Tropical Ecology and Conservation [Monteverde Institute]


M.P. Miller



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Publication Date

September 2000


Degraded watersheds are considered a source of pollution input in rivers. The effects of human-caused disturbances and the abilities of rivers to recover from disturbances were analyzed in three rivers in the around the area of Monteverde, Costa Rica. This was done using benthic macroinvertebrate pollution tolerance levels (FBI), turbidity levels, and macroinvertebrate diversity. Diversity was found to be lowest in the disturbed sites of all three rivers (Modified T-test: 0.002 < p < 0.001). A pattern of maximum FBI values and turbidity levels at disturbance sites was also found to exist; and Escherichia coli were present at all sample sites in all rivers. The data from all rivers was combined for each site and regression analyses were performed. This data suggests that human-caused disturbances will result in decreased species diversity, increased FBI-values, and increased turbidity levels. The results also indicate that rivers have the ability to recover from small-scale human disturbances. The findings of this study support the idea that in order to maintain the diversity of both aquatic and terrestrial organisms as well as clean water for human use, humans need to take into account the effects of their actions on river systems. Las cuencas degradadas son una fuente de contaminación en los ríos. Los efectos de las alteraciones causadas por los seres humanos y las habilidades para la rehabilitación de tres ríos en Monteverde, Costa Rica fueron analizados. Eso se hizo usando los niveles de tolerancia de contaminación de los macroinvertebrados (FBI), niveles de turbidez y diversidad de macroinvertebrados. Diversidad fue mas bajo en los terrenos alterados en cada uno de los tres ríos (Modify t-test: 0.002 < p < 0.001). Se encontro niveles de FBI y turbidez máximos en los terrenos alterados; y Escherichia coli se presentó en todos los terrenos en cada rio. Datos de todos los ríos fueron examinados en conjunto para cada terreno y se hicieron análisis de regresión. Este dato indica que las alteraciones causadas por los seres humanos reducen la diversidad y niveles de FBI y presentan una turbidez más alta. También, los resultados indican que los ríos tienen la capacidad para recuperarse de las alteraciones pequeñas causadas por los seres humanos. Las conclusiones de este estudio respalda la idea que los seres humanos necesitan pensar más sobre los efectos de sus acciones en los ríos para mantener la diversidad de los organismos acuáticos y terrestres y agua limpia para el uso de los seres humanos.


Student affiliation: Department of Zoology, University of Wisconsin-Madison Digitized by MVI



Holding Location

Monteverde Institute MVI



The effects of human-caused disturbances on water quality and the capability of river ecosystems to recover from disturbances: using benthic macroinvertebrates as indicators of water quality



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