Many people, not just conservation-focused individuals, want to protect endangered species. For example, the giant panda has become an international symbol of wildlife conservation, representing the need for humanity to protect wildlife from our encroaching tendencies. Fewer people, however, know why preserving these species is important beyond simply our love for nature.
One primary way that biodiversity (or a lack thereof) affects us is through ecosystem productivity. It has been shown through a number of studies that biodiversity affects the productivity of ecosystems just as much as more “popular” metrics like herbivore population and soil composition. In a study looking at the ability of different savannah grasses to produce biomass, researchers have shown that increasing the species count from 4 to 16 was as influential as “removing a dominant herbivore, a major natural drought, and fire suppression.” So, biodiversity affects the ability of ecosystems to produce the resources that we need.
Secondly, there are many cases where we simply cannot know the implications of losing a particular niche of the ecosystem. For example, National Geographic Wild reported a few decades ago on a fishing community that advocated for less whaling restrictions, through the argument that killer whales of the area reduced fish populations, making it harder to catch fish. However, this backfired dramatically. As whale populations decreased, fully grown killer whales (which usually prey on younger whales of different species) turned towards seals, and then eventually towards otters, drastically reducing otter populations. The loss of otters allowed organisms such as sea urchins to flourish, which then were able to wreak havoc on the kelp forests of the sea floor. With the sea floor exposed, fish larvae and eggs were suddenly easy prey for any sea life that happened to be around, reducing fish populations much more dramatically than the whales could ever do.
In short, biodiversity isn’t just important to us because lions are majestic and elephants are impressive, but because of all of the different ways it affects us, both as a factor in what ecosystems can produce and through many other unforeseen consequences.