mossy Love Grass (Eragrostis
hypnoides) (IBID).
Our preliminary list shows twenty-nine significant plant
species occurring on the Petrie islands. Significant species are
those regarded as regionally or provincially rare or sparse. Rare
is defined as "3 records or less" by Gillett and White
(1978), and "5 or fewer contemporary populations, (post
1969)" by Brunton (1998). Sparse is defined as "4 to 12
records" by Gillett and White, and "6 to 10
contemporary populations (post-1969)" by Brunton. Many other
plants found on the Petrie islands are considered regionally
uncommon, defined by Gillett and White as "not often found
even in suitable habitats, usually in small numbers, more than 12
records". We have listed only those native species
identified as regionally significant by Gillett and White, and
Brunton, at the end of Appendix A.
A comprehensive survey of the avifauna of the Petrie Islands
has not yet been conducted. However, between 1994 and 1998, Tony
Beck recorded his sightings of birds during this period, and his
data together with sightings by several other naturalists have
combined to produce a list of 109 species observed to date.
It is no surprise that the diversity of habitat attracts an
equally diverse number of birds. The extensive wetlands,
backwaters and the Ottawa River shoreline provide habitat for
birds such as pied-billed grebe, American bittern, great blue
heron, American coot, and a variety of waterfowl, shorebirds,
gulls and terns, belted kingfisher, and red-winged blackbird. The
woods and shrubby thickets host woodpeckers such as the large
pileated woodpecker, flycatchers, black-capped chickadee, house
wren, thrushes, vireos, warblers, rose-breasted grosbeak, and
purple finch. Edges and open areas are used by various sparrow
species, American goldfinch, gray catbird and brown thrasher. All
six species of swallows found in the Ottawa area have been
observed on the Petrie Islands. A complete list of all birds
observed is provided in Appendix B.
Bird usage is greatest during the spring and fall migrations when flycatchers, thrushes, flocks of warblers, and a variety of other birds use the area as a stopover point for resting and feeding. Many birds also find the quiet woods and backwaters conducive to nesting, and a breeding bird survey of the islands would be useful in determining more precisely the number of nesting birds. Winter sees the fewest birds, but year-round residents such as black-capped chickadees and downy woodpeckers are sometimes joined by winter visitors such as evening grosbeak, snow bunting, and in one recent winter, a great gray owl. In the cold months, many birds move from one area to another foraging for food, and it is during this time of year that birds such as great horned owls may be found along with small flocks of overwintering birds from adjacent areas.
Surveys specifically targeting butterflies have not been
conducted and the butterfly list (Appendix C) consists entirely
of casual observations by naturalists Joyce and Allan Reddoch,
Christine Hanrahan, David Hobden, and especially Peter Hall who
contributed 50 % of the sightings. Twenty-two species have been
recorded to date.
The list of mammals observed on Petrie Islands is given in
Appendix D. The relatively small size of the islands, as well as
the mix of habitat, would not be expected to support a great
diversity of mammals. However, small mammals such as weasels,
moles and mice are often difficult to census without some form of
small-mammal trapping (using live-traps), therefore a mammal
survey would undoubtedly reveal more than the nine species
reccrded to date.
Five species of turtles, including one introduced species
(Darbyshire 1997), have been recorded, along with three frog
species and one species of snake. As with all other surveys
noted, a more intensive study should find further additions to
this list (Appendix E).
REFERENCES
Brunton, Dan. 1998. Distributionally Significant Vascular Flora of the Region of Ottawa – Carleton. Prepared for the Regional Municipality of Ottawa – Carleton, 36p.
Brunton, Dan and Bruce Di Labio.1997. The Flora of Ottawa River Emergent Beaches. Trail & Landscape, 31: 109 – 123.
Cumberland Planning Department. July 1998. Petrie Island Master Plan, Background and Issue Paper, 15p.
Darbyshire, Stephen. 1986. More on the Bladdernut Shrub. Trail & Landscape 21: 26-28.
Darbyshire, Stephen. 1997. A Red-eared Slider in the Ottawa River. Trail & Landscape, 31:157 – 160.
