How can migrating birds help cold-adapted plants colonize tropical mountains?

In tropical regions, the vast expanse of lowland forest acts as a significant barrier to the migration of cold-adapted biota, isolating high-altitude mountain peaks from other temperate environments. Despite this isolation, colonization of these equatorial summits by cold-adapted plants has occurred, with birds serving as key agents of dispersal.1

Because birds are highly mobile and capable of traversing geographical barriers, they can travel between distant, isolated mountain ranges. Migrating birds may act as vectors for the seeds of cold-adapted plants, transporting them to high-altitude tropical peaks that lack relatives in the surrounding lowlands. This process allows plant species that are otherwise restricted to cooler climates to establish populations in the unique, island-like environments of tropical mountaintops.12