Support healthy, connected ecosystems.

The river is an important ecosystem that supports a variety of plant and animal life throughout the highly urbanized landscape of LA County.

KCET Departures, South L.A. Willow Street, 2010. Source License: CC BY-NC-ND 2.0.

The LA River watershed sits within one of the world’s most diverse Mediterranean biodiversity hotspots and along the Pacific Flyway.

Due to urbanization, the region has the largest number of endangered and threatened species and species of special concern in the contiguous 48 states.¹ The river ecosystem has been altered from its historic state, first through agriculture and irrigation and later through channelization. In community meetings and surveys, 52% of participants said the issue most important was protecting vulnerable plants and animals. Planning and development efforts along the river must create habitat areas large enough to support native functioning ecosystems.

Actions

Steps that should be taken to achieve the goal

Use the river corridor as a living laboratory where ongoing innovation is encouraged.

Use environmentally responsible practices for operations and maintenance of the river channel and adjacent lands.

Increase habitat and ecosystem function along the river corridor.

Increase plant species biodiversity, and focus on the use of local California native plants in and around the river corridor.

Create a connective network of habitat patches and corridors to facilitate the movement of wildlife and support a diverse resilient ecological community.

Encourage cities along the river to adopt sustainability strategies.

LA River Ecosystems Need

Needs: Ecosystems

In an urban environment like LA, sustaining healthy ecosystems requires protecting areas with high biodiversity; enhancing, expanding, and adding habitat in strategic locations; and creating linkages between habitat areas.

Need for ecosystems was evaluated by combining the need to protect and manage existing habitat areas, large areas with remaining native vegetation, with the need to expand these habitat areas through habitat buffers. Linkages, potential connections between habitat areas, such as LA River tributaries and confluences were also used to evaluate the need for ecosystem improvements. Like ecosystems themselves, data on existing habitats is always evolving and other areas may also be of high importance. Additional data should be included as it becomes available and site-by-site evaluation is needed to confirm existing ecological conditions. As the map shows, all areas have need in LA County for healthy, functioning ecosystems.

Habitat Areas

CALVEG Regional Dominance types from the USDA Forest Service were used to classify existing areas as predominantly urban or barren, native or natural, or invasive vegetation. Areas with native or natural landcover were considered habitat areas and were designated as very high need due to the importance of managing these few remaining areas of native plant habitat. Areas that were agricultural or barren were categorized as general need and areas that were predominantly urban were categorized as having no need. Areas not categorized as habitat may still have an overall very high need if they are near a strategic location such as an existing habitat area buffer, linkage or confluence, or are unprotected. More locally, communities known to have less access to nature and a high potential for ecosystem improvements should be prioritized.

Habitat Areas Buffer

Areas closest to existing protected habitat areas (within 1,000 feet) that could help further buffer core protected habitat areas were categorized as having very high need. Areas further than 1,000 feet were categorized as general need.

Linkages and Confluences

Missing linkages are areas without connectivity, but based on their location, are critical to improving ecosystem connectivity. These linkages were identified by the 2008 South Coast Missing Linkages Project. Tributaries and confluences can also provide opportunities for species to move throughout the LA Basin. Areas closest to a missing linkage, tributary, or confluence were categorized as very high need. Areas up to 5,000 feet were categorized as general need, and areas further than 5,000 feet away were categorized as no need.

Unprotected Areas

Unprotected areas are vulnerable to development and are less likely to sustain habitat areas over time. Ecosystems that are in areas that are unprotected have very high need. Protected areas, which were categorized as general need, were identified based on the California Protected Areas Database.

Sites with Very High Need for Ecosystems

Estuary

W 28th St to 405 Freeway

Central Plain

Parque Dos Rios

Design Components that Address Ecosystems

Channel Modifications

Crossings & Platforms

Diversions

Floodplain Reclamation

Off-Channel Land Assets

Trails and Access Gateways

Case Studies

Atlantic Park De Las Llamas, Santander, Spain

Atlantic Park de Las Llamas is located in the center of Santander, Spain. This park space transformed a former trash dump site into an ecologically rich urban park. The park utilizes a three tier design strategy to create different habitat types throughout the project. These tiered ecosystems remove pollutants from the runoff and provide infiltration opportunities in the heart of the city.

Lessons Learned

Success came from the project’s ability to blend the public and urban uses with the necessary ecosystem functions
Highly designed public space has proven to operate successfully in terms of ecosystem functions
Providing access from all points of the surrounding neighborhoods and communities maximized its urban potential
The park successfully utilized geometric forms for waterway/waterfront design of public space