Ben Keller, Molly Robertson, Justin Nickolaus
Lisa Ely (Other), Dan Beck (Biology)
Lichen Coverage on North- and South-Facing Slopes in Central Washington
Lichen are symbiotic organisms that live on trees, rocks and other surfaces. For our research we wanted to know if the direction the slope faces affects the growth rate of lichens in central Washington. Previous research has indicated that UV-B exposure reduces growth rates in some lichens. We therefore hypothesized that north-facing slopes would have a higher lichen coverage than south-facing slopes. To calculate the amount of lichen we laid down a transect line with a tape measure and measured the centimeters of lichen compared to the overall length of the transect. We had eight transects for both north- and south-facing slopes on Manastash Ridge south of Ellensburg. Our results indicated that the south-facing slopes had a higher percentage of lichen coverage than the north-facing slopes. The average lichen coverage twelve percent on the south-facing slopes and just under two percent on the north-facing slopes, causing us to reject our hypothesis. We believe that one reason why the south-facing slopes had more lichen was that very few rocks were found on the north-facing slopes, providing fewer surfaces for lichen growth. We conducted our experiment in the beginning of March, and there was still some snow on the north-facing slopes, which made the ground very saturated. The longer persistence of winter snow cover and greater moisture on the north-facing slopes could increase the amount of soil development, further reducing the exposed rocks for lichen habitat.
Keywords: LICHEN, SLOPE EXPOSURE, ROCK TYPE, diversity