Conservation

Invasive Species

Parkway Invader Alert!

Our Parkway has many invasive weeds that are threatening the native San Joaquin River ecosystem and its recreational uses.

What is an invasive weed?

A weed is a plant that is unwanted where it is growing. A plant considered a weed in one area might not be considered a weed in another area. Think of a dandelion in a lawn. Most people work aggressively to keep dandelions out of their lawns. However, your neighbor down the street may grow dandelions in their garden for food or medicinal purposes and would not consider the dandelion to be a weed.

A weed becomes an invasive weed when it is not only unwanted but also spreads aggressively in an area and displaces the other plants that were growing there. The invasive weed can become dominant and completely displace a native habitat. When native habitats are displaced, it sends a ripple effect through the local ecosystem, affecting insect pollinators, bird populations, and wildlife. In a riverine system, overgrowth of weeds in a water channel decreases the amount of water available, increases risk of flooding and can increase fire hazards.

When weeds become a public nuisance, we all need to pull together to help eradicate them and/or control their spread.

What do invasive weeds do to the San Joaquin River ecosystem?

In general, invasive weeds:

Out-compete native plants for nutrients, water, light and space
Block access to the river for both animals and people
Decrease water quality
Decrease the amount of food available for fish
Increase fire and flood danger
Interfere with irrigation canals and pumps
Increase erosion problems
Fail to provide food, shelter, and breeding sites for native animals and pollinating insects
Decrease the amount of water in the river channel

Follow the links below to learn more about the invasive plants in the Parkway, what’s being done about them and how you can help.

Arundo donax (Giant reed, giant cane)
Sesbania punicea (Scarlet wisteria, Rattlebox, Red sesbania)
Tamarix spp. (Tamarisk, Salt Cedar)

If you are interested in receiving periodic email updates on our Invasive Weed Management Program, including current projects and volunteer opportunities, email Watershed Program Director Sharon Weaver at sweaver@riverparkway.org, or call (559) 248-8480 extension 105.

For further information about invasive weeds, follow the links below: