Abstracts (first author)
Biodiversity affects phenotypic plasticity in subtropical trees
Plasticity allows plants to respond to environmental changes through changing phenotypes during their lifetime and this may be especially important for long lived species such as trees. Biodiversity loss could affect the expression of phenotypic plasticity of growth related traits and this could in turn affect the ability of species to respond to environmental changes. It is therefore important to understand what effects biodiversity has on phenotypic plasticity and we might expect two possible outcomes: firstly, more species rich communities might be more structurally diverse forcing plants to also express higher trait variation in diverse communities. Alternatively in low diversity communities niche space for individual species might be larger allowing niche expansion through an increased variation in growth traits between individuals. To test these ideas we studied plasticity of trees in a large biodiversity experiment in China "BEF China". In this experiment large scale experimental communities were established on an area of 24ha. A total of 60, 000 seed family replicates of thirteen subtropical tree species were grown in plots comprising 1, 2, 4, 8, 16 and 24 species. We measured total height, crown height, crown volume, stem diameter and herbivore damage in twelve species, across the diversity gradient. We calculated plasticity as the variance in growth traits between individuals of the same seed family within a plot. Our results show a significant and consistent decrease of growth trait variation with increasing species diversity. They indicate that biodiversity can influence the expression of phenotypic plasticity and they support the hypothesis that reduced interspecific competition causes increased trait variation. Trees in low diversity communities therefore seem to expand their niches by increasing trait variation.