FOR 5207:  Reassembly of species interaction networks – Resistance, resilience and functional recovery of a rainforest ecosystem

• Subject Area: Biology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 444827997

This research unit aims at understanding the dynamics of species interaction network in order to uncover rules of network dis- and reassembly in a highly diverse tropical lowland rainforest ecosystem. We will study (1) the impacts of agricultural land use (pastures and cacao plantations) to characterize the resistance of networks against deforestation, (2) the dynamics of natural forest recovery from agriculture along a chronosequence, and (3) the contribution of re-assembled networks to the resilience of ecosystem processes against perturbation. We will compare the trajectories of predator–prey, plant–pollinator, and plant–seed disperser networks, as well as decomposition networks between mammals, dung beetles and seeds, and between dead wood, ants, termites, and beetles. Our project thus studies networks of all major ecosystem processes mediated by interspecific interactions: predation, pollination, primary and secondary seed dispersal, herbivory, decomposition, and tree seedling recruitment. The study is located in the Choco lowland forest of North-West Ecuador, an area that faces particularly high deforestation rates. We will work within and around forest reserves owned by Fundación Jocotoco, a private Ecuadorian conservation foundation. Our 62 study plots include forests recovering for different time spans from a former use as pasture or plantation (16 under agricultural use, 30 recovering forests and 16 primary forests). All subprojects will investigate a chronosequence to assess and compare the reassembly of interaction networks and trajectories of ecosystem processes. To study how such newly composed networks offer higher process rates and temporal stability, we will perform a perturbation-recruitment experiment along the chronosequence. We will quantify the effects of functional traits that are predicted to be important for network reassembly and resilience to perturbations: response traits to environmental conditions, and interaction traits as determinants of network links. Analysing the relative contribution of these traits across distinct ecological processes allows us to distil dis- and reassembly rules of forest recovery. Changes in the complexity of networks with forest recovery is predicted to trigger variation in the rates and stability of ecosystem processes. Overall, our research unit will unravel how, to what extent, and how fast a forest ecosystem can re-establish after deforestation, including the diverse species communities, complex interaction networks, and relevant ecosystem processes that characterize such forest ecosystems.

• DFG Programme: Research Units
• International Connection: Brazil, Ecuador, USA

Projects

• Cooperation with Ecuador (Applicant Blüthgen, Nico )
• Coordination Funds (Applicant Blüthgen, Nico )
• Dung decomposition and secondary seed dispersal by dung beetles (Applicants Blüthgen, Nico ;  Schmitt, Thomas )
• Dynamics of seedling recruitment and tree seedling–herbivore interactions during forest recovery (Applicants Farwig, Nina ;  Heer, Katrin ;  Unsicker, Sybille )
• Plant-pollinator interactions: Diurnal and nocturnal pollinators (Applicants Keller, Alexander ;  Leonhardt, Sara Diana )
• Predator-prey networks, defensive alkaloids (Applicants Heethoff, Michael ;  Rödel, Mark-Oliver )
• Seed dispersal by frugivorous birds, bats and rodents (Applicants Neuschulz, Eike Lena ;  Schleuning, Matthias ;  Tschapka, Marco )
• SP7: Interactions between saproxylic insects and consequences for wood decomposition (Applicants Feldhaar, Heike ;  Müller, Jörg )
• Trait-Based Theory of Network Reassembly (Applicants Dormann, Carsten ;  Drossel, Barbara )

• Spokesperson: Professor Dr. Nico Blüthgen