Beetles come in all different shapes and sizes, and if you pay attention to the work at NCF you’ll notice that recently we have been very focused on two species of beetles in particular: The American burying beetle (ABB) and the southern pine beetle. These two beetles could not be more different, though both represent the great change that happens on Nantucket Island. While American burying beetles once would have been found on island, their population dwindled to extirpation until an initiative was started to found and bolster a population here on Nantucket. On the other end of the spectrum, Southern Pine Beetles were not found in great numbers on Nantucket until 2023 when we had our first outbreak of the beetle at the West Gate at Ram Pasture. These drastic changes in beetle populations are impactful in and of themselves, but they also represent greater environmental changes relating to human/nature interactions, habitat loss, and climate change.
The southern pine beetle’s significance to the northeast starts when it appeared in Long Island, NY in 2014. The beetles spread wide throughout the island and the state is still dealing with management issues today. Since then, the beetles slowly worked their way farther north. This was made possible by the warmer winter temperatures caused by climate change. Conservation organizations around Massachusetts knew it was only a matter of time before the beetles showed up in the state, so they set up pheromone traps around pine forests to track the beetles’ movements. On Nantucket we saw a slow rise in southern pine beetles over the years but nothing concerning until July 2023 when we found a full-on outbreak in one of our pitch pine forests. When surveyed it was found that around 20 trees had been affected by the outbreak and by the time the management was completed in September, over 200 trees had to be cut down.
Southern pine beetles are a tiny bark beetle, only about a third of the size of a grain of rice. Despite this, an infestation of many thousands can kill a full tree in a matter of weeks. The infestation starts off with a relatively small number of females who find a suitable tree. They then release a pheromone attracting more beetles to the tree where they then lay eggs. The larvae then hatch and all the beetles leave the tree once it has died to find another. Tree death is caused both by the boring and galleries created by the beetles and blue-stain fungus which is introduced along with the beetles. This process tears through forests if left unchecked.
The story of the southern pine beetle on Nantucket is one of learning to react and adapt to the changing conditions brought about by climate change. The arrival of the beetles in 2023 and the ensuing outbreak derailed many of the projects staff at NCF had been working on to focus on the immediate need to halt the infestation. As we worked on managing this outbreak, we also re-evaluated our prior forest management policies. In the past, many conservation organizations on Nantucket took a back-seat approach to forest management, electing to allow forests to grow as they will. In the case of West Gate this meant a severely crowded and unhealthy forest arose with a dense understory and little to no recruitment of new trees. Going forward, NCF and several other island land trusts have plans to more actively manage forests to give them a better chance of fighting off invaders like the southern pine beetle. Although the 2023 outbreak meant devastation for the West Gate stand of pitch pines, we can now use the knowledge we gained from the experience to inform our management practices across the island. And the wide cleared area has already been regrowing, with many baby pitch pines sprouting up across the landscape!
On the other end of the spectrum, both in size and concern, lies the American burying beetle. The ABB is the largest carrion beetle in North America, reaching 1-2 inches in length, and it is nature’s most efficient recycler. Carrion beetles find dead birds to lay their eggs, where the larvae will hatch after a few weeks and consume the carcass. American burying beetles are active from the late spring through early fall and then bury themselves in the ground to hibernate for the winter. Once found in 35 states in the US, their populations have now dwindled to only a few, and east of the Mississippi river are only found on Block Island and Nantucket.
The decline of the American burying beetle is due to several factors including loss of habitat, limited suitable carrion, competition with other scavengers, and artificial light pollution. While the American burying beetle is a generalist in terms of the habitat it can be found in, it is considered an “indicator species” which can alert researchers to poor ecosystem health. If these beetles are doing poorly, it is a sign that there is something out of balance in the habitat. ABBs require carrion weighing between 80 and 180 grams on which to rear young so a lack of suitable bird species can cause serious problems for the beetle population. Once highly abundant in the 19th century, passenger pigeons were hunted to extinction, which correlates with the major decline of American burying beetles. Now, far fewer suitable bird species can be found on Nantucket and those that do are also sought out by other scavenger species including rats, feral cats, and vultures. Nighttime lighting can also confuse the beetles and make them easier prey, and pesticides and herbicides can harm them directly as well.
Block Island houses the last known naturally occurring population in the east (monitored and managed by The Nature Conservancy) so in the early 1990s the US Fish and Wildlife Service and Roger Williams Park Zoo established a breeding program to bolster that population and create a reserve population here on Nantucket. This program has now released over 3000 beetles on Nantucket over 30 years and this summer was one of the best years to date. Led by Lou Perrotti from the Roger Williams Park Zoo and helped by volunteers from the Nantucket Land Bank, Linda Loring Nature Foundation, and Maria Mitchell Association, we released over 200 pairs of beetles in June and then caught 306 new beetles later in August! This was the highest capture rate in the whole history of the project on Nantucket! With the ultimate goal of creating a self-sustaining population on Nantucket, the project still has a lot more work to do, but these recent results give us a promising outlook on the future of this fascinating rare beetle.
One of the lesser talked about creatures, beetles are often forgotten about in discussions of global climate change and conservation initiatives. However, as can be seen by the two examples of southern pine beetles and American burying beetles, they can be incredibly important indications of localized and global change. Climate change will bring new species to areas unprepared for them or eliminate key species that are relied on for food or other ecosystem services. How we react to these changes will determine the impacts they have on our natural areas as well as on our own health and wellbeing. Adapting management practices to new situations and creating new conservation initiatives will be key in our changing world.
Written by Isaac Hersh, Environmental Educator