As is the case with sharks, spiders and other infamous threats that confront outdoor adventurers, poison oak elicits more scorn than it deserves. In fact, given the important roles the plant plays in natural ecosystems, it deserves nothing less than our sincere appreciation and respect.
While Pacific poison oak - known to botanists as Toxicodendron diversilobum; provides a variety of benefits to natural ecosystems, the following three benefits are particularly noteworthy
1. It Provides Habitat for Animals
- Poison oak does not appear to cause negative effects for many animals; most traipse through it with impunity. This enables a variety of small animals to use the plant's leaves and stems as habitat. Insects and other invertebrates lurk under the shade provided by the plant's broad leaves, while lizards and frogs hunt these very same insects from within the tangled stems and vines.
- Chipmunks, squirrels and other rodents scurry to and from their burrows underneath carpets of poison oak, safely concealed from predators by the thick leaves. Birds even use the plant as a place to get out of the sun or to build nests and raise their young.
2. It Nourishes a Wide Variety of Species
- Poison oak also serves as a food source for a number of animals. Several insect species, including a variety of butterflies and moths, feed on the leaves, as do deer and squirrels. The leaves not only provide calories to these hungry herbivores, they also provide them with calcium, phosphorus and other important nutrients. Their flowers also serve as a food source for beetles and bees, who spend their days sipping the nectar tucked inside.
- The berries are an important food source for a variety of bird species. Not only do the pale green or white berries provide the birds with a nutritious snack, their tendency to persist on the plant through the fall and early winter provides birds with an important resource when times are tough.
3. It Competes with Invasive Species, Limiting Their Spread
Many parts of California - and, indeed, the rest of the world - are waging a battle against invasive plant species. Plants like giant reed and bull thistle have colonized the land, and altered the habitats significantly.
- Here again, poison oak saves the day, as it can outcompete many of these invasive species, thereby denying them of a home. Poison oak is particularly helpful in this regard, as it is the most widespread shrub in the state and it is capable of surviving in a wide variety of soil types and growing conditions.
While it is important to understand the benefits poison oak provides, it can cause serious illness in humans, so respect is warranted. Given the stakes, it is imperative that outdoor enthusiasts learn to identify poison oak to stay safe. But remember, just because this plant can be troubling for humans, doesn't mean that it isn't a crucial component of the ecosystems to which it is native.
By Ben Team
Ben Team is a lifelong environmental educator and ISA-certified arborist who writes about the natural world.