Native Oaks: A Keystone Species

Keystone species are plants or animals that have a disproportionately large effect on the environment relative to their abundance. As with many of the trees here along the river, the oaks play a huge role supporting other flora and fauna.

Mammals like the Western Gray Squirrels (Sciurus griseus) love to eat acorns, making their nests inside oak trees where they’ll store their stash. You can often see these squirrels burying acorns around Lodi to save them for later. However, they can forget where they left them and don’t eat them, spreading the oak’s seeds!

Birds like the Acorn Woodpecker (Melanerpes formicivorus) also love eating acorns. The woodpecker collects acorns, drilling holes in a dead tree to store its acorns. These trees are known as granaries and can be used by multiple woodpeckers at once.

Larger birds like the Red-Shouldered Hawk (Buteo lineatus) might also perch in an oak tree, preying on the smaller birds flitting around in its leaves or smaller mammals in the dead leaves on the ground. These hawks also cache prey near their nest.

Other predators like the California King Snake (Lampropeltis californiae) might hide in the dead leaves, known as leaf litter, to stalk their prey. The stripes and bands on this snake help hide it from predators, allowing it to reach an age of up to ten years in the wild! Leaf litter also helps fungi like oak-loving Western Hardwood Sulphur Shelf (Laetiporus gilbertsonii) decompose dead wood, recycling nutrients back into the soil. Never eat any mushroom found in nature! They can be deadly.

Oaks also play host to fascinating insects. The Spined Turban Gall Wasp (Cynips douglasii) forms small, spiky pinkish galls on oak leaves to protect their eggs. Can you spot any?