Presented by Julian D. Olden at the Annual Meeting of the Washington Lake Protection Association (2008)

1. Vulnerability of
Lake Ecosystems to
Species Invasions in
Washington
Julian D. Olden
Eric R. Larson
School of Aquatic and
Fishery Sciences
University of Washington
Seattle, WA USA
olden@u.washington.edu

2. Primary Threats to Washington Lakes
Habitat loss Invasive species Eutrophication
Over-exploitation Disease Climate change

3. Invasive Species in Washington
• The introduction of non-indigenous plants and animals is one of
today’s most pressing environmental challenges in Washington.
• The magnitude of this problem has been recognized in recent
decades, and state and county government agencies have
responded by designing and implementing management
strategies aimed at reducing the negative impacts of invasive
species.
• The task is daunting: landscapes to be managed are vast, there
are numerous invasive species, and funding for invasive species
management is limited.

4. Zebra mussel Nutria
Brook
trout
North
American bullfrog Eurasian
watermilfoil
Brazilian elodae New Zealand
mudsnail

5. The Challenge Ahead
• Prevention is widely recognized as the
cornerstone of most invasive species
management strategies.
• Once invasive establish self-sustaining
populations, eradication is near
impossible without high collateral damage
and excessive economic costs.

6. Washington Invasive Species
Management (2005-2007)
Total: $28,443,962
WA Invasive Species Council (2008)

7. The Challenge Ahead
• Biological invasions continue to accelerate
in Washington, and there is a need for
closer integration between invasive species
research and on-the-ground management.
• Ecologists must provide specific guidance
as to the ‘where’, ‘what’, and ‘when’ of
invasive species management efforts.
• Such information would assist managers in
the effective allocation of limited funds
and direct prevention efforts to the lakes
that are considered most vulnerable to
future invasions.

8. Smart Prevention
Guiding management efforts across vast landscapes

9. Washington Lakes
New aliens among us?
Red swamp crayfish (Procambarus clarkii)
• Red swamp crayfish is the most
widespread invasive crayfish in the
United States and the world.
• R-selected species: early maturation,
fast growth, high fecundity
Larson and Olden (in prep)

10. Red swamp crayfish
Procambarus clarkii
• The invasion of red swamp crayfish have resulted in numerous
ecological impacts manifested across entire lake food webs.
 Macrophytes KEYSTONE SPECIES
 Macroinvertebrates
 Amphibians ECOLOGICAL DOMINANTS
 Plant-eating birds
 Fish ECOSYSTEM ENGINEERS
 Turbidity, nutrients
e.g., Gutierrez-Yurriat et al. (1999), Geiger et al. (2005), Gherardi and Acquistapace (2007)

11. Western Washington Lake Survey
Red swamp crayfish
Procambarus clarkii
Signal crayfish
Pacifastacus leniusculus
Chinese mystery snail
Bellamya chinensis

12. Survey Results Red swamp crayfish

13. Biological Supply and Schools
An important vector for P. clarkii invasions?
• Red swamp crayfish was
observed in 3 school districts
(Everett, Issaquah and Federal
Way).
• Elementary schools in all
three districts participate in
the WA State LASER program,
which provides instructional
materials for teaching the
biology of life.

14. Biological Supply and Schools
An important vector for P. clarkii invasions?

15. Virile crayfish
Orconectes virilis
• First recorded presence of
Orconectes virilis in western WA

16. Golf Courses
An important vector for O. virilis invasions?
Big Lake
Lake Ballinger
Spanaway Lake

17. Current Research
• Development of management tools that predict the probability of
invasion for red swamp crayfish, virile crayfish and Chinese mystery
snail in lakes throughout western Washington.
• The identification of highly vulnerable lakes will:
– Inform education and management efforts
– Enhance early detection and rapid response
– Prioritize eradication and control efforts
• Success in invasive species management requires us to
engage the public in all stages of the invasion process,
including prevention and control.
• Examining the feasibility of whole-lake control/eradication of red
swamp crayfish/virile crayfish in lakes through extensive trapping.

18. Example: Rusty crayfish invasions
INTRODUCTION ESTABLISHMENT
• Recreational boating and bait bucket • Rusty crayfish are predicted to occupy
release are two primary transport vectors small, productive lakes that have highly
for the introduction of crayfish modified shorelines
Olden et al. (2006, unpubl.)

19. Example: Rusty crayfish invasions
IMPACT VULNERABILITY
• Invasions by rusty crayfish have been • Lake-specific vulnerability to the
associated with the local extirpation of introduction, establishment and impact of
two native crayfish species invasive rusty crayfish
Olden et al. (2006, unpubl.)

20. Example: Rusty crayfish invasions
5,164 lakes
1,350 lakes with 1+
boat landings
553 lakes that are
environmental-
suitable
1,255 lakes with 1+
at-risk species
358 highly
vulnerability
lakes

21. Current Research
• Development of management tools that predict the probability of
invasion for red swamp crayfish, virile crayfish and Chinese mystery
snail in lakes throughout western Washington.
• The identification of highly vulnerable lakes will:
– Inform education and management efforts
– Enhance early detection and rapid response
– Prioritize eradication and control efforts
• Success in invasive species management requires us to
engage the public in all stages of the invasion process,
including prevention and control.
• Examining the feasibility of whole-lake control/eradication of red
swamp crayfish/virile crayfish in lakes through extensive trapping.

22. Investigations of the Ecological Impacts of
Invasive Crayfish
Long-term Monitoring – Pine Lake

23. Acknowledgements
• Meryl Mims and Jeff Benca
• Karl Mueller (SPMC, Western
Washington University)
• Craig Busack (DFW)
• Chris Pearl (USGS)
• 2008 WALPA Scholarship to
Eric Larson