Living with a Novel Landscape: Suisun Evolves

Invasive Species



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 a powerline. At 7:40 AM, it’s already 72 degrees and there’s no trace of a breeze. I’ve come to visit the Marsh from downtown Oakland seeking to learn from biologists, hunters, and land managers what’s at stake in the myriad battles with rising seas, worsening drought, and, especially, encroaching invasive species and what makes it such a singular, attractive landscape.  Indeed, the pastoral foreground is...
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25
Oct

Invasive Species Breakdown

The invasion of the Delta continues, with new plants and animals threatening to upend ecosystems alongside established non-native species like largemouth bass and spartina. Preventative measures, early detection, and rapid response to novel threats are all key in protecting the Delta from further disruption. But the concepts of community involvement and reconciliation ecology also encourage land managers to consider non-natives with nuance. This means accounting for the cultural and ecological values of invasive species and, in some cases, learning to accept their presence on the landscape while still prioritizing natives. These were among the takeaways of the Estuary Summit’s lunchtime breakout discussion of invasive species in the Delta (one of seven breakout sessions, on topics ranging from water quality to...
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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 marketed as moss balls or marimo balls, and issued a warning through the Nonindigenous Aquatic Species Alert System on March 2. The national Aquatic Nuisance Species Task Force, co-chaired by the U.S. Fish and Wildlife Service and the National Oceanic and Atmospheric Administration, swung into action, bringing in regional networks and state wildlife agencies. On March 3, Martha Volkoff at the California Department of Fish...
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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 the Sacramento-San Joaquin Delta. Specifically, Khanna analyzes and processes remote sensing data, or high- resolution images collected by sensors mounted on aircraft, to study invasive plant species growing in Delta waterways. Researchers also use remote sensing to study the Delta’s water quality, fish populations, and overall change. While remote sensing will never replace on-the-ground research, the massive data set produced by collecting large-scale images over...
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Makeover for Delta Weed Patch & Salt Trap?

What began as a project to convert a submerged Delta island into habitat for endangered native fish has morphed into a multi-benefit package with additional payoffs for water quality and recreation. The collaborative design process for the Franks Tract Futures project brought initially skeptical local stakeholders on board and is being hailed as a model for future initiatives. Yet major uncertainties remain as interested parties explore the challenges of implementing a complex redesign of a big chunk of the Delta. The proposed project would take a big shallow lake full of weeds, deepen some parts, fill in others with new lands and fish habitats, add beaches and recreational amenities, and stanch the spread of salt water from the ocean toward...
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13
Sep

Yet another non-native aquatic species may have made itself at home in the Delta.

As described by US Fish and Wildlife Service fish biologist Brian Mahardja and his co-authors in San Francisco Estuary & Watershed Science, the newcomer is an inch-long, minnow-like fish called the bluefin killifish (Lucania goodei), indigenous to Florida and adjacent southeastern states. It was first detected in the Delta Cross Channel during a beach seine survey in October 2017, and subsequently found in Beaver and Hog sloughs and at Decker, Sherman, and Brannan islands. With surveys curtailed by the coronavirus pandemic, current data is sparse, although 13 were caught before March and one was caught in June. Bluefin killifish are popular in the freshwater aquarium trade, and the authors suspect the founders of the Delta population were released by a...
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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...
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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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02
May

Nutria — giant South American rodents—are breeding in the San Joaquin Valley and are on the brink of invading the Delta, where they could wreak havoc, as they have done in Louisiana, Chesapeake Bay and the Pacific Northwest.

According to the California Department of Fish and Wildlife, nutria have extremely destructive feeding habits that often lead to severe soil erosion, in some cases converting marsh to open water. Nutria also burrow into banks and levees, creating complex dens that extend as much as 6 meters deep and 50 meters into the bank, often causing severe streambank erosion, increased sedimentation, levee failures, and roadbed collapses. The rodents, which can weigh more than 20 pounds and are often mistaken for beavers or muskrats, were introduced to California for the fur trade in the early 20th century, but were eradicated by the 1970s. In 2017 a reproducing population was discovered in the San Joaquin Valley and nutria have now been confirmed...
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13
Dec

Table Set for Snails

Several months ago, Mike Moran of the Delta’s Big Break Regional Park got a call about a cluster of unusual looking eggs. “We thought we might be looking at this channeled apple snail thing,” he says.
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13
Dec

Searching for a Few Good Weevils

“They’re pretty charismatic,” says Julie Hopper of the tiny herbivorous weevil N. bruchi. Native to Argentina, these weevils were first brought to North America to combat the spread of the invasive weed water hyacinth.
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