School Notes: School of the Environment
January/February 2026

The tiny threats facing the kings of the savanna

Lions are often celebrated as symbols of strength and resilience, but new research led by Yale School of the Environment scientists suggests that some of the most serious threats facing West Africa’s critically endangered lions are too small to be seen with the naked eye. A study published in Royal Society Open Science offers the first comprehensive look at the parasites living in West African lions, a subspecies that now occupies just 1.1 percent of its historic range.

“Parasites are truly the unappreciated majority, a grand puppeteer that regulates behavior, immune responses, and even biodiversity,” said lead author Nyeema Harris, the Knobloch Family Associate Professor of Wildlife and Land Conservation. “Some might think there is little left to learn from such an iconically charismatic and well-studied species, but there is a dearth of understanding of the parasite communities that plague African lion populations.”

A new road map for urban tree planting

When summer heat intensifies in cities, the consequences extend beyond discomfort; they affect public health, energy costs, and equity. A study coauthored by Yale School of the Environment research scientists offers a road map for making urban tree planting more strategic and equitable.

The study, published in Urban Forestry & Urban Greening, introduces a framework that could help cities decide where to plant new trees so they provide the most heat relief and other benefits to vulnerable communities. By pairing high-resolution heat data with demographic and land-use information, the team developed a prioritization tool that can guide city planners, nonprofits, and local governments in targeting the most impactful planting sites. 

“In practice the tool offers specific guidance of where to prioritize tree planting to reverse the trend of increasing urban heat, to have the greatest impact on the most vulnerable communities,” said coauthor Colleen Murphy-Dunning, executive director of the Hixon Center for Urban Sustainability and the Urban Resources Initiative.