Baltimore Ecosystem Study Activities, Findings, and Contributions for 2013

Urban Long-Term Ecological Research (LTER) sites have a special mission within the National Science Foundation’s portfolio, and among the two dozen LTER sites.  All LTERs are obliged to conduct research that seeks to understand the status and changes of five core ecosystem processes: 1) primary production, 2) the flow of inorganic matter, 3) the flow of organic matter, 4) study of important populations, and 5) natural disturbance.

Of course, urban systems have crucial human and social components, as well as the artifacts and effects of social processes.  Consequently, the two urban LTERs must additionally be concerned with long-term 6) changes in land use and land cover, along with their ecosystem effects, 7) monitor the effects of human-environmental interactions, using integrated approaches to linking human and natural systems in an urban ecosystem environment, and 8) integrate research with local K-12 educational systems. 

Although BES III is motivated by novel theoretical concerns, as enumerated below, we wish to indicate how BES is achieving what may be considered our charter requirements from NSF.  The report for any given 12 month period is restricted by NSF to activities and outcomes for that period only.  So this report is not a cumulative summary of BES contributions.

One important point is that the activities and findings do contribute to our BES III conceptual structure, but the report is not divided to show that.  Those insights will be made available elsewhere.  For the BES III conceptual structure, see
The 2013 Annual Report is divided as 1) Activities, 2) Findings, and 3) Contributions.  New publications are available in on the website, and can be found by sorting by date in the publications browser

Activities in Core Research Areas For Urban LTERs

Primary Production

Production was measured in aquatic microfilm communities.  Tree production is measured every five years in the 195 point random sample of plots used to parameterize the Urban Forest Effects (UFORE) Model.

Flow of Inorganic Matter

Innovative modeling tools were developed for parcel scale stormwater flows.  This includes developing workflows and adaptation of process models for fine resolution, built environment influences on water routing at the parcel and streetscape scale.

The nitrogen budgets for nine, main BES watersheds across the urban-rural gradient were updated to refine estimates of (Inputs Outputs)/Inputs for each year between 1999 and 2010.  These improvements in the budget will better expose the role of land use, and the influence of climate on N retention.

The stream stage sensing equipment was upgraded at Pond Branch, a small forested reference watershed, in anticipation of the need to improve accuracy in stage readings and continuous discharge in all BES small watersheds.

Flow of Organic Matter

Carbon storage densities for trees, and the total for urban forests were estimated based on new data for 28 cities, including Baltimore.

Population Studies

Mosquito populations were sampled across the growing season and by life stage in city neighborhoods of contrasting socio-economic status, and along the 9 sampling sites of the Gwynns Falls watershed.  Several mosquito species in Baltimore are important human disease vectors, and are sensitive to both aquatic and terrestrial environmental conditions that vary across urban-rural gradients and that are expected to differ based on social features of neighborhoods.

The application of metacommunity theory as an organizing principle for long-term data on terrestrial and community composition and distribution was expanded.  Research tested the hypothesis that urban landscape structure mediates both local and regional controls on species richness.  Assessments of 209 woody plant communities, representing remnant and disturbed sites, included residential, commercial, parks, and vacant parcels.  Plankton community data were collected along with physiochemical information, and a mesocosm experiment was initiated to determine the interaction between nutrient loading and algal management practices.  Sediment coring in urban stormwater ponds was used to reveal the temporal trends in species assembly. 

Monitoring of earthworm populations continued in both rural reference and city park sites.  These species are influential in soil structure and nutrient processing.
Long-term monitoring of breeding bird populations continued, and a second year of winter bird data was added.


BES metacommunity research seeks to go beyond the common lumping of all urban habitats as “disturbed” to refine the understanding of environmental perturbations, stresses, species dispersal and priority effects, and legacies of various kinds of human management, including community gardens and minimally managed vacant lots.

Human Land Cover Change and Ecosystem Effects

Urban-rural transitions are notoriously complex, and so are not well quantified.  A statistical methodology that uses commonly available spatial data in a novel way was developed and applied.

