Protecting California’s Renowned Plant Diversity

By Andrea Williams

Last year, the California Native Plant Society formed a new staff division: the Biodiversity Initiatives Group, a team focused on stewardship, horticulture, community science, and best practices for ecological land management. Andrea Williams is directing the group as California faces its greatest threats to biodiversity in modern history. Here we begin a new series with Andrea focused on California’s plant diversity and the strategies needed to protect it.

Sky lupine (Lupinus nanus) and oak woodlands in Santa Rosa, CA Photo: Marlin Harms

In 2020, Gov. Gavin Newsom issued an ambitious executive order aimed at biodiversity protection, climate resilience, and equity. Importantly, it called for these three attributes in tandem, not isolation. 

Climate change is the dominant environmental story of our time, and the state of California is rightly turning to nature-based solutions to reach its goal of carbon neutrality and climate resilience. By now most people are familiar with clean energy approaches to limit the degree of climate change, but fewer talk about managing lands for carbon sequestration, or the other interrelated pillars necessary to protecting quality of life on this planet: biodiversity and equitable access to nature.

Living in a Biodiversity Hotspot

California belongs to one of the world’s 36 biodiversity hotspots. It has more native plant species than any other state in the U.S. – a third of which are found nowhere else on Earth. We are lucky in California, but we also have a lot to lose. New research from NatureServe and The Nature Conservancy shows that California has the highest concentration of imperiled species of any state in the contiguous U.S.  Biodiversity here at home is in peril, and Californians of all backgrounds and skills must come together to protect and steward it.

For some time, California’s leaders have given voice to biodiversity protection but failed to provide the necessary investments and implementation infrastructure, particularly in historically marginalized communities where resources and thriving green spaces are needed most (see maps below). Today, California has a chance to change that, starting with its goal to protect 30% of its lands and waters by 2030 and an ambitious new plan. Here’s what we need to get there:

    1. A durable definition of conservation that includes restoration and science-based land management

      California’s 30% conservation target is part of an international effort, most commonly known as 30×30. The state’s 30×30 plan aims to promote climate resilience and equitable access to nature’s benefits. But for conservation to be meaningful, it must have strong criteria and permanent protection. The California Natural Resource Agency’s “Pathways to 30×30” report indicates that conservation must be durable, and conserved lands must have a mandate of biodiversity protection. Currently these criteria limit inclusion to lands under a conservation easement or with a Gap Analysis Program Status of 1 or 2. A Gap Analysis for biodiversity looks at both location data as well as conservation status. Levels 1 or 2 indicate better protection – broadly, national or state parks, wilderness areas, Areas of Critical Environmental Concern, and natural reserves. However, these criteria are currently self-reported and do not necessarily represent the status of biodiversity in conserved areas.

      Science-based management includes not just nature, but also access and infrastructure placement and maintenance to ensure biodiversity is protected. Biodiversity conservation is an active process, and science-based land management and restoration takes funding; our natural areas have long been starved of appropriate investment. The National Park Service catalogs and quantifies its maintenance backlog, but we need similar efforts for our natural resources. California’s state parks have a $1 billion maintenance backlog, without a sense of resource management needs, and the “burden” of additional areas added to the system has often been used as a reason to not conserve more places.

    2. Scientific investments in strong systems of inventory and monitoring

      In order to save plants, we need to know where they are. This principle holds for biodiversity as a whole: how many species, in what proportions, and where/how they need to move to connect populations or in response to climate change or other stressors. Basic inventories–fine-scale vegetation maps, rare species, and key biodiversity areas–are needed as a point of reference, a snapshot in time, and can be combined with community science efforts such as bioblitzes for a granular and broad-based picture of plants across the landscape. Current status can be compared to previous records where available, and used as a benchmark against which to measure future change.

      Long-term monitoring efforts like the CNPS Carrizo Plain Grassland Monitoring tell us about changes in a population or plant community over time. In areas where management aims to alter vegetation, monitoring is always necessary for adaptive management: the cycle of understanding the system you are manipulating and its response to your inputs. It’s the monitoring equivalent of “How it started/How it’s going” and we need so much more of it as California undertakes millions of acres in vegetation treatments to reduce wildfire severity, or invests billions in restoration and climate adaptation. So often, the work in natural areas is summarized by dollars and acres. These are measures of effort, not effect, and give no insight into whether we are succeeding or not.

