Response of soil mite abundance and diversity to a monospecific timber Tectona grandis plantation in Ivory Coast

Abstract

This study aims to assess the impact of monospecific Tectona grandis forest plantation on the soil mite abundance and diversity. To achieve these objectives, two sites situated in Ivory Coast were investigated. The first, a primary forest was characterized by a very weak human activities whereas the second, a teak plantation was characterized by a high disturbance performed during the planting. After extracting, sorted and description, 116 mite species were described in the two sites. Mite densities were lower in teak plantation and also higher in the litter and decreased to the depth in both sites. Species richness recorded in teak plantation (52 species) was significantly lower compared to primary forest (98 species). The same trend was observed for Oribatida but not for Gamasida. The lower Oribatida (5 vs. 17) and higher Oribatida (24 vs. 41) were recorded respectively in teak plantation and primary forest. Mite Shannon index and evenness were significantly different between sites. High Jaccard index values and the appearance of exclusive species in both habitats showed that the sites are very distinct. Total number of species recorded corresponded to 58%–63% of the total number of species estimated by ACE and Chao 1&2 estimators, indicating that the sampling effort was not sufficient. Mite abundance and diversity varied depending on the characteristics of habitats. Chemical element (Corg, Ctot, Ntot, and SOM) values were lower in teak plantation (disturbed habitat) and significantly different to primary forest in the topsoil. Apart from litter height, soil depth, pH and C/N ratio, others variables were strongly correlated to mite abundance and diversity.