Vegetation classification and mapping at Roosevelt-Vanderbilt National Historic Site

Sechler, Frederick; Edinger, Gregory; Howard, Timothy; Schmid, John; Eastman, Elizabeth; Largay, Ery; Sneddon, Lesley; Lea, Chris; Von Loh, Jim

Vegetation sampling, classification, and mapping to plant associations and land use types were conducted at ROVA, which includes the Home of Franklin D. Roosevelt National Historic Site (hereafter known as “Home of Franklin D. Roosevelt NHS” and contains Roosevelt Farm and Forest), Vanderbilt Mansion National Historic Site (hereafter known as "Vanderbilt Mansion NHS"), and Eleanor Roosevelt National Historic Site (hereafter known as “Val-Kill”). To classify the vegetation, 147 representative classification plots were sampled throughout the 2,029 acre (821 hectare) project area using traditional phytosociological methods (i.e., relevé sampling). The relevé plots were located and sampled primarily in 2003, 2004, and 2007. Three hundred and sixty vascular plant species were identified; the plot data were classified into 50 local vegetation associations using multivariate statistical analyses and the associations were described in detail. These local vegetation associations were also crosswalked to the U.S. National Vegetation Classification (USNVC) in order to provide a regional and global context for the park vegetation. The associations represented 43 USNVC alliances, 19 USNVC groups, 13 USNVC macrogroups, eight USNVC divisions and formations, and three USNVC subclasses and classes. A dichotomous field key was developed for these vegetation associations to assist with field recognition and classification. A map showing the locations of vegetation associations in the park was created, following the NVIP protocols. Digital geospatial databases were created for the ROVA project in its entirety. In early spring 2006, following the vegetation classification plot data analysis, the 2003 preliminary vegetation map of the Home of Franklin D. Roosevelt NHS (excluding Roosevelt Farm and Forest), Val-Kill, and Vanderbilt Mansion NHS was edited and refined to produce a revised vegetation map prior to thematic accuracy assessment (AA). In addition, in early spring of 2008, the 2007 Roosevelt Farm and Forest preliminary vegetation map was edited and refined to produce a revised vegetation map prior to AA. Using ArcMap 9.2 (ESRI 1999-2006), both preliminary maps were revised by editing polygon boundaries on-screen based on the classification plot data, field observations, classification analyses, aerial photography signatures, and topographic maps. These revised maps were used to plan an AA for each phase of the project. A total of 216 AA observations were made in 2006 and 2008. Following analysis of the AA data, a final vegetation type and land use map was created in 2009, resulting in corrected USNVC associations and Anderson Level I and II land use categories. User’s and producer’s accuracies for each USNVC map class and overall accuracies for USNVC classes were calculated and presented in contingency matrices. The overall accuracies for the USNVC portion of the map are 39.3% at the association level, 56.4% at the alliance level, 79.8% at the group level, 80.2% at the macrogroup level, 91.6% at the division and formation levels, and 94.1% at the subclass and class levels. Five NYNHP natural communities established within ROVA represent significant occurrences from a statewide perspective, they are: (1) hemlock-northern hardwood forest (combination of five hemlock-northern hardwood forest USNVC associations) on 183 acres (71 hectares); (2) diverse oak-tulip tree forest, northern portion is considered old-growth; (3) two vernal pool complexes in good ecological condition; (4) red-cedar rocky summit; and (5) freshwater tidal marsh with excellent species and physiognomic diversity.

Vegetation classification and mapping at Roosevelt-Vanderbilt National Historic Site

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