Identifying & Mapping Disturbed Features

Features with Disturbed USE have anthropogenic disturbance without clear or consistent management within the feature, or are influenced by activity in adjoining features, or are disturbed by being fragmented into vegetation features < 30 m in dimension.

Diagnostic characteristics of Disturbed features:

  1. Areas within 15 m of high-disturbance USE areas (Constructed, Livestock, Horticulture, Mine & Fill) that are not clearly part of clear USE features outside of this area.
  2. Small patches of Regrowth vegetation < 30 m in dimension and < 1000 m2 in area without clear plans for harvest (Not USE = Forestry) or significant structures or debris. Some Disturbed features may be >1000 m2, but these must be complex, reticulated features with many narrow protrusions or are highly disturbed with structures and debris.
  3. Features with no clear USE with small (< 5 m) or abandoned structures or debris covering ≥ 10% of the feature, OR containing a single structure or patch of debris that is > 3 m in dimension (> 10 m2).  Structures may include earthen structures such as pits and earth walls, and debris may contain either anthropogenic materials or dumping of natural materials (soil, rocks, etc.) transported from other locations.
  4. Areas with COVER = bare soil caused by disturbance, not associated with any other USE.

Methods for identifying & mapping Disturbed features:

  1. Identify linear Disturbed features, such as field borders and unmanaged regrowth hedgerows.
  2. Use a buffer to define a potential Disturbed zone for identifying the influence of disturbance from adjoining high-disturbance USE features.
    1. Select all polygons with USE = Constructed, Livestock, Horticulture, Mine & Fill.
    2. Externally buffer these polygons to 15 m using GIS.
    3. Overlay the potential Disturbed zone layer on other polygons across the sample cell.
    4. Identify features without clear USE that have >50% of their area within the potential Disturbed Zone.  These features should be considered Disturbed, unless they have another clear USE
  3.  IF vegetation features without clear or consistent USE remain as < 30m “holes” (< 1000 m2) within areas of non-disturbance-causing USEs, such as agriculture, these features should be mapped as Disturbed features, as they are considered fragments that are disturbed by having a small size (high edge/area ratio). 
  4. AFTER mapping larger  Forestry and Fallow features:
    1. IF there is clear evidence of structures, debris or other significant anthropogenic disturbance that are far greater than typical for Forestry, Ornamental, or another managed USE, a larger feature should be mapped as a Disturbed feature.
    2. IF features with clear edges but without clear USE are easily recognizable within larger areas of Forestry or Fallow, and show clear evidence of disturbance so that they should not be considered Forestry or Fallow, map a Disturbed feature within these larger features.
    3.  IF there are significant areas of a larger Fallow or Forestry feature that is within the potential Disturbed zone, use specific mapping rules to determine whether to map separate Disturbed features in this zone.
  5. Prior to classification of Disturbed features by groundtruthing, they should be cut into smaller features to facilitate consistent classification.  Follow the specific mapping rule for Cutting Large Disturbed & Ornamental Features Prior to Groundtruthing