A Poster Introducing BES III

BES at the All Scientists' Meeting

Every three years, the participants in the Long-Term Ecological Research (LTER) Network meet to share and compare results, and to plan for the future.  this effort, involving more than one thousand researchers, educators, artists, and other collaborators in LTER, is called an All Scientists' Meeting. The details of this large meeting can be found on the website of the LTER Network: http://www.lternet.edu/node/49531

Members of BES will be presenting posters, plenary talks, and workshops.  We'll report on some of the highlights after the meeting is done.

An Overview of BES for the ASM

Each LTER site is required to present a poster at the meeting.  The posters measure no larger than 4 x 4 feet, but in order to make them legible to readers viewing the posters some 3 to 4 feet distant, remarkably little text can be included.  It is a challenge to choose a breadth of research and education, and keep the poster legible and clear.  I hope that I have managed to do that with this year's poster.

The poster starts in the middle column, providing a point-by-point abstract of the nature of Phase III of BES.    It indicates that BES III builds on the integrative concepts that have motivated our research, education, and community engagement since 1997.  However, due to the increasing concern with issues of sustainability in the Baltimore region, and the capacity of this coastal metropolis to adapt to the effects of climate change, we chose to focus on that shifting policy environment as a way to move BES forward.  As mentioned in earlier posts, we adopt the idea that Baltimore metro is aiming to move from the existing sanitary to an envisioned sustainable city.  

The new guiding question for BES flows from the sustainability focus, and employs a resilience framework that relies on adaptive processes in both the social and the biophysical aspects of the interacting urban system.  Follow the arrows in the poster to build your understanding as you move through it.

The new guiding question and its subquestions then flow out into nine examples of conceptual or empirical work in BES III. 

Trees, Vegetation: Patchiness, Change, and Function

Four examples are groupse in the left hand panel.  These results  focus on the status and change of trees, tree canopy, and the vegetated components of the urban land cover complex.  The results are these:

1. Total forest cover has remained the same from 1914 to 2005, but the size of individual forest patches has decreased markedly.  Fragmentation is evident in this survey of the Gwynns Falls Watershed.  The work is published by Zhou et al. (2011).

2. Nowak and Greenfield (2012) showed that 17 of 20 US cities had less tree canopy over two times separated by about 5 years in the recent past.  Baltimore was among the decreasers.  Only Syracuse, NY had an increase in tree canopy.  This result is perhaps surprising given the policies and programs that many cities have put in place to increase their tree canopy coverage.

3. The heat island is one of urban ecology's most robust generalizations.  However, what kind of heterogeneity is there at fine to medium scales in the heat stress experienced within cities, and who suffers as a result?  Huang et al. (2011) show that in the Gwynns Falls Watershed, which encompasses patches that represent both old and new suburbs,  dense old residential areas, commercial, transportation corridors, agriculture, and parks, among others, that neighborhoods with less social-economic wherewithal were more susceptible to the hotspots in the heat island. 

4. There is controversy concerning the relationship of trees to crime.  A statistical analysis was conducted by Austin Troy and colleagues (2012).  They discovered that tree canopy was almost always associated with less crime in Baltimore City and Baltimore County.  They determined that other variables did not confound the general relationship.  However, the exceptional neighborhoods, where trees were in fact associated with higher crime, were those in which volunteer tree vegetation was present on abandoned industrial parcels adjacent to residential areas.

The Urban Stream Dis/Continuum: Patterns and Processes

1 - 2. The results clustered in the right hand panel of the poster focus on streams.  Kaushal and Belt (2012) have proposed a conceptual refinement to the stream continuum concept to apply this widely used comparative tool to urban systems.  They emphasize the role of engineering, and the effects of enhanced connections in hydrological flow paths, along with the effects of disruptions in hydrological flows.  Some of these connections and disconnections are intentional, while others are incidental to the way water is routed.  They present data to show that stream contamination depends on where in this complex dis/continuum a sampling station is located.

