Scripta Varia

The Center for Plant Conservation model to urgently and effectively conserve North American plants

John R. Clark[*]


From food to medicine, from clean air to clear water, to intrinsic beauty and the very landscape that covers our planet, plants define the human experience. Plants provide overwhelming benefit to the planet, regulating global water and air cycles, cleaning the soils, and shaping the environment in ways conducive to human health and longevity. Despite this indispensable and multifaceted role in our lives, plants are remarkably undervalued. Nothing accentuates this neglect more than the sheer number of plants that face extinction.

The value of plants

It is widely known that plants provide an essential backbone of ecological support for our planet, maintaining the quality of life we enjoy today (see Raven, this volume; Smith, this volume). Plants clean Earth’s air, water and soil and maintain global nutrient cycling, among many other benefits commonly referred to as ecosystem services (Ehrlich and Mooney, 1983). Plants are vital to fundamental aspects of these ecosystem services, and maintaining plant diversity is proven to positively enhance these services including provisioning of plant products, erosion control, invasion resistance, pest regulation, pathogen regulation and soil fertility regulation, in addition to the aforementioned services (Quijas et al., 2010). Plants thus directly affect overall human health and provide the foundation needed to mitigate the effects of a burgeoning human population with its increased land use and overall environmental degradation including climate change (Haines-Young & Potschin, 2010; Raven, this volume).

Further concerning quality of life, plants form the foundation of modern medicine and human nutrition. Plants have been a primary source of medicines since prehistory, a trend that continues extensively today (Petrovska, 2012). Even in this century, 11% of the ~250 essential drugs recommended by the World Health Organization are of flowering plant origin (Veeresham, 2012). Foods are also fundamentally plant based and even those that are animal in origin are inherently dependent on plants. Plant-based diets have been overwhelmingly proven to be both the healthiest for human consumption and beneficial to the environment, often eliminating carbon loss and waste associated with animal-based diets (Spingmann et al., 2016). Numerous studies support plant-based diets as correlating strongly with a lower frequency of major illness in humans including cancer, heart disease and diabetes (Hever, 2016).

An increasingly recognized importance of plants is the intrinsic value they bring to our quality of life. Studies in recent decades illustrate well that nature, and in particular plants and plant-dominated landscapes, provide much needed health benefits (Keniger et al., 2013). Conversely, deprivation from natural environments has been shown to increase stress and related psychological and physical disorders, although research is ongoing (see Keniger et al., 2013). The effects of this depravation are so profound that it has been given a formal name, nature-deficit disorder (Louv, 2005). Psychologists, physicians and other medical professionals are actively researching the benefits of plants to our well-being, including those in urban areas, as a result (see Shanahan et al., 2015, e.g., Tiffert et al., 2015).

Plant loss – current estimates, cause and regional challenges

Despite the aforementioned value that plants bring to our lives, we are losing plant species at an alarming rate. According to the recently published report from Royal Botanic Gardens, Kew on the State of the World’s Plants (2017), as many as one fifth of all plants on the planet, or an estimated 80,000 kinds of plants, will be extinct within the next century if current trends continue. Others estimate even higher rates, owing to under estimates of plant diversity in the tropics where narrow endemism is high and habitat destruction is perhaps most rampant (e.g., Pimm and Joppa, 2015, Pimm and Raven, 2017, Raven, this volume).

The causes of these dramatic declines in plants are multifaceted and include population and resource consumption, habitat loss and climate change. At current rates of consumption, the world’s 7.5 billion people are consuming unsustainably, thus requiring increased land use and associated environmental degradation. Consumption is critical and mitigating these effects requires managing consumption rates and their effects on species loss (Chaudhary & Brooks, 2017). In developing regions, particularly the tropics, deforestation and overall habitat conversion continue to be a primary driver of species loss today (Watson, et al., 2016). Climate change, too, is substantially implicated in species extinctions and thought only to accelerate as trends continue (Raven, this volume).

Regionally, these collective challenges plants face are easily seen. Consumption, habitat conversion and climate change have been demonstrated in numerous studies to threaten species globally, but particularly affecting vulnerable ecosystems such as islands, coastal environments, alpine regions and Mediterranean habitats. In the United States and Canada, here defined as North America north of Mexico and including the US outlying states and territories of Hawaii, Guam, American Samoa, Puerto Rico and the US Virgin Islands (the primary regions addressed in this paper), the loss is particularly pronounced. 

Of the approximately 17,000 kinds of plants in the US and Canada, an estimated 4,400 kinds are ranked as critically endangered by NatureServe, the authority on species conservation assessment in this region (A. Francis, pers. comm.). Beyond these critically threatened species, more common species are also being threatened as land use and fragmentation continues, with new and emerging diseases, and with invasive plants and animals all threatening the overall plant diversity and ecological stability of this huge swath of planet Earth. It is clear that urgent and effective means to save these species are needed (see the Global Strategy for Plant Conservation for further justification in saving plant diversity around the world).

