Vegetation change and nitrogen deposition in six Canadian national parks.

Köchy, M., and S. D. Wilson (1995)

Rapid vegetation changesin parks in agricultural landscapes may be partly due to increased atmospheric N deposition. To test this hypothesis, we measured atmospheric nitrogen deposition and soil N availability in six nationalparks in western Canada, three of which were in agricultural landscapesand three surrounded by natural landscapes. Deposition was continuously collected by ion-exchange resin bags on the soil surface outside the existing forest canopy and soil available N was collected by buried resin bags. Bags were replaced four times a year. N deposition was higher in parks in agricultural landscape (3.7 g m-2 yr-1) than in natural landscape (2.5 g m-2 yr-1) during the first collection period, but the difference was not significant (P = 0.06) because one park in a natural landscape also received high loads of atmospheric N, probably by long-distance transport. Soil available N was significantly higher in parks in agricultural landscapes (0.4 g m-2) than in natural landscapes (0.1 g m-2). N deposition was not related to soil N availability. Presumably, deposited N is taken up by the vegetation which may explain changes in vegetation composition observed in parks in agricultural landscape

80. Annual Meeting of the Eclogical Society of America. Snowbird, Utah (USA), 1995.
Bull. Ecol. Soc. Am. 76 Suppl. 2:145