Biological conservation is important for ecosystem functioning. How ecosystems works is the reason behind all the commodities we enjoy. For example, due to dense forests, a lot of water is filtered trhough soil. This water replenishes underground streams, which ultimately allow us to filter that water. It's like forests are a giant and very effective mechanism to catch rain water. Besides, vegetation is pretty important for climate regulation in land, since it produces the oxygen we breath and gives shade from the sun. Any economical develpment could provide the benefits forests give. Noteworthy, forests are able to proliferate and endure, thanks a lot of interctions with microorganisms, invertebrates (like ants or bees, important pollinators). These are a few examples, why biological conservation, relies at the heart of our own population conservation.