Effects of in situ light reduction on density and growth of the seagrass Heterozostera tasmanica (Martens ex Aschers.) den Hartog in Western Port, Victoria, Australia

摘要: Abstract Neutral density screens were used to reduce the level of irradiance available an intertidal population Heterozostera tasmanica (Martens ex Aschers.) den Hartog in Western Port, Victoria, Australia. When was reduced 9 and 2% control (ambient) levels, death all leaf clusters H. resulted within 2 10 months. Reduction 35 25% levels a 25–50% decrease cluster for duration experiment (14 months). As decreased length increased (leaf at 9% twice areas) while growth rate width remained same. It is suggested that per remains same under because likelihood self-shading by surviving surface area cluster. Density more rapidly during summer than winter light levels. This response may be due increase plant's compensation point respiration temperatures. Information on lower limits vertical distribution Port Phillip Bay, Victoria together with experimental reduction data suggests requires minimum ≈ 5% survival.