The Reality of Urban Forests

 Earthwise Aware  (EwA)'s Habitat Fragmentation Project was launched in late 2020 by director Claire O'Neill and EwA consultant Mina Burton. The project was developed in response to widespread habitat degradation at the Middlesex Fells, a 2,575-acre urban green space north of Boston.

This project aims to document habitat conditions at the Fells over time and mitigate further damage, help restore degraded habitats, and continue to meet recreational needs while protecting the park. EwA's protocols are rigorous, data-driven, and collaborative. This novel approach encourages community engagement while generating scientifically valuable data and knowledge.

This report outlines the aims and methods of EwA's Habitat Fragmentation Project and showcases recent data and findings. It also highlights new initiatives implemented in 2023 and shares our upcoming plans for 2024.

The Fells Habitat Fragmentation Project is just one of many participatory science projects that EwA runs in the Greater Boston Area. Additional study sites include Fresh Pond in Cambridge, the Growing Center in Somerville, and Horn Pond in Woburn.

 Learn more about EwA's approach to participatory science here. 

Habitat fragmentation is the loss of suitable feeding and living habitats for wildlife. At the Middlesex Fells, habitat fragmentation is driven by a number of factors, including rogue trails (user-created, non-official trails) and subsequent intrusion areas*, invasive species spread, pollution, and wildlife disturbance due to recreational activity.

*Portions of widening, erosion, or potential offshoots along trails.

In recent years, green spaces in Greater Boston, including the Middlesex Fells Reservation, have witnessed a sharp uptick in the proliferation of trampled areas along and off trails, accompanied by an explosion of informal trails. The potential ramifications encompass:

1. Habitat Fragmentation: Intrusion areas and informal trails have the potential to fragment habitats, disrupting the natural connectivity of ecosystems. Such fragmentation may lead to the isolation of species populations, diminished biodiversity, and heightened susceptibility to invasive species.
2. Habitat Degradation: The heightened human presence in intrusion areas and informal trails poses a risk of habitat degradation through trampling, soil erosion, vegetation damage, and pollution. These activities can disrupt crucial ecosystem functions and diminish the overall health of natural habitats.
3. Negative Impacts on Wildlife: Intrusion areas and informal trails can disrupt wildlife by causing habitat loss, displacement, and increased exposure to human disturbances. Such disruptions may interfere with crucial activities like breeding, foraging, and migration, affecting population dynamics and species diversity.
4. Safety Risks: Informal trails and intrusion areas, often lacking proper maintenance and signage, pose safety hazards to visitors. These areas may feature uneven terrain, concealed hazards, or proximity to hazardous wildlife, heightening the risk of accidents or injuries.
5. Loss of Wilderness Experience: The proliferation of intrusion areas and informal trails detracts from the wilderness experience for visitors seeking solitude and immersion in natural environments. It can result in overcrowding, noise pollution, and diminished opportunities for contemplation and reflection.
6. Legal and Regulatory Issues: Unauthorized intrusion into protected areas or the creation of informal trails may contravene environmental regulations and land management policies. Such activities may lead to legal consequences for individuals or organizations responsible for the unauthorized actions.

Addressing these repercussions often necessitates a multifaceted approach, encompassing education and outreach to foster responsible behavior, enforcement of regulations, restoration of degraded habitats, and strategic planning to mitigate the impacts of human activities on natural areas.

The Fells serves as a haven for biodiversity in an urban setting. This includes 130 vernal pools (60 of which are certified), 21 natural communities, and 13 Rare Species Core areas ( learn more about BioMap Core areas here ). The Fells is also an Important Bird Area (IBA) as certified by the National Audubon Society. Habitat fragmentation threatens the health, balance, and ultimately the survival of these valuable ecosystems at the Fells. The map below highlights key areas of ecological significance at the Fells.

EwA's habitat fragmentation project began in 2020 with a small yet dedicated 3-person team of rogue trail surveyors. Since then, the project has expanded to include two additional surveys: EwA's "Trail Report" pulls together biopollution (dog waste), Fells usage (recreational activity) surveys, and various fragmentation factors, including liter, trail erosion, and other trail conditions, while EwA's new Invasive Species survey brings a new level of detail to invasive monitoring. Both surveys are hosted on Anecdata, an open-source community and citizen science platform.

