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The National Park Service units that are participating in the California Phenology Project. Pilot park units are shown in dark green, and other participating parks are shown in sage green.

Phenology is the study of seasonal or periodic bio­logical events such as plant leaf-out and flowering, insect emer­gence, and animal migration. Put simply, phenology is the science of the seasons.

The phenological status of plants and animals across the seasons is dynamic and is closely linked to climatic and ecologi­cal variables. Consequently, tracking the phenology of plants and animals is a compelling way in which to study how living systems are functioning in response to climate variability and, over the long-term, to climate change.

Simple to observe and to record, phenology offers an intuitive approach for people in all walks of life to learn about the rhythms and natural processes of their local environment while observing directly the important links between the living world and the climate system.

In order to assess the effects of climate change on California’s extraordinary biodiversity and natural resources, the National Park Service (NPS), the University of California, Santa Barbara (UCSB), and the USA National Phenology Network (USA-NPN) have initiated The California Phenology Project (CPP). The USA-NPN is a national consortium of organizations and individuals that collect, share, and use phenology data to better understand resource responses to changing climates and environments (to learn more about the national effort, visit the USA-NPN). A full list of CPP cooperators and contacts can be found here.

With funding from the NPS Climate Change Response Program, the California Phenology Project (CPP) was launched in 2010 as a pilot project to develop and to test protocols, and to create tools and infrastructure to support long-term phenological monitoring and educational activities in California's National Parks. A primary focus of the effort is to recruit and to engage Citizen Scientists in the collection and interpretation of phenological data. On-the-ground pilot activities are currently focused in seven pilot parks (Redwood National Park, Lassen Volcanic National Park, Golden Gate National Recreation Area, John Muir National Historic Site, Sequoia and Kings Canyon National Parks, Santa Monica Mountains National Recreation Area, and Joshua Tree National Park; see map above); however, project products and infrastructure are being designed to support monitoring and educational activities for 19 California NPS units, other public and private lands in California, and National Parks in adjacent states. 

The CPP has had a very productive first four years. With guidance from dozens of California botanists and ecologists, the CPP identified over 60 plant species as high-priority species for phenological monitoring in California; these species were selected based upon their ability to encourage public participation, address key scientific questions, and inform natural resource management in California’s public lands (see the CPP focal plant species here). In 2011, the CPP mapped individual plants for phenological monitoring at all pilot parks, labeling for longterm and frequent monitoring >700 individual plants representing 30 species. Since February 2011, CPP observers and volunteers have contributed >850,000 phenological observations to the USA National Phenology Network database (  In 2012, the CPP began to expand the network of monitoring sites by working in the University of California’s Natural Reserve System, additional National Parks, and other public lands.