Today was our last day in the Wild Davis class (sad face!) and today the students presented their final projects! We structured it as a little mini-conference, complete with snacks and sparkling juice (in actual wine glasses) for a classy little event. A short description (and photos!) of each students’ project is outlined below:
Arboretum Waterway: Turbidity and Secchi Depth (Anne Boyd)
Anne’s project related to water quality throughout the Arboretum waterway, measured using secchi depth and turbidity. A secchi disk estimates water quality through clarity – the deeper the disk goes in the water before you lose sight of it, the clearer the water is. Turbidity assesses the ‘cloudiness’ of the water by measuring particles suspended in the water column (like small algae). Professor Steven Sadro in Environmental Science and Policy loaned Anne the equipment and some bench space in his lab for the data collection! Anne hypothesized that water quality would be highest near the weir (since that was one of the reasons for the construction of the weirs) and lower as you move down the waterway away from the weir to more stagnant areas of the waterway. She found instead that the clearest location in the waterway was near the southwestern end, her second furthest site from the weir. She developed some new hypotheses to explain her unexpected data, including the impacts of runoff and point source inputs, shading by trees, and the ‘inputs’ of ducks, fish, and turtles.
Anne also contributed my hands-down favorite photo from the class. I met up with each of the students during their individual projects to observe their data collection. After taking turbidity samples, Anne totally unprompted did the one thing people always want to photograph scientists doing – holding up a vial of liquid and looking at it very intently.
The quintessential field science photo
The Wildlife of Davis: A Coloring Book (Ella Brydon)
Ella’s project was quite different from the other students’. Her ‘question’ related to how to get the general public (particularly other UC Davis students) interested in the wildlife of the Arboretum and the ecological interactions we had observed in class. Towards this goal, she developed a coloring book of Arboretum wildlife based on her own original drawings of organisms found there. Each page of the coloring book is accompanied by the scientific name, as well as interesting facts and identifying information for that organism, and color sketches of many of the organisms are included in the introduction to guide the colorer. We plan to print a couple bound copies of the coloring book and we may approach the Arboretum and the campus bookstore about a larger-scale printing effort to make the coloring book available to students.
Squirrels, Squirrels, Squirrels! (and ducks)
Three of our students did projects on the squirrel population on campus. As even the most casual observer has noticed, there are MANY squirrels on campus. What they might not have noticed is that there are two species of squirrel – the fox squirrel (orangeish and commonly found around the MU), and the western gray squirrel (gray, and more common in the Arboretum area). The fox squirrel is introduced, while the gray squirrel is native.
Harrison Espino observed squirrel behavior at different locations, focusing on whether interactions with humans were active (approaching or fleeing) or passive (unresponsive) and how far individual squirrels traveled during his observation window (up to 45 feet in 20 minutes!).
Nia Falkner compared tameness of squirrels and ducks on campus, noting how close individuals would let her get and their reactions (vocalizations, tail flicks) to her approach. Nia’s presentation included a particularly tame duck quacking along to Nia’s rendition of “Just the Two of Us”!
Lisbeth Solis tracked foraging behavior in squirrels, particularly whether they were searching for food or begging from humans. She found that squirrels in the MU spend a much larger amount of time begging for food, while squirrels in other locations almost exclusively search on their own.
Insect Preference for Sugar and Salt (Xinyu Gao)
Xinyu was interested in attracting flying insects to liquid solutions, based on her enjoyment of butterflies from her hometown. She put out tap water, 1% salt solution, and diluted honey and tracked insect visitation from late morning to after sunset. She found an interesting variety of organisms (more than just the insects she expected) including carpenter bees, flies, spiders, moths, and even a cat…. All of the baits experienced much higher visitation after dusk and the sugar bait had the highest visitation (salt was the lowest).
