How Oft-Ignored Snails are Vital for Life on Earth
The tiny, slimy organisms are crucial to life on the planet yet are threatened with extinction
When we talk about wildlife conservation, we often forget that there are countless tiny organisms that play as crucial a role as an elephant, a tiger, or an eagle. We want to protect the majestic animals by channeling a significant amount of funds to their research and preservation and turn a blind eye to species that are not visually attractive or not something that we’d want as a pet. Snails and other gastropods fall in the latter category.
Some may find some snail shells attractive and a few find snails fascinating but many perceive them as repulsive, slimy, and slithery creatures and give no thought to their importance in ecosystems or to the fact that they are rapidly becoming extinct.
Gastropods are the most species-diverse group in the phylum Mollusca. Estimates range from about 40,000 to 100,000 gastropods, making Mollusca the most species diverse phylum on this planet after Arthropods, most of which are insects. However, worldwide, a few scientists are engaged in the field of malacology, which is the study of mollusks.
In 2019, the last known individual of Achatinella apexfulva, a Hawaiian tree snail, George died. His passing did create a buzz of media coverage, but the attention to the plight of the world’s endangered snails was short-lived. The tiny, slimy snails contribute in a big way to ecosystems yet many of the snail and slug species are threatened with extinction.
Snails: Oft-forgotten Species in Conservation
While conservationists are striving to prevent iconic species such as killer whales and grizzly bears from going extinct, over one thousand mollusk species are recognized to be either endangered or critically endangered and still do not get the number of conservation funds or efforts they require. For the vast majority of tropical snails, there is no data on their extinction risk and a large number have not even been discovered and described. Many will have gone extinct before we were even aware of their existence.
In a conversation with Planet Custodian, British malacologist, Fred Naggs pressed upon the importance of invertebrates, the animal group that includes mollusks. He said;
Many invertebrates act at the second trophic level and as a food source for numerous other animals such as many species of birds, reptiles, amphibians and small mammals. If invertebrates disappear, so will all these other organisms that are dependent on them for food. But invertebrates also have numerous other roles to play in the ecosystem. Insects, of course, play a key role in pollinating plants and, many snails are detritivores, contributing to the recycling of nutrients.
A former employee of the Natural History Museum, London, Fred has been working in the field for over four decades. He has studied snails in several countries including India, Sri Lanka, Nepal, Thailand, and Vietnam.
After decades of neglect, there has been a welcome resurgence of interest in snails but there is a lot of catching up to do. In addition to recording the plight of snails through their high extinction rates, it must not be forgotten that snails, semi-slugs, and slugs are vital players in the forest decomposition process and recycling of nutrients to the soil through their decaying bodies, shells and feces.
He also mentioned that, unlike many insects, snails can’t run or fly away. Therefore, with changes in climate and habitat fragmentation, they cannot escape from isolated pockets of natural habitat that are surrounded by human-transformed land, which affects their numbers tremendously, driving them to
large scale extinctions..
Along with his peers, he recently published a paper titled: William Benson and the golden age of malacology in British India. William Benson was a civil servant in British India and an amateur malacologist. The historical paper widely discusses the large collections of mollusks he collected and described from India. Even though an amateur, Benson’s work paved the way for the field in the country; however, after the early years of the twentieth century, many years elapsed in which little progress was made.
In Canada, 640 species are listed under Canada’s Species at Risk Act. Over a third of threatened species are plants, mosses and lichens, while 30 percent consists of mollusks and reptiles. People, including conservationists, sometimes forget the importance and the fact that every life has a purpose to serve.
There are over 750 known species on the Hawaiian Islands. Unfortunately, humankind’s ignorance has led to the extinction of two-thirds of those species, while 50 are endangered. But what purpose do snails have in the health of the ecosystem?
How Snails are Important for the Ecosystems?
Snails are important environmental markers and biodiversity interpreters and can help monitor climate change. Land snails help recycle forest nutrients and are food for a variety of vertebrate animals and invertebrates. Post their life, dead shells can form an important source of calcium for other animals in calcium-poor habitats. All these contributions advocate making snail conservation a high priority.
Snail help in the decomposition of natural material into smaller parts and as such help to uphold nature’s cycle. Some snail species are carnivorous, which helps manage prey populations. Their shells also become homes to other species after they die.
If we fail to help conserve snail populations, numerous natural relationships and processes would collapse. It has already begun around the world. For instance, the Hawaiian snail Achantinella fuscobasis is critically endangered and Alabama’s Leptoxis compacta’s habitat has shrunk to an alarming size.