Baylor study: stream biodiversity declines at low levels of urban development
A new study from biology researchers at Baylor University and the University of Maryland-Baltimore has found consistent and widespread declines in stream biodiversity at lower levels of urban development more damaging than what was previously believed.
The study found that aquatic life actually shows significant loss of biodiversity with less than 2 percent of developed land in a watershed. This is much less than what a decade-old analysis widely cited by environmental policymakers suggested—that it takes up to 15 percent of solid surfaces like roads or parking lots, or 20 to 30 percent developed land in a given area before local water systems can no longer sustain normal aquatic life.
"The findings are alarming and imply that water quality in streams is degraded rapidly with relatively low levels of development, which clearly has significant implications to the organisms that live in these streams," said study co-author Dr. Ryan King, associate professor of biology at Baylor.
The researchers used samples from about 2,000 streams around Maryland and compared satellite imagery and land cover datasets to analyze how the water ecosystem and biodiversity responded to various levels of impervious cover, or areas where infiltration of water into the underlying soil is prevented. Roads, parking lots and buildings account for the majority of impervious cover.