Problem Species

Manuel Hernandez and Julianne Bradbury

Most problems are relative, right? In an urban creek like Copeland Creek, certain species are bigger problems than others. The Restoration Ecology class at Sonoma State has detected a whole spectrum of problem species living in and around the creek that might not be obvious until you learn about them.

The most common way for a species to cause problems is to be “invasive” – an invasive species reproduces profusely and outcompetes other species, reducing or even eliminating them from the local environment. This common threat to biodiversity can come in either plant or animal form, and in Copeland Creek it comes in both of those forms. First, we took a close look at the creek banks and surrounding area for plant species that threaten the quality of the habitat. Second, we set some clever (and exceedingly gentle) “traps” to discover what some of our most adorable problem predators are up to.

One of the most common and easy to spot invasive plants in Sonoma County is Himalayan blackberry (Rubus armeniacus), a strong, fast growing shrub with wicked thorns and delicious berries. Another common perpetrator is fennel (Foeniculum vulgare), an aromatic plant with fluffy, dissected leaves and  tall flower stalks. Many other invasive plants found in Copeland Creek are ornamental plants that have escaped from landscaped areas on the Sonoma State campus; these include maytens (Maytenus boaria), tree of heaven (Ailanthus altissima), plums (Prunus spp.), black locust (Robinia pseudoacacia), and eucalyptus (Eucalyptus spp.).

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Fennel is a common invasive plant in Sonoma County, CA. Photo by Stanley Spencer, 2009.

 

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A close-up of the rigid stalk and impressive thorns of the Himalayan blackberry plant, a major invasive species in Copeland Creek, Rohnert Park, CA. Photo by Zoya Akulova, 2009.

Before we can begin to control the populations of invasive plants in the creek, we needed to document just how widespread they are – this will help us determine how successful our removal efforts have been from year to year. We moved slowly but surely along the banks of Copeland Creek over 4 days in October 2016, estimating the percent cover of Himalayan blackberry and noting the presence of every species of invasive plant we could identify. We used this data to generate maps depicting the state of invasive plants along the SSU campus reach of the creek, which will be used to track the successes of our restoration efforts for years to come.

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Domestic cats are one of the largest threats to small mammal and avian biodiversity. Even well-fed house cats will kill animals simply to kill. To assess the cat population we joined with the two other groups using wildlife cameras, and Tony Nelson from the Sonoma Land Trust who kindly loaned us five cameras and taught us how to set them up.

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Tony Nelson Demonstrating the Proper Way to Set Up a Wildlife Camera. Photo by Wendy St John

We selected four locations, one in each zone and set the cameras to take three pictures, one every three seconds, per trigger event. The cameras were left out for a 72 hour period before being collected.

Our first cat was seen in Zone 2, and only appeared in one of the three photos.

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An overexposed picture of a Blurry Cat. Photo by HCO SG550

Again in Zone 2 we captured what looks like the tail of the same cat.

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The tail of a Cat. Photo by HCO SG550

The camera in Zone 3 captured a black cat in two separate  trigger events within the same day.

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While we did not capture many cats on our cameras, we do know that cats use the creek regularly and future camera traps left for multiple, longer periods could show a much larger population.

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