A5 Limitations to the growth of epiphytes and the productivity of associated methanogens in neotropical moist forests [funded by DFG]
PI(s) for this project:
Limitations to the growth of epiphytes and the productivity of associated methanogens in neotropical moist forests
Epiphytes play an important role in tropical forest ecosystem processes by influencing fluxes of water, carbon and nutrients. Tank bromeliads, a common group of epiphytes, also affect atmospheric CH4 budgets by hosting active communities of methanogens. At present, the limitations to epiphyte growth and the productivity of associated methanogens are poorly understood. The present study addresses two main questions: (1) To what extent are establishment and growth of epiphytes in undisturbed montane forest limited by nutrient availability? Epiphyte growth response to fertilisation with moderate doses of N, P, and NP will be monitored in late juveniles of selected vascular species from different functional and taxonomical groups. Additionally, epiphyte propagules (angiosperms, foliose lichens) are sown experimentally to determine fertilisation effects on early establishment rates and seedling growth. (2) How do per capita and ecosystem-level CH4 emissions from bromeliad tanks change with elevation, and which factors limit the productivity of bromeliad methanogens? Data on per capita CH4 emissions and bromeliad densities are taken along an elevational gradient of 250-3000 m asl. Furthermore, limitations to methanogens (water, carbon, nutrients, temperature) will be explored through in situ greenhouse experiments.