At the end of the 19th century, the border region between Italy and Slovenia had mountains with no trees. A massive reforestation ordered by the Austro-Hungarian Empire allowed to recover forests and revitalize the region. Now, however, those pines planted a century ago are in danger.
Evolution leads to an increasing number of species, and that's why it is so difficult for us to know how many of them inhabit the Earth. Should we spend efforts to conserve all of them or would it be enough with just a few?
Nature establishes relationships between species and organisms, forming a very complex network where often great-interconnected nodes appear. They are called 'hubs'. But humans also create this kind of networks, such as airports as nodes and flights as connections.