Nantucket is home to a remarkably high number of rare and endangered species. These plants and animals occur here for many of the same reasons that people find Nantucket so special­­–its undeveloped conservation lands and unique, windswept vegetation communities. Nantucket County has one of the highest concentrations of rare and endangered species in Massachusetts: of the 432 species listed under the Massachusetts Endangered Species Act, 89 species currently or historically occurred on the island. Read on to find out what has contributed to the rarity of these special and unique life forms, how they are protected, and why it is important that we share the island with them.

What is an endangered species?

An endangered species is a plant or animal that is in danger of becoming extinct in all or part of the area where it occurs. Each individual species is a unique organism that is different from all others in its genetic makeup. If a species becomes extinct, it is completely lost and can never be replaced.

Rare species are listed in three categories: Endangered, Threatened, and Species of Special Concern. Endangered species are in immediate danger of becoming extinct. Threatened species are rare, declining in number and likely to become endangered in the foreseeable future. Species of Special Concern are also declining in number and likely to become threatened should this trend continue. These designations are based on biological inventories conducted by scientists and researchers.

The chain-dotted geometer (Cingilia catenaria), a Species of Special Concern in Massachusetts, occurs in grasslands and heathlands on Nantucket (photo: Cheryl Beaton).

The Massachusetts Division of Fisheries and Wildlife maintains a regularly-updated list of Endangered, Threatened and Special Concern species protected under the Massachusetts Endangered Species Act. Currently, there are 10 fish, 4 amphibians, 16 reptiles, 30 birds, 14 mammals, 99 invertebrates (animals without backbones, such as insects and crustaceans) and 259 plants on this list.

On the Federal level, the U.S. Fish and Wildlife Service maintains a similar list with 715 animal and 942 plant species listed. The piping plover, North Atlantic right whale, northern long-eared bat, roseate tern and red knot are all examples of species protected under the U.S. Endangered Species Act that currently breed or otherwise utilize habitat on Nantucket or its surround waters.

New England blazing star (Liatris novae-angliae) is a Species of Special Concern in Massachusetts that requires open grassland habitats with full sun and nutrient poor, sandy soils (photo: Iris Clearwater).

Why do species become rare?

The earth is currently experiencing its sixth mass extinction crisis. E.O. Wilson, a renowned ecologist with Harvard University, has estimated that 3 species per hour (or 30,000 species per year) are being driven to extinction worldwide. Although species become rare and extinct for multiple reasons, almost all of them can be attributed to the direct or indirect actions of humans and their ever-expanding population growth:

Loss of Habitat. The alteration and destruction of habitat available to wildlife and plants is the single most common cause of rarity and extinction in the world today. Almost all of these losses can be attributed to human causes, including development, agricultural practices, deforestation, and their associated effects. In Massachusetts, coastal areas such as Nantucket have both high numbers of rare species and high rates of development. Many of these species have already been extirpated from other sites, leaving Nantucket as their sole refuge from habitat destruction. Fortunately, almost half of the island has been protected by the Foundation and other conservation organizations.

Barren’s buckmoth (Hemileuca maia) is a Species of Special Concern in Massachusetts that lays its eggs on scrub oak, an abundant shrub on Nantucket (photo: Iris Clearwater).

Hunting, Collecting or Accidental Killing. Unregulated hunting and over-harvesting have been the cause of many species’ declines. Colonial waterbirds such as terns, egrets and herons were collected in large numbers at the turn of the century for their feathers, which were used to decorate clothing and millinery. Hunting pressure was responsible for the global extinction of the passenger pigeon in the early 1900’s. Wild populations of showy plants species such as orchids have been over-collected. Whales were hunted to near extinction in the 1800’s for their oil and blubber; species such as the North Atlantic right whale are still imperiled by entanglement in fishing gear and garbage dumped at sea, despite protections from hunting.

Toxic Chemicals or Introduced Pathogens. Pesticides, herbicides and other chemicals introduced to the environment by humans have caused sickness and death to many species. The pesticide DDT became commercially available in the years following World War II. Its widespread use was responsible for directly killing thousands of songbirds, but its long-term effects on larger birds of prey such as falcons, eagles, hawks and osprey were not discovered until much later. DDT has been banned in this country since 1972, and birds of prey have made a remarkable comeback. More recently, populations of several species of bats, including the northern long-eared bat, have been decimated by White-nose Syndrome (WNS). The fungus that causes this disease, Psuedogymnoascus destructans, or Pd, was accidentally introduced to North America from Europe and has caused 90-99% population declines in some species.

Osprey (Pandion haliaetus) populations were once imperiled by eggshell thinning caused by DDT; they have made a remarkable comeback since the pesticide was banned in the U.S. and nesting poles were placed to encourage their comeback (photo: Jin Hong).

Other Causes of Rarity and Extinction. The development and alteration of natural habitats has impacted rare species in other, more indirect ways. Many non-native plants and animals have been introduced to North America and have out-competed native species. Domestic animals, such as dogs and cats, can wreak havoc on ground-nesting bird species. Natural predators, such as raccoons, skunks, crows and gulls can thrive in the presence of humans and wipe out populations of less abundant species.

Natural Causes. In some cases, population declines and subsequent extinction may be a natural process caused by sudden changes in climate, competition with other species or catastrophic events such as earthquakes and volcanoes. However, very few modern-day extinctions can be attributed to natural causes.

