By Melissa Baffa

Representatives from the Ventura Land Trust were invited to participate in a tour of the conservation work being done by the Catalina Island Conservancy (CIC) on Catalina Island, 26 miles across the sea (as the song goes) from the port of Long Beach.

Representatives from conservation groups, elected officials, and other CBOs attended. After lunch and an overview, we split into groups and went to the island interior to see the project elements firsthand. The biggest challenge faced by the CIC is the island’s population of voracious, invasive mule deer, introduced for the purpose of hunting. These deer, with no natural predators, are adversely affecting native species on the island and forcing type conversions from the native habitat to highly invasive species instead.

A lot of people don’t know that mule deer exist on Catalina, but they do know that bison have also been introduced. Why are the bison not as controversial? Bison are slightly less problematic because their population be easily controlled through birth control. Also, they do not browse on the native, endemic vegetation as much as the deer. They are grazers, preferring grass and weedy material over shrubbery.

As on other islands, native species exhibit strange characteristics, with small species evolving to be larger and large species miniaturizing. One such example is the island ceanothus. Its leaves are large and soft, leading to its common name “feltleaf ceanothus.” When compared with the mainland variety, which has small, leathery leaves, which type do you think the deer prefer to eat?

To protect native habitat, conservation staff have constructed exclosures to keep deer out. The difference between plots of land thus protected and those not is starkly apparent, especially at this time of year. The exclosures are filled with lush, green vegetation adapted to the boom-and-bust cycles of precipitation on the island. Additionally, the abundance of healthy lichen on the shrubs within exclosures shows the importance of fog (and fog catching) to the native island plants. Outside of the exclosures, tan, dry, invasive vegetation predominates. Much of the dry, brittle material you see across Catalina are invasive plants, which tend to take over in disturbed places. The same is true here as on the mainland: native vegetation is more fire-resistant. But despite their adaptations to recover from fire, these plants will lose out to "type conversion" and be replaced by fast spreading invasives if burnt too often. What's too often in this ecosystem? More than once every 100 years.

But exclosures are not foolproof - bison can easily breach them, so they need to be patrolled and repaired regularly. These are a simple but highly effective tool in protecting some of the rarest plants in the entire world, including Catalina Ironwood, with only about 115 in existence. Another plant on the island, the Catalina mountain mahogany, is critically endangered and has only 6 members living in one spot in the wild. When a population gets this small, it enters a genetic bottleneck that makes it less resilient and adaptable. There is still time to save these species, but the clock is running out.

A lot of important work is being done at the CIC’s native plant nursery at "Middle Ranch" on the island – seeds and cuttings collected from the wild are tended to with expert and loving care. Some of the rarest are being held in trust here until they can be reintroduced to the wild, but until the deer have been removed, restoration cannot happen in earnest.

Removal of the deer from the island is proving controversial, with improbable partners in opposition - animal rights activists and hunters are banding together to advocate for the persistence of the mule deer in this ecosystem. Simply reducing the size of the deer population through increased hunting has proven ineffective - after the last hunting season, when more take permits for the deer were issued than usual, the does responded with a bumper crop of young to replace the culled individuals, giving birth to twins or even triplets!

The issues that CIC face are familiar to VLT – from the proliferation of invasive species to threats to native vegetation, the ongoing and mounting effects from climate change, and human pressures, including human-induced wildfires, we share many concerns.

To learn more about the ongoing restoration project on Catalina Island, please visit the CIC’s website at https://catalinaconservancy.org/restoration-project/ To learn about the work that Ventura Land Trust is doing locally, please visit our website at www.venturalandtrust.org