Fluctuations of the population of Daphnia laevis Birge 1878: a six-year study in a tropical lake

Brazilian Journal of Biology

Lpm. Brandão²  T. Fajardo²  E. Eskinazi-sant'anna¹  S. Brito²  P. Maia-barbosa² 

[1] ,Universidade Federal de Minas Gerais Instituto de Ciências Biológicas Belo Horizonte MG ,Brazil

关键词: Daphnia laevis;    Brazil;    tropical lake;    temperature;    ephippium;    Daphnia laevis;    Brasil;    lago tropical;    temperatura;    efípio;   

DOI  :  10.1590/S1519-69842012000300010

来源: SciELO

【 摘 要 】

The fluctuation of the population of Daphnia laevis in Lake Jacaré (Middle River Doce, Minas Gerais) was monitored monthly (at one point in the limnetic region) for six years (2002-2007) as part of the Program of Long-Term Ecological Research (LTER/UFMG). The following parameters were also monitored: water temperature, pH, electrical conductivity, dissolved oxygen, chlorophyll a, total phosphorus, phosphate, total nitrogen, nitrate, nitrite, ammonia, and densities of Chaoborus and ephippia of Daphnia laevis in the sediment. A seasonal pattern was observed in the fluctuation of D. laevis, with higher densities recorded during periods of circulation (May-August). A significant correlation was found between the density of D. laevis and temperature (r = -0.47, p = 0.0001), chlorophyll-a (r = -0.32, p = 0.016) and indicators of the lake's trophic status (total phosphorus, r = 0.32, p = 0.007 and trophic state, r = 0.36, p = 0.003), as well as Chaoborus density (r = 0.43 and p = 0.002). These results indicate that changes in the physical and chemical characteristics of the water related with stratification and circulation of the lake may have a direct (temperature, total phosphorous) or an indirect (food availability, presence of predators, ephippia eclosion) influence on the fluctuation of the D. laevis population.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License