Inventory and Survey Methods for Nonindigenous Plant Species (PDF)

Chapter 5 • Tiered Sampling Method: Nevada’s Protocol1. Inventory all roads, trails, byways, railways, utilitycorridors, and/or other transportation systems. Make surethat the chosen method of travel allows the surveyor tofind any NIS populations along the chosen route. If sightdistances are adequate, then traveling in or on slow-movingvehicles will suffice (Figure 1). If not, the route needsto be traveled on foot or by some other means, such asall-terrain vehicle (ATV) or bicycle, that will allow a morecomplete view of the area (Figure 2). Inventory resultsshould reflect the route traveled and the approximate sightdistance at which NIS populations can be determined.2. Inventory all known seeps, springs, streams, dry streambeds,riparian systems, irrigation canals, stock ponds,wetlands, and/or reservoirs, etc., that are likely to containtarget NIS. The locations of these are downloaded fromthe GIS to the GPS to ensure that all locations are visitedand inventoried. As above, take care that the method oftravel enables the surveyor to find any NIS populationsalong the route, so that the results reflect the route traveledand approximate sight distances.3. As important as documenting where NIS infestationsoccur is documenting where they do not occur. Whileinventorying disturbed areas, record all paths, routes, orareas inventoried with the GPS unit and database libraryin order to document places inventoried where no NISinfestations were found (Figure 3). The Nevada protocolcalls for turning on the GPS and database library wheninventory begins, with all the routes traveled recorded.Any NIS populations are noted in the GPS databaselibrary with all associated database fields. Areas withoutNIS are not noted specifically, but because we are recordingour route at 100-ft (30.5-m) intervals throughout theinventory, we have presence and absence data for eachNIS. We can then calculate the frequency of each NIS inthe area inventoried.4. Additional disturbed areas may be specifically selectedfor inventory depending on other management objectivesand considerations such as the probable presence of rareor endangered species and/or the prevention of NIS spreadinto rare habitat.5. Data collection and storage is an essential step in each tierof the three-tiered process (Figure 4). In Nevada, the Tier Idata are collected by the user (e.g., county agents, governmentagencies) and sent to a centralized database.▲ Figure 1. Conducting inventory/survey from a slow-moving vehicle.44Inventory and Survey Methods for Nonindigenous Plant Species