This post was written a few weeks ago, but never got published. Sorry.

Honeysuckle Rose was a song composed by Fats Waller in 1929. He must have been a conservation biologist, for honeysuckle and rose are the non-native invasive plants (NNIPs) most prevalent in Missouri.

In a previous post, I talked about what NNIPs are. I noted that they were most often deliberately introduced, but have escaped to dominate ecosystems to the point of destroying them. I noted that they cover an astonishing amount of land in America, they have large costs (that derive from economic damages they cause and the expense of trying to control them), and they are spreading.

Source: Moser, Hansen, & Nelson, The Extent of Selected Non-Native Invasive Plants on Missouri Forestland.

What about Missouri forests? Are they at threat from invasive species? The only way to know is to go look, and that is what scientists have done. The Northern Research Station of the U.S. Department of Agriculture has inventoried Missouri’s forest by establishing inventory plots throughout the state and examining them for the presence of 25 NNIPs.

Of the 1,264 plots of land examined, 530 (42%) had invasive species on them, consisting of 13 out of the 25 species looked for. Three species were found in significant number: multiflora rose (457 plots), non-native bush honeysuckles (89), and Japanese honeysuckle (69). The map at right, copied from the study, shows that NNIPs were distributed throughout the state. The dark blue areas represent densely forested areas. The dots represent plots on which NNIPs were found, and the color of the dot represents the class of NNIP.

The study not only counted how many plots had NNIPs on them, but they estimated how much of the plot was covered by each type of NNIP.

Source: Moser, Hansen, & Nelson, The Extent of Selected Non-Native Invasive Plants on Missouri Forestland.

Multiflora rose, which was on the most plots, tended to cover less than 10% of the plots it was on. In some parts of the state, however, honeysuckle covered up to 50% of the area of the plots it was on. (See graph at right, copied from the study.)

The study included only forested plots. Land with other kinds of plant cover were not included.

Sources:

Moser, W. Keith, Hansen, Mark H., and Nelson, Mark D. (2008). The Extent of Selected Non-Native Invasive Plants on Missouri Forestland. In Jacobs, Douglass and Michler Charles (eds.), Proceedings of the 16th Central Hardwoods Forest Conference. http://www.nrs.fs.fed.us/pubs/gtr/gtr-p-24%20papers/54moser-p-24.pdf.