During the 40s in past century, about 20 beavers were brought from Canada to Tierra del Fuego at the South of Argentina.
The intention behind this was to grow a local population and then start a beaver fur business, however one factor was not taken into consideration: the temperatures in Tierra del Fuego are not as cold as in the forests of Canada, so the beavers won't develop the same kind of hair as in their natural environment, their fur was not attractive for business.
As a result the business was non-viable and the beavers were abandoned in an environment where they don't have any natural predator so their population started to grow without control. Fast forward almost 80 years later the beaver population is estimated now in over 100.000.
This may sound harmless, however has a profound impact on the local ecosystem. By instinct, the beavers continue to build dams to protect their homes, some of those dams can be as big as half a soccer field and according to a report from the Agronomy Faculty of the University of Buenos Aires from 2017 (*) there are no less than 70.000 of those dams, flooding around 100 sq Km and destroying the vegetation on those areas, which in turn affects the life of other animals in the region.
For additional information, here is the report from UBA (University of Buenos Aires) in Spanish:
http://sobrelatierra.agro.uba.ar/castores-advierten-sobre-el-alcance-de-la-invasion/
Also a few local articles about the topic, also in Spanish:
https://www.lanacion.com.ar/2035365-alerta-en-tierra-del-fuego-castores-construyeron-mas-de-70-mil-diques-y-cambiaron-el-ecosistema
https://elpais.com/internacional/2018/03/18/argentina/1521392097_988892.html