Petesse M L, Petrere M, Spigolon R J
Departamento de Ecologia, Universidade Estadual Paulista, Rio Claro, SP 13506-900, Brazil.
Braz J Biol. 2007 Aug;67(3):433-45. doi: 10.1590/s1519-69842007000300008.
The temporal succession of fish communities allows evaluating the environmental conditions and the adaptation capacity of the fish species to anthropogenic stress in reservoirs. The fish community at Barra Bonita reservoir was sampled in two different periods of the year (dry and rainy) and in three different areas of the reservoir (fluvial, transition, and lentic). The species list was compared to another four lists, trying to detect the transformations of the fish community for the last 15 years. In order to evaluate the adaptation of the present fish community to the hydraulic management of reservoir, the trophic and reproductive structures were studied. Temporal succession analysis shows little change in fish richness of the communities. The number of fish species varies between 23 and 39 for a total of 68 registered species. From this, 27 can be considered constant, 14 accessory and 27 accidental; the main differences observed were for Anostomidae, Loricariidae and Characidae families. In relation to the hydraulic management, we found a fish community stabilized and adapted to environmental stress. This is characterized by the dominance of small-sized fish species of opportunistic diet and high reproductive compensation (r-strategists). The overlap of biological cycles of the most abundant species with the reservoir level fluctuations points to the period from September to March-April as critical for reproductive success and only the species with partial reproductive strategy or parental care are best succeeded. These results, interpreted in the context of the reservoir aging process, indicate that Barra Bonita reservoir is entering a transition phase, between the colonization and aging stages.
鱼类群落的时间演替有助于评估水库的环境状况以及鱼类物种对人为压力的适应能力。在巴拉博尼塔水库，于一年中的两个不同时期（旱季和雨季）以及水库的三个不同区域（河流区、过渡区和静水湖沼区）对鱼类群落进行了采样。将该物种清单与另外四份清单进行比较，试图检测过去15年中鱼类群落的变化。为了评估当前鱼类群落对水库水力管理的适应性，对其营养结构和繁殖结构进行了研究。时间演替分析表明，群落中的鱼类丰富度变化不大。鱼类物种数量在23至39种之间变化，总共记录了68种。其中，27种可被视为常住物种，14种为附属物种，27种为偶然出现的物种；观察到的主要差异存在于甲鲶科、吸甲鲶科和脂鲤科。关于水力管理，我们发现鱼类群落稳定且适应环境压力。其特点是机会主义食性的小型鱼类占主导地位且繁殖补偿高（r策略者）。最丰富物种的生物周期与水库水位波动的重叠表明，9月至次年3月至4月这段时间对繁殖成功至关重要，只有具有部分繁殖策略或亲代抚育的物种才能最成功地繁殖。在水库老化过程的背景下解读这些结果，表明巴拉博尼塔水库正在进入定居阶段和老化阶段之间的过渡阶段。
