Nematode communities of Byers Peninsula, Livingston Island, maritime Antarctica

The nematode communities of Antarctica are considered simple. The few species present are well adapted to the harsh conditions and often endemic to Antarctica. Knowledge of Antarctic terrestrial ecosystems is increasing rapidly, but nematode communities remain to be explored in large parts of Antarctica. In soil samples collected at Byers Peninsula (Antarctic Specially Protected Area No. 126), Livingston Island we recorded 37 nematode taxa but samples showed great variation in richness and abundance. Nematode richness decreased with increasing soil pH, whereas total abundances, and the abundance of several trophic groups, were greatest at intermediate pH (around 6.5-7). Moreover, the community composition was mainly related to pH and less so to soil moisture. Trophic group, and total nematode, rotifer and tardigrade, abundances were generally positively correlated. Byers Peninsula is thus, by maritime Antarctic standards, a nematode biodiversity hotspot, and the presence of several previously unrecorded genera indicates that nematode species richness in maritime Antarctica is probably underestimated. Our results indicate that abiotic factors influence nematode communities with little evidence for biotic interactions. The unexplained heterogeneity in community composition is probably related to variation in microclimate, vegetation, topography and unmeasured soil properties, but may also be contributed to by biological processes.