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Table 2 Density and population size

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

Social unit

Relative abundance

Contacts

g ( w )

Groups/km 2

D (ind/km 2 )

Lower limit

Upper limit

CV

N

 

Low

11

0.15

0.0431

0.4413

0.1289

1.5101

69.04

26,173

Medium

103

0.13

0.2249

2.3047

0.8001

6.6393

57.77

200,020

High

64

0.10

0.3455

3.5409

1.2066

10.3910

58.95

270,700

Breeding group

Pooled

178

0.12

0.2179

2.2328

0.7839

6.3600

57.04

496,900

 

Low

18

0.14

0.0347

0.3712

0.1792

0.7681

37.81

22,013

Medium

129

0.15

0.1413

1.5128

0.9988

2.2914

21.29

131,290

High

100

0.19

0.2656

2.8437

1.6483

4.9059

27.77

217,400

Non-breeding group

Pooled

247

0.17

0.1556

1.6658

1.1253

2.4657

20.02

370,710

 

Low

29

0.06

 

0.0814

0.0434

0.1643

36.72

4,828

Medium

159

0.05

 

0.2538

0.1495

0.4309

27.42

22,029

High

111

0.12

 

0.4297

0.2375

0.7774

30.76

32,849

Solitary individuals

Pooled

299

0.08

 

0.2683

0.1595

0.4512

26.90

59,706

 

Low

7

0.13

0.0396

0.0910

0.0201

0.4130

89.33

5,402

Medium

86

0.14

0.2766

0.6364

0.1479

2.7370

85.15

55,236

High

47

0.22

0.3665

0.8434

0.1964

3.6225

85.04

64,481

Undetermined

Pooled

140

0.17

0.2443

0.5622

0.1328

2.3801

83.91

125,120

 

Low

63

0.14

0.1920

1.1228

0.6663

1.8920

26.89

66,590

Medium

464

0.14

4.7028

4.7028

3.1082

7.1156

21.32

408,160

High

315

0.17

1.3236

7.7419

4.9303

12.1570

23.16

591,870

All contacts

Pooled

842

0.15

0.8194

4.7928

3.2704

7.0240

19.65

1,066,600

  1. Estimates of guanaco density (D) and population size (N) for each observable social unit and in three classes of expected relative abundance of guanacos in Santa Cruz Province, southern Patagonia, during the 2004 and 2005 breeding seasons. The number of intervals used to fit the most parsimonious detection function was 10 in all cases. g(w) is the value of the detection function at the truncation distance (600 m for solitary guanacos, 500 m for other social units). Upper and lower limits of 95% confidence intervals for density estimates are reported. CV coefficient of variation of density estimates.