J. Rebecca Gould Calabro
August 7, 2005
This entry is actually the combination of several days work. I chose to include them all together because I felt that I wanted our research project experience to have some continuity separate from the rest of the course. In "real time" this project was completed in three days and this journal combines all the days so that it flows as a single research project.
The sunniest and driest part of Sweden finally lived up to its name. We switched the lectures and our projects so as to enjoy the clear blue skies. I chose to complete the project put forth by Stefan Andersson. Our task was simple --- Sample invertebrates using pitfall traps in two different localities and make comparisons between the tundra and the taiga habitats. In our group of four (Georg, Sofia, Lasse, and myself) we were to determine our question and implement the sampling experiment. It was determined that Sofia and Lasse would lay the pitfall traps in the alpine tundra and Georg and I would lay the traps in the boreal taiga. Our question was to look at the total biomass of the collected invertebrates as well as to look at the overall level of biodiversity.
In our groups, we discussed the procedure. This journal entry includes pictures of Georg and me completing the various steps. I did not like the fact that we were expected to kill the invertebrates by drowning them in the pitfall traps in a mixture of dishwashing solution and water. Unfortunately, if we did not use this step, the invertebrates would be able to crawl up the plastic cups used as the traps and escape. I decided that I have had quite enough bug bites to justify my learning about these creatures' habitat.
Georg and I decided to place the taiga traps this afternoon. We spent the better part of the morning in the wet lab (so named because of the use of messy organisms and chemicals) preparing the 40 pitfall traps. We had to make the mixture of dishwashing soap and water into forty separate vials labeled with our classification system. We decided to position two transects of twenty traps each. Both transects (a linear row of traps) would be in the same area but in two separate rows. We decided to put one transect on the lower side of a mostly dried up stream. The other transect was about 50 meters away on top of a boulder. Once we gathered our materials, we were able to plan our venture into the taiga.
We chose to walk about 2 kilometers into the taiga making sure that we stayed well within the tree-line. We chose a spot that was recognizable. There was a footbridge that crossed the swampy river that we would be able to remember. We now had to use the shovel to dig holes into the hard spongy ground. The holes needed to be about 3 inches below the surface --- enough so that the traps were completely under the ground. Invertebrates are actually quite smart. They can apparently see things sticking out of the ground and they might choose to walk around the trap instead of falling inside. Despite looking like the ground was mostly moss and shrubs, the soil was remarkably hard and very shallow. It only took a couple of seconds to reach the bedrock, and the end of that digging. This made it tricky since we often had to switch spots in the terrain simply to get an area where we could dig a hole large enough for the trap. We also had to keep each trap about 2 meters away from each other and in a straight line.
Nevertheless we were able to create our linear traps into the taiga soil. We then took the pre-made vials of soap solution and poured one vial into each trap. We did not have covers for the traps as rain was not in the forecast for the next 24 hours. We arranged the pitfall traps in two lines (or transects) --- one was placed near a boggy stream and the other was placed upon a low level boulder covered in vegetation.
Having finished what we could do, we opted to enjoy a hike through the taiga to observe the Abisko canyon.
24 hours later, we returned to our pitfall trap sites. We pulled up each trap and deposited the collections into a separate container labeled with the corresponding letter to the trap it came from. We returned immediately to the wet lab and spent much of the evening removing the soap solution from the containers and putting in alcohol to the specimens. We then allowed the vials to sit overnight until we would be able to identify our invertebrates and classify them into families.
Two days later we again were able to work on sampling the invertebrates into orders and families. I was assigned the task of determining what invertebrates had fallen into transect B (taiga). Georg did the same except with transect A (taiga). Lars and Sofia returned their samples to the wet lab but unfortunately did not keep each trap's specimen separate. Rather they combined their 1A and 1B together, and so on. This goes on to show how important communication is in science. Had this been a task done for the Beringia 2005 and the results critical in a comparison between Abisko invertebrates and Alaskan invertebrates, our data would now be null and void. Needless to say we continued the project as if the samples were stated and in my results section you will notice that Lars and Sofia's sampling efforts are preceded with the word "simulated."
Classifying invertebrates is tedious work especially when I have not been one who is known as having any love for insects. There were rewards though. Looking at spiders and mites through the microscopes was quite impressive. And did you know how large the mosquito (diptera) look under the microscope? No wonder those bites hurt so much! Regardless, each bug that was identified furthered the puzzle of who inhabits the taiga.
Transect B (taiga) yielded six different orders so species. I discovered 136 individual insects. The most common appeared to be the order Diptera, composed mostly of bi-winged flies. The second most common was the order Arachnia that are the spiders. Perhaps my most impressive vial was 19B that yielded a total of 19 spiders in it. I think that we must have placed the trap over a spider web or near it. One spider was considerably larger than the others. I felt slightly bad about having destroyed a spider family.
The final part of this project was to collaborate with my co-partners and make some sense of the findings. This information can be found in my written report that I had to complete as part of the Arctic Ecology project. I decided that the most useful way I could present this information was in a similar lab format that I would expect my middle school students to use. This way I can have my 7th and 8th graders repeat the experiment either at the school or on the Boston Harbor Island as well as have my Mentee's class also repeat the experiment.