This past summer I spent hours in Black Rock Forest (Cornwall, NY) doing research for my senior thesis. My daily routine required that I trudge through dense thickets of thorny Japanese barberry (Berberis thunbergii) on a daily basis to study its effects on the understory ecosystem in the Hudson Highlands forest.  Japanese barberry is an invader that does three main things to the ecosystem that it invades: 

1. It changes soil pH which allows it to out-compete other native species for space and resources and allows it to spread further (Li et. al 2008)
2. It facilitates the invasion of other non-native species (i.e. Japanese stilt grass, garlic mustard, earthworms; Ehrenfeld et. al 2001)
3. It is disrupting the habitat of many native species (i.e. salamanders, snakes, bears, etc.) by replacing native understory vegetation and seedlings (Maerz et. al 2009)

After a long, but fruitful summer of research, I was ready to return home to California to see my family and pets.  When I arrived home, after saying the usual "hellos" to everyone in the house-hold I decided to take a walk through the garden. I was strolling along lightly, glad to be home, when something stopped me dead in my tracks---there in a remote corner of my back yard was the plant that I had been fighting with all summer! I ran back into the house, incredulous that this would have happened. "Mom, when did you get that thorny shrub in the back right corner of the yard?"

"Oh, you mean the one with the red berries? I got it about a month ago, isn't it lovely?"

"Mom that's the plant!"

"What plant?"

"The invasive one that I've been studying and talking to you about all summer long---the one that takes over and transforms forest ecosystems."

"Oh, I'm sorry, I didn't realize that was the same plant. It sounded so appealing on the nursery card. It said that it would attract birds with its berries and be deer resistant."

"Yes, those things are true, but that's what helps it spread. It gets into native forests by birds eating the seeds and dropping them in the woods and then it eventually takes over."

"Oh, I just didn't realize it. You can pull it out of the yard tomorrow."

And then it hit me, although I had been talking about it all summer long, telling her everything I knew about what this plant was capable of, I had still not been able to get the message across.  My mother is an extremely intelligent woman, but I had still failed to communicate the importance of the issue at hand.  However, I was not the only one at fault here.  The nursery selling the plants, the state government for allowing the plants to be sold, the home and garden magazine that recommended the plant because it attracted birds---all of these were at fault here.  Something must be done to bridge the gap between the scientists studying the organisms that are invading and transforming native ecosystems and the people who are planting them in their gardens as ornamentals.  People need to know that the seemingly harmless deer resistant, bird attracting shrub they are planting in their yards is being spread to forests and disrupting the native ecosystems there.

If anyone knows of any organizations or nurseries that are fighting to stop the spread of invasive plants, please leave a comment for me.  My goal is to start talking to people who are making an effort to solve this problem and give them the tools to talk to each other.  If anyone would like further reading on this issue please consult the three papers below:

Ehrenfeld, Joan G., Peter Kourtev, and Weize Huang. "Changes in soil functions following invasions of exotic understory plants in deciduous forests." Ecological Applications 11 (2001): 1287-300.

Li, Jinbao, Chengyuan Xu, Kevin L. Griffin, and William S. F. Schuster. "Dendrochronological potential of Japanese barberry (Berberis thunbergii): A case study in Black Rock Forest, New York." Tree-Ring Research 64 (2008): 115-24.

Maerz, John C., Victoria A. Nuzzo, and Bernd Blossey. "Declines in woodland salamander abundance Associated with non-native earthworm and plant invasions." Conservation Biology 23 (2009): 975-81.