MSU researchers bring new approach to stopping the biodiversity crisis

What if saving one animal species from extinction at a time isn’t the most effective approach? Michael Belitz, a Michigan State University postdoctoral researcher in the Zipkin Quantitative Ecology Lab, asked himself that question during his graduate work protecting a single butterfly species.

As he studied species-level conservation, he found himself thinking about how multiple species interact and how they responded to warming temperatures, extreme weather and urbanization. He wondered if he might find more success protecting multiple species in a habitat instead of focusing on just one. 

Now, Belitz has coined a term for this work: assemblage-level conservation. In a newly published perspective article in Nature Reviews Biodiversity, Belitz and his colleagues advocate for the conscious protection of multiple species at the same time. They argue that conservation targeting groups of related species is an effective way to quantify, predict and manage multiple species. The time is right for a perspective shift, they argue, not only by researchers, but also by land managers, policymakers and conservationists. 

“We are excited to have this perspective piece published in one of the first issues of the journal Nature Reviews Biodiversity,” Belitz said. “My hope is that by defining and coining ‘assemblage-level conservation,’ funds and efforts can be more targeted and streamlined.”

Interdisciplinary collaboration between biology, modeling and natural resource management has opened the door to studying the many complex challenges related to biodiversity loss. Computational power, advances in statistical modeling and increased data availability make assemblage-level conservation possible.

At the forefront of assemblage-level data analysis, the Zipkin lab uses statistical analyses to simultaneously model many species from animal communities, providing a holistic understanding of biodiversity and the causes of biodiversity declines. With this approach, Belitz and his colleagues can include more species at larger scales, leading to better estimates for less studied and rare species. The lab also works with land managers and conservation professionals to produce conservation-relevant outcomes from their models.

“Assemblage-level analyses provide us with an opportunity to evaluate how, where and why individual species and whole communities are declining,” said Elise Zipkin, Red Cedar Distinguished Professor at MSU and senior author on the paper. “It also provides us with new opportunities to implement strategic conservation actions in a time of accelerated biodiversity loss.”

In the perspective article, the authors explain some of the advantages of assemblage-level conservation over two other common conservation methods: species-level conservation and ecosystem-level conservation. 

A species-by-species approach is the most common, but it can be biased toward the conservation of charismatic and large species. This approach also can’t address the full problem in areas where many species are in decline. 

Take the example of a flagship species of insect decline — the monarch butterfly. At the species-level, the intervention of planting milkweed has helped monarch populations. However, an assemblage-level approach such as planting a diverse mix of both host and nectar plants for native pollinators has been linked to increased overall pollinator diversity and abundance, while also resulting in more monarchs.

On the other end of the spectrum is ecosystem-level conservation, which aims to protect the physical environment and the services provided within a targeted geographic area. Ecosystem-level conservation is complex and can be hard to manage, especially at regional scales and over long periods of time. Rare and endangered species may be overlooked, and it does not always prioritize biodiversity declines. 

That’s where assemblage-level conservation comes in. Management actions that seek to preserve both the number of species in an area and their abundance can benefit both individual species and ecosystem services. One of the Zipkin lab’s ongoing projects is studying the assemblage of butterflies across Midwestern states. Their goal is to figure out how both individual species and the butterfly community as a whole are changing in an effort to prioritize conservation efforts. This collaboration with the U.S. Fish and Wildlife Service and the U.S. Geological Survey will determine what, if any, changes would protect the greatest number of species.

“When thinking about the total number of species that are declining, it sometimes feels that the conservation challenges are insurmountable. Focusing on manageable segments can help keep us moving forward,” Zipkin said. “Our hope is that a shift in perspective to focus on assemblage-level conservation will open up new opportunities to protect biodiversity and mitigate the declines of whole taxonomic groups, such as butterflies.”