Efforts to increase plant biodiversity throughout Mount Auburn’s 175 acres began in the 1990s to address Master Plan (1993) recommendations. Initially, our diversification efforts responded to the evident lack of ground-layer and understory vegetation. Over the past 20 years, however, these efforts have become more focused through our strategic planning. Now, diversifying the Cemetery’s plant collections is an essential strategy to preserve our landscape’s health and increase its resiliency in the face of climate change.
According to our most recent Plant Collections Analysis, the statistical data shows a robust botanical collection that has been steadily increasing in numbers and diversity. An overview of the collections is below.
The plant collections reflect the dynamic nature of Mount Auburn’s landscape. Every year we suffer plant losses due primarily to environmental stresses (e.g., drought and severe storms), and we add new plantings to the grounds. This net gain/loss of plants measures our ability to respond to changing conditions and build resilience through continuous diversification. The number of tree removals and new tree plantings remains relatively static, not only for the most recent five-year period but over the past 20 years. However, we plant significantly more shrubs and groundcovers in a given year than we remove.
In 2009, our total number of plants and massed plantings was 16,772, and the number of different taxa was 1,754. Over the subsequent 10-year period, the total number of taxa increased by 33% to 2,335. We plan to continue this trend toward diversification in the next few years with several landscape enhancement projects, including the Indian Ridge Path Restoration and a proposed shrubland-meadow along Chestnut Avenue. With both projects, we will introduce new taxa that meet our biodiversity goals. However, it might be unrealistic to expect another 33% increase in new taxa over the next 10-year period. The more diversified the collections become, the harder it becomes to continue their diversification. Therefore, it might be more prudent to monitor these new additions and then add more of what is most successful.
The following initiatives have been driving our diversification efforts for the past several years and will continue to do so for the foreseeable future.
▸ Conifer Collection Diversification
Since the early 1990s, we have worked strategically to reduce our hemlock collection which then represented a significant percentage of the Cemetery’s coniferous plants. Hemlock removals started as a response to the Hemlock Woolly Adelgid, an outbreak exacerbated by climate change. Today’s collection of 125 hemlock trees is one-third of what it was three decades ago, and the introduction of additional conifer species has diversified the collections. To add new conifer taxa to the collection, we expanded our in-house plant production program. But the process is slow because we have to propagate most of these plants from seed or cuttings. There are currently 250 seedlings in production, though we anticipate using only a portion of these once they reach maturity.
▸ Underground Tomb, Curb, and Fence Lot Plantings
There are 640 lots on the grounds where granite curbing, iron fencing, or underground tombs present challenges for the safety of structures and staff performing routine turf maintenance. Our efforts to replace the turf in these lots with more sustainable and low-maintenance plantings started in 1993. Currently, we have completed 244 of these conversions (38%), and in recent years have averaged five new conversions per year.
▸ USDA Hardiness Zone 6 Plant Introductions
This is a long-term initiative, which anticipates further warming and growing conditions different from most of what Mount Auburn’s landscape has seen in the 190 years since its founding. After testing a fair amount of Zone 6 taxa, we will focus on adding the more proven ones into our landscape.
▸ Late Spring and Summer Flowering Plant Introductions
This initiative is primarily a response to the earlier and earlier flowering times we are seeing in our plants each spring, a phenomenon documented by our citizen scientist phenology study. This earlier bloom creates insect (food) shortages for birds during the annual spring migration. In the past two years, 50% of new plantings represent later-flowering species, and this initiative should continue for the foreseeable future.
▸ Historic Landscape Character Zone Enhancements
In place since 1993, this is by far the broadest and most complex initiative. Our desire to preserve the historic landscape initially drove much of the work supporting this initiative, but it turns out that historically appropriate practices are also more sustainable. For example, to introduce a more naturalistic appearance in the Cemetery’s historic core, we replaced traditional turf with lower-maintenance (minimally mowed) turf and groundcovers. In other parts of the Cemetery, we have transitioned high-maintenance shrubs to lower-maintenance alternatives. Towards this goal, we have replaced nearly 90% of the hedges in “the Meadow” area (near the Greenhouse) with lower maintenance plantings. In addition, we’ve used the renovations at Harvard Hill, the Appleton lot, the North Dell Meadows, the Beech-Central historic zone, the apiary meadow, and the slopes along Mountain Ave to introduce turf alternatives. Looking ahead, the final phase of our Indian Ridge Restoration project will see turf replaced with a sedge-wildflower meadow, and a proposed project along Chestnut Avenue will convert nearly 4 acres of turf to a shrubland-meadow.
