PARENT SESSION
Poster Session 20: Invasive Species
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Delayed vegetation release seven years after removal of bush honeysuckle (Lonicera maackii) in southwest Ohio.
Runkle, James*,1, DiSalvo, Angie2, Graham-Gibson, Yolanda1, Dorning, Monica1, 1 Wright State University, Dayton, OH, USA2 World Forest Institute, Portland, OR, USA
ABSTRACT- Lonicera maackii is thought to inhibit growth of herbaceous vegetation and woody seedlings. To determine the extent of this inhibition a paired removal/control experiment was conducted. In April 1996, Lonicera was removed from ten 30x30 m areas within Sugarcreek Reserve, located near Dayton, southwest Ohio. Paired 20x20 m plots were established, one of each pair in the removal area and one adjacent to that area. These plots varied in history and topographic position. Twenty 1x1 m small plots were established in each large plot and sampled for herbaceous vegetation (by species and cover class) and woody seedlings (species and number). Sampling was done summer 1996 and spring 1997. Nine of the paired plots were resampled using the same techniques in summer 2003 and spring 2004. For the spring samples, few differences were found between control and treated plots the first year after Lonicera removal: the response (establishment and growth) of the ground layer was not immediate. Significant differences between control and treated plots had occurred seven years after treatment. Total percent cover per small plot was 37.4% with Lonicera and 74.5% without. The number of species per small plot was 4.1 with Lonicera and 7.8 without. Woody seedlings in all plots totaled 105 with Lonicera and 326 without. Summer samples after removal were similar. Few immediate differences were found. However, after seven years the removal plots had 53% more plant cover overall (significantly different overall and for 6 plot pairs), more medium-sized (30-100 cm height) woody seedlings (23 total versus 3 in plots with Lonicera), higher Simpson's diversity values (0.82 vs 0.59) and more species (average 3 more species per big plot). Species composition, based on ordinations, still was more similar between paired plots than overall between plots with and without Lonicera. These results indicate that Lonicera removal can enhance ground layer species diversity and cover after a lag period of at least one year. Further, the results indicate that Lonicera regrowth is slow in closed forests so that removal can be done at moderately long periods (at least seven and probably ten or more years).
Key words: invasive species, shrub impacts, management