The solution of goose damage problems in The Netherlands, with special reference to compensation schemes

In The Netherlands farmers can apply to the Game Fund in order to receive compensatory payments in the event of damage by wild mammals and birds. In recent years the amount of money paid annually has increased up to £758,000. Although adequate as a basic measure to offset the losses suffered, the large increase in the total amount involved leads to questions about the accuracy of the estimated damage in relation to the actual crop reduction.
In certain areas in The Netherlands research is aimed at minimizing damage by altering land use in agricultural areas and restoring original habitats for wintering geese. This is a new approach for solving the apparent future conflict between a further increase of the amount of money paid to refund the damage claimed and the aims of conservation.     

Impact of gaseous nitrogen deposition on plant functioning

Dry deposition of NH₃ and NO_x (NO and NO₂) can affect plant metabolism at the cellular and whole-plant level. Gaseous pollutants enter the plant mainly through the stomata, and once in the apoplast NH₃ dissolves to form NH₄⁺, whereas NO₂ dissolves to form NO₃⁻ and NO₂⁻. The latter compound can also be formed after exposure to NO. There is evidence that NH₃-N and NO_x-N can be reversibly stored in the apoplast. Temporary storage might affect processes such as absorption rate, assimilation and re-emission. Once formed, NO₃⁻ and NO₂⁻ can be reduced, and NH₄⁺ can be assimilated via the normal enzymatic pathways, nitrate reductase (NR), nitrite reductase and the glutamine synthetase/glutamate synthase (GS/GOGAT) cycle. Fumigation with low concentrations of atmospheric NH₃ increases in vitro glutamine synthetase activity, but whether this involves both or only one of the GS isoforms is still an open question. There seems to be no correlation between fumigation with low concentrations of NH₃ and in vitro GDH activity. The contribution of atmospheric NH₃ and NO₂ deposition to the N budget of the whole plant has been calculated for various atmospheric pollutant concentrations and relative growth rates ( RGRs ). It is concluded that at current ambient atmospheric N concentrations the direct impact of gaseous N uptake by foliage on plant growth is generally small.     

Nitrogen on microbial and global scales

Several temporal and spatial scales have been considered during the Symposium, and the presentations by Wallenda & Kottke (1998) and by Norby (1998) represent two extreme points in a wide range. They both deal with short and long-term impacts on the local as well as the global scale. I present here a few additional thoughts, and a subject that both papers have touched only slightly will be expanded: the differential impact of different forms of nitrogen deposition.