Taxonomy and Ecology Of Inland Sand Dune ... - Mycorrhizae

20Sheppard, 1976; Foster and Nicolson,1981).VAM fungi are important for buildingand maintaining the structure of sanddunes and for plant stabilization. Aconsiderable amount of hyphalconnections of fungal mycelium wasfound in the top 1-20 cm of mobile sandin Cooloola (Queensland), Australia(Jehne and Thompson, 1981). VAMfungi bind loose sand grains into largeraggregates with their sticky hyphae andthus limit sand dune loss. Foster andNicolson (1981) found that 1.5% of theaggregate sand grains reach a diameterof 2 mm in Scotland dunes. The 2-mmsand grain aggregations may be as highas 9% in Lake Huron dunes (Koske etal., 1975). Migration of sand grains bywind can be significantly reduced bysand grain aggregations. The aggregatesalso can improve soil structure bytrapping organic matter, limiting waterloss, and by becoming sites of microbialactivity.All major genera (Acaulospora,Entrophospora,Gigaspora,Scutellospora, Sclerocystis, and Glomus)of VAM fungi have been found in arid,semi-arid, and sand dune soils aroundthe globe (Khan, 1974; El-Giahmi et al.,1976; Redhead, 1977; Diem et al., 1981;Schwab and Reeves, 1981; Bloss, 1985;Halvorson and Koske, 1988; McGee,1989). Of the 148 species of VAMfungi, 31 species were first reportedfrom sand dunes (Schenck and Pérez,1990). The 31 species are in threegenera: Glomus (14 species),Scutellospora (12 species), andAcaulospora (5 species).VAM inoculum density varies from siteto site and decreases with soil depth(Sutton and Barron, 1972; Miller, 1979;Reeves et al., 1979; Buchholz andMotto, 1981; Schwab and Reeves, 1981;Allen et al., 1984; Zajicek et al., 1986;Koide and Mooney,1987). The distribution of VAM fungalspecies appears to be more closelyrelated to host plant, soil structure, andenvironmental conditions than to thecompetition by other VAM fungalspecies (Koske, 1981a).All these studies involved maritime sanddunes, and they were limited to the studyof the percentage colonization in sand