Inferring biodiversity resilience using novel genetic approaches to analyze arthropod communities along the Hawaiian Island Chronosequence

• Applicant: Dr. Sven Weber
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 551085661

The global biodiversity crisis represents a significant challenge for humanity. Earth's ecosystems are not static but are composed of constantly changing networks of species interactions that respond to ecological and evolutionary forces. Understanding these dynamics is crucial for grasping how biological communities change and what underpins their resilience to stressors. Up to this point, various methods have been employed to study resilience, focusing on species diversity and the interactions among species based on co-occurrence networks. However, the latest findings and advances in molecular ecology suggest that most studies are based on occasional interaction. In my proposal "Inferring biodiversity resilience using novel genetic approaches to analyze arthropod communities along the Hawaiian Island Chronosequence" I outline a research project focusing on the assessment of biodiversity and ecological dynamics within the Hawaiian archipelago over two different time scales. The first-time scale is an evolutionary timescale over millions of years, across the substrate age of the Hawaiian Islands, while the second timescale of 10 years is considered an ecological time scale. The study will employ a combination of environmental DANN (eDNA), gut content analyses, and traditionally sampled arthropod communities to compare shifts in arthropod species composition changes and interaction changes based on true interactions. Using the latest trends and methodologies in the field of eDNA I will create molecular data for plant-arthropod-interactions and prey-predator-interaction of the Hawaiian montane wet forests to decipher the project's main hypotheses: 1. The diversity of native arthropod species relative to non-native species will be highest on the oldest islands, while the diversity of non-native species will be highest on the youngest islands (evolutionary timescale). 2. Interaction networks of arthropod communities show higher specialization and modularity following the substrate age gradient of the Hawaiian archipelago (evolutionary timescale). 3. Younger communities are dominated naturally by colonization and will therefore show greater turnover over ecological time scales (ecological timescale). These hypotheses are based on the premise that older islands have had more time for species to disperse, establish, and evolve, leading to a richer and more complex community structure. Conversely, younger islands are expected to show a higher diversity of non-native species due to lower diversity of native species and hence lower biotic resistance to invasion. Additionally, older communities are expected to exhibit increased specialization in food web interactions, while younger communities are expected to be more dynamic and show greater ecological turnover. The findings of this study would be a new addition to the field of network biology, while also answering open questions in ecology, evolution, and conservation.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Professorin Rosemary Gillespie, Ph.D.