COS 143-10
Complementarity effect of biodiversity on ecosystem functioning emerged from neighborhood competition among plants
The mass extinction of species underway has been considered a critical threat on the benefit and sustainability of human being, that’s due to the fact that diversity of global organisms plays an important role in the provision of products and services to the mankind. During the last two decades, numerous studies have been devoted to explore the relationship between biodiversity and ecosystem functioning (BEF). Although there are some exceptions, most studies reach a consensus that biodiversity generally has a significant positive effect on the multi-aspects of ecosystem functioning, such as productivity, decomposition and nutrition retention. The impact of biodiversity on ecosystem functioning is attributed to two categorized underlying mechanisms, selection effect and complementarity effect. The post hoc statistical method, additive partition, has been generally used to evaluate the magnitude and contribution of these two different effects on the relationship between biodiversity and ecosystem functioning. We used the zone of influence model to explore the selection effect and complementarity effect of neighborhood competition on the variation of diversity-productivity relationships with community succession.
Results/Conclusions
Positive selection effect emerged at the early stage of succession due to the domination of species with higher initial growth rate. With the ongoing of succession, selection effect became negative since the rank of monoculture’s biomass reversed. Selection effect became positive again and increase greatly at the late stage of succession for the community with size symmetric competition, that’s because species with lower initial growth rate gradually dominated the community. Although either niche differentiation or facilitation was included in our model, complementarity effect emerged, especially for the community with size symmetric competition which had strong negative complementarity effect at the late stage of succession. The magnitude of this negative complementarity effect is so large that it overwhelmed the positive selection effect and finally resulted in the negative diversity-productivity relationships. Since neighborhood competition is a general species interaction mechanism among plants, our result proposed the most plausible explanation for the emergence of negative complementarity effect within plant community. Because specific biological mechanism such as neighborhood competition can cause both the selection and complementarity effect, more theoretical and empirical works are urgently needed to untangle the potential relationships between selection and complementarity effect with the underlying specific species interaction mechanisms.