Sarah Jackman
Author: Josie Garthwaite
Published: March 5, 2014
http://www.smithsonianmag.com/science-nature/remnants-prehistoric-plant-pollen-reveal-humans-shaped-forests-11000-years-ago-180949985/?no-ist
Summary:
A study was conducted in which paleocologist, Chris Hunt, collected and analyzed pollen from the tropical rain forests of southeast Asia in countries such as Borneo, Vietnam, and Thailand. Previous scientists believed the rain forests had been almost untouched by human influences, but in fact, the pollen showed evidence that humans had "shaped the landscape" for thousands of years. 11,000 years ago, humans imported seeds, cleared land, and cultivated plants for food. In tropical rain forests, it is hard to detect former human habitation due limited areal view(due to the canopy) and slow excavation. Pollen was used because it could survive for thousands of years. Hunt found evidence of fruiting trees, which indicated people cleared the forest vegetation to plant them. Pollen was also taken from areas of the rain forests in one region that were isolated and unlikely that any humans would have inhabited. The pollen samples were compared to find out if they had similar succession patterns because they were under the same conditions. The samples did not match up, which implied that humans interfered with the natural succession of the plants by clearing and cultivating the land. Throughout history all over the world, pre-agricultural people burned areas to improve hunting and promote growth of weedy edible plants. Also, some pollen from 6,500 years ago contained charcoal evidence of fire.
Connection:
This article connects to what we have learned about in class this current unit, as well as past units. The researcher Chris Hunt used the pollen to find evidence. We learned in class how pollen contains the male sperm. Pollen is in abundance in the rain forest because there are so many plants there. Pollen can also survive harsh environments for a substantial length of time. It is likely there was a mix of wind pollinated plants and animal pollination plants because there is such a diversity of plants in the rain forest. In class, we also learned about the difference between wind and animal pollinated plants such as that wind pollination occurs in gymnosperms and angiosperms while animal pollination only occurs in angiosperms. This connects to previous term units including biomes, and isolation.The article focuses on the rain forests in east Asia.We discussed in class how the amount of rainfall and climate in rain forest regions were the cause of the diversity of plants. We also discussed how isolation can lead to the adaptive radiation of species of plants and animals.
How does the discovery that humans influenced the growth of rainforests change how we act towards rainforests today? How does this discovery change our understanding of rainforests?
ReplyDeleteIn the separate countries that were researched, though they are similar environments, were the mechanisms that humans were thought to have used to change the environment and vegetation different? If so, in what way did those specific mechanisms change the environment/ how are those changes reflected in the rainforests today?
ReplyDeleteNo, the mechanisms used to change the environment were mainly fire. There were traces of charcoal on the pollen samples collected by the researchers. When there are forest fires, weedy grasses grow from the charred ground. The main indicator that humans were the ones that set fire to the forest in order to clear the land, was the presence of fruiting trees instead of the usual grasses. This is a logical conclusion because the humans would use the fruiting trees as a source of food. By the humans planting the fruiting trees, they interrupted the natural succession of the area. They changed what plants were able to fill certain niches. As a result, different plants and animals have survived to present day compared to the plants and animals that would have survived if not for the human interference.
Deletehttp://www.smithsonianmag.com/science-nature/remnants-prehistoric-plant-pollen-reveal-humans-shaped-forests-11000-years-ago-180949985/?no-ist