Great Blue Heron at Halcyon Lake, early spring 2015. (All photographs courtesy of Mount Auburn Cemetery)
Mount Auburn Cemetery has served as a valuable habitat for wildlife since long before its founding in 1831, and conservation has been a concern for the Cemetery’s management as far back as 1870, when Mount Auburn’s Trustees established a Committee on Birds and inaugurated a program to plant trees and fruit-bearing shrubs that would attract birds. In the last two decades, with the increased awareness of Mount Auburn’s ecological uniqueness in the greater Boston area and the growing environmental sensitivity throughout society, more and more attention has been directed at managing the grounds as a natural resource and wildlife habitat. Mount Auburn today represents a tremendous natural resource, providing a diversity of plant and animal habitats containing food, water, shelter, and living space; in 2002 the cemetery was designated as one of the 79 Important Bird Areas (IBA) in Massachusetts by the Massachusetts Audubon Society. The landscape includes open parklike areas with large swaths of grass such as the area surrounding Willow Pond, woodland settings with significant understory vegetation, and wetland zones with opportunities for aquatic species. Mount Auburn’s three major water bodies—Halcyon Lake, Auburn Lake, and Willow Pond—attract a wide array of wildlife including birds, mammals, and amphibians. While past landscaping and horticultural design and management have created this naturalistic richness, there are opportunities to enhance existing habitat and create new types of habitat at the Cemetery. Our goal is to provide a wide diversity of vegetation offering nesting, protection, and food resources, in a manner that fits within our historic landscape preservation mission, does not conflict with our obligations to the families of those interred here, and will be sustainable long into the future.
In 1990, the Cemetery embarked on its first comprehensive planning process, resulting in 1993’s Master Plan. The horticultural directives that emerged from the Master Plan were to: maintain the then-current high level of plant species diversity; continue to plant trees and shrubs that support desirable wildlife populations; increase the amount of brushy, shrub undergrowth to diversify the canopy height and attract a greater variety of birds; maintain some less manicured areas consistent with Cemetery operations to allow for the natural senescence of woody plant material and serve as shelter for wildlife; maintain areas along pond edges for shrubs and small trees to serve as perching and feeding sites for birds; maintain areas of cover and open areas with emergent and other aquatic vegetation by ponds; and maintain the health of the vernal pool in Consecration Dell and the water quality of all other water bodies. These directives have grown in scope and emphasis in the Cemetery’s subsequent yearly planning and budgeting, particularly as we have recognized our importance as a unique oasis for migrating birds and a sanctuary for winter residents and summer breeding populations.
Much of Mount Auburn’s recent work on habitat enhancement has been made possible by funding from the Anthony J. & Mildred D. Ruggiero Memorial Trust established in 1994 to support wildlife habitat and educational programs at Mount Auburn. Through the generous support of the Trust (which funds 75% of a project) and the matching support of other foundations and individuals, Mount Auburn has been able to implement a number of major habitat enhancement projects. In December 2013, the Ruggiero Trust awarded the Friends of Mount Auburn Cemetery a grant of $92,000 to support the creation of a Wildlife Action Plan. With this funding, Mount Auburn brought together a “dream team” of ten professionals—landscape architects, environmental engineers, hydrologists, ecologists, ornithologists, and herpetologists— for a three-day workshop in June 2014. Represented organizations included the Massachusetts Audubon Society, Grassroots Wildlife Conservation, Halvorson Design Partnership, New England Environmental, Patrick Cullina Horticultural Design & Consulting, and Larry Weaner Landscape Associates, as well as independent experts. Each day included tours of different sites, group discussions, and one-on-one sessions. The range of discussion topics included the needs of specific types of wildlife for specific types of habitat, the impact of climate change on bird migration and habitats, the management of water quality in the ponds, and the aesthetic challenge of successful placement of naturalistic landscapes amid more formally designed ones in an active cemetery. The results of this workshop have generated a Wildlife Action Plan, in progress now, to guide our future efforts.
What follows below is a selection of areas where habitat management work has already been conducted and will be continued in the future. Each of these areas is important to one or more of Mount Auburn’s bird communities, from breeding species to spring migrants to fall migrants to winter residents to aquatic birds, and represents a variety of habitat resource types. Many birders are undoubtedly familiar with these areas, but may not be aware of their history. We also hope that as work proceeds under the Wildlife Action Plan, this article will help explain some of what birders might see on the grounds in the future. Every effort will be made to minimize impacts on birds and other wildlife, but some disruption may be inevitable for human visitors.
