Mutualistic and Competitive Systems

The simplest and most obvious positive feedback interaction between species is mutualism. Direct interspecies mutualism can result from a multitude of interactions involving dispersal, shelter, nutrient cycling, energy provision and reproduction (Boucher et al., 1982; Faegri and Van der Pijl, 1966; Heinrich and Raven, 1972; Muscatine and Porter, 1977; Whittaker, 1975; Howe, 1977; Temple, 1977). Mutualistic interactions also arise when mutualists mediate competitive or predator-prey interactions (Wright, 1973; Janzen, 1969; Addicot, 1979; Messina, 1981; Osman and Haugsness, 1981; Heithaus et al., 1980).