The human presence of the University of Michigan Biological Station and the growth of Acer saccharum.

Abstract

With humans building new cities, roads, and public transportation projects, we are disturbing habitats around the world. To study the effect human actions have on these habitats, we used the University of Michigan Biological Station (UMBS) as a model. Although UMBS was established to study biological and ecological processes uninhibited in nature, there is a very real possibility that our actions from building and living at UMBS have left a tangible mark on the surrounding environment. To test whether our presence here has a significant effect, we chose Acer saccharum, or Sugar Maple, as our model plant species. We identified several perturbations linked to human actions such as vegetation removal, transportation, building developments and agricultural uses. These variables were measurable by testing for soil density, soil moisture, soil nutrient levels (nitrate, phosphate, ammonium), light intensity, and total neighboring tree biomass. We found that there was a significant difference in average annual tree growth between two test sites: on and off-campus. The trees off-campus had a higher average annual growth rate than the trees on-campus. All of the variables excluding phosphate levels were significantly different between both test sites. The results we obtained can be explained partly by differing levels of soil density which could have reduced soil moisture and thus affect tree growth. The difference in nutrient levels could be due to the human action of clearing out trees at UMBS to build cabins, research laboratories, and other buildings as well as the constant removal of leaf litter on-campus grounds. Our findings can be applied to help UMBS in future landscape architecture decisions, or even be applied to larger cities to ensure that they are doing as much as possible to minimize adverse disturbances to flora, fauna, and ecological processes related to human actions.