Dugal, Albert. 1977. Petrie Islands Woods Resource Inventory. Prepared on behalf of the Ottawa Field-Naturalists’ Club for submission to the RMOC, 1 1p.
Friends of Petrie Islands. 1998. Petrie Island. Report to Cumberland Council, October 1998. Presented by Al and Helen Tweddle, 4p.
Gillett, John M. and David J. White. 1978. Checklist of Vascular Plants of the Ottawa- Hull Region, Canada. National Museum of Natural Science, Ottawa. 155p.
VASCULAR PLANTS OF PETRIE ISLANDS
TREES
| Acer saccharinum x A. rubrum | Silver Maple x Red Maple |
| Carya cordiformis | Bitternut Hickory |
| Celtis occidentalis | Hackberry |
| Fraxinus nigra | Black Ash |
| Fraxinus pennsylvanica | Red Ash |
| Juglans cinerea | Butternut |
| Populus deltoides | Eastern Cottonwood |
| Populus deltoides x P. grandidentata | Eastern Cottonwood x Large-toothed Aspen |
| Quercus macrocarpa | Bur Oak |
| *Robinia pseudoacacia | Black Locust |
| Salix nigra | Black Willow |
| Tilia americana | Basswood |
| Ulmus americana | White Elm |
| Ulmus rubra ? | Slippery Elm |
SHRUBS
| Alnus rugosa (incana) | Speckled Alder |
| Cornus obliqua | Silky Dogwood |
| Cornus rugosa | Round-leaved Dogwood |
| Cornus stolonifera | Red-osier Dogwood |
| Ilex verticillata | Winterberry |
| *Lonicera tatarica | Tartarian Honeysuckle |
| Myrica gale | Sweet Gale |
| Physocarpus opulifolius | Ninebark |
| *Rhamnus cathartica | Common Buckthorn |
| *Rhamnus frangula | Glossy Buckthorn |
| Rhus radicans | Poison Ivy |
| Rhus typhina | Staghorn Sumac |
| Rosa sp. | Rose sp. |
| Rubus allegheniensis | Common Blackberry |
| Rubus odoratus | Purple-flowering Raspberry |
| Salix spp. | Willow spp. |
| Sambucus canadensis | Elderberry |
| Spiraea latifolia | Broad-leaved Meadowsweet |
| Staphylea trifolia | Bladdernut Shrub |
| Toxicodendron radicans | Climbing Poison Ivy |
| Viburnum sp. | Viburnum sp. |
| Viburnum trilobum | High-bush Cranberry |
VINES
| Amphicarpaea bracteata | Hog Peanut |
| Apios tuberosa | Groundnut |
| Celastrus scandens | Bittersweet |
| Clematis virginiana | Virgin's Bower |
| *Humulus lupulus | Hops |
| Menispermum canadense | Moonseed |
| Parthenocissus quinquefolia | Virginia Creeper |
| Sicyos angulatus | One-seeded Bur Cucumber |
| Smilax herbacea | Carrion Flower |
| Vitis riparia | Riverbank Grape |
HERBACEOUS PLANTS
| *Achillea millefolium | Yarrow |
| *Agropyron repens | Couch Grass |
| Agrostis perennans | Autumn Bent Grass |
| Alisma triviale | Water Plantain |
| *Alliaria officinalis | Garlic Mustard |
| Allium canadense | Canada Onion |
| Ambrosia artemisiifolia | Common Ragweed |
| Anemone canadensis | Canada Anemone |
| Apocynum androsaemifolium | Spreading Dogbane |
| Apocynum cannabinum? | Indian Hemp? |
| *Arctium major | Burdock |
| Arisaemum triphyllum | Jack-in-the-pulpit |
| *Artemisia biennis | Biennial Wormwood |
| *Artemisia vulgaris | Common Mugwort |
| Asclepias syriaca | Common Milkweed |
| Asclepias incarnata | Swamp Milkweed |
| Aster lanceolatus | Panicled Aster |
| Aster novae-angliae | New England Aster |
| Aster umbellatus | Flat-topped Aster |
