Forums | HES 健康与环境科学

31 October 2022, 8:33 AM

Speaker: Yu Zeng (PhD student)

Date: 2022-11-2
Time:13:30-14:00pm
Room: ES354

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https://meeting.tencent.com/dm/gDNmHFPgT2Wa
Meeting ID: 593-5627-4164

Title: Urbanization and community structure: the impact of habitat transformation on competition and predation in avian assemblages.

Abstract: Ecology seeks to explain how and why species coexist, and how community assembly determines ecosystem functioning. Urbanization provides a great opportunity to answer these questions because, across transformation gradients, specialists are substituted by generalists resulting in increased functional and phylogenetic similarity. According to the niche theory, increasing similarity would enhance competition, yet mediated by habitat productivity. However, it is unclear how these bottom-to-top processes (the relationships among productivity, niche structure and competition) interact to shape top to bottom processes (predation rates). Theoretically, increasing competition and decreasing productivity would enhance predation pressure from predators to prey, which would be reinforced by low prey selectivity of generalist species. As a result, it would be expected that predation pressure would be higher in transformed habitats. Interestingly, there are studies showing that predation rate could be higher or lower across transformation gradients. A key component of this issue is the diverse methodologies employed to study this process, which might result in biases and may make difficult reaching solid conclusions. In this seminar, Yu will introduce his study on (1) how the use of live prey and plasticine models affected our estimates of predation intensity, (2) the relationship between competition and predation and (3) What are the causes driving competition and predation intensity across transformation gradient.