Biodiversity of Napa County

We live in a hotspot known as the  California Floristic Province , located along North America's Pacific coast.

This biodiversity hotspot is a zone of Mediterranean-type climate, characterized by hot, dry summers and mild, wet winters.

Mediterranean climates are rare but significant - covering only 2% of Earth's land area, but home to 20% of all the plant species in the world. (International Union for Conservation of Nature.)

 Crain and White 2013 

Napa County represents less than .5% of California it contains 1/3 of the state’s native plant species and a uniquely high level of native fish diversity. (Napa County General Plan 2009)

Likely, 60 special-status wildlife species: 39 birds, 11 mammals; 5 invertebrates, 3 amphibians, and 2 reptiles.

81 special-status plant species, 7 of which are endangered.

24 rare animal species tracked by the California Natural Diversity Database.

 Napa County Biological Resources General Plan DEIR (click for link) 

Napa County contains the eastern-most populations of coastal redwood forests in California, including trees which began growing around 1200 AD.

Napa County is extremely unique for its valley oak woodland forest-type, which harbor some of the  highest plant and animal diversity in California . Oaks remove more carbon dioxide from the atmosphere per year than many other common landscaping trees and live for over 400 years.

Marshes and wetlands of southern Napa County and the San Francisco Bay Area have been designated as wetlands of  "International Importance"  for their many ecosystem services.

Hundreds of species of birds including shorebirds, ducks, and birds of prey rely on habitats of Napa County for shelter, feeding, nesting, and resting. Migratory species such as  cliff swallows  using the Pacific Flyway connect us to ecosystems in Alaska, Canada, and Central and South America.

The Napa River has historically and currently supported the largest steelhead trout run in the Bay Area, and has one of the highest diversities of native fish species.

Out of all 9 Bay Area counties studied, the Napa River and Suisun Creek watersheds have been identified as  "anchor watersheds,"  or ecosystems with the highest possibility of restoration to their historical state.

 Historical status of coho salmon in streams of the urbanized San Francisco estuary, California (Leidy 2005) 

 Special status species  are considered significantly rare and require special consideration and protection.

Special status species can be labeled as rare, threatened or endangered.

A  threatened species  is declining in population and could become an endangered or extinct species.

Pictured here is a Ridgway's rail, a native and endangered species found in the bay area wetlands. This species is almost entirely endemic to the San Francisco Bay Estuary, where the only known breeding population exists.  (US Fish and Wildlife Service, 2017) 

The salt marsh harvest mouse is another endangered and endemic species to our local salt marshlands.

They are one of the only mammals that can drink salt water to survive, and one of the only mice species that can swim.

The St. Helena Fawn Lily is a rare plant found only in Napa, Lake and Sonoma counties. Blooming from March-May, this plant is fairly endangered and is threatened by horticulture collection, road construction and geothermal development ( California Native Plant Society )

The Calistoga Popcornflower is a rare and threatened species with only 2 known populations growing on privately owned land near Calistoga.

 _{Photo credit: Robert E. Preston, Ph.D.  2014}