Zedler Joy B, Winfield Ted, Williams Phil
Department of Biology, San Diego State University, 92182, San Diego, California, USA.
Oecologia. 1980 Jan;44(2):236-240. doi: 10.1007/BF00572685.
The effects of altered tidal circulation on southern California salt marshes are investigated by comparing a well-flushed wetland and two modified wetlands which have reduced tidal flow. The Tijuana Estuary had continuous exchange of seawater but relatively low net aerial primary productivity (0.4-1.0 kg myr) of vascular plants. Low productivity (0.6 kg myr) was also found in the Flood Control Channel of the San Diego River, where tidal exchange was restricted to flow through a riprap dike. High productivity (1.2-2.9 kg myr) in Los Penasquitos Lagoon was attributed to the influences of freshwater impounded behind a sand bar which blocked the mouth of the lagoon during much of the study period.It is hypothesized that elimination of tidal flow during the growing season increased primary productivity of vascular plants because freshwater runoff decreased soil salinity and because nutrients were retained within the marsh. However, we predict that sand bar obstruction can decrease productivity if below-average rainfall leads to hypersalinity of closed lagoons. Comprehensive evaluation of the effects of altered tidal circulation requires longterm study and examination of the total ecosystem.
通过比较一个潮汐冲刷良好的湿地和两个潮汐流减少的改造湿地，研究了潮汐循环变化对南加州盐沼的影响。蒂华纳河口有持续的海水交换，但维管植物的净空中初级生产力相对较低（0.4 - 1.0千克/年·平方米）。在圣地亚哥河的防洪渠中也发现了低生产力（0.6千克/年·平方米），那里的潮汐交换仅限于通过抛石堤的水流。洛斯佩纳斯基托斯泻湖的高生产力（1.2 - 2.9千克/年·平方米）归因于在研究期间大部分时间里，一个沙洲阻挡了泻湖口，蓄积了淡水的影响。据推测，生长季节潮汐流的消除提高了维管植物的初级生产力，因为淡水径流降低了土壤盐分，并且养分保留在沼泽内。然而，我们预测，如果降雨量低于平均水平导致封闭泻湖盐度过高，沙洲阻塞可能会降低生产力。对潮汐循环变化影响的综合评估需要对整个生态系统进行长期研究和考察。
