PLANT DIVERSITY AND ARTHROPOD COMMUNITIES - IMPLICATIONS FOR TEMPERATE AGROFORESTRY

Polyculture in crop agroecosystems has been examined in numerous studi es with the aim of reducing pest populations by increasing diversity a mong insect populations over those found in traditional monoculture. R esource concentration and enemies hypotheses predict decreased pest po pulations in more diverse plant communities. Although results have bee n mixed, insect diversity has been generally increased in polyculture over traditional monoculture. Maintaining natural insect diversity in managed forests to limit possible pest outbreaks has been the goal in forestry systems. Increased arthropod diversity with increased tree di versity has been observed, though fewer studies have been conducted in forestry compared to agriculture. Agroforestry holds promise for incr easing insect diversity and reducing pest problems because the combina tion of trees and crops provides greater niche diversity and complexit y in both time and space than does polyculture of annual crops.