Functional role of soil fauna and vegetation on the sensitivity of carbon stocks to changes in the abiotic factors

Resumo

The accumulation of large amounts of organic crabon in peatland soils is due to low decomposition rates as a result of low temperatures, waterlogging and acidic conditions. Consequently, there is an increasing concern over the feedback response of these carbon-rich soils to global climate changes, which has resulted in most research efforts going into the effects of these abiotic drivers on carbon losses from these ecosystems. However, the influence of biotic factors is crucial to fully understand the impact of future climate warming on peatland carbon balance. Therefore, in the current project, I have performed temporal samplings and a soil incubation experiment in several peatland habitats dominated by different vegetation in order to study the effects of plant and invertebrate key-groups on the carbon dynamics of a typical upland peatland in response to variations in abiotic drivers (namely soil temperature and soil moisture conditions). The results show that field experiments and in situ approaches are essential to improve our understanding of the functional roles of soil biota under more realistic conditions. However, further long-term studies are needed to assess the possible shifts in soil organisms and plant communities under projected climate changes. Moreover, it is anticipated that the projected expansion of vascular plants will not only displace active peat forming vegetation species (mosses), but also those invertebrates that are poorly adapted to the new environment (enchytraeids and dipteral larvae). Importantly, the direct effects of abiotic factors (soil temperature and soil moisture) on biotic communities (both plants and soil organisms) determine the magnitude of carbon losses in peatland ecosystems. Consequently, projected increases in temperatures and more often drought periods, together with a rapid expansion of vascular plants and alterations in soil biota activities, will likely hamper the current ability of peatlands to store carbon.