Why should we be concerned about the loss of rare species?

To many people, the importance of preventing a species from becoming extinct is not immediately obvious. In the preamble of the Endangered Species Act of 1973, Congress stated that endangered plants and animals “are of esthetic, ecological, educational, historical, recreational, and scientific value to the Nation and its people”. Although many of these species are small, not obvious or glamorous, and have no direct impact on our day-to-day lives, they are important parts of the environment we live in, and are protected for one or more of the following reasons:

Economic Value. Millions of dollars are spent annually in the U.S. on binoculars, spotting scopes, bird feeders, bird seed, admissions to national, state and private refuges, field guides, natural history tours and whale-watch cruises. The economy of pristine, relatively undeveloped places such as Nantucket is based on tourism. Undeveloped conservation lands, including the 9,009 acres owned by the Foundation, preserves the attractive qualities of such resort areas while also protecting habitat for rare species.

Eastern prickly pear (Opuntia humifusa) is an Endangered species in Massachusetts that occurs at the northern limit of its range on Nantucket (photo: NCF staff).

Useful Products. Many useful and economically important products are derived from native species. Among the most important are medicines; approximately 40% of the pharmaceutical products used today are derived from wild species of plants and animals. One of the major concerns regarding the extinction of plant and animal species is the yet-to-be discovered sources of medicinal compounds. The extinction of species today means that they will no longer be available for use and experimentation in the future.

Indicators of Environmental Quality. As mentioned previously, many species become rare because the habitat they require has either been destroyed or altered. The decline or loss of a species should be interpreted as an early warning signal that something is wrong with the environment that we all share.

Ecological Balance. Humans are many years away from fully understanding the intricate ecological processes that support life on earth. Every biological community, or ecosystem, is a complex web made up of plants, animals, and the physical environment they live in. Every species forms a strand in this web, and removal of one or more species weakens the entire system.

Piping plovers (Charadrius melodus) are rare, beach nesting shorebirds listed as Threatened under the U.S. Endangered Species Act (photo: Neil Foley).

What is being done on Nantucket to protect endangered species?

Rare species are protected in a variety of ways: through governmental legislation and through local efforts to protect, preserve and manage habitat and plan for future development. There are also many things that individuals can do to further the effort to protect endangered species.

Federal, State and Local Legislation. The U.S. Government and the Commonwealth of Massachusetts have both recognized the importance of preserving and protecting rare species through the passage of their respective endangered species acts. These pieces of legislation directly protect listed species from being harassed, harmed or killed and contain provisions for protecting the habitat that they need to exist. The Federal Endangered Species Act was described by Chief Justice Burger as being “the most comprehensive legislation for the preservation of endangered species ever enacted by any nation.” The Massachusetts Endangered Species Act is an additional tool that protects locally rare species that are part of the state’s natural heritage, despite the fact that they may be common elsewhere in the country. The Town of Nantucket’s Wetland Protection Act provides an additional level of protection for rare species that utilize the island’s wetlands and wetland buffer zones.

Sandplain blue-eyed grass (Sisyrinchium fuscatum) is another Species of Special Concern in Massachusetts that is strongly affiliated with open grassland habitats such as those found on Nantucket (photo: Danielle O’Dell).

Protection of Habitat. Since loss of habitat is the main cause of extinction, protection of habitat is the most effective means of protecting rare plants and wildlife. Efforts by conservation organizations such as the Foundation to protect habitat through direct acquisition are extremely important. Additionally, land can be protected through conservation restrictions as well as zoning designed to protect the unique ecological features of sensitive areas.

Habitat Management. Acquisition of habitat where rare species occur often needs to be accompanied by active land management programs. Open space attracts visitors that want to enjoy the beauty and tranquility of these areas. However, unmanaged use or overuse can result in disturbance of the rare plants and animals that live in these places. For example, rare beach-nesting shorebirds such as the piping plover, least tern and American oystercatcher need constant management when pedestrians and beach drivers are in their vicinity. Rare coastal heathland and sandplain grassland habitats on Nantucket were created by extensive, historic sheep grazing and now support numerous species of rare plants and wildlife. However, these areas are no longer grazed by sheep and are threatened by encroachment of woody shrubs. Active management such as mowing and brush cutting is needed to ensure the continued existence of these habitats and the rare species they support. 

Northern harriers (Circus hudsonius), formerly known as marsh hawks, are listed as Threatened in Massachusetts. Nantucket hosts the densest population of this species in the Commonwealth (photo: Vernon Laux).

Restrictions on Recreational Use in Sensitive Conservation Areas. The Foundation and other conservation entitiesplace restrictions on some types of recreational use in conservation areas to protect the rare and sensitive species. High levels of vehicle use in sensitive coastal areas can destroy sand dunes and the vegetation that stabilizes these systems, decreasing resilience to the impacts of climate change and sea level rise. Nantucket’s soils in general are extremely fragile: the passage of a single vehicle, horse or mountain bike over rare grassland and heathland vegetation destroys rare plants and leaves scars that persist for years. Such restrictions should be respected to ensure that these rare and endangered species and habitats will remain a part of our natural heritage for future generations to learn from, observe, and enjoy.

The Nantucket Conservation Foundation is a private, non-profit land trust that depends on contributions from our members to support our science projects, conservation property acquisitions and land management efforts. If you are not already a member, please join us now!