The Nematode Fauna of the Regenerated Woodland and Grassland of Broadbalk Wilderness

Abstract

Of the 81 nematode species found in the soil of the regenerated woodland and the ungrazed grassland of Broadbalk Wilderness, 57 were common to both. The populations in the two sites contained different species of Tylenchida and different proportions of plant and bacterial feeders. The horizontal distribution of Helicotylenchus and Rotylenchus species differed in the two sites. The population of H. vulgaris in the grassland had one peak in Spring and another in Summer. R. pumilus also had a spring peak earlier than H. vulgaris but had no pronounced Summer peak. In the woodland and grassland, where vegetation cover was complete, nematodes were most abundant in the surface soil and the density decreased with depth, except during August. In the Broadbalk Wheat crop, where the soil was only partly covered, most nematodes occurred at 6-8 cm and few at 0-2 cm. During November 1963, February, May and August 1964, most R. pumilus were at 0-2 cm in the grassland, but most H. vulgaris were at 4-8 cm in August and at 8-10 cm in February, with no pronounced population peak in May or November. The vertical distribution of neither species was related to amount of moisture or root in the soil; and neither species was observed to migrate vertically.