Improving Prairie Pond Counts with Aerial Video
and Global Positioning Systems
Results: Relationships of Pond Counts on Transect Segments
The number of ponds detected on the video was positively correlated (r = 0.87, t = 9.58, P < 0.001) with the number of ponds from aerial BGS of the 30 transect segments (Fig. 4). The slope of the regression of ocular aerial counts on video counts was not different from 1 (t = 1.96, P = 0.060), and the intercept was not different from 0 (t = 0.049, P = 0.961). This indicated no consistent tendency for aerial BGS to over- or underestimate the number of ponds compared with the pond count from video interpretation. However, examination of the scatter plot and standardized residuals showed that the video pond count was larger than the aerial BGS pond count for some transect segments. A decrease in the number of ponds between the time of the video survey and aerial BGS, commission errors, boundary errors, subjectivity of trying to exclude Type I wetlands from the video pond count, and interpreter experience probably contributed to the larger video pond counts compared with the aerial BGS pond counts for these transect segments.
Figure 4. Number of ponds from aerial survey of the Aerial Waterfowl Breeding Ground Population and Habitat Surveys regressed on the number of ponds from video interpretation of 30 0.2- x 29-km transect segments in southern Saskatchewan, May 1992. Dashed line is for a relationship with a slope=1 and an intercept=0.
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