Ríos-Pulgarín M I, Barletta M, Mancera-Rodriguez N J
Limnology and Water Resources Group, Limnology Laboratory, Environmental Management Unit, Universidad Católica de Oriente, Rionegro, Antioquia, Colombia.
Laboratory of Ecology and Management of Estuarine and Aquatics Ecosystems, Department of Oceanography, Federal University of Pernambuco, 50740-550, Recife, Pernambuco, Brazil.
J Fish Biol. 2016 Jul;89(1):131-56. doi: 10.1111/jfb.12885. Epub 2016 Feb 11.
The seasonal and interannual changes in the fish, macroinvertebrates and phycoperiphyton assemblages of the Guarinó River were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Niño-Niña/Southern Oscillation (ENSO) between 2007 and 2010. Four samplings (in dry and rainy seasons) were performed per year. Environmental variables (temperature, pH, conductivity, turbidity, oxygen, total nitrogen, orthophosphate, depth and flow rate) were measured. The temporal patterns of the taxonomic compositions for the three assemblages and the functional composition of fish and macroinvertebrate assemblages with respect to environmental variables were examined through canonical discriminant analysis, multidimensional scaling and multiple correlations. The presence and abundance of fishes, macroinvertebrates and algae species were regulated by environmental variables associated with extreme hydrological events, which derived from the natural torrential regimen of the basin and larger-scale phenomena, such as El Niño and La Niña. Fish abundance and richness were significantly correlated with algal density and pH, the macroinvertebrate density was negatively related to the flow rate and the richness was positively correlated with algal density. The algae richness was positively correlated with pH and negatively correlated with the flow rate and nitrogen. The algal density was positively correlated with pH and temperature and negatively correlated with river flow. The phycoperiphyton assemblage exhibited more direct responses in its density and richness to the hydrological changes (r(2) = 0·743 and 0·800, respectively). In functional terms, the El Niño phenomenon was defined by a greater abundance of omnivorous and insectivorous fishes, as well as filter feeders, scrapers and macroinvertebrate predators. During La Niña, a greater abundance of benthic fishes (both detritivorous and insectivorous) and shredder and collector-gatherer macroinvertebrates was observed. Differentiated responses recorded in the community were based on adaptive strategies for the local hydrological regime that enable fast recovery under conditions such as ENSO phenomena. Composition changes according to adaptations to different hydrological scenarios and the predominance of generalists' trophic guilds and species with plasticity in their habits and their ranges of environmental tolerance were found, supporting the habitat templet model.
2007年至2010年期间，研究了瓜里诺河鱼类、大型无脊椎动物和藻周丛生物群落的季节和年际变化，以及与水文循环和厄尔尼诺-南方涛动（ENSO）相关的物理和化学环境变化。每年进行四次采样（旱季和雨季）。测量了环境变量（温度、pH值、电导率、浊度、氧气、总氮、正磷酸盐、深度和流速）。通过典范判别分析、多维标度法和多重相关性分析，研究了三种生物群落的分类组成的时间模式以及鱼类和大型无脊椎动物群落相对于环境变量的功能组成。鱼类、大型无脊椎动物和藻类物种的存在和丰度受与极端水文事件相关的环境变量调控，这些极端水文事件源于流域的自然洪流状况以及诸如厄尔尼诺和拉尼娜等大规模现象。鱼类丰度和丰富度与藻类密度和pH值显著相关，大型无脊椎动物密度与流速呈负相关，丰富度与藻类密度呈正相关。藻类丰富度与pH值呈正相关，与流速和氮呈负相关。藻类密度与pH值和温度呈正相关，与河流流量呈负相关。藻周丛生物群落在其密度和丰富度方面对水文变化表现出更直接的响应（r²分别为0.743和0.800）。在功能方面，厄尔尼诺现象的特征是杂食性和食虫性鱼类以及滤食性动物、刮食性动物和大型无脊椎动物捕食者的丰度更高。在拉尼娜期间，观察到底栖鱼类（碎屑食性和食虫性）以及碎食性和集食性大型无脊椎动物的丰度更高。群落中记录的不同响应基于对当地水文状况的适应性策略，这些策略能够在诸如ENSO现象等条件下实现快速恢复。发现根据对不同水文情景的适应以及具有可塑性习性和环境耐受范围的广食性营养类群和物种的优势地位，生物组成发生了变化，这支持了生境模板模型。
