Host range as an axis of niche partitioning in the plant-feeding nematode community of banana agroecosystems

The stability and positive functions (such as pest regulation) of intensively managed agroecosystems can be enhanced by increasing biodiversity (in particular, by introducing cover plants or associated crops). Therefore, understanding modes of interspecific interactions among the phytophagous species, such as coexistence via host-plant partitioning, may allow manipulation of the balance between pest and nonpest species. In the present study, we tested the hypothesis that a community of six plant-feeding nematode species in banana agroecosystems is structured by host plants. This was done using extensive data on the abundance of the different nematodes species on banana and associated weeds in Martinique. Because the purpose of this study was to focus on host-plant range, we eliminated the effects of temperature, rainfall, and soil type using a partial canonical correspondence analysis. Host plants in banana agroecosystems have a marked influence on the plant-feeding nematode community structure. Host plants allow niche partitioning between some but not all pairs of species. The most evident pattern is the niche partitioning among the three nematodes considered long established in Martinique. For pairs of species showing no host-plant niche partitioning, additional information regarding the colonisation and population dynamics over time both at the root and agroecosystem scale would allow better understanding of the equilibrium among species of the plant-feeding nematode community. For management purposes, the modification of abundance of some host plants, which could be used as cover plants in the field, could change the balance among nematode species. (Résumé d'auteur