July 12, 2011
Today was our second day of soil collection, and this time Lisa left us to our own devices. Our collection area today was the Two Harbors 2011 fire burn area and along Deer Valley Trail.
We started the day by gathering all of our sampling materials (spades, Ziploc bags, and transect tapes) and adding them into the “Bucket o’ Science” as Lisa lovingly calls it. We hopped in the van and drove back over to Two Harbors. I had scouted out some sampling areas the day before on my jog and proposed some ideas to the group. We decided to sample and transect an area that had burnt to a crisp, and an area in the same habitat that had not burned.
We set off up the hillside until we found a spot that was suitable, then set up the transect.
We attempted to identify some associated species of the area but it was extremely difficult. First of all, the only thing thriving in the area was invasive yellow mustard, which we had never formally identified. Secondly, all the plants that remained from the fire were grasses and were extremely difficult to identify. Instead of trying to guess each different grass, we decided to take a picture and take a sample to one of our experts and identify it later. It was a tough transect to complete and there was definitely a lot of discussion over each plant and each point.
As we were laying down the tape, we had a visitor join us. It was Wilson, Two Harbors’ resident bison! We were a bit scared as he walked toward us, but it turned out he just wanted to scratch his face against a bush nearby us. There are always so many neat animal encounters in the field, you never know what is going to pop out next!
Our next transect proved a bit easier, after a slightly treacherous hike to the sampling site. We wanted an area to contrast our burned site, so we looked for an unburned area. We climbed further up the ridge through a drainage, sort of following the road but mostly creating our own trail. Dan led the way and we found a great spot amidst some scrub oak. We completed the second transect, and took another soil sample. I really wanted another sample from the same aspect and elevation within the burn area (to have a direct comparison between burned and non-burned) so the group humored me and we hike across the hillside to the burned area to take a soil sample.
After lunch, Dan, Miller, and Alex went up to our trail in Deer Valley to complete another transect and take a soil sample.
Once the data collection was completed, Lisa showed us how to sift the soil in the bag using a two micron sifter. Sifting the soil is going to take a while since there are a lot of sticky clay minerals in this island’s soil. Even though it will be alot of work, I am excited to see how all of our samples turn out in the lab. Overall, it’s been a great experience working in the field.
For more photos see Soil Collection and Transects Part II
July 11, 2011
Today was our first day of collecting soil samples and transect data throughout Catalina. Lisa Collins came out on the morning boat with Lisa Chung and we took one of the Wrigley 13 passenger vans to Middle Ranch. We met up with Charlie who told us he had areas in mind that would be relevant to our study regarding soil in disturbed areas.
Our first stop was a riparian area not too far from Middle Ranch just along the road. We set up our transect by throwing the meter tape over the dense vegetation in the drainage. This was not my first time using a transect tape, but it was my first time using a transect tape on land which was a different experience. While this was fun to set up, collecting our data proved challenging because a large percentage of the vegetation was poison oak and thorny blackberry plants. After weaving our way through the plants we had assembled our data about plant coverage, recording species name and abundance, at 3 meter intervals and we collected our soil sample from the 15 m mark. After a quick lunch we ran a second transect perpendicular to the first which was much easier to collect our data and soil sample as there was less plant cover, especially poisonous ones.
After we compiled our data from the Middle Ranch area, we drove to a ridge near Avalon where the Conservancy has established an exclosure, to keep deer and other animals from getting to the plants within. These exclosures are particularly interesting because they are dominated by ceanothus arboreus or Catalina ceanothus. The difference in plant abundance and size was very obvious along our 2 transects. Although we haven’t seen the results of our soil analysis, it will be interesting to see if there is difference in the soils due to the presence of this plant. The exclosure had tall ceanothus covered in leaves whereas just a few feet away outside of the fence the same ceanothus were short with much smaller foliage.
To finish our collecting Charlie to us to an area of heavy Genista coverage and an area nearby where the conservancy had treated for these plants. Genista is a member pea family or Fabacea, a family which has root nodules that associate with symbiotic nitrogen fixing bacteria. This acts as a fertilizer for the plant. It will be interesting to see whether these Genista monocultures have an effect on total soil nitrogen as a result. Charlie “scree surfed” down the steep slope along loose soil and rocks to collect our soil samples and then just hiked right back up. After a long day of data and soil collection we headed back to the Wrigley Institute and stuck around for a stress-free dinner with Lisa cooked by the wonderful staff.