NASA-supported scientists have suggested an updated framework for the role of ferns in environmental recovery from disaster. Instead of competing with other organisms, ferns may act as facilitators that ease the way for other plants and animals to re-establish themselves in a damaged landscape.
The study examines how a biosphere recovers from major upheaval, be it from wildfires or asteroid impacts, using what scientists call a ‘facilitative’ framework (where the actions of organisms help each other) rather than the long-held ‘competition-based’ framework.
Ferns are a common type of vascular plant found in woodlands, gardens, and many a plant pot on apartment shelves. Unlike many other vascular plants, ferns do not flower or seed. Instead, they reproduce via spores. Ferns first appeared on Earth some 360 million years ago during the Devonian period and, prior to the evolution of flowering plants, were the most common vascular plant on Earth.
Ferns are often one of the first plants to re-establish in areas affected by large-scale upheaval events, and it has been suggested that this is because ferns produce spores in great amounts that are widely distributed on the wind. Some scientists, particularly in the fields of geology and paleontology, have used this ‘competitive’ success of ferns as a foundation for ecological theories about how recolonization happens after upheavals.
However, in recent years, growing research has shown that recovery is not only about competition. Positive interactions, known as facilitation, between ferns and other species also play a significant role. The authors of the recent study believe that it is time to re-examine positive interactions within ecosystems, rather than defaulting to a competition framework.
Ferns in History
“I love to imagine ecosystems through time and play a game in my head where I ask myself, ’if I could stand here for 1 million years, would this fossilize?’” said lead author Lauren Azevedo Schmidt of the University of California at Davis. “Because of the mental time gymnastics I do, my research questions follow the same pathway. How do I create synergy between modern and paleo research?”
The team examined ideas that have been developed based on observing modern organisms as well as ancient populations in the fossil record. They propose that, rather than out-competing other species, ferns act as facilitators for ecosystem recovery by stabilizing the ground, enhancing properties of the soil, and mediating competition between other organisms. This repositions ferns as facilitators of ecological recovery within disturbed habitats. This has broad implications for understanding how a community recovers and the importance of positive interactions following disturbance events. Because ferns are among the oldest lineages of plants on Earth and have experienced unimaginable climates and extinction events, they provide critical information to better understand the fossil record and Earth before humans.
“The Cretaceous – Paleogene [K-Pg] extinction event reworked Earth’s biosphere, resulting in approximately 75% of species going extinct, with up to 90% of plants going extinct,” said Azevedo Schmidt. “This magnitude of devastation is something humans (luckily) have never had to deal with, making it hard to even think about. But it is something we must consider when tackling research/issues surrounding exobiology.”
The longevity of ferns on Earth provides a view into the evolution of life on Earth, even through some of the planet’s most devastating disasters. This is of interest to astrobiology and exobiology because exploring how environmental factors can and have impacted the large-scale evolution of life on Earth through mass extinctions and mass radiation events can help us understand the potential for the origin, evolution and distribution for life elsewhere in the Universe.
Ferns in Space
In addition to their relevance to astrobiology, the resilience of ferns and their ability to help heal a damaged environment could also make them important partners for future human missions in space. NASA’s Space Biology program has supported experiments to study how plants adapt to space with the expectation that knowledge gained can lead to ways by which crops can be cultivated for fresh food. Lessons learned from studying resilient plants, such as ferns, could guide efforts to make crops adapt better to harsh space conditions so they can serve as a reliable food source as humans explore destinations beyond our planet. Previous studies have also looked at how plants might keep air clean in enclosed spaces like the International Space Station or in habitats on the Moon or Mars.
“Ferns were able to completely transform Earth’s biosphere following the devastation of the K-Pg [Cretaceous–Paleogene] extinction event. The environment experienced continental-scale fires, acid rain, and nuclear winter, but ferns were able to tolerate unbelievable stress and make their environment better,” says Azevedo Schmidt. “I think we can all learn something from the mighty ferns.”
The study, “Ferns as facilitators of community recovery following biotic upheaval,” was published in the journal BioScience [doi:10.1093/biosci/biae022]
For more information on NASA’s Astrobiology program, visit:
https://www.science.nasa.gov/astrobiology
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Karen Fox / Molly Wasser
Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
