Consider how decisions made by your parents or grandparents have influenced your life. Maybe their decision to live in a city or in the country affected how much time you spent in nature. And perhaps where they settled down determined where you went to school. But what about decisions that your ancestors made tens, hundreds, or even thousands of years ago? Believe it or not, those decisions affect you too!
Let me show you how, by taking a trip back in time to 2000 years ago.
The Roman Empire is at its peak. The Romans are building cities and growing crops to feed armies and emperors. The Empire is growing, and thriving. Imagine Maximus Decimus Meridius (AKA Russell Crowe in the movie Gladiator) leading his troops in a historic battle against the last of the Germanic tribes, saying: “Brothers, what we do in life, echoes in eternity.” Maximus was right: the decisions that those Romans made two thousand years ago are still affecting our environment today.
I call the effects of past land uses on our contemporary environment land use legacies—and I study them as part of my dissertation research.
So what is the land use legacy of the Romans? When Romans farmed their land, they tilled the soil, removed the native plants that grew there, and replaced them with their own crops. By altering the soil and vegetation composition, the Romans created restrictions on what vegetation could grow there. Today, the canopy trees and understory vegetation (like shrubs) that grow on their former fields are very different than the trees and shrubs growing on land that was not farmed by Romans. But how do we know where the Romans farmed their land? Scientists may use archaeological sites, or they may analyze soil properties or investigate old maps to decipher the impacts of past generations on the environment. This is just one example of a land use legacy. Other ancient societies changed the environment in similar ways, leaving their imprint on future generations.
The problem is that when past societies changed their environment they created limitations on how we can use or benefit from that land today. This is very important, because the once endless potential of our environment has been greatly reduced by human land use. Think of a city: once buildings are in place, it becomes very hard to change the use of that land to something else, let alone revert it to wild forest. This is true for other human-influenced landscapes too. As we change the landscape, it becomes harder and harder to find places with no prior limitations set by past generations, so that we can efficiently grow our food to feed the increasing world population or protect nature in order to conserve wildlife and save threatened species from extinction.
I have devoted my doctoral dissertation research to finding out where past societies created the greatest limitations to our environment and to understanding how long those limitations persist. To do this, I spend time analyzing really amazing maps of empires from hundreds of years ago, and comparing them with the most recent maps, made using satellite images taken from space. I find where and when people altered their environment in the past, and how those actions affect environmental change today. For example, using old maps I can find those places where past generations grew crops or harvested forests. I analyze where environmental change is happening today (deforestation, agricultural abandonment) and model its relation to those historic land uses.
And I find legacies everywhere. It turns out that forests are more likely to be harvested in places that had no forest in the past, and that agricultural abandonment is not as prominent if fields were farmed for very long time periods.
Of course, the land use legacies of my own ancestors are the most interesting to me. I work in Eastern Europe, which is where I’m from, and I find widespread evidence of the environmental footprint of the Ottomans, the Habsburgs, and the Soviets. For instance, in the late nineteenth century, as the Habsburgs expanded their influence eastwards, they planted trees where there had never been forest before. Because they needed timber quickly, they planted mostly spruce trees. Spruce is a fast growing species that acidified the soil, so much so that almost no other species of plants can live there today. These forests are now vulnerable—stands of spruce could be destroyed by stressors like disease or extreme weather events, and are not providing suitable habitat for other forest plants and animals. In other parts of their Empire, the Habsburgs cleared old forests for farming, to feed the growing agricultural demand in the cities of Vienna and Budapest. Those fields have been farmed for over a century now. Today, we struggle with the fact that land farmed for that long is much harder to revert to wilder uses than land farmed for only the past decade.
I believe these land use legacies are fascinating—and not just for those of us who like to look at old maps. They are important for all of us, because they can help us better understand the limitations in our environment. Knowing these constraints can help us make better decisions about how to best manage our land to produce food and to protect nature. My hope is that with this information in hand, we will all be able to leave a better legacy for generations to come, because as Maximus said, “What we do in life echoes in eternity.”
Featured image: screenshot of one of the maps from Catalina’s research.
Catalina Munteanu is a graduate student in the Forest & Wildlife Ecology Department at UW Madison, studying historic and contemporary environmental change in Eastern Europe. She is fascinated by the ecology of human shaped landscapes and in her PhD thesis she quantifies the effect of historic land use decisions on current environmental change. In her free time, she loves to spend time outdoors and to craft. Website. Contact.