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.
Spring runs of a large minnow numbering in the millions have
nourished Pomo Indians since they first made their home
alongside Northern California’s Clear Lake more than 400
generations ago. The Clear Lake hitch glinted like silver
dollars as they headed up the lake’s tributaries to spawn, a
reliable squirming crop of plenty, steeped in history and tasty
when salted and dried like jerky. In all that time, the
hitch’s domain, about 110 miles northwest of Sacramento, had
never suffered the degradation of recent years. Now, with
a growing sense of sorrow, if not anger, the Pomo Indian tribes
of Clear Lake are watching the symbol of abundance and security
they call chi dwindle into extinction…. The
hitch is a 12-inch-long minnow found only in and around the
oldest, largest and perhaps most polluted and wildfire-prone
watershed in California.
As Lake Tahoe watercraft inspections shift to winter
operations, inspectors report intercepting far fewer vessels
this year with aquatic invasive species (AIS) onboard. They
credit improvements to the program as part of the reason. The
Tahoe Regional Planning Agency (TRPA) and the Tahoe Resource
Conservation District (Tahoe RCD) announced today that out of
5,800 boats, jet skis, and trailers inspected since January, 56
were found to have AIS onboard and eight of those were carrying
quagga or zebra mussels, making this one of the lowest years on
record for intercepting the prolific invader.
Hundreds of wild pigs are destroying yards, flower beds and
more in the Lake area. However, this isn’t exactly a new thing
for Shasta County. The county has had a large population of
wild pigs for years—from Redding all the way to the Bay Area.
… Wild pigs are also nothing new for California as a
whole. In fact, even though the pigs are a nonnative species,
they have been around for years and are now as common as deer
in some places; causing chaos in local communities and forcing
residents to get creative while protecting their yards.
… There have been a lot more pigs within the Lake
community than ever before, but this can be another result of
California’s infamous drought.
In the vast labyrinth of the West
Coast’s largest freshwater tidal estuary, one native fish species
has never been so rare. Once uncountably numerous, the Delta
smelt was placed on state and federal endangered species lists in
1993, stopped appearing in most annual sampling surveys in 2016,
and is now, for all practical purposes, extinct in the wild. At
least, it was.
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.
