The American burying beetle ( Nicrophorus americanus), North America’s largest carrion beetle, is experiencing a resurgence in Nebraska’s Loess Canyons, marking the first regional population increase since the insect was listed under the Endangered Species Act in 1989. This remarkable comeback, hailed as a "holy grail" of conservation, signifies a positive shift for the prairie ecosystem, as these beetles serve as vital indicators of grassland health. Historically, the American burying beetle thrived across 35 states and three Canadian provinces, but habitat loss and dwindling wildlife populations have decimated their numbers, restricting them to small pockets in only 10 states.
The American burying beetle plays a crucial role in the ecosystem as a nature’s undertaker. These five-centimeter-long insects locate vertebrate carcasses, bury them, and embalm them with secreted fluids. This process preserves the carcass, providing a food source for the beetles and their larvae. The beetles are not particularly selective about the type of carcass they consume, feeding on anything from lizards and rats to birds. However, they require carcasses weighing between 100 and 200 grams, roughly the size of a small rabbit, to successfully raise their young. The decline of suitable carcasses, like the extinct passenger pigeon, prairie dogs, and bobwhites, alongside habitat loss due to agricultural expansion and tree encroachment, have contributed significantly to the beetle’s decline.
The resurgence of the American burying beetle in the Loess Canyons is attributed to a concerted effort by a coalition of over 100 private landowners, working in collaboration with government agencies and conservation organizations. This partnership has focused on reintroducing controlled burns to the prairie landscape, a practice historically crucial for maintaining grassland health. Since 2002, more than a third of the 130,000-hectare Loess Canyons landscape has been subjected to prescribed burns, successfully reducing eastern red cedar tree cover to near-historic levels in certain areas.
The positive impact of these restoration efforts was revealed through a study conducted by the Nebraska Game and Parks Commission from 2007 to 2019. Researchers baited traps with dead laboratory rats to monitor beetle populations across the Loess Canyons. Analysis of the collected data revealed a 17 percent increase in the total beetle population, rising from 168 to 196 beetles across all traps during the study period. Population modeling based on different land cover types within the Loess Canyons further confirmed the beetle’s preference for native grasslands free from eastern red cedar. The models predict a potential doubling of the beetle population if perennial grasses cover at least 75 percent of the Loess Canyons. Conversely, if tree cover exceeds approximately 10 trees per hectare or even a small percentage (0.1%) of native grasslands is converted to cropland, the beetle abundance plummets drastically.
The observed correlation between eastern red cedar encroachment and declining burying beetle populations aligns with previous research findings. Fire suppression has allowed the rapid spread of eastern red cedar, outcompeting native grasses and displacing wildlife, including the American burying beetle. Nebraska, in particular, is experiencing a significant loss of its grasslands, with approximately 2 percent annually succumbing to these encroaching trees. The Loess Canyons project demonstrates that actively managing and restoring native grasslands through prescribed burning can effectively reverse this trend and provide the necessary habitat for the burying beetle and other grassland species to thrive.
The success of the American burying beetle’s recovery in the Loess Canyons highlights the importance of collaborative conservation efforts. The commitment of private landowners, coupled with the support of government agencies and conservation organizations, has been instrumental in restoring the prairie ecosystem and bolstering wildlife populations. The reintroduction of fire has created a more diverse habitat, supporting a wider range of species, which in turn provides more food options for the burying beetles. This collaborative approach serves as a model for future conservation initiatives, demonstrating the potential for positive ecological change through community engagement and proactive land management.