| Astragalus canadensis | Milk-vetch |
| Bidens cernua | Bur-marigold |
| Bidens frondosa | Beggarticks |
| Boehmeria cylindrica | False Nettle |
| *Butomus umbellatus | Flowering Rush |
| Calamagrostis canadensis | Canada Blue Joint |
| *Campanula rapunculoides | Creeping Bellflower |
| Cardamine pensylvanica | Pennsylvania Bittercress |
| Carex bromoides | Brome-like Sedge |
| Carex folliculata | Folliculate Sedge |
| Carex lupulina | Hop Sedge |
| Carex typhina | Cattail Sedge |
| Chelone glabra | Turtlehead |
| Chenopodium glaucum | Oak-leaved Goosefoot |
| *Chrysanthemum leucanthemum | Oxeye Daisy |
| *Cichorium intybus | Chicory |
| Cicuta bulbifera | Bulb-bearing Water Hemlock |
| Circaea quadrisulcata | Enchanter's Nightshade |
| *Cirsium arvense | Canada Thistle |
| *Cirsium vulgare | Bull Thistle |
| *Commelina communis | Asiatic Dayflower |
| Convolvulus sp. | Bindweed sp. |
| *Coronilla varia | Crown Vetch |
| Cyperus acuminatus | |
| Cyperus diandrus | Two-stamened Cyperus |
| Cyperus odoratus | Engelmann's Umbrella-sedge (incl. C. engelmanii) |
| Cyperus rivularis | River Cyperus |
| Cyperus strigosus | Strigos Cyperus |
| Danthonia spicata | Poverty Grass |
| *Daucus carota | Queen Anne's Lace |
| Desmodium canadense | Showy TickTrefoil |
| *Digitaria ischaemum | Small Crab Grass |
| Dulichium arundinaceum | Three-way Sedge |
| Echinochloa microstachya | |
| Echinochloa wiegandii | |
| Eleocharis obtusa | Blunt Spike-rush |
| Elodea canadensis | Canada Water-weed |
| Elymus virginicus | Wild Rye |
| Epilobium angustifolium | Fireweed |
| Epilobium glandulosum | Northern Willow Herb |
| Epilobium strictum | Downy Willow Herb |
| *Epipactis helleborine | Helleborine |
| Eragrostis hypnoides | Moss-like Love Grass |
| *Eragrostis minor | |
| *Eragrostis pectinacea | Pectinate Love Grass |
| Erechtites hieracifolia | Pilewort |
| Erigeron annuus | Daisy Fleabane |
| Erigeron (Conyza) canadensis | Horseweed |
| *Erysimum (cheiranthoides?) | Wormseed Mustard |
| Eupatorium maculatum | Spotted Joe-pye Weed |
| Eupatorium rugosum | White Snakeroot |
| Fimbristylis autumnalis | Autumn Fimbristylis |
| Fragaria virginiana | Wild Strawberry |
| Galium aparine | Cleavers |
| Galium obtusum | Wild Madder |
| Galium triflorum | Sweet-scented Bedstraw |
| Gerardia tenuifolia | Slender Gerardia |
| Geum sp. | Geum sp. |
| *Glechoma hederacea | Ground Ivy |
| Glyceria borealis | Northern Manna Grass |
| Glyceria striata | Fowl Manna Grass |
| Gnaphalium uliginosum | Low Cudweed |
| *Helianthus tuberosus | Jerusalem Artichoke |
| *Hydrocharis morsus-rani | European Frog-bit |
| Hypericum virginicum | Marsh St.Johnswort |
| *Hypericum perforatum | Common St. Johnswort |
| Impatiens capensis | Jewelweed |
| *Inula helenium | Elecampane |
| Iris versicolor | Larger Blue Flag |
| Junco bufonius | Toad Rush |
| Juncus effusus | Common Rush |
| Juncus filliformis | Thread Rush |
| Juncus pelocarpus | Brown-fruited Rush |
| Juncus tenuis | Slender Rush |
| Lactuca sp | Lettuce sp. |
| Laportea canadensis | Wood Nettle |
