Invasive Species

We all know that invasive species are nonnative species that take over a certain area. This invasion may lead to health, economic and ecosystem problems. They may even lead the native species to extinction through competitive exclusion, niche displacement, or hybridization. But when we think of evolution, what are the effects that these "alien species" have?
When considering invasive species through the lenses of evolution, we see it not as a harm, but as a proof of the capability of some plants to adapt. Invasive species are not good when they lead the native species to extinction, but that is not always the case. Sometimes, these invasive species make the native species adapt to the consequences, and if this evolution occurs fast enough, the change is not necessarily negative. Because of international trade, and tourism,  invasive species have started spreading. They already dominate 3% of all the ice-covered land of the world. If the species are not able to adapt, they will eventually be led to extinction. An example is the soapberry bug. Their beak lengths have varied during the last 50 years in order to adapt to the new invasive hosts. The reality is that international trade is ever-accelerating, which means, that the plants will have to adapt because the invasive species will only spread more and more. That is dangerous because some plants will not be able to adapt on time and will therefore become extinct, but the ones that will, will become stronger and fitter for their environment. So, to conclude, in terms of evolution, invasive species is neither good nor bad. It is just a cause that has evolution as a consequence. Because it happens, plants and animals evolve. Sometimes, evolve to something that they would not need to become if the invasive species was not there, but that is not necessarily bad. As long as they do not change their role in the environment affecting the food chain, the ecosystem will remain stable and the invasive species will have a neutral effect.