During the period 1990-1993, the Acadia Centre for Estuarine Research carried out an intensive field study at a number of sites in the Tobeatic Wildlife Management Area of southwestern Nova Scotia to determine the feasibility of using artificial fertilization for enhancement of waterfowl production in acidified and oligotrophic wetlands. The primary objectives of the study were to determine the effectiveness of controlled artificial fertilization in stimulating production processes and to evaluate the overall environmental impact, particularly on adjacent systems, of fertilizer addition. The results of that study (Brylinsky 1993) indicated that, although these systems respond well to the addition of artificial fertilizers in terms of increased primary and secondary production, the length of time production was enhanced varied considerably among sites. Within one or two weeks after fertilization, phytoplankton levels at the fertilized sites rose to more than an order of magnitude above pre-fertilization levels. Phytoplankton levels in the early spring of the second year, however, had decreased substantially, particularly in those sites characterized by high flushing rates and a thermally unstratified water column. Zooplankton biomass showed little change during the year of fertilization, but increased during the second year after fertilization. Those organisms having longer generation times, such as emergent insects and benthic invertebrates, showed little response to fertilization during the two years after fertilization.

These results suggest that the effect of artificial fertilization is relatively short-lived, particularly with respect to phytoplankton productivity. In order for artificial fertilization to be considered a cost effective management technique for enhancing waterfowl productivity, management agencies maintain that fertilizer addition should not be required more than once every four or five years. Thus the increase in productivity brought about by one-time fertilization should last a minimum of three to four years. It was therefore considered desirable to continue monitoring productivity levels for at least one more year in order to provide a more complete evaluation of artificial fertilization as a management technique.