An analysis of plant community change 1811: Present in western New York using historical surveys

Background/Question/Methods Analysis of the vegetation data in settlement-era property surveys can aid our understanding of historical landscape change. By demonstrating how past vegetation differs from current patterns, historical studies can identify the effects of land use, the results of long-term ecological processes, and the degree of change in forest composition and wetland distribution. Working with historical data presents unique challenges due to the incomplete preservation of historical records, the fact that data were originally collected for non-scientific purposes, and the variety of data collection methods within one dataset. After locating land surveys from 1811 for the 100,000-acre Connecticut Tract in western New York, ecological data from the surveys were transcribed and then analyzed using ArcGIS software. The Connecticut Tract is ecologically significant because even today it contains hardwood forests and wetlands that shelter rare and endangered species. The surveys contained both witness tree data and line descriptions, which we analyzed for species composition and community type. We evaluated the two data types separately both to identify and to minimize the bias that might be present in historical data. We used the community type results together with surveyor notes to extrapolate wetland coverage, which we compared with 2006 National Wetlands Inventory Database.

Results/Conclusions Witness tree results indicate that American beech (Fagus grandifolia) was by far the most common species in the area, with a relative density of 65%. This result correlates well with current species composition in the area, which is still dominated by beech. The line descriptions also correlate well with current community distributions, with beech-maple-basswood covering much of the study area both then and today. Comparisons to the National Wetlands Inventory Database revealed that many of the wetlands that were present in 1811 still exist today, particularly in the Byron-Bergen Swamp and in the wetlands along the Lake Ontario shoreline. However, the survey results indicate that many wetlands between Ridge Road and the Erie Canal have been lost, possibly during the construction of the canal in the 1820s. This study fills in missing historical data between the two largest land purchases in western New York. We found that an analysis of both bearing tree and line description data helps to overcome gaps due to incomplete records.