Recovery Strategy for the Hill's Thistle in Canada [Final Version] 2011: Appendix A
Recovery efforts for Hill's Thistle are not expected to have adverse effects on other species; however, the use of controlled burns as a habitat improvement tool must be studied before any potential effects of this can be fully determined. As discussed in Section 1.3.2, burning may be needed to create suitable habitat but could also destroy Hill's Thistle (where it already exists) and possibly other species, particularly invertebrates. Whether burning is necessary is a knowledge gap.
Mechanical removal of shrubbery, if found to be useful, might have a local, adverse effect on common early successional species such as Common Juniper, Balsam Poplar (Populus balsamifera), Staghorn Sumac (Rhus typhina), or Green Ash (Fraxinus pennsylvanica) if these species were removed. However, the loss of individuals of these widespread, generalist species from a small area of habitat is not considered a long-term adverse effect.
On the other hand, maintenance of open grassland through mechanical or other methods is expected to have a beneficial effect on many other species that are restricted to open grassland habitat. While many of these species are not yet at risk, they are much less common than the shrubs mentioned above, and they face the same problem of habitat loss from succession that Hill's Thistle faces. Therefore, although there may be some local loss of individuals of common woody species, the overall benefit to more uncommon species requiring open habitats is considered to outweigh the loss.
In addition, the open grassland vegetation type is itself considered rare. Naturally open habitats with good quality native vegetation, such as alvars, prairies and sand barrens, are dwindling both due to lack of wild fire (or other ecological processes) and due to conversion of these places to human uses. The overall natural landscape of Southern Ontario is forested, and naturally open habitats are the exception to the norm. Thus, maintaining open grassland will benefit less common elements of Ontario's biodiversity.
All other recovery steps are likely to help other species as they mostly deal with protecting habitat and outreach to landowners.
(includes ownership, most recent observation, estimated # of plants, & # of critical habitat polygons identified in this report). Details on recent observations are available in the databases of Bruce Peninsula National Park and the Natural Heritage Information Centre. Polygons are shown below in figures 7 to 53.
Site Name | Ownership | Most recent observation | Estimated # of Plants | # CH polygons |
---|---|---|---|---|
Wasaga Beach | Provincial Park | White 2007 | 618 in 28 plots | 12 |
Total Simcoe County: 1 site | ~700 individuals; | 12 critical habitat polygons | ||
BRUCE PENINSULA | ||||
Baptist Harbour/Cape-Hurd ANSI | Private/NGO | Jalava & Chegahno 2008; Jalava 2003 | ~50 | 3 |
Barney Lake Alvar | Private | Schaefer 1996 | 60 | |
Black Creek Provincial Park | Provincial Park | Johnson 2003 | 43 | |
Bradley Harbour | Private/County Forest | Johnson & Goodban 2001 | 75 | |
Brinkman's Creek Uplands | National Park | Brinker 2006 Jalava 2004 | 8 | 1 |
Bruce Alvar Preserve Brinkman's Corners |
NGO | Wilson 2007 | 8 | |
Corisande Bay Trail N of Scugog Lake Rover Property |
Municipal/ National Park/ Private |
Jalava 2007 Wilson 2007 |
223 | 3 |
Johnson's Harbour Rd Crane River Townline |
Private/Crown managed by BPNP | Jalava 2007 Wilson 2007 |
~30 | |
Dorcas Bay - Singing Sands Dorcas Bay Road North |
National Park | Jalava, Jones & Allen 2009 | 556 | 3 |
Eagle Road at Eagle Harbour William Henry Marsh |
Municipal/ National Park |
Jalava & Chegahno 2008; Jalava 2007 |
~97 in several subpop-ulations | 4 |
Garden Island Stokes Bay |
Private | Jalava 2005 | 83 | |
Hay Bay Road | Municipal/ claimed by F.N. | Jalava 2009 | 28 | |
Johnson Harbour - Pine Tree Point | Private/ Provincial Park | Jalava 2007 Brinker 2006 |
