Inventory and Survey Methods for Nonindigenous Plant Species (PDF)

Chapter 2Data ManagementMandy TuIntroductionInvasive nonindigenous plant species are one of thebiggest threats to the successful management ofour natural resources. Not only do nonindigenousspecies (NIS) negatively impact our native species,communities, and ecosystems, but keeping track ofNIS data can be challenging as well. In many instancesNIS invasions can be reversed, halted, or slowed, andin certain situations, even badly infested areas canbe restored to healthy systems dominated by nativespecies (Chornesky and Randall 2003). In order todocument such successes and failures, inventory/surveydata are initially required to assess the currentcondition, followed by monitoring data to documentchanges over time. Good record keeping of the location,extent, and abundance of NIS, and the impactsof those NIS, management actions, and restorationefforts is essential for efficient NIS management. Inaddition, tracking the success or failure of such effortscan be used adaptively to improve the effectiveness offuture management approaches.Why Manage NonindigenousPlant Species Data?Natural resource managers need to know where the NIS ofinterest are in their management area. This can be achievedwith one of the inventory/survey methods described inthis book. However, once NIS inventory or survey data arecollected, they must be managed if they are to fulfill anypurpose. The most effective way to manage inventory/surveydata is in digital format on a computer. A digital copy canbe more easily kept current and shared with others thanpaper copies. Digital data management enables managers toimmediately find all past NIS individuals/patches that havebeen mapped and treated and ensures that data will not belost as a result of personnel changes.Inventory/survey data must address the land managementgoals. Generally these data will include knowledge of thedistribution and the degree of infestation (cover, density,etc.) of NIS populations (inventory/survey data) or theirspread (monitoring data). Evaluation of such data allowmanagers to allocate time and other resources in the moststrategic and effective way, and this is more easily done withdigital rather than paper versions of the data. Additionally,if data are not recorded and organized in an easily decipherableformat, site knowledge may be lost. With all NISinventory/survey and monitoring data in one easily accessibleand translatable format, managers can get a “snapshot”picture of the current NIS situation and potential dispersalpathways/vectors and determine changes in populations.Equipped with these data, managers can:• Strategically spend resources to get the most work done atthe lowest cost• Develop strategies focused on prevention and earlydetection/rapid response, rather than control andcontainment only• Share data at multiple scales with other partners• Predict potential NIS problems and likely sites of invasion• Generate awareness of NIS issues with the public• Attract fundingThe three examples provided below demonstrate thatwhen inventory/survey data are collected and maintained ina digital format, it can be easily accessed and immediatelyused in a variety of applications to help meet NIS managementobjectives.Snapshot of the Distribution and Abundance of NISA one-time survey or inventory for NIS can produce a mapof the distribution and abundance of NIS populations in thesampled areas. Some inventory/survey methods also allowpredictive maps to be made (see Chapter 6) showing wheretarget NIS might be found over an entire area of interest, andwhere future inventories/surveys should be conducted.Figure 1 shows an example “snapshot” from the SanPablo Bay National Wildlife Refuge in California, in whichthe distribution and abundance of only one NIS, perennialpepperweed (Lepidium latifolium), has been mapped (shownin red). A few things are immediately apparent. There areseveral small and large infestations, the infestations appearto start right at the edge of the impoundments/levees, andsome of the large infestations have several smaller outliers.From this map, in which only the distribution of perennialpepperweed is shown, and the value of certain parcels ofproperty or the presence of rare and endangered speciesis not designated, a management strategy for perennialpepperweed can still be developed. The small outlierpopulations will be controlled first, while the larger populationsare kept in check to prevent spread, and the potentialpathways and vectors of perennial pepperweed invasion aredeciphered. For example, does the invasion appear to spreadalong the impoundment roads, which could be related tothe movement of equipment, or does the species appear tobe spread by water, which would restrict it to waterwaysor flood-prone areas? Identifying possible vectors and/orpathways of dispersal is key to preventing new invasions. Itis equally important to identify uninfested areas, since it ismuch easier to implement an early detection/rapid responseprogram than to control well-established NIS.17Inventory and Survey Methods for Nonindigenous Plant Species