Over a third of threatened or understudied oak tree species in Mesoamerica are not held in managed botanical collections anywhere in the world, and for many species, protection of their native habitats is lacking.

These are among the findings in a new Conservation Gap Analysis of Native Mesoamerican Oaks, published in English and Spanish, which was conducted by researchers at The Morton Arboretum. Researchers stress in the report being released during National Hispanic Heritage Month in the U.S. that it’s critically important to conserve these trees now before land-use conversion, climate change and other threats further alter their natural environments. Mesoamerica is the region extending from the U.S.-Mexico border through Panama.

Oaks are valuable keystone species that perform critical ecosystem functions and provide food and habitat for myriad animals.

“Mesoamerica is a global hotspot for oak biodiversity,” said report lead author Kate Good, the Arboretum’s global tree conservation research program manager. “In the face of climate change and habitat degradation, there is an urgent need to increase the number of Mesoamerican oaks in collections within their native country to help prevent further biodiversity loss.”

As of 2022, 22 species, or 37%, are not held in managed botanical collections anywhere in the world.

“We hope this report can help identify potential areas for collaboration and set conservation priorities, both in native habitats and managed botanical collections,” Good said.

The report focuses on 59 species in the region on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species assessed as either threatened or Data Deficient. The IUCN Red List is the globally recognized and standardized system for assessing the extinction risk of the world’s plant, animal and fungal species.

Climate change was identified as a threat for all 59 threatened or Data Deficient Mesoamerican oak species. Additionally, agriculture and residential or commercial development represented threats to 72% and 69% of the species, respectively.

Overall, the report indicates that 85% of the analyzed oak species are projected to see a decrease in the areas they are most commonly found under climate conditions predicted for the years 2061–2080. A decrease in a species’ preferred “life-zone area” does not necessarily mean it will no longer survive in the new environment, according to the report.

However, it does mean conservation activities are strongly needed to prevent potential biodiversity loss. Education, outreach, research and propagation or breeding programs were the most commonly cited priorities in the report for future conservation efforts.

The analysis also showed 16, or approximately one quarter, of the target species have less than 10% of their native range in protected areas. Among the 59 oaks analyzed for the report were the critically endangered Muller oak (Quercus mulleri), known to live in only two locations in Mexico; endangered Encino arroyero (Quercus brandegeei) native to southern Baja California Sur, Mexico; vulnerable oak species Quercus gulielmi-treleasei native to Costa Rica, Mexico and Panama; and data-deficient white oak Quercus deliquescens from Chihuahua, Mexico, to name a few.

“For many species, little is known regarding population size, distribution or threats,” said report co-author Silvia Alvarez-Clare, Ph.D., director of the Arboretum’s Global Tree Conservation Program. “This analysis helps to fill those knowledge gaps and is a crucial step toward facilitating partnerships and spurring conservation action to help protect threatened Mesoamerican oaks before time runs out.”

The report findings will be highlighted during the Arboretum’s National Hispanic Heritage Month programming.

Electric power companies dedicate significant resources to clearing overgrown plants and debris from the area surrounding power lines. These areas are known as electric rights-of-way, and anything that obstructs access to them can threaten power outages, hinder public safety and make it harder for utility crews to perform necessary maintenance and repairs.

A new paper shows that appropriate vegetation management is beneficial not only to utility companies but to pollinating insects as well. In the largest scale study of its kind, covering the greatest number of sites and species, researchers from the Florida Museum of Natural History have surveyed 18 rights-of-way managed by Duke Energy. They found that sites being maintained on schedule, which kept woody vegetation to a minimum, had a greater quantity and diversity of flowering plants and pollinating insects.

The research is published in the journal PLOS ONE.

“It’s a win-win,” said Chase Kimmel, insect conservation biologist at the museum and first author of the study. “It’s exciting that the goals of promoting pollinator habitats are in line with how Duke Energy would like to manage that land.”

Many of Florida’s insect pollinators thrive in early successional habitats, which are created by occasional disturbances, such as fire. Historically, the Florida landscape was a patchwork of different habitat types. As fields grew into forests, the resulting wood provided kindling for fires that ignited naturally, often from lightning strikes. The blaze cleared the understory and opened the canopy, allowing sunlight to reach the newly bare forest floor and creating the perfect environment for wildflowers.

Human development, however, has disrupted this cycle. Wildfires are quickly put out, and many areas are too close to homes and businesses for prescribed burns to be safely conducted.

“It’s getting rare to find early successional habitats,” said Ivone de Bem Oliveira, a postdoctoral researcher at the Florida Museum and co-author of the paper. “So, under the electric transmission lines, we can mimic that environment.”

Utility crews use mechanical and chemical interventions to maintain a safe corridor for energy transmission. Such maintenance activities can act as proxies for the wildfires that historically created successional habitats in Florida. This combination of management tools allows for easier, safer access to electric lines for repairs, improves transmission reliability, reduces long-term vegetation management costs and ensures safety for the habitat and energy consumer.

Methods include mowing, using selective herbicide applications to kill woody vegetation and using equipment to prune trees that get too tall or thick. This is particularly important in Florida, where weather events such as severe thunderstorms and hurricanes may briefly knock out power.

Although Duke Energy prefers to keep its rights-of-way free from coarse, woody debris, sites sometimes fall behind schedule. Curious about how this affected plant and insect diversity, the research team sorted their survey areas by classifying sites based upon measurements of bare ground and coarse, woody debris.

“In the higher intensity management locations, you could easily walk under the powerline, while at mid-intensity sites, one might find shrubs and various raspberry bushes, so you can’t walk in a straight line. In low-intensity sites, it’s hard to even get through the area,” Kimmel explained.

The researchers define the intensity of management not by how often the site is managed, but by what kind of habitat develops as a result. Some rights-of-way were considered high intensity while being managed only every year or two.

Across these sites, the researchers set a total of 2,376 pan traps to collect pollinating insects. These bowls, commonly used in insect diversity studies, are filled with soapy water and often come in bright blue, yellow and white colors. To insects, these colorful pan traps resemble flowers.

The researchers collected 11,361 flower-visiting insects in all, representing 33 families. Nearly half were bees, and a quarter were beetles. Flies, wasps, butterflies and moths made up most of the remainder.

Rights-of-way with high-intensity management had the highest abundance and diversity of these insects. These sites also had the greatest number and variety of flowering plants.

“In some of these environments, you often see a rich herbaceous understory because of regular disturbance,” said Jaret Daniels, senior author on the paper and curator at the museum’s McGuire Center for Lepidoptera and Biodiversity. “This also helps support rare plant communities.”

“The public might have a perception that a hands-off approach and letting nature do its thing is best,” Kimmel said. “But that’s not always the case.”

To support a rich and abundant pollinator community, the authors recommend high-intensity management in rights-of-way. This does not mean, as the name may suggest, constant mowing or indiscriminate herbicide applications, but a combination of strategies that target specific plants with the goal of maintaining a successional habitat.

Throughout much of North America, utility rights-of-way connect and bisect every type of landscape, from urban to rural. There are 180 million power lines in the U.S. alone and 5.5 million line-miles of land set aside for them. Using these areas as pollinator habitat could be a conservation game changer.

The long corridors can also help migrating species move more easily. They can help foraging insects travel large distances as they look for food, potentially bringing important pollination activity to neighboring conservation and agricultural lands.