Our Livint' Resources — Alaska 



339 



Caribou 



We periodically photographed and censused 

 the PCH in July from 1972 to 1992. To deter- 

 mine when the caribou were optimally aggre- 

 gated for photographing, we monitored the for- 

 mation and distribution of large postcalving 

 aggregations by using intensive aerial recon- 

 naissance, radio tracking, and satellite teleme- 

 try. 



We estimated the sex and age structure of the 

 PCH during the postcalving aggregation period 

 from aerial and ground counts in 1988, 1989, 

 1990, and 1992. We estimated annual survival 

 of cows and calves by using aircraft and satel- 

 lites to periodically track a sample of animals 

 fitted with radio transmitters. 



Muskox 



We closely monitored the distribution, com- 

 position, and size of the muskox population by 

 using radio transmitters, tags, and intensi\e aer- 

 ial and ground surveys. We surveyed muskox at 

 4-8 week intervals in 1987-93 to determine their 

 locations. An average of eight flights per year 

 were tlown. We conducted no tlights from late 

 November to late January because of severe 

 winter weather and low light conditions. 



We also determined sex and age composition 

 from the ground counts. We conducted total 

 counts of the population annually from 1972 to 

 1993 during aerial surveys and ground counts. 



Fig. 1. Arctic National Wildlife Refuge in northea.stem Alaska. 



Herbaceous types 



j J Wet sedge tundra 



I^HJ Wet/moist sedge lundra 

 I I Moist/wet tundra 

 r 1 Moist sedge-willow tundra 

 ■BH IVIoisI sedge-dryas tundra 

 I I Moist sedge-tussock lundra 



Shub-dominated types 



K";^ Moist stirub lussock/watertrack 



I Moisl stirub/tiigh-center polygon 



^H Moist shrub lundra 



IH Dryas-graminoid alpine tundra 



^^1 Ripanan shrub 



^^1 Dryas River Terrace 



Other types 



■■ Partially vegetated 



I [ Barren 



^^^_ Ice 



i ^ Wafer 



^^1 Shadow 



Fig. 2. Land-cover classes on the Arctic National Wildlife Refuge in northeastern Alaska. 



