A regenerated forest can appear tall, vibrant, and verdant. Revitalized wetlands can be abuzz with insects and alive with birds. Yet, upon closer inspection, scientists have discovered that some of the tiniest inhabitants, such as certain mosses, lichens, algae, and fungi, are often absent.
Restoring ecosystems like forests and wetlands can aid in the conservation of declining animal and plant species and facilitate their recovery. However, recent studies indicate that not all species return at the same pace. Some of the smallest, least conspicuous residents may remain scarce or missing for decades, potentially impacting other species.
Ellen Macdonald, a botanist from the University of Alberta, has dedicated her career to studying forests, not just the trees themselves. She focuses on the minute flowers, mosses, liverworts, and lichens that thrive in the shadows of trees or on their bark’s textured surfaces.
According to Macdonald, the biodiversity of these smaller species far exceeds that of tree species. While to the casual observer, a regenerated forest may bear a resemblance to an untouched one, Macdonald has sensed subtle differences while walking through regrown coniferous boreal forests.
Macdonald combined her research with global data to analyze the recovery timelines of plants and animals in boreal forests following clear-cutting. The study, recently featured in the journal Nature Sustainability, revealed that birch and aspen forests and their inhabitants recovered within 25 years, whereas conifer forests took significantly longer. In conifer forests, understory plants, particularly lichens, mosses, and liverworts, took 85 years or more to reestablish, with some species still absent after a century.
The phenomenon of missing species is not confined to boreal forests. Researchers studying restored habitats like wetlands have observed apparent health alongside the absence of less visible species. German botanist Michael Melkonian recounted the restoration of wetlands near his village, where despite external appearances, the diversity of algae species he expected to find was notably diminished.
Viktoria Wagner, an associate professor at the University of Alberta, describes this decline as a “silent form of loss,” wherein species gradually disappear from their former habitats. Wagner’s research on “dark diversity” highlights the reduction in species diversity across various habitats worldwide.
The absence of certain species post-restoration can impede recovery processes and have far-reaching consequences. Algae, despite their small size, play a significant role in global oxygen availability and food production through photosynthesis.
Understanding these patterns can guide landscape managers in preserving a greater variety of species. Macdonald suggests that selective harvesting or partial cutting of conifer forests could be a more species-friendly approach.
Melkonian emphasizes the threat to algae habitats worldwide and the imperative to protect these species. His efforts to collect and preserve diverse algae strains aim to ensure the conservation of these vital organisms.
For Wagner, conserving biodiversity requires more than safeguarding isolated habitats; it necessitates maintaining and restoring sufficient habitat for species to thrive across landscapes. Active interventions are essential to counteract the ongoing loss of species diversity.
This series of articles sheds light on the work of scientists studying disappearing species groups, underscoring the importance of understanding their impact and preserving their presence.