Not only do
invasive species reduce the biodiversity of the land, but human actions do as
well. A recent study done by Umea
University in Sweden found that river regulation actually harms animals that
live off the land. It reduces the number
of aquatic insects that fly onto the land and provide food for the land-living
animals. The population of flying
insects is lower along regulated rivers, resulting in a decrease of spiders and
insects. Because birds, such as the Pied
Flycatcher, rely on spiders and insects as a food course, they are negatively
affected as well. They lost more weight
after their eggs hatched and fewer of their chicks survived. Not only were just certain species affected,
but whole bird communities as well. The
fact that these effects are still visible a half a century later clearly
indicates that these changes are permanent.
In this
study researchers concentrated on the effect biological insecticides had on the
ecosystem. These insecticides were used
to regulate and reduce the number of mosquitoes among rivers in central Sweden,
but are used all over the world as well.
The results of this study prove that river regulation has a negative
effect on an ecosystem and results in poorer living conditions for a broad
range of land-living animals.
The themes
of nature of science this study has is collaborative, as many researchers
helped contribute to the findings. Also,
it’s based on the evidence that there is less biodiversity of the land living
animals and poorer conditions for them to live in. The study is both credible and repeatable
because there were three different studies conducted to support their results,
all done by credible schools. The
motivation behind this was to explore the different effects that river
regulation had on an ecosystem.
Adding on the part about insecticides, I found a link pointing out the risks of using insecticides. This article talked about how insecticies are usually inspecific, meaning they kill a larger number of species than intended.In the past 30 years, usage has increased by 50%. Also, using pesticides and insecticides provokes resistance to the chemicals so the pests form adaptations often making them even more annoying or harmful. This article points out that only 1% of species are actually considered pests. There are many more risks that outweigh the benefits of using insecticides.
ReplyDeletehttp://www.organicgardeningguru.com/pesticides.html
Rachel Nelson- Hour 1
I agree with what Rachel said, and that this post clearly points out that good intentions do not necessarily work all the time. I did research on the affects of using insecticides by rivers and according to the link posted at the bottom, it stated that an estimated 5.5 million metric tons of nitrogen fertilizer was dumped into the Mississippi River Basin in 1991. It is concerning that while these rivers are being regulated, the amount of insecticides used to kill off the local species has an impact on the food web as a whole! Rather than using pesticides to drive out harmful pests, local biologists and farmers need to work together and intorduce more species of carnivourous beetles such as lady bugs, which affectivly dispose of pests such as aphids.
ReplyDeletehttp://animals.nationalgeographic.com/animals/bugs/ladybug/
http://pubs.usgs.gov/circ/circ1133/pesticides.html
Anthony Plyakov-hour 2