3. Detention basins are designed to control the flow of stormwater and reduce the loading of copious rains into storm sewers while continuing to avoid street and structure flooding.  Neil Bettez and Peter Groffman (submitted for publication) have shown that although several kinds of detention structures were engineered to control stormwater, in fact, they are also adaptive for reducing the amount of nitrate in stormwater.  They thus can contribute to improving the water quality downstream.  Some of these engineered structures facilitate enough biological processing of nitrate that they do better than natural riparian zones in the area.

Social and Educational Processes

The bottom center panel contains two examples.  Both deal with information sharing and exchange.

1. Bess Caplan and Alan Berkowitz present a learning progression, to help understand how students ability to use scientific thinking and explanation might develop.  What students bring to the classroom, and their experience with scale, unseen forces, and the use of models beyond simple narratives are all part of the progression.  This concept is helping teachers to improve students' ability to learn scientific concepts and to prepare better for scientific citizenship.

2. Michele Romolini, a doctoral student at the University of Vermont, presents one of her analyses of stewardship organizations in Baltimore.  Dividing the organizations into non-governmental and governmental ones, helps understand the marshaling and sharing of information.  In addition, understanding which organizations are clustered around key institutions that act as information sources, and which are relatively isolated from such nodes, helps ensure the most equitable distribution of environmentally crucial information.

The poster places these results and concepts into a graphical form.  This will be on display throughout the All Scientists Meeting in Colorado during the week of 9 - 13 September 2012.  We hope it gives a little flavor of where BES is going in its third phase, motivated by the pressure of cities to become more sustainable.

Publications

Huang, G., W. Zhou, & M.L. Cadenasso. 2011.  Is everyone hot in the city?: Spatial pattern of land surface temperatures, land cover, and neighborhood socioeconomic characteristics in Baltimore, City, MD.  Jour. Environ. Manage. 92:1753-1759.

Kaushal, S.S. & K.T. Belt. 2012. The urban watershed continuum: evolving spatial and temporal dimensions. Urban Ecosystems 15:409-435

Nowak, D.J. and E.J. Greenfield. 2012. Tree and impervious cover change in U.S. cities. Urban Forestry and Urban Greening. 11:21-30.

Troy, A. J.M. Grove & J. O’Neil-Dunne. 2012. The Relationship between Tree Canopy and Crime Rates across an Urban-Rural Gradient in the Greater Baltimore Region, Lands.  Urban Plann. 106: 262-270.

Zhou, W., G. Huang, S.T.A. Pickett, & M.L. Cadenasso.  2011.  90 years of forest cover change in the urbanizing Gwynns Falls watershed, Baltimore, Maryland: spatial and temporal dynamics.  Landscape Ecology 26:645-659

BES II Project Outcomes

What's This All About?

Second story bays, Charles Village neighborhood, Baltimore.  BES LTER Photo.

BES, as a Long-Term Ecological Research project, is funded in six year increments.  BES II actually lasted for seven years due to a change in the scheduling of the grant cycle by the National Science Foundation (NSF).  We are obliged to produce a formal report to NSF that summarizes what we have done and what its broader impacts are.  This report is technical, encyclopedic, and detailed, and we will make it available when it is finished.  However, NSF also requires us to prepare a "plain language" summary which is posted on the Research.Gov website.  For the interest of the BES community, I'm posting that "Project Outcomes" report here.

A Premier Urban Research and Education Platform

Over the last seven years, the Baltimore Ecosystem Study (BES), Long-Term Ecological Research project has consolidated as a comprehensive, multidisciplinary platform for urban socio-ecological research.  It has demonstrated that concepts fundamental to mainstream ecology, such as the ecosystem, the watershed, and the shifting patch mosaic, help to understand the linked, human-natural components of cities, suburbs, and exurbs.  The knowledge generated has helped educate citizens and students about nature and natural processes in cities.  BES results have helped managers and policy makers 1) to identify new opportunities for urban watershed management, 2) to enhance urban tree canopy and its benefits, and 3) to employ ecological processes and amenities in neighborhood revitalization.  An important product is a new classification of urban land covers that combines social, physical, and biological features.

