In a new paper, scientists are calling for improved preservation of ancient rodent nests called middens and a renewal of research on these climate “time capsules.”
Ancient rodent nests—or middens—offer critical ecological and evolutionary archives of the last 50,000 years. Katie Becklin helps lead an effort for midden preservation and study.
Packrats, also known as woodrats, are the original hoarders, collecting materials from their environment to make their nests.
In deserts throughout western North America, for instance, packrat middens can preserve plants, insects, bones, and other specimens for more than 50,000 years, offering scientists a snapshot into the past.
Packrats and numerous other rodent species in dry environments around the world gather items into their nests from a radius of about 50 feet and urinate over them. The urine dries and crystallizes, hardening the fossils into rock-like masses and preserving the items inside.
Ancient rodent middens have allowed scientists to reconstruct the ecology and climate of semi-arid ecosystems in the Americas, Australia, Africa, and the Arabian Peninsula. These natural time capsules are unparalleled archives for observing how plant, animal, and microbial species and assemblages have responded over millennia as environmental conditions have changed.
Researchers have learned how climate change affected populations of plants and animals in the past, which can provide clues about how populations might respond to future rapid climate disruption.
Today, with advanced molecular technology, scientists can learn more than ever about the ancient organisms that once inhabited the area in and around these middens.
In the new paper, the scientists call for better protection of middens, new research in existing archives, and a revival of field studies. The paper appears in Trends in Ecology & Evolution.
The paper is the result of a multi-year effort involving collaborators from 10 different institutions in the United States, France, and Chile, according to Becklin, lead author and assistant professor of biology at Syracuse University.
“New technology in DNA and chemical analysis also allows us to get more information from smaller and smaller amounts of materials,” says Becklin. “We can start to understand what traits are important for predicting which species could do well in the future as climate change continues to impact natural systems.”
But most midden collections are stored at individual institutions where they could be lost or discarded as researchers retire. Midden fossils in the wild meanwhile are vulnerable to destruction by human development and ongoing climate change.
The authors recommend establishing regional depositories for midden materials, which could provide long-term access for researchers. Additional middens must be collected and preserved to stem accelerating losses from land-use conversion, mineral resource extraction, increased wildfire frequency, and climate change.
“This is an invitation to the next generation of scientists to take advantage of these resources, to build on the legacy of midden research so far,” says Becklin. “We need to protect these records and make them accessible to the global scientific community and bring in new ideas and people to continue this work.”
Source: John Tibbetts for Syracuse University
