During the 2000-2001 hydrological cycle the middle section of the Alfajayucan river system was monthly sampled. 4,052 individuals belonging to 18 taxonomic orders were separated. Insecta was the most abundant group when number of individuals (75.64% of the total) and biomass/m2/yr (58.09%) were considered along the hydrological cycle. Ephemeroptera and Diptera were the taxonomic orders most representative (29.45 and 23.28% of the total of insects). Mollusca was the second greatest group (10.33% and 37.79% for number of individuals and for biomass, respectively). These three major groups were also the most persistent groups in all the periods of the hydrological cycle (flooding, stability and desiccation periods). Plecoptera only appear immediately after the rain season (September). Though the number of individuals/m2 was kept almost constant during the hole hydrological cycle, a significant attenuation in the number of individuals was detected in the end of the rain season (August), when the river reach its highest water flow; and in the middle of the stability period (November), when the river has a constant and stable water flow. This latter period is also the time when the system has its maximum taxonomic order richness (13 orders). On the other hand, the late stability period (December) was the period with the minimum taxa order numbers (2). Data are discussed in relation of the importance of macroinvertebrate community to the stability of the ecological processes of the ecosystem, to preserve and conserve its ecological functioning.
Keywords: Conservation biology, Ecosystem
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA