By
J.I. House & D.O. Hall
Division of Life Sciences, King's College London

 

Table 1. Previous estimates of area, biomass and NPP of savannas and grasslands

Source

Vegetation type

Area

          Biomass

                 NPP

Mkm2

Pg (DM)

kg (DM) /m2

Pg (DM) /yr

g (DM) /m2/yr

Whittaker & Likens (1973/5)

Savannas (includes tropical grasslands)

15

60

4 (0.2-15)

13.5

900 (200-2000)

Atjay et al (1979)

Dry savanna thorn forest

3.5

52.5

15.0

4.55

1300

Low tree/shrub savanna

6.0

45

7.5

12.60

2100

Dry thorny shrubs

7.0

35

5.0

8.40

1200

Grass dominated savanna

6.0

13.2

2.2

13.80

2300

Total

22.5

145.7

6.5

39.35

1749

Olson et al (1983)

Tropical dry forest and woodland (32)

4.7

73.3

15.6

6.00

1271

Tropical savanna and woodland (43)

6.7

44.9

6.7

7.33

1091

Succulent and thorn woods (59)

4.0

35.6

8.9

3.56

889

Semi-arid woodland or low forest (48)

0.9

11.1

11.1

0.89

977

Warm or hot shrub and grasslands (41)

17.3

50.2

2.9

15.56

899

Mediterranean types (46)

1.0

8.9

8.9

1.11

1111

Other dry or highland woods (47)

2.6

23.1

11.1

1.78

684

Total temperate and tropcial

37.3

247.1

6.6

36.22

972

Scholes & Hall (1996)

Drought-deciduous woodlands

4.6 (4.2)

34.4

8.3

5.2

1263 (462-1789)

Savanna

6.7 (6.0)

15.1

2.5

8.6

1426 (681-1941)

Succulent and thorn woods

3.9 (3.1)

1.4

2.5

2.7

856 (289-1370)

Eucalyptus and Acacia woodlands

0.9 (0.5)

7.8

2.5

0.4

733 (186-1242)

Total

16.1 (13.9)

58.7

4.2 (1.0-24)

16.9

1216 (440-4135)

This study

Tropical dry forest and woodland

4.7

64.7

13.7

6.0

1263 (462-1789)

Tropical savanna and woodland

6.7

31.8

4.7

9.6

1426 (681-1941)

Succulent and thorn woods

4.0

23.4

5.8

3.4

856 (289-1370)

Semi-arid woodland or low forest

0.9

6.3

7.0

0.7

733 (186-1242)

Warm or hot shrub and grasslands (tropical)

11.2

32.4

2.9

10.1

899

Total tropical

27.6

158.5

5.75

29.7

1078

Notes:

DM = dry matter; Pg = 10^15g. Carbon content assumed to be 0.45 DM

Olsen et al. (1983) categories include tropcial and temperate tree-grass mixes (not montane), Scholes & Hall (1996) areas based on Olsen et al. (1983) classes 32, 43, 48, and 59, estimated undistrubed area (i.e., still under natural vegetaion, not urban/agriculture/degraded) shown in brackets and used for biomass and NPP calculations, although corrected totals shown here due to inconsistency in use of land areas in original paper. NPP calculated using the relationship between WAI and total NPP shown in Fig. 16-3 and discussed in text.

This study land areas from Olson et al. (1983), tropical portion of "warm and hot shrub and grasslands" (between 30'N and 30'S) calculated by Dale Kaiser, ORNL, USA. Biomass average of Table 16-3 based on Scholes & Hall (1996) (explained in text), and Olson et al. (1983) values.
  ACKNOWLEDGEMENTS

Many thanks to Bob Scholes (CSIR, South Africa), Xavier Le Roux (INRA, Clermont-Ferrand, France), Jonathan Scurlock (ORNL, USA) and Joe Scanlan (Department of Natural Resources, Queensland, Australia) for providing information and making corrections to the manuscript. Dale Kaiser & Sonja Jones (ORNL, USA) for calculating tropical % of the Olson et al (1983) "grasslands" category.

Sadly, David Hall passed away in August 1999 before this chapter was published. His knowledge and love of savannas was only surpassed by his eagerness to learn and teach.

 
REFERENCES
Table 2: Broad plant functional types found in African savannas (from Scholes et.al., 1997)
Table 3: Biomass reported for tropical grasslands and savannas
Table 4: Primary production reported for tropical grasslands and savannas
Table 5: Biophysical properties, fluxes and efficiencies
Figure 2: The relationship between total NPP and aboveground NPP

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