The Baltimore Ecosystem Study (BES) has established a network of
long-term permanent biogeochemical study plots. These plots will
provide long-term data on vegetation, soil and hydrologic processes in
the key ecosystem types within the urban ecosystem. The current
network of study plots includes eight forest plots, chosen to
represent the range of forest conditions in the area, and four grass
plots. These plots are complemented by a network of 200 less intensive
study plots located across the Baltimore metropolitan area.
Plots are currently instrumented with lysimeters (drainage and
tension) to sample soil solution chemistry, time domain reflectometry
probes to measure soil moisture, dataloggers to measure and record
soil temperature and trace gas flux chambers to measure the flux of
carbon dioxide, nitrous oxide and methane from soil to the atmosphere.
Measurements of in situ nitrogen mineralization, nitrification and
denitrification were made at approximately monthly intervals from Fall
1998 - Fall 2000. Detailed vegetation characterization (all layers)
was done in summer 1998.
Data from these plots has been published in Groffman et al. (2006,
2009) and Groffman and Pouyat (2009).
In November of 1998 four rural, forested plots were established at
Oregon Ridge Park in Baltimore County northeast of the Gwynns Falls
Watershed. Oregon Ridge Park contains Pond Branch, the forested
reference watershed for BES. Two of these four plots are located on
the top of a slope; the other two are located midway up the slope.
In June of 2010 measurements at the mid-slope sites on Pond Branch
were discontinued. Monuments and equipment remain at the two plots.
These plots were replaced with two lowland riparian plots; Oregon
upper riparian and Oregon lower riparian. Each riparian sites has four
5 cm by 1-2.5 meter depth slotted wells laid perpendicular to the
stream, four tension lysimeters at 10 cm depth, five time domain
reflectometry probes, and four trace gas flux chambers in the two
dominant microtopographic features of the riparian zones - high spots
(hummocks) and low spots (hollows).
Four urban, forested plots were established in November 1998, two at
Leakin Park and two adjacent to Hillsdale Park in west Baltimore City
in the Gwynns Falls. One of the plots in Hillsdale Park was abandoned
in 2004 due to continued vandalism.
In May 1999 two grass, lawn plots were established at McDonogh School
in Baltimore County west of the city in the Gwynns Falls. One of these
plots is an extremely low intensity management area (mowed once or
twice a year) and one is in a low intensity management area (frequent
mowing, no fertilizer or herbicide use). In 2009, the McDonogh plots
were abandoned due to management changes at the school.
Two grass lawn plots were established on the campus of the University
of Maryland, Baltimore County (UMBC) in fall 2000. One of these plots
is in a medium intensity management area (frequent mowing, moderate
applications of fertilizer and herbicides) and one is in a high
intensity management area (frequent mowing, high applications of
fertilizer and herbicides).
Literature Cited
Bowden R, Steudler P, Melillo J and Aber J. 1990. Annual nitrous oxide
fluxes from temperate forest soils in the northeastern United States.
J. Geophys. Res.-Atmos. 95, 13997 14005.
Driscoll CT, Fuller RD and Simone DM (1988) Longitudinal variations in
trace metal concentrations in a northern forested ecosystem. J.
Environ. Qual. 17: 101-107
Goldman, M. B., P. M. Groffman, R. V. Pouyat, M. J. McDonnell, and S.
T. A. Pickett. 1995. CH4 uptake and N availability in forest soils
along an urban to rural gradient. Soil Biology and Biochemistry
27:281-286.
Groffman PM, Holland E, Myrold DD, Robertson GP and Zou X (1999)
Denitrification. In: Robertson GP, Bledsoe CS, Coleman DC and Sollins
P (Eds) Standard Soil Methods for Long Term Ecological Research. (pp
272-290). Oxford University Press, New York
Groffman PM, Pouyat RV, Cadenasso ML, Zipperer WC, Szlavecz K,
Yesilonis IC,. Band LE and Brush GS. 2006. Land use context and
natural soil controls on plant community composition and soil nitrogen
and carbon dynamics in urban and rural forests. Forest Ecology and
Management 236:177-192.
Groffman, P.M., C.O. Williams, R.V. Pouyat, L.E. Band and I.C.
