Hello Friends,

Humans are a very unique in so many ways: our intellect, our resourcefulness and our imagination give us a wealth of power. We are a species which has successfully conquered all the corners of the Earth: from the depths of the oceans to the peaks of the mountains – we have been there. However, with this power of mobility which humans possess can there be a drawback? Many would say no. However, there is a drawback – when we conquered all the corners of the world, we effected the ecosystems that we interacted with caused disturbances and gave rise to unintended consequences.

The next set of articles will focus on the topic of invasive species. Recently, this problem has stemmed from our conquest of the world. Travelling all over the world, often times we disturb ecosystems by introducing species which are not native to an area. This issue is a problem worldwide and has impacts which can be categorised into the two categories of ecological and economic. This means that the problem of invasive species not only effect natural systems but also our economic systems. These are the impacts we will be investigating through the next set of articles. Each article will focus on one invasive species and the effects that it has upon the entire ecosystem it invades.

In this first article we will be focussing upon what constitutes an invasive species and what causes a species newly introduced to an area to become ?invasive?. When a new species is introduced into an ecosystem it is not necessarily invasive. However, when a combination of factors combine, they can lead to it to become invasive. Scientists say that there are two factors which can lead to this: a species? inherent traits or the ecosystem response to the introduction of a species.

Often times, a species may become invasive when it has some traits which give it an advantage against native species in an ecosystem. There are a variety of such traits however when an introduced species possesses them and can hence outcompete the native species in the region, it becomes invasive. The ability to spread through a region quickly, outcompete native species for resources or adapt quickly to a region all can contribute to a species ability to be invasive. Furthermore, a species may have an ability to directly harm native species in a region. An example we will discuss in the articles to come is the yellow starthistle. This plant native to Eastern Europe has spread to both the Eastern and Western Seaboards of the United States. It produces a chemical which negatively effects the growth of plants native to America.

Furthermore, a species can become invasive due to an ecological changes in a given region. One of major ecological changes experienced in ecosystems worldwide is climate change. Due to climate change, often times introduced species which are not invasive and exist at relatively low densities can rapidly adapt to the changes in a way that native species cannot. This can cause an introduced species to become invasive. Other rapid ecological changes – for example a forest fire – can cause alteration to the performance of species in the ecosystem.  

So, now that we have an idea of what an invasive species is and how a species can become invasive we can start to explore some case studies of particular invasive species and investigate how they impact the regions to which they are introduced. Hence, we can gain a deeper insight on what is often an unintended consequence of the global human conquest.

Meanwhile, if you have any questions or comments on this issue then please feel free to ask.

Regards,

Nitish

photo credit: greenberg-art,com