Species at Risk Act Recovery Strategy Series

Species at Risk Act Recovery Strategy Series Recovery Strategy for the Hill's Thistle (Cirsium hillii) in Canada November 2010

Recovery Strategy for the Hill's Thistle (Cirsium hillii) in Canada

Hill's Thistle



      1.3.1. Species Description
      1.3.2. Species Needs
      1.4.1. Description of Threats
      1.4.2. Limiting Factors
   1.6. Knowledge Gaps
      2.3.3. Promoting site stewardship
   2.4. Critical Habitat

About the Species at Risk Act Recovery Strategy Series

What is the Species at Risk Act (SARA)?

SARA is the Act developed by the federal government as a key contribution to the common national effort to protect and conserve species at risk in Canada. SARA came into force in 2003, and one of its purposes is "to provide for the recovery of wildlife species that are extirpated, endangered or threatened as a result of human activity."

What is recovery?

In the context of species at risk conservation, recovery is the process by which the decline of an endangered, threatened, or extirpated species is arrested or reversed and threats are removed or reduced to improve the likelihood of the species' persistence in the wild. A species will be considered recovered when its long-term persistence in the wild has been secured.

What is recovery strategy?

A recovery strategy is a planning document that identifies what needs to be done to arrest or reverse the decline of a species. It sets goals and objectives and identifies the main areas of activities to be undertaken. Detailed planning is done at the action plan stage.

Recovery strategy development is a commitment of all provinces and territories and of three federal agencies - Environment Canada, Parks Canada Agency, and Fisheries and Oceans Canada - under the Accord for the Protection of Species at Risk. Sections 37-46 of SARA (http://www.sararegistry.gc.ca/approach/act/default_e.cfm) outline both the required content and the process for developing recovery strategies published in this series.

Depending on the status of the species and when it was assessed, a recovery strategy has to be developed within one to two years after the species is added to the List of Wildlife Species at Risk. Three to four years is allowed for those species that were automatically listed when SARA came into force.

What's next?

In most cases, one or more action plans will be developed to define and guide implementation of the recovery strategy. Nevertheless, directions set in the recovery strategy are sufficient to begin involving communities, land users, and conservationists in recovery implementation. Cost-effective measures to prevent the reduction or loss of the species should not be postponed for lack of full scientific certainty.

The series

This series presents the recovery strategies prepared or adopted by the federal government under SARA. New documents will be added regularly as species get listed and as strategies are updated.

To learn more

To learn more about the Species at Risk Act and recovery initiatives, please consult the SARA Public Registry.



Recovery Strategy for Hill's Thistle (Cirsium hillii) in Canada




Recommended citation:

Parks Canada Agency. 2011. Recovery Strategy for Hill's Thistle (Cirsium hillii) in Canada. Species at Risk Act Recovery Strategy Series. Parks Canada Agency. Ottawa. viii + 84 pp.

Additional copies:

Additional copies can be downloaded from the SARA Public Registry.

Cover illustration:

Hill's Thistle at Lyal Island, by Jarmo Jalava

Également disponible en français sous le titre:
« French document title »

© Her Majesty the Queen in Right of Canada, represented by the Minister of the Environment, 2008. All rights reserved.
ISBN: 978-1-100-17325-2
no.: En3-4/87-2011E-PDF

Content (excluding the illustrations) may be used without permission, with appropriate credit to the source.



The Parks Canada Agency led the development of this federal recovery strategy, working together with the other competent minister(s) for this species under the Species at Risk Act. The Chief Executive Officer, upon recommendation of the relevant Park Superintendent(s) and Field Unit Superintendent(s), hereby approves this document indicating that Species at Risk Act requirements related to recovery strategy development (sections 37-42) have been fulfilled in accordance with the Act.



All competent ministers have approved posting of this recovery strategy on the Species at Risk Public Registry.



Under the Accord for the Protection of Species at Risk (1996), the federal, provincial, and territorial governments agreed to work together on legislation, programs, and policies to protect wildlife species at risk throughout Canada. The Species at Risk Act (S.C. 2002, c.29) (SARA) requires that federal competent ministers prepare recovery strategies for listed Extirpated, Endangered and Threatened species.

The Minister of the Environment presents this document as the recovery strategy for the Hill's Thistle as required under SARA. It has been prepared in cooperation with the jurisdictions responsible for the species, as described in the Preface. The Minister invites other jurisdictions and organizations that may be involved in recovering the species to use this recovery strategy as advice to guide their actions.

The goals, objectives and recovery approaches identified in the strategy are based on the best existing knowledge and are subject to modifications resulting from new findings and revised objectives.

