Invasive Plants

Invasive plants have always interested me, and today's exploration of some common exotic and invasive plants with Tom Lee allowed me to reflect on my own experiences with invasive species in New Hampshire.  After graduating UNH in 2008, I spent the summer working at the NH River Council in Concord.  We were trained to look for Didymosphenia geminata, an invasive algae that comes from Siberian Russia.  It originated in a lake, but adapted to the cool mountain streams of New Zealand, where it is believed some fisherman (or one fisherman) transported it with felt-soled waders.  Scientists theorize that the felt made an excellent mode of transport keeping the didymo alive and fresh for its subsequent introduction to America's cool, high altitude Western rivers, northern New Hampshire as well as some streams in Vermont and Canada by those very same fishermen.  Years after this experience, I noticed didymo, or "rock snot" (sometimes it's useful to give invasives nasty names to remind us how undesirable they are) out West in the Snake River located in Grand Teton National Park, and remembered the map of distribution I was shown when training for this job.  I was nostalgic in making the connection, but it was troublesome to see how well established rock snot had become in the beautiful rivers of America's Western ranges.  Rock snot looks to be slimy and smooth and is named for how it appears, but the texture is more accurately compared to that of wet cotton.  When dry, it is very coarse and can live for very long periods of time out of the cold, wet ecosystem in which it normally thrives.  This is one of a few very favorable adaptations that makes it a successful invasive species.

It was very helpful to become familiar with the terms exotic/non-native and invasive.  It is important to understand that not all exotics (exotics and non-natives can be used interchangeably) are "bad" or invasive.  In fact, the number of vascular plants in NH is around 2,500 and around 500 of these are non-native!  At first, this can be a daunting and frankly, depressing number.  But it is important for learners to understand that the number of invasives is far lower and more manageable at around 30.  It's going to be important not to discourage students with big numbers and to encourage solution-based thinking.  For example, you can propose the following to students: "instead of wondering how problems occurred, why don't we focus more on how we can reduce the number of invasives?"

Even pristine ecosystems like College Woods and Barrington Headwaters have invasive species growing in them.  For the most part, these invasives have been kept out or at least kept to the outer edges.  I wonder why this is - have we managed the invasives with Early Detection and Rapid Response?  Or has the ecology self-managed to resist the invasives? 

The social and more specifically, economic impact of invasives is actually quite quantifiable.  With Norway maple, for instance, it is spreading throughout the Northeast and compared to the sugar maple it has inferior sap (yields less sap sugar).  This is a real threat because the maple syrup harvest has long been a staple to the region's economy, and many families rely heavily on its production to supplement their income.  Tourism is also a major source of income in the region, and the autumn leaves are most vibrant on the sugar maple, which also displays many colors compared to the monotone Norway maple.  This tree species threatens our local economy, and I want to be able to teach future generations how to value the native sugar maple citing our economic dependence on it.  I hope that this awareness along with positive solution-based thinking will be a primary stepping stone for empowering society to manage these invasives.

Norway maple leaf (left), and sugar maple leaf (right).  We learned that an easy way to distinguish

 the two is to check the sap; Norway maples have white sap and sugar maples have clear sap

After our informative morning stroll in College Woods, we returned to the classroom for a facilitation from Kim that helped bring some of Tom Wessels' ideas to life.  The "Before & After" disturbance drawings were a really great idea, and I feel like they actually belonged in Wessels' chapter about Junipers and Weird Apples.  Fun activity, and as a visual learner this really helped me conceptualize the impact humans have on their ecosystem highlighting the effect we have on these types of plants.