1. Tamarisk Control
on the Colorado River
Justin Beckett, Connor Lambert, Jesse Morris, & Brandon White

2. Background
A shrub like tree
scale-like leaves
deciduous foliage
spreads by seed and
adventitious roots
grows along riparian
areas

3. Background
Native across Europe and Asia
Introduced in the 1800’s for shade, windbreak,
ornamental
Escaped cultivation
Primarily occurs in the Southwest US
became a dominant species along the
Colorado River in 1963

5. Why Control it?
Competitive advantages include:
can use unsaturated soil water
high transpiration rates
alters soil salinity
can tolerate an extreme range of conditions

6. Forms monocultures
Displaces native vegetation
changes wildlife habitat

7. General Goals and Objectives
Restore riparian areas
Improve ecological
function
Improve wildlife habitat
Increase water yield

8. Specific Goals and Objectives
Reduce Tamarisk
cover/abundance
Reduce fuel loads
Increase biological
diversity
Increase native species’
cover/richness

9. Considerations
Time
Reseeding
Soil salinity
Water table
Cost

10. Environmental Concerns
● unfortunately, salt cedar infests
riparian areas- habitat that is very
sensitive and vulnerable

11. Treatments Overview
-Herbicide
-Mechanical
-Biological
-Fire

12. Herbicide: 3 Methods
Method 1: Broadcast
Method 2: Cutting
Method 3: Plowing
Image Courtesy of www.tractorbuynet.com

13. Herbicides
triclopyr- low toxicity to most animals- but may
affect ducks, quails, trout
tebuthiuron- may contaminate groundwater, kill
fish
hexazinone- contaminates groundwater, non-
selective
imazapyr- soil active, non-selective

14. Mechanical
-Cutting
-Shredding
-Chaining
-Discing
-Mowing
Problem:
Tamarisk sprouts
back, so if done alone
mechanical
treatments are not
very effective.

15. Fire
-Clears the ground,
reduces fuels and
competition
-Induces tamarisk
sprouting
Photo Courtesy of www.fs.fed.us

16. Mechanical & Fire
Most mechanical treatments still
requires burning/herbicide
Burning- all problems usually
associated with it- may be harder
to burn in wetter areas
erosion!
Rapid changes to aquatic
ecosystems

17. The Bea[e]tles!!
The northern tamarisk beetle-
unknown if any negative ecological
effects
can be very successful
•Stage 1: Egg
•Stage 2: Larvae
•Stage 3: Pupa (on the ground)
•Stage 4: Immerge as adults
•Stage 5: Diapause

18. So bad… it’s good?
Tamarisk has taken over areas in the Grand
Canyon so extensively, it is prime nesting
habitat
the tamarisk beetle has defoliated and killed
acres upon acres
Southwestern Willow Flycatcher
Endangered Species Act- the greater good?
has tamarisk become habitat for other species?

19. The Plan
-Integrated Pest Management Plan:
1. In the early spring, broadcast triclopyr
2. Allow the herbicide time to work its way into the soil, where it is active and
begin weakening the trees.
3. After a week, release Diorhabda beetles throughout the site, and allow them
to proliferate and weaken the tamarisk trees over time. May take up to four
years to kill trees.
4. Monitor growth, density, water and soil quality
5. Follow up with spot treatments of herbicide as needed

20. Sources
Tamarisk Removal in Grand Canyon National Park: Changing the Native–Non-native Relationship as
a Restoration Goal
Belote, R. Travis; Makarick, Lori J; Kearsley, Michael J. C; Lauver, Chris L
Ecological Restoration, 2010, Vol.28(4), pp.449-459, 2010
Vegetation Response Following Invasive Tamarisk ( Tamarix spp.) Removal and Implications for
Riparian Restoration
Harms, Rebecca S.; Hiebert, Ron D.
Restoration Ecology, 2006, Vol.14(3), pp.461-472, 2006
Ecological strategies for managing tamarisk on the C.M. Russell National Wildlife Refuge, Montana,
USA
Lesica, Peter; Miles, Scott
Biological Conservation, 2004, Vol.119(4), pp.535-543, 2004

21. Planning Riparian Restoration in the Context of Tamarix Control in Western North America
Shafroth, Patrick B.; Beauchamp, Vanessa B.; Briggs, Mark K.; Lair, Kenneth; Scott, Michael L.; Sher,
Anna A.
Restoration Ecology, 2008, Vol.16(1), pp.97-112, 2008
http://www.gcrg.org/docs/gtslib/Tamarisk-Leaf-Beetle-Life-Cycle.pdf
Bean D.W. et al. DJ, Kazmer, K. Gardner, D.C. Thompson, B. Reynolds, J.C. keller, J.F. Gaskin. Molecular Genetic
and Hybridization Studies of Diorhabda spp. Released for Biological Control of Tamarix. Invasive Plant Science and Management:
January-March, Vol. 6, No. 1, pp. 1-15.
Acharya, K. , S. Sueki ,B. Conrad , T L. Dudley , D W. Bean ,J. C. Osterberg . Life History Characteristics of
Diorhabda Carinulata Under Various Temperatures. Environmental Entemology 2013 42: 564- 571.
http://www.discovermoab.com/tamarisk.htm
http://www.tucson.ars.ag.gov/unit/publications/PDFfiles/827.pdf