Study finds widespread stream biodiversity declines at low levels of urban development

Jun 08, 2011

A new study from biology researchers at Baylor University and the University of Maryland-Baltimore has found that there are 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 two percent of developed land in a . This is much less that what a decade-old analysis widely cited by environmental policymakers suggests that it takes up to 15 percent of like roads or parking lots, or 20 to 30 percent developed land in a given area before local 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. "Perhaps of even greater concern is that the decline of stream-dwelling animals implies that there is chemical pollution that could also be detrimental to via and downstream drinking water supplies. It is unlikely that it's just the rapid runoff of water from the impervious cover that is causing the loss of biodiversity, but more likely that chemical pollution is also responsible."

The researchers used samples from about 2,000 streams around Maryland and compared and land cover datasets to analyze how the water ecosystem and biodiversity responded to various levels of impervious cover, which are areas where of water into the underlying soil is prevented. Roads, and buildings account for the majority of impervious cover.

Published research in recent years has consistently shown a strong relationship between the percentage of impervious cover in a watershed and the health of the receiving stream. Scientists generally agree that stream degradation consistently occurs at relatively low levels of imperviousness, such as 10 to 20 percent. However, when King and his research team applied a new statistical analysis method that they created called the Threshold Indicator Taxa Analysis (TITAN), it showed biodiversity loss at much lower development levels in the study area. In fact, the analysis showed that approximately 80 percent of the biodiversity loss came between .5 and two percent of impervious cover, and the remaining 20 percent of loss came between two and 25 percent.

"This new statistical analysis method is more precise than current methods and when we applied it to real world environments, it revealed a dramatically lower ecological 'tipping point' at which species are threatened," King said. "The implications of these findings are very important in water management strategies."

Explore further: Earthworms as nature's free fertilizer

More information: The study appears on-line in the journal Ecological Applications.

add to favorites email to friend print save as pdf

Related Stories

Aquatic life declines at early stages of urban development

Jun 03, 2010

The number of native fish and aquatic insects, especially those that are pollution sensitive, declines in urban and suburban streams at low levels of development — levels often considered protective for stream communities, ...

EPA's stormwater program needs a significant overhaul

Oct 15, 2008

Radical changes to the U.S. Environmental Protection Agency's stormwater program are necessary to reverse degradation of fresh water resources and ensure progress toward the Clean Water Act's goal of "fishable and swimmable" ...

Recommended for you

Earthworms as nature's free fertilizer

37 minutes ago

Earthworm presence in the soil increases crop yield, shows a new study that was published this week in Scientific Reports. "This is not unexpected," says Jan Willem van Groenigen, associate professor in the ...

A success in managed pressure drilling

47 minutes ago

As one of BP's top 40 wells globally (and the only UK well qualifying for that category in 2012), the successful delivery of the Harding field's 'Producer North East 2a' well (referred to as PNE2a) was crucial to the business. ...

Passion for the natural world clears the waters

54 minutes ago

A toxic legacy has hung over the picturesque northern NSW coastal hamlet of Urunga for almost 40 years. Although now obscured by dense vegetation, the forest of dead melaleuca trees at the edge of a wetland ...

Indonesia to ratify ASEAN haze agreement

5 hours ago

Indonesia's parliament on Tuesday voted to ratify a regional agreement on cross-border haze as fires ripped through forests in the west of the country, choking neighbouring Singapore with hazardous smog.

User comments : 0