An ecosystem is influenced not only by plants, animals, and other living organisms, but also by nonliving factors such as soil and water chemistry. In order to protect the natural integrity of the park and to provide more information about the surrounding area monitoring is done of the water, plant, and animal resources. Water monitoring is completed once a month to check for pollution problems, while plant resources are monitored in an effort to control the spread of invasive species. Animals are inventoried periodically to determine which species inhabit the park. The park also monitors species that are considered to be pests, like mice, moths, and wasps, in an effort to prevent damage to historical artifacts and to protect humans and the environment. Human caused factors such as pollution and the introduction of nonnative species, along with weather, climate change, and geologic activity are only a few agents of change that have shaped the park.