Summary:
In the eastern United States, scientists have found that over time, throughout the 19th and 20th centuries, the species of trees have shifted from oak trees to maples, and less oak. By looking at observations, scientists can tell that it is not climate change that caused this phenomena, but human disturbances within the forests like deforestation, fires set purposefully by humans, and the introduction of invasive species into areas as ornamental pieces, that resulted in the makeup of forests to change pretty dramatically. Because, fire suppression rules started coming about in the early 20th century, less fires resulted in more canopy cover to the forest floor. Because of this, forests became more damp, and dark, which do not support many species native to the area, and maples thrived under the circumstances with more space to flourish. This is known as mesophication, the forest getting more damp, dark, and dense upon the absence of fires. After looking at much data, scientists concluded that "disturbance regimes" caused the vegetation in many forests in the eastern United States to change in composition over time.
Connection:
This article connects with our study of ecosystems and density independent factors. This article shows how human interference, a density independent factor, is responsible for lowering the carrying capacity for a ecosystem, and producing more limiting factors. This is shown through a difference in temperature limiting the population growth of oaks, and as a result limiting the amount of individuals in that species that can live in a ecosystem. In addition, the ecosystem has changed over time because of a difference in many factors resulting in the alteration of the forest's tree composition. By adding in invasives, it takes out many of its competitors in the ecosystem, and changes the food web, resulting in a different ecosystem and different interactions between organisms and their environments. Therefore, this article relates directly to what we have been discussing in class.
Author: Science Daily
Source: Penn State
Date: October 15, 2014
Link: http://www.sciencedaily.com/releases/2014/10/141015112321.htm
What about now, in the 21th century, are there still more maple than oak?
ReplyDeleteAre there any other species of trees that have shifted to another species due to human activities?
ReplyDeleteIn the eastern United States, the red maple is the most abundant tree now. It contains the highest tree population from Nova Scotia to Florida.
ReplyDeletehttp://www.na.fs.fed.us/pubs/silvics_manual/volume_2/acer/rubrum.htm
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ReplyDeleteThat is a great question with a very complicated, and contradicted answer. To summarize for you, 68% of known plant species are endangered, and most of it has to do with deforestation. I do not know if other plants are taking up the area, but one can infer that if there is more space available due to the absence of plants, then other plants will take over the area. However, many humans are taking down ecosystems to build upon their own space. If houses, and buildings are being put there, then other species will not be able to take its place.
ReplyDeletehttp://www.biologicaldiversity.org/programs/biodiversity/elements_of_biodiversity/extinction_crisis/