Sarah Ann Street, west Baltimore.  BES LTER Photo.

Knowledge About Ecosystem Processes

BES has produced new knowledge about urban stream behavior, documenting their disconnection from floodplain and ground waters.  It has shown increasing salt pollution in streams the long-term, and shown the effectiveness of stormwater “best management practices” in old residential neighborhoods.  Findings of stream research focused watershed management beyond the near-stream zone, and subsequent research on urban tree canopy documented reduced exposure to UVB radiation and reduction of the urban heat island effect.  The urban heat island has been shown to be very patchy in its potential negative effects on people, and hotspots of urban heat are distributed inequitably throughout the metropolis.  Other pollutants beyond heat are also patchy, with nitrogen deposited from traffic exhaust being both higher in general magnitude than expected, and concentrated around travel corridors.  The capacity of the urban system to absorb carbon (C) dioxide has also been documented, and daily and weekly patterns confirm the relationship of C dynamics to the activity patterns work and travel.  The vegetation in Baltimore results in less release of C to the environment than would occur without trees and lawns.

Biodiversity and Spatial Dynamics

The biological organisms other than people also have important roles in the urban ecosystem.  The identity of some animals has been homogenized across different cities, as expected, but local specialization still exists.  Urban soils contain a rich community of native and introduced species that contribute to soil metabolism and to the absorption of carbon dioxide and nitrates, taking these polluting compounds out of circulation.  New communities of aquatic animals establish in the novel habitats of stormwater detention ponds, and provide nutrient cycling services and support foodchains.  Notable members of some aquatic habitats are the introduced mosquitoes that can transmit West Nile virus (WNV) from birds to people.  The composition of mosquito communities shifts from rural to urban waters and containers, increasing the risk of WNV in the city.  Birds have been shown in other cities to depend upon the wealth of neighborhoods, but in Baltimore bird diversity responds to the structure of the tree canopy in different neighborhoods. 

Socio-Ecological Processes

BES research has evaluated other important interactions between the social and the biological ecology of Baltimore.  BES social scientists have discovered how the distribution of environmental "goods," such as parks and street trees, has changed over time in Baltimore, and how access to these amenities has varied among different groups.  Results show that African Americans in Baltimore today enjoy a high degree of access to parks and playgrounds compared to African Americans in other U.S. cities.  Examination of the history of environmental zoning variances documented inequitable decision making in Baltimore's past.  However, our research also shows that Black Baltimoreans are the beneficiaries of an "inherited" landscape.  In fact, a long history of segregation, both formal and informal, limited African American access to parks and playgrounds until large numbers of white residents left the city in the 1950s and 1960s.  It was only then that the city's black population "spread out," gaining access to park facilities once considered off limits.  An unexpected legacy of segregation is the contemporary association of toxic release inventory sites with white, working class neighborhoods.  Although areas of greater tree cover have less crime, not all residents consider urban trees to be an amenity.  For decades, both black and white residents of East Baltimore have opposed municipal tree-planting efforts.  In contrast, neighborhood associations during the first half of the 20th century were adept at attracting amenities, such as new street trees, while keeping out unwanted land uses.  BES social scientists adopted the theory of market segmentation to document the role of lifestyle differentiation as a key to understanding the shift from an industrial to a knowledge and service based economy in Baltimore. 

Riparian sycamore along the Gwynns Falls.  Photo by Charlie Davis.

Broader Impacts

The findings of BES have contributed to education of underserved communities, ecological urban design and planning, and discovery and valuation of ecosystem processes within the urban matrix from city to exurb.  Most fundamentally, BES has documented the existence and mechanisms of ecosystem processes in complex urban environments.  The BES research platform is poised to help inform, evaluate, and educate about the sustainability initiatives now being implemented in the Baltimore metropolitan region.

