Aboveground-belowground linkages and soil biodiversity across a latitudinal gradient in Antarctica
The Antarctic Peninsula is experiencing rapid environmental changes, making it susceptible to alterations in species diversity and distribution, both above- and belowground. However, we lack a firm understanding of soil biodiversity, including linkages with the aboveground community and relationships to changing environmental parameters. This strongly limits our ability to predict the consequences of environmental change for soil communities. To begin determining the nature and strength of aboveground-belowground linkages in influencing soil community biogeography and diversity over a latitudinal gradient of environmental and climatic conditions, we sampled the soil microbial (bacteria, archaea, fungi) and invertebrate communities at five sites along the Peninsula, beneath key aboveground habitats (moss, grass, lichen, algae, and bare soil). Soil chemistry and climate conditions were measured to determine the relationship between soil communities and physical and chemical properties.
Results to date have been obtained for a latitudinal gradient between Adelaide Island (~68°S) and Ellsworth Land (~75°S). Soils at the northern end of the sampled region are more acidic (pH 3-5) and higher in organic matter content (20-85%), as compared to the neutral (pH 6-7), low organic matter content (1-3%) soils found farther south. This reflects the peat-like nature of the soils in maritime Antarctica as compared to the sandy soils of continental Antarctica to the south. More extensive vegetation cover in the northern end of the sampled region led to greater richness and abundances of soil invertebrates (reaching 10’s to 100’s of thousands of individuals per m2, as opposed to mere thousands farther south), and there appears to be a switch in community structure between the northern and far southern regions, with different species represented. Within individual sites, the type of vegetation cover has a relatively minor impact on invertebrates, with mixed-composition soil crusts favoring greater invertebrate abundance than monocultures of individual cover types. Microbial community data are forthcoming.