1970 IBP Moin Rweorch SIfs 

 \ - Artiticiol Monipulotion 

 (^ Intentivt and Disturbed 

 @ Troil and Oil 

 ® Community Gradient 

 @ Pond Area 



"1 r — 



ARCTIC OCEAN 



Pt. 

 Borrow/ 



Beaufort 

 S«o 



Nova I 

 Arctic Reseorctt Lob 



7l"23" 



Previous Reteorct< Site* 

 Primory Production 1969-70 

 Insect Activity l966-70aMicrei«et 



g) CRREL Study ond Wotershed Areos 

 Fertilizer Plots 



2)Primary Production, 1960-70 



T Lemming Troplinet 1956-70 



W Weir 



Chul<chi 

 Seo 



Borrow 

 (USWB) 



3km 



71*18' 



I56°45' I56'a?' 



Figure 2. Location map of major study sites involved in the 1970 Barrow ir.ifestigations. 



tion of on-going ecosystem modeling. In addition, these plots served as controls for a series of 

 manipulations or disturbances which were applied to the tundra. The manipulations served two 

 purposes. First, they provided an experimental approach to the study of ecosystem function. The 

 effects of manipulation of one component of the system may be traced to other components, thus 

 revealing pathways and functional forms of interactions between ecosystem components. Secondly, 

 manipulations, or controlled disturbances, were used to determine the sensitivity of the tundra 

 ecosystem to several classes of stress and to reveal the mechanisms of recovery or adjustment 

 following stress. This is directly applicable to the consideration of man's development of tundra 

 resources. 



Treatments 



Two classes of manipulations or disturbances were recognized in this effort: natural and 

 artificial. The natural manipulations are those which simulate naturally-occurring phenomena that 

 affect rates of nutrient and energy flow tlirough the ecosystem. 



Clip and clear. In the winter, which precedes a cyclic population high of brown lemmings, the 

 vegetation over large areas is clipped at the base by grazing lemmings. At the following melt-off 

 the remaining unconsumed portion falls to the ground and may be washed away by draining melt- 

 water. This causes a significant removal of nutrients from the local system, reduces the insula- 

 ting layer over the tundra soil, and alters the structure of the vegetative canopy and the litter 

 layer. On the clip and clear plot this was simulated by cutting the vegetation just above the moss 

 level, using hedge and lawn trimmers. The cut vegetation was gathered by hand, weighed, analyzed 

 for nutrient and caloric content, and used for mulch on another treatment. Two plots were treated 

 in this manner. One was sampled intensively, while the other was reserved for nondestructive 

 observations and sampling in subsequent years. 



7 



