Due to their economic importance being unknown in most crops, apart from other pests, plant-parasitic nematodes have been frequently neglected in the agroecosystems, assuming 'status' only when their population is very high, causing accentuated damages which leads to significant yield losses. Nevertheless, only 10% of the nematode universe is parasites causing damages to plants; 25% are free-living forms including bacterivorous, fungivorous, omnivorous or predators according to their feeding habits. The relationship between the nematode population level and the damage level for each crop is unknown. Therefore, pesticides are considered the best control option for farmers, but the indiscriminate use could lead to the instability of soil communities resulting in environmental risk. For the risk evaluation, originated from chemical substances, impacts on different types of soil management, as well as disturbances suffered by the soil, several toxicity tests with nematodes have been carried out and there is an increased demand in their use in highly developed countries. The analysis of the soil nematode communities in some ecosystems, according to their feeding habits and maturity index proved to be a good indicator to the damages caused by pollutants or ecological disturbances. In this review, data that demonstrate that these organisms can be used in a satisfactory way in studies of sustainability of ecosystems, due to their abundance, diversity and responses to the toxicity and environmental disturbances, are presented.
bacterivorous; fungivorous; omnivorous; nematode community; abundance; biomass