Grand Teton National Park and the surrounding region host over 1,000 species of vascular plants. With an altitude variance of over , the park has a number of different ecological zones including alpine tundra, the Rocky Mountains subalpine zone where spruce-fir forests are dominant, and the valley floor, where a mixed conifer and deciduous forest zone occupies regions with better soils intermixed with sagebrush plains atop alluvial deposits. Additionally, wetlands near some lakes and in the valley floor adjacent to rivers and streams cover large expanses, especially along the Snake River near Oxbow Bend near Moran and Willow Flats near the Jackson Lake Lodge. Altitude, available soils, wildfire incidence, avalanches and human activities have a direct impact on the types of plant species in an immediate area. Where these various niches overlap is known as an ecotone.