266
The Biology of Sea Turtles, Vol. II
TABLE 10.2
Carrying Capacities for Green Turtles on Thalassia testudinum Pastures in the Caribbean
Intake
kg DM Thalassia • (kg Green Turtle) –1
• year –1
0.74 a
1.17 b
1.77 c
Thalassia
productivity
kg DM • ha –1
year –1
kg Turtle • ha –1
Number of Turtles
in Caribbean d
kg Turtle • ha –1
Number of Turtles
in Caribbean d
kg Turtle • ha –1
Number of Turtles
in Caribbean d
Heavy grazing e
292
38,544,000
185
24,420,000
122
16,104,000
Moderate grazing f
4,439
585,948,000
2,808
370,656,000
1,856
244,992,000
Notes:
Calculations are based on three levels of intake estimated by three different methods and on two levels of T. testudinum
productivity. DM = dry mass.
Sources:
From Bjorndal, K.A., A.B. Bolten, and M.Y. Chaloupka. 2000. Green turtle somatic growth model: evidence for density dependence. Ecol. Appl.
10:269–282.
With permission.
a
From Bjorndal, K.A. 1982. The consequences of herbivory for the life history pattern of the Caribbean green turtle, Chelonia mydas
. Pages 111–116 in K.A. Bjorndal,
editor. Biology and Conservation of Sea Turtles
. Smithsonian Institution Press, Washington, DC; based on calculation of energy budget for adult female.
b
From Bjorndal, K.A. 1980. Nutrition and grazing behavior of the green turtle, Chelonia mydas
. Mar. Biol.
56:147–154; based on indigestible lignin ratio and daily
feces production.
c
From Williams, S.L. 1988. Thalassia testudinum
productivity and grazing by green turtles in a highly disturbed seagrass bed. Mar. Biol.
98:447–455, based on
estimates of daily bite counts and bite size.
d
Based on 6,600,000 ha Thalassia
in the Caribbean (from Jackson, J.B.C. 1997. Reefs since Columbus. Coral Reefs
16:S23–S33) and turtle size = 50 kg.
e
216 kg DM • ha –1
• year –1
. (Recalculated from Williams, S.L. 1988. Thalassia testudinum
productivity and grazing by green turtles in a highly disturbed seagrass
bed. Mar. Biol.
98:447–455, Table 4. )
f
3,285 kg DM • ha –1
• year –1
. (From Zieman, J.C., R.L. Iverson, and J.C. Ogden. 1984. Herbivory effects on Thalassia testudinum
leaf growth and nitrogen content.
Marine Ecology Progress Series 15:151–158.)
1123 book.book Page 266 Monday, November 11, 2002 11:11 AM
The Biology of Sea Turtles, Vol. II
TABLE 10.2
Carrying Capacities for Green Turtles on Thalassia testudinum Pastures in the Caribbean
Intake
kg DM Thalassia • (kg Green Turtle) –1
• year –1
0.74 a
1.17 b
1.77 c
Thalassia
productivity
kg DM • ha –1
year –1
kg Turtle • ha –1
Number of Turtles
in Caribbean d
kg Turtle • ha –1
Number of Turtles
in Caribbean d
kg Turtle • ha –1
Number of Turtles
in Caribbean d
Heavy grazing e
292
38,544,000
185
24,420,000
122
16,104,000
Moderate grazing f
4,439
585,948,000
2,808
370,656,000
1,856
244,992,000
Notes:
Calculations are based on three levels of intake estimated by three different methods and on two levels of T. testudinum
productivity. DM = dry mass.
Sources:
From Bjorndal, K.A., A.B. Bolten, and M.Y. Chaloupka. 2000. Green turtle somatic growth model: evidence for density dependence. Ecol. Appl.
10:269–282.
With permission.
a
From Bjorndal, K.A. 1982. The consequences of herbivory for the life history pattern of the Caribbean green turtle, Chelonia mydas
. Pages 111–116 in K.A. Bjorndal,
editor. Biology and Conservation of Sea Turtles
. Smithsonian Institution Press, Washington, DC; based on calculation of energy budget for adult female.
b
From Bjorndal, K.A. 1980. Nutrition and grazing behavior of the green turtle, Chelonia mydas
. Mar. Biol.
56:147–154; based on indigestible lignin ratio and daily
feces production.
c
From Williams, S.L. 1988. Thalassia testudinum
productivity and grazing by green turtles in a highly disturbed seagrass bed. Mar. Biol.
98:447–455, based on
estimates of daily bite counts and bite size.
d
Based on 6,600,000 ha Thalassia
in the Caribbean (from Jackson, J.B.C. 1997. Reefs since Columbus. Coral Reefs
16:S23–S33) and turtle size = 50 kg.
e
216 kg DM • ha –1
• year –1
. (Recalculated from Williams, S.L. 1988. Thalassia testudinum
productivity and grazing by green turtles in a highly disturbed seagrass
bed. Mar. Biol.
98:447–455, Table 4. )
f
3,285 kg DM • ha –1
• year –1
. (From Zieman, J.C., R.L. Iverson, and J.C. Ogden. 1984. Herbivory effects on Thalassia testudinum
leaf growth and nitrogen content.
Marine Ecology Progress Series 15:151–158.)
1123 book.book Page 266 Monday, November 11, 2002 11:11 AM