Yesilonis. 2009. Nitrate leaching and nitrous oxide flux in urban
forests and grasslands. Journal of Environmental Quality 38:1848-1860.
Groffman, P.M. and R.V. Pouyat. 2009. Methane uptake in urban forests
and lawns. Environmental Science and Technology 43:5229-5235. DOI:
10.1021/es803720h.
Holland EA, Boone R, Greenberg J, Groffman PM and Robertson GP (1999)
Measurement of Soil CO2, N2O and CH4 exchange. In: Robertson GP,
Bledsoe CS, Coleman DC and Sollins P (Eds) Standard Soil Methods for
Long Term Ecological Research. (pp 258-271). Oxford University Press,
New York
Robertson GP, Wedin D, Groffman PM, Blair JM, Holland EA, Nadelhoffer
KJ and. Harris D. 1999. Soil carbon and nitrogen availability:
Nitrogen mineralization, nitrification and carbon turnover. In:
Standard Soil Methods for Long Term Ecological Research (Robertson GP,
Bledsoe CS, Coleman DC and Sollins P (Eds) Standard Soil Methods for
Long Term Ecological Research. (pp 258-271). Oxford University Press,
New York
Savva, Y., K. Szlavecz, R. V. Pouyat, P. M. Groffman, and G. Heisler.
2010. Effects of land use and vegetation cover on soil temperature in
an urban ecosystem. Soil Science Society of America Journal
74:469-480."
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Herbicides as anthropogenic drivers of eco‐evo feedbacks in plant communities at the agro‐ecological interface
Herbicides act as human-mediated novel selective agents and community disruptors, yet their full effects on eco-evolutionary dynamics in natural communities has only begun to be appreciated. Here we synthesize how herbicide exposures can result in dramatic phenotypic and compositional shifts within communities at the agro-ecological interface and how these in turn affect species interactions and drive plant (and plant-associates’) evolution in ways that can feedback to continue to affect the ecology and ecosystem functions of these assemblages. We advocate a holistic approach to understanding these dynamics that includes plastic changes and plant community transformations and also extends beyond this single trophic level targeted by herbicides to the effects on non-target plant-associated organisms and their potential to evolve, thereby embracing the complexity of these real-world systems. We make explicit recommendations for future research to achieve this goal and specifically address impacts of ecology on evolution, evolution on ecology, and their feedbacks so that we can gain a more predictive view of the fates of herbicide-impacted communities.
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- NSF-PAR ID:
- 10164216
- Date Published:
- Journal Name:
- Molecular Ecology
- ISSN:
- 0962-1083
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Background and Aims When plant communities are exposed to herbicide ‘drift’, wherein particles containing the active ingredient travel off-target, interspecific variation in resistance or tolerance may scale up to affect community dynamics. In turn, these alterations could threaten the diversity and stability of agro-ecosystems. We investigated the effects of herbicide drift on the growth and reproduction of 25 wild plant species to make predictions about the consequences of drift exposure on plant-plant interactions and the broader ecological community. Methods We exposed potted plants from species that commonly occur in agricultural areas to a drift-level dose of the widely used herbicide dicamba or a control solution in the glasshouse. We evaluated species-level variation in resistance and tolerance for vegetative and floral traits. We assessed community-level impacts of drift by comparing species evenness and flowering networks of glasshouse synthetic communities comprised of drift-exposed and control plants. Key Results Species varied significantly in resistance and tolerance to dicamba drift: some were negatively impacted while others showed overcompensatory responses. Species also differed in the way they deployed flowers over time following drift exposure. While drift had negligeable effects on community evenness based on vegetative biomass, it caused salient differences in the structure of coflowering networks within communities. Drift reduced the degree and intensity of flowering overlap among species, altered the composition of groups of species that were more likely to coflower with each other than with others, and shifted species roles (e.g., from dominant to inferior floral producers and vice versa). Conclusions These results demonstrate that even low levels of herbicide exposure can significantly alter plant growth and reproduction, particularly flowering phenology. If field-grown plants respond similarly, then these changes would likely impact plant-plant competitive dynamics and potentially plant-pollinator interactions occurring within plant communities at the agro-ecological interface.more » « less
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1111/mec.15510
