Los Angeles, USA

Hotspot & Ecoregion Status

California Floristic Province

The California Floristic Province is located along North America’s Pacific coast; it is a biodiversity hotspot of Mediterranean-type climate, with a characteristic climate of hot, dry summers and cool, wet winters. The region contains a wide variety of ecosystems. About a quarter of the original vegetation remains in close-to-pristine condition. ^[2]

Species Statistics ^[3]

	Number of species	Percentage/Number of endemics	Notable species / Additional info
Plants	~3,500	>61%	- Endangered giant sequoia ( Sequoiadendron giganteum ) and Endangered coastal redwood ( Sequoia sempervirens ), some of the tallest and most massive species on Earth
Birds	>340	<10	- most important breeding ground in the U.S. - Critically Endangered California condor ( Gymnogyps californianus )
Mammals	>150	~20	- puma ( Puma concolor )
Reptiles	~70	4
Amphibians	~50	>50%	- endemism high in salamanders
Freshwater Fishes	>70	DD	- lampreys
Invertebrates	~28,000	32%	- a-third of all known insects in the U.S. and Canada

Similarly to other Mediterranean-type ecosystems, the hotspot has more plant endemism than animal endemism; more than 61% of the 3500 native plant species found here are endemic. Four subregions within the California Floristic Province boast exceptionally high plant diversity – the Sierra Nevada, the Transverse Ranges in southern California, the Klamath-Siskiyou region, and the Coast Ranges. ^[4] Los Angeles is located just south of the Transverse Range.

Source: Ssalonen, A map of California showing topography and geomorphic provinces, Wikimedia Commons, https://en.wikipedia.org/wiki/File:California_Topography-MEDIUM.png (Accessed January 12, 2020).

While economically comparable with the most prominent countries around the globe, the Californian natural environment faces serious threats from human activities and developments. Continual population expansion leads to ever-increasing urban construction, logging, grazing, and vehicular traffic. Other major threats include large-scale agriculture, oil extraction, and strip mining. These disturbances have made California one of the four most ecologically degraded states in the US, with ecosystems such as riparian forests, native grasslands, and vernal pools nearly obliterated. ^[5]

California Coastal Sage & Chaparral

The California Coastal Sage & Chaparral ecoregion spans from northeastern Baja California of Mexico to southern California in the United States . ^[6] Bounded to the east by the Colorado-Sonora Desert, it also includes the Channel Islands (U.S) and Cedros and Guadalupe Islands (Mexico). It is one of the only five Mediterranean-climate ecoregions in the world and has extremely high levels of species diversity and endemism. Representing a myriad of habitats, coastal sage scrub, chamise chaparral, and oak woodlands are the most dominant types of landscape. Coastal sage scrub is characterized by low, aromatic, and drought-deciduous shrublands and a diverse assemblage of other shrubs, cacti, succulents, and herbaceous plants. It is a fire-adapted community; many species re-sprout from the root crown or germinate after burns. Chamise chaparral on the other hand exists generally in higher elevations but can also be found near the coast in areas with deeper soils and higher moisture content. Some indicative plants include chamizo ( Adenostoma fasciculatum ), manzanito ( Arctostaphylos spp .), and buckthorn ( Ceanothus spp .).
The ecoregion supports a large number of specialized and endemic species, for instance between 150 and 200 kinds of butterflies, the highest abundance of native bees in the United States, and several relict species. In total there are 77 species listed under the Endangered Species Act, and another 378 are under consideration. Nearly the entire ecoregion is contained within the California Endemic Bird Area. On the Mexican side, the area holds the second greatest diversity of scorpions and is also a prime zone for spiders. Many other endemic and relict plants and animals occupy the Channel Islands, sometimes only appearing on individual isles.
Much of the ecoregion has been destroyed by agriculture and ongoing urban expansion. Presently, only 15% of the region is intact, and remaining habitats are all extremely fragmented and surrounded by developments. Grazing, disruption of natural fires, and invasion of introduced species are huge threats to the local biodiversity. ^[7] Today, 11 percent of the ecoregion is under protection, and 4.78 percent is terrestrially connected. ^[8]

