ALGUNAS EXPERIENCIAS EN EL USO DE ÍNDICES LIMNOLÓGICOS EN COLOMBIA

<p>El objetivo central de este trabajo es mostrar algunas experiencias del Departamento de Biología de la Universidad Nacional de Colombia en la elaboración de índices limnológicos para evaluar el estado ecológico de sistemas acuáticos colombianos. Se presentan siete casos que van desde la construcción de un índice multimétrico para los humedales bogotanos, hasta el desarrollo de un método de biomonitoreo del estado trófico basado en microalgas encapsuladas en alginato. Los índices expuestos fueron realizados por docentes y estudiantes de pregrado y posgrado de Biología y consideran tanto variables físicas y químicas como características bióticas de los ambientes limnológicos analizados. Las comunidades acuáticas trabajadas fueron el fitoplancton, el perifiton, las plantas acuáticas y los invertebrados acuáticos. Los índices propuestos (Índice de Condiciones Limnológicas de los humedales de Bogotá – ICOL; Índice de Diatomeas Perifíticas de los humedales de Bogotá – IDPHB; Índice de Integridad Biótica de Macroinvertebrados en ciénagas del Cesar– IIBM; Índice de Estado Limnológico para ciénagas del Canal del Dique – IEL; Índice de Estado Limnológico Fluvial para ríos de la cuenca alta del río Chicamocha– IELf; Índice de Integridad del Hábitat para ríos licenciados - IIH) permiten establecer escalas de calidad y funcionalidad de los ecosistemas estudiados. Las algas encapsuladas, por su parte, reflejan a través de sus tasas de crecimiento la condición trófica del agua. De esta manera se ponen a disposición de las autoridades ambientales una serie de herramientas técnicas y científicas que permiten tomar decisiones sobre el uso, restauración y conservación de los ambientes acuáticos continentales del país.</p><p> </p><p>Abstract</p><p>The main objective of this paper is to show some experiences of the Department of Biology of the Universidad Nacional de Colombia in the development of limnological indices to assess the ecological status of aquatic systems in Colombia. Seven cases are presented ranging from the construction of a multimetric index for the urban wetlands of Bogotá, to the development of a method for biomonitoring the water trophic status, based on microalgae encapsulated in alginate. The indices shown consider physical, chemical, and biotic variables in the limnological environments analyzed. Aquatic communities worked were phytoplankton, periphyton, aquatic plants, and aquatic invertebrates. The proposed indices (Limnological Conditions Index of Bogotá wetlands–LICOI; Periphytic Diatoms Index of Bogotá Wetlands– PDIBW; Biotic Integrity Index for Macroinvertebrate of Cesar swamps BIIM; Limnological State Index for the Canal del Dique swamps–LSI; Limnological River State Index for upper basin of River Chicamocha – LRSI; Habitat Integrity Index for licensed rivers–HII) permit to set ranges of quality and functionality of ecosystems studied. Encapsulated algae, meanwhile, reflected through their growth rates trophic status of water. Thus, technical and scientific methodologies are offered to the environmenta</p>

Development and evaluation of the Lake Multi-biotic Integrity Index for Dongting Lake, China

<p>A Lake Multi-biotic Integrity Index (LMII) for the China’s second largest interior lake (Dongting Lake) was developed to assess the water quality status using algal and macroinvertebrate metrics. Algae and benthic macroinvertebrate assemblages were sampled at 10 sections across 3 subregions of Dongting Lake. We used a stepwise process to evaluate properties of candidate metrics and selected ten for the LMII: Pampean diatom index, diatom quotient, trophic diatom index, relative abundance diatoms, Margalef index of algae, percent sensitive diatoms, % facultative individuals, % Chironomidae individuals, % predators individuals, and total number of macroinvertebrate taxa. We then tested the accuracy and feasibility of the LMII by comparing the correlation with physical-chemical parameters. Evaluation of the LMII showed that it discriminated well between reference and impaired sections and was strongly related to the major chemical and physical stressors (r = 0.766, P&lt;0.001). The re-scored results from the 10 sections showed that the water quality of western Dongting Lake was good, while that of southern Dongting Lake was relatively good and whereas that of eastern Dongting Lake was poor. The discriminatory biocriteria of the LMII are suitable for the assessment of the water quality of Dongting Lake. Additionally, more metrics belonging to habitat, hydrology, physics and chemistry should be considered into the LMII, so as to establish comprehensive assessment system which can reflect the community structure of aquatic organisms, physical and chemical characteristics of water environment, human activities, and so on.</p>

Effect of environmental quality and mesohabitat structure on a Biotic Integrity Index based on fish assemblages of cerrado streams from Rio Cuiabá basin, Brazil

Over the last 30 years, the Cerrado has been experiencing various antropic impacts that have brought about alterations to species composition, structure and functioning of aquatic habitats. Therefore, studies on negative impacts are useful to prevent future damage and restore environmental quality. The objectives of our study were: i) to adapt an index of biotic integrity of streams in the Rio Cuiabá Basin and ii) to analyze if the Index of Biotic Integrity (IBI) correlated with the environmental quality measured by the Index of Environmental Quality (IEQ) and with the mesohabitat structure. We sampled 26 streams in sub-basins of the Cuiabá River. In each stream, we closed a stretch of 50 m with blockage nets and used electrofishing to capture fish. To obtain a measure of environmental quality in sampled units, we characterized the stream and its micro basin. For the analyses, we used the Spearman Correlation, Kruskal-Wallis test and Analysis of Multiple Regression. We collected 697 individuals distributed into 6 orders, 15 families and 49 species. The IBI followed changes on environmental quality measured by IEQ when we removed streams that present natural barriers from the analysis (r² = 0.4; r² = 0.58). Types of land use did not affect the biotic integrity (n = 26; df = 4; H = 4,860; p = 0.302), but natural and artificial barriers affected it (n = 26; df = 4; H = 11,027; p = 0.026). The IBI was not sensitive to variations in mesohabitat structure (F2,23 = 0.373; r² = 0.031; Axe 1 p = 0.620; Axe 2 p = 0.490). The IBI is certainly a reasonable instrument for evaluating changes in the environment, but we cannot ignore the fact that we were able to obtain the same result with any combinations of metrics. This makes its analysis and interpretation difficult.