The Canopy Structure and Microclimate of Papyrus (Cyperus Papyrus) Swamps
1985; Wiley; Volume: 73; Issue: 2 Linguagem: Inglês
10.2307/2260488
ISSN1365-2745
AutoresMichael B. Jones, Francis M. Muthuri,
Tópico(s)Biological Control of Invasive Species
Resumo(1) Papyrus swamps at Lake Naivasha, Kenya and at Busoro, Rwanda, were investigated. The structure of the papyrus (Cyperus papyrus) canopy is described. (2) Aerial biomass was 3245 g m-2 at Naivasha, and 1384 g m-2 at Busoro while the culm densities were 12.7 m-2 and 17.9 m-2, respectively. Combined data from several sites give a linear relationship between aerial biomass and culm density but it does not follow the thinning rule (-3/2 power law). (3) Papyrus umbels on mature culms were larger at Naivasha than at Busoro and their photosynthetic tissues (rays + bracteoles) had mean surface areas per culm of 6275 cm2 and 5242 cm2, respectively. The area of photosynthetic tissue per unit ground area (umbel area index) was 7-0 at Naivasha and 8. 1 at Busoro. (4) The chlorophyll content of the photosynthetic tissue was similar to that recorded for other emergent macrophytes and light interception by the canopy was virtually complete. There was no evidence that these features of the canopy limit productivity. (5) The annual temperature cycles at the two sites were different with the Naivasha site experiencing daily mean temperatures 3 IC, and mean minimum temperatures 10 IC, lower than at Busoro. This may account for the higher biomass at Naivasha, because lower night temperatures reduce respiratory losses. (6) There were differences in the root environment at the two sites with lower conductivity, redox potential and nitrogen concentration at Busoro. This suggests that growing conditions at Busoro were 'poorer' than at Naivasha.
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