California Montane Chaparral & Woodlands

This ecoregion encompasses most of the Transverse Ranges, with high peaks up to 3500m (11,485 ft) tall. Such extreme topography creates a wide range of landscapes; from chaparrals, mixed-conifer forests, to alpine habitats. ^[9] The prevalence of drought-adapted scrubs distinguishes it from similar environments in the Sierras and other parts of northern California. Chamise and manzanita are representative plants dominating respectively the lower and higher chaparrals. For lower elevation woodlands, oak species are an essential component. Mixed-conifer forests occur between 1371 to 2896m (4,500 to 9,500 ft) with various combinations of incense cedar ( Calocedrus decurrens ), mountain juniper ( Juniperus scopulorum ), and many pine species. Moving towards higher grounds, the landscape transitions into subalpine forests, subalpine wet meadows, talus slope herbaceous communities, krummholz woodlands (twisted trees deformed by strong winds), and a few aspen groves. The ecoregion is also known for a variety of ecological islands – isolated, scattered habitats of specialized conditions, harboring many endemic and relict species.

Approximately 30 percent of the California Montane Chaparral and Woodlands remain relatively intact. The Ventana wilderness area supports some of the bigger unharmed habitat blocks. However, the whole ecoregion is heavily laid with roads and valley bottoms are mostly developed; these intact blocks suffer from fragmentation and isolation. Loss of riparian and aquatic ecosystems to extensive development are also prevailing issues. Fire suppression is another problem, since fuel loads accumulate and increase the probability of more devastating hot fires. Predator extirpation led to high numbers of deer, rodents, and other herbivores, resulting in intensive grazing and seed predation. These phenomena along with high-impact recreational activities have significantly damaged local flora and fauna. ^[10] At present, 24 percent of the ecoregion is protected, and 12.64 percent has terrestrial connections. ^[11]

Environmental History

The Greater Los Angeles area is nested in a coastal basin surrounded by mountains on three sides. The valleys of the region have been extensively developed f or residential, commercial and industrial use and many natural riparian corridors have been channelized . ^[12] It has great geographic variety that includes inland valleys, a coastal plain separated by low mountains, taller mountains, and a long coast along the Pacific. The area is prone to long droughts, torrential rains, intense wave surges, earthquakes, wind-fanned firestorms, and mudslides. In the past, large areas in the metropolitan area were hit by intense flooding; as such there have been significant efforts to contain waterways with infrastructure.

The city started in 1781 as a small village. Its monopoly over the LA River allowed it to annex other municipalities and local governments. Other cities joined LA, after the city built an aqueduct form the Owens River into the city, in order to gain access to water.

Over time, much of the native flora has been destroyed by ranching, farming, and urbanization, yet the area still supports many native species.

The Los Angeles urban forest cover is very diverse, with more than 600 native and non-native species and varieties represented. ^[13] More than 6 million trees provide about 11.1 percent tree cover in the city, providing valuable ecosystem services including pollution removal, carbon storage and sequestration, reducing building energy usage, and carbon emissions. Whereas preliminary studies have shown that migratory and native birds almost exclusively use native trees for nesting and feeding, only 16.1 percent of the urban forest trees in Los Angeles are native to California. ^[14]

Growth Projections + Type of Growth

The city really grew into a metropolis over the course of the 20th century. This late growth accounts in part for its sprawling, car-dependent urban form. Growth has slowed since the turn of the 21st century.

Population density varies widely across the metropolitan area, up to as high as 50,000 people per sq mile near downtown Los Angeles. The city form has many widely dispersed settlements, and most people travel between them by personal automobile (along vast freeways).

Governance

The United States government is a federal government with 50 states that have extensive-though sometimes ambiguous and often contested-powers. States establish local governments, which only have those powers that they are granted by states. The largest local government units (in most states) are counties. The next level of local government is the municipal or city government.

