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Mullein abundance along trails

Laura Crawford and Gaby Duong
Conservation Biology class, BIO 345, Biology Department, DePauw University
Fall semester 2013

Mullein is a non-native plant that grows in inhospitable areas.  It colonizes environments where other plants cannot survive.  Mullein is common in the Quarry Bottom of the DePauw Nature Park.  We observed that mullein seemed be more abundant along the edges of the Q1 and Q2 trails compared to areas away from the trails.  In this study, we quantified the distribution and abundance of mullein in the Quarry Bottom. 

We hypothesized that mullein would be more abundant along trail edges than in areas away from trails because the plant is more likely to grow in areas with more human activity and disturbance.

We mapped locations of rosettes (first year plants) and flowering (second year) mullein plants on the two quarry trails (Q1, Q2) and on four “shadow” trails.  The “shadow” trails were located in areas of the Quarry Bottom with no trails.  The substrate conditions (exposed rock, limestone gravel) were similar between the quarry trails and the shadow trails. 

We observed nine patches of flowering plants on the quarry trails.  There were more patches of mullein plants along the Q1 trail.  The densest patches of plants were on the Q2 trail.   Most of the flowering plants were located on the western end of the Q1 trail, close to the Quarry Pond.  We only found two plants along the shadow trails; both plants were rosettes. 

Mullein was more abundant along the quarry trails compared to areas with no trails.  Trails appear to have a significant effect on mullein populations.  Mullein seeds may be carried along trails in clothing and dog fur.  Higher disturbance levels, such as trampling, mowing, and gravel deposition, may also be contributing to the abundance of mullein along the trails.