Vegetation Inventory, Mapping, and Characterization Report, Organ Pipe Cactus National Monument: Volume I, Main Report
Studd SE , Galvin JB , Black JS, Hubbard JA . 2025. Vegetation Inventory, Mapping, and Characterization Report, Organ Pipe Cactus National Monument: Volume I, Main Report. Science Report. NPS/SR—2025/359. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2316014
From 2017 to 2020, the Sonoran Desert Network conducted a vegetation mapping and characterization project at Organ Pipe Cactus National Monument (ORPI) to update the 1981 vegetation map (Warren et al. 1981). This work, which is part of the National Park Service (NPS) Vegetation Mapping Inventory Program, aimed to provide park managers with a digital vegetation map meeting national standards for spatial and thematic accuracy and supporting regional and national comparisons. The 1981 map, which described 29 vegetation community types using the Brown, Lowe, and Pase classification system (Brown et al. 1979), served as a baseline for the update. Using fine-scale (30 cm) aerial imagery from ca. 2008, modern mapping methods, and new relevé plot data, vegetation communities were reclassified under the United States National Vegetation Classification System (USNVCS) at the association level. Map unit boundaries were aligned with the adjacent Cabeza Prieta National Wildlife Refuge (CPNWR) vegetation map boundaries where applicable and possible. The study area covers approximately 347,058 hectares (857,600 ac) of ORPI. Field surveys occurred primarily in winter 2017 and spring 2018, with two additional sampling rounds in spring 2019 and fall 2020 targeting under-sampled areas. Crews collected 323 classification plots and 1,065 photo points, resulting in the identification or update of 34 vegetation types at the USNVC association level. The final products include a geodatabase-based, vector polygon map compatible with Geographic Information Systems (GIS), supporting complex spatial–tabular analyses, concurrent data access, and future updates. These maps facilitate ecologically informed resource management and research, providing a foundation for monitoring vegetation dynamics and responding to disturbance events at ORPI.
- Type
- Published Report
- Authors
- Studd, Sarah; Galvin, Jeffrey; Black, Joseph; Hubbard, J.
- Date of Issue
- 2025-11
- Publisher
- National Park Service
- DOI
- 10.36967/2316014
- Units
- NRSS , ORPI
- Keywords
- Ajo mountain range, inventory, mapping, National Vegetation Classification Standard, native plants, Organ Pipe cactus, plant communities, vegetation classification, vegetation communities, vegetation inventory, wildfire
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Sparsely Vegetated Communities , Ecological Framework: Biological Integrity | Focal Species or Communities | Desert Communities , Ecological Framework: Biological Integrity | Focal Species or Communities | Shrubland Communities , Ecological Framework: Biological Integrity | Focal Species or Communities | Vegetation Complex