There are two definitions of the metropolitan area of LA. The first is defined as the Los Angeles-Long Beach-Anaheim, CA Metropolitan Statistical Area, which includes both Los Angeles and Orange counties. The population of this area was estimated at 13,310,447 in 2016. The Census Bureau has also defined the Greater Los Angeles Area (also known as the Los Angeles-Long Beach, CA Combined Statistical Area), which includes Ventura, Riverside, and San Bernardino Counties.

These metro areas can also be looked at by their municipal divisions. The City of Los Angeles is the largest principal city in the region with a population of close to 4,000,000. The second closest municipality in size is Long Beach with close to 500,000 residents. Other principal cities in Greater Los Angeles area include Anaheim, Santa Ana, Irvine, Glendale, Pomona, Torrance, Orange, Pasadena, Costa Mesa, Burbank, Carson, Santa Monica, Newport Beach, Tustin, Monterey Park, Garden, Arcadia, and Fountain Valley, and their populations range between 50,000 to 340,000. There are another 38 incorporated municipal governments that are involved in the governance of the Greater Los Angeles Area Combined Statistical area as of 2011.

City Policy/Planning

State

The State of California requires that all cities and counties in California prepare general plans. The required content of these plans and update schedules are outlined in the General Plan Guidelines, which are developed by the Governor’s Office of Planning and Research.

For example, Los Angeles County puts together a General Plan for the unincorporated parts of LA County (2,650 sq miles that are home to more than 1,000,000 people). This plan serves both as a vision document for long term investments and planning (including for example a community climate action plan, transit oriented districts, and significant ecological areas) and as a statutory document delineating zoning. The plan encompasses land use, mobility, air quality, conservation and natural resources, parks and recreation, noise, safety, public services and facilities, and economic development.

City

The General Plan framework for cities, as mandated by the State of California, functions both as a long term vision document as well as a zoning planning tool. Generally cities have a planning office that prepares, maintains, and enforces this living document.

Although the City of Los Angeles General Plan was originally passed in 1968 ^[15] , it is a dynamic planning document that has been updated in pieces over time.  The city is currently in the process of overhauling the General Plan through the OurLA2040 Initiative, which will result in a new comprehensive 20-year citywide plan.

Sustainable City pLAn is a strategic planning document that sets out goals for the city to develop more sustainably.

Biodiversity Policy/Planning

NBSAP

The United States of America is not part of the CBD and does not produce a NBSAP.

National

The USA belong to other international treaties regarding biodiversity, including the Convention on International Trade in Endangered Species of Wild Fauna and Flora and the Ramsar Convention on Wetlands. ^[16] The Endangered Species Act of 1973 guides many current biodiversity policies. ^[17]

Regional and Local

At the regional level, one example of integrated planning related to biodiversity is the Greater Los Angeles County Integrated Regional Water Management Plan: Open Space for Habitat and Recreation Plan. ^[18]

City of Los Angeles

In 2017, Councilmember Koretz put forward the City Council Biodiversity Motion, which proposed the development of “habitat-based geospatial strategies for incorporating conservation and equity of biodiversity in specific plans, development permitting, connectivity, planning, urban forestry, and the design and maintenance of parks and streets.” The first step in responding to this mandate was 2018 Biodiversity Report, developed by a coalition of agencies under the leadership of LASanitation. The Biodiversity Report assesses Los Angeles’ biodiversity using the Singapore Index of Cities’ Biodiversity. ^[19] The members of the LA Biodiversity Working Group found the priorities and metrics of the Singapore Index to be only moderately well-aligned with their own priorities, and therefore decided to develop their own index, the LA Index.

As of yet the city does not yet have an overarching Local Biodiversity Strategy, the closest thing such a strategy is the Conservation Element of the General Plan. ^[20]

The LA Planning Office has engaged with biodiversity planning primarily through wildlife corridor planning.

