How bird droppings can affect the vegetation composition of ombrotrophic bogs

Abstract

Ombrotrophic bogs depend on nutrient input from the atmosphere, so bird droppings may be a significant nutrient source. We studied the influx of N, P, and K by bird droppings, and the effects of this nutrient influx on the vegetation composition and development of Irish ombrotrophic bogs. Bird droppings significantly increased the influx of N, K, and particularly P. Concentrations of N, P, and K in the peat and vegetation were much higher at sites with bird droppings than at reference sites without bird droppings. Pinus sylvestris L. trees were able to grow much better at the sites with bird droppings, and growth was severely limited by P and K at the reference sites. Sites with bird droppings allowed atypical species to grow on ombrotrophic bogs. This change in vegetation composition alters the structure of the ombrotrophic vegetation locally, thereby affecting the atmospheric nutrient input and interception of precipitation.Key words: nitrogen, nutrient limitation, potassium, phosphorus, Pinus sylvestris, soil CO2 evolution, Sphagnum.