A regenerated forest can appear tall, verdant, and thriving. Revived wetlands can hum with insects and flutter with birds. However, upon closer inspection, scientists have observed that some of the tiniest residents, including specific mosses, lichens, algae, and fungi, are often still absent.
The restoration of ecosystems such as forests and wetlands can aid in the conservation of declining species of animals and plants and facilitate their population recovery. Yet, recent studies have revealed that not all species return at the same pace. Some of the smallest and least conspicuous inhabitants may remain scarce or missing for extended periods, potentially impacting other species.
Ellen Macdonald, a botanist at the University of Alberta, has dedicated her career to studying forests, focusing not on the trees themselves but on the minute flowers, mosses, liverworts, and lichens that thrive in their shadows, among their roots, or on their textured bark surfaces.
“There’s a significantly greater number of species in these areas than in tree species,” Macdonald emphasized.
To the casual observer, a regenerated forest several decades after logging may closely resemble an untouched one, brimming with tall trees, birds, and insects.
However, Macdonald recalled traversing regrown coniferous boreal forests and sensing a subtle discrepancy, even if she couldn’t pinpoint it immediately.
“To truly notice the absence, one would need to collect data,” she explained.
Macdonald conducted a comprehensive analysis by integrating her own research with global data to explore the duration for plants and animals to reestablish themselves as boreal forests regenerate following clear-cutting.
The research, recently featured in the journal Nature Sustainability, unveiled that birch and aspen forests and their inhabitants seemed to recover within 25 years, while conifer forests required significantly longer periods. In coniferous forests, understory plants, particularly lichens, mosses, and liverworts, took over 85 years to return, with some instances where they had not fully recovered within a century of available data.
‘They may not come back easily’
This trend is not exclusive to boreal forests. Researchers investigating wetlands and other restored habitats have also noticed that while areas may appear healthy, some less conspicuous species remain absent.
Years ago, CBC News interviewed German botanist Michael Melkonian regarding his research on how plants evolved to thrive on land. He described wetlands near his village in Jexmühle, southern Germany, brimming with carnivorous plants, sphagnum mosses, frogs, and dragonflies.
Although the bogs seemed visually appealing after being restored and replanted years after being drained for industrial purposes like logging, Melkonian discovered a stark absence of hundreds of desmid algae species he studies.
“The algae diversity was notably lacking,” he remarked.
