ecosystems – BioQuakes

In the article I came across, it discusses an “alien invasion” of sorts; however, this isn’t just any alien. In fact, this alien can be under your feet right now: non-native earthworms. Earthworms (not the alien kind) are described as “[m]ostly invisible and largely unappreciated” – these friendly creatures are invaluable to not only farmers and gardeners but you! In fact, these creatures support a lot of the agriculture you have grown to love and enjoy. “What makes them so helpful?” I’m sure you’re asking. Well, mainly, earthworm movement leaves an unimaginable amount of tunnels that allow air, water, and important nutrients to penetrate deep into the soil. On top of that, their waste doubles as a rich fertilizer!

Earthworms are far from always being sunshine and rainbows, though. When the wrong type of earthworm reaches the wrong type of ecosystem, chaos can easily ensue. This is what’s happening now all across North America with alien earthworms. Research has shown that, specifically in the northern broadleaf forests of the U.S. and Canada, alien earthworms have caused severe stress on local trees such as sugar maples – Acer saccharum – by altering the microhabitat of their soils. Even more, it is affecting local farmers as well. This microscopic impact can cause a snowball effect, allowing invasive species of plants to spread in an expedited manner. Isn’t it interesting and ironic that an organism known for actually improving soil can lead to poorer-quality crops and lower yield rates?

The article also spoke about specific research – drawing on extensive records spanning from 1891 to 2021, researchers compiled a database encompassing native and alien earthworm species. This dataset was augmented by another documenting interceptions of alien earthworms at U.S. borders from 1945 to 1975. Combined with new machine learning techniques, the team reconstructed the probable pathways of origin and spread of alien earthworm species. Their analysis revealed the presence of alien earthworms in a staggering 97% of soils studied across North America, with a higher (and extremely concerning) presence observed in the northern regions compared to the southern and western areas.

Alien earthworms constituted 23% of the continent’s total of 308 earthworm species and comprised 12 of the 13 most widely distributed species. The article gave a fascinating contrast as well: only 8% of fish species, 6% of mammal species, and 2% of insects and arachnids in the U.S. are of alien origin. Lead author of the study, Jérôme Mathieu, an associate professor of ecology at the Sorbonne, emphasized that these proportions are likely to increase even more due to human activities, posing a significant threat to native earthworm populations, and to the future of our agricultural sector.

In terms of linking this back to our AP Bio course, it is easy to mention how we just learned about food webs, food chains, and trophic levels. We learned how delicate these intricate ecosystems are, and learned that when invasive and non-native species are introduced into an ecosystem, it (the ecosystem) becomes prone to collapse. Further, we can continue to apply this to the genetics unit that we are learning right now; as earthworms change the fundamental pH and nutrients in the soil, new adaptations will likely need to arise to, well, adapt to new conditions.

Who knew that such a small creature could have such a huge (and dangerous) impact on the ecosystems around us? Let me know what you think about it.

A team of researchers, lead by Dr. Adriana Vergés and Dr. Fiona Tomas, has recently discovered a species of tropical fish that “poses a major threat to the entire Mediterranean basin.” The species, called a rabbitfish has greatly harmed the algal forests in the Mediterranean Sea, primarily the eastern portion. The rabbitfish arrived in the waters of the Mediterranean through the Suez Canal. The rabbitfish are not indigenous to the Mediterranean waters, which makes them so dangerous to the ecosystem. This phenomenon has also been observed in lionfish, snakehead fish, and other organisms that are not indigenous to the location that they are harming. The rabbitfish have been eating seaweed and other ocean plants, which provide shelter and food for other species.

The scientists conducted their study by examining 1000 kilometers of coastline in the eastern Mediterranean specifically Turkey and Greece. Both places two separate species of rabbitfish have come to inhabit. The two areas focused upon were warm and cold regions. In the warmer regions the rabbitfish were present while in the colder regions they were not. The warmer regions filled with rabbitfish had a much lower abundance of seaweeds, and were mostly barren rocky bottoms. On the other hand the colder climates had a thriving ecosystem. There was a 60% reduction in algae and invertebrates and 40% reduction in overall species present in the warm rabbitfish filled environment. After filming rabbitfish as well as indigenous species scientists realized that rabbitfish didn’t actually eat more algae than other fish. However, the distinction was that rabbitfish ate both young and adult algae while indigenous species only ate adults. Eating the young and growing algae before it has a chance for reproduction quickly reduces the overall population.

This topic interested me not only because of my love for marine biology, but also because marine sustainability is extremely important to humans. Without oceans there would be no human life on Earth. The abundance of water is what separates a lush green planet like Earth from the rest of the planets in our solar system. In addition the marine ecosystems are very important, and there have become more and more invasive species due to changes in the environment. Fish such as the rabbitfish threaten whole ecosystems as well as hundreds or even thousands of species that rely on those ecosystems.

Should humans attempt to stop this infestation of rabbitfish? If so, what should be done?

http://www.sciencedaily.com/releases/2014/09/140918101635.htm

http://www.digitaljournal.com/news/environment/tropical-rabbitfish-denuding-the-mediterranean-sea/article/404034

http://www.liveaquaria.com/product/prod_display.cfm?c=15+1926+1449&pcatid=1449

BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: ecosystems

Aliens!!! – Not the Ones You’re Thinking of, Though…

Invasive Rabbitfish

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