Attack of the Aquatic Habitat Snatchers By: Cynthia Ribitzki For: SWES 474
Aquatic Habitat Snatchers Alter the surrounding ecosystem by • Changing surround benthic and pelagic animal communities • Displacing native plants • Shifting chemical processes (i.e. like the nutrient cycle) • Changing sediment characteristics and deposition
Tamarix (Salt Cedar) • Eliminates surface water, lowering the local water table • Increases salinity of soil • Tolerates up to 36,000ppm • Increases frequency, intensity, and effect of fires and floods
Melaleuca Quinquenervia (Melaleuca) • Turning “River of Grass” into “River of Trees” • In 50 years, it has taken over hundreds of thousands of acres of Everglades
Typha Angustifolia • Displaces native plants • Impedes water flow • Increases sedimentation • Changes sediment chemistry • Green Areas indicate Typha regions
Eichhornia Crassipes (Water Hyacinth) • an acre of water hyacinth can weigh more than 200 tons; infestations can be many, many acres in size; mats may double their size in as little as 6-18 days • I’ll enlighten you on the problems this can cause.
Myriophyllum Spicatum (Eurasian water-milfoil) • Explosive growth during early colonization • Forms dense mats • Reduces food quality • Reduces oxygen levels in water
Hydrilla verticillata (Hydrilla) • One square meter of hydrilla can produce 5,000 tubers. • Tubers can withstand ice cover, drying, herbicides, and ingestion and regurgitation by waterfowl. • Once hydrilla becomes established, it is readily spread by waterfowl and boating activities. • Growth creates dense mats • Promotes anoxia • Limits movement of predatory species
Spartina Alterniflora (Smooth Cord Grass) • Ecosystem Engineers • The San Francisco INVASION • The European INVASION
S. Alterniflora (cont.) Ecosystem Engineering • “The indirect or direct control of resource availability mediated by an organism’s ability to cause physical state changes in abiotic or biotic materials… in essence the creation, destruction, or modification of habitats.” -(Crooks 2002)
S. Alterniflora vs. S. Foliosa • S. foliosa is the native species of cordgrass in the San Francisco Bay area. • S. alterniflora was introduced in the mid-1970s. • 60 cm taller • Produces almost 10-fold the above ground biomass • Higher potential for sexual reproduction • Spreads laterally 1.5 times faster
The S. Alterniflora Invasion Continues • Impedes water flow • Causes threat of channel blockage in narrow up-river channels • Covers open mud • Changes patterns of species diversity
The European Invasion: S. anglica is born! S. Alterniflora is the maternal genome donor of S. anglica. This could explain why S. anglica is covering most of the coast along the British Isles.
The Threat of Invasion • S. alterniflora has the ability to “homogenize biotas across biogeographic realms and alter evolutionary pathways”. • A few offspring of S. alterniflora can threaten the abundance of plant species in Europe and the extinction of S. foliosa in the San Francisco bay area, if the hybrids have superior male fitness.
Conclusion? Aquatic Habitat Snatchers are running a muck! AGH! Just Kidding!
Solutions Suggested Control Methods for S. alterniflora and its hybrids Selectively removing them from native marshes where invasion has not run a muck Herbicide sprays Monitor un-invaded marshes to prevent future invasions • Use only S. foliosa for restoration projects