| Seasonal changes in water volume and water and sediment salinity were monitored at three shallow, closed, saline wetlands in Saskatchewan in 1978 and 1979. Porter Lake, the main study site was dry in 1978 and flooded in 1979. When dry, the salinity of surface sediments was higher than sediments 50-60 cm deep, and those in the lake centre were more saline than at the shoreline. Upon reflooding in 1979, there was a large, immediate decrease in surface sediment salinity and surface layers were less saline than sediments 50-60 cm deep. Over the summer in 1979, the water salinity showed a continuous increase and the mass of dissolved salts within the water volume increased fivefold. The ionic proportions of the major salts within the water remained relatively constant. Differences in the ionic proportions of salts within the sediments at various basin positions and depths, appear to be related to the differences in the solubility of the salts and where they are precipitated as the lake water levels recede. Problems in saline lake classification and management are discussed.; The life cycle and seasonal growth of Scirpus maritimus L. var. paludosus (Nels.) Kuk. were monitored, biweekly, at three wetlands in Saskatchewan in 1978 and 1979. Culms sprout from over-wintered tubers in May and lateral rhizomes extend outward and produce tillers and new tubers. Flowering occurs in late June and seed is ripe by August. Shoot senescence begins in early August and by winter all the shoots die.; Seasonally, the below- to above-ground biomass ratio of the S. maritimus clones increase in late summer. At one site, high water levels and a resulting drop in salinity, increased the peak above-ground standing crop 22-fold (from 27 to 600 g/m('2)) from 1978 to 1979. Maximum stem density reached 380 stems/m('2) by late July, slightly before the maximum standing crop of 625 g/m('2) was attained. A methematical equation predicting S. maritimus seasonal above-ground standing crop was developed using water depth and conductivity as predictor variables.; The distribution and peak standing crop of S. maritimus were monitored at 24 saline wetlands in the Canadian prairies. Scirpus maritimus is found in saline wetlands in the prairie and parkland regions. Within the wetland basins the position and extent of the S. maritimus zone is thought to be dependent upon mudflat salinity during germination and seedling establishment.; Multiple regression analysis showed that S. maritimus standing crop decreased logarithmically with increasing salinity and in water greater than 40 cm deep, individual stems were taller, had a higher rate of flowering and produced larger inflorescences while stem density and proportion of below-ground biomass were reduced compared to shallower depths. The below- to above-ground biomass ratio was highest at shallow water depths and high salinity.; Tubers of S. maritimus may remain dormant during dry periods and sprout when the site refloods. In July and August, at many of the flooded sites, roots on the young tubers were killed, probably by an H(,2)S effect.; Two phytophagous Curculionidae Coleoptera were found to feed upon S. maritimus, Endalus sp. utilising seeds and Sphenophorus aequalis Gyllenhal tubers. The Endalus sp. is parasitized by an Eupteromalus sp. (Hymenoptera:Pteromalidae). Insect distribution, population status, life cycle and their impact upon S. maritimus were assessed. |
