Vegetation inventory, mapping, and characterization report, Tonto National Monument

Studd, Sarah; Hubbard, J.; Fallon, Beth; Drake, Sam; Villarreal, Miguel

A vegetation classification, description, and mapping effort was conducted at Tonto National Monument (NM) from 2008 to 2011 by the Sonoran Desert Network in cooperation with the University of Arizona’s Office of Arid Lands Studies (OALS). This project was completed under the National Park Service (NPS) Vegetation Inventory Program, which aims to com-plete baseline inventories at more than 270 national park units. The vegetation map data were collected to provide park managers with a digital map product that met national standards of spatial and thematic accuracy, while also placing the vegetation into a regional and even national context. For Tonto NM, as well as other network parks, comprehensive vegetation data inform park management decisions and provide a foundation upon which to develop and implement specific research and monitoring programs. The data standard was designed to facilitate the production of uniform statistics about vegetation across the nation, enable the translation of data collected at various scales, and allow data sharing, aggregation, and comparison across regions. Vegetation mapping and characterization comprised three major field phases: (1) concurrent, field-based data collection and mapping from aerial imagery, (2) development of vegetation community types at the National Vegetation Classification association level, and (3) map accuracy assessment. A survey of all classification plots and polygons was completed during March and April 2009. Vegetation association descriptions were drafted from these data to meet the National Vegetation Classification System (NVCS) standard, and were applied to each of the mapped areas. A formal accuracy assessment (AA), completed in spring 2010, consisted of a census approach in which each map unit (polygon) was assessed in its entirety. This effort sought to evaluate the per-class accuracy for map users and was conducted by a separate team in an unbiased manner. Following the AA, final products were developed, including this report, a digital map, and full vegetation descriptions. A total of 23 vegetation associations were described and mapped at Tonto NM during this project, ranging from paloverde - jojoba-dominated wooded shrublands in the lower al-luvial fans to Sonoran scrub oak - mountain mahogany shrublands at the upper-elevation mountain ridge sites. The vegetation is relatively diverse for a monument of only 453 hectares (1,120 ac), with influences of the Sonoran Desert and Colorado Plateau seen in the flora. Overall, the vegetation can be separated into a few broad categories, from most abundant to least, as follows: transitional Sonoran desert scrub, semi-desert shrublands, montane shrub-lands, mesquite and acacia washes and woodlands, and riparian forest. After accuracy assessment (AA), four associations were combined into two map classes, as they were not distinguished in the field during the AA effort. The final map and spatial data products have symbolic representation showing both the map unit and association level data. For all but these two merged associations (Simmondsia chinensis - Lycium fremontii Shru-bland and Parkinsonia microphylla / Simmondsia chinensis - Ericameria laricifolia Shrubland), the map class is exactly equal to the association. Overall accuracy for all classes was 80%, with a Kappa (a measure of overall accuracy minus chance agreement) of 79%. Individual class accuracies varied from 50 to 100%. Three of the associations had accepted corollaries within the National Vegetation Classification (NVC) at time of writing; all others were de-scribed solely from data collected at Tonto during this project. The vegetation map, designed to facilitate ecologically based natural resources management and research, is in digital format within a geodatabase structure that allows for complex relationships to be established between spatial and tabular data, and makes accessing the product easy and seamless.

Vegetation inventory, mapping, and characterization report, Tonto National Monument

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