Alexandra Bramsen
ENVS 20
Professor Bolger
October 8, 2020
Neighborhood Biodiversity – Hanover, NH
On the main Dartmouth campus, because the majority of plants are controlled the other types of species that appear seem responsive to that control. The dotting of large oaks and pines allow for small birds to rest in their branches. Flowering bushes and other cultivated low ground plants seem to attract insects like a few butterflies I spotted (one was all yellow), the Common Eastern Bumble Bee, and the Melanoplus grasshopper. These trees can be homes for other small creatures like the chipmunks and squirrels I saw often while on campus, that also use the bushes to hide in. Another factor in what types of species I observed on campus, were those that did not mind human interaction and fragmentation; insects, moths, butterflies, spiders, and even the chipmunks and squirrels appear to be used to a habitat with extensive human interaction. These tend to be smaller species, and I wonder if that is because they are less noticeable to the casual by passer than other species, so have less direct intrusion. Another example of how species size might matter on the campus, could be for instance, when the species crosses a road, being smaller size would mean they were less likely to be hit by car.
Most of my observations were centered around Occom Pond. Here, while there were still many tall trees like oaks and pines, there were also more wild ferns, flowering plants, fungi and other shrubbery. My assumptions with these observations were that the combination of a large water source, significant sunlight from a low-density canopy, low control or human disturbance, but the possibility of colonization from surrounding gardens is what shaped this highly diverse space. In turn, this diversity and rich patch of resources could also be how other species diversity was noticeable. While in this space larger animal species were noticeable, such as the white-tailed deer, a few ducks, other birds, as well as the usual insects, chipmunks, and squirrels. While Occom still has significant human intrusion and disturbance, the food and water, mixed with lower human control, allows for that biodiversity to appear to significantly increase. In other words, it allows for a wider range and number of niches because of its larger resource spectrum. This larger resource spectrum is achievable because of its relatively higher isolation as a habitat patch compared to spaces more on campus. As mentioned before, the fact that it is not completely isolated and is in fact surrounded by plots with large gardens may also contribute to higher diversity as there may be a higher rate of introduced species. Although it was apparent that particular flowering plant species, like the American asters, were favored in this habitat.
While I did make observations in Pine Park, just near Occom, I did not find as much diversity. This space is also often used by people for walks, jogs, and other recreation, but it probably has the least drastic disturbance by society, although there has been logging and clearing of paths. This has meant that the majority of its species are late-successional species, so contains a much denser tree canopy than Occom and fewer low-lying plants. I also found it difficult to find other animal species in this place because of its larger size, they must generally be more dispersed. The ground currently is mostly covered in decaying leaves, so the appearance of low diversity may be deceiving. The leaves are probably ideal for decomposers, insects, and other forest species that are less obvious. I assume that my observations in the park could not be conclusive because of its large size, different range of species that may be less visible, and the fact that I spent less time observing it than Occom pond and campus simply due to distance.