USC Dana and David Dornsife College of Letters, Arts & Sciences > Blog

July 28, 2012

On the Trail

Filed under: Uncategorized — Tags: , , , , — judithfo @ 8:48 pm

Last Thursday, we were able to make significant progress on our Deer Valley Trail projects. We finally got our hands on the necessary supplies, including cement and flags for our plots. We were able to dig almost all the holes for the informative trail signs. The interns from last year had written and designed them, but getting them in the ground proved to be a challenge for us, as the soil was incredibly solid and we lacked the proper tools. However, we were able to use heavy metal rod to create holes deep enough for the signs. The first one was successfully mounted into the ground using cement.

The same day, we also accomplished a lot for our fennel project. After obtaining and processing the soil samples the day before, we began the fennel treatments. To ensure the plots were random we picked papers out of a hat for the three treatments (full removal, mowing, and a control). The different treatments are designated by a different color flag in the middle of each of the plots. For the full removal, we used shovels and grubbers to break the fennel at its taproot, which will prevent it from growing back. This is the primary method used by the Catalina Island Conservancy. Full removal is the most effective method but can result in soil disturbance and requires intense manual labor. Because of this, we are also looking at the effectiveness of mowing. To mow the fennel, we used pruners to cut the fennel stalk as low to the ground as possible without disturbing the taproot. Mowing will almost always result in fennel re-growth, but we are looking to see if mowing continuously once a year will eventually kill the plant. We did not touch the control plots. We had two of each treatment at each site, totaling to four plots per treatment type. We also decided to take additional soil samples from under native plants so that we can already have a comparison in nitrogen levels before the summer ends.

We felt a sense of accomplishment in finishing one of the major steps in our project. After this, we will be taking soil samples once a quarter to monitor the soil nutrient levels and observe any changes. Most likely, next year’s summer interns will resume the project and continue with the annual mowing.

Top: Judy Fong mows a plot using pruners. Photo credit: Dawnielle Tellez. Bottom: Dawnielle performs full removal of fennel. Photo credit: Judy Fong

 

We hope to not only unlock interesting answers regarding how different fennel treatments affect soil nutrient levels, but also to provide a consistent project for future Environmental Studies interns to build upon. The trail will serve as a field lab for classes and groups. The class ENST 320A: Water and Soil Sustainability will be utilizing the trail as a platform to perform soil samples in the future. For example, one of the ENST 320A field trips to Catalina could process the soil samples for that quarter and contribute to our data. In addition, the restoration project should provide experience removing fennel and other invasive grasses, watering, taking more soil samples, and potentially some seed or root collection. We hope that our work with the fennel project and restoration project will help allow for learning opportunities and hands-on experience for students. We expect that this trail will be getting more and more use as time goes on. Whether it be through the informative signage or the restoration site, we hope that our efforts will make a lasting impact on whoever uses the trail in the future.

 

Editor’s note: The ENST Catalina Island Internship at USC Dornsife is offered as part of a summer internship program offered to undergraduate students in theUSC Dana and David Dornsife College of Letters, Arts and Sciences. This course takes place on location at the USC Wrigley Marine Science Center on Catalina Island. Students investigate important environmental issues such as ecological restoration, protected-area planning and assessment, and invasive species management. During the course of the internship, students will work closely with USC faculty and staff scientists from the Catalina Island Conservancy to support ongoing conservation and management programs being implemented on the island. Instructors for the course include David Ginsburg, Assistant Professor of Environmental Studies, Lisa Collins, Lecturer in Environmental Studies, and Tony Summers, Invasive Plant Program Supervisor from the Catalina Island Conservancy.


 

July 9, 2012

Invasive Plants

Filed under: Uncategorized — Tags: , , , — sholle @ 10:29 pm

Environmental problems are complex entities which take a broad set of skills and understanding to properly address and mitigate. On Catalina Island three interns and I from USC are getting experience working with various conservation organizations seeing firsthand what it takes to properly preserve valuable and productive ecosystems. Last week we worked with Peter Dixon who is in charge of the native plant nursery on Catalina Island. From the early morning until the late afternoon we spent our time touring various ecosystems around Catalina Island looking for California Locoweed (Astragalus trichopodus var. lonchus), Vernal Barley (Hordeum intercedens), Fragrant Pitcher Sage (Lepechinia fragrans) and Black Sage (Salvia melifera). When we found the flora species of interest our group harvested 10% of the seed from each plant and counted maternal lines in order to keep track of the genetic diversity. All this work goes toward maintaining a viable seed bank, which is necessary for restoration and the retention of native and endemic species on Catalina. One of the species, Hordeum intercedens is a relatively rare grass on the island and proved to be especially difficult to locate given the abundance of similar invasive grasses.

