Spring 2015 NAP Newsletter

Upon entering Oakridge, one might expect to find litter and thick brush lining the busy sidewalks. However as I made my way into this lonesome forest, I knew right away that there was much more than meets the eye. Divided by Huron Parkway, Oakridge Nature Area sits south of Glazier Way encompassing 8 acres of oak-hickory woods and wetland. Within these woods a portion of Miller Creek silently runs along a rare type of Michigan wetland called a fen. A fen is characterized by its water chemistry, namely it is pH neutral and contains a high amount of dissolved minerals relative to other wetland types. Typically dominated by grasses and sedges, the Oakridge fen is no exception to Ann Arbor's beautiful and diverse wetlands.

After just one visit to Oakridge, I was completely sold on its beauty and importance in our community. With an almost "untouched" appeal (there are no marked trails within Oakridge), it is as if I had been far removed from the bustling intersection with only a faint, muffled sound of nearby passing traffic. In my relatively short venture through this area, I found several animal tracks pressed into the dark soils, large vines winding all around making it difficult to find where they begin and end, and a subtle yet calming sound of water making its way along the creek. From this experience alone, I have decided not to be blinded by my everyday commute and errands to the diverse and special places that reside on the sides of roads, even within my own neighborhood.  I encourage you to do the same: take time to seek out natural areas such as Oakridge that are surely waiting to be noticed for their diversity, ecological importance and unmistakable beauty.

But all that pulling really does make a difference! At NAP, we have been keeping track of our fieldwork in the parks since 1994. Looking at past records of the amount of time it took our field crew and volunteers to clear all the garlic mustard out of a given area each year, we find documentation that garlic mustard can be greatly controlled. As the garlic mustard population decreases from year to year, the time it takes to clear the area also decreases. Several of Ann Arbor's parks and natural areas have shrinking garlic mustard populations in their higher-quality sections. The graph below illustrates a good example at Huron Parkway Nature Area. There is a clear downward trend in the amount of time our field crew spent pulling garlic mustard in the park over the years.  In less than a decade, our volunteer and crew's work effort has decreased from 109 hours in 2007 to 29 hours in 2014!

As one can see, the downward trend isn't a smooth one – some years required a little more effort than the year before. There are many factors that may cause this sort of fluctuation from year to year. If we have an early spring, for example, the garlic mustard may get an early start and cover more area than it would have otherwise. Or there may be a significant number of seeds lying dormant in the soil, just waiting for the right conditions to sprout (sometimes as much as 10 years after they were produced). And because garlic mustard is biennial, it is not uncommon to see its population rise and fall as plants that were tiny sprouts during the first year of their life bolt and flower the next year.

It's important not to give up if you see these temporary increases after years of effort. Our data shows that if you stay determined and keep chipping away little by little, you will be able to see a difference over time. If you're feeling discouraged, it can be helpful to talk to other folks who have had success in controlling garlic mustard. They may have suggestions for different methods you can try. More importantly, they can be a good source of moral support in what could seem like an uphill fight. And we at NAP are also here to say that you can do it! Keep pulling away, and eventually that patch of invasives will be a distant memory.

For more identification tips, watch this video from the Invasive Species Council of Metro Vancouver http://tinyurl.com/HogweedVsParsnip. Please note, both Cow Parsnip and Giant Hogweed can cause burns, so it's best to avoid touching either of these giant Apiaceae.