Monteverde : Ecology and Conservation of a Tropical Cloud Forest

Table 5.1. Numbers of species of amphibians and reptiles by distributional zone in the Monteverde area.

Zone

Taxon

Amphibians
Caecilians (N = 2)
Salamanders (N = 5)
Anurans (N = 53)
Total (N = 60)
Percentage of N
Reptiles
Lizards (N = 29)
Snakes (N = 72)
Total (N= 101)
Percentage of N
Amphibians and reptiles (N = 161)
Percentage of N

1

1

0

18

19

31.7

14

31

45

44.6

64

39.8

2

1

2

23

26

43.3

15

41

56

55.4

82

50.9

3

1

3

27

31

51.7

10

30

40

39.6

71

44.1

4

0

5

28

33

55.0

5

21

26

25.7

59

36.6

5

1

1

28

30

50.0

9

17

26

25.7

56

34.8

6

1

1

32

34

56.7

16

34

50

49.5

84

52.2

Values are numbers of species for the decade preceding the 1987 crash of populations (see Appendix 8).

Table 5.2. Numbers of species of amphibians and reptiles by pattern of local distribution in the
Monteverde area.

Pattern of Distribution

Taxon

Amphibians
Caecilians (N = 2)
Salamanders (N = 5)
Anurans (N = 53)
Total (N = 60)
Percentage of N
Reptiles
Lizards (N = 29)
Snakes (N = 72)
Total (N= 101)
Percentage of N
Amphibians and reptiles (N = 161)
Percentage of N

Pacific

Slope only^3

(Zones 1 & 2)

1

1

8

10

16.7

11

31

42

41.6

52

32.3

Caribbean

Slope onlya

(Zones 5 & 6)

1

0

22

23

38.3

8

20

28

27.7

51

31.7

Both Pacific

and

Caribbean

Slopes

0

1

18

19

31.7

9

19

28

27.7

47

29.2

Highest

Elevations

Only

(Zones 3 & 4)

0

3

5

8

13.3

1

2

3

3.0

11

6.8

Reaching the

Highest

Elevations

(Zones 3 & 4)

1

5

32

38

63.3

10

31

41

40.6

79

49.1

Values are numbers of species for the decade preceding the 1987 population crash (Appendix 8). Only the first four categories of distribu-
tional patterns (columns) are mutually exclusive. Some species restricted to one slope in the Monteverde area inhabit both slopes if other
regions are taken into account.
"Extending in some cases to the highest elevations (Zones 3 & 4).

3 and 4; Fig. 5.6). Of the species missing throughout
1990-94, fewer than half would have disappeared if
the declines had affected any one of these areas in-
stead of the entire range of environments.

53. Geography and History

A species' susceptibility to extinction in a region de-

pends on its probability of disappearing from there

and its likelihood of recolonizing from neighbor-

ing regions. Hence, the vulnerability of a fauna de-

pends in part on broad patterns of geographic dis-

tribution, which are best understood in the context

of evolutionary history. In this section, I summar-

ize ideas concerning the historical biogeography of

the Middle American herpetofauna, examine the

Monteverde fauna in relation to them, and discuss

implications for susceptibility to regional or global

extinction.

155 Amphibians and Reptiles