Human-Environment Interactions

The history and geography of zoning was documented in order to understand when and why zoning regulations were passed, and to identify the major drivers in the efforts to segregate land uses and people.
A new method for analyzing the effects of pharmaceutical and personal care products (PPCPs) in situwas developed.  The effects of PPCPs and illicit drugs on microbial biodiversity and function  along the urban rural gradient in metropolitan Baltimore were documented via field survey and controlled experiment.  The role of illicit drugs in streams is a large knowledge gap.

In order to understand key aspects of the social structure of environmental decision making in the region, analyses of data on the interactions of environmental stewardship organizations in Baltimore was completed.
The relationship of tree cover and identity of the managers of tree cover were determined for neighborhoods based on social and economic differences.  The role of human behavior and neighborhood characteristics on lawn fertilization were assessed.

Integration with K-12 Education

Organizational Connections.  To institutionalize BES educational curricula and support continued greening efforts on school campuses, BES education specialists participated in the Baltimore Public School Green School Network.  BES supported a Research Experience for Teachers fellow in 2012-2013, and with leveraged funding supported a Teacher-In-Residence from Oregon. 

BES Teachers’ Institute.  Participants in the BES 2012 Teachers’ Institute and 2012 RETs participated in a further five, one-day professional development sessions during the 2012-2013 school year.  The 2013 summer BES Teachers’ Institute engaged teachers new to BES in a 7-day workshop that included not only science but math, social science, and art teachers.  The participants in these programs become part of a lasting community supporting science education in urban schools in Baltimore, and connect that community with national resources and support persons.

Student Learning.  A leveraged project (NSF MSP) is allowing us to conduct significant, long-term and cross-site research about how students think and learn along key strands of an environmental literacy learning progression.  Extensive research took place during this past year as part of the work of the Carbon, Water, Biodiversity and Citizenship Strands of the Pathways project.  Students and teachers completed “tests” to describe their thinking about key ideas in these subject areas, and student interviews were carried out to complement the written tests. 

Ecology Teaching.  BES collected rich and deep data during the teaching of one of the instructional units for each teacher, videotaping 4-5 class sessions, interviewing teachers before, during after the unit and at the end of the school year, interviewing and surveying students, and collecting artifacts from students and teachers.  These data, along with information about student and teacher learning from the Pathways environmental science literacy assessment, are helping us describe the connections between professional development, teacher knowledge and practices, and student engagement and learning.

Findings in Core Research Areas For Urban LTERs

Primary Production

Primary production in aquatic microfilms is influenced by the presence of pharmaceuticals and personal care products in Baltimore streams.  Fourteen species of trees, of a total of 20 measured, declined in Baltimore over the period 2001-2005.  The cover of all tree species in Baltimore declined by 1.9% over that period.

Flow of Inorganic Matter

Modeling demonstrated that fine scale dynamics and processing for drainage at parcel and streetscape scales is a critical component of the water and nitrogen retention processes in the built environment.
N retention is significant in the city and suburban watersheds, although this is likely to decrease with climate change and further urbanization.  This is in contrast to the common expectation that retention of limiting nutrients in urban watersheds would be low.

Finalization of the 2012 water year stream data allowed the significance of long-term trends extending for at least 10 years to be assessed for the first time in BES.  Different major watersheds across metropolitan Baltimore exhibited contrasting annual mean flow dynamics, with Gwynns Falls being slightly lower than the long-term averages, while the subwatersheds of the Gunpowder Falls had flows ca. 20% greater than average.

Flow of Organic Matter

Carbon storage densities for trees, and total urban forests were estimated based on new data for 28 cities.  Urban whole tree carbon storage densities averaged 7.69 kg C m-2of tree cover and sequestration densities averaged 0.28 kg C m-2 of tree cover per year in Baltimore.  Baltimore carbon storage density averaged 8.76 kg C m-2 with net sequestration of 0.168 kg C-2 yr-2.

Population Studies

The survey of mosquito populations found seventeen (17) species to breed in Baltimore, with only six (6) being found regularly.  The four most abundant species included two vectors of West Nile Virus, Culex pipiens, and C. restuans, and two invasives, Aedes albopictus, and Ae. japonicus

Terrestrial and aquatic metacommunity analyses revealed high variation in species turnover across space (i.e., high beta diversity).  Patterns of spatial turnover suggested that human preference for species composition over species richness is the predominant driver of urban beta diversity. 

