Zack and Marina's Journey Through the Indiana Dunes
Hey There :)
We're Zack and Marina, and a few weeks ago we went on a trip to the beautiful Indiana Dunes. While walking along the picturesque path, we started talking about human impact on the environment. We agreed to pursue a method of preservation for this amazing ecosystem.
Within the last dacade, there has been an increased focus on environmental issues, highlighting a deeper concern and a willingness to help. That's amazing, but a person cannot help improve the conditions of an environment if he or she doesn't have a basic understanding of the area and the idea of enviornmental succesion.
The Basics There are some terms and processes that we will discuss throughout, which are very specific to the field of study. (We had no idea what they were before this began either.) • Percolation • Succession • Various plants and critters that inhabit each level Most importantly, however, we will be exploring ways to maintain the environment and keep it from deteriorating.
Percolation Percolation is a measure of how much water an area of ground can hold. This is used to identify differing levels of ground composition, mainly soil amounts. The longer it takes water to absorb into the ground is an indication of a larger amount of water-holding soil. This indicates areas that are able to support vegetation. Percolation has a very important role when it comes to ecological concerns, because the higher the percolation time, the more nutrients are retained in the soil, affecting its fertility.
Succession Throughout the past couple of thousand years, the water level of Lake Michigan has lowered gradually, leaving different stages of species at each level. Its staggering to think that the Wooded Dunes were once a sandy Beach, and that the Jackpines are the outcome of adaptation due to the presence of glaciers. The way Zack and I saw it, there were bits and pieces of history that could be gathered from this land. The dunes are characterized by the following levels of succession...
Beach As drift washes onto the shore, decomposers are able to break it down into humus. The humus provides nutrients for the later stages of succession. Dead animals also contribute to this process. The lack of soil makes the percolation rate very high, at an 18 second average. Also, there is very high levels of both sun and wind exposure. Animals like digger wasps and other burrowing insects live under the drift, mixing nutrients into the sand.
Dune Builders Here we encounter the beginnings of vegetation, the pioneer plants. Enough humus has been assembled so plants like Marram grass and sand reed can start to grow and bind the sand together. Combined with high wind exposure, dunes begin to build up behind the bound sand between the roots. Slight amounts of soil hold small amounts of water, very close to percolation times on beach, with an average of 20 seconds. This and lots of sun leads to good growth of pioneer plants in the nutrient lacking soil.
Lee Side Lee side is the protected side of the dune. In other words, it is the side of the hill (dune) that faces away from the beach. This means that there is less wind exposure so more soil and plant roots form, supporting the dune. Less durable plants like little bluestem are prevalent here. Percolating here took an average of 52.4 seconds.
When the dunes grow and nutrients and soil builds up, so the area can sustain larger jackpine and juniper trees. These trees bind even more soil together, still increasing the size of the dunes. The trees grow taller, preventing ground sun exposure and leading to a decline of the smaller pioneer plants and grasses. Instead, leaves and other organic material line the ground. With the help of decomposers, the amount of humus increases and becomes more nutrient rich. Trees block lots of the wind the area would receive Percolating in the Jackpine area took an average of 377 seconds due to an increasing soil buildup.
Wooded Dunes Here one can find various types of trees. This diversity is indicative of a higher level of succession. Higher soil content leads to massive tree growth, prohibiting sun exposure for the ground limiting ground plant growth. This also influences percolation, with an average of 261 seconds.
Some features that are common at the dunes include:
Interdunal Pond Interdunal ponds form in depressions either between dunes, or caused by blowouts. They gather water, or sit below the water table, causing small shallow ponds to form. There is low wind exposure, and high sun exposure.
Blowouts Natural blowouts are caused by heavy winds, erosion, and storms. Because the area is disturbed, lower levels of sand and soil are distributed at the site but still present. High sun exposure contributes to the return of the dune builders, and the succession process begins again. This is known as secondary succession, as opposed to the original primary succession where no soil was present. They can also be caused by humans and animals, as they repeatedly disturb the vegetation. Blowouts leave an area in various stages of succession, therefore disturbing it. The Percolating average is 23 seconds at the blowouts
Sandmine Succession This is a mixed area of sand, dirt, pioneer plants, and trees. Humans excavated the ground for selfish gains, disturbing what would have been part of the wooded dune. Sun and wind exposure is high, much higher than it should be in the area. The mix of large trees and bare sand leads to various levels of sunlight and wind exposure. Some areas retain higher levels of soil, but some donâ€™t and percolation times vary.
The Bottom Line Lets face it, we are not always kind to nature, and often we make selfish decisions, like littering and creating unnatural blowouts because of our paths. It would take a lot to stop Global Warming, but we can all do our part by being responsible! Not throwing our trash all over the dunes and walking on designated paths is a great start. You hear it all the time, but it is true: preserving the environment means that our children, and their children, and their children (you get the point right?!) get to enjoy it as well.
Zack C. Marina S.