Vegetation inventory project: Pu‘ukoholā Heiau National Historic Site

Cogan, Dan; Schulz, Keith; Benitez, David; Kudray, Greg; Ainsworh, Alison

Pu‘ukoholā Heiau National Historic Site (PUHE) encompasses approximately 32 ha (80 ac) on the western coast of the island of Hawai‘i. The park was established to preserve and protect three important ancient Hawaiian heiau or temples and other historical and cultural features. PUHE is situated on a vast lava field supporting 104 vascular plant species including examples of coastal strand and wetland native plants that are actively managed (NPS undated). Most of the remaining vegetation has been extremely altered over the years and consists primarily of non-native buffelgrass (Cenchrus ciliaris = Pennisetum ciliare) and kiawe (Prosopis pallida) trees/shrubs. To better understand the distribution of the plant assemblages located on this site, the National Park Service (NPS) Pacific Island Network (PACN) Inventory and Monitoring Program (I&M) started a vegetation inventory effort at PUHE in 2007. A three-year, four phase program was initiated to complete the task of mapping and classifying the vegetation at PUHE. Phase one conducted by PACN staff in 2008, collected 15 field plots and 13 observation points. In phase two, NatureServe’s Western Regional Office used this field data in conjunction with data collected at two other parks to classify six new plant associations for PUHE based on the revised US National Vegetation Classification (rUSNVC). Phase three, directed by Cogan Technology, Inc (CTI), produced a digital vegetation map and supporting accuracy assessment (AA) materials. In the final phase, PACN staff collected 57 accuracy assessment points in 2010 used to check and finalize the map. To produce the spatial database and map layer, 2006 0.6-meter, 4-band Quickbird satellite imagery was provided by PACN. By comparing the signatures on the imagery to field and ground data, 31 map units (14 vegetated, five geologic, and 12 land-use/land-cover) were developed and directly crosswalked or matched to their corresponding rUSNVC plant associations. The interpreted and remotely sensed data were converted to Geographic Information System (GIS) databases and maps were printed, field tested, reviewed, and revised. The final map layer was accessed for thematic accuracy by overlaying 57 independent accuracy assessment points. The final overall accuracy of the map layer was determined to be 97% with a Kappa value of 82% Products developed for PUHE are described and presented in this report. These include: A Final Report that includes keys to the vegetation and imagery signatures, AA information, and all of the project methods and results; A Spatial GIS Database containing spatial data for the vegetation, plots, and AA points; Digital Photos from the field sampling efforts; Metadata for all spatial data (Federal Geographic Data Committee -compliant); Vegetation Descriptions and Photo Signature Key to the map classes and associations/alliances.

Vegetation inventory project: Pu‘ukoholā Heiau National Historic Site

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