Snow blankets much of Michigan now, which may have you dreaming of summer vacations to the beach, and for good reason – Michigan has plenty to choose from! But sandy shores and their hilly companions—dunes—support more than just a retreat from the daily grind.
Dunes in Michigan are unique because, unlike their desert counterparts, they are impacted greatly by the water of the Great Lakes. Fluctuating lake levels contribute to dune formation by stabilizing the dunes with increased water levels as well as increased wave action in high years. These impacts are usually so slow-moving that they go unnoticed, but recent erosion along Lake Michigan due to increased lake levels had the dramatic effect of damaging some houses built close to the edges of these dunes.
One distinguishing characteristic of Michigan’s dunes is the amount of vegetation that can be found on them. There is a limited supply of sand in the Great Lakes being deposited on the dunes. This in time allows for various grasses and trees to take root and grow, further slowing or stopping the movement of the sand and allowing for more vegetation to grow. These plants are therefore critical to preventing erosion and dune migration.
Several rare plant types are supported by these dune habitats including Pitcher’s thistle, Houghton’s goldenrod, and Lake Huron tansy, just to name a few. At MNA’s Lake Huron Sand Dunes Plant Preserve in Chippewa County, a unique natural community known as a “wooded dune and swale complex” exists as a series of sandy ridges and low, swampy areas that were formed in multiple stages as lake levels receded around 12,000 years ago.
As with many natural communities throughout Michigan, a major threat to the health of this sanctuary is the impact of invasive species. Particularly at Lake Huron Sand Dunes Plant Preserve, invaders such as Spotted knapweed and European Marsh thistle are aided by habitat disturbance. MNA monitors the sanctuary regularly for signs of disturbance and works to remove invasive species before they become too widespread.
So as you plan your next Michigan beach vacation, remember that the sand is part of a much larger and ever-changing habitat complex.