Traits underlying community consequences of plant intra-specific diversity

A plant’s performance and interactions with other trophic levels are recorgnized to be contingent upon plant diversity and underlying associational dynamics, but far less is known about the plant traits driving such phenomena. We manipulated diversity in plant traits using pairs of plant and a substitutive design to elucidate the mechanisms underlying diversity effects operating at a fine spatial scale. Specifically, we measured the effects of diversity in sex (sexual monocultures vs. male and female genotypes together) and growth rate (growth rate monocultures vs. fast- and slow-growing genotypes together) on growth of the shrub Baccharis salicifolia and on above- and belowground consumers associated with this plant. We compared effects on associate abundance (# associates per plant) vs. density (# associates per kg plant biomass) to elucidate the mechanisms underlying diversity effects; effects on abundance but not density suggest diversity effects are mediated by resource abundance (...

学界已普遍认识到，植物的表现及其与其他营养级（trophic levels）的相互作用，依赖于植物多样性（plant diversity）与潜在的关联动态（associational dynamics），但目前针对驱动这类现象的植物性状（plant traits），我们的认知仍较为匮乏。本研究通过植物配对与替代设计操控植物性状的多样性，以期阐明精细空间尺度下多样性效应的内在作用机制。具体而言，我们分别检验了性别多样性（单一性型种群与雌雄基因型混合种群的对比）与生长速率多样性（单一生长速率种群与快慢生长基因型混合种群的对比）对灌木Baccharis salicifolia的生长，以及与之关联的地上、地下消费者的影响。为进一步阐明多样性效应的内在机制，我们对比分析了多样性对伴生生物丰度（每株植物的伴生生物数量）与密度（每千克植物生物量的伴生生物数量）的影响：若多样性仅影响丰度而非密度，则表明多样性效应是通过资源丰度介导的（……）