Frugivory and Seed Dispersal

Consumption of fleshy fruits by frugivorous animals, which then disperse the seeds inside, is a key ecological process, particularly in forests. Fruit is an easy food to consume but is nutritionally dilute so specialist frugivores need adaptations for efficient location, harvest, and digestion. High dependence on fleshy fruits has evolved in many bird and mammal groups, as well as some reptiles and fish, and consumption by different animals can have widely different consequences for plant fitness. Plants can choose among frugivores by evolving physical (size, color etc.) and chemical traits that match corresponding frugivore traits, but there is little evidence for reciprocal co-evolution. Seed dispersal networks show similar characteristics to other ecological interaction networks, including great variation in how many interactions each species is involved in, a modular structure in which groups of species interact mostly with each other, and nestedness, so specialists interact mostly with generalists. Dependence of seed dispersal on vertebrates makes it vulnerable to human impacts, including hunting, and habitat clearance, fragmentation, and degradation. Larger vertebrates, which consume larger fruits and disperse more seeds longer distances, are most vulnerable and have been widely eliminated, reducing the ability of plant populations to respond to climate change.