magnitude

The geographic range of a particular plant or animal species is the area in which it can be found during its lifetime. The range of most species is limited by climatic factors, including temperature, precipitation, soil moisture, humidity, and wind. Any changes in the magnitude or variability of these factors will impact the species living there.

For example, a species sensitive to temperature may respond to a warmer climate by moving to cooler locations at higher latitudes or elevations.

But not all species are able to move at the same speed. According to an international research team led by scientists from the University of Massachusetts Amherst, non-native species are expanding their ranges many times faster than native species.

The researchers found that land-based plant and animal species need to be shifting their ranges by about two miles per year just to keep up with the rapid pace of the changing climate. Marine species need to be moving about 1.7 miles per year. However, native species are only managing to move about one mile per year on average.

Non-native species, on the other hand, are spreading nearly 22 miles each year on their own. Additionally, when the role humans play in assisting the spread of non-native species is factored in, the rate jumps to a whopping 1,170 miles per year. This is more than 1,000 times faster than the rate at which native species are spreading.

The researchers conclude that there is no chance for native species to keep up with climate change without human help. Assisted migration needs to be on the table if native plants and animals are to survive.

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Non-Native Plants and Animals Expanding Ranges 100 Times Faster than Native Species

Photo, posted April 10, 2011, courtesy of Bri Weldon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A vast cloud of dust from the Sahara Desert blanketed the Caribbean in late June before drifting across the southeastern U.S. The phenomenon is nothing new; only the magnitude of the occurrence this time around was unusual. According to experts, this is the most significant Sahara dust event in 50 years.

The Sahara Desert is the major source on Earth of mineral dust, with some 60-200 million tons of it per year being lifted into the atmosphere. Convection currents over hot desert areas lift the dust to very high altitudes. From there, it can be transported worldwide by winds. The dust, combined with the extremely hot, dry air of the Sahara Desert often forms an atmospheric layer called the Saharan Air Layer, which can have significant effects on tropical weather by interfering with the development of hurricanes. The Saharan Air Layer typically moves across the North Atlantic every three to five days from late spring to early fall, peaking in the middle of the summer. It can occupy a layer as much as two miles thick in the atmosphere.

The dust plume this summer was highly visible from space, covering thousands of miles of the Atlantic Ocean and the Caribbean Sea.

A common effect of Sahara dust is that normally blue skies can acquire a milky haze, but beyond that can lead to spectacular sunsets. But apart from the visual spectacle, the dust can aggravate the conditions of people with asthma, respiratory illnesses, and allergies. On the positive side, as long as the dust is around, it is much less likely that tropical storms and hurricanes will form.

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Sahara dust blankets Caribbean, air quality hazardous

Photo, posted June 22, 2020, courtesy of Sagar Rana via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.