One of the San
Dieguito River Park's primary goals is to be a good steward of the land. We work hard to improve native habitat and water quality in the San Dieguito River Valley. Click below to learn more about some of the different ways that the River Park is involved in Resource Management.
Invasive Plant Species -controlling invasive plant species is a major endeavor in the River Park. From 2003-2008 we focused on controlling the spread of Perennial Pepperweed (Lepidium Latifolium) using a grant from California State Parks. With new funding obtained by our sister organization, the San Dieguito River Valley Conservancy, from the Natural Resources Conservation Service, The San Diego Foundation and the US Fish & Wildlife Service's Partners for Wildlife Program we are extending our efforts to remove Giant Reed (Arundo donax), Tamarix and continuing control of Perennial Pepperweed. These species are primarily located in the Lake Hodges and San Pasqual Valley areas. We will also be removing eucalyptus trees in the Del Dios Gorge area, and will replace them with native trees such as sycamore. To read about why it is important to control invasive plant species, please click here.
Bullfrog Control -not all invasive species are plants. The bullfrog (Rana catesbeiana) is a devastating predator. Native to North America east of the Rocky Mountains, bullfrogs are now found
throughout the world. In many areas outside their native range, the frogs are
outcompeting—and eating—just about everything in their path. According to biologists, bullfrogs began their leap around the world in 1898,
when they were imported to California to satiate a consumer appetite for frog
In their native habitat, predators such as large water snakes, alligators, and snapping turtles keep adult bullfrogs in check, while fish slurp tadpoles. But in western North America and other regions of the world, effective bullfrog predators are absent.
In the absence of predators, the bullfrogs' prolific nature allows them to flourish. "A bullfrog may lay, in a single clutch, 20,000 eggs. Studies of bullfrog intestines reveal the amphibians eat just about anything
they can fit into their mouths: birds, rats, snakes, lizards, turtles, fish,
and other frogs. Their lack of predators, prolific nature, and incentive to relocate make
bullfrogs a difficult invasive species to eradicate. No single method has proved
effective in eliminating them.
The San Dieguito River Park has initiated a program to reduce the bullfrog population on Park-owned property in the Santa Ysabel Gorge area with a grant from SANDAG's Transnet EMP program. The next area that the River Park will target is in the Del Dios Gorge, downstream of the Lake Hodges Dam.
Coastal Sage Scrub and Cactus Scrub Habitat Restoration - Restoring native habitat has always been a high priority in the River Park. However, after the Witch Fire of October 2007, which burned approximately 62% of the natural areas of the Park, we have pursued restoration of these habitats with renewed vigor. The reason for this is our concern that the loss of these habitat communities could lead to the local extirpation of two threatened bird species - the California gnatcatcher and the cactus wren. Click here for photos of the cactus wren and more information on what the River Park and its partners are doing to restore habitat for this threatened bird.
Water Quality - Improving water quality in the River Park involves reducing impacts from urban runoff pollutants such as chemicals from pesticides, nutrients from fertilizer, sediment and oils. The biggest project that the River Park has undertaken to improve water quality is in the coastal area where we constructed a series of four inter-connected treatment ponds that will clean urban runoff through the use of natural vegetated swales before that water enters the newly created adjacent tidal wetland restoration project. To read more about this project, click here.
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