Diplocardia zicsii, an earthworm species new to science, was described from Baltimore.


The composition of phytoplankton communities in stormwater retention ponds has shifted in response to the disturbance represented by algal management, with an increase in generalist versus strict herbivorous species.  Unmanaged ponds exhibited more variable species assembly dynamics, whereas zooplankton in managed ponds were more influenced by immigration from the regional species pool.  Initial analyses of plant communities in vacant lots demonstrate that legacies of demolition and of remnant gardens influence the beta diversity.

Ongoing soils research has discovered that anthropogenic factors, such as management, appear to overcome natural foil forming processes by increasing pH and nutrient concentrations in the surface 0-5 cm of urban soil profiles.

Human Land Cover Change and Ecosystem Effects

Urban-rural transition zones can be divided into three subzones, depending on land cover, imperious area, multivariate assessments of distance and accessibility variables, and geographically weighted regression coefficients.  A suburban transition is distinct from rural land, and is especially associated with the presence of buried streams.

Human-Environment Interactions

Mosquito population dynamics showed clear interactions with human behavior and associated physical structures.  In June, 82% of containers in the lower socio-economic status neighborhood contained mosquito larvae, compared to only 38% of containers in the higher socio-economic status neighborhoods.  By late July, the frequency fell to 66% in the lower socio-economic status location, but rose to 38% in the higher socio-economic status neighborhood.  The results that larger, more permanent breeding habitats support larger populations of biting adults by mid-summer.  Many refuse containers, such as cups and tires that supported larvae in June were dry by late July.  However, gardens and yard care, which were more common in the higher socio-economic status neighborhood, were more likely to maintain larval habitat.  Of 16 stormwater management structures sampled in 2012, pupal density was positively related to intensity of urban development.

Common drugs found in BES streams have the potential to influence the function and structure of aquatic microbial communities.  Aquatic microbial communities in urban sampling stations were less sensitive to pharmaceuticals and personal care products than rural stations.  Triclosan concentrations in Baltimore streams have the potential to lead to resistant bacteria and can change bacterial species composition.
Social analysis of networks of environmental organizations revealed 607 organizations participating in stewardship activities in the city.  A follow up survey indicated that the stewardship network is mixed sector, but that non-profits dominated, accounting for nearly 80% of the groups.  Baltimore environmental organizations and citizens define stewardship in social rather than ecological terms, with religious, mostly Christian, values often used. 

Indicators of lawn maintenance, such as mulching, pruning, presence of lawn, and presence of large trees, were associated with lower rates of crime, an important refinement beyond previous results based on tree cover alone.  Residential litter correlated positively with crime.  Transportation availability and bike lanes were associated with increased property values, although causality remains to be determined.

Integrate with K-12 Education

BES education research has discovered that some middle school students, and a few more high school students have moderate levels of environmental science literacy, while most hold only rudimentary levels. Teachers tend to be a bit more sophisticated in their understanding but the majority still don’t demonstrate the highest level of understanding as measured by our assessments.  Student and teacher literacy can be improved with hands-on activities that foster active learning and critical building of knowledge upon the base that learners start with. 

Teachers received training in environmental and social science research and teaching techniques  and learned the results of BES education research into student thinking and learning.  The Teachers’ Institute centered around concepts of 1) learning progressions; 2) principle- and evidence-based reasoning; and 3) any place on Earth is an ecosystem.


Contributions within Principal Disciplines

The study of beta diversity is one of the first to examine the mechanisms of between-habitat compositional turnover, rather than just the roles of local and of regional diversity in understanding urban biodiversity.
The novel, parcel based hydrological flow models and the associated workflows are applicable to urban systems generally, and fills a methodological gap.

The new methodology for assessing the effects of pharmaceuticals and personal care products (PPCPs) in situ is a contribution to the broader understanding of this understudied suite of contaminants in urban streams.  The associated demonstration of the effects on aquatic primary producers alerts researchers to the potential for these widespread contaminants to be important in urbanized watersheds more broadly.

