Nematode community structure and functional guilds differ in tea fields and tropical forest

Abstract

Agricultural intensification that results in conversion of forests into crop fields affects soil biodiversity including nematodes which contribute to ecosystem services and play a key role in maintenance of soil health. The nematode soil food web and metabolic footprints of a tropical forest and surrounding tea fields in Embu, Kenya were investigated. Soil samples were collected from tea fields and forest and the nematodes were identified to the genus level. The plant-parasitic index in the tea fields was high and the abundance of nematodes in cp2 class and Ba2 functional guild were greater than those in the forest. Helicotylenchus, Rotylenchus, Telotylenchus and Malenchus occurred in higher densities in the forest which also had a significantly high predator footprint. The pH, Mn, sand, clay and silt content varied across the forest and tea fields. Nematode communities in the two land use systems were distinct based on non-metric multi-dimensional scaling ordinations. Heterocephalobus which was positively correlated to pH and Helicotylenchus, Telotylenchus, Iotonchus and Rotylenchus which had a negative association with silt contributed to the dissimilarity observed in the forest and tea fields. The findings provide an insight into the effects of land use change on nematode communities in the two systems. This study will provide baseline data that can be used to make informed decisions on tea production and land use strategies that enhance soil health.