18 
Proposed 
actions 



Existing 
trend in 
local 
conditions | 
Existing 
abiotic 
conditions | 
Environmental 
policies 







Existing 
biotic 
Existing Future Future | os 
wildlife wildlife wildlife [-— 
conditions 
habitat habitat communi ty 






Existing 
wildlife 
conmuni ty 
Existing 
human 
conditions 
Fig. 14. A systems approach to the assessment of wildlife-land-use relations and the decision-making process (after Erickson et al. 1980). 
Table 5. Calculation of predicted change in the wildlife community caused by modification of vegetation 
cover types resulting from proposed land-use actions. 


Community comparison 




Hectares in block Guilds in habitat Present Proposed 
guilds x guilds x 
Polygon cover type Present Proposed Present Proposed hectares hectares 
A 200 30 6,000 
B 500 300 20 20 10,000 6,000 
C 100 15 1,500 
D 100 12 1,200 
E 100 10 1,000 
EF 700 15 10,500 
Total 19,700 16,500 

Change in composition and size of wildlife community associated with land use change = 19,700 — 16,500/19,700 = 16.2% = the 
potential reduction in wildlife values. 
Table 6. Impacts of heavy grazing on guilds and number of primary consumers in three types of upland vegetative cover. 




Nongrazed condition Heavily grazed condition 
No. of 
No. of Total no. potential guilds Total no. 
Vegetation cover type potential guilds primary consumers present primary consumers 
Upland grassland 28 42 2 12 
Upland shrubland 6 48 6 33 
Upland coniferous woodland 21 76 21 66 

4Impact is calculated only for guilds of primary consumers. 