A Study of Camponotus essigi (Isabelle Gilchrist)
Isabelle was inspired by our afternoon with Phil Ward and decided to track ant behavior she had noticed around Robbins Hall Annex. She observed ants moving up and down a tree trunk and into and out of Room 12 of the Annex. Attempting to gain access to Room 12 to determine where the ants were going led her on a wild goose chase across multiple departments, and even emails with higher admin! No one was able to answer her questions, or even unlock the door. Consequently, Isabelle reported that the room ‘belongs to the ants now.’ Keeping to the outdoor behavior, Isabelle attempted to ascertain if the ants were going into our out of the door and up or down the tree. She counted numbers of ants moving in each direction and collected some for weighing. She also photographed ants foraging and documented the relative abundance of major and minor workers. Her data indicate that ants coming down from the tree were heavier (presumably carrying food in their stomachs back to the colony) and that about 25% of the ants were worker ants. She also hypothesized that all ants around Robbins Hall Annex are part of one colony, since transporting ants from her area to a separate colony on campus resulted in attacks between the ants (which were not observed between ants traveling on/around the tree and the Annex).
Which Trees are Best for Nesting? (Laura Poikonen)
Laura observed bird and squirrel nesting site choices in the Arboretum. She noted that squirrels and birds both prefer angiosperm trees, particularly ones with fuller foliage cover. She also noted that birds and squirrels do not use the same individual trees, perhaps because of nestling predation by squirrels. Laura also got some fabulous photos of bluebird nest holes in trees, which she took with her cell phone through the lens of her binoculars!
Balance Coming From Under Us: Decomposers of UC Davis (Abigail Rodriguez)
Abigail’s project focused on the underground communities of decomposers on the Davis campus. She compared litter composition and decomposer type and abundance at different soil locations around campus, finding that the more managed areas with landscaped lawns had no macroscopic decomposers at all. At more ‘natural’ locations throughout the Arboretum, a wide variety of organisms were found, including ants, earthworms, spiders, millipedes, and beetles.
Finding Otter (Tristan Tran)
From the first day of class, Tristan was intrigued by the rumors of otters inhabiting the Arboretum waterway. He hoped to find one himself, so to guide his search, he developed an online survey about otter presence and behavior. He also spent time in the Arboretum looking for the otters himself and distributing the survey in person to others present in the Arboretum. While he did not find any otters during these observations, the findings of the survey were very interesting. Tristan compared survey responses of otter behavior and diet to published research. There was no consensus among the respondents on when otters are most active (they are mostly crepuscular) and little on their preferred habitat, identifying pretty much the entire waterway as ‘most likely habitat’. Most respondents believed otters used to be present in the waterway, but have left it recently due to draining of the waterway for construction and repair, or because of changes in water quality. First hand observations of otters were usually at least two years in the past (and most were four or more), which supported the assumption that the otters are not currently present. Many respondents (and Tristan himself) hope/believe that the otters may recolonize the waterway now in the coming years. When asked if he plans to continue his otter search throughout his tenure at UC Davis, Tristan responded that he spends a lot of time in the Arboretum for a variety of reasons, and will keep an eye out for the otters whenever he is there.
I had an absolutely fantastic time in the Wild Davis class this quarter. Sharon and I had a great bunch of students who were all motivated and excited to get outside and do class a little differently each week. They had great ideas for their projects, really followed through on the data collection and analysis, and produced awesome papers and projects. Numerous students even asked us if it was ‘ok’ to go over on the length of the paper! I hope the students enjoyed the class as much as I did, and I really look forward to offering this class again in the future. Until next time…. keep it wild, Davis!
Laci M. Gerhart 
[…] After the mid-day observation, I made the Pond a formal Place in iNaturalist so I could easily track what wildlife has been found there. Consequently, I arrive at the Pond about 7:30 on Monday evening with a couple goals: 1) bypass Greg Ira (Cal Nat program coordinator) as the top observer at the pond and 2) observe a river otter, which have been documented in the Pond by both Greg and iNat user natewl. I casually inquired with some colleagues and Greg is totally unaware of our ‘competition’ at the Pond, which makes meeting Goal 1 more likely. Both of the otter observations already posted were made around dusk in the spring, which makes Goal 2 seem likely, though I am well aware of how elusive otters can be. […]