1. travel
2. tourist destinations
3. canada

Assessment and Comparison of Three
Invasive Plant Species in Saskatchewan
Sarah Marshall
www.usask.ca
Outline
•
•
•
•
Background
Objectives
Approach
Assessment
SaskInvasives.ca
• Common Tansy
• Leafy Spurge
• Saltcedar
• Synthesis & Recommendations
SK Ministry of Agriculture
www.usask.ca
Background
• Invasive plants in SK can have a negative impact
on both agriculture and wildlife habitat.
• Invasive Alien Species Partnership Program
(Environment Canada, 2012).
• iMapInvasives Saskatchewan
• Saskatchewan Conservation Data Centre
• Saskatchewan Invasive Species Council
•
Fact sheets & Posters
www.usask.ca
Objectives
1. To conduct an assessment of 3 invasive plant species
in SK (common tansy, leafy spurge, saltcedar),
comparing their impact on biodiversity.
2. To provide recommendations prioritizing the
importance of control or limitation of these species,
directed at policy makers and organizations with
limited resources.
www.usask.ca
Approach
• Based on “An Invasive Species Assessment
Protocol” (Morse et al, 2004)  “I-Rank”
• Evaluation of 4 categories:
•
•
•
•
Ecological Impact
Current Distribution and Abundance
Trend in Distribution and Abundance
Management Difficulty
www.usask.ca
Common Tansy (Tanacetum vulgare)
• A perennial aster, introduced to
North America from Europe over
200 years ago.
• Common in pastures, roadsides,
and riparian areas. (McClay et al,
n.d.).
• Extensive research has been done
on the biology and control of this
herb (Gassmann et al, 2012).
©2009 Barry Breckling
www.usask.ca
Common Tansy (cont’d)
Ecological
Impact (Low)
•
•
•
•
Current D & A
(High)
Outcompetes
•
native vegetation
Reduces
productivity of
pastures
•
Hinders forest
restoration efforts
Contains toxic
compounds, but
death from
exposure is rare
(McClay et al, n.d.)
Has been
invasive in North
America for over
200 years
Currently widely
distributed
across Canada
and the United
States, from
coast to coast
(NatureServe, 2015)
Trend in D & A
(Low)
Management
Difficulty (Medium)
•
•
•
Rapid spread is
not a serious
concern
Already
occupying most
of its potential
North American
range
(NatureServe, 2015)
Can reproduce
vegetatively, limiting
mechanical control
options
• Herbicides are
effective
(NatureServe, 2015)
• Promising research
into biocontrol by
European insect
species
(McClay et al, n.d.,
Gassmann et al, 2012)
www.usask.ca
www.usask.ca
Leafy Spurge (Euphorbia esula)
• Aggressive perennial introduced to
America in the early 1800s from
Europe/Asia.
• Contains milky sap which is irritating
to the skin of both humans and
animals.
• Generalist species; Can survive in a
wide variety of habitats.
William M Ciesla, Forest Health
Management International, Bugwood.org
(Saskatchewan Invasive Species Council, n.d.)
www.usask.ca
Leafy Spurge (cont’d)
Ecological
Impact
(Medium)
Current D & A
(High)
Trend in D & A
(High)
Management
Difficulty (Medium)
•
•
•
•
•
•
•
Milky sap is
highly irritating
Grows up to
1m tall, shading
out native
species
Reduces soil
moisture and
releases toxins
Especially
severe problem
on the prairies
(NatureServe,
2015)
Found throughout
the world, including
across Canada
• Spread to > 2
million ha of the
Great Plains
• Extensive
infestation in SK
prairies
• Among 100 of the
“World’s Worst”
invaders
(ISSG, 2010)
(NatureServe, 2015)
Efficient
vegetative and
sexual
reproduction
allow for rapid
spread
• Threatening
endangered
habitats such as
tall grass prairie
(ISSG, 2010)
(iMapInvasives,
2015)
(NatureServe, 2015)
Extensive
resprouting root
system makes
mechanical control
ineffective
• Herbicides have
some success if
applied multiple
years
• Research into
biological control
underway
(ISSG, 2010)
(NatureServe, 2015)
www.usask.ca
www.usask.ca
Saltcedar (Tamarix spp.)
