Linking species abundance and overyielding from experimental communities with niche and fitness characteristics

1) So far, the principal force shaping local plant abundance patterns remains unclear. Rarity can result from poor competitive ability or from small vegetative or generative reproduction, but also from strong self-limitation. The same mechanisms can drive species-specific overyielding, i.e. increased species productivity at high community diversity. Rare species can then benefit more (i.e. overyield to a larger extent) from growing in species-rich communities because of altered competitive hierarchies or smaller conspecific frequencies. Here we test which mechanism is the most important determinant of species rarity and of species-specific productivity across a diversity gradient ranging from one- to 60-species plots.
2) For that we measured vegetative growth, competitive ability (competitive effect), and negative frequency dependence for 49 perennial grassland species from Central Europe. We then linked these characteristics with species abundance (measured as species biomass from 60-...

1) 迄今为止，塑造本地植物多度格局的核心驱动机制仍不明朗。物种稀有性可由较弱的竞争能力、有限的营养繁殖或有性繁殖能力所致，亦可能源于强烈的自我限制作用。上述机制同样可引发物种专属超产效应（species-specific overyielding）——即在群落多样性较高时，物种种群生产力得以提升。由于竞争层级发生改变或同种个体频率更低，稀有种在物种丰富的群落中生长时，往往能获得更显著的收益（即超产程度更高）。本研究通过覆盖1至60个物种样地的多样性梯度实验，旨在明确何种机制是决定物种稀有性及物种专属生产力的关键因素。
2) 为此，我们针对中欧地区的49种多年生草原植物，测定了其营养生长性状、竞争能力（competitive effect）以及负频率依赖（negative frequency dependence）。随后我们将这些特征与物种多度（以60-……样地的物种生物量进行量化）建立关联。