A regenerated forest may appear tall, dense, and verdant, with revived wetlands abuzz with insects and teeming with birds. However, upon closer examination, scientists are discovering that some of the smallest inhabitants of these habitats, including specific mosses, lichens, algae, and fungi, are often still absent.
The restoration of ecosystems such as forests and wetlands can aid in the preservation of dwindling species of animals and plants, facilitating their recovery. Yet, recent studies reveal that not all species return at the same pace. Some of the tiniest, least conspicuous residents may remain scarce or missing for decades, 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 and on their bark.
According to Macdonald, the biodiversity of these smaller species far exceeds that of tree species. While to the layperson, a reforested area several decades post-logging may resemble an untouched forest with tall trees, birds, and insects, Macdonald notes a subtle sense of something amiss during her walks in regrown coniferous boreal forests.
Her research, combined with global data, delves into the duration required for plants and animals to reestablish in boreal forests post-clearcutting. The study, recently published in the journal Nature Sustainability, indicates that birch and aspen forests and their inhabitants recover within 25 years, whereas conifer forests take significantly longer. In conifer forests, understory plants, particularly lichens, mosses, and liverworts, may take 85 years or more to reappear and, in some instances, may not have fully recovered in a century’s worth of data.
This pattern of delayed recovery is not exclusive to boreal forests. Researchers studying restored wetlands and other habitats have observed that while these areas may seem healthy, some less visible species are still absent. This phenomenon of “dark diversity,” as described by Viktoria Wagner, refers to the silent loss of species from places they once inhabited, resulting in a reduction in species diversity at specific sites.
The absence of certain species can impede recovery and have unseen repercussions. Algae, for instance, play a crucial role in global photosynthesis, influencing oxygen availability and food sources on Earth. The decline in species diversity can disrupt ecosystems, affecting other species down the line.
Understanding these patterns can guide landscape managers on preserving biodiversity effectively. Macdonald suggests that selective or partial harvesting of conifer forests might be more beneficial than clearcutting, considering the slow recovery time of mosses, lichens, and understory plants.
In addition to forests, habitats for algae are also under threat worldwide, along with the species they support. Preserving biodiversity requires more than safeguarding isolated pockets of habitat; it necessitates the maintenance and restoration of adequate habitat across landscapes for species to thrive.
Efforts like Michael Melkonian’s, who meticulously collects and preserves various strains of algae, contribute to safeguarding species diversity. By establishing an “algal zoo” with over 5,000 strains, researchers aim to ensure the preservation of these species as living organisms.
The ongoing loss of species underscores the need for active interventions to uphold biodiversity. It is vital to protect and restore habitats to allow species to persist across landscapes, mitigating the continuous process of species loss.
This piece is part of a series highlighting the work of scientists focusing on disappearing species groups that often go unnoticed, emphasizing the importance of understanding their impact on our environment and exploring avenues to conserve them.