“…Harris, 1980;Giddings & Franco, 1985;Portier, 1985) Gregory, 1984;Muirhead-Thomson, 1987). Solomon et al, 1980;Dejoux, 1982;Lewis, 1986;Munawar & Munawar, 1987) and, finally, the manipulation of natural systems themselves (e.g. Arthur et al, 1983;Kownacki et al, 1985;Yasuno et al, 1985;Zischke & Arthur, 1987) and ponds (e.g.…”