50 | 6 |
Ladyslipper Bay Unnamed Lake Pine Tree Point Trail |
Private | Wilson 2007 | No info | 4 |
Little Eagle Harbour | Private/ Municipal |
Brinker 2006 Jalava 2005 |
~60 | 4 |
Lyal Island | NGO | Jalava 2006 | 183 | 1 |
Oliphant South | Private | Johnson 1985 | 19 | No location data |
Pendall Lake Alvar | National Park | Brinker 2006 | 6 | 1 |
Pike Bay Alvar Whiskey Harbour Road |
Private | Allen 2002 Schaefer 1995 |
31 | |
Saugeen First Nation EO #1 | First Nation | Jalava & Root 2008 Schaefer 1996 |
196 | |
Saugeen First Nation EO #2 | First Nation | Jalava & Root 2008 | 2017 | |
Sauble Beach Walker's Woods |
Conservation Authority | Jalava 2008 | 20 | |
Scugog Lake Alvar | National Park | Jalava 2007 Brinker 2006 Schaefer 1996 |
3 | 2 |
Sideroad Creek Alvar Dorcas Bay Road South and East |
National Park | Jalava 2007 Brinker 2006 |
8 | |
Sucker Creek St. Jean's Point |
Private/ Conservation Authority | Jalava 2006 Johnson 2003 |
62 | |
Zinkan Island Cove Little Pine Tree Harbour Harkins Harbour |
Private/ Municipal | Jalava & Chegahno 2008; Jones 2008 |
~20 | |
Total Bruce Peninsula: 29 sites | >4100 individuals; | 40 critical habitat polygons | ||
ISLANDS SURROUNDING MANITOULIN ISLAND | ||||
Amedroz Island | Crown /First Nation | Jones 2008 | 85 | |
Cockburn Island North of Hershell Island |
Private/ Municipal | Morton & Venn 1977 | No info | |
Cockburn Island Wagosh Bay |
Crown | Crins 2008 | 55 | 2 |
Darch Island | Crown / First Nation |
Jones 2008 Jones 2004 |
2 | |
Fitzwilliam Island Indian Harbour |
Municipal | Jones 2008 | 5 | |
Fitzwilliam Island Phoebe Point |
Municipal | Jones 2008 | 2 | |
Fitzwilliam Island Wild Bight |
Municipal/Private | Morton & Venn 1975 | No info | |
Great Cloche Island Bell Rocks |
Corporate | Allen 2002 Jones 1996 |
37 | |
Great Cloche Island NW of Lewis Lake |
Corporate | Jones 1996 | Info missing | |
Great Cloche Island West end track |
Corporate | Jones 1996 | No info | |
Greene Island | Crown | Jones 2005 | 52 | 2 |
Innes Island | Crown/ First Nation | Jones 2004 | 39 | |
La Cloche Peninsula Dreamer's Rock |
First Nation | Morton & Venn 1978 | No info | |
Little La Cloche Island | Corporate | Allen 2002 | 157 | |
Vidal Island | Crown/First Nation | Jones 2005 | 12 | |
West Rous Island | Crown/First Nation | Jones 2004 | 36 | |
Western Duck Island | Crown | Jones 2009 | 10 | 2 |
Wikwemikong Island #1 | Crown/First Nation | Jones and Wikwem-ikong Crew 2008 | 408 | |
Wikwemikong Island #2s | Crown/First Nation | Jones and Wikwem-ikong Crew 2008 | 455 | |
Total Islands: 20 sites | >1380 individuals | 6 critical habitat polygons | ||
MANITOULIN ISLAND | ||||
Belanger Bay | Provincial Park | Jones & Hall 2009 | 96 | 8 |
Big Bay, east side | Municipal | Jones 2008 | ~62 | |
Birch Point | Private | Jones 2006 | 5 | |
Burnt Island Harbour | Provincial Park | Jones 2007 | 30 | 5 |
Carroll Wood Bay | Private | Jones 2004 | 92 | |
Christina Bay/ Burnt Island Road |
Provincial Park, Crown | Jones 2009 Allen 2002 |
24 | 2 |
Evansville Shrub Alvar | Private | Jones 1996 | 70 | |
North of Fisher Bay | Private | Jones 2005 | 88 | |
Leask Point | Private | Jones 2000 | 13 | |
West of Lynn Point | Corporate | Jones & Hall 1995 | 57 | |
Mac's Bay Alvar | Private/ Crown | Jones 2000 | 121 | 2 |
Marsh Lake Alvar | Private | Jones 2003 | 10 | |
Michael's Bay Hammond Point |
Private | Jones 2006 Oldham 1994 |
35 | |
Michael's Bay E of Manitou River Blue Jay Creek mouth |
Private | Jones 2009 Jones 2008 |
38 | |
Michael's Peninsula | Municipal | Jones 2008 | 642 | |
Misery Bay East | Provincial Park | Jones 2000 | 504 | 7 |
Misery Bay West | Provincial Park/ Private |
Jones 2000 | >100 (40 in park) |
1 |
Murphy Point | Private | Jones 2008 | No info | |
Portage Bay west side | Private | Jones 2005 | 11 | |
Portage Lake Dunes | Private | Ringius 1976 | No info | |
Providence Bay | Private | Morton & Venn 1982 | No info | |
