Friday, April 15 8:30AM - 6:00PM
Impact of the invasive amur honeysuckle (lonicera maackii) on stand transpiration in a wetland forest. Richard L. Boyce1, Richard D. Durtsche1 and Joshua Shouse1. Northern Kentucky University1
Amur honeysuckle is an invasive shrub found in the Ohio River Valley that excludes native plants from areas that it invades. Its effect on water use by a wetland forest in Kentucky near the Ohio River was determined during the summer and fall of 2009. A mature forest stand was compared with a second-growth stand on the St. Anne Wetlands Research and Educational Center in Melbourne, KY. While the mature stand had a very sparse shrub canopy, the second-growth stand had a dense Amur honeysuckle cover. Shrub basal area was more than 5 times greater in the second-growth stand, and >85% was honeysuckle. Transpiration rates from trees were similar in the two stands. Shrub transpiration from the mature stand was only 1.9% of tree transpiration (10% due to honeysuckle) but 9.1% (6.6% due to honeysuckle) from the second-growth stand. Shrub transpiration was dominated by honeysuckle in the second-growth stand. Because of its extended leaf-out period, honeysuckle continued to transpire late in the fall, when tree and native shrub transpiration has ceased. Honeysuckle transpired the equivalent of ~10 mm of rainfall in the second-growth site over the monitored period, whereas it transpired the equivalent of ~1.9 mm in the mature site, a > 5-fold increase. The additional transpiration caused by Amur honeysuckle may shorten the lives of ephemeral ponds and streams in wetlands, with adverse impacts on organisms, such as amphibian larvae, that require them.