Use of threat status as a tool to assess condition of natural resources and as a measure of success for conservation actions can be a cheaper and simpler approach than direct measures of biological resources (Salafsky and Margoluis 1999). However, establishing direct links between threats and the condition of ecological resources can be difficult (Salafsky and Margoluis 1999, Parrish et al. 2003). The extent of the difficulty is reflected in the landscape feature and SGCN summaries, which frequently identify the need for more information on the effects of threats on species, ecological communities and ecosystems. Therefore, monitoring of threat status should be done in conjunction with direct ecological research.
Data and information are already collected for some threats, often for other purposes. These data need to be examined and evaluated for their utility for wildlife conservation. Information on habitat loss, population growth, development patterns, social attitudes, recreation, and invasive species introduction and establishment rates are already collected by various public agencies and NGOs and may be suitable for monitoring of threats or natural processes. For instance, spatial analysis of remotely sensed land-cover data, such as those collected for the DNR's IFMAP system, can be used to assess extent of landscape fragmentation, and streamflow data, such as that collected by the USGS, can be used to assess hydrologic alteration.
Some threats are more difficult to measure directly and may be more easily quantified by using biological indicators (e.g., indicator species or community metrics). Measuring success in threat abatement through biological indicators or in combination with them can help to resolve problems associated with linking threats to biological resources.
Threat monitoring must be implemented at multiple scales in a coordinated manner. For some threats, existing data will be appropriate for statewide or regional assessments of change, but local-level assessments may require additional data collection. Assessments of local changes in habitat using currently available land-coverage data may be inappropriate even though the same approach is suitable for regional analyses (Donovan et al. 2004). Monitoring of invasive species requires efforts at statewide levels in conjunction with local efforts to ensure that species are identified immediately after they are introduced or become established, because this is the most effective and efficient time to implement conservation actions to control them.
The highest priorities for threat monitoring at a statewide scale include those threats identified as statewide priority threats. The most severe threats within ecoregions and lake basins have also been identified. Efforts should be made to ensure that these threats are monitored at appropriate scales.