In 1998, Auburn Lake (also known as Spectacle Pond by many) was the first of Mount Auburn’s three ponds to be dredged to improve its health and habitat value, as well as its aesthetics. Over the decades since the creation of the pond in the 1850s, organic matter and sediment had accumulated to the point where Auburn Lake was only about two feet deep in its center and appeared to be largely mudflats during summer drought periods. Working with the direction and support of the Watertown Conservation Commission, the water was drained through a carefully designed filtration system into the Charles River, and a backhoe with a 70-foot reach was used to remove several feet of sediment. A number of shallow emergent zones were left along the pond’s perimeter and planted with wetland species such as bulrushes, sweet flag, and pickerelweed, to provide habitat for a broader diversity of wildlife. In addition, five large Norway maple trees were removed from the steep slope around the north basin and a new understory of native shrubs and groundcovers was planted. A mated pair of Wood Ducks took up residence in Auburn Lake during the first spring after dredging and planting, and since then Green Herons, Great Blue Herons, and many other species of birds, turtles, and amphibians have enjoyed the improved habitat over the years.
Although conditions are vastly improved at Auburn Lake, they can be made better. The northern end of the lake, near the Gardner Mausoleum, is lacking in aquatic vegetation. Mount Auburn plans to install a biofiltration aquatic plant shelf, which will provide the three benefits of filtering storm water before it enters Auburn Lake, adding habitat biodiversity, and improving the aesthetic appearance of the area. During the course of the Wildlife Action Plan charrette, the bird specialists on the team observed that Mount Auburn currently does not include any running water features. Birds, especially migrants, are attracted to the sound of running water, so a running water feature would be of great benefit to birds and the birders who could rely on finding birds there. The steep slope and natural storm water drainage patterns at the northern end of Auburn Lake create an ideal location for the development of a constructed mountain stream. A recirculating pump will ensure consistent flow, and a pedestrian bridge in the current roadway will provide excellent observation opportunities.
Planting of native species after removal of non-native species around a hillside tomb on the western slope of Consecration Dell, 1998.
Consecration Dell, same hillside tomb as previous photo, 2011.
Unlike the rest of the Cemetery, where intensive horticultural management has maintained the landscape over the decades, the 4.2 acres of Consecration Dell’s natural valley had been minimally managed from the 1890s until 1997. During this time, invasive Norway maple had become co-dominant with the native red oak in the forest canopy. In woodlands where these maples become established, there is a conspicuous absence of understory vegetation. This condition further complicated matters in the Dell, where the steepness of its slopes had led to severe soil erosion problems. Work to restore the Dell to a more natural state began in 1997 with the planting of native species along the banks of the pool. The Dell was—and is—ecologically significant in part because of its resident population of spotted salamanders, one of the few in eastern Massachusetts. Our goal was to enhance the area aesthetically while also respecting the habitat requirements of the salamanders, which breed each spring in the vernal pool. The spotted salamander population has been carefully monitored each year, and it has been gratifying to note its overall success.
Since 1997, we have gradually expanded our woodland restoration efforts onto the slopes surrounding the pool, planting native New England species of trees, shrubs, ferns, and other groundcovers. With each phase of the woodland restoration, the first step has been to remove the Norway maples and other non-native species, such as Japanese yews and Japanese barberries, and replace them with native species ranging from sassafras and striped maple to mountain laurel, Christmas fern, and Solomon’s seal. In 2003, several hundred seedlings of Norway maple, along with a number of mature trees, were removed from the southern slopes of the Dell. Over 400 new trees and shrubs were installed on the slopes where the invasive trees were removed, and more than 3,400 herbaceous plantings created carpets of ferns and woodland wildflowers, which are lush and vibrant today. As all of these plantings have matured, including many that provide nuts, seeds and fruits that are attractive to a wide variety of birds and to the insects that birds feed upon, the rebuilt understory vegetation has provided shelter and nesting materials. Visitors also may have noticed that unlike most other areas of the Cemetery, deadwood, whether standing or fallen, is allowed to remain in place as much as possible to provide additional food and shelter resources. Not only is this important for a wide variety of birds and invertebrates, but this practice is also aesthetically harmonious with the naturalistic woodland character of the Dell.
Our overall objective has been to make Consecration Dell a better natural habitat for birds and an ecologically sound plant community that will be sustainable long into the future, and we feel secure that we have made great strides toward reaching that goal. Future work will include additional plantings on the highest slopes of the Dell, to stabilize the soil in that area and to extend the prime habitat further upslope. In the course of this work we will improve the condition of the rustic walking paths that traverse the steep slopes. This will be a welcome improvement for some visitors who have avoided the paths out of safety concerns for exposed roots and washed out paving material.
Aquatic plants being installed at Willow Pond’s emergent shelf, 2005.
Emergent shelf at Willow Pond, 2015.
Throughout most of the Cemetery’s history, the area around Halcyon Lake had an open, formal character, which included large expanses of turf running to the water’s edge. In spring of 1999, several large native trees (oaks and tupelos) and small ornamentals (dogwoods and crab apples) were planted around the lake. The invasive yellow iris along the entire lake edge was taken out, and hydraulic dredging to clear out decades of muck was done in summer 1999. Since then, a filtration system has kept algae and scum at bay, and plantings along the eastern edge of the lake have matured into an aquatic shelf providing useful habitat for birds and amphibians. However there is a lot of room for improvement, and future plans include more intensive invasive species control, replanting of the aquatic shelf, a new biofiltration system to further improve water quality, and, potentially, the addition of a floating island which would add places to hide for small fish and amphibians as well as safe resting sites for turtles and water birds.
