An Evaluation of Methods for Estimating the Net Aerial Primary Productivity of Estuarine Angiosperms

Abstract

SUMMARY (1) Five harvest methods (peak standing crop, and the methods of Milner and Hughes (1968), Smalley (1959), Valiela, Teal & Sass (1975), and Wiegert & Evans (1964) were used to estimate the net aerial primary production (NAPP) of angiosperm species in coastal salt marshes of eastern U.S.A. (2) Differences as great as ten-fold were found between the five methods. All methods except that of Wiegert & Evans underestimated NAPP. Wiegert & Evans' method may have overestimated NAPP. (3) The ranking of species by NAPP, which may be used as a measure of their importance to the estuarine system, varied between methods. (4) It was concluded that the morphology of the species, the location, and the general environmental conditions affect the results of any single method and that these factors must be considered before selecting a particular harvest method. In addition, future work should assess the precision of the methodologies.