Can mountain streams indicate global warming? A study explains the phenomenon. Read here

RIVER EDGE,
CALIFORNIA : A study published in the journal ‘Ecological Monographs’ found that a variety of insects, worms and snails living in high mountain streams could be a tool for understanding global climate change or global warming climatic.

A study found that aquatic invertebrates are particularly vulnerable when the climate changes from historic droughts to massive floods.

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

“We’ve found new ways of thinking about biodiversity in high mountain streams in the Sierra because old ways haven’t worked for us,” said Kurt Anderson, associate professor of evolution and ecology and co – author of the article.

The UC Riverside team of ecologists and their UC collaborators have applied a new theory to predict biodiversity in high mountain streams. They recently conducted a survey of aquatic life in California’s Sierra Nevada.

“Classic theories of stream ecology weren’t developed in the Sierras, so we’re embracing a new set of ideas to better explain what we see up there,” Anderson said.

One of these classic theories is the River Continuum Concept, which discusses how river ecosystems function as they move from river sources to larger, more open rivers.

According to the continuum concept, there should be a steady gradient of change from high to low altitudes. The team studied the biodiversity of streams along a gradient, to test concepts like this.

“We saw a change, but only partially and not for the reasons the theory said we should,” Anderson said.

“For example, we found that lakes tended to interrupt the smooth change we were supposed to see,” he added.

The UCR team observed that invertebrate diversity generally increased in down-flowing waters and was lowest in streams immediately below lakes.

“We think lakes can have a disconnecting effect and force downstream waterways to start from scratch in building diversity,” said Matthew Green, UCR ecologist and first author of the new paper.

The team also found a wide variety of life forms in cold, isolated streams upstream. Despite the general trend toward increased diversity downstream, sometimes species differences between isolated upper reaches can be as great as those between upstream and downstream.

“It’s the aquatic lifeforms that are on the precipice of climate change,” said Dave Herbst, a researcher at the Aquatic Research Laboratory in the Sierra Nevada, a UC nature preserve, and co-author of the article.

The areas just below the lakes were dominated by only a few species of invertebrates and insects capable of filtering food particles. Other sites with mixed food sources had more species present.

The team recommended that interconnected running water systems be protected from diversions and habitat damage caused by rampant land development. When the waters are allowed to flow as they should, the number of resources available to the creatures that live there supports greater diversity.

“That’s what will allow these small, but critically important, life forms to thrive,” Anderson said.

“Where intact habitats have been compromised, restoration efforts can be essential to provide the whole ecosystem with resilience in the face of the coming adversities of climate change,” he concluded.

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Teresa H. Sadler