Ecological indexes of arthropods on Sapindus saponaria plants with dehydrated sewage sludge as fertilizer

Abstract

Plant species, monitoring measures, and alternative fertilization with sewage sludge accelerate recovering of degraded areas. The objective of this study was to evaluate the numbers of leaves/branch and branches/plant of Sapindus saponaria L., the ground cover by this plant and the ecological indexes of abundance, diversity, and species richness of insects and spiders, and of their interactions, during 24 months on trees grown in a degraded area with or without dehydrated sewage sludge as fertilizer. The metrics of plant, soil cover, and arthropods were higher on the S. saponaria plants fertilized with dehydrated sewage sludge. The abundance of chewing insects, tending ants, and spiders was greater on larger S. saponaria tree crown. The abundance of these last groups of organisms associated, negatively, with that of Coleoptera, but those of ants reduced that of the predators. The ecological indexes of arthropods on S. saponaria plants shows the suitability of this plant for recovering programs of degraded areas and the use of dehydrated sewage sludge as fertilizer increased these indices and the possibility of using insects and spiders on the crown of this plant as bioindicators.