Invasive species, also known as exotics, are plants, animals,
insects, and aquatic species introduced into non-native habitats.
Without natural predators or threats, these introduced species
then multiply.
Often,invasive species travel to non-native areas by ship,
either in ballast water released into harbors or attached to the
sides of boats. From there, introduced species can then spread
and significantly alter ecosystems and the natural food chain as
they go. Another example of non-native species introduction
is the dumping of aquarium fish into waterways.
Invasive species also put water conveyance systems at risk. Water
pumps and other infrastructure can potentially shut down due to
large numbers of invasive species.
Government officials warding off deadly diseases often praise
the lowly mosquitofish as a public health messiah. But some
environmentalists have dubbed it the “plague minnow” and the
“fish destroyer.” Today, nearly a century after the
finger-sized fish was first introduced to California in a
Sacramento lily pond, it’s arguably the most ubiquitous
freshwater fish in the world. But the mosquitofish also ranks
among the world’s worst invasive species. Balancing the
pest-control prowess and ecological destruction of the fish,
nearly every mosquito and vector control district in
California, including in Marin, now deploys the creature with
varying strategies.
Government officials warding off deadly diseases often praise
the lowly mosquitofish as a public health messiah. But some
environmentalists have dubbed it the “plague minnow” and the
“fish destroyer.” Today, nearly a century after the
finger-sized fish was first introduced to California in a
Sacramento lily pond, it’s arguably the most ubiquitous
freshwater fish in the world. But the mosquitofish also ranks
among the world’s worst invasive species. Balancing the
pest-control prowess and ecological destruction of the fish,
nearly every mosquito and vector control district in California
now deploys the creature with varying strategies.
As invasive plants encroach on the pristine waters of Lake
Tahoe, officials are weighing whether to use aquatic herbicides
for the first time to contain their growth and prevent them
from clouding the waters. Plants like curlyleaf pondweed and
eurasian watermilfoil have long thrived in the Tahoe Keys, a
boating community located on a lagoon off the southern end of
the lake. … Along with some scientists and lake
protection groups, [local property owners are] lobbying
the Tahoe Regional Planning Agency Governing Board and the
Lahontan Regional Water Quality Control Board to permit
herbicide use in the Keys.
It’s turning into a battle of survival between non-native trees
and the native ones at the El Capitan Reservoir. The San Diego
River Park Foundation is working in partnership with the U.S
Forest Service, the Research Conservation District of Greater
San Diego, the Backcountry Land Trust and the City of San Diego
to remove invasive trees along our local watershed.
A pair of agencies are teaming up to begin the largest invasive
plant removal project at Lake Tahoe, officials announced
Wednesday. The USDA Forest Service Lake Tahoe Basin Management
Unit, in partnership with the Tahoe Regional Planning Agency,
are planning to remove 17 acres of invasive plants in the
Taylor and Tallac creeks and marshes as part of a comprehensive
restoration of one of the last natural wetlands in the Lake
Tahoe Basin. Left unchecked, aquatic invasive plants can have
devastating effects on Tahoe’s ecosystem and recreational
resources.
The battle to eliminate a destructive swamp rat in Central
California waterways is showing signs of improvement. However,
a state biologist says declaring victory is still years
away. Since 2017 the State Department of Fish and Wildlife
has tracked the nutria from Stockton to Mendota. It’s a very
destructive rodent that can tunnel through rivers, ponds, and
wetlands creating all kinds of problems. … Twenty nutria
trapped and euthanized in the final months of 2017. A year
later it climbed to 348, 489 in 2019, 1242 in 2020, and this
year the number finally took a downward trend at 674.
This tour guided participants on a virtual journey deep into California’s most crucial water and ecological resource – the Sacramento-San Joaquin Delta. The 720,000-acre network of islands and canals support the state’s two major water systems – the State Water Project and the Central Valley Project. The Delta and the connecting San Francisco Bay form the largest freshwater tidal estuary of its kind on the West coast.
The growing leadership of women in water. The Colorado River’s persistent drought and efforts to sign off on a plan to avert worse shortfalls of water from the river. And in California’s Central Valley, promising solutions to vexing water resource challenges.
These were among the topics that Western Water news explored in 2018.
We’re already planning a full slate of stories for 2019. You can sign up here to be alerted when new stories are published. In the meantime, take a look at what we dove into in 2018:
Sixty percent of California’s developed water supply
originates high in the Sierra Nevada mountains. Our water
supply is largely dependent on the health of our Sierra forests,
which are suffering from ecosystem degradation, drought,
wildfires and widespread tree mortality.
We headed into the foothills and the mountains to examine
water issues that happen upstream but have dramatic impacts
downstream and throughout the state.
GEI (Tour Starting Point)
2868 Prospect Park Dr.
Rancho Cordova, CA 95670.
For more than 100 years, invasive
species have made the Sacramento-San Joaquin Delta their home,
disrupting the ecosystem and costing millions of dollars annually
in remediation.
The latest invader is the nutria, a large rodent native to South
America that causes concern because of its propensity to devour
every bit of vegetation in sight and destabilize levees by
burrowing into them. Wildlife officials are trapping the animal
and trying to learn the extent of its infestation.
Estuaries are places where fresh and
salt water mix, usually at the point where a river enters the
ocean. They are the meeting point between riverine environments
and the sea, with a combination of tides, waves, salinity, fresh
water flow and sediment. The constant churning means there are
elevated levels of nutrients, making estuaries highly productive
natural habitats.
A troublesome invasive species is
the quagga mussel, a tiny freshwater mollusk that attaches itself
to water utility infrastructure and reproduces at a rapid rate,
causing damage to pipes and pumps.
First found in the Great Lakes in 1988 (dumped with ballast water
from overseas ships), the quagga mussel along with the zebra
mussel are native to the rivers and lakes of eastern Europe and
western Asia, including the Black, Caspian and Azov Seas and the
Dneiper River drainage of Ukraine and Ponto-Caspian
Sea.
This 24×36 inch poster, suitable for framing, explains how
non-native invasive animals can alter the natural ecosystem,
leading to the demise of native animals. “Unwelcome Visitors”
features photos and information on four such species – including
the zerbra mussel – and explains the environmental and economic
threats posed by these species.
This 24×36 inch poster, suitable for framing, explains how
non-native invasive plants can alter the natural ecosystem,
leading to the demise of native plants and animals. “Space
Invaders” features photos and information on six non-native
plants that have caused widespread problems in the Bay-Delta
Estuary and elsewhere.
The 24-page Layperson’s Guide to the Delta explores the competing
uses and demands on California’s Sacramento-San Joaquin Delta.
Included in the guide are sections on the history of the Delta,
its role in the state’s water system, and its many complex issues
with sections on water quality, levees, salinity and agricultural
drainage, fish and wildlife, and water distribution.
