mosquitoes, wetlands and aquatic plants

Mosquitoes in Constructed Wetlands

Dr Cameron Webb

 Department of Medical Entomology

Pathology West – ICPMR Westmead, Westmead Hospital

Marie Bashir Institute of Infectious Diseases and Biosecurity, University of Sydney

Email: Cameron.webb@health.nsw.gov.au

Twitter: @mozziebites

• Most common in Australia (~5,000 cases/pa)• Symptoms: 

Not fatal but rash, fever, joint pain, polyarthritis

• Complex ecology, in different regions: Seasonal & geographic variation Different vectors

• Marsupial hosts? Bird hosts? Human hosts?

Ross River & Barmah ForestRoss River & Barmah Forest

Water Sensitive Urban Design Integration of water management into

urban planning and design Urban developments contain a suite

of water conservation strategies Constructed wetlands Bioretention swales Raingradens Rainwater tanks

Mosquito risk variable Design, construction, installation and

maintenance issues can increase the mosquito risk

Constructed WetlandsConstructed Wetlands Stormwater retention & treatment Wildlife conservation Change local mosquito diversity Change in local environmental

drivers of mosquito populations Change in reservoir hosts Wetland design & maintenance

Water quality, depth & flow rates Edge structure and slope Vegetation zones Predators

Well funded management plan

Wetlands support diverse habitats

Vegetation and mosquito risk?

Stem density: multiple stems increase refuge Growth density: more plants per area Invasiveness: create monoculture Plant litter: increase refuge & organic content Deep water tolerant: potentially greater coverage Floating plants: density & root mass provides refuge Terrestrial plants: grow into water & provide refuge? What plants are required to meet wetland objectives

Plant group Plant nameMosquito Risk

High Med Low

Emergent Alisma spp. (e.g. Water Plantain) +

Sagittaria spp. (e.g. Arrowhead) +

Cyperus spp. (e.g. Giant Sedge) +

Typha spp. (e.g. Cumbungi) +

Phragmites spp. (e.g. Common Reed) +

Bolboschoenus spp. (e.g. Clubrush) + +

Eleocharis spp (e.g. Common Spikerush) +

Persicaria spp. (e.g. Slender Knotweed) +

Floating Azolla spp. (e.g. Water Fern) +

Eichhornia spp. (e.g. Water Hyacinth) +

Lemna spp. (e.g. Duckweed) +

Potamogeton spp. (e.g. Pondweed) +

Salvinia spp. (e.g. Salvinia) +

Ranunculus spp. (e.g. Buttercups) +

Based on Knight et al. (2003) Ecol. Engineering 21:211-232 & Sainty and Jacobs (2003) Waterplants in Australia

Estimated mosquito risk associated with aquatic vegetation

Provides assistance to local governments on assessing mosquito risk associated with wetlands

Provides background on mosquito and mosquito-borne disease risk

A framework for decision making

Highlight wetland projects that may require more detailed assessments and the engagement of consultants to develop a site-specific plan

Guidelines for constructed wetlands

Wetland RehabilitationWetland Rehabilitation Accompany development More mosquitoes?

Restore tidal flooding (coastal) Environmental flows (inland)

Long-term & short-term issues Change in local environmental

drivers of mosquito populations Change in reservoir hosts Mosquito management? Are these “natural” habitats?

Regional Approaches to Mosquito RiskRegional Approaches to Mosquito Risk

Follow me on Twitter @mozziebites

Learn more about my research:

http://cameronwebb.wordpress.com

Thank you