Fruit availability for migratory birds: a GIS approach.

Area of Science:

• Ecology
• Ornithology
• Geographic Information Systems (GIS)

Background:

• Bird migration patterns are influenced by food availability, but large-scale spatial data are lacking.
• Understanding en route food resources is crucial for migration success, timing, and patterns.
• Previous studies lacked spatial models for terrain-based food availability.

Purpose of the Study:

• To develop a GIS-database approach for mapping fruit availability across landscapes.
• To analyze the relationship between fruit availability and bird migration in the SE Alps.
• To provide spatial data for ecological studies on migratory birds and other frugivores.

Main Methods:

• Combined spatial and non-spatial ecological data using a GIS-database.
• Created a database of 52 wild, berry-producing plants, including their fruiting periods.
• Modeled plant species presence and coverage using Gaussian Kernel geo-statistics, validated with field data (>80% accuracy).

Main Results:

• Generated maps of fruit availability over time in the SE Alps.
• Demonstrated that peak fruit availability in September-October coincides with peak berry-eating bird captures.
• Validated the Gaussian Kernel model's effectiveness for mapping plant species distribution.

Conclusions:

• The GIS-database approach successfully mapped spatiotemporal fruit availability.
• Findings highlight the importance of fruit resources for migratory birds in the SE Alps.
• The created maps serve as a valuable tool for future research on stopover ecology and frugivore spatial dynamics.