    3. A Focus on plants

      When we save plants, we save everything else. Plants form the foundation of our ecosystems, but too often they are under-represented in data sets and subsequent conservation.

      Plants are essential to life and crucial in measures of biodiversity, yet they are not well-included in the state’s measures of biodiversity such as Areas of Conservation Emphasis. The Important Plant Areas Program addresses the need for a model of plant diversity across the landscape that includes rare and common species, important vegetation, and culturally significant plants. Community science programs such as Fire Followers and Rare Plant Treasure Hunts mobilize volunteers to help track wild plants in numbers unreachable by the usual scientific monitoring. These many lines of evidence combine to form a better picture of biodiversity in California.

    4. A Commitment to equity and tribal sovereignty

      People are part of nature. For communities and landscapes to be healthy and resilient – to withstand disease, drought, and rising temperatures – we need nature to be diverse and accessible. A glance at maps showing the distribution of communities of color and protected areas shows very little overlap. Redlining and siting infrastructure isolates people from nature and its benefits, and slices through natural communities as well. Biodiverse green spaces in urban areas allow plants and animals to move, connecting all for mutual benefit.

      Our current network of protected lands was created by the removal of Indigenous people, and Indigenous erasure continues today as tribes are often prevented from practicing their cultural burning and other tending and gathering on public lands. This is changing in some places, but efforts to protect and manage biodiversity would do well to recognize that California’s biodiversity is the result of millenia of active stewardship, and that areas important to protect biodiversity often overlap with culturally important sites. Movements including land back, and supporting Indigenous stewardship, are essential to biodiversity protection.

The map on the left shows the percentage of the population that’s people of color (from EPA; warmer colors=higher percentage) and on the right showing the distribution of protected areas (from CANature; blue and green are considered conserved under 30×30). Even with rough graphics, we can see the disparity and lack of overlap.

Saving is just the start

What’s where, and how it’s faring, are questions that underpin not only conservation but also restoration and stewardship. Locations may need saving in the form of land protection, invasive species removal, or native planting. But conservation is only where we begin. California’s biodiversity owes strongly to millenia of stewardship by Indigenous peoples, and tools such as burning, cutting and digging remain necessary today to maintain our state’s abundance. It’s also not just our wild spaces that need care; native plants in the built environment have tremendous potential to support local diversity as well. Tools such as Calscape help support decisions around what to plant and where, whether you’re gardening for pollinators or landscaping an office building to save water. Community science involves people in recording and understanding the state’s biodiversity, monitoring changes on the landscape from fire or management or inventorying natural areas.

CNPS is the voice for plants at a time when it’s needed most: Conjoined crises of climate change, extinction, and affordable housing shortages present dire risks for California’s native plants and all the life that depend on them. Without a focus on plant biodiversity, we risk destroying millions of acres of habitat in the name of wildfire prevention; we trade intact habitat for clean energy development; we build communities indiscriminately. We all lose if we settle on either/or when we need biodiversity, clean energy, and shelter to survive – and thrive. By understanding where biodiversity is concentrated, we can choose the right places to build and the right places to protect. By funding sustained monitoring, we can be sure we’ve got it right. By transforming our built landscapes, we can help heal the damage already incurred.

This is the aim of the new CNPS Biodiversity Initiatives Group, formed last year in recognition of the active role people can take to document, support and promote California’s plant biodiversity. BIG is a solutions-based team, focused on supporting communities, decision-makers and land managers with science-based guidance to meet 21st century challenges. 

Andrea Williams, CNPS Director of Biodiversity Initiatives


  1. Volunteers will need to be part of the solution even more than they have been. There is not enough money to manage and restore today’s inventory of preserved open spaces. Training is also essential much like what the San Diego chapter’s restoration group does.

  2. Is there any partner program with state parks and open spaces? It would be a great opportunity to archive the 30×30 goal

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