Watershed Influence on the Macroinvertebrate Fauna of Ten Major Tributaries of the Colorado River through Grand Canyon, Arizona

The biota of ten major tributaries of the Colorado River through Grand Canyon, Arizona, were examined bimonthly in 1991 and annually in 1993, 1994, and 1996. Identification, distribution and phenology of 42 insect genera are reported. We found significant variability in macroinvertebrate biomass bet...

Full description

Saved in:
Bibliographic Details
Published in:The Southwestern naturalist 1999-03, Vol.44 (1), p.17-30
Main Authors: Oberlin, Gaye E., Shannon, Joseph P., Blinn, Dean W.
Format: Article
Language:English
Subjects:
Aquatic insects
Biomass
Canyons
Creeks
Food security
Freshwater
Insecta
Macroinvertebrates
Primary productivity
Streams
Tributaries
USA, Arizona
USA, Arizona, Colorado R
Watersheds
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The biota of ten major tributaries of the Colorado River through Grand Canyon, Arizona, were examined bimonthly in 1991 and annually in 1993, 1994, and 1996. Identification, distribution and phenology of 42 insect genera are reported. We found significant variability in macroinvertebrate biomass between tributaries and seasonal differences within tributaries. Some of these differences can be explained in terms of stream source and watershed characteristics. Spring-fed tributaries originating within the Grand Canyon had higher macroinvertebrate biomass than tributaries draining large watersheds from outside the Grand Canyon. Tributaries that receive a substantial amount of their water from terrestrial runoff typically are less stable, have higher turbidity, and fewer food resources so that fewer species and/or individuals can be sustained. Irrigation, grazing, and other land use practices that reduce flow and increase sedimentation within these watersheds may have repercussions far downstream of where they occur. /// La biota de diez tributarios mayores del Río Colorado a través del Gran Cañón, Arizona, fueron examinados bimestralmente en 1991 y anualmente en 1993, 1994, y 1996. La identificación, distribución, y fenología de 42 géneros de insectos son registrados. Encontramos una varíedad significativa en biomasa de macroinvertebrados entre tributarios tanto como diferencias estacionales dentro de tributarios. Algunas de estas diferencias pueden ser explicadas en términos de las características del nacimiento de los tributarios y de las cuencas. Los tributarios de origen manantial dentro del Gran Cañón tenían mayor biomasa de macroinvertebrados que los tributarios alimentados por cuencas grandes de fuera del Gran Cañón. Los tributarios que reciben gran cantidad de agua proveniente de terrenos de desagües son típicamente más inestables, tienen mayor turbiedad, y menos recursos de comida por lo que menos especies y/o individuos pueden ser sostenidos. Regar, pastar, y otras prácticas de uso de la tierra que reducen el flujo e incrementan la sedimentación dentro de estas cuencas pueden tener repercusiones mucho más río abajo que de donde ocurren.
ISSN:0038-4909