Canada geese are native to North America and eastern Siberia and northeastern China. They are migratory birds, and their scientific name is Branta canadensis. We see migrating geese frequently today in the spring and autumn. They fly overhead in V-shaped formations, and you can often hear their honking if you’re outdoors.

Zooarchaeologists examine the bones, fish scales, and other remains of creatures recovered from archaeological contexts to determine which species were important to by-gone peoples.

Zooarchaeological studies so far seem to indicate that migratory waterfowl and migratory birds in general were not a major part of the Native American diet in Georgia and Southeastern North America.

Is this because they were difficult to catch or trap, or because their populations were much lower than today? Or perhaps their bones don’t preserve well, so our collections don’t show them. Or…?

Scientists studying ice cores from Antarctica and Greenland conclude that the Earth’s climate changed rapidly about 14,700 years ago. They studied the oxygen isotopes in air bubbles trapped in the ice. About 14,700 years ago, they found changes in the air that came from increases in vegetation levels. These increases happened over about 200 years, which is quite rapidly.

Credit: Zina Deretsky, National Science Foundation

The press release notes:

The ratio of ¹⁸O to ¹⁶O found in an ice core has shown the history of abrupt climate change on Earth. For example, dry spells around 14,700 years ago resulted in the planet being quite arid north of the equator. Monsoons that followed, caused the proliferation of vegetation north of the equator 14,500 years ago.

Combine this with information from the National Science Foundation’s 2009 report “Solving the Puzzle: Researching the Impacts of Climate Change Around the World.” On page 62, the report says:

Earth’s landmasses support critical ecosystems, host Earth’s freshwater environments, and sustain almost all human agricultural activities. Land separates freshwater from the sea, stores nutrients essential for terrestrial and aquatic life, and holds a fossil record of Earth’s climatic past. As the planet warms, the conditions favorable to many plant and animal species are expected to shift toward the poles. Individual species will differ in their ability to make the same shifts. The resulting altered species distributions will likely cause significant disruptions to established ecosystems, as habitats adjust to new species populations.
Land use is inextricably linked to the carbon cycle. Changing land-use patterns, such as clearing forest to create agricultural plots, change the dynamics of the carbon cycle. Livestock such as cattle contribute a net surplus of carbon to the atmosphere in the form of methane, a powerful greenhouse gas.

Past climate change patterns are not predictors of the rate of change we may be experiencing today.

Undisturbed archaeological remains buried in the soil contain all sorts of chemical clues invisible to the human eye. The oxygen isotopes in the air bubbles in the ice are a similar invisible clue. Visible archaeological remains can also reveal clues as to the climate in the past. What invisible chemical information about the climate of the past do you think may be contained in archaeological sediments, artifacts, and features?

Read the full press release on the Science article by clicking here.

Click here to go to the National Science Foundation’s website, where you can download their 2009 report “Solving the Puzzle: Researching the Impacts of Climate Change Around the World.”

In mid-June 2009 the government of the USA, through the United States Global Change Research Program (USGCRP), released an authoritative assessment of national and regional impacts of global climate change called “Global Climate Change Impacts in the United States.” This initiative was mandated by Congress in 1990 to generate “a comprehensive and integrated United States research program which will assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change.”

In the Southeast region, including Georgia, we are warned to expect:

Effects of increased heat include more heat-related illness; declines in forest growth and agricultural crop production due to the combined effects of heat stress and declining soil moisture; declines in cattle production; increased buckling of pavement and railways; and reduced oxygen levels in streams and lakes, leading to fish kills and declines in aquatic species diversity.

In addition, we are told:

Sea-level rise is projected to accelerate, increasing coastal inundation and shoreline retreat. The intensity of hurricanes is likely to increase, with higher wind speeds, rainfall intensity, and storm surge height and strength.

So, think. What will the effect be on our archaeological heritage?

Rising sea levels over the last 20K years have already inundated archaeological remains on what is now underwater on the continental shelf. If the seas rise further, more lands will be inundated, and Georgia’s shell rings and coastal island sites will be threatened. Increased rainfall will increase the potential for erosion and seasonal flooding, and both can damage our hidden archaeological resources, like buried prehistoric villages and abandoned historic farm sites.

The Southeast Fact Sheet also notes:

Ecosystems provide numerous important services that have high economic and cultural value in the Southeast. Climate change may result in abrupt changes to these ecosystems, such as hurricane-induced sudden loss of landforms that serve as storm surge barriers and homes for coastal communities.

The Executive Summary for the entire assessment notes:

These climate-related changes are expected to continue while new ones develop. Likely future changes for the United States and surrounding coastal waters include more intense hurricanes with related increases in wind, rain, and storm surges (but not necessarily an increase in the number of these storms that make landfall), as well as drier conditions in the Southwest and Caribbean. These changes will affect human health, water supply, agriculture, coastal areas, and many other aspects of society and the natural environment.

What positive and negative effects will these changes in the global climate make to archaeological resources?

Click here to visit the USGCRP website to read about this program and download this report and other information.

Click here to go to the National Science Foundation’s website, where you can download their 2009 report “Solving the Puzzle: Researching the Impacts of Climate Change Around the World.”

What are invasive species? Species are a kind of creature. Invasive species is a phrase that usually refers to a creature that is not native to the area, but becomes resident there; this is the same as discussing non-indigenous species. Sometimes, however, ecologists use the term invasive species to refer to species that heavily colonize an area, but actually were there in lower numbers before; in this case, the word invasive is referring to the high populations of that species. You have to read carefully to know which definition is meant.

There’s another related term: introduced species. Synonyms for “introduced” are non-indigenous, alien, and exotic. An introduced species lives outside its normal distributional range, and arrived because of human intervention.

The pictures show a species of duck called Muscovy duck. Its scientific name is Cairina moschata. The Muscovy* duck species is native to Mexico and Central and South America. Biologists say that the farthest north wild Muscovy ducks range is along the southeast Texas border. Any Muscovy ducks here in Georgia are considered feral populations. Feral populations are escaped domesticated or captive creatures. Muscovy ducks are a non-migratory species. This specimen resides (year-round) in Atlanta’s Piedmont Park.

So, some questions. Are the trees, shrubs, and plants around your county courthouse (or school) native species? Are they introduced species? Are they invasive species? And, are human beings an invasive species? Are human beings in North America invasive?

* The word Muscovy means “from Moscow,” but these birds are not from Moscow; they’re not even from the Old World. The explanation for this term is disputed, but is discussed at length in this Wikipedia entry.