Spatial population structure of a specialist leaf-mining moth

Area of Science:

• Ecology
• Population Biology
• Conservation Biology

Background:

• Spatial population structure significantly influences population dynamics.
• Metapopulation theory classifies populations as sources (self-sustaining) or sinks (dependent on immigration).
• Understanding these dynamics is crucial for predicting species persistence.

Purpose of the Study:

• To describe the spatial population structure of the leaf-mining moth Tischeria ekebladella on pedunculate oaks (Quercus robur).
• To model moth dispersal and relate it to oak distribution on a Finnish island.
• To investigate how local and regional processes affect moth population dynamics across varying landscapes.

Main Methods:

• Development of a spatially realistic metapopulation model based on individual moth behavior.
• Analysis of moth occurrence and colonization patterns in relation to oak tree size and density.
• Simulation of metapopulation dynamics under different landscape scenarios.

Main Results:

• Tischeria ekebladella populations on small oaks exhibited extinction-recolonization dynamics, while large oaks consistently supported the species.
• The majority of individual moths were found on large oak trees.
• Model predictions indicated that most local moth populations function as sinks, relying on immigration, with large oaks acting as critical sources.

Conclusions:

• The oak-moth system does not fit a single metapopulation type, demonstrating a mix of categories.
• Population persistence varies across the landscape, influenced by oak size and density.
• Classifying metapopulations into rigid categories is insufficient; understanding landscape-specific dynamics is key for conservation.