Agriculture Reference
In-Depth Information
These results have been confirmed by Persson (1988) who observed a strong response
of the soil fauna to the liming of a 40-year-old spruce stand in southern Sweden. Three
years after the application of lime (1.55 and earthworm numbers had
increased tenfold with no significant effect attributable to the amount of lime applied.
Finally, the overall effect of plant community change on earthworm communities
depends closely on the type of replacement vegetation and the earthworm community
that was present in the original ecosystem. Three examples are used to illustrate this
point: the establishment of pastures in Europe following the clearing of deciduous
forests, pastures established in Peruvian Amazonia following slashing and burning of
the primary forest, and pastures of African grasses and herbaceous legumes established
in a natural savanna environment in the eastern plains of Colombia (Table IV. 14).
Species richness is low in the largely forest-derived earthworm communities of
European pastures although it still remains in the upper range of values normally found
in forests. In Amazonia, all the species indigenous to the forest disappeared after clearing
and a new community of purely exotic species was established. Earthworm populations
had twice the biomasses of those of the primary forest, due to colonisation by the highly
vagile pantropical endogeic species
Pontoscolex corethrurus.
In contrast, in the Colombia
savannas, conversion of native savanna into pastures dominated by African grasses
and herbaceous legumes lead to substantial increases in the populations of the existing
earthworm communities.
