Pollination Seed Predation and Seed Dispersal

I. Types and Patterns of Pollination

A. Pollinator Functional Groups

B. Measurement of Pollination

C. Spatial and Temporal Patterns of Pollination

II. Effects of Pollination

III. Types and Patterns of Seed Predation and Dispersal

A. Seed Predator and Disperser Functional Groups

B. Measurement of Seed Production and Dispersal

C. Spatial and Temporal Patterns of Seed Predation and Dispersal

IV. Effects of Seed Predation and Dispersal

V. Summary

INSECTS AFFECT PLANT REPRODUCTION AND ASSOCIATED PROCESSES in a variety of ways. Direct and indirect effects of herbivores on plant production and allocation of resources to reproduction were described in Chapter 12. Pollination, seed predation, and seed dispersal are major processes by which insects (and other animals) affect plant reproduction and distribution. Pollinators control fertilization and reproductive rates for many plant species, especially in the tropics. In fact, some plant species depend on pollinators for successful reproduction and may disappear if their pollinators become rare or extinct (Powell and Powell 1987, Steffan-Dewenter and Tscharntke 1999). Seed predators consume seeds and thereby reduce plant reproductive efficiency but often move seeds to new locations and thereby contribute to plant dispersal. Many plant species depend on seed dispersers for successful movement of seeds to new habitats and may be vulnerable to disappearance of their dispersers (O'Dowd and Hay 1980, Schupp 1988, Witmer 1991). Pollinators and seed predators play important roles in seed production, seedling recruitment, and plant demography.

Insects are the major agents of pollination, seed predation, or seed dispersal in many ecosystems (Bawa 1990, Degen and Roubik 2004, Sallabanks and Courtney 1992). For example, Momose et al. (1998b) noted that for 270 plant species in a lowland dipterocarp forest in Sarawak, Malaysia, social bees were the primary pollinators for 44%, beetles for 24%, solitary bees for 19%, and birds and bats for 6%. Pollination and seed dispersal are among the most intricate mutualisms between animals and plants and have been studied widely from the perspective of co-evolution. Nevertheless, few studies have evaluated the effects of pollinators, seed predators, and seed dispersers on ecosystem processes, despite their importance to seedling recruitment and vegetation dynamics. Different functional groups of pollinators and seed-feeders affect seedling recruitment and vegetation dynamics in different ways.

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