Pyrrharctia isabella, North of Glacier Peak High School

Pyrrharctia isabella

The Wooly Bear

The forest north of Glacier Peak High School was my chosen location. It is primarily a hilly area, sloping down toward the Snohomish River Valley, with lots of undulating terrain covered in rotting pine needles, maple leaves, logs, sword and bracken ferns, mushrooms, and various shrub species. The taller trees were those you generally find around Washington: Red Cedar, Dougles Fir, Hemlock, and lots of Maple. An access road for the forest service and sewer maintenance runs down the south side of the portion of forest I explored, and it was enclosed on either side by the invasive Himalayan blackberry, the small shrub species, young conifers, young Alder, and grass. There are many fallen trees and tree stumps that are nourishing new life, and the ground is downright squishy with water and rotting plant matter, but I did not see any active or dry streams. There were very few rocks or boulders in the area I surveyed. One interesting thing I found was an apparently abandoned tree fort that someone was building, complete with tools lying where they were last left, and several trees hewn down to form posts for the platforms. I also found a dead rat covered in flies, but no other animal life besides insects.

 

This is the access road where I conducted my survey of Wooly Bears. 

A rotting log

A mushroom feasting on maple leaves.

A tree feasting on a rotting stump

Unfinished Fort

Tree they chopped down

 Dead Rat

Mushroom and fern

For my population study, I chose Wooly Bear Caterpillars. I found a total of three Wooly Bears across the 12 quadrants, which were separated by ten steps each. On average, there were .25 caterpillars per quadrant. Quadrats 1, 3, and 10 had one Wooly Bear each. This transect may not be entirely representative of the site because the terrain was so uneven and difficult off of the access road, that doing a straight transect inside the woods would be significantly harder, though it may yield more Wooly Bears. This sampling tells us that Wooly Bears are more commonly found at the beginning of the transect, which started slightly farther into the woods. I would say this is a single population of Wooly Bears, because they are tiny little animals, and they do move. I am unable to determine if terrain altered the distribution of Wooly Bears; they were all found on the access road, which had little variation. I noticed while I was doing the transects that one or two Wooly Bears were to the sides of where I had to put my quadrat to make a straight line, and I had to desperately resist moving the quadrat or Wooly Bear to alter the results.
If surveys like this were conducted in an area, and the various habitats and terrain types within the area were able to be factored in to an estimate for the species population, this could be a very effective way of estimating populations of creatures without having to go out and manually count a thousand Wooly Bears. For threatened and endangered species, with even stricter necessary habitats than your average caterpillar, if we know that an ecosystem is capable of hosting __ number of an endangered species, we can estimate how many there might be, and alter our assessment and recovery efforts accordingly.