Phenology - Studying Plant and Animal Life Cycles

By Tom Greco, Communications Specialist

An acorn on one of Pepperwood's many oak trees

It is autumn at Pepperwood. Deciduous trees like black, Oregon, and blue oaks are all losing leaves. Squirrels and acorn woodpeckers are busy gathering acorns – the latter stuffing them into their granary trees. Our big leaf maples, found along creeks and seeps, are turning a brilliant yellow. Ravens are foraging on figs at our homesteads by the dozens. Bucks are shedding their summer camaraderie and beginning to scuffle for dominance as rutting season begins. It is a great time to examine phenology.

Phenology is the study of plant and animal life cycles and biological events as they are influenced by environmental factors like changing seasons, variations in climate over time, and localized elements like soil composition and elevation. If there is unseasonably little rainfall one winter, for example, that may affect the life cycles of certain plants. They could experience a later bloom than average, or perhaps produce less seeds that year. If a plant blooms late, that could in turn affect the life cycle of an insect that relies on it for food. In this way, phenology can also be used to examine the relationships between plants and animals within their environments.

Examining a budding plant to determine what life cycle
stage it is in.

The study of phenology is not new, but it is becoming increasingly important in the face of our changing climate. As average annual temperatures and other climatic factors begin to shift, they will undoubtedly affect the life cycles of plants and animals. In order to measure the impacts of a changing climate, a baseline for current temporal patterns of biological behavior must be established. This means taking regular observations of life cycle events like bud burst in plants, or the first appearance of butterflies or migratory birds or animals. Over time we can determine the correlation between shifting climatic factors and phenological responses in our flora and fauna.

Dr. Susan Mazer explains the California Phenology Project's 
monitoring protocols to Pepperwood staff and volunteers 

Because of the great diversity of plant and animal life, especially in our region, collecting phenological data can be a time consuming and labor intensive process. Fortunately, advances in technology have made it much easier for researchers to collect this data with the help of citizen scientists, who are often nature-enthusiasts volunteering their time. The California Phenology Project (CPP), which was launched in 2010 with funding from the National Park Service, was created to help streamline the collection of phenological data by offering resources and creating a central database where organizations and individuals can contribute their work. Dr. Susan Mazer of UCSB, founder of the CPP, visited Pepperwood in August to advise on Pepperwood’s current monitoring program and how it can be tied into the CPP.

Many of Pepperwood’s research efforts, including our Vital Signs monitoring project, involve the study of phenology. Each year we collect data via our Reptile and Amphibian Survey, Grassland Monitoring, and Acorn Monitoring projects, to name a few. This year, we are working with the Santa Rosa Junior College (SRJC) to apply for funding from the National Science Foundation for a long-term Phenology Project at Pepperwood that is aligned with protocols set by Dr. Mazer and the CPP. This is the focus of SRJC student Prahlada Papper, Pepperwood Steward and the inaugural Stephen J. Barnhart Herbarium Intern, who is working with Pepperwood staff to establish a transect model that could be replicated in other locations throughout our region.