Inventory and Survey Methods for Nonindigenous Plant Species (PDF)

Chapter 1 • Getting StartedClose examinationmay be neededto identify plantscorrectly. Photocourtesy of LisaRew.goal must be to maintain an adequate amount of forage. AnNIS management objective for such an area might includereducing the amount of NIS to less than 10%. Constraintson meeting NIS management objectives must also beconsidered; for example, having a large area to manage butvery little staff. Constraints need to be revisited as inventory/survey objectives are defined and methods are selectedbecause they influence the management, inventory/survey,and monitoring plans.To identify NIS management objectives—for example,to minimize NIS density, area, and spread, or to eradicatethe NIS completely—the following questions should beanswered:• What is the area of interest? What size is it? How much ofit must be managed?• What are the land use goals for that area (e.g., grazing,wildlife habitat, logging, recreation, native communityconservation)?• What are the desired plant community conditions? Forexample, is at least 90% cover/abundance of nativevegetation desired?• Are NIS present? How might they affect achieving theland use goals and the desired plant community?After the NIS management objectives are identified, constraintsto consider include:• Cost and type (skill level) of labor required for datacollection and data interpretation• Time available for data collection (e.g., length of fieldseason)• Size, land type, and topography of management area• Access and travel restrictions• Availability of equipment• Level of precision and accuracy needed in identifying andmapping NIS• Regulatory considerations affecting management (e.g.,threatened and endangered species, regulation of tools,regulation of habitats)• Other constraints such as aesthetic values, public opinion,need to maintain wildlife habitatWhen questions pertaining to the NIS managementobjectives are answered and constraints considered, it isthen possible to establish the inventory/survey objectives,determine the inventory/survey methods, and decide whatdata to collect. These are the critical steps for selecting themost appropriate and efficient inventory/survey method.Questions to address before selecting an inventory/surveymethod include:• What is the purpose of the inventory/survey? How willit help to meet land use goals and NIS managementobjectives?• How will the data be used to achieve the land use goalsand NIS management objectives?• How much information does the manager need about theNIS patches? For example, their size, density, and cover;or simply whether a particular NIS is present or absent?• At what scale (extent and resolution) does the inventory/surveyneed to be conducted within the managementarea? If it is the entire area, then it will be an inventory;otherwise, it will be a survey. Decide what resolution, orminimum mapping unit, is appropriate (e.g., 10 m 2 , 20m 2 , 50 m 2 , a single section).To determine whether NIS management objectives arebeing attained, monitoring must take place. It is thereforeimportant at the onset of a project to consider how thefollowing monitoring objectives will influence the inventory/survey method. Monitoring may be needed to determine:• If the population parameters are changing (e.g., area,density, cover.)• If the population parameters are changing according tothe location where the NIS is found (in certain habitats,disturbed areas, etc.)• If new populations are establishing, and if so, what thespread vectors are (e.g., roads, paths, or streams)• What impact the NIS may be having on the surroundingvegetation or ecosystem (changes in plant species compositionor abundance may be the most observable response)10Inventory and Survey Methods for Nonindigenous Plant Species