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If we genuinely care about future generations, we must act now to protect planet Earth. The effects of climate change are clear, and it will take all working together to reduce the devastating damage happening here at home and around the globe. It is time for bold action!
Mount Auburn took a new bold step in June 2021 with the formal adoption by the Board of Trustees of a Climate Action and Sustainability Plan. The ambitious goals outlined in this new Plan aim to make the Cemetery carbon neutral by the year 2050 while also addressing broader environmental, social, and economic concerns. The Plan builds upon decades of ecologically sensitive best practices to further reduce the impacts of Mount Auburn’s landscape maintenance, burial, and cremation activities. The Plan also outlines goals to create a resilient and healthy ecosystem that benefits Mount Auburn’s flora and fauna while ensuring that all staff and visitors are valued, respected, and engaged. Lastly, the Plan makes an institutional commitment to align our financial investments with our values and the environmental and social stances we support. Ultimately, this Plan is about reducing what we take while increasing what we give back to the planet and the community.
The formal adoption of a Climate Action and Sustainability Plan marks the achievement of a significant milestone in Mount Auburn’s broader 18-Month Strategic Bridge Plan. With initiatives organized into three themes – Openness & Welcome, Beauty & Serenity, and Stewardship & Sustainability – the Bridge Plan will strengthen Mount Auburn’s core mission and build a foundation to support its future aspirations.
Mount Auburn’s Climate Action and Sustainability Plan’s ambitious goals address environmental, social, and economic concerns. With the goals and strategies outlined in the Plan, we will:
▸ Achieve carbon neutrality by 2050.
▸ Build resilience to environmental stress by increasing the biodiversity of Mount Auburn’s plant collections.
▸ Create healthy conditions for urban wildlife.
▸ Connect the community with Mount Auburn’s landscape through thoughtful educational programming and increased volunteer opportunities.
▸ Inspire individuals, peer organizations, and communities to be sustainable by sharing our knowledge and celebrating our successes.
Mount Auburn’s 175 acres provide food, water, cover, and nesting sites for a diverse community of urban wildlife. Predators and prey are well-represented at the Cemetery, allowing the food web to follow its dynamic seasonal cycle. Guided by a Wildlife Action Plan (2015), Mount Auburn protects and enhances the value of this urban ecosystem and invites a community of researchers and educators to use the Cemetery as a living laboratory for the study of biodiversity.
The Fauna of Mount Auburn
It may be best known as a place where migratory birds take temporary cover each spring and fall, but the Cemetery is also home to many resident bird species. Screech owls make use of tree cavities, great blue herons hunt in the shallow emergent zones at each of our ponds, while red-tailed hawks captain the sky and snatch up small mammals from the grounds for nourishment. Mammals residing at Mount Auburn include Eastern cottontails, gray squirrels, chipmunks, groundhogs, raccoons, voles, shrews, skunks, field mice, moles, weasels, muskrats, mink, fishers, flying squirrels, red fox, and coyotes. Beneficial insects, including pollinators, are also represented at Mount Auburn. In addition to the insects naturally found on the grounds, Mount Auburn houses a honey bee apiary and has a certified beekeeper on staff.
Though also present, amphibians, reptiles, and fish are less abundant than birds or mammals. Intense manipulation of the grounds during the 19th century and heavy pesticide use for most of the 20th century likely impacted their populations over time. We no longer rely on toxic herbicides to maintain our grounds, and recent habitat restoration projects have crated the spaces these species need to survive. Following strict conservation guidelines, the Cemetery started to reintroduce three native amphibian species in 2015: American toads, spring peepers, and gray tree frogs. All three species have since reached successful breeding populations on our grounds, and the chorus of trills and peeping adds a previously lacking element to the springtime landscape. We hope to introduce additional species in the future. Some amphibians, reptiles, and fish under consideration for reintroduction include the blue-spotted salamander, brown snake, northern red-belly snake, musk turtle, golden shiner, and banded sunfish.
Planning and Planting for Wildlife
What is it that makes the Cemetery so welcoming for such a diverse range of wildlife species? Mount Auburn walks the line between ornamental landscape and natural, or even wild, terrain. Small-scale wildflower meadows, pocket butterfly gardens, and curbed/fenced burial lots managed as native perennials gardens dot the Cemetery’s landscape, providing food, cover, and breeding opportunities for insects and other native wildlife. Emergent plant zones border the banks of its four water bodies improving water quality and providing habitat for fish and other aquatic species. And in the historic center of Mount Auburn, fescue grasses requiring less frequent mowing now stand in the place of traditional turf to provide additional cover for various wildlife species. These naturalized areas offer diverse conditions that allow a range of wildlife to thrive and together create a network of spaces that facilitate safe movement through our landscape.
