Ecological Archives A018-059-A6

Leigh G. Torres, Andrew J. Read, and Patrick Halpin. 2008. Fine-scale habitat modeling of a top marine predator: Does prey data improve predictive capacity? Ecological Applications 18:1702–1717.

Appendix F. Predictive results for hypothesis 1 (Ho 1).

Predictive capacity of dolphin distribution from 2005 survey data based on predictive maps created by the four tested model types in Ho 1 based on 2004 data for each zone. "Ratio of Foraging Sightings Selected" is the number of foraging sightings correctly predicted / number of foraging sightings observed. True Positive (TP), True Negatives (TN), False Negatives (FN), and False Positives (FP) were used to calculate Sensitivity (Se) and Specificity (Sp), which were then used to calculate the True Skill Statistic (TSS) for each prediction map. (See Methods for details.)

Observed data from 2005 survey date and zone

2004 Model type

No. sightings

No. absences

Ratio of foraging sightings selected

True positives (no. sightings selected)

True negatives (no. absences not selected)

False negative (no. sightings not selected)

False positive (no. absences selected)

Sensitivity: Commission errors TP/(TP+FN)

Specificity: Omission errors TN/(TN+FP)

TSS (Se+Sp -1)

TSS rank

22 July 2005 Atlantic

Dolphin ~ ENV + FISH

6

48

0/1

0

48

6

0

0

1

0

3

Dolphin ~ ENV

6

48

1/1

6

29

0

19

1.0000

0.6042

0.6042

1

Dolphin ~ FISH

6

48

0/1

1

32

5

16

0.1667

0.6667

-0.1667

4

FISH ~ ENV

6

48

0/1

4

35

2

13

0.6667

0.7292

0.3958

2

23 July 2005 Atlantic

Dolphin ~ ENV + FISH

6

61

0/3

0

61

6

0

0.0000

1.0000

0.0000

3

Dolphin ~ ENV

6

61

3/3

6

45

0

16

1.0000

0.7377

0.7377

1

Dolphin ~ FISH

6

61

0/3

1

32

5

29

0.1667

0.5246

-0.3087

4

FISH ~ ENV

6

61

3/3

3

50

3

11

0.5000

0.8197

0.3197

2

29 June 2005 Central

Dolphin ~ ENV + FISH

8

34

0/2

0

34

8

0

0.0000

1.0000

0.0000

2

Dolphin ~ ENV

8

34

0/2

0

34

8

0

0.0000

1.0000

0.0000

2

Dolphin ~ FISH

8

34

0/2

0

34

8

0

0.0000

1.0000

0.0000

2

FISH ~ ENV

8

34

2/2

4

30

4

4

0.5000

0.8824

0.3824

1

1 July 2005 Central

Dolphin ~ ENV + FISH

3

45

0/1

0

45

3

0

0.0000

1.0000

0.0000

2

Dolphin ~ ENV

3

45

1/1

1

41

2

4

0.3333

0.9111

0.2444

1

Dolphin ~ FISH

3

45

0/1

0

45

3

0

0.0000

1.0000

0.0000

2

FISH ~ ENV

3

45

1/1

1

41

2

4

0.3333

0.9111

0.2444

1

2 July 2005 Gulf

Dolphin ~ ENV + FISH

5

33

0/0

3

15

2

18

0.6000

0.4545

0.0545

1

Dolphin ~ ENV

5

33

0/0

0

33

5

0

0.0000

1.0000

0.0000

3

Dolphin ~ FISH

5

33

0/0

1

28

4

5

0.2000

0.8485

0.0485

2

FISH ~ ENV

5

33

0/0

0

30

5

3

0.0000

0.9091

-0.0909

4

3 July 2005 Gulf

Dolphin ~ ENV + FISH

4

35

1/1

3

8

1

27

0.7500

0.2286

-0.0214

3

Dolphin ~ ENV

4

35

0/1

0

35

4

0

0.0000

1.0000

0.0000

2

Dolphin ~ FISH

4

35

0/1

0

33

4

2

0.0000

0.9429

-0.0571

4

FISH ~ ENV

4

35

1/1

1

33

3

2

0.2500

0.9429

0.1929

1


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