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