• Managing Agencies:

• California Department of Fish and Wildlife’s South Coast Region

• UCLA’s Institute for the Environment and Sustainability has an engaged faculty and student body that is heavily involved in academic research that supports policy development for the city (eg: report on Developing Biodiversity Indicators for Los Angeles County) ^[21]

Biodiversity/Landscape Initiatives/Projects

• The Rim of the Valley Initiative is a coordinated effort to pass the Rim of the Valley Corridor Preservation Act, which would significantly expand the boundary of Santa Monica Mountains National Recreation Area to include sites ranging from Griffith Park to the Santa Clarita Valley. As of November 2018, this Act had been referred to the House of Representatives Subcommittee on Federal Lands. ^[22]
• Urban Nature Research Center at the Natural History Museum of Los Angeles: houses an in house research team and gathers data from the public through community science projects ^[23]

• NHMLA Biodiversity Science: City and Nature (BIOScan) study ^[24]

• 2015 year-long  city initiative #BioDiversifyLA

• Partnership between NRDC, Urban Wildlands Group, Los Angeles Neighborhood Land Trust, Citizens for Los Angeles WIldlife
• Called for city official to report on strategies for biodiversity protection

• Nature Conservancy Biodiversity Analysis in Los Angeles (BAILA)

• The BAILA program is a joint initiative between the LA Natural History Museum and The Nature Conservancy to sponsor Community-based science research by which volunteer contributors build up a geo-located database of the species they encounter in the city. This data is then used by TNC scientists to develop models of how species connectivity is working on the ground in the city.
• “ It will yield a spatially explicit, wall-to-wall database and map of conservation value and potential conservation value that encompasses dense residential, industrial and commercial areas as well as natural areas and open spaces.”

• UCLA Institute of the Environment and Sustainability (IoES) Los Angeles Biodiversity Atlas ^[25]
• California Coastal Conservancy (state agency) restoration project of wetlands that will span nine miles from Port Hueneme to Point Mugu ^[26]
• Santa Monica Mountains National Recreation Area
• Mountains Recreation and Conservation Authority
• Santa Monica Mountains Conservancy
• Friends of the Los Angeles River || LA River Ecosystem Restoration Project ^[27]
• The Trust for Public Land Green Alleys Los Angeles Program ^[28]
• LA River Masterplan (commissioned by LA County)

• This plan is currently under development by a team that includes OLIN Studio, Geosyntec, and Gehry Partners. It was commissioned by LA Country, and is one of many plans for the LA River drawn up over time at various scales.

Public Awareness

Southern California was historically called “a paradisiacal garden” that was “awaiting only the shaping hands of human action and labor” ^[29] . The now common perception of this region as the lush land of oranges and palms is an entirely constructed image that relies heavily on massive imports of water and extensive irrigation systems. ^[30]

During the last decade, mountain lions have become a symbol for Angelenos of both the incredible resilience and perseverance of biodiversity in a sea of urbanization as well as the continually mounting and compounding threats this biodiversity faces. A handful of pumas have become local celebrities as they have navigated their way across expansive highways to pockets of habitat across the city. P-22, the lone mountain lion resident of Griffith Park, crossed two major highways in an effort to escape from more aggressive and territorial males in the Santa Monicas. His continued residence in Griffith park (even after he killed an endangered koala in Los Angeles zoo) has been largely seen as a victory for biodiversity protection in the city as residents have not just acclimated to the dangerous cat living in their backyard, but have welcomed him and championed his protection. Yet P-22 is living completely isolated from other mountain lions, meaning that the only way he could produce offspring would that he or a female mountain lion would have to cross more deadly highways. The isolation of mountain lions in pockets in the Greater Los Angeles region has led to detrimental inbreeding, a threat to the integrity of the population’s genetic health. In order to ensure survival of mountain lions, more individuals will have to be brought in either via direct transport or by developing extensive, safe and inviting wildlife corridors . ^[31]

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