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Plant species composition data for Saddle grid plots from 1989 to ongoing, yearly from 2010

Data set creator(s): Hope Humphries; Marilyn Walker

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For methodology questions, contact Hope Humphries
INSTAAR, University of Colorado
1560 30th St., UCB 450
Boulder, CO 80309-0450
(303) 492-2594

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Permanent 1-m^2 plots were established beside each of the 88 Saddle grid stakes in 1989 by Marilyn Walker, who led the sampling effort until 1997. Each plot was located within 2 m of the stake, but always in the same vegetation type as that associated with the stake. The distance and direction from the grid stake were randomly selected, and thus varied from plot to plot. Point quadrat measurements have been made at irregular intervals from 1989 to the present (1989, 1990, 1995, 1997, 2006, 2008,  and yearly from 2010 onward). The point-quadrat technique used was identical to that described by Auerbach (1992) for sampling in 1989 to 1997: The point-quadrat method was used for estimating plant cover. The aluminum point-quadrat frame was 1 m^2 in size, with double-layer filament spaced 10 cm apart to make a 10 x 10 cm grid, for a total of 100 sample points per plot. Before sampling, the point-quadrat frame was leveled and plots were permanently marked in the following manner. Aluminum tags were nailed into the ground so that a frame could be repositioned in the same location from year to year; i.e., tags with a hole in the middle were used to define the locations for the point frame legs and four tags with a "X" stamped on them (positioned somewhere inside each of the frame corners) were used to define alignment of the frame by positioning the string crossings over these "X"s. Plant genus and species were recorded for top and bottom hits at each point for 1990-1997 data. In 1989, middle hits were also recorded. A plant species hit occurs when a plant part touches a thin metal stick placed at the intersection of 2 filaments in the quadrat. If plant parts of a given species touch the stick at multiple places, only one hit is recorded. In the next sampling year, 2006, and continuing to the present, all hits were recorded at each point, but frame distances were not measured.  In addition, exact repositioning of the frame was not possible in some plots due to absence or relocation of tags. Data are formatted as one species hit per row (“string of pearls’).


Study sites were the 88 Niwot Ridge Saddle grid points. Original plot sheets, data entry spreadsheets, data collection/entry notes, and additional point-quadrat technique descriptions are stored with the NWT LTER data manager.

Date Range:

1989 to ongoing


yearly from 2010


year, plot number, point identification number, hit type, species code, species name

Location: Saddle grid plots

At a glance:

Saddle site
Elevation: 3500 m


Location Group: Saddle

Found within: Niwot Ridge (USFS - UNESCO Biosphere Reserve)
Located in: USFS - UNESCO Biosphere Reserve
(Click to learn more about these locations)

More data from: Saddle

Core Data Set: yes Core Area: Populations
Discipline: Plant/vegetation ecology
Award Or Grant: DEB1027341, DEB1637686

Data Citation

Humphries, Hope. Walker, Marilyn. 2019. Plant species composition data for Saddle grid plots from 1989 to ongoing, yearly from 2010.

CU Boulder

This material is based upon work supported by the National Science Foundation under Cooperative Agreement #DEB-1637686. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necesarily reflect the views of the National Science Foundation.

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