Swamps and the City: Part II

A special guest post by Prof. Grace S. Brush, Johns Hopkins University.

My last post discussed how the role of people in shaping the swampy systems of the Everglades had been erased.  That erasure paralleled how biophysical processes had in the past been ignored in thinking about urban systems.  Because Baltimore is a coastal city, it occurred to me while I was writing that post, that there were insights about the role of swamps and wetlands in the history of our city that would be worth exploring.

Prof. Grace Brush

Who better to lead us on that exploration than Professor Grace S. Brush, one of America's leading paleoecologists -- a scientist who studies past environments and the ecological networks that existed within them, usually by using fossil pollen or larger preserved parts of plants or animals?  Here is her essay, reminding us of Baltimore's important swampy heritage, and the implications for the Chesapeake Bay that result from the reduction or obliteration of those many swampy features. S.T.A.P.

THE VERY WET PRE-COLONIAL LANDSCAPE OF THE CHESAPEAKE BAY, by Prof G.S. Brush

            A prevailing question today, as the historical fish harvests of the Chesapeake and other aquatic systems are greatly diminished, is “What was the land really like, when the water was clear and seafood abundant? 

             Pollen and seed records in dated sediment cores indicate a forested landscape 300 years ago with most herbaceous plants belonging to wetland species.  Pre-colonial soils exposed along river cuts contain water lily pollen. Sedge seeds were common in the sediment.  Rainfall runoff  was minimal in a pervious forest  floor rich in leaf litter and decomposing wood.  Hence groundwater was constantly recharged, creating wet soggy ground.  Seeds of submerged macrophytes in cores collected in present day tidal fresh water marshes record open water at those locations in pre-colonial time. 

Beaver landscape (Morgan 1867)

Historical maps published in 1897 show springs at the mouths of many tributaries.  Druid Hill Park in Baltimore City has structures built for drinking water for horses at sites where ground water surfaced.  They are now dry. Upland trees such as black locust and species of oak are replacing wetland species like green ash and box elder on floodplains of many streams.  This phenomenon, which we have described as a “hydrological drought” is being reported in various parts of Eastern and Midwestern USA.  All through the watershed, a very large beaver population created many marshes behind the numerous dams they built on inland streams  All of the evidence points to a wet environment characterized by many marshes, swamps and ponds.

Baltimore, 1792, with agricultural clearing.

             Within a very short time following colonization, much of the watershed was converted to agricultural land, accomplished by cutting down the trees and draining and filling in wetlands and marshes.  This conversion was facilitated by the near extinction of the beaver population by the fur trade in the 18^th century.  The soil that eroded from the less pervious agricultural land -- along with fertilizers -- was transported by streams to estuarine waters.  Excess nitrogen, a major constituent of fertilizers, is particularly harmful because of its many potential transformations in the soil and water, making it available for generations of plant growth.  It can be removed from the system only by denitrification, where nitrogenous compounds are converted to elemental nitrogen and returned to the atmosphere.  Denitrification occurs almost entirely in wet, anaerobic environments, such as marshes and swamps.  The pre-colonial landscape, which was ideally suited for denitrification, was destroyed as nitrogen loads and sources increased.

Baltimore 1801, showing extensive, wet lowlands.

            Along with overfishing, the transformation of the landscape from wet to dry contributed directly to the fishery decrease in the Chesapeake Bay, as nitrogen not recycled to the atmosphere became a major contributor to increased eutrophication, anoxia and habitat loss in the Bay ecosystem.

Grace S. Brush, PhD, Department of Geography and Environmental Engineering, Johns Hopkins University, Baltimore MD

The map of the beaver dams is from Morgan, L. H.  1867.  The American beaver and his works.  New York: Burt Franklin (reprinted 1970).