| *Lappula myosotis | Stickseed |
| *Lathyrus latifolius | Everlasting Pea |
| Lathyrus palustris | Marsh Vetchling |
| Leersia oryzoides | Rice Cut Grass |
| Leersia virginica | Cutgrass |
| Lemna minor | Lesser Duckweed |
| Lemna trisulca | Ivy-leaved Duckweed |
| *Leonurus cardiaca | Motherwort |
| *Lepidium sp. | Peppergrass sp. |
| *Linaria vulgaris | Butter-and-eggs |
| Lobelia cardinalis | Cardinal Flower |
| Lobelia inflata | Indian Tobacco |
| *Lotus corniculatus | Birdsfoot Trefoil |
| Ludwigia palustris | Marsh Purslane |
| Lycopus americanus | Cut-leaved Water-horehound |
| Lycopus uniflorus | Northern Bugleweed |
| Lysimachia ciliata | Fringed Loosestrife |
| *Lysimachia nummularia | Moneywort |
| Lysimachia terrestris | Yellow Loosestrife |
| *Lythrum salicaria | Purple Loosestrife |
| *Melilotus alba | White Sweet Clover |
| Mentha arvense | Wild Mint |
| Mimulus ringens | Monkey Flower |
| *Mollugo verticillata | Carpetweed |
| Muhlenbergia frondosa | Wirestem Muhlenbergia |
| *Myriophyllum spicatum | Spiked Water Milfoil |
| Najas flexilis | Naiad |
| *Nepeta cataria | Catnip |
| Nuphar variegatum | Yellow Pond Lily |
| Nymphaea odorata | |
| Nymphaea tuberosa | Tuberous Water Lily |
| Oenothera biennis | Common Evening Primrose |
| Oxalis europaea | Yellow Wood Sorrel |
| Panicum capillare | Old Witch Grass |
| Panicum gattinger | Gattinger's Panic Grass |
| Panicum lanuginosum | Hairy Panic Grass |
| Panicum tuckermanii | Tuckerman's Panic Grass |
| *Phalaris arundinacea | Reed Canary Grass |
| Physalis sp | |
| Pilea pumila | Clearweed |
| *Plantago major | Common Plantain |
| Poa palustris | Swamp Meadow Grass |
| Poa pratensis | Kentucky Blue Grass |
| Polygonum sp. | Polygonum sp. |
| *Polygonum aviculare | Prostrate Knotweed |
| *Polygonum cuspidatum | False Bamboo |
| *Polygonum persicaria | Lady's Thumb |
| Pontederia cordata | Pickerelweed |
| *Potentilla argentea | Silvery Cinquefoil |
| Potentilla norvegica | Rough Cinquefoil |
| Potamogeton vaseyi | Vasey's Pondweed |
| Potamogeton zosteriformis | Flat-stem Pondweed |
| *Prunella vulgaris | Selfheal |
| Ranunculus abortivus | Kidneyleaf Buttercup |
| Ranunculus pensylvanicus | Bristly Crowfoot |
| Rudbeckia hirta | Black-eyed Susan |
| *Rumex obtusifolius | Broad-leaved Dock |
| Sagittaria graminea | Grass-leaved Arrowhead |
| Sagittaria latifolia | Broad-leaved Arrowhead |
| Saponaria officinalis | Soapwort (Bouncing Bet) |
| Scirpus pedicillatus | Pedicled Bulrush |
| Scirpus pungens | |
| Scirpus validus | Strong Bulrush |
| Scutellaria galericulata | Common Skullcap |
| *Sedum acre | Mossy Stonecrop |
| *Setaria glauca | Foxtail |
| *Setaria verticillata | Bur Bristle Grass |
| *Setaria viridis | Green Foxtail |
| *Silene cucubalus | Bladder Campion |
| Sisyrinchium angustifolium | Blue-eyed Grass |
| Smilacina racemosa | False Solomon's seal |
| Smilacina stellata | Starry False Solomon's seal |
| *Solanum dulcamara | Nightshade |
| Solidago altissima | Tall Goldenrod |
| Solidago gigantea | Late Goldenrod |
| Solidago (Euthamia) graminifolia | Narrow-leaved Goldenrod |
