Context-dependent plant-bird interactions shape polychory across the antagonism-mutualism continuum

Area of Science:

• Ecology
• Zoology
• Botany

Background:

• Animal-plant interactions range from seed predation to dispersal, influencing ecological dynamics.
• The continuum of antagonism-mutualism in these interactions is not fully understood.

Purpose of the Study:

• To investigate the complex outcomes of bird-plant interactions, focusing on seed dispersal and predation.
• To identify the factors shaping interaction outcomes and dispersal mechanisms.

Main Methods:

• Systematic monitoring of 6,012 foraging visits by 25 bird species across 40 plant species over a year.
• Analysis of interaction outcomes (seed predation, fruit defleshing, seed dispersal) and dispersal mechanisms (endozoochory, stomatochory, epizoochory).

Main Results:

• Interaction outcomes and dispersal mechanisms were influenced by fruit traits, bird feeding strategies, and fruit-to-bird size ratios.
• Most bird species exhibited multiple interaction outcomes; seed predators often served as effective non-endozoochorous dispersers.
• Polychory (multiple dispersal methods) occurred in 50% of plant species, with 47.5% relying on overlooked stomatochory or epizoochory.

Conclusions:

• Birds act as dynamic, context-dependent agents of seed fate, combining multiple interaction outcomes.
• Seed dispersal ecology requires integrating trait-based and behavioral perspectives to understand complex bird-plant interactions.