Jun 16, 2023

Endemic Species of the Morro Bay Watershed

The Morro Bay watershed is home to a rich diversity of plants and wildlife, including endemic species. These are native species that are only found in a limited geographical area. The California coast is a biodiversity hotspot, and Morro Bay is no exception. This relatively small watershed of about 75 square miles is home to many species of plants and animals that are found nowhere else in the world. In this blog, we will explore some of these species in the Morro Bay watershed. 

Global biodiversity is at risk due to climate change, loss of habitat, and other human-induced factors. Endemic species are often at a higher risk of extinction due to the small area where they live and limited population size, as well as their highly specific habitat needs. Protecting endemic species is an important part of protecting global biodiversity. 

Morro Shoulderband Snail (Helminthoglypta walkeriana)

While land snails are widely distributed throughout western North America, the Morro shoulderband snail is only found from North Morro Bay to Montaña de Oro State Park. It is often mistaken for a common garden snail, although they differ slightly in appearance. They spend most of the year in aestivation, a dormant state that they enter to survive the dry season. As a result, not much is known about the lifestyle of this species. 

Two Morro shoulderband snails hiding among the iceplant on the sand spit in Morro Bay. Despite being invasive, iceplant provides crucial habitat for shoulderband snails.

In 2022, US Fish and Wildlife Service changed the status of the Morro shoulderband snail from endangered to threatened. However, this species is still at risk due to habitat loss from development. Before much was known about these snails, they were susceptible to being killed during prescribed burns and invasive plant removal projects. Snail surveys are now required before any major habitat-modifying project to try to protect this threatened species. 

This map shows documented locations of the Morro shoulderband snail from the California Natural Diversity Database (diagonal stripes), along with its preferred habitat and soil (horizontal stripes). Map courtesy of the Atlas of Sensitive Species of the Morro Bay Area.

Manzanita (Arctostaphylos spp.)

The manzanita is a distinctive chaparral plant that grows along western North America, from British Columbia into northern and central Mexico. It is easily identified by its smooth reddish-orange bark, waxy leaves, pink or white bell-shaped flowers, and fruit that resembles tiny apples. There are 105 species of manzanitas, about sixty of which are found only in California. Some species, such as the Franciscan manzanita, only have one or two known wild specimens! Of all the species of manzanita, nearly half are endangered. 

A Morro manzanita (Arctostaphylos morroensis) in Berkeley, CA. Stan Shebs, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons

There are at least four species of manzanita endemic to the Morro Bay watershed: the Morro, Oso, Pecho, and Dacite manzanitas. All four species are listed as imperiled or critically imperiled on the California Department of Fish and Wildlife’s Special Plants List. Due to their low population numbers, they are vulnerable to extinction from disease or extreme weather events. Other threats to manzanitas include urbanization, disruption of natural fire patterns, and encroachment of invasive plants such as eucalyptus. 

This map shows the distribution of the Morro manzanita (Arctostaphylos morroensis), the most widely-distributed endemic manzanita in the Morro Bay watershed. This is a popular landscaping plant, hence its presence in developed areas. Map courtesy of the Atlas of Sensitive Species of the Morro Bay Area.

Splitting Yarn Lichen (Sulcaria isidiifera)

Splitting yarn lichen near Baywood Park, CA. Photo courtesy of elibalderas on iNaturalist. https://uk.inaturalist.org/observations/51067268 

Splitting yarn lichen is a shrubby, yellow-grey lichen found in maritime chaparral and oak woodland habitats. It is endemic only to Los Osos and Baywood Park. Splitting yarn is similar in appearance to other filamentous lichens but is distinguished by a groove down the middle of its main branch (thallus) that fills with reproductive spores called propagules. All lichens are sensitive to air and water pollution, and splitting yarn lichen is at risk due to increased atmospheric pollution. 

This map shows the historical presence of splitting yarn lichen, both in documented occurrences and general distribution. Map courtesy of the Atlas of Sensitive Species of the Morro Bay Area.

How Can You Help?

Endemic species generally face a higher risk of becoming endangered or extinct compared to non-endemic species. They are particularly susceptible to climate change impacts due to their small geographic range and specific habitat needs. There are many ways to reduce your impact on climate change, including using alternate modes of transportation, using less electricity at home, and reusing or recycling rather than disposing of items. 

If you have a garden or lawn, consider using eco-friendly alternatives to pesticides and herbicides. Traditional chemical pest deterrents impact endemic native species just as much as they do invasive or “pest” species. Consider turning your yard into a native plant habitat, which will support endemic species in your area. 

Community and Citizen Science

Another way to help endemic species is by making observations on iNaturalist, a community science app and website that allows anyone to upload photos of plants and animals along with a location tag. Once a species has been verified, the data can be used by researchers, land managers, or anyone else interested in that species. Keep your eyes peeled for unusual or unique species, especially if you are in an area with known endemic species. You might be the first person to find a species outside its historic range, or one that was thought to be extinct! 












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Thank you for helping our beautiful, bountiful, biodiverse bay!