Invasives

Phragmites - Nature’s styrofoam

A quick look at the problem we here in the northeast experience - Invasive species. To be perfectly honest, it is not a problem that only those of us in this part of the country are dealing with. It is in fact a national environmental challenge that seems to be of growing concern each and every year. Invasive species are organisms that are introduced into new environments where they do not naturally occur, often causing harm to local ecosystems, economies, and human health. These species can be animals, plants, fungi, or microorganisms that disrupt the balance of their new habitats by outcompeting native species for resources, spreading diseases, and altering physical environments.

Invasive species are typically successful due to a lack of natural predators in their new surroundings, allowing them to thrive and multiply rapidly. I chose to center on this topic in today’s blog after driving through one of my favorite sites for photographing the natural world, Iona Island. This is a great setting to take a look at the problem and attempts to deal with it in that over the past few years, changes have been brought about by efforts to remediate the impact of one species in particular, phragmites.

Phragmites is a tall perennial grass that thrives in wetlands and along shorelines. It can grow up to 15 feet in height and has dense stands that can rapidly dominate habitats, affecting local ecosystems. Phragmites’ invasive properties in can outcompete native plant species such as Cattail, altering local biodiversity and disrupting food chains. Beginning in the 1960s and persisting up until about 15 years ago, the marshes of Iona Island were dominated by phragmites rather than the native cattails which originally populated the area.

Cattails

These hardy plants play a crucial role in ecosystems by providing habitat for various wildlife, including birds and insects, while also helping to filter and purify water. Their adaptations to wet environments make them a resilient species, capable of thriving in challenging conditions.

Gone to seed…..

Look closely at this image of a cattail. Each piece of “fluff” is attached to a tiny seed. The fluff acts as a parachute which carries and disperses the seed through the marsh. These seeds are a valuable food source for many resident and migrating birds as well as some small mammals. Botanists estimate that each seed head (such as the one seen here) can hold a remarkable quarter of a million individual seeds! In the spring, many species of birds such as wrens, red-winged blackbirds, vireos, sparrows and even hummingbirds use the fluff to line their nests. Eventually, when the cattail plant dies, it decomposes readily to add to the nutrients of the marsh soils.

Phragmites on the other hand is not a good food source for local wildlife, however. Overall, phragmites provides poorer nutrition that the cattail it replaces. Also, when phragmites dies, it takes “forever” to decay - hence the nickname “Nature’s Styrofoam”. Because of this fact, efforts have been made at Iona to eradicate the phragmites and bring back the native cattails. Efforts have resulted in over 97% of the phragmites being eliminated followed by the reestablishment of many native plants. Several species which had been absent or present in minimal numbers have returned to the marsh since mitigation. Virginia rail, least bittern and marsh wren are now making a comeback. To learn more about the restoration of Iona Island Marsh, click on the green button below.