Hide and Seek in the Creek – Coverboards

By: Paolo Solari

Coverboards have been used in amphibian and other terrestrial vertebrate studies for many years, and can be a great way to determine which animals are present in an area. Coverboards offer suitable nest sites for terrestrial vertebrates (mostly amphibians) and offer protection from predators. They also are useful in that they reduce nesting-site competition. With all this in mind, we thought that coverboards would be a great way to determine what kind of animals, as well as how many, were in our very own backyard in Copeland Creek. Unfortunately, things did not go quite like we had planned. I’ll talk about that a little later, though. First of all, here is what we did:

Our first step was getting coverboards. Wendy helped a lot with that. In fact, she bought us 8 of them! The next step was to distribute them (relatively) evenly throughout the length of Copeland Creek on campus. Our plan was to place two coverboards in each section of the creek. Danielle and I lugged the 8 coverboards to the eastern end of the bridge near the footbridge, where we placed our first coverboard. Despite occasionally getting stuck in those pesky Himalayan Blackberry bushes, we made our way westward down the creek, towards the ETC building. Our goal was to place the coverboards in cool, moist locations. We also thought it would be best to hide them as much as possible to avoid potential disturbance from larger animals or people exploring the creek (this would end up making it somewhat difficult to find all of the coverboards). After we placed all of our coverboards, our next step was to wait for critters to move in.

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Photo source: Paolo Solari

Two weeks later, Beverly and I checked the coverboards on a foggy Monday morning. We slowly lifted the first one, only to find the ground underneath completely uninhabited (save for the occasional tiny arthropod). Despite finding no signs of amphibious life under our first coverboard, we did not lose hope. However, this desolate trend continued all the way to our very last coverboard, in which we found nothing but a couple of pill bugs.

 

Before starting our experiment, we knew that most coverboards need at least three months to establish (and can sometimes take up to a year). Obviously we were working with a much shorter time frame.  Our mindset going in was that we most likely would not find anything, and that turned out to be the case.  However, we still learned sampling methods that we would not have learned otherwise, and that is not something that we take for granted. It was also nice to more intimately familiarize ourselves with our own backyard in Copeland Creek, a place that we have, and will continue to spend a lot of our time.

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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.