• Deciduous shrubs native to Asia,
introduced to the US in the 1800s
• Naturalized in western US, but
only starting to invade Canada
• Incredible reproductive capacity
(~600,000 seeds/plant/year!)
• Very damaging to natural
ecosystems
(Swift Current Creek Watershed Stewards, n.d.)
©2009 Thomas Stoughton
www.usask.ca
Saltcedar (cont’d)
Ecological Impact Current D & A
(High)
(Low)
Trend in D & A
(High)
Management
Difficulty (High)
•
•
•
Increases salinity • Prevalent in US,
of surrounding soil
just starting to
• Reduces water
invade Canada
table significantly • Most commonly
• Outcompetes
found in riparian
native vegetation
areas of arid
• Increase
ecoregions
likelihood of flood • Also among 100
and fire
of “World’s
• Changes structure
Worst” invaders
of riparian areas
(ISSG, 2010)
(NatureServe,
(ISSG, 2010)
2015)
Has now been
recorded in AB,
SK, and MB, but
still in the
beginning stages
• Seeds are easily
dispersed long
distances
• Site disturbance
increases
establishment
(iMapInvasives,
2015)
(NatureServe, 2015)
Extremely difficult to
control; almost
impossible to
eradicate
• Mechanical removal
often unsuccessful
due to root regrowth
• Herbicides can be
effective, but often
unsuitable due to
riparian habitat
• Biocontrol still being
tested
(SCCWS, n.d.)
www.usask.ca
www.usask.ca
Synthesis & Recommendations
Species
Ecological Current
Impact
D&A
Trend in
D&A
Management Overall
Difficulty
Ranking
Tansy
Low
Medium
Low
Medium
Low Medium
Spurge
Medium
High
High
High
High
Low
High
High
High
Saltcedar High
Recommended Management Actions:
•
•
•
Prioritization of leafy spurge and saltcedar over common tansy where resources are
limited
Aggressive prevention of the invasion of saltcedar into Saskatchewan
• Raising awareness, increased monitoring, inspection of vehicles travelling from
US to Canada
Further research into biocontrol methods for all three species (especially leafy spurge)
www.usask.ca
Thank you to…
• Peter Kingsmill (PWWG) & John
Kindrachuk (Redberry Biosphere
Reserve) for supervising this project.
• Ahdia Hassann (SCDC) for providing
access to iMapInvasives.
• Chet Neufeld (NPSS/SISC) for
invaluable information on
Saskatchewan invasive species.
www.usask.ca
References
•
•
•
•
•
•
•
•
Environment Canada. 2012. Invasive Alien Species Partnership Program: 2005-2010 Report. Environment
Canada, Gatineau, Quebec.
Gassmann A, Leroux A, Bennett M, Penic M, Jović J, Toševski I. 2012. Biological control of common tansy,
Tanacetum vulgare. CABI, Delémont, Switzerland.
iMapInvasives: an online data dystem supporting strategic invasive species management. 2015. NatureServe.
Available from: http://imapinvasives.org (Accessed 23 March 2015).
McClay A, Chandler M, Gassmann A, Grosskopf G, Schaffner U, Gaskin J. (n.d.). A biological control program for
common tansy (Tanacetum vulgare) in Canada and the United States. Saskatchewan Invasive Species Council.
Available from: http://www.saskinvasives.ca/file/Tansy%20poster%202008%20v2.pdf (Accessed 13 March
2015).
Morse LE, Randall JM, Benton N, Hiebert R, Lu S. 2004. An invasive species assessment protocol: evaluating
non-native plants for their impact on biodiversity. Version 1. NatureServe, Arlington, Virginia.
NatureServe. 2015. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1.
NatureServe, Arlington, Virginia. Available from: http://explorer.natureserve.org (Accessed 23 March 2015).
Saskatchewan Invasive Species Council. (n.d.). Leafy Spurge. SISC, Saskatoon, Saskatchewan. Available from:
http://www.saskinvasives.ca/ckfinder/userfiles/files/Leafy%20Spurge.pdf (Accessed 13 March 2015).
Swift Current Watershed Stewards. (n.d.). Salt Cedar: Have you seen this shrub? SCCWS, Swift Current,
Saskatchewan. Available from: http://www.saskinvasives.ca/file/Salt%20Cedar%20Fact%20Sheet[1].pdf
(Accessed 13 March 2015).
www.usask.ca