Data collected by the bird monitoring project are count data.  Work with colleagues from the MU Department of Statistics is developing new Bayesian mixed model procedures for estimating count data. 

Contributions to Training

The annual field safety and Baltimore orientation workshop trained BES graduate students, postdocs, undergraduates and Urban Resources Initiative college interns.

Materials on communicating science in various venues, media, and formats are made available to BES undergraduates, graduate students and postdocs (  Science writing, writing for the public, communicating with reporters, communication with policy makers, the use of video and photography, and professional presentation strategies are among the topics presented. 

BES research and educational curricula were integrated into Parks & People’s educational and youth career development programs, KidsGrow (elementary grades), Project Blue (middle grades), and BRANCHES (high school grades).  These programs serve the predominantly minority populations of Baltimore City in particular.  KidsGrow reached 220 students in 2013.

A Research Experiences for Teachers (RET) fellow participated in a 6 week intensive research program mentored by a BES scientist.  The fellow is a science teacher at Independence School Local 1 in Baltimore. 
The project continues to provide valuable experience for newer USGS staff in (1) techniques for measurement of streamflow in small watersheds, some of which are in remote areas, (2) comparing stream flow conditions in small watersheds of differing land use, including urban, agricultural, and forested, and (3) evaluating flow conditions along an urban-rural land use gradient at 4 main stem stream gages in the Gwynns Falls watershed.

Cooperation with the Maryland Department of Public Safety and Correctional Services in our biodiversity research adds an instructional and training outcome through a novel citizen science approach improves the statistical power of our research.

Contributions beyond Science and Engineering

N retention results are relevant to new Watershed Implementation Plans (WIP) put in place to achieve goals set by new Total Maximum Daily Load (TMDL) regulations.
The statistical assessment of hydrological extremes made possible by the extension of the BES long term stream flow record to 10 years allows them to be included in regional hydrologic analyses and to be useful to regional water policy and management.

The coupled groundwater-surface models linked to BES are the first truly 3-D hydrologic model of this region.  It can be employed to answer questions about water residence times and fluxes on a large regional scale.

BES data on the concentrations of Pharmaceuticals and Personal Care Products as well as illicit drugs and their residues in Baltimore streams has informed policy makers and water quality managers of the importance of a relatively neglected category of contaminants in streams.  In addition, knowledge that these chemicals can influence stream productivity and function may help guide policy decisions.

Collaborative work leveraged NSF LTER and Cyberinformatics funding to develop sustainable software for watershed ecohydrological management that facilitates interaction, through crowd-sourcing, with residents and communities.

The influence of suburban tree cover spatial pattern on ecohydrology and runoff production can be simulated, visualized and used as a management strategy that incorporates residential preferences.  This provides a useful urban design and restoration tool.

Refined methodologies for assessing urban tree carbon storage and sequestration at the state and national level are relevant to climate change policies and attendant management strategies in place in the Baltimore region.

Interactions with the Baltimore City Office of Sustainability have confirmed the relevance of several of our data streams and engagement activities with six of the seven major components of the official sustainability plan.  BES researchers are in frequent communication with the Office of Sustainability concerning specific action targets and monitoring strategies.

Engagement with communities, non-profits, and government agencies has produced several positive outcomes:
•          Greening of public school campuses.
•          Integration with the City Mayor’s Office to transform vacant City-owned properties into community managed green space; supported the Baltimore Community Green Space land trust.
•          Provided technical and scientific information to community gardeners and other greeners through the Community Greening Resource Network.
•          Support for the Urban Waters Federal Partnership by implementing several Growing Green projects; shared data on community managed green spaces with Baltimore Indicators Alliance who developed an interactive online map for community use.

BES continues to explore linkages between science and art both as a stimulus to creativity in the sciences and as a medium of communication with non scientists.  The 2013 BES Artist-In-Residence was Patterson Clark, who in addition to being a graphic artist, writes an environmental blog for the Washington Post.  He prepared a graphical interface, ultimately to be installed on the BES website, as an engaging portal to BES research and education for the general public.