UNLOVED BUT VITAL
Life on Earth would be very different without this magnificent seven: our selection of important yet often overlooked groups of animals.
Though some species of midge are certainly troublesome to us, the enormous blooms that appear in spring and summer can energise entire food-chains. Many species of fish (which prey on the larvae) and birds such as swifts (which aerially filter-feed) depend on midges, which are also crucial pollinators. Without Forcipomyia midges there would be no chocolate – they are the only flies small enough to climb into the flowers of cacao plants.
It is estimated that the uppermost layer of soil is one of the most densely colonised animal habitats on Earth. Each square metre may be home to 250,000 soil mites occupying a host of niches. Oribatid mites (the most prolific) are important decomposers, eating dead plants, fungi and carrion.
There may be 200,000 of these cyanobacteria in every millilitre of seawater. Probably the most abundant form of life on the planet yet discovered as recently as 1986, these are primary producers in marine environments. The oxygen in one in every two breaths we take may be a result of their hard work.
Pound for pound, few creatures match dung beetles for economic value. One study suggests that the insects contribute $380 million each year to the American economy. By burying dung, they improve arable nutrient recycling and soil structure, as well as protecting livestock from invertebrate pests that congregate near mounds of dung.
Not only do these mammals provide crucial pollination services, but biologists are now beginning to understand that they also play a vital role in seed dispersal. By ingesting seeds that they transport and later defecate, fruit bats may also help plants to recolonise areas that humanity has destroyed. Some Old World species may carry them many hundreds of kilometres.
Ants are among the world’s earliest ecosystem engineers. By actively moving earth while nestbuilding, they serve as crucial mixers of the soil’s upper layers, much like earthworms. And they add value in other ways, too. By bringing scavenged insects and other invertebrates back to their nests, colonies of ants inadvertently raise the nutrient levels of the local soil.
Gnawing algae from rocks and coral with their large, beak-like teeth, parrotfish protect one of the most productive ecosystems on Earth from being overwhelmed. They also indirectly contribute to the tourism industry: parrotfish excretions produce the finest grains on the most idyllic white-sand beaches.
Parrotfish prevent coral reefs from being overwhelmed by algae, fruit bats disperse seeds and dung beetles return nutrients to the soil.