Quarry Bay | Provincial Park/ NGO | Jones 2000 | 107 | 6 |
Sand Bay | Private | Allen 2002 | 12 | |
NW of Shrigley Bay | Private | Jones 2005 | 68 | |
SW of Silver Lake | Provincial Park | Jones 2005 | 114 | 1 |
NW of South Baymouth | Private | Morton 1997 | No info | |
West of South Baymouth Alvar | Private | Jones 2008 | 76 | |
Table Rock Flatlands | Private | Jones 2003 Noble 1995 |
61 | |
Taskerville | Private | Jones 2009 Jones 1996 |
>1000 | |
Wikwemikong EO #1 | First Nation | Jones & Wiky Crew 2007 | 175 | |
Wikwemikong EO #2 | First Nation | Jones & Wiky Crew 2007 | 308 | |
Wikwemikong EO #3 | First Nation | Jones & Wiky Crew 2007 | 169 | |
Wikwemikong EO #4 | First Nation | Jones & Wiky Crew 2007 | 261 | |
Wikwemikong EO #5 | First Nation | Jones & Wiky Crew 2007 | 20? | |
Wikwemikong EO #6 | First Nation | Jones & Wiky Crew 2007 | 78 | |
Wikwemikong EO #7 | First Nation | Jones & Wiky Crew 2007 | 31 | |
Wikwemikong EO #8 | First Nation | Jones & Wiky Crew 2007 | 147 | |
Wikwemikong EO #9 | First Nation | Jones & Wiky Crew 2007 | >2000 | |
Wikwemikong EO #10 | First Nation | Jones & Wiky Crew 2007 | 1 | |
Wikwemikong EO #11 | First Nation | Jones & Wiky Crew 2007 | 20 | |
Wikwemikong EO #12 | First Nation | Jones & Wiky Crew 2007 | 69 | |
Wikwemikong EO #13 | First Nation | Jones & Wiky Crew 2007 | 41 | |
Wikwemikong EO #14 | First Nation | Jones & Wiky Crew 2007 | 7 | |
Total Manitoulin Island: 43 sites | >6800 individuals | >32 critical habitat polygons | ||
TOTAL CANADIAN RANGE: 93 sites | >13,000 individuals | 90 critical habitat polygons |
Jones (2006) revisited several sites on Manitoulin Island that had historic records for Hill's Thistle that had not been reconfirmed for 10-30 years. She found five sites no longer supported the species. In Michigan, Voss (1996) noted that although there were a number of old records from the southern part of the state, Hill's Thistle might now be extirpated in that area.
COSEWIC (2004) lists six historically known populations, which were considered probably extirpated and several that were considered erroneous. However, some of these populations were investigated and recently relocated (Jalava 2005, 2007, 2008b, pers. comm.). Based on the most recent survey work, sites where Hill's Thistle is in fact no longer present, or has not been found in more than 20 years, are listed below.
Site Name | Last Observer* | Recent Search | Comments |
---|---|---|---|
Barrie Island: Beer Point |
Ringius & Wilson, 1976; | Not found by Jones, 2006 | Habitat is overgrown with small cedars |
Bear's Rump Island | Morton and Venn, 1987 | Not found by Jalava, 2007 or Schaefer, 1996 | |
Cape Croker/Nawash FN | Varga 1995 referring to a 'pre-1949 record' | Not found by Jalava & Chegano, 2008 | Extirpated or erroneous record |
Clapperton Island: Beattie Bay | Morton and Venn, 1976 | Not found by Jones, 2005, 2006 | Habitat present; species not found |
Clapperton Island: Logan Bay | Morton and Venn, 1976 | Not found by Jones 2005, 2006 | Habitat present; species not found |
Driftwood Cove Alvar | Schaefer, 1996 | Not found by Jalava, 2007 | Extirpated or erroneous record |
Foxy Prairie: Gore Bay Airport | J.K. Morton, 2005 | Not found by Jones 2005, 2006 | Habitat very degraded |
Roberts Bay | Morton and Venn, 1981 | Not found by Jones, 2006 | Habitat destroyed by new roads |
Sauble Beach South | J. Johnson, 1980s | General area visited by Jalava, 2008b | Area is subdivided with cottages; no habitat found |
Vidal Bay: Creasor Bight | Ringius and Wilson, 1976 | Not found by Jones 1997, 2005 | Very little habitat present; mostly overgrown |
Walpole Island F.N.: Squirrel Island | Dodge, 1914 | Not found by Gaiser, 1966; or Woodliffe and Allen, 1988 | |
Wasaga Beach: Nottawasaga Bay Shore | A.A. Reznicek 1970s | Believed extirpated by recreational development (COSEWIC, 2004) |
* Information from Morton and Venn, 2000; COSEWIC, 2004; Jalava, 2008a,b; and Joan Venn, pers. comm.
Page details
- Date modified: