B3 Trait-dependent effects of biotic and abiotic filters on plant regeneration [funded by DFG]
PI(s) for this project:
Climate and land-use change cause biodiversity loss in tropical forests and lead to disruptions in important ecosystem functions, such as forest regeneration. The regeneration cycle of plants comprises the transitions from seeds to seedlings to adult plants and is influenced by several ecological processes, such as mutualistic and antagonistic plant-animal interactions. Plant functional traits have important implications for these processes. For instance, small-seeded plants are dispersed by frugivorous birds with small and large gape width, whereas large-seeded plants depend exclusively on frugivores with large gape width. Plant traits also directly impact seedling establishment because large-seeded plants generally have a higher probability to establish than small-seeded plants. Understanding the diversity of functional traits in plant communities is therefore essential to understand responses of plant communities to global change and to predict effects on ecosystem functions. In this project, we seek to investigate how climate and land-use change affect plant regeneration in a diverse tropical montane rainforest in Southern Ecuador. Specifically, we aim at studying how plant functional traits, such as plant successional status and seed size, affect different processes of plant regeneration and how biotic and abiotic filters limit plant regeneration at different elevations and in forests, pastures and pine plantations. In the first work package, we will describe trait spaces of fleshy-fruited plants to identify relevant plant response traits (e.g., successional status) to elevation and habitat modification and important effect traits (e.g., seed size) for plant regeneration. In the second work package, we seek to compare seed-dispersal efficiency of different-sized seeds in the forest and in the human-modified habitats at different elevations. In the third work package, we will conduct seed-sowing experiments to disentangle the relevance of biotic (fungal pathogens, herbivory) versus abiotic filters (e.g., leaf area index, soil parameters) for the establishment of plant species that differ in species traits. In the fourth work package, we will quantify seedling establishment and survival under natural conditions to validate the data derived from the establishment experiment. Overall, these studies will elucidate the ecological processes that limit the establishment of plants that differ in species traits under varying biotic and abiotic conditions. The project will contribute to the statistical synthesis by identifying important response and effect traits of the plant community and will provide essential data to parameterize the biotic and abiotic components of the plant establishment module of the dynamic vegetation model (LSMBio).