Climate Impacts on Coastal Biodiversity in the Boston Harbor

The Boston Harbor was once considered one of the most polluted water bodies in America due to nitrogen and phosphorous loading from the discharge of untreated wastewater and sewage, which lead to its nickname in the 1980s as the “harbor of shame”; however, after decades of restoration and management efforts, water quality has improved dramatically and the harbor is now a model of successful conservation as evidenced by documented recovery of important indicator species such as eelgrass (Bowen et al., 2019).

This story of recovery is now being eclipsed by rising threats from climate change, particularly sea level rise (SLR), erosion, extreme storm events, warming waters, and non-native invasive species. The Boston Harbor Islands National Recreation Area consists of a series of Islands and peninsulas that are unique in their geological history as the only coastal drumlin archipelago in the U.S.

The Northeast coast of the United States is experiencing some of the fastest rates of sea level rise (SLR) in the world.

Since 1900, sea levels in Boston Harbor and surrounding areas have risen by about a foot (2.81 ±0.17 mm/yr), 3-4 times the global average (USGCRP, 2018). While there is high certainty that sea levels in the region will continue to rise in the coming decades, there is uncertainty in the magnitude that the region will experience and specific impacts on valued resources.

Current predictions range from 2-4.5 additional feet by 2100 (USGCRP, 2018). Sea level rise and predicted increases in storm frequency and intensity elevates the risk of coastal erosion, flooding and saltwater intrusion into habitats and human infrastructure located in the coastal zone; consequently, coastal socio-ecological systems are highly vulnerable to climate impacts. 

A systematic literature review was conducted in web of science and google scholar using search strings to understand the relative rates of change and risk of SLR and flooding across the BOHA and how these changes effect risk to biodiversity at different sites. The end product was a database cataloguing all climate and species-specific information from relevant papers and helped to identify the magnitude and spread of information on SLR and storms in relation to our species of interest.

Sea level rise and predicted increases in storm frequency and intensity elevates the risk of coastal erosion, flooding and saltwater intrusion into habitats and human infrastructure located in the coastal zone; consequently, coastal socio-ecological systems are highly vulnerable to climate impacts.

The need to establish reliable methods for inventory and monitoring of marine nearshore habitats has emerged directly out of a fast-track effort to begin using Boston Harbor and the islands as study sites to understand how experimental manipulation of the coastline (e.g., the installation of in-water reefs) might reduce wave energy and erosion on the Harbor Islands and the mainland coast while also protecting marine and upland resources. The NPS is one of many partners on the steering committee for the proposed Stone Living Lab at the Boston Harbor Islands, which would create an in-situ research station within BOHA where scientists, park managers, planners, developers, and others can design and test new nature-based approaches to climate adaptation, coastal resilience and ecological restoration in a high energy coastal environment.  

The initial scoping work for the proposed artificial reef project has made it clear that while there is a standard protocol for permanent rocky substrate (Northeast Temperate Network Rocky Intertidal Protocol), an analogous standard protocol for mixed coarse (sandy, cobble) substrates does not currently exist. This is important because the majority of the large middle Harbor Islands are surrounded by mixed coarse intertidal substrates (Bell et al. 2002). Park managers and their research partners along with the local, state and federal regulatory agencies would greatly benefit from an inventory and protocol in these abundant habitats to assess baseline conditions and track the effects of projects during and after installation as well as from extreme storm and other events

Data sources were used to deduce total known biodiversity within BOHA over the past 160 years. Data sources and protocols include those associated with the NPS Inventory and Monitoring program (e.g., Rocky Intertidal and Coastal Breeding Bird monitoring protocols), citizen science data from an intertidal bioblitz (Matassa 2009); platforms including iNaturalist, eBird, Global Biodiversity Information Facility (GBIF), and National Audubon's Christmas Bird Counts; state and academic monitoring programs (MA Department of Marine Fisheries seasonal bottom trawl survey) that sample or track species occurrence and movements (e.g., existing telemetry networks), and prior studies from the region (Eddy 2016).

Data sources were synthesized to develop:

A database of historically and recently observed species and substrates and maps of the distribution of occurrence and overlap of priority species. Data was organized by BOHA island and site, taxonomic group, occurrence (presence/absence) or abundance, time periods of occurrence (years, season, months), and level of identification (species, family).

