Organisms have the amazing ability of quickly colonize new areas, if they constitute the appropriate environment. A typical example is represented by the invasive species, imported voluntarily or involuntarily into new (but suitable) parts of the world by human activities and globalization, e.g. the agricultural pests. These are usually well studied cases because of the great negative impact on the ecosystems health and the economy.
Totally different story is for those species that are naturally spreading into new areas. These would be species that adapt to a new environment or that spread because the environment changes (from previously inhospitable to suitable), without humans carring them around. These cases are documented, but why these spreads occur is a topic somehow less frequently studied, I don't really know why! In this study, some colleagues and I have looked at a bumblebee that is protagnist of an astonishingly quick spread from the Balkan into Central Europe. Did you know that its spread started in the 80s? and do you know why the 80s is a very meaningful time for range spread? Did you know that this bumblebee is a forest-lover but that actually it also loves cities? See here for the study
https://www.biorxiv.org/content/10.1101/2020.02.15.950931v1 and the published version is here https://onlinelibrary.wiley.com/doi/full/10.1111/1744-7917.12800
The figure above is a queen of this beautiful bumblebee pictured in Zlin (Czech Republic!) by me in May 2017, the northernmost known locality in Europe (at the moment), only 70 KM from the Moravian Gate (and Poland!)