Science for a Blue Planet

Featuring cutting-edge work, discoveries, and challenges of our scientists, our partners, and the larger conservation science community.

Learning About a Vital Ecosystem – From Below the Ground Up

Early rains have fallen on the sweeping Jenner Headlands, on the coast of northern Sonoma County, and the ground here is softening. For a team of ecologists at Point Blue, this is the cue to launch a second field season in our Rangeland Monitoring Network (RMN). For the next six months, at dozens of properties across California, they will take the pulse of ecosystem health.

Rangeland spans nearly 40% of California’s area and holds immense importance for people (all of us!), as well as for wildlife and for livestock. How well does the living layer of earth perform the vital functions of storing water and holding carbon in the ground? Through the RMN we are finding out, for the first time, at scales relevant for conservation.

By measuring soil characteristics and assessing biodiversity in the same places, we are building a valuable new baseline of knowledge. Today, and continuing through the wet season, the focus is on the soil itself.

Libby Porzig with some of the tools used for scientific sampling of soils. Photo by Wendell Gilgert/Point Blue.
Libby Porzig with some of the tools used for scientific sampling of soils. Photo by Wendell Gilgert/Point Blue.

Measuring the Soil’s Vital Signs

“In 2015-16 we’re aiming to sample at 200 points,” says Elizabeth (Libby) Porzig, PhD, who leads the Rangeland Monitoring Network. “This will more than double our sample size from our first season.”

During the winter months, the RMN team will focus on soils to analyze their compaction and carbon content. Later, in early spring, they will gather data on plantlife at the same points. In June, during birds’ breeding season, they will complete the data set by counting the birds detected—a good indicator of biodiversity.

Monitoring the same points in future years will produce measures of changes in the soil ecosystem. Rangeland soils, if managed properly, have the potential to increase water and carbon storage capacity. This is because healthy, functioning soil is naturally loose and crumbly, often due to the strong fibrous roots of native perennial plants that penetrate deep and improve conditions for the many soil organisms.

Practices by land stewards make the difference, and increasing numbers of ranchers and land-trust managers are eager to make use of the RMN results. Complementing our Rangeland Watershed Initiative, the RMN will furnish data that can guide increases in soils’ water-holding capacity—in a region vulnerable to drought.

Tools of the Trade

For the day’s field work at Jenner Headlands, Libby and two Point Blue colleagues, Ecologist Ryan DiGaudio and Partner Biologist Suzie Winquist, park on a road inside Jenner Headlands Preserve and carry their gear to the first sampling point. The Wildlands Conservancy manages this preserve, in part with grazing practices, and actively partners with Point Blue.

Arriving on foot at the first sampling location, the three biologists set their day packs and implements on the ground and begin gathering data and samples.

To measure carbon content up to 40 cm deep, we obtain samples using a special probe. Photo by Ryan DiGaudio/Point Blue.
To measure carbon content up to 40 cm deep, we obtain samples using a special probe. Photo by Ryan DiGaudio/Point Blue.

First comes the rate of water infiltration into the soil—its capacity to receive precipitation. They pound a plastic cylinder two inches into the soil, fill it with a standard amount of water, and time how fast water soaks into the ground. This reflects on the soil’s inherent capacity to allow water to enter the ground (versus mostly sheeting off), improving conditions for carbon capture and the ability of the ecosystem to sustain life.

Next they extract samples of soil to measure for compaction and for carbon. Ryan pounds a small steel pipe into the ground to obtain a precise quantity of soil. Later, in a work space provided by TomKat Ranch, the Rangeland Monitoring crew will weigh this sample, then dry it thoroughly and weigh it again. Its weight is a measure of the soil’s density. Less compacted soil has spaces within it where more water can penetrate, creating vast capacity for water retention in the ground.

Finally the team uses a long cylindrical probe to extract a continuous column of soil 40 cm long, intended for laboratory analysis for carbon content. The roots and decaying bodies of plants transfer carbon taken from the atmosphere deep into healthy soil. Management practices that favor perennial plants can enhance this vital capacity for removing a greenhouse gas from the atmosphere.

Multiple Benefits

The promise of rangelands is not just in the soils and water and carbon-holding capacity; it is in the multiple benefits these lands can provide, with proper management. The benefits include food production, of course, but also diverse plant and animal life that provide a multitude of services such as pollination, seed dispersal, and insect control—not to mention pure beauty and inspiration.

Scientific data are the key to protecting and increasing these benefits. The data collected by the RMN can reveal what works, where, and when—all critical to managing complex agro-ecosystems in a future where we will depend on functional and resilient land more than ever.

Learn more about the Rangeland Monitoring Network.

Also see the summer 2015 Point Blue Quarterly.

And read more about the morning at Jenner Headlands in the 12/24/15 Point Reyes Light.