Restore Habitats

Building Biodiversity

From wildlands to agriculture to our backyards, native plants provide many essential services to humanity, such as pollination, clean air and water, and soil conservation. Ecosystems with a wide range of native plant species are better able to provide these benefits and to recover from disturbances such as fire, flood, and drought. From microbes to mammals, we are all tied closely to native plants.

Invertebrates as indicators

Knowing plant-invertebrate relationships can help us to recover<br />
rare plants and restore habitats. Here, a Diadasia chimney bee<br />
takes refuge from the wind and rain in the flower of a golden-spined<br />
cereus (Bergerocactus emoryii) on San Clemente Island We often use terrestrial insects, arthropods, and other invertebrates as tools to guide our conservation efforts. These groups are incredibly diverse, often useful for assessing differences between degraded and intact areas, and play key roles in ecosystem processes such as nutrient recycling, pollination, seed dispersal, and energy flow. The networks between plants and invertebrates are crucial to food webs that support larger organisms like reptiles, birds, and mammals. Terrestrial invertebrates also respond quickly to environmental change, and provide an indication of restoration progress.

Three projects illustrate this work. First, on San Clemente Island, a terrestrial invertebrate survey has allowed us to also assess pollinator networks for rare plants, reveal affiliations with different habitats, and provide a repeatable baseline dataset that will allow us to assess future changes and responses to management actions. Next, on San Nicolas Island, our comparisons between plots invaded by the South African invasive crystalline iceplant (Mesembryanthemum crystallinum) and uninvaded habitat have revealed significant impacts to arthropod species richness, composition, and functional diversity – with negative implications for the island fox (Urocyon littoralis). Our subsequent restoration experiments explored the best ways to regain the native plant diversity needed to restore these assemblages. Finally, on Santa Rosa Island, repeated comparisons between cloud forest habitat undergoing restoration and more intact areas will both reveal progress and determine the best methods to recover these communities. The suite of invertebrates associated with native species and habitats could hold the key to ecological resilience and self-sustainability.

Restoring native habitat after fire

Bush poppies (Dendromecon rigida) are a native fire-following<br />
species that thrive in the first few years after a burn,<br />
shown here in the Thomas Fire Scar Fire is a natural and cyclical disturbance in many Southern California habitats, and many native plant species are well adapted to respond to fire through underground burls or seeds that are stimulated by fire. However, fire disturbance also represents an opportunity for non-native invasive species to establish, and increasingly frequent fires may reduce the ability of native vegetation to recover. We’re using vegetation surveying, spatial modelling, and experiments to identify where and how to restore fire-affected ecosystems.

In 2017 and 2018, Garden staff and volunteers investigated two ‘botanical black holes’ (little-surveyed areas) in the Los Padres National Forest: the Zaca Fire (which burned 240,207 acres in 2007) and Jesusita Fire (which burned 8,733 acres in 2009). Currently, the Garden is continuing these efforts with a project surveying in the Thomas and Whittier Fire scars with data-gathering help from community scientists. To learn about this and past work, or to get involved in the Thomas and Whittier Fire project, you can check out our Fire Recovery and Community Science page.

In addition to surveying and prioritizing areas to restore, we’re also studying how to best conduct restoration. Among these projects are a collaboration with Hana Restoration to remove Spanish broom and restore native species seeding along East Camino Cielo, and an upcoming study of the whole-ecosystem benefits of restoration in the Piru fire scar.

Controlling invasive plants to protect the rare ones

The sunny yellow flowers of the Vandenberg monkeyflower (Diplacus vandenbergensis)<br />
are threatened by the invasive African veldtgrass (Ehrharta calycina). We are working to understand the best way to control this grass to benefit the monkeyflowerThough they have limited distributions and are often in small populations, rare plant species are ecologically significant members of their habitats. However, one of their greatest threats is invasion by aggressive non-native plants. We are using experimental projects to better protect two Federally Endangered plants in our region from this threat: salt marsh bird’s beak and Vandenberg monkeyflower.

The salt marsh bird’s beak (Chloropyron maritimum ssp. maritimum) is a pretty purple parasite that is restricted to upper salt marsh habitats in southern California, where human development has pushed it out of 60% of its former range. European sea lavender (Limonium duriusculum) not only takes over bird’s beak habitat, but we have also found that it supports European honey bees instead of the native bees that bird’s beak relies on to reproduce. We’re experimenting with lavender removal at the University of California’s Carpinteria Salt Marsh Reserve, in collaboration with Tidal Influence, to bring back not only the bird’s beak, but also the bees.

The sunny yellow flowers of the Vandenberg monkeyflower (Diplacus vandenbergensis) light up the bare ancient sand dunes that it occupies on the Burton Mesa in Lompoc. One of the greatest threats to this rare annual wildflower is African veldtgrass (Ehrharta calycina), which forms dense hardy clumps where native plants used to mix and mingle, and is rapidly taking over the California central coast. We are conducting an experiment on the Burton Mesa Ecological Reserve (owned by the California Department of Fish and Wildlife, and funded by the U.S. Fish and Wildlife Service) to determine the best way to control this plant for maximum monkeyflower recovery.