Impact from Tourism on Vegetation Greenness in Yellowstone National Park

Abstract: Tourism has increased drastically during the last decades in Yellowstone National Park, from nearly 20 000 visitors in 1910 to almost five million visitors in 2021. Yellowstone is an important ecosystem with unique wildlife, and geological and cultural history. It has a high variety of plants and serves as the home for many different animal species. Previously, tourism has been found to have an impact on vegetation. Trampling reduces vegetation and tourists scare away animals and pollute the waters. The aim of this thesis is to study the effects of tourism on vegetation greenness with the use of remote sensing and the normalised difference vegetation index (NDVI; a proxy for vegetation greenness) in Yellowstone National Park, USA. To study the impact of tourism, the area in the park was divided into different zones depending on their distance to roads and trails being the source of influence from tourism. The NDVI values are being compared between years from 1991-2013, with a lower tourist rate, and the years 2015-2022 with a higher tourist rate. Vegetation close to roads seem to be more impacted by the increased amount of tourism than areas close to trails. However, the results cannot prove that there is any statistically significant impact from tourism on any areas.