Terrestrial Antarctic ecosystems are some of the most nutrient poor and least developed soils in the world. Nitrogen availability appears to be an important limitation for plant growth in some of these areas. Coastal communities of birds are known to influence plant growth by carrying nutrients from the ocean onto the land. In some subantarctic plant communities most of the nitrogen used is animal-derived. However, not all plant communities get direct influence from the nutrients from animal colonies because some areas might be inaccessible to animals; therefore, other sources of nitrogen such as precipitation and wind blown material (ocean spray and guano) could positively affect plant cover. Therefore, distance of the animal colony could be an important variable determining plant productivity and cover. We analyzed the effect that distance and size of the penguin colony has on the plant cover and ecosystem respiration (ER) at several locations at the Antarctic Peninsula. We determined a vegetation cover and ecosystem carbon fluxes using 10-30 m transect at several locations of the Antarctic Peninsula. At each location we measured the distance of the closes animal colony.
Results/Conclusions
We found a positive correlation between the number of nesting pairs of penguins with the ecosystem carbon emissions (R2=0.90, p<0.05) and plant cover (R2=0.98, p<0.05), and a negative correlation with distance of the colony and carbon emissions. Additionally, areas covered with vascular plants had the highest ecosystem carbon emissions with 74.8 CO2-C (mg/m2/h). Moss areas had rates of emissions of 26.5 to 38.2 CO2-C (mg/m2/h). Carbon flux correlated better with % of moss cover than with total plant cover. Ecosystem respiration was positively correlated also with air temperature and soil temperature, suggesting that contributions to ecosystem respiration come in similar proportions from above and below ground biomass. Our results suggest, as observed in other studies, that Antarctica soils are poorly developed, and highly dependent of the nutrients brought from the ocean by the animals that breed in the coast.
