Wednesday, May 1, 2013

Understanding Pepperwood's Mushrooms

By Prahlada Papper, Pepperwood Steward

Helvella lacunosa
The kind of warm, dry weather we’ve seen throughout inland Sonoma County this past winter isn’t usually associated with mushroom foraging, but research on mushrooms (a.k.a. “foraging for data”) continues regardless. In order to document the effects of climate on mushroom fruiting, we need to do surveys during the dry seasons as well as the rainy ones. All that data is equally valuable to a complete picture of fungal ecology.

In fact, though, several groups of mushrooms continued to be surprisingly abundant at Pepperwood throughout January and February even with less than 5cm of accumulated rainfall, including elf saddles like the Helvella lacunosa seen in the picture to the right. That one is growing in a redwood grove, but another species, Helvella maculata, has also been common under Douglas-fir along with several species of Inocybe while live oak dominated forests have been mostly devoid of mushrooms.

Understanding patterns like theseof when and where mushrooms appearis the goal of a study recently revived here at Pepperwood using existing plots that had been sitting ignored and nearly forgotten for almost 15 years. Between 1996 and 1999, David Melloy, a graduate student at Sonoma State University, conducted regular surveys of mushroom diversity on the preserve using the same plots that we were surprisingly still able to re-locate after all these years. Several of those original plots were re-flagged and a few new ones were established in order to continue David’s work of studying the fungal diversity in Pepperwood’s forests and help clarify how localized climate, soils, and vegetation affect that diversity across a varied terrain and through both long and short spans of time.

From the wet and drippy Fall, to this dry and warm Winter, and now into the late Spring that we can only hope will bring rains again, our team has gathered and identified mushrooms from the plots and measured the trees surrounding them to put together spatial maps of each plot.

Combined with regularly collected data on temperature, humidity, and soil moisture, this study can help us answer basic questions about forest ecology and climate change. The appearance of mushrooms is being used as a token of the many organism-organism and organism-environment interactions that create an ecosystem.

Mycelium seen in a soil cross-section
Fungi spend most of their lives as networks of microscopic filaments in the duff layer or within the wood of fallen logs where they are among the primary decomposers of dead plant material. Or in some cases fungi form symbiotic mycorrhizal relationships with trees and plants in which a fungus helps supply water and nutrients to the plant while extracting the carbohydrates it needs to survive from the plant’s root system. At some point, environmental cues that are still not completely understood—but certainly include temperature, moisture and nutrient availability—can prompt that nondescript subsurface tangle of fungal cells to begin the fruiting process, leading to an above-ground mushroom. So fungi, and in particular their mushrooms, are uniquely suited to making many obscure environmental processes and patterns more evident. They may even be a key indicator of changing climate from year to year.

This particular mushroom study at Pepperwood Preserve will hopefully continue on for many years, generating a large enough batch of data that the more complex and long-term patterns behind the fruiting of the different mushrooms can begin to emerge from the background noise of a dynamic forest system.

This mushroom study is among the growing group of long-term monitoring projects at Pepperwood open to citizen scientist volunteers. Experience in ecological research is not necessarily required.  If you’d like to help on any aspect of the study—from fieldwork collecting mushrooms or surveying trees to lab work preparing soil samples or preserving voucher specimens—contact Pepperwood staff to be added to the project’s mailing or volunteer list. Work continues, rain or shine!

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