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In “Nature Ecology & Evolution,” David Moreno Mateos presents new arguments on long-term ecosystem recovery

Clearing in a rainforest in Costa Rice surrounded by large trees

David Moreno Mateos, Assistant Professor of Landscape Architecture at the Harvard Graduate School of Design, has been published in Nature journal's Nature Ecology & Evolution, widely considered a leading journal in the field of ecology. Moreno Mateos's article, entitled “The long-term restoration of ecosystem complexity,” takes up future directions for the field of restoration ecology, arguing that long-term ecosystem restoration requires “moving beyond traditional biodiversity and functional assessments.” He positions interactions among species and their potential to evolve, rather than their sheer number, as fundamental factors in designing recovery strategies.

“Such a complex and long-term perspective is necessary to restore the temporal and spatial variation of communities and the feedbacks between species, their abundances, trait distributions, interactions and the deriving functions,” Moreno Mateos writes.

Photo of David Moreno Mateos
David Moreno Mateos

Moreno Mateos collaborated on the article with co-lead author Antton Alberdi, and with co-authors Elly Morriën, Wim H. van der Putten, Asun Rodríguez-Uña, and Daniel Montoya. As the team writes at the outset, the degradation to natural ecosystems caused by human activity has outpaced ecosystem-restoration efforts in recent decades, turning ecosystem recovery into “a global priority.” Hoping to advance restoration science in its efforts to help the environment, Moreno Mateos and colleagues unpack a series of research perspectives and trends across ecology and evolutionary biology, proposing more complex and elaborated frameworks that, they argue, may fuel more-constructive strategies on the ground.

“Once the knowledge proposed here is generated, next crucial steps are finding practical tools to implement this knowledge on the ground,” the team writes, “and integrating the knowledge in the additional layer of complexity existing in socio-ecological systems in which restoration happens.”

Among the traditional approaches the team takes up to reconsider and recharge are methods for measuring “ecosystem complexity,” or the amount of interactions among organisms (plants, animals, microbes, and otherwise) and among their respective life functions happening in a physical environment. In traditional approaches to measuring ecosystem complexity, species may be considered dots, and those dots are counted and studied—but the links and connections between them map not be.

Observing that, in terms of restoring ecosystems, the loss or gain of interactions between species, and not just the number of species, may be a better indicator of damage, or of recovery, Moreno Mateos and colleagues push toward new and more nuanced framework for cataloguing how “complex” a natural habitat or environment may be.

Other standard approaches to assess ecosystem recovery, the team observes, likewise tend to rely on simplified metrics or single functions—for instance, carbon accumulation in soils—and these simplifications can prove inadequate in advancing a deep understanding of “ecosystem complexity,” especially its effects on how species within ecosystems can or may adapt.

Moreno Mateos and colleagues observe an urgent need to understand how the potential of species to adapt to changing conditions may be an essential element when selecting particular plants to aid in ecosystem restoration. He and his co-authors argue that, given the rapidly lowering prices of genomics, a deeper understanding of the whole genome of species may soon be available, enabling ecologists to accurately find particular populations with the highest chances to adapt to restored and ever-changing environments. With caution, this approach may help guide decisions on introduction, or removal, of certain species to a given ecological system, in the interest of restoration.

Moreno Mateos also looks toward on-the-ground applications of his proposals. Their approach might begin with a look into a site's history and ecology, seeking species with “unusually strong roles on ecosystem structure, function and stability” – or “metacommunity hubs,” which may include trees, insects, birds, or other animals or organisms. Here, special research focus is paid to which species in a habitat contribute the most to or participate the most in networks of interspecies relationships. Such species, the authors observe, are the optimal fuel for generating and building upon ecosystem variation and complexity.

These “metacommunity hubs” trigger eco-evolutionary and co-evolutionary “cascades”, that is, facilitate the chances that other species also increase their chances to adapt to the new conditions existing in the restored site. These hubs will rapidly reshape patterns of interactions, abundances, and functional traits of the species used in restoration. The result, ideally, is a richer, more stable natural habitat, which in turn will have increasing value as climate change presents ongoing risks to environmental complexity.

“Increasing ecosystem complexity is important because it will likely increase the chances that restored ecosystems have the right features to adapt and evolve in a rapidly changing environment,” Moreno Mateos says. “This is crucially important today if we aim to address global restoration strategies, like the upcoming UN Decade of Ecosystem Restoration, that aims to reverse the dramatic loss of biodiversity and the immense benefits we need from nature.”