The most observed group in the BOHA is the invertebrates, followed by algae, birds, fish, and lastly mammals. Eleven species were common to all target islands: American oystercatcher, common tern, common eider, laughing gull, herring gull, great black-backed gull, ring-billed gull, brant, spotted sandpiper, double-crested cormorant, and common periwinkle. Peddocks is the largest and most biologically diverse in all of the BOHA. Out of the remaining target islands (Lovells, Long, Rainsford, Georges, and Gallops), Lovells is nearly as diverse, followed by Long Island, Rainsford Island, Georges Island, and lastly Gallops Island. Out of the 22 non-target islands, Calf, Thompson, Outer Brewster, and Little Brewster are among the most diverse. The remaining non-target islands had less than 50 observed species.

A list of emergent species was developed to help anticipate and track species that have not historically been present on the BOHA but may be moving into the region through climate-induced shifts or that are non-native invasive species that could opportunistically establish themselves after disturbance from anthropogenic actions or natural processes.

This list was compiled based on a literature search, watch lists developed by the NE CASC Regional Effort on Invasive Species and Climate Change (RISCC) working group, and regional bioinvasion expert at UMass Boston and Amherst (Brian Cheng), MIT (Judy Pederson), and UNH (Jenn Dijkstra). The end product displays a matrix of species currently present in the park, projected timelines to arrival (e.g., based on range shift models where available) and potential impact on native biodiversity (ranked as negative, positive, neutral, unknown).

Preliminary data were collected on three islands, Gallops, Georges and Lovells in 2018due to their location within the harbor as a barrier to storm and wave impacts further into the harbor and mainland. Buchbinder (2018) found marked differences in species richness and physical characteristics among sites. In addition, preliminary work identified areas where the presence of potentially sensitive biota (e.g., shellfish beds, eelgrass) could pose challenges for compliance, or limit desired options for the type or timing of coastal alteration that could be implemented in the future. In 2019, Lucy Lockwood (UMass Boston) continued preliminary data collection on Peddocks Island. Additional site scoping will be conducted in the summer of 2021 on all target islands to collect information on site characteristics, biodiversity, and habitat features.

In addition, we will scope sites for preliminary detections of high priority species and habitats derived from preliminary synthesis work and the results of a NE NPS climate refugia workshop (March 2020). Collectively, these six sites will provide a broad range of shoreline segments, site conditions and habitat types representing mixed coarse substrates that are likely to be targets for adaptation actions. Metabarcoding and eDNA techniques will be explored through the collection and processing of water and sediment samples in collaboration with Lisa Komoroske (UMass Amherst).

Title: A novel monitoring framework to assess intertidal biodiversity in mixed coarse substrate habitats across the Boston Harbor Islands

USGS Principal Investigator: Michelle Staudinger, Science Coordinator, DOI Northeast Climate Adaptation Science Center, University of Massachusetts Amherst

NPS Point of Contact: Marc Albert, Natural Resource Partnerships Manager, National Parks of Boston

NPS Regional NRPP Contact: Amanda Babson, Coastal Landscape Adaptation Coordinator, Northeast Region, National Park Service, URI Bay Campus

Partner Investigators:

1. Michelle Staudinger (USGS): USGS co-lead, will oversee and coordinate all planning and field activities
2. Marc Albert (NPS): NPS co-lead, will provide overall project guidance; facilitate access to park lands; dissemination of final products to park managers and partners
3. Lucy Lockwood, USGS student contractor, Ph.D. Candidate, University of Massachusetts Boston School for the Environment, 100 William T. Morrissey Blvd. Boston, MA: co-lead field technician for data collection and statistical analyses
4. Aly Putnam, USGS student contractor, Ph.D. Candidate, University of Massachusetts Amherst, Department of Organismic & Evolutionary Biology: co-lead field technician for data collection and statistical analyses
5. Justin Taylor, USGS student contractor, MS, University of Massachusetts Amherst, Department of Environmental Conservation & Sustainability Science: Spatial & GIS specialist and graphic designer
6. Sarah Endyke, USGS NCASC student contractor, BS University of Massachusetts Amherst