This recovery strategy will be the basis for one or more action plans that will provide further details regarding measures to be taken to support protection and recovery of the species. Success in the recovery of this species depends on the commitment and cooperation of many different constituencies that will be involved in implementing the actions identified in this strategy. In the spirit of the Accord for the Protection of Species at Risk, all Canadians are invited to join in supporting and implementing this strategy for the benefit of the species and of Canadian society as a whole. The Minister of the Environment will report on progress within five years.


Parks Canada Agency led the development of the recovery strategy. The strategy was prepared by J.A. Jones for the Bruce Peninsula and Manitoulin Island Alvar1 Recovery Team. Thank you to all the members of the Recovery Team for their participation in this report, with a special acknowledgement to Jarmo Jalava (Consulting Ecologist, Paisley, Ontario) for providing Bruce Peninsula data and for extensive help with the document. Consultation with First Nations on the draft recovery strategy was led by Kim Borg and Aimee Johnson (Parks Canada), and the input from Walpole Island First Nation is greatly appreciated. Clint Jacobs and Jared Macbeth of Walpole Island First Nation were most helpful in providing comments on the draft recovery strategy, and also provided the textual references on Traditional Ecological Knowledge. Brian Hutchinson and Hilary Gignac are thanked as past co-chairs of the Recovery Team from 2001 to 2005, as is Kirsten Querbach for chairing from 2005 to 2009. Thanks are also due to those who participated in the crafting of the critical habitat maps for the Bruce Peninsula, Wasaga Beach Provincial Park, and Manitoulin Region during two workshops in October 2009 and April 2010: Mark Carabetta (Ontario Nature), John Gerrath (Nature Conservancy of Canada), Bob Barnett (Escarpment Biosphere Conservancy), Anthony Chegahno (Chippewas of Nawash (Neyaashiinigmiig) First Nation), Will Kershaw (Ontario Parks), Eric Cobb (Ontario Ministry of Natural Resources), Jarmo Jalava, and Judith Jones. Mapping of the critical habitat at Wasaga Beach was only possible because of the kind provision of data by Keith Johnston and Marilyn Beecroft (Ontario Parks) and Burke Korol and Paul Jurjans (Ontario Ministry of Natural Resources). Access to the Natural Heritage Information Centre (NHIC) data, also for the purposes of the critical habitat mapping, was facilitated by Mike Oldham, Simon Dodsworth, and Martina Furrer.

1 "Alvar" is a Swedish word, originally used for the grasslands on the islands of Öland and Göteland in the Baltic Sea. In the Great Lakes basin, "alvar" refers to naturally open areas with shallow soils over relatively flat, limestone bedrock, with trees absent or at least not forming a continuous canopy (Reschke et al. 1999, Brownell and Riley 2000). There are several different kinds of alvars (just as there are different kinds of forests), and each type has a distinctive group of species present.


A strategic environmental assessment (SEA) is conducted on all Species at Risk Act recovery strategies, in accordance with the Cabinet Directive on the Environmental Assessment of Policy, Plan and Program Proposals (2004). The purpose of a SEA is to incorporate environmental considerations into the development of public policies, plans, and program proposals to support environmentally sound decision-making.

Recovery planning is intended to benefit species at risk and biodiversity in general. However, it is recognized that strategies may also inadvertently lead to environmental effects beyond their intended benefits. Environmental effects, including impacts to non-target species and the environment, were considered during recovery planning, and the results of this evaluation are discussed further in Appendix A: Effects on Other Species and the Environment.

The implementation of this recovery strategy is not expected to have any negative effects on the environment or on non-target species, and in fact is expected to benefit many other species found in the same habitat. However, researchers carrying out field studies, and those conducting monitoring in alvar habitat, need to be cautioned on the potential problem of trampling from their foot traffic, and instructed how to prevent creating such impacts. Whether controlled burning is required to maintain and improve habitat is an important knowledge gap. If burning is found to be a necessary tool for recovery, then an additional SEA would need to be done on this action. This is addressed in Section 1.6 Knowledge Gaps.


This Recovery Strategy addresses the recovery of Hill's Thistle. In Canada, this species is found only in Ontario: on Manitoulin Island and surrounding islands, on the Bruce Peninsula, and at Wasaga Beach Provincial Park (Simcoe County).

The Parks Canada Agency, the Ontario Ministry of Natural Resources, and the Canadian Wildlife Service - Ontario Region, worked in cooperation to develop this recovery strategy, with the members of the Bruce Peninsula and Manitoulin Island Alvar Recovery Team, and in cooperation and consultation with stakeholders, and private landowners. All responsible jurisdictions reviewed and supported posting of the strategy. The proposed recovery strategy meets SARA requirements in terms of content and process (Sections 39-41) and fulfills commitments of all jurisdictions for recovery planning under the Accord for the Protection of Species at Risk in Canada.


