The Earth is in the midst of an extinction event. It’s the most significant extinction event following the conclusion of the Cretaceous. Popularly referred to as the “Sixth Extinction,” this time is defined by a decline in terrestrial biodiversity, a decline many attribute to humanity.
“For me, as a paleontologist, this is one of the really important issues of our day that makes us relevant, because we give context to what’s going on today,” Prof. Roy E. Plotnick, of the Univ. of Illinois at Chicago, told R&D Magazine.
Plotnick and colleagues from the Univ. of New Mexico and the National Museum of Natural History recently published research that states disappearing extant species may not leave behind a fossil record of their existence. The research was published in Ecology Letters.
Surprisingly, the researchers found that less than nine percent of threatened mammal species have a fossil record, and 20 percent of non-threatened mammal species have a fossil record. Additionally, only 3.3 percent of threatened bird species, and 1.6 percent of threatened reptile species boast fossil records.
Those species likely to fall into obscurity are the small, or those present only in a certain locale. Think of mice, Plotnick said. The critters are usually on the menu for a lot of predators. While their remains may show up in owl pellets, their leftover material is usually recycled back into the environment.
“It’s hard to preserve, especially in a terrestrial environment,” Plotnick said.
Generally, the recyclable nature of dead organisms is a good thing. If that weren’t the case, Plotnick said the world would be knee deep in the fossils of dead animals. Fossils are what fails to recycle, he said, attributing the dictum to his Smithsonian colleague Anna K. Behrensmeyer.
The researchers used a list of modern mammal species from The IUCN Red List of Threatened Species, and ecological databases of living species for their study.
Additionally, the researchers attempted to figure out how to compare the current extinction to the previous five. However, that proved difficult. While the current extinction episode is defined by a decline in terrestrial organisms, previous extinction calculations are heavily based on the fossil records left by hard-shelled marine invertebrates, according to Plotnick.
Regardless, the fossil record is far more durable than humanity’s records on digital storage devices. Plotnick said humanity’s longest lasting records are clay tablets. A fan of science fiction, Plotnick pointed to the post-apocalyptic genre as an example. If the digital record disappears in a catastrophe, all that will be left is the fossil record.
The researchers noted that future research will focus on how the modern extinction may appear in the future fossil record.
