Vareschi E, Vareschi A
Zoological Institute of the University of München, Seidlstr. 25, D-8000, München 2, Federal Republic of Germany.
Oecologia. 1984 Jan;61(1):70-82. doi: 10.1007/BF00379091.
Consumer biomass and spatial distribution in the equatorial alkaline-saline Lake Nakuru were studied from 1972-1976. These data will provide the basis for estimating feeding and production rates and for quantifying energy flow at the consumer level. Two of the main consumers, the Lesser Flamingo (Phoeniconaias minor) and the Soda Tilapia (Sarotherodon alcalicus grahami), were covered by earlier papers. The biomass of the only planktonic crustacean, the copepod Lovenula (=Paradiaptomus) africana was very high (1.5 gDW (dry weight)·m, mean in 1972/73) in comparison with other tropical lakes. Lovenula was absent in 1974 and 1975, and at very low levels (0.1-0.4 gDW·m) in part of 1976. Among the rotifers Brachionus dimidiatus dominated in 1972/73 (≈0.2 gDW· m), but was outnumbered by B. plicatilis throughout most of 1974 to 1976 (mean total rotifer biomass 1.4 gDW· m, peak densities 7 gDW·m); during high salinity periods (>20‰) Hexarthra jenkinae occurred in very low numbers. For short periods rotifers can be the dominant species of L. Nakuru. Aquatic heteroptera (four species) played a minor role: they contributed 0.4% to total consumer biomass in 1972/73; in 1974-1976 the lake had no aquatic heteroptera. Benthic biomass (0.4 gDW·m) was within the range of other tropical lakes, it consisted almost exclusively of Leptochironomus deribae. Bird counts of the twelve most important species are given for the years 1972-1974: Pelecanus onocrotalus accounts for ≈90% of the biomass (0.44 gDW·m, mean 1972/73) with peak densities of almost 20,000 birds.-The consumer organisms covered by this and the two preceding papers represent >99% of L. Nakuru's consumer biomass. Population dynamics of various consumer species are discussed.
1972年至1976年期间，对赤道碱性盐湖纳库鲁湖中的消费者生物量和空间分布进行了研究。这些数据将为估算摄食率和生产率以及量化消费者层面的能量流动提供依据。之前的论文已涵盖了两种主要消费者，即小火烈鸟（Phoeniconaias minor）和苏打罗非鱼（Sarotherodon alcalicus grahami）。唯一的浮游甲壳动物——非洲哲水蚤（Lovenula (=Paradiaptomus) africana）的生物量与其他热带湖泊相比非常高（1972/73年平均为1.5克干重·平方米）。1974年和1975年没有非洲哲水蚤，1976年部分时间其数量也非常少（0.1 - 0.4克干重·平方米）。在轮虫中，1972/73年二裂臂尾轮虫（Brachionus dimidiatus）占主导（约0.2克干重·平方米），但在1974年至1976年的大部分时间里，褶皱臂尾轮虫（B. plicatilis）的数量超过了它（轮虫总生物量平均为1.4克干重·平方米，峰值密度为7克干重·平方米）；在高盐度时期（>20‰），詹氏六腕轮虫（Hexarthra jenkinae）数量极少。在短时间内，轮虫可能成为纳库鲁湖的优势物种。水生半翅目昆虫（4种）作用较小：1972/73年它们在消费者总生物量中占0.4%；1974年至1976年湖中没有水生半翅目昆虫。底栖生物量（0.4克干重·平方米）在其他热带湖泊的范围内，几乎全部由德氏细摇蚊（Leptochironomus deribae）组成。给出了1972年至1974年12种最重要鸟类的数量统计：白鹈鹕（Pelecanus onocrotalus）占生物量的约90%（1972/73年平均为0.44克干重·平方米），峰值密度近20000只鸟。本论文以及前两篇论文所涵盖的消费者生物代表了纳库鲁湖消费者生物量的99%以上。文中讨论了各种消费者物种的种群动态。