The Center for Plant Conservation – a model for collaboration

To address the overwhelming need in the US and Canada to save plants from extinction, the Center for Plant Conservation was founded in 1984 with the guiding principal that plant conservation experts must come together to make a meaningful difference in preserving plant diversity for future generations (White, 2005). At the time it was recognized that considerable expertise was evolving among disparate organizations in the US and Canada and yet communication between these experts was limited. CPC was founded to bring these professionals together to share ideas and advance the science and practice of saving plants. This early CPC was comprised of ten institutions; today it has grown to over 60 organizations representing some of the world’s best gardens, arboreta and conservation research organizations as well as environmentally committed, for-profit companies. Principally focused in the US, CPC Participating Institutions (PIs) and their conservation professionals are many of the world’s experts in plant conservation. Using cutting-edge methods and the best science available, CPC Conservation Officers as they are known, do the hard work of saving plants for future generations.

CPC’s mission is simple and proven: to ensure stewardship of imperiled native plants. CPC is a one-of-a-kind network that collaboratively works to save the imperiled plants of the US and Canada. CPC PIs maintain the CPC National Collection of Endangered Plants, a living conservation collection of imperiled plants, by working to collect and manage living collections of seeds and plants for the long-term survival of these species and used to enhance and sustain wild populations as required. In particular, CPC PIs work to advancing our understanding of threats as well as means to save these species and, by communicating with partners within the CPC network, ensure that all are using the best and most up-to-date means possible to save imperiled plants (Center for Plant Conservation, 2019).

Greater than the sum of its parts, the CPC network saves more plant species together than would ever be possible alone. This is done through the timely sharing of information, data and expertise, and facilitated by the community of practice that is CPC where the world’s experts regularly convene to discuss and apply methods that result in far greater numbers of plants saved from extinction.

CPC focuses efforts using the following tested and effective strategy:

·    Advance science-based best practices in plant conservation through the CPC network of conservation partners known as Participating Institutions.

·    Apply these practices to Save Plants from extinction in North America as part of the CPC National Collection of Endangered Plants.

·    Share best practices with conservationists the world over and advocate for plants and their value to humankind.


To date, the Center for Plant Conservation and its network now have over one third of the US and Canada imperiled plants (~1,500 of 4,400 kinds) secured in the CPC National Collection. Active research programs in dozens of CPC organizations are all working to overcome conservation challenges for the remaining two thirds. Challenges such as seed storage, plant propagation and preservation/recovery of species in the wild, are all being addressed by these CPC partners (Center for Plant Conservation, 2019).

CPC’s model of collaborative work with a shared responsibility to save plants has been used as the basis for other national and global efforts. The CPC guidelines (Center for Plant Conservation, and authors therein, 2019), developed over decades of intensive collaborative work, are currently used by these organizations and plant conservationists around the world to save plants.

CPC is now focused on creating better means to bridge the gap between scientific advancements and applied conservation outcomes. To this end, the CPC team is working on a new web-based data sharing and conservation information platform known as Plant Nucleus. Plant Nucleus is the redevelopment of CPC’s website into a go-to online resource community where CPC partners engage to save plants from extinction. This cloud-based community was born out of the need to better communicate and share best practices to address questions in ways that work for conservation professionals.

In looking at how CPC could serve the conservation community better, it was realized that the current conservation system was not set up to address conservation questions in ways that are both effective and efficient. It was also recognized that making data available in ways that increase knowledge and make conservationists better at saving plants was required. Plant Nucleus ideally will do all this by providing a one-stop resource where users are able to choose how to both use and share data. This freedom will ideally increase how fast knowledge is shared and will let conservationists focus on saving more plants. Time will tell if this approach will be successful.

Conclusions and future directions

Plants provide tremendous benefit to humankind and the planet. Through regulating environmental cycles to providing essential resources for human health and happiness, plants are key to our very survival. However, global trends tell a story of under-appreciation and neglect for plants worldwide. Rates at which we are losing plant species are alarming; these trends affect every country on earth including the US and Canada where as many as one fourth of native plants of these two countries face extinction.

The Center for Plant Conservation has proven to be an effective model of collaboration, being a network of plant conservation professionals focused on saving the most imperiled species within a chosen region. With a core focus on advancing the science of saving plants, and through developing and implementing clear means to communicate these emerging best practices, CPC has managed to effectively conserve over one third of the imperiled plants in their target countries of the US and Canada.

To build on this success, more focus needs to be placed on bridging the gap between new discoveries and conservation outcomes. Too often we hear that new insights are not effectively shared or methods being used are outdated. Still other instances of duplicated work on the same species have occurred, resulting in wasted resources at best and with potentially negative outcomes for the species at worst. What is needed is a better means to share information, within a framework that works for those saving plants, and a system that inspires adoption and use.


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[*] Ph.D., President and CEO, Center for Plant Conservation, 15600 San Pasqual Valley Rd., Escondido, CA 92026, USA;; 760.291.5486.




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