Study Areas 
            
            
               
                 | 
               
               
                Locations of primary mId-level monitoring 
                    sites  | 
               
             
            
              - The Inventory and Monitoring 
                Program of the National Park Service has provided additional 
                funding for our efforts in the latter two areas. We also have 
                conducted surveys in the Neal Smith National Wildlife Refuge, 
                the Mississippi National River and Recreation Area, other portions 
                of Minnesota, Iowa, Illinois, and Wisconsin.
 
             
            Surveys 
            
              - We design our sampling to maximize the area over which we can 
                apply our results (area of inference), except when we look for 
                specific species in specific areas (targeted searches).
 
                 
               
              - One way we select sampling locations is to divide areas we intend 
                to sample into standard sized cells and then randomly select cells 
                to sample.
 
             
             
              
                 
                    | 
                 
                 
                   Voyageurs National Park divided into 
                      25-ha cells  | 
                 
               
             
             
             
            
              - We conduct surveys by listening for calls, visually 
                searching for animals, including using dip nets, and 
                by looking under cover-boards  according to standardized 
                methods (Heyer et al. 1994).  We also conduct targeted searches 
                and use minnow traps.
 
             
            
               
                  | 
                  | 
                  | 
               
               
                Surveying calling amphibians  | 
                Sampling using dip nets  | 
                Checking cover boards  | 
               
             
            
              - We measure several biological, physical, and chemical variables 
                during our surveys.
 
                 
               
              - Together these variables describe the numbers of individual 
                species we observe, their location, and the environmental conditions 
                at the time.
 
                 
               
              - During the course of our visual surveys, we evaluate animals 
                for obvious signs of ill health  and deformities.
 
               
             
            
               
                 
                  
                  Egg masses of wood frogs 
                  (Rana sylvatica) 
                  with algae and fungus | 
                                  Deformed northern leopard frog 
                  (Rana 
                  pipiens) | 
               
             
            
              -  
       
                        
 
                          
                             
                               | 
                             
                             
                              |   Using 
                                  a PDA to record data in the field  | 
                             
                           
                          We record data in personal digital assistants (PDA) in the field and upload those data to computers 
                          at the end of the day.
                          
                          
        
               
              - Our principal method for evaluating the distributions of species 
                is by analyzing the percent of the area we sampled that was occupied 
                by each species (MacKenzie et al. 2002, 2003).  All ARMI 
                regional scientists use the percent area occupied as their principal 
                statistic in describing data from mid-level monitoring.
 
             
            Approval by the 
              Animal Care and Use Committee 
            
              - We have obtained the review and approval of our methods by a 
                USGS Animal Care and Use Committee.
 
             
             
              Literature Cited 
            Heyer, W. R., M. A. Donnelly, R. W. McDiarmid, 
              L. C. Hayek, and M. S. Foster. 1994. Measuring and monitoring biological 
              diversity: standard methods for amphibians. Smithsonian Institution 
              Press, Washington, DC. 
               
              MacKenzie, D. I., J. D. Nichols, G. B. Lachman, S. Droege, J. A. 
              Royle, and C. A. Langtimm. 2002. Estimating site occupancy rates 
              when detection probabilities are less than one. Ecology 83(8):2248-2255 
               
              Mackenzie, D. I., J. D. Nichols, J. E. Hines, M. G. Knutson, and 
              A. B. Franklin. 2003. Estimating site occupancy, colonization, and 
              local extinction when a species is detected imperfectly. Ecology 
              84(8):2200-2207  |