You may not notice their good work, but small snail-like creatures known as limpets are performing an invaluable ecological service by eating and eating and eating. The herbivores’ consumption strengthens the resilience of an ecosystem in part by making space for other creatures, making it more diverse and resistant to the pressures of rising temperatures. “At first it might seem like an ecosystem untouched by consumers [herbivores and predators] is better, and, well, it would be better for populations of plants if that was all we cared about, but it’s not better for the ecosystem as a whole,” said Rebecca Kordas, zoologist and author of a new study that details the ecological benefits of limpets. “Consumers are important because they keep the populations of the species they eat in check. They keep them from taking over all of the resources.”
Kordas, whose work was recently published in the journal Science Advances, studied the positive impact of limpets by observing intertidal zones during the hot summer and checking the health of other creatures in that particular ecosystem. She found that starfish, anemones, mussels, barnacles and seaweed all did well when limpets were present; when they weren’t, the animal populations were not nearly as robust. “When limpets were part of the community, the effects of warming were less harsh,” said Kordas. Kordas and her team created mini-marine ecosystems on Salt Spring Island in British Columbia so as to study ecological changes in a more controlled environment.
The principle of consumers affecting available space in an ecosystem, and thus altering the biodiversity, can be seen on a macro scale as well. When wolves were reintroduced to Yellowstone National Park, for example, the elk population was curtailed, allowing smaller organisms to thrive where previously they had been affected by an outsized elk presence. Similarly, sea otters serve the purpose of controlling the sea urchin population in kelp forests, which protect coastlines from extreme weather and act as carbon sinks like forests on land. “The story is not about limpets, per se, but is more about preserving intact ecosystems and specifically, preserving consumers — herbivores and predators — in ecosystems,” said Kordas of her research’s broader implications.
“Intact ecosystems will be best equipped to resist the effects of a warming climate. Degraded ecosystems, where species have been removed, for example, because of harvesting or fishing, will not fare as well when they become stressed by rising temperatures.”
Via Popular Science