Cycas-circinalis-cas.. - Cycad Specialist Group
Cycas-circinalis-cas.. - Cycad Specialist Group Cycas-circinalis-cas.. - Cycad Specialist Group
Fig. 6. Population structure of C. circinalis subject to different types of harvest. a) Fruit harvest only, N= 63; b) Fruit and leaf harvest, N=33; c) Fruit, leaf and stem harvest, N=69. Population structure is dependent on harvest type (χ 2 = 25.02 p < 0.001) Proportion of individuals 0.5 0.4 0.3 0.2 0.1 0 0.5 0.4 0.3 0.2 0.1 0 0.5 0.3 0.1 -0.1 Seedlings >50 50-100 100-150 150-200 200+ Seedlings >50 50-100 100-150 150-200 200+ Seedlings >50 50-100 100-150 150-200 200+ Height (cm ) 18
There was a very strong positive correlation between number of leaf scars and C. circinalis height (Fig. 7). This allowed us to estimate cycad age based on their height. Given that each individual produces two whorls of leaves per year, the height class categories in Fig. 4 can be converted to approximate ages, illustrated in Table 5. Fig. 7. Relationship between height and number of leaf scars for C. circinalis. N=34, p < 0.001 No. of leaf scars 350 300 250 200 150 100 50 0 y = 0.7832x - 5.9523 R 2 = 0.9505 0 100 200 300 400 Height (cm) Table 5. Conversion of height classes to age classes based on estimates from number of leaf scars. Height class category (cm) Estimated Age Class (years) Seedlings (no stem) < 50 (non reproductive) 75 These results suggest that cycads of about 15 years old and more are heavily harvested for their leaves. The data also indicate that C. circinalis individuals begin to reproduce at approximately 17 years of age. The biggest individual found measured 330 cm high, and is estimated to be 146 years old. 19
- Page 1 and 2: Harvest, trade, and conservation of
- Page 3 and 4: 3) Assess the impacts of harvest on
- Page 5 and 6: Fig. 1. Biophysical zones of the Ni
- Page 7 and 8: Fig 2. Location of C. circinalis st
- Page 9 and 10: harvest , ratio of female: male ind
- Page 11 and 12: Table 3 Cont’d. Pith Yes Yes Medi
- Page 13 and 14: Fig. 3. Cycas Circinalis L. a) adul
- Page 15 and 16: In total, 150 Cycas circinalis indi
- Page 17: Fig. 5. Relationship between C. cir
- Page 21 and 22: 5. Discussion 5.1 Traditional fruit
- Page 23 and 24: populations would be to push for a
- Page 25 and 26: Nantel, P., Gagnon, D. & Nault, A.
- Page 27: Can you predict productivity and wh
Fig. 6. Population structure of C. <strong>circinalis</strong> subject to different types of harvest.<br />
a) Fruit harvest only, N= 63; b) Fruit and leaf harvest, N=33; c) Fruit, leaf and stem<br />
harvest, N=69. Population structure is dependent on harvest type (χ 2 = 25.02 p < 0.001)<br />
Proportion of<br />
individuals<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.5<br />
0.3<br />
0.1<br />
-0.1<br />
Seedlings >50 50-100 100-150 150-200 200+<br />
Seedlings >50 50-100 100-150 150-200 200+<br />
Seedlings >50 50-100 100-150 150-200 200+<br />
Height (cm )<br />
18
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