Page 15 - Interp Book

Methods

Collection of Field Data

OU and partner personnel collected ground data on landcover, composition, and
ecological system using a legend initially developed via expert committee. The starting
point for the legend was NatureServe’s Ecological Systems classification, but this was
supplemented with an eye toward mapping all landcover types within each Ecological
System (Ecological Mapping Subsystem) if those cover types existed. In addition,
agricultural and other human-related types were included in the legend. The general
data collection procedure included:

1. Sample plots were located either near a road or on accessible private or public
lands. Locations were precise, based on use of a GPS and GIS software on a
computer in the field vehicle. Samples sites were selected based on road or
property access and variation in image signature or mapped soil types (i.e.; high
diversity in landcover and mapped soils types was desirable).
2. Samples along roads were collected at approximately one-mile intervals, often on
both sides of the same road, starting from a random location. In addition,
samples were collected at many stream/road crossings, and where uncommon
plant communities were noted.
3. For data collected along roads, we were limited to views from the right-of-way, air
photography, and other environmental data layers loaded on the laptop, including
county SSURGO soils. Where trees obscured the view away from the road, we
relied primarily on aerial photos and road-side observation to select a sample plot
of relatively homogeneous vegetation. All sample plots were located at least 60
meters from the road within the center of a square with sides of at least 50
meters, to help ensure that the footprint of a corresponding 30 m satellite pixel
fell within a homogeneous land cover patch.

We collected a standardized suite of data using a computerized feature data form with
drop-down windows to reduce mistakes, and we took a picture at most site locations
(Table 1). Drop-down lists used plant names from the USDA Plants database. Initial
species lists for Phase 1 were developed by referring to information already prepared
for areas in Texas adjacent to Oklahoma.

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