SARA defines residence as: a dwelling-place, such as a den, nest or other similar area or place, that is occupied or habitually occupied by one or more individuals during all or part of their life cycles, including breeding, rearing, staging, wintering, feeding or hibernating [Subs. 2(1)]. The concept of residence under the Species at Risk Act (SARA) does not apply to this species.Residence descriptions, or the rationale for why the residence concept does not apply to a given species, are posted on the SARA registry.


Recovery of Hill's Thistle in Canada is considered feasible based on the criteria outlined by the Government of Canada (2009).

  1. Individuals of the wildlife species that are capable of reproduction are available now or in the foreseeable future to sustain the population or improve its abundance.
    There are several natural, large, actively reproducing populations of Hill's Thistle in locations with large areas of suitable habitat. This suggests that individuals are capable of reproducing at a rate sufficient to maintain and improve population sizes.

  2. Sufficient suitable habitat is available to support the species or could be made available through habitat management or restoration.
    One of the main threats to Hill's Thistle is filling in of habitat, likely due to fire suppression. However, the most recent burning (at least for habitat in the Bruce Peninsula and Manitoulin Island regions) took place 100 or more years ago, so encroachment is a very slow process. In addition, although habitat patch sizes are shrinking, there are still a large number of sites. Therefore, there is enough habitat which can be restored or improved, and enough time to plan and implement management and restoration actions.

    Reinstating intense, catastrophic wildfire into the human landscape in order to recover Hill's Thistle habitat would be a very difficult thing to do; however, other methods of maintaining existing habitat (e.g. low-level burning, cutting and clearing) may prove effective. This option still needs to be researched.

  3. The primary threats to the species or its habitat (including threats outside Canada) can be avoided or mitigated.
    Many threats can be avoided or mitigated through communications actions to increase awareness about the species, liaising with other groups and agencies, erecting signage, working with management of protected areas, and many other steps.

  4. Recovery techniques exist to achieve the population and distribution objectives or can be expected to be developed within a reasonable timeframe.
    The Nature Conservancy's International Alvar Initiative (IACI) (Reschke et al. 1999) initiated recovery of alvar ecosystems and associated rare species using several of the steps that are now suggested here for Hill's Thistle, and experiences from the IACI show these techniques can be very effective.


Hill's Thistle (Cirsium hillii) is listed as Threatened under Schedule 1 of the federal Species at Risk Act (SARA). In Ontario, it is listed as Threatened on the Species at Risk in Ontario (SARO) List under the Endangered Species Act, 2007 (ESA). The global rank of Hill's Thistle is vulnerable, and is completely restricted to the Great Lakes Region. The Canadian range of Hill's Thistle may account for as much as 50% or more of the global population.

Hill's Thistle is a perennial with a deep tap root or a cluster of roots with tuberous swellings. The leaf margins and flower heads are spiny. The plants live as sterile rosettes for the first two to several years, until they produce an upright stem with a single, large flower head. After flowering and setting seed, the plants die. In Canada, Hill's Thistle is only found in the Manitoulin Region, on the Bruce Peninsula, and at Wasaga Beach Provincial Park (Simcoe County). There are 93 known sites and upwards of 13,000 individuals.

This species requires dry, open, grassy ground with little canopy cover. The required habitat can be found within several different vegetation types including prairies, sand barrens, oak and jack pine savannas, alvars, openings in woodlands, and behind dunes.

Some habitat for Hill's Thistle probably originates from fire, but there is little evidence to suggest that repeat burning after the initial fire at these sites has occurred. Hill's Thistle often occurs in areas of historic-era disturbance; however, in Canada today Hill's Thistle is never found in recently disturbed areas. In marginally suitable habitat, a trail may provide habitat where there is no other open ground, but in high quality habitat, anthropogenic disturbance may be detrimental and is not recommended as a management tool at this time. Threshold levels at which disturbance becomes harmful have not been determined.

Limited habitat is the primary threat to Hill's Thistle. The limitation may be due to filling in of habitat due to fire suppression or loss of habitat from development (building and road construction). Other threats include heavy machinery use for ornamental stone removal and logging, trampling by pedestrians or mountain bikes, and indiscriminate use of all-terrain vehicles.

Recovery is considered feasible for Hill's Thistle. The goal is to maintain, over the long-term, self-sustaining populations of Hill's Thistle in its current range in Canada, by meeting population and distribution objectives targeted to recover the species to Special Concern or lower. The population and distribution objectives for Hill's Thistle are: 1) No continuing decline in total number of mature individuals, and 2) Populations are maintained in the four core areas the species occupies.

Critical habitat has been identified and mapped for 90 polygons at 17 sites on the Bruce Peninsula, at Wasaga Beach, and in the Manitoulin Region, and will contribute significantly to the recovery objectives. Other recovery tools will be used to meet the objectives, and these will be achieved through implementation of a suite of broad strategies and approaches.

One or more action plans will be developed by December 2015.

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