The Mississippi River Valley has become one of the country’s deadliest and most expensive river basins.
The area is home to the nation’s largest reservoir of drinking water, Lake Powell, which is a major source of drinking and irrigation water for hundreds of millions of people in the United States.
And it has been a breeding ground for a wide variety of animals, including the state’s largest, the bald eagle.
But now, as water levels have plummeted, so too has the population.
The Mississippi Valley has experienced a dramatic drop in fish populations and is losing its most important water source: the Mississippi River, which supplies the Mississippi Valley with drinking water.
In addition, the river basin is increasingly being turned into a “ghost town” that has a history of attracting disease, a new study found.
The study, which was published in the journal Science Advances, examined the water quality in the Mississippi Basin from 1950 to 2016 and found a dramatic decrease in fish abundance, especially in areas of low-lying vegetation, low-oxygen conditions, and a lack of water.
The researchers found that there were “no statistically significant trends” in fish stocks, with the most significant declines occurring in areas that were “very low in vegetation, relatively low in oxygen, low in water availability and low in biodiversity.”
The study also found that “a significant decline in fish numbers and abundance occurred in areas where populations were very low in biomass, low biomass, and low oxygen.”
The authors concluded that “these trends suggest that the reduction in fish resources is not primarily due to a decline in water quality but rather the result of habitat loss.”
The findings were “incompatible with the hypothesis that increased land use and human-induced degradation of ecosystems have contributed to a decrease in the abundance of fish populations,” said study co-author Richard G. Schmid, a doctoral student at the University of California, Riverside.
“The overall result is that there is an overall decline in the fish populations in the river, which we call the Mississippi Effect.”
What’s driving the decline?
The authors attribute the decline in population to both natural and human causes, including habitat loss, pollution, and agricultural practices.
“There is no doubt that a large part of the increase in the mortality rates of bald eagles and the decline of fish is related to habitat loss,” said co-first author John A. Kline, a professor of biology at the university.
But the scientists also noted that “some of the decrease in populations is the result [of] pollution, which contributes to the increase.”
The Mississippi Effect is a phenomenon that scientists have been studying for a number of years, but the researchers said their findings were the first to directly compare the two.
“We are seeing a very similar pattern in our study,” said G. William Jones, a hydrology professor at the College of Charleston and a co-authors on the paper.
“Our study shows that there has been an overall decrease in abundance of a number [of fish species] that is very consistent with what we would expect from natural causes.”
Jones said the Mississippi effect is not unique to the Mississippi.
“I don’t think there is a general trend,” he said.
“But what is very clear is that we are seeing the effects of a much greater decline in wildlife populations in our river basin.”
The researchers also found “substantial decreases” in the numbers of large mammals like deer and bison.
And the researchers found a “dramatic decline in populations of the black bear and grizzly bear, both of which are critical to the habitat of other wildlife species.”
What does this mean for the future?
“The Mississippi Effect has been known for many years and there are numerous studies showing that the decline is very, very widespread and not just limited to one or two areas,” said Jones.
“It’s an ongoing phenomenon that we’re seeing across a wide range of regions.”
In other words, the changes in wildlife abundance are being felt throughout the Mississippi, and the effects are being seen across multiple ecosystems.
“These declines have been going on for decades,” Jones said.
“[They] have been increasing rapidly and at a very high rate.”
Jones and Schmid said that more research is needed to understand the causes of the Mississippi effects.
“One of the things we hope to do is to look at the different types of species that are affected, like species that depend on the river and those that are not,” said Schmid.
“So for example, the black bears have a habitat impact on the deer population.
But we want to look more closely at species that live in wetlands, where we can learn about how they interact with other species.”
In addition to the Black Bear and Grizzly Bear, the study also looked at the red deer, which are an important part of their diet, and found that the overall mortality rates for both species have declined.
The authors said their research will allow scientists to better understand how the Mississippi and