Could mountain currents indicate global warming? Study explains phenomenon

The study found that water based invertebrates are particularly vulnerable when the climate changes from historical drought to widespread flooding.

The survival of these invertebrates has become a matter of concern to ecologists, as they serve as food for other forms of alpine life such as birds, bats, frogs and fish.

“We’ve come up with new ways of thinking about biodiversity Alp Sierra currents because the old ways were not successful for us,” said Kurt Anderson, associate professor of evolution and ecology and a co-author of the article.

A team of UC Riverside ecologists and their UC collaborators have applied a new theory to predicting biodiversity in high mountain streams. He recently conducted a survey of aquatic life in the Sierra Nevada, California.

“The classic theories of stream ecology were not developed in the Sierras, so we are adopting a new set of ideas to better explain what we see there,” Anderson said.

One such classic theory is the river continuum concept, which discusses how stream ecosystems function as they move from stream sources to larger, more open rivers.

According to the concept of continuum, there should be a smooth gradient of change from higher to lower altitude. To test such concepts, the team conducted surveys for biodiversity along a gradient.

“We saw a change, but only partially and not because of the reasons the theory told us,” Anderson said.

“For example, we found that lakes disrupt the spontaneous change we wanted to see,” he said.

The UCR team observed that the diversity of invertebrates typically increased in downstream waters and was lowest in the steam just below lakes.

“We believe that lakes may have a disconnecting effect and that downstream waterways are restarting in building diversity,” said Matthew Green, a UCR ecologist and first author of the new paper.

The team found a wide variety of life forms in the headwaters, even in cold, isolated streams. Despite the general trend of increasing diversity going downstream, sometimes, species differences between different headwaters can be as great as between upstream and downstream.

“These are the aquatic life forms that are most vulnerable to climate change,” said Dave Herbst, a researcher at the Sierra Nevada Aquatic Research Laboratory, a UC Natural Reserve, and a co-author of the paper.

The areas just below the lakes were dominated by invertebrates and only a few species of insects that had the ability to filter food particles. More species were present in other sites with mixed food sources.

The team recommended that interconnected running water systems be protected from diversion and habitat loss due to unrestrained land development. When water is allowed to flow, the number of resources available to the organisms that live in it supports a high diversity.

“This is what will allow these small, but vitally important life forms to thrive,” Anderson said.

They conclude, “Where intact habitats are compromised, restoration efforts may be critical to providing entire ecosystems with resilience to the impending adversities of climate change.”