Note! This field trip has been postponed to Wednesday, March 11th
What to see: Vernal pools are some of the most fascinating and increasingly threatened wetlands in California. They are seasonal, meaning that they have standing water in part of the year, and are dry during the summer and fall months. The interesting thing about them is that every year there is a seasonal progression of plant communities, given that most of the species are annuals. The plants that thrive in the standing water are replaced by those that germinate and grow as the soil begins to dry out. Then, later in the summer, these are replaced by species that “prefer” the driest phase in the summer and into fall. But that’s not the only type of plant “partitioning” that occurs! There is also a spatial separation of plant communities at any one time of the year. This is especially obvious during the early spring months, as the pools gradually dry. Some species grow best and most abundantly in the deeper parts of the pools, others in the areas that are slightly “upslope” from the bottome, and still others at the upper parts of the pools at the boundary with the never-inundated uplands.
When we visit the “Mather Pools” in February, they should still be inundated and we’ll be able to see aquatic plants that like the wintry “wet phase” of the pools, including water starwort (Callitriche species), spikerush (Eleocharis macrostachya), and, perhaps, even the rare legenere (Legenere limosa). We’ll also be able to see the beginnings of early spring upland plants; perhaps even some blooming shooting stars (formerly Dodecatheon, now included in Primula)!
Difficulty: Easy. We will be wandering among the pools and spending time at them, sifting the water with our fingers to find the little aquatic plants. There are no restrooms available at the Preserve, but restrooms can be accessed at the nearby Mather Regional Park.
What to bring: Water, snacks/lunch, insect repellent, sunscreen. There is no shade, so you might like to have a hat.
When: Wednesday, February 18, 10 am – about 1 pm.
Please fill out a form for each individual interested in participating in this field trip.
