La planta exótica kalanchoe daigremontiana incrementa el reservorio y flujo de carbono en el suelo

Invasion by exotic plants generates changes in soil nutrients reservoirs and dynamics, which can accelerate the invasion process and alter the function of ecosystems. Kalanchoe daigremontiana is an exotic plant native of Madagascar that invades semi-arid zones in Northern Venezuela. The aim of the present work was to evaluate the changes generated by the invasion of K. daigremontiana upon the soil carbon reservoir and fluxes. Random samples were collected from invaded soils and non-invaded soils adjacent to the front of invasion. From each sample, determinations were made of physical soil properties such as texture and moisture content, of carbon reservoirs such as organic carbon and carbon from the microbial biomass, and of soil respiration as a measure of metabolic activity of microorganisms, as well as the flow of carbon to the atmosphere. Results indicate that the invasion by K. daigremontiana can modify in the short term the carbon cycle in the soil. The invasion increases carbon content, total metabolic activity of the soil microbiota and soil-atmosphere carbon flux, due to the increment in the amount of energy available (organic matter) for soil microorganisms and to better conditions (moisture) for their activity. These results show an additional mechanism through which K. daigremontiana can become a successful invader and alter the functioning of the receptor ecosystem.