| Solidago rugosa | Rough-stemmed Goldenrod |
| *Sonchus oleraceus | Common Sow-thistle |
| Sparganium americanum | American Bur-reed |
| Sparganium eurycarpum | Broad-fruited Bur-reed |
| Spartina pectinata | Cordgrass |
| Stachys tenuifolia | Common Hedge Nettle |
| *Taraxacum officinale | Dandelion |
| Thalictrum polygamum | Tall Meadowrue |
| *Tragopogon pratensis | Yellow Goat's-beard |
| *Trifolium dubium | Least Hop Clover |
| *Trifolium hybridum | Alsike Clover |
| Typha latifolia | Cattail |
| Urtica dioica | Stinging Nettle |
| Utricularia vulgaris | Common Bladderwort |
| Vallisneria americana | American Eel-grass |
| *Verbascum thapsus | Common Mullein |
| Verbena hastata | Blue Vervain |
| Verbena urticifolia | White Vervain |
| *Veronica peregrina | Purslane Speedwell |
| Vicia americana | American Vetch |
| Viola sp. | Violet sp. |
| Xanthium strumarium | Cocklebur |
| Zosterella dubia | Mud Plantain |
FERNS AND FERN ALLIES
| Athyrium felix-femina | Lady Fern |
| Botrychium multifidum | Leathery Grape Fern |
| Matteuccia strutheopteris | Ostrich Fern |
| Onoclea sensibilis | Sensitive Fern |
| Osmunda regalis | Royal Fern |
| Equisetum arvense | Field Horsetail |
| Equisetum hyemale | Rough Horsetail |
Regionally Significant Native Plants Found on Petrie Islands
As determined by Gillett and White 1978 [1], and Brunton 1998 [2]. The Nature Conservancy rarity code (S1, S2,S3 or S3S4) employed by the Natural Heritage Information Centre to designate a provincially rare species, as noted in Brunton 1998, is used where applicable.
| Allium canadense(1,2) | Canada Onion |
| Apios tuberosa(1) | Groundnut |
| Astragalus canadensis(1) | Canadian Milk-vetch |
| Carex folliculata(1,2)S3 | Folliculate Sedge |
| Carex typhina(1,2)S2 | Cattail Sedge |
| Celtis occidentalis(1) | Hackberry |
| Cyperus diandrus(2) | Two-stamened Cyperus |
| Cyperus odoratus(2) | Engelmann's Umbrella-sedge (incl. C. engelmannii) |
| Cyperus strigosus(1) | Strigos Cyperus |
| Dulichium arundinaceum(1) | Three-way Sedge |
| Echinochloa microstachya(2) | |
| Epilobium strictum (1,2) | Downy Willow Herb |
| Eragrostis hypnoides(1,2) | Mossy Love Grass |
| Fimbristylis autumnalis(1,2) | Autumn Fimbristylis |
| Galium aparine(1) | Cleavers |
| Galium obtusum(1,2) | Wild Madder |
| Muhlenbergia frondosa(1,2) | Wirestem Muhlenbergia |
| Panicum gattingeri(2)S3 | Gattinger's Panic Grass |
| Panicum tuckermanii(1,2) | Tuckerman's Panic Grass |
| Potamogeton vaseyi(1,2) | Vasey's Pondweed |
| Potamogeton zosteriformis(1) | Flat-stem Pondweed |
| Scirpus pedicillatus(1,2) | Pedicled Bulrush |
| Sisyrinchium angustifolium(2) | Blue-eyed Grass |
| Sparganium americanum(1,2) | American Bur-reed |
| Staphylea trifolia(1,2) | Bladdernut Shrub |
| Toxicodendron radicans(2) | Climbing Poison Ivy |
| Verbena urticifolia(1,2) | White Vervain |
| Vicia americana(1,2) | American Vetch |
| Zosterella dubia(1) | Mud Plantain |
BIRDS OF PETRIE ISLANDS
APPENDIX C.
BUTTERFLIES OF PETRIE ISLANDS
MAMMALS OF PETRIE ISLANDS
APPENDIX E.
REPTILES AND AMPHIBIANS OF PETRIE ISLANDS