By: Meteorologist Megan Mulford
Updated: Jul 30th 2019

Wildlife Wednesdays: Shift of Ecosystems in the U.S.

In just the past 49 years, the northernmost ecosystem boundary in the United States has shifted more than 365 miles north, while the southernmost boundary has shifted about 160 miles from the 1970's baseline (shown in Figure 1). With this information, scientists want to create an early-warning system that would give land managers years to even decades time to prepare for an ecosystem shift or collapse. This would significantly help them prepare rather than the shock value of hearing the news and reacting at that time. 

In the world of weather, when tornadoes are indicated on radar or spotted, sirens go off to let the public know of the danger. Ecologists want something like this for the future when there is impending change or collapse of ecosystems. It was long thought that ecosystems respond to external pressure, such as climate change and invasive species, in large and often unpredictable ways. A new study published June 24 in the journal of Nature Climate Change, scientists suggest that ecological responses are much more ordered and predictable then previously thought. How they came up with the conclusion was by analyzing 46 years worth of avian data collected for the North American Geological Survey Program, designed to track bird population. This included more than 400 bird species found within 250 miles wide transect from Texas to North Dakota. Separating bird species into groups based on body masses and analyzing their movement over a 46 year period, the team measured how much and how fast each ecosystem shifted north.

Over time, researchers identified four ecosystem boundaries (with the fourth one showing up in the final decade). The researchers also indicated that, with the northernmost boundary shifting more than the southernmost one, this means a well-documented phenomenon known as "Arctic amplification." This suggests climate change may be the cause of this shift. Other causes could be wildfire trends, invasion of woody plants, energy development, agricultural land, and urbanization. It is also mentioned that grasslands are the most endangered ecosystems in the world due to woody plant takeovers. 

The researchers plan to expand the range of their ecosystem analysis both east and west to study how neighboring ecosystems move in relation to each other and in relation to global drivers. They intend to develop tools used by land managers and conservationists to help with increased warning of a change, with help from private industries to the military. 


Ecosystem
Ecosystems have shifted further north over the past decade. Source: Nature Climate Change Journal
Birds
Research included more than 400 bird species found within 250 miles wide transect from Texas to North Dakota.
Grasslands
Grasslands are the most endangered ecosystems in the world.