Plant species composition data for Saddle Nodal Plots, 1971-ongoing.

• Main Author: Ebert-May, Diane
• Format: Dataset
• Language: English
• Published: Environmental Data Initiative 2018
• Subjects: Tundra
• Online Access: https://dx.doi.org/10.6073/pasta/973821e62fd6d33481f31fc0201fbd5c; https://portal.edirepository.org/nis/mapbrowse?packageid=knb-lter-nwt.501.1

To study long-term changes in alpine tundra vascular plant communities, thirty permanently marked plots were surveyed in 1971. These same plots were surveyed at twenty, thirty, and forty year intervals from the initial sampling date; in 1991, 2001, and 2011. Plots are one by ten meters, divided into ten subplot quadrats, and marked with rebar. The presence or absence of each vascular plant species was recorded per plot (species_composition_vascular_pres_abs.dem.data.csv). The cover was recorded for each species that appeared in a one meter by ten centimeter strip at the base of each quadrat within each plot; it was assumed that this strip was representative of the cover within the entire quadrat; percent cover was then averaged for each plot (species_composition_vascular_cover.dem.data.csv). The cover of non-vascular plants, soil, rocks, and lichens was also recorded within the strip (other_cover.dem.data.csv). These data have been used to study the changes in vascular plant communities and cover across habitats following a moisture gradient on the saddle portion of Niwot Ridge; these habitats include dry fellfield, dry meadow, moist meadow, wet meadow, snow bank, and shrub tundra. While we have observed some changes in species richness and cover in the plots, overall the plant communities seem fairly stable over time.