The figure below provides a snapshot of our three habitat fragmentation surveys and the types of data collected for each study. We strive to capture a useful combination of quantitative and qualitative data.

Together, these three studies indicate just how extensive habitat fragmentation is at the Fells. Rogue trail and biopollution surveys provide clear evidence of conditions on the ground, while recreational usage surveys offer important supplemental information. Usage surveys are best interpreted as a secondary data source because they may inadvertently introduce certain biases. Some recreational activities may not take place at the time of day at which surveys are conducted and, therefore, may be underrepresented. In addition, the presence of surveyors on trails may discourage certain activities. On the other hand, biopollution and rogue trail surveys capture evidence of activities even after they have taken place.

In addition to conducting our own surveys, we also integrate data from sources including MassWildlife and The Nature Conservancy's BioMap, recreational trail apps such as Gaia and AllTrails, and vernal pool data provided by the Natural Heritage and Endangered Species Program (NHESP).

For an aggregated map of all these sources alongside our own data, check out the EwA Fells Habitat Fragmentation Map below (best viewed in a separate browser window). This valuable resource is regularly updated and is the best place to thoroughly explore our habitat fragmentation data.  For tips on using this web app, check out our tutorial here .

In 2012, the Department of Conservation and Recreation (DCR) reported 79 miles of official roads and trails and 22.7 miles of rogue trails – per the  DCR Resource Management Plan  (p 35).

As of June 2023, EwA's rogue trail mapping team has completed a first pass of an area equal to 651.1 acres, representing 27% of the Fells' acreage. An additional 104.8 acres are currently being surveyed.

Patches were not selected based on the number of rogue trails present and would not be considered rogue trail heavy. Rather, we believe the completed patches to be average in terms of the number of rogue trails they contain. Recent scouting has identified survey patches with notably higher rogue trail usage. Therefore, our current dataset may represent a slightly low estimate of rogue trail presence.

As of June 2023, EwA's team of surveyors has recorded 300 rogue trails totaling 18.8 linear miles. An additional 602 rogue trailheads were reported, indicating that a minimum of 302 trails remain (602 rogue trailheads - 300 trails mapped = 302 trails yet to be surveyed in those areas).

Considering that these trails represent a low bound for the area being surveyed, and taking into account the 302 trails yet to be surveyed, a conservative rogue miles estimate [30%-50%] in the surveyed area is 24.44 - 28.20 miles. By extrapolating the current conservative estimate of rogue miles to the entire surface area of the Fells, we estimate a total of 90.52 - 104.44 miles of rogue trails at the Fells.

In addition to rogue trailheads and rogue trails, surveyors also record intrusion areas along trails. We define intrusion areas as portions of trail widening and other habitat disruptions, such as trampled areas. To date, surveys have recorded a total of 644 intrusion areas.

The map below shows all recorded rogue trails, rogue trailheads, and intrusion areas to date.

In 2023, the Fells witnessed a dominant presence of hikers and walkers, constituting 93.7% of its visitors. The remaining 6.3% of visitors were cyclists. Notably, just under half of these hikers and walkers were accompanied by dogs, totaling 47.3%. These figures closely mirror those of the previous year. See additional survey stats below.

More than half (52.7%) of reported groups did not have dogs. Of the groups with dogs present, most (70.2%) had only one dog present, with another 19.5% having two dogs. Groups with three or more dogs were considerably less common. The majority of dogs encountered were off leash (54.8%).

For a deeper dive into our Fells usage data, check out the  2023 Fells Usage Stats Highlights .

The map below showcases all biopollution records to date.

• Click the time slider widget at the top left to view the data in a time-enabled way. 
• Use the menu at the top right to view the map legend and toggle layers on and off.
• Use the "home" button on the left to return to the map's original extent.

This year, to better understand human presence's impact on wildlife, we calculated the corridor of influence (COI) for rogue and official trails at the Fells. A corridor of influence refers to the distance from human activity (in this case, distance from trails) at which wildlife is impacted.

In the presence of human activity, wildlife frequently stops to evaluate danger, diverting precious energy that would otherwise be spent foraging for winter or courting in mating season. Such disturbance also increases the risk of predation. The distance at which wildlife recognize and respond to human presence can range significantly. Recent  estimates from the U.S. Fish and Wildlife Service  proposed a 60-foot corridor of influence for amphibians, 150 feet for birds, and 400 feet for larger mammals.

