• Tristan H

Grasslands - A Lost Ecosystem



If you were to find yourself in the Midwest you would likely be surrounded by fields of corn or herds of cattle, however, look back only 200 years and you find an infinite expanse of wilderness.

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The American prairie is a North American temperate grassland ecosystem that spanned 240 million acres (approximately twice the size of Thailand). The flora of this ecosystem consisted of grasses, shrubs, and other small flowering plants, most notably home to the plains Bison whose numbers were estimated to be over 60 million at their peak. Unfortunately, this ecosystem is a mere shadow of its former self; the remaining protected areas only represent a fraction of the historical size. So, how did this ecosystem collapse?



Pre - 1800


Before 1800, the Prairie was practically untouched virgin wilderness. It was also home to hundreds of thousands of native Americans. The most notable species of fauna were the Plains bison, Pronghorn antelope, Grizzly bear, Prairie dog, and many other animals. However as western expansion started to boom, commencing with the California gold rush of 1848, the rapid demise of the prairies would begin.



The Demise of Prairies



At the end of the civil war, westward expansion increased at unprecedented rates and soon the prairie would be caught in the crossfire of a large-scale war between the Natives and the Americans. On June 25, 1876, Custer; A famous lieutenant colonel, the figurehead of westward expansion, and his men fought against the Lakotas and Cheyennes in the battle of Little Bighorn. This battle signified one of the Native Americans' last attempts to preserve their territory's way of life (a lot of which revolved around the plains bison). In this battle, defeated by the Lakotas and Cheyennes, Custer and most of his men were killed. Politicians back in Washington were outraged, resulting in the devising of a new plan; kill all the bison which would eliminate the Native Americans' way of life. This plan was unfortunately successful. Within the course of a 13 year period (1868-1881), over 30 million bison were killed. The Native Americans were forced to surrender and were put into one of the many reservations across the US. Without the Bison, the cornerstone of the ecosystem was gone. Ranchers and farmers would soon flock to claim land and buy acres by the penny. Little of the prairie would be protected and almost all unprotected land would be encroached upon and turned into cropland or land dedicated to cattle grazing. This marked the massive demise of a once robust and fertile ecosystem.



Europe and Asia



Though the North American prairies are sizable, they fail to compare to the Eurasian steppe. This ecosystem spanned one-fifth of the world’s circumference. Notable fauna includes saiga antelope, Przewalski horse, and the Bactrian camel. This ecosystem has been especially significant throughout history. This generally flat expanse of grassland made travels on horseback efficient and effective. Many groups moved through this region on horsebacks such as the Huns and Mongols. The way of life for many people in this region still remains the same; herding cattle over vast expanses of land. Similar to the people, this ecosystem still remains largely preserved. This is a result of the very low population densities found here. This ecosystem, though less notably still, is a diverse and productive ecosystem.



Africa



There is likely no grassland as impressive as the African savannah. From the towering giraffes to the herd of wildebeest, the African savannah is home to more megafauna (animals weighing over 1,000 kg) than all other ecosystems in the world combined. The animals that live here range from the “big five”; Lions, Leopards, Rhinoceros, Elephants, and the Cape buffalos all the way to the elephant shrew. The Serengeti is likely the pinnacle of this savannah grassland. The greater Serengeti-mara ecosystem spans over 30,000 square kilometers. Every year in the Serengeti, a great migration in which over 1 million wildebeest migrate almost 500 kilometers takes place. Serengeti also is home to the highest density of large predators such as lions or cheetahs. These factors all make Serengeti one of the most vital biodiversity hotspots in the entire world. However, much of Africa's native grassland is under threat by the massive population boom. Fortunately what remains of Africa’s national parks is largely protected, however poaching still remains a threat to these ecosystems. Hopefully, they will still continue to prosper into the far future.



Carbon Capture


Recently the idea to use the ecosystem as a method of carbon sequestration has been widely considered since it could help slow down climate change. The go-to ecosystem in this scenario is forests, specifically rainforests. However, an ecosystem not talked about nearly enough is grasslands. Firstly, grasslands sequester and store CO2 much more effectively than forests. While forests store carbon in trees, grasslands store it in the soil. A forest's CO2 capture capacity is limited by the total carbon within the trees. When a tree dies and decomposes, the CO2 it has captured over its entire lifetime is released. On the contrary, since all the CO2 in grasslands is stored in the soil, when the grass dies there is no release of CO2. As a result, much more CO2 can be sequestered and stored.


Recently, as a result of climate change, we have witnessed massive forest fires. Therefore, all carbon stored in these trees (some hundreds of years old) is released. This is why currently Canada's forests are actually producing more CO2 than absorbing. While grasslands do release some CO2 when burnt, the levels are far lower since most of the carbon is in the soil.


Finally, grasslands simply absorb carbon at a much faster rate. Trees grow at a slow rate, hence new seedlings being planted are not going to absorb as much CO2 for decades until they become mature. On the other hand, grasses grow quickly and even their deep root system (up to 6 meters deep) can reach its full extent within a decade. As a result, an acre of pristine grasslands can sequester nearly as much CO2 as the Amazon rainforest.



The Future of Grasslands


As we find out more about the importance of this once disregarded ecosystem, we realize it needs to be preserved. There are still many pressures on the ecosystem, such as agriculture and other forms of human development. These factors remain the largest threat to grasslands. Hopefully, as more individuals realize the importance of Grassland ecosystems, more protection will be put into place. As for now, we must do our best to spread awareness of their importance.



References


https://www.nps.gov/tapr/learn/nature/a-complex-prairie-ecosystem.htm


https://www.flatcreekinn.com/bison-americas-mammal/


https://www.seedsource.com/medicine/history.asp


https://www.worldwildlife.org/places/northern-great-plains


https://www.nps.gov/libi/index.htm


https://www.flatcreekinn.com/bison-americas-mammal/


https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/eurasian-steppe


https://www.nationalgeographic.org/encyclopedia/steppe/


https://www.nationalgeographic.com/animals/article/africa-big-five-safaris-lions


https://www.sciencedirect.com/science/article/pii/S2212041619301068#:~:text=The%20Greater%20Serengeti%2DMara%20Ecosystem%20


https://climatechange.ucdavis.edu/news/grasslands-more-reliable-carbon-sink-than-trees/#:~:text=Unlike%20forests%2C%20grasslands%20sequester%20most,in%20woody%20biomass%20and%20leaves.&text=When%20fire%20burns%20grasslands%2C%20however,more%20adaptive%20to%20climate%20change.