Management Plan
Invasive Species and Biodiversity
Controlling invasive species
The term invasive is generally used to describe plants and animals that have the capacity for explosive population growth, becoming widespread and eventually dominating ecosystems. The emphasis on native plants and animals in ecological restoration is simple: indigenous species are much more likely than exotic species to have evolved mutual ecological relationships with local predators and competi-tors. Indigenous species thus provide a balance that naturally allows for biological diversity and abundance.
Weedy Plants and animals
Controlling weedy plants and animals is a necessary part of land management in the Laguna, but the fundamental goal is to increase the self-sustaining ability of the Laguna’s ecosystems to resist invasion by weedy species, and to prevent the introduction of new weeds. After prevention, the most effective management approach to invasive species are programs that employ a policy of “early detection and rapid response.” Weed mapping and monitoring programs are essential for early detection and rapid response to initial infestations, and are a central component of adaptive management frameworks for large-scale invasive species control.
Restoration Practices
The restoration practices that are most likely to suppress invasive species include: nutrient reductions, restoration of hydrologic conditions, and restoration of healthy riparian corridors. Reducing soil disturbances can also help to forestall the colonization of new territories. Biological control—introducing specialized herbivores, predators or pathogens—can be a very effective management solution, bringing popu-lations of the invader to low, sustainable levels. Controlling weeds with grazing animals is another form of biological control, and has many advantages.
There is always a tension between the need for management action and the ability for science to provide rapid answers. Although it is sometimes necessary to move forward with incomplete information, whenever possible, invasive species control projects should include a research component to help plan and evaluate the success of management actions.
Preserving Biological Diversity
Historical accounts of the Laguna describe a very different landscape, highly productive, and filled with wildlife—some of which disappeared in the 19th century: Tule elk, pronghorn, wolves, grizzlies, beavers and California condors. Other species have been extirpated within recent memory: yellow-billed cuckoos, porcupines and badgers. Some species are on the verge of disappearing from the watershed and sightings are infrequent: California mountain lion, bobcat and river otters. Several plants and animals are endemic to this area of Northern California—naturally occurring nowhere else on Earth—and the joint forces of environmental change and development have put their populations at risk of extinction.
Preserving the diversity of the Laguna’s plants and wildlife is a core value expressed by biologists and codified through treaties and laws such as the Migratory Bird Treaty, Endangered Species Act, and Clean Water Act. Fifteen plants and animals still found within the Laguna are federally listed as threatened or endangered, and thirty-eight are listed by the State of California as threatened, endangered, or species of special concern. In addition, the California Native Plant Society has designated forty-three plants as species of local concern. (A tabulation of all these species appears in an appendix.) But in compiling the list of threatened and endangered species, the Biodiversity Advisory Committee was concerned with common species as well—species should not have to be at the edge of extinction to be the target of conservation efforts.
Anadromous fish
Anadromous fish, including steelhead, coho and chinook salmon were historically present in large numbers along several of the Laguna’s major tributaries; these species were the foundation of an economically important fishing industry in the Russian River basin, but their populations have crashed in response to a variety of factors—including habitat degradation of spawning areas, and the occurrence of overly warm, oxygen deficient, silt-laden waters in the Laguna’s main channel. Restoration activities should be designed towards the recovery of all three species, with greatest recovery, in numbers, foreseen for steelhead. The most important and least costly activity for salmonid recovery is enhancement of riparian canopy. Special emphasis should be given to Mark West Creek, Santa Rosa Creek, and Copeland Creek, with particular attention given to enhancing safe passage through the Laguna and the low velocity channels that cross the Santa Rosa Plain.
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