The ability of pollen from small lakes and ponds to sense fine-scale vegetation patterns in the Central Rocky Mountains, USA

Pollen ratios and linear discriminant analysis were used to detect fine-scale vegetation patterns in the subalpine zone of the central Rocky Mountains, USA. The vegetation of this zone is a mosaic of conifer forests and treeless parks dominated by sagebrush (Artemisia spp.) and grasses. Previous work with pollen surface samples in the region has correlated modern pollen rain to broad-scale vegetation zones (e.g. steppe, montane forest, subalpine forest, and tundra), but little effort has been made to detect fine-scale (hundreds to thousands of meters) patterns within these vegetation zones. Previous theoretical studies suggest that vegetation patterns on the scale of hundreds of meters should be recorded in the pollen deposited in small ponds. Pollen surface samples were collected from small ponds and lakes (30-350 m diameter) from subalpine vegetation in Colorado and Wyoming. An additional set of samples was collected from small ponds in a park and the surrounding forest in the Wind River Range of northwest Wyoming. Pollen percentages were not dramatically different in park and forest assemblages, but the ratio of conifer to herb and Artemisia pollen (C:H) and the linear discriminant score were successful in separating park and forest pollen assemblages.