Controlling Invasions

Controlling Invasions

San Francisco Bay has been called the most invaded Estuary in the world. From Chinese mitten crabs to zebra mussels from Europe to Atlantic cordgrass from the East Coast, the Estuary has been colonized by myriad animals and plants from other parts of the country and world. Water hyacinth now clogs Delta waterways; Asian clams regularly consume all the fish food in the water column; water primrose is carpeting over native flora. Many alien animals arrived in ships’ ballast water or aquarium water dumped by unknowing home hobbyists while plants like Atlantic cordgrass were introduced intentionally by the U.S. Army Corps of Engineers in restoration projects, from which the plants then hybridized with Pacific cordgrass, creating a menacing invader. But eradicating these invaders has proved tricky. Resource managers employ both mechanical and chemical means of control, both of which can cause other, unintended consequences. Eradication and control programs also require long-term vigilance, with new species being introduced all the time, species that exploit the habitats of native species and outcompete them.

Editor’s Picks

  • Living with a Novel Landscape: Suisun Evolves
    Living with a Novel Landscape: Suisun Evolves

    Morning at Suisun Marsh is a living watercolor with a soundtrack. Miles of tule and pickleweed populate the foreground, split by canals glinting silver from the sun. In May, the hills undulate across the northern boundary in classic California gold. A red-tailed hawk’s iconic hoarse screech punctuates the insectine buzz as it takes off from […]

  • Invasive Mussels Hide in Aquarium Moss Balls
    Invasive Mussels Hide in Aquarium Moss Balls

    A few weeks ago, someone working in a big-box pet store in the Seattle area informed the U.S. Geological Survey that they had seen suspicious mollusks in ornamental aquarium plants that were being offered for sale. Federal scientists confirmed the presence of zebra mussels tucked away in a clump of Aegagropila linnaei, a green alga […]

  • Science-in-Short ~ Aquatic Weeds Podcast
    Science-in-Short ~ Aquatic Weeds Podcast

    Wall-to-Wall Sampling of the Delta’s Aquatic Weeds Via Remote Sensing, an interview with Shruti Khanna.  In this episode of the podcast, Estuary News reporter Daniel McGlynn talks to Dr. Shruti Khanna, a senior environmental scientist at the California Department of Fish and Wildlife. Their conversation focuses on Khanna’s use of remote sensing technology to study […]

  • Just Shy of Splendor in the Grass
    Just Shy of Splendor in the Grass

    Tobias Rohmer and Ben Chen’s careful work in Hayward’s Cogswell Marsh represents one small moment in the massive, nearly 20-year-old Invasive Spartina Project. Treatment of the southern section of Cogswell marsh was halted in 2011, however, due to concerns about Ridgway’s rails who’d made homes in the invader. “Complete eradication has been and still is our goal,” says Marilyn Latta…

  • Kitchen Sink Update on Every Last Invader
    Kitchen Sink Update on Every Last Invader

    On multiple fronts, with multiple forces and weapons, California’s battle against invasive aquatic organisms continues. Notoriously, San Francisco Bay is the world’s most invaded estuary. The state’s lakes, rivers, and other freshwater wetlands have their own problematic exotics. Keeping them out, and preventing their spread once established, requires coordination among agencies and levels of government.

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