InUiidiiclion — Our Livinii Resources 



Figure. Northern pintail duck 

 (Anas acuta) population data 

 demonstrate the importance of 

 long-temi data sets. Annual fluctu- 

 ations (e.g., 1967-70 ) reflect year- 

 ly fluctuations in breeding success 

 that may have been caused, for 

 example, by differences in rainfall 

 and the abundance of temporary 

 wetlands for nesting habitat. 

 Short-term data sets can give erto- 

 neous conclusions; for example, if 

 only data from 1964 to 1972 were 

 available, managers might con- 

 clude that populations were 

 increasing. The long-terai data, 

 however, describe a statistically 

 and biologically significant popu- 

 lation decline. (Source: U.S. Fish 

 andWildhfe Service, 1993. Status 

 of Waterfowl and Fall Flight 

 Forecast.) 



produce data on the condition of species or 

 ecosystems for a single point in time; trend 

 studies, in contrast, provide a chronological or 

 geographic picture of change in the same 

 resource. Either can measure a number of dif- 

 ferent biological indicators, such as population 

 size, distribution, health, or physiological fac- 

 tors such as breeding productivity or seed pro- 

 duction. Species composition, biodiversity, and 

 age and physical structure are all important 

 indicators of ecosystem status. 



Inventory and monitoiing programs can pro- 

 vide measures of status and trends to determine 

 levels of ecological success or stress; if such 

 programs are appropriately designed, they can 

 give early warnings of pending problems, 

 allowing resource managers to take remedial 

 action while there are more management 

 options. These earlier options are less severe 

 than if management response is delayed until 

 problems are critical, such as when a species 

 becomes endangered. 



One of the challenges resource managers 

 face is to detect long-term trends because such 

 trends are often masked by short-term, random, 

 or undirectional variations (Figure). Plant and 

 animal species often vary greatly in abundance, 

 distribution, or fecundity as a result of forces 

 that include annual or seasonal variations in cli- 

 mate; chance events such as Hoods and hurri- 

 canes; effects from predators or competing 

 species; and even internal physiological 

 processes. Some variations appear totally ran- 

 dom; many are cyclic, recurring periodically; 

 and others are long-term in one predominant 

 direction. Scientists have many ways to deter- 

 mine whether apparent changes are biologically 

 and statistically significant, although it is often 

 difficult to detect such trends in their early 

 stages. The design of monitoring programs 

 should address issues such as the number of 

 samples needed, the sampling technique, and 

 the frequency and duration of sampling. All are 

 critical factors in determining the sensitivity of 

 the monitoring program to detect directional 



55 60 65 70 75 80 85 90 



Year 



change. Data collected in a standard or consis- 

 tent fashion over many years are especially crit- 

 ical to identify and document trends. 



National Inventory and 

 Monitoring Programs 



A number of inventory and monitoring pro- 

 grams have been underway for several to many 

 years in various agencies (Table). Historically, 

 the federal government has been responsible for 

 monitoring the status and trends of migratory 

 species as well as those resident on federal 

 lands. In addition, the federal government mon- 

 itors habitat conditions on federal lands and, 

 under some circumstances, private lands. Some 

 of the monitoring programs also require 

 international cooperation because many of the 

 migratory species monitored cross international 

 boundaries. 



States have monitored resident species and 

 often cooperated in surveys of migratory 

 species. A significant problem with these efforts 

 has been that often the individual agencies or 

 states have used different monitoring proce- 

 dures and standards, and the results are not 

 comparable from area to area or among differ- 

 ent agencies. 



The private sector, including particularly 

 The Nature Conservancy, has worked with 

 states to establish Heritage Programs that mon- 

 itor the distribution and abundance of selected 

 species. This effort has resulted in standardized 

 procedures. 



Most inventory and monitoring programs 

 were established for a specific puipose. usually 

 relating to management of natural resources. 

 For example, the efforts to monitor duck popu- 

 lations started 35 years ago to improve the basis 

 for hunting regulations, and the National 

 Wetland Inventory was started in 1979 to deter- 

 mine the condition and rate of wetland loss. 

 Until recently, few. if any. of these programs 

 were intended or have been used to provide 

 broad-based and predictive tools that could help 

 resource managers identify future resource 

 problems. 



The National Biological Service has the 

 responsibility for developing information on the 

 status and trends of our nation's plants and ani- 

 mals and the habitats on which they depend. It 

 will achieve this by building on the inventory 

 and monitoring activities existing in the state, 

 federal, and private sectors. The national status 

 and trends effort will continue to depend upon 

 the contributions of these existing programs, 

 and NBS will avoid duplicating programs 

 already under way. Its role will be to coordinate 

 the activities of different agencies into a com- 

 prehensive assessment of our living resources. 