Based on these guidelines, we calculated the corridor of influence using 60, 150, and 400-foot buffers for all recorded rogue trails and DCR trails at the Fells.

In the upcoming year, EwA will use corridors of influence as a guide to determine locations for rogue trail surveys. By focusing on areas that should be relatively "untouched," we can gauge the true extent of the spread of rogue trails at the Fells.

In March 2023, we introduced the  EwA Invasive Flora Patrol  on Anecdata. The protocol for this survey is detailed and thorough, yet fast and user-friendly enough to remain accessible for our participatory scientists. It includes novel features, including measures of spread and density, as well as plant phenology (flowering, fruiting, etc.).

In late 2023, EwA migrated our Fells Usage survey, which was initially a collaboration between EwA and the Friends of the Middlesex Fells Reservation (FOF), focusing on recording park activity, along with the EwA Biopollution survey, to the same platform. Anecdata's customizable format enabled us to consolidate the two studies into a comprehensive single survey named EwA Trail Report, enhancing surveyors' accessibility and user-friendliness. Furthermore, we expanded the survey's scope by integrating litter recording and documenting trail-related issues.

In addition to habitat fragmentation surveys, EwA now offers a plant phenology  "Pheno-lite" survey , a  rodenticide monitoring survey , and  EwA Buggy , an arthropod-plant interaction study, all through Anecdata.

We are excited to partner with an open-source platform built specifically for community-driven citizen science research. Anecdata features include a community forum, the ability to compare data across multiple survey sites, survey visit logs, and intuitive out-of-the-box data visualizations.

In 2024, we plan to develop visualizations to showcase the new invasive species data we've been collecting through Anecdata. These visualizations will incorporate factors including plant density, spread, and phenology.

Using our newly calculated corridors of influence, we plan to research a cumulative metric in which areas within the proximity of multiple trails will be weighted higher than those only impacted by one of two trails. This will allow us to determine which portions of the Fells are most highly fragmented by both formal and rogue trails.

Additionally, we hope to estimate the cumulative impact of multiple forms of habitat fragmentation (including rogue trails, biopollution, and invasive species) across various parts of the Fells.

Moving forward, we plan to use existing data to prioritize specific survey locations in the Fells. First, we intend to ground-truth areas considered "untouched" by corridors of influence to determine whether those locations are, in fact, undisturbed by human activity. We also plan to prioritize surveys in particularly rare or specialized natural communities and areas with high concentrations of vernal pools.

The work we do at EwA is made possible by the sustained dedication of our team leaders and participatory scientists.

Since its inception in April 2023, EwA's Invasive Flora Patrol has had 54 surveyors contribute data for a total of 736 records. After migrating our Trail Report to Anecdata in mid-November 2023, we saw 44 surveyors submit a total of 508 records in less than two months. In the last three years, Fells-focused participatory scientists have contributed more than 11,500 biopollution and park usage records to the Trail Report.

Our rogue trail surveying team has always been small but mighty. Currently, the team comprises three members, two of whom have been involved since the project's inception in late 2020. Thanks to their steadfast commitment, we have mapped trails in over a quarter of the Fells' 2,575 acres.

At EwA, we believe that truly effective and sustainable solutions arise from community and multi-stakeholder collaboration. We are deeply grateful to our partners who support and extend the work we do here at EwA. The success of this project would not be possible without the ongoing support of the Massachusetts Department of Conservation and Recreation (DCR) and the Friends of the Middlesex Fells Reservation.

We are also excited to report that our apps are being adopted by other local organizations. Friends of the Blue Hills and Friends of Horn Pond have used our apps to monitor biopollution and litter at their respective parks. Our invasive species protocol is being picked up in Somerville thanks to plant pathologist and EwA program leader Jennifer Clifford. EwA's new rodenticide monitoring app, the EwA SGARs Brigade, has already garnered support from close collaborator Jim Joyce at Friends of Horn Pond as well as local wildlife organizations, including Saving Arlington Wildlife, Saving Lexington Wildlife, and Saving Somerville Wildlife.

We look forward to continuing to work closely with these organizations in the upcoming year.