Abstract
Photosynthetic photon flux density (PPFD) at 15 cm above the ground was measured at 20 microsites in gaps and grass patches within aMiscanthus sinensis Anderss community at 10 s intervals during 5 days every month from May to September 1989.
Microsite light availability, which was characterized by daily total PPFD, sunfleck PPFD (PPFD above a threshold value of 50 or 400 μmol m−2 s−1) and the diffuse site factor, showed evident seasonal changes, with a marked reduction between June and July due to the rapid growth of the grass canopy. The monthly median value of daily total PPFD among the microsites decreased from 10.3 mol m−2 day−1 in May to 0.77 mol m−2 day−1 in September, with a reduction in the diffuse site factor from 31 to 4%. During the summer, the median value of the total time of sunflecks exceeding 50 μmol m−2 s−1 contributed 7–18% of measurement time, but the contribution of these sunflecks to daily total PPFD ranged from 29 to 59%.
There was considerable microsite variation in light availability throughout the measurement period. Rank correlation analysis revealed that some microsites, such as those in gaps, consistently received more total PPFD, more sunfleck PPFD and had a higher diffuse site factor than those in grass patches. The diffuse site factor had a linearly positive relationship with daily total PPFD and total sunfleck PPFD for the 20 microsites during the measurement period, confirming that the diffuse site factor is a useful index for microsite light availability withinM. sinensis canopies.
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References
Anderson M. C. (1964) Studies of the woodland light climate. II. Seasonal variation in the light climate.J. Ecol. 52: 643–63.
Haldocchi D. D., Hutchison B. A., Matt D. R. &McMillen T. R. (1984) Seasonal variation in the radiation regime within an oak-hickory forest.Agric. For. Meteorol. 33: 177–217.
Chazdon R. L. (1986) Light variation and carbon gain in rain forest understorey palms.J. Ecol. 74: 995–1012.
Chazdon, R. L. (1988) Sunflecks and their importance to forest understorey plants.Adv. Ecol. Res. 18: 1–63.
Chazdon R. L. &Fetcher N. (1984) Photosynthetic light environment in a lowland tropical rain forest in Costa Rica.J. Ecol. 72: 553–64.
Curtis, W. F. &Kincaid D. T. (1984) Leaf conductance responses ofViola species from sun and shade habitats.Can. J. Bot. 62: 1268–72.
Hicks D. J. &Chabot B. F. (1985) Deciduous forest. In:Physiological Ecology of North America Plant Communities (eds B. F. Chabot & H. A. Mooney) pp. 257–77. Chapman and Hall, London.
Hutchison B. A. &Matt D. R. (1976) Beam enrichment of diffuse radiation in a deciduous forest.Agric, Meteorol. 17: 93–110.
Hutchison B. A. &Matt D. R. (1977) The distribution of solar radiation within a deciduous forest.Ecol. Monogr. 47: 185–207.
Jarvis P. G. &Sandford A. P. (1986) Temperate forests. In:Photosynthesis in Contrasting Environments (eds N. R. Baker & S. P. Long) pp. 199–236. Elsevier, Amsterdam.
Monsi M. &Oshima Y. (1955) A theoretical analysis of the succession process of plant community, based upon the production of matter.Jpn. J. Bot. 15: 60–82.
Numata M. (1961) Ecology of grasslands in Japan.J. Coll. Art Sci. Chiba Univ. 3: 327–42.
Oberbauer S. F., Clark D. B., Clark D. A. &Quesada M. A. (1988) Crown light environments of samplings of two species of rain forest emergent trees.Oecologia (Berlin)75: 207–12.
Pearcy R. W. (1983) The light environment and growth of C3 and C4 tree species In the understory of a Hawaiian forest.Oecologia (Berlin)58: 19–25.
Pfitsch W. A. &Pearcy R. W. (1989) Daily carbon gain byAdenocaulon bicolor (Asteraceae), a redwood forest understory herb, in relation to its light environment.Oecologia 80: 465–70.
Reifsnyder W. E., Furnival G. M. &Horowitz J. L. (1971) Spatial and temporal distribution of solar radiation beneath forest canopies.Agric. Meteorol. 9: 21–37.
Silvertown J. W., Prince S. D. &Smith B. A. (1988) A field-portable instrument for mapping the microenvironment within grass canopies.Functional Ecol. 2: 263–8.
Sparling J. H. (1967) Assimilation rates of some woodland herbs in Ontario.Bot. Gaz. 128: 160–8.
Tang Y. H., Washitani I., Iwaki H. (1992) Effects of microsite light availability on the growth and survival of oak seedling within a grassland.Bot. Mag. Tokyo 105: in press.
Tang Y. H., Washitani I., Tsuchiya T. &Iwaki H. (1988) Fluctuation of photosynthetic photon flux density within aMiscanthus sinensis canopy.Ecol. Res. 3: 253–66.
Tang Y. H., Washitani I., Tsuchiya T. &Iwaki H. (1989) Spatial heterogeneity of photosynthetic photon flux density in the canopy ofMiscanthus sinensis.Ecol. Res. 4: 339–49.
Tang Y. H., Washitani, I., Tsuchiya T. &Iwaki H. (1990) Growth analysis ofQuercus serrata seedlings withinMiscanthus sinensis grass canopies differing in light availability.Ecol. Res. 5: 367–76.
Taylor R. J. &Pearcy R. W. (1976). Seasonal patterns of the CO2 exchange characteristics of understory plants from a deciduous forest.Can. J. Bot. 54: 1094–103.
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Tang, Y., Washitani, I. & Iwaki, H. Seasonal variations of microsite light availability within aMiscanthus sinensis canopy. Ecol. Res. 7, 97–106 (1992). https://doi.org/10.1007/BF02348488
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DOI: https://doi.org/10.1007/BF02348488