In Chattanooga, there are several places to go and enjoy the outdoors. With so many forests and mountains, you can expect a wide range of biodiversity. Our class took a trip to one of the more well known areas, Stringer’s Ridge. It is a very popular hiking area due to the sheer amount of diversity present, giving hikers a beautiful scenic route.
With the area being such a popular hiking spot, there was a high level disturbance present. The soil on the path had been packed down and nothing grows on it. It is also very shadowy. All of the trees in the area are extremely tall and have several leaves on their limbs. Given that not much light can shine through, the ground was incredibly bare. Only a few sprouts were present beneath the trees, with no bushes or grass anywhere. It was also incredibly muddy because the water could not evaporate fast enough under the tree cover.
For our observations, we were given a 165 ft long measure and a piece of string. We extended the measure to the whole 165 feet. At every 5 feet, we laid the string out off to one side of the path and counted how many different species the string touched. To determine which side of the measure we looked at for diversity, a coin was flipped. This helped to eliminate any bias and make sure that our sampling was randomized. If this had not been done, our results could have been skewed. Below is a scatter plot which shows the amount of different species we found at each 5 ft mark.
We can see that as we moved from the path towards the interior of the forested area, the amount of species we encountered increased. Also, as we moved farther along the trail and along our measure, the diversity grew. we came across the most species towards the middle of the path. This is probably due to the fact that those samples were taken from an area that did not have another path on the other side of it. Most of the other sample sites were enclosed by a path on either side of it, but in the middle of our measuring there was a site with no path running along the other side.
A regression test is used to determine the correlation between the dependent and independent variables of the experiment. With most experiments, a dependent variable will change due to the independent variable. The independent variable for our study is the 165 ft measure, and the dependent variable is the number of species found along the measure. The only number we are concerned with after running the regression test is the P-value. This value shows whether or not there is any correlation between the two variables. Our test yielded a P-value of .0000449, which is lower than our standard .05 value. Because this value is lower than .05, it means there is a significant change in our dependent variable because of a change in the independent variable.
We can see all of this diversity because the area is hardly affected by humans. Of course, the paths have been used so much that nothing grows on them, but for the most part, the area remains intact. The same cannot be said for more urbanized areas. Fragmentation has become a serious issue that severely affects biodiversity. It occurs when the natural area becomes cut off from one another into different sections. This can be due to roads, railways, houses, and so on. The more the land gets divided up and the more trees and plants that are removed, the less diverse a place becomes and the less there are interactions between and among species. Habitat fragmentation reduces the size and increases the spatial isolation of plant populations (Young, et al, 1996).
This is true for several ecosystems, but especially for river floodplains. They are home to a wide array of species and a rich soil composition. Besides being important for the diversity of life, these areas are also needed to maintain water quality and prevent erosion. A study of Japanese river floodplains done by the University of Tsukuba found that the younger maple trees had less genetic variation than the older ones. This goes to show that the more forests that are cut down, the less likely they are going to be genetically different. Genetics play a huge role in survival and can make or break a species if a parasite, disease, or environmental change occurs. If the variation is low, the species can be wiped out and may not recover.
Bringing awareness to these issues is the only way to ensure that an environment can bounce back from any catastrophic event that may occur. There are efforts going into the river floodplains to help the genetic diversity increase. The study done in Japan recommends preserving forests along rivers as well as the forests surrounding them to promote diversity and increase the connectivity of the rivers. This way the genes can flow freely from one area to another with pollinators, seeds, and other forms of natural transportation.
Young, A., Boyle, T., & Brown, T. (1996, October). The population genetic consequences of habitat fragmentation for plants. Retrieved from https://www.sciencedirect.com/science/article/pii/0169534796100458
Saeki, I., Hirao, A. S., Kenta, T., Nagamitsu, T., & Hiura, T. (2018, February 28). Landscape genetics of a threatened maple, Acer miyabei: Implications for restoring riparian forest connectivity. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0006320717312636?via=ihub
Happy Earth, Happy People 