Above: USC students survey a watershed on the east side of Santa Catalina Island. Photo Credit: Stephen Holle

Seed collection is especially important because grasses like H. intercedens face an immense amount of competition from invasive grasses, which often times have more dense and broad distributions. Invasive grasses are one of many environmental problems on Catalina Island because their biomass contributes large amounts of nitrogen to the soil, which further promotes the spread of invasive plants such as fennel. A possible explanation for the persistence of invasive species on Catalina Island could be due to the increased influxes of nitrogen from invasive grasses and other plant species. As Peter Dixon explains, “native and endemic grasses on Catalina are typically found in dispersed distributions while invasive grasses have higher and broader population densities.” As a result long term “plant invasions increase soil nitrogen pools and total ecosystem nitrogen stocks” (Rout 2009) and contributes to invasive plant success and rapid colonization around the island. Given these ideas about nitrogen influxes and the spread of invasive plants my fellow interns and I are developing a short term project in order to understand the spread of invasive plants using applied conservation. Although our time is limited on Catalina Island, we look forward to establishing baseline studies for future continuation.

Works Cited:

Rout, Marnie. “An Invasive Plant Paradox.” Science 324. (2009). 734. Online.

Editor’s note: The ENST Catalina Island Internship at USC Dornsife is offered as part of a summer internship program offered to undergraduate students in the USC Dana and David Dornsife College of Letters, Arts and Sciences. This course takes place on location at the USC Wrigley Marine Science Center on Catalina Island. Students investigate important environmental issues such as ecological restoration, protected-area planning and assessment, and invasive species management. During the course of the internship, students will work closely with USC faculty and staff scientists from the Catalina Island Conservancy to support ongoing conservation and management programs being implemented on the island. Instructors for the course include David Ginsburg, Assistant Professor of Environmental Studies, Lisa Collins, Lecturer in Environmental Studies, and Tony Summers, Invasive Plant Program Supervisor from the Catalina Island Conservancy.

June 30, 2011

Scientific Diving

Filed under: Uncategorized — Tags: , — drkasang @ 3:41 pm

While the work we are involved with through this internship is terrestrial, Sabrina and I are scientific certified divers. In order to stay certified I need to perform 12 dives each year otherwise I will no longer be considered a scientific diver. Today Jim Haw, head of the ENST department, and Mariah Gill came out to Catalina to dive. Sabrina and I decided to join them on their dives for the day, one at Bird Rock and one at Isthmus Reef both locations I had not previously dived. As we were assembling our gear to get out in one of the skiffs, Gerry came up and said he needed a volunteer for a working dive. I was quite jealous when Sabrina snagged the opportunity to perform her first working dive.

I felt better once I was in the water and saw a thick cover sea grass. We descended along the anchor line to make sure we were secure and found we needed to embed the anchor further into the sea floor. Mariah set about securing the anchor and a startled sea hare inked nearby, surrounding us in a fluorescent  purple haze. Once it was properly secured, Mariah took lead on the dive pointing out lobsters, a horn shark and all sorts of sea life. She has a knack for taking her time in the water and finding the most interesting things. I noticed a harbor seal that was swimming around the kelp near us, checking us out but never getting too close or staying in one place long enough for me to show Mariah and Jim. It ended up being a very enjoyable dive that got us back to Wrigley with just enough time to grab lunch at the mess hall.

Our second dive at Isthmus Reef proved to be much more challenging. Since Mariah and Jim were planning on taking the afternoon Miss Christi back to the mainland, the planned dive was expected to be much shorter. However, once Jim was in the water, he checked the anchor and found that it wasn’t secure and Mariah was going to need to stay in the boat since she was the only one who had completed her BoatUS course. We performed a 20 minute dive along the reef, weaving through kelp and we even had enough time to find a moray eel. When we returned to the boat Mariah told us that she couldn’t pull up the anchor, so we descended along the line and found a huge mess of kelp. The leaves were so thick that I could hardly see a few inches and quickly got wrapped up in kelp. After getting free I found Jim using his EMT shears to free the anchor. By the time we were back in the boat with the anchor Jim and Mariah had to scramble to get on the boat before it left at 3:30.  Overall it was a fantastic day of diving with the ENST crew that had a few surprises. In my limited experience diving, most of which have been in Big Fisherman’s Cove, every dive is a new experience with something different to see or a new challenge to overcome.

Article by ENST professors about Guam

Article by the Daily Trojan discussing the work of this years students

Student Blog about Guam and Palau in Scientific American