Scientific Name: Baccharis halimifolia
Taxonomy Group: Vascular Plants
COSEWIC Range: Nova Scotia
COSEWIC Assessment Date and Status Change: November 2011
COSEWIC Status: Threatened
COSEWIC Status Criteria: D2
COSEWIC Reason for Designation:
The species is an Atlantic Coastal Plain Flora species. A rare Canadian disjunct shrub restricted to very specific salt marsh habitat in southern Nova Scotia. Its coastal habitat is declining due to increasing shoreline development. Further, climate change effects, including rising sea level and increasing and more frequent storm surges, will cause habitat loss and degradation as well as impact individuals over the next few decades.
COSEWIC History of Status Designation: Designated Threatened in November 2011.
SARA Status: Schedule 1, Threatened
Date of Listing (yyyy-mm-dd): 2017-06-02
Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.
Eastern Baccharis is a perennial, salt marsh shrub of the Aster family. In Canada, it is 1 to 3 metres tall and deciduous with alternate gray-green leaves. Male and female flowers occur on different plants. It blooms in late summer with inflorescences of tiny flowers that can be very numerous on larger shrubs. The brilliant white pappus (bristles) on the seeds makes female plants easy to detect in late summer and early fall. In Canada, Eastern Baccharis is rare, localized and 400+ km disjunct from the next nearest occurrence in northern Massachusetts. Eastern Baccharis is the only native representative of its genus and subtribe in Canada. The species is used horticulturally in the United States. Baccharis species contain an array of chemicals used medicinally, including some with potential for cancer treatment, but formal investigation of their properties has been limited. American First Nations have used some species in the treatment of sores and wounds, and as antibacterials and emetics. Eastern Baccharis has been introduced to and has become a problematic invasive in Mediterranean Europe and Australia and it is an agricultural weed in some U.S. states. [Updated by COSEWIC - Nov. 2011]
Distribution and Population
Eastern Baccharis is native along the Gulf of Mexico south to Veracruz, Mexico and along the United States east coast north to northern Massachusetts. Southward, it occurs inland to Oklahoma, Arkansas, Tennessee and the Piedmont east of the Appalachians, although some of this distribution represents post-European colonization. It is also native in Cuba and the Bahamas. Canadian occurrences are restricted to a 25 km stretch of coast in extreme southwestern Nova Scotia. Populations are dominated by large, mature individuals, suggesting long-term occurrence in Nova Scotia. The total number of mature individuals in Canada is estimated at 2850 and is probably quite completely documented. Three populations are known, with an additional site (West Pubnico) having only one known individual. These populations are divided into 9 subpopulations, two of which support ~88% of the Canadian population. Population trends are not documented but are likely fairly stable. Only relatively small and localized development impacts have thus far occurred, but development is active or imminent in some populations and a future threat in others. [Updated by COSEWIC - Nov. 2011]
In the U.S., Eastern Baccharis occurs in a variety of moist or disturbed habitats. In Canada, it is restricted to open margins of well-developed salt marshes within harbours or bays that provide protection from wind and waves. It occurs in or near the transition zone to coastal forest with predominantly graminoid vegetation and shrubs 0.5 m to 2 m in height. Climate likely limits its extent of occurrence. Oceanic currents moderate the climate of the coastal zone of southwestern Nova Scotia, especially the area around Yarmouth where Eastern Baccharis occurs, the warmest Canadian winters outside of southern British Columbia, with temperatures considerably milder than the coast of Maine at the same latitude. [Updated by COSEWIC - Nov. 2011]
In Nova Scotia, Eastern Baccharis flowers from late July through mid- or late September. Females can produce more than one million seeds. Mature achenes (fruits) are wind- and water-dispersed, aided by the attached pappus. Achenes mature in late August or September, with most having dispersed by late October. In Nova Scotia (but not in the southern U.S.), leaves are deciduous in late October and November, later than most associated shrubs. Seedlings in Nova Scotia have been observed very infrequently, suggesting establishment from seed is uncommon. Large individuals in Nova Scotia can have trunks up to about 10 cm diameter, suggesting considerable age, and new shoots sprout from the bases of mature shrubs, suggesting that individuals could persist for decades or longer. Eastern Baccharis also spreads vegetatively via the rooting of low branches. Seed banking is likely not significant because seeds have limited dormancy, but seeds can survive a minimum of two years if buried. [Updated by COSEWIC - Nov. 2011]
Habitat loss from coastal development, primarily for cottages or residences, is the only imminent threat. Development has been extensive on Nova Scotia’s Atlantic coast in the past 30 years, causing vast increases in land values. Eastern Baccharis occurs in aesthetically attractive coastal habitats and most occurrences are within a few hundred metres of good roads. Its habitat along the margin of coastal forest makes it especially prone to clearance by landowners seeking water views or access. It is, however, somewhat protected from development in many sites, including the two large subpopulations, because it occurs on islands within salt marshes for which creating road access would be expensive or against environmental regulations. Death of individual plants from apparent saltwater inundation was observed very locally and habitat loss from sea level rise may be a future threat. Localized impacts from cattle grazing were also observed at one site. The extreme concentration of the population (~88% of total) into two dense areas of occurrence totaling 11.5 ha means that development, sea level rise or chance events in those areas could substantially reduce the entire Canadian population. Observations suggesting limited recruitment from seed increase the significance of any threat that would remove mature individuals. [Updated by COSEWIC - Nov. 2011]
The Eastern Baccharis is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
Provincial and Territorial Protection
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
9 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- Response Statements (1 record(s) found.)
- Recovery Strategies (1 record(s) found.)
- Action Plans (1 record(s) found.)
- Orders (2 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
- Consultation Documents (1 record(s) found.)
- Related Information (1 record(s) found.)
COSEWIC Status Reports
Response Statement - Eastern Baccharis (2013-01-03)The species is an Atlantic Coastal Plain Flora species. A rare Canadian disjunct shrub restricted to very specific salt marsh habitat in southern Nova Scotia. Its coastal habitat is declining due to increasing shoreline development. Further, climate change effects, including rising sea level and increasing and more frequent storm surges, will cause habitat loss and degradation as well as impact individuals over the next few decades.
COSEWIC Annual Reports
COSEWIC Annual Report - 2011-2012 (2012-10-05)Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings in this reporting year (September 1, 2011 to September 30, 2012) from November 21 to 25, 2011 and from April 29 to May 4, 2012. On February 3, 2012, an Emergency Assessment Subcommittee of COSEWIC also assessed the status of the Tri-colored Bat (Perimyotis subflavus), the Little Brown Myotis (Myotis lucifugus), and the Northern Myotis (Myotis septentrionalis). During the current reporting period COSEWIC assessed the status or reviewed the classification of 67 wildlife species. For species already found on Schedule 1 of SARA, the classification of 32 species was reviewed by COSEWIC and the status of the wildlife species was confirmed to be in the same category (extirpated - no longer found in the wild in Canada but occurring elsewhere, endangered, threatened or of special concern). The wildlife species assessment results for the 2011-2012 reporting period include the following: Extinct: 1 Extirpated: 4 Endangered: 29 Threatened: 10 Special Concern: 15 Data Deficient: 2 Not at Risk: 6 Total: 67 Of the 67 wildlife species examined, COSEWIC reviewed the classification of 49 species that had been previously assessed. The review of classification for 26 of those species resulted in a confirmation of the same status as the previous assessment (see Table 1a).