2008

The project was initiated in 2008 by students in the Tropical Rainforest Program of The Evergreen State College, 8-13 March 2008.

The project was designed to measure the effect of a modification of the Winkler method. Normally a miniWinkler sample is taken by chopping a meter square area of forest floor with a machete and then immediately sifting the chopped material. This sifted material is later hung in a Winkler bag for extraction. We asked whether chopping and then waiting a while before sifting would alter the sampling efficiency, as measured by number of species per plot. We also wanted to know whether chopping would attract army ants, with the prediction that plots with a delay between chopping and sifting would have a higher incidence of army ants.

On 10 March we took 60 miniWinkler samples. Six groups of 3-4 students were stationed at 50m intervals along the upper part of Trail #13 (8.40831 -83.32742), which is an area of primary forest. Each group laid out a transect due west (the trail runs roughly north-south) and took 10 miniWinkler samples at 5m intervals. Each group had five samples that were chopped at about 8am and then sifted at about 10am (2 hours later), and five samples that were chopped and sifted during the second time interval. Thus the actual sifting took place at about the same time for all samples, the only difference between the two groups being that one was chopped 2 hours before sifting and one chopped immediately prior to sifting. The order of sample treatments was randomized within each sifting group.

The samples were carried down to the station and hung in miniWinkler bags that afternoon. They were left to extract for three days, after which samples were bagged and returned to the Longino Lab at Evergreen. Students in the lab sorted all the ants from the samples. Longino then identified the ants in each sample. The results are based only on workers (species for which only queens were found were ignored). Also, a scattering of Crematogaster erecta, a dominant arboreal ant on the scaffolding where the samples were hung, occurred in the samples. These were all assumed to be contaminants and were discarded.

A report of the results can be found here.

Sixty MiniWinkler samples at Osa Biodiversity Center, hanging in miniWinkler bags.

The 2008 Tropical Rainforests class: Amber Carver, D. J. Cox, Christine Davis, Oren Grimm, Katherine Halstead, Edward Holbrook, Jameson Honeycutt, Molly Hukari, Kira Kranzler, Ryan Kruse, Benjamin Lee, Aimee Machiels, Neal Marks, Corrie McAliley, Sarah Michel, Amber Mount, Michelle Olsen, David Peterson, Samantha Price, Nick Smith, Jessica Starrett, Kendra Steadman, Lauren Troyer, Adam Wicks-Arshack (Faculty and staff: Paul Butler, Melquisedec Gamba-Rios, Jack Longino).

The sample-sorting group, left to right: Brittany Broyles, D. J. Cox, Jesse McAlpine, Duke Brady (far right Jack Longino).