The grassland condition index raster data layer assigns to each 30 meter pixel in the GCPO a condition index score generated by the presence or absence of a set of desired conditions such as patch size, vegetation height, etc. This grassland bar code layer indicates which conditions contributed to the index value score, and by how much, by use of a nine-digit code. The digits in the code represent the following input conditions in order: potential for restoration, presence of a grassland ecological system, presence of prairie (a subset of grasslands characterized by the presence or dominance of native vegetation), configuration in a patch > 100 acres, and the four site-level condition endpoints: vegetation height > one meter, vegetation cover > 80% herbaceous, at least one recorded disturbance event, and tree density < 10/acre. In other words, if the nine-digit code were represented by letters ABCDEFGHI, the input layers would be described as follows: A = potential prairie restoration pixel: a prairie or grassland ecological system is indicated by LANDFIRE’s Biophysical settings layer, and National Land Cover Database (NLCD) 2012 indicates that this pixel is neither developed nor open water. A value of 1 here indicates that these conditions are met, a value of 0 indicates they are not. B = A grassland pixel, derived from LANDFIRE existing vegetation type data layer and various state-level assessments and observations collected by the GCPO LCC for the rapid ecological assessment of grasslands. A value of 2 in this position indicates that the condition is met, 0 indicates that it is not. CD = a two-digit score, either 00 or 10, representing 10 points added to the index value for those pixels where the presence of prairie (dominated by native grasses and forbs, as opposed to general grasslands in a variety of conditions) is indicated. E = a value of 5 added to each pixel that is within a grassland patch greater than 100 acres in size. Pixels that don’t meet this condition have a value of 0. Positions FGHI indicate values of 0 or 1 indicating the absence or presence of the four site-level condition endpoints in the order described above. The condition index value can be obtained from the barcode by summing all the numbers represented, with the understanding that the 1 in the third (C) position stands for 10.
