Niche partitioning based on soil type and climate at the landscape scale in a community of plant-feeding nematodes

Abstract

Understanding how environmental factors structure communities is important in conservation biology and ecosystem management. The aim of this study was to test the hypothesis that a plant-feeding nematode community composed of six species is structured by soil type and climate at the landscape scale, and that niche partitioning via these factors is consistent with the coexistence of the species. Martinique has an impressive diversity of abiotic factors (climate and soil type) over a relatively small land area, which facilitates the study of how soil type and climate affect the nematode community.We conducted this study by building an extensive data set containing the abundance of each nematode species on banana (3708 samples and 5,673,705 nematodes) in a wide range of sites in Martinique. The data set also contained environmental data (soil, climate) and plantation age. We analyzed the response of each nematode species to climate and soil type with a generalized linear model in order to understand whether niche partitioning of factors could contribute to the coexistence of the nematode species.Temperature, rainfall, soil type, and plantation age significantly affected the abundance of the six nematode species. While some pairs of species shared the same environmental niches, other showed clear niche partitioning along climatic axes. The two dominant species, Radopholus similis and Helicotylenchus multicinctus, have similar convergent ecological niches regarding climate, soil type, plantation age, and host range. These two species, which often co-occur, probably have different resources at the root scale. Soil type and climate structure plant-feeding nematode species community at the island scale. Further studies need to evaluate coexistence at the root scale among dominant species.