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Work Package 1

WORK PACKAGE 1. Theoretical basis.

Aim: To provide a solid theoretical understanding of the importance of megafauna in ecosystems. Notably, it will focus on:

  1. Developing theory for the role of functional (incl. trophic) diversity for megafauna effects on ecosystems
  2. Predicting megafauna community assembly and ecosystem consequences from simple species’ traits, local environmental conditions and landscape setting (to be able to guide design of restored megafauna, which may involve novel species combinations, e.g., due to extinctions of native species)

Background: To develop such theory, we will combine allometric scaling theory, network and food web theory (size-based food web structure and food web metacommunities), mechanistic modelling of animal-mediated effects on ecosystem structure and processes, and meta-ecosystem theory (spatial flows of organisms, energy and nutrients).

Methodology: Theory development via mathematical analyses and testing on empirical data, from the literature and WP 2-3. As a key approach, we will develop a mechanistic model of trophic interactions with explicit representation of metabolism, ecological interactions and demography. A breakthrough in this direction was accomplished recently with the first global process-based ecosystem model, the Madingley Model. This type of global model offers new avenues to study impacts of spatial dynamics, nutrient flows and range shifts, by linking different ecosystems and processes. The model requires knowledge of the structure of the regional food web, which we will estimate using a niche model for food web structure. We will use scaling theory for predator-prey relationships to infer its parameters and consumer-resource theory to derive interaction coefficients from scaling relationships. We will use the model to explore ecosystem effects such as:

  1. How much megafauna is controlling primary and secondary productivity?
  2. Can megafauna drive ecosystem shifts from forest to grasslands?
  3. How do climate and megafauna interact to affect ecosystem processes?