Guanaco abundance and monitoring in Southern Patagonia: distance sampling reveals substantially greater numbers than previously reported

Zoological Studies

Table 3 Sampling effort needed to monitor guanaco population trends in Santa Cruz province, southern Patagonia

		Monitoring program scenario
		50% in 5 years				50% in 10 years
		Increase		Decrease		Increase		Decrease
		α = 0.2	α = 0.3	α = 0.2	α = 0.3	α = 0.2	α = 0.3	α = 0.2	α = 0.3
	Relative abundance	80	50	>120	90	40	20	80	60
All guanaco groups	Low	110	80	>120	>120	80	40	120	80
	Medium	70	50	120	80	30	20	80	50
	High	40	30	70	50	20	20	40	30
Breeding groups	Low	>120	>120	>120	>120	>120	>120	>120	>120
	Medium	>120	>120	>120	>120	>120	>120	>120	>120
	High	60	40	110	80	30	20	70	40
Non-breeding groups	Low	>120	>120	>120	>120	120	>120	80	>120
	Medium	>120	70	>120	>120	60	40	120	90
	High	70	50	120	80	20	20	70	50
Solitary individuals	Low	>120	120	>120	>120	90	60	>120	120
	Medium	60	40	120	80	30	20	60	50
	High	50	30	90	60	30	20	50	40
Breeding groups		>120	>120	>120	>120	>120	>120	>120	>120
Non-breeding groups		>120	100	>120	>120	70	50	>120	90
Solitary individuals		90	60	>120	100	40	30	90	60

Sampling effort is expressed as the number of randomly located 30-km survey transects needed to attain the desired power of 1-β = 0.80 for each hypothetical scenario. Separate estimates of sampling effort are also given for areas with different combinations of classes of guanaco relative abundance and type of guanaco group. Estimates are also given after pooling all classes of relative abundance.