Mount Auburn’s landscape was heavily manipulated and intensely managed for a long time, but it has balanced the ornamental with the natural in recent years. The native woodland restoration at Consecration Dell, a project begun nearly 30 years ago, started Mount Auburn on its current path. Since then, the Cemetery has prioritized using native plant material that has habitat value in its landscaping projects. Likewise, Mount Auburn’s standards of beauty no longer involve keeping all 175 acres of its grounds “crisp and clean.” Instead, maintenance practices now consider the integrity and productivity of its diverse ecosystems. In specific designated areas, fallen branches remain in place to provide habitat for fungi and cover for invertebrates, amphibians, and small animals. In other areas the remnants of flowering perennials and ornamental grasses stand throughout the winter months to provide wildlife cover and wintertime interest. In the video below, Mount Auburn Gardening Supervisor Steph Almasi shares the wintertime interest and habitat benefits in Asa Gray Garden.
A Living Laboratory
A team of Mount Auburn staff, academic research collaborators, and volunteer citizen scientists now study the health of Mount Auburn’s landscape and its wildlife communities through a series of ongoing research projects. The data collected through this monitoring allows the Cemetery to evaluate its past efforts to improve biodiversity and informs our future goals.
From one scientific study, we now understand what dragonfly species are taking advantage of Mount Auburn’s habitat and successfully breeding at the Cemetery. Another study, which documents the presence and abundance of pollinators (insects and other species), allows us to evaluate the effectiveness of the plant material used in our pollinator gardens. And using a combination of bio-acoustic studies and mist nets to capture and release species, scientists have documented big brown bats, red bats, hoary bats, and little brown myotis in the Cemetery. Bat houses installed on the grounds in 2020 will further the bat research and monitoring already underway. An urban coyote study is now also underway.
Biodiversity in the Face of Climate Change
When arthropods like caterpillars and beetles emerge each spring to feed on budding leaves and flowers, they become a food source for the migratory birds seeking temporary shelter at the Cemetery. Temperature is the prime factor impacting the emergence of leaves and flowers, while day length is the primary factor influencing bird migration. However, with accelerated climate warming, Mount Auburn’s trees and shrubs are budding and leafing out earlier than ever. So how will an earlier horticultural spring, and consequently earlier arthropod activity, impact the food needs of spring migrants arriving at roughly the same time each year? Three studies now underway at Mount Auburn are attempting to answer this question.
The first effort is a phenology study that tracks the timing of life cycle stages, or phenophases, for ten deciduous tree and shrub species. Volunteers document weather conditions and collect the dates for budburst, leaf emergence, flower opening, and when leaves unfold at every specimen in the study. As part of a second study project, volunteers inspect the specimens on our phenology trail for evidence of arthropod activity each spring. Data collectors examine the underside of leaves for the number of arthropods present, diversity of species, and leaf damage. Every spring, a third survey documents all breeding species seen or heard at 16 points in the Cemetery. Nesting behavior, such as transporting nest materials or feeding newborns, is also recorded.
All three studies collect valuable data that helps us understand how weather and climate impact Mount Auburn’s wildlife communities and their habitats. With this information, Mount Auburn can develop an even more resilient landscape that continues to meet the needs of its wildlife inhabitants.
Mount Auburn’s Citizen Science Naturalist Program brings a community of well-trained volunteers together to support the biodiversity research underway at Mount Auburn. After completing an initial Naturalist Training program, volunteers can serve as capable research assistants and informal public educators.
The Citizen Science Naturalist Program is open to all ages, providing opportunities for adults, K-12 schools, and homeschool networks to connect with nature in a meaningful way. To sign up or learn more about current volunteer opportunities, contact Mount Auburn Director of Urban Ecology & Sustainability Paul Kwiatkowski at firstname.lastname@example.org.
As part of our Climate Action and Sustainability Plan, Mount Auburn has identified short- and long-term goals to strengthen the value of this important urban habitat.
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By Lawrence Millman
If flowers are commonly placed on a loved one’s final resting place, why shouldn’t lichens be allowed to reside on that loved one’s gravestone? After all, a lichen on a gravestone occupies a branch on the tree of life considerably closer to the branch occupied by that loved one than a chrysanthemum. Plus, that lichen could have an aesthetic quality similar to an attractive mosaic.(more…)