Consumers 



Other than the observations made at Prudhoe Bay, reported in Section II of this report, the 

 only detailed studies of the consumer populaticms on the bioenvironmental gradient were made at 

 two sites in the taiga woods at Fairbanks. One site, an open white birch association on a hill- 

 side with an understory primarily composed of grasses, has been under intensive study since 1968. 

 Study of the second site was initiated in summer 1970 in the hot-pipe control area, where small 

 mammal populations were censused in both the birch and the spruce stands. 



The immediate goal is to follow the energy flow from the producers through the small herbivore 

 populations in the three areas. There are three primary objectives: 1) net primary production, 

 2) net and gross production of small herbivore populations, and 3) herbivore utilization of net 

 primary production. 



The small herbivores present are the meadow voles {Microtus oeconomus and Microtus 

 pennsylvanicus), the red-backed vole (Clethrionomys rutilus) and the jumping mouse {Zapus hud- 

 sonicus). Unfortunately, the two species of Microtus cannot be distinguished in the field. Autopsy 

 of snaptrapped specimens shows that Microtus oeconomus constitutes 90% of the Microtus popula- 

 tion. 



Small-mammal numbers are determined with live-trapping (capture-recaptured) and snap-trapping 

 techniques, according to the following schedule: 



Area 



Size 



Time trapped 



Open birch - grassland (3-mile Steese Highway) 



Grid A (Live) 



100 stations at 

 5-m intervals 



Every 2 wks in summer (snow- 

 free) 



4 wks in winter (snow pres- 

 ent) 1968-1970 



Grid B (Live 

 Control 



100 stations at 

 5-m intervals 



2 wks in summer 1969-1970 



Grid E (Live) 

 Control 



100 stations at 

 5-m intervals 



2 wks in summer 1970 



Grid F (Snap) 



256 stations at 

 10-m intervals 



Aug 1969 - May 1970 

 Sept 1970 



Grid C (Live) 

 Birch 



Hot-pipe control 



64 stations at 

 10-m intervals 



2 wks in summer 



Grid D (Live) 

 Spruce 



64 stations at 

 10-m intervals 



2 wks in summer 



4 wks in winter 1970 



110 