Narcissus Path and Beech Avenue Wildlife Corridor
In an effort to provide continuity between habitat zones, the Narcissus Path and Beech Avenue wildlife corridor was the first step in knitting together a series of wildlife refuges that have historically been somewhat segregated. Its southern end lies only 350 feet from the entrance to Consecration Dell. At its northern end lies Indian Ridge, a long (one third of a mile) stretch of semi-wild landscape that also has been targeted for habitat replanting in the future. In the angle between these two ridges lies Auburn Lake, with its nearly five-acre basin of diverse wildlife habitat. More than 3,900 plants, including several new varieties of hollies, were installed in an area covering about one acre. The plant list was chosen with the primary objective of offering food resources and protective cover to birds, butterflies and other insects, and many small animals. This project was completed in 2013, with ongoing maintenance.
Wildflower Meadow at Washington Tower
The wildflower meadow at Washington Tower represents a plant community that has become scarce in Massachusetts due to development, fragmentation of farmland, pollution, and competition from invasive plants. Created in 2007 with the installation of almost 10,000 grasses, herbaceous perennials, and shrubs, the meadow benefits many species of butterflies, insects, and small mammals and also contains a seep, a small water feature that is attractive to these animals. Although it is not a large enough habitat to benefit grassland birds, it offers food sources to many other species, including hummingbirds. The wildflower meadow has been quite successful and will need only refinements of the plant species present and some renovation of the seep into a more attractive feature.
In 2004-2005, the Cemetery completed the installation of a butterfly garden and a wetland emergent zone habitat at Willow Pond. A hydro-rake was used to remove invasive aquatic weeds and accumulated organic debris from the bottom of the pond. A shallow underwater shelf with aquatic plantings was then constructed to provide wildlife habitat and also to act as a biofiltration system at the point where significant water and sediment flow into the pond during major rain events. As at Halcyon Lake and Auburn Lake, these efforts did result in increased habitat for birds, fish, amphibians and invertebrates, but some significant types of habitat were absent throughout most of the pond, particularly cover for tadpoles and frogs. An added complication came in the fall of 2014, when heavy rains caused flooding in our storm water drainage system that washed away much of Willow Pond’s biofiltration system. Visitors may have noticed that the traditional turtle basking area at the north end of the pond has vanished, a casualty of the flooding. We will take advantage of this opportunity to rebuild a more extensive aquatic shelf with a viewing platform for visitors, and will also investigate adding floating islands to the main body of the pond. In addition to adding habitat resources, the vegetation on floating islands helps improve water quality as the root system filters nutrients out of the water.
These areas represent the major, highly visible projects at Mount Auburn over the past couple of decades, but there have been and will continue to be other, less immediately obvious habitat enhancement projects throughout the Cemetery. One substantial challenge we face is that one of the most valuable habitats for the breeding bird populations of Massachusetts is shrubland, characterized by multiple dense layers of woody vegetation from ground level to up to twenty feet high. Shrublands are by their nature ephemeral, typically occurring as transitional or early successional habitat following some disturbance to an area and preceding the establishment of woodland, and the general populace sees them as unkempt or unmanaged landscapes. While we are able to maintain some areas of the Cemetery in a naturalistic state, such as Consecration Dell, we have a responsibility to our clients and their families and to our mission of preservation of the historic landscape that constrains us from letting nature take its course throughout the grounds. However, we are exploring the possibility of creating managed shrublands with a mix of flowering and fruiting plant species that would mimic the structure of a shrubland, even if it does not mirror the typical species found in a natural Massachusetts shrubland.
Other future areas for improvement include Alice’s Fountain, a small water feature constructed in the 1860s in an area that had been wet bog and is now a naturalistic pool with a drip fountain feature. The pool could be expanded into a larger vernal pool for additional salamander habitat and provide an important connector between Consecration Dell and Willow Pond, while also helping with our storm water management. And we will also be watching climate change closely, adjusting our plant species selections throughout the Cemetery in order to ensure that there will be food availability for long-distance migrants when they arrive in profound need of sustenance.
Mount Auburn has a long and illustrious history in the birding community, and we are looking forward to continuing that relationship in our collaboration with Mass Audubon now and in future Citizen Science projects that will help collect and disseminate data on the abundance and distribution of birds throughout the year. Please stop by the Visitors Center or check our website (www.mountauburn.org) regularly for updates on all of these projects as well as our future initiatives.
Dave Barnett is President & CEO of Mount Auburn Cemetery, and Regina Harrison is Executive Assistant at Mount Auburn Cemetery and an Associate Editor of Bird Observer.