The Effects of Climate Change on Benthic Macroinvertebrate Communities:
Ecological Risks Associated with Future
Anthropogenic Impacts in Vermont’s Streams
Future Anthropogenic Effects on Benthic Macroinvertebrates
Tanner Williamson, Samuel Parker, Emily Matys,
Jacqueline Maisonpierre, & Pace Goodman
Proposal Submitted to:
Breck Bowden (RSENR)
&
Tom Berry (TNC)
Proposal Submitted on:
February 27, 2009
Project Consultants:
Pace S. Goodman
Jacqueline A. Maisonpierre
Emily D. Matys
Samuel P. Parker
Tanner J. Williamson
Problem Statement
Climate Change, among other anthropogenic pressures, has the potential to impact macroinvertebrate
communities, thus affecting the ecological structure of Vermont’s streams.
Goal / Purpose Statement
Using benthic macroinvertebrates as indicators of stream health, we will investigate the various impacts
of anthropogenic pressures on Vermont’s streams. The data we compile will serve to predict future
ecological conditions of Vermont’s streams.
Justification
The combustion of fossil fuels and other anthropogenic activities are having a profound effect on earth’s
climate (NECIA 2006). The extent and magnitude of these effects is largely influenced by geographic
region and the ecosystems in which the particular climate can support. In the Northeastern United States
the projected impacts of climate change are largely dependent on various climate model scenarios.
(Hayhoe et al. 2007). Under the optimistic low-emission scenarios the mean seasonal temperatures of the
northeast could increase by 5 to 7.5°F in winter and 3 to 7°F in summer. Under the less desirable highemission scenarios the mean seasonal temperatures could warm by 8 to 12°F in winter and by 6 to 14°F in
summer. Both scenarios mean dramatic changes to the historical natural cycles that characterize the
region (NECIA 2006).
Since climate acts as the principle driving force for all ecological functions, it is without question that
changes in climate will have a broad range of impacts on ecosystems in the northeast and worldwide.
Some ecosystems will have a relatively insignificant response to these changes in climate, while others
will be dramatically impacted. River and stream systems will be among the latter, with a variety of
deleterious effects (Durance and Ormerod 2009). For this project we will focus on the effects of climate
change and other anthropogenic stressors on the macroinvertebrate communities in Vermont. These issues
are very important to consider because benthic macroinvertebrates are an essential component of stream
ecosystems. As primary consumers, they link the energy derived by autotrophic flora in the form of leaf
litter and algae to higher trophic levels, such as fish (Merritt and Cummins 1996). As climate change
pressures disrupt or impair the fecundity of these organisms the entire community structure of a stream or
river will change. These changes to the community structure will have a wide-felt impact on sport fishing
in Vermont. This, will, in turn, greatly alter the entire tourists industry as money from fishing-related
activities decreases. However, the extent and magnitude of the effects felt by climate change could be
mitigated if better land use practices were put in place.
Literature Review
Given the breadth of variables that could potentially impact macroinvertebrate communities as the climate
in the Northeast and Vermont shifts, we decided to focus on several key variables that are likely to pose
the most risk. Outlined below are the stressors that will have the most pronounced effects on
macroinvertebrate populations with respect to anthropogenic impacts (e.g. climate change and
urbanization).
Dissolved Oxygen
Jacobsen et al. 2008: The northeast US is expected to become warmer, which is inversely related to DO
levels, especially at night (Ficke et al. 2007). This paper looks into the daily fluctuation of DO and its
effect on BMI’s. Although this paper does not look into effects of time beyond a daily scale, ignoring
Global Climate Change and the effects of urbanization, the underlying concepts of the article can be
applied to future predictions due to information from other literature.
Beyene 2009: This paper looks at the effect of DO on both diatoms and BMI’s. In streams with low DO,
there were rarely any BMI’s found, while diatoms were still present. The article actually claims that
diatoms are better indicators of stream health in Africa due to the excessively high vulnerability of BMI’s,
whereas diatoms decrease at a more subtle and testable rate.
High Flow Events
Holomuzki and Biggs 2000: This study simulated high flow events in streams to investigate the impacts
of flooding on macroinvertebrate species persistence and dominance in stream ecosystems. Leptophlebiid
mayfly, mudsnail and the stony-cased caddisflies were the three species under investigation. Holomuzki
and Briggs looked at how refuge-seeking behavior and life-history traits affected these three species in
their response to high flow disturbances. All taxa responded by moving to deeper, more stable layers
within the streambed. This study provides valuable background information about the behavioral response
and survivorship of macroinvertebrates in response to flooding.
Suren and Jowett 2006: This study examined the effects of floods and droughts on invertebrates in a New
Zealand river. Two and a half years worth of data were collected including invertebrate sampling and
water flow levels. Although the study was based on a New Zealand river, data can be applied to Vermont
streams as the taxa examined in the study exist here as well. The study revealed EPT richness to only be
affected by the highest flow event of the season. This data may be extrapolated to EPT taxa in Vermont
streams in response to higher frequency and intensity storms caused by climate change.
Drought Conditions and Low Flow Events
Griswold et al. 2008: This paper examines the effects of drought conditions upon macroinvertebrate
populations in small headwater streams in southwestern Georgia.
Monk et al. 2008: This paper examines how spatial and temporal variation in hydrologic flow effects
macroinvertebrate community structure at 83 locations in England and Wales.
Boulton 2003: This paper examines the contrasting colonization rates of different macroinvertebrate taxa
following drought events in Australia and England.
Sedimentation
Larsen et al. 2009: A macroinvertebrate biotic index (MBI) was created to test the effect of changes in
habitat such as increased sedimentation. Macroinvertebrate scores decreased with increasing percentages
of fine sediments.
Mebane 2001: The increase of fine sediment supply (over spatial and temporal extents) due to
anthropogenic activities effect macroinvertebrate communities. This paper identifies the processes
responsible for sedimentation and the point at which organisms are affected. Effects of sedimentation
were only seen at the patch-to-patch scale. Common taxa were ranked according to their tolerance to fine
sediment
Compounding Effects of Urbanization
Finkenbine et al. 2000: This paper outlines the ecological implications of urbanization. The primary
stressor responsible for stream impacts in an urbanizing watershed is paving. The addition of these
impervious surfaces to the watershed had a direct link the hydrology of the stream system. More frequent
flood events and less groundwater infiltration are among the problems associated with increased
impervious area. With increased flood events comes greater stream power, which leads to increased bank
erosion. The excess sand and silt released during erosion tends to accumulate in epifaunal substrate, such
as boulders and cobbles. This process leads to what is known as embeddedness, a serious risk to benthic
organisms that inhabit the cobble-bottomed streams.
Strayer et al. 2003: This article, like Finkenbine et al., calls upon land use changes as the key stressor to
stream and river systems. They take a more specific approach using modeling as a determining factor.
Sabater et al. 2007: By comparing two stream systems in different climates this paper explores the
reasons why trophic structure is variable depending on the climate.
Proposed Effort
In an effort to identify the ecological risk associated with anthropogenic and global climate change
stressors on the environment, we will follow the EPA’s Ecological Risk Assessment framework. As a
basic outline, this is an effective tool for guiding our direction of action. It is an interconnected network
stressing problem formulation, analysis of data and risk characterization. The problem at hand has been
established, however, adjustments are accepted as more data is acquired and the issues are better
understood. Presently, the characterization of exposures and ecological effects of climate change and
anthropogenic stresses are being analyzed. This will enable us to distinguish the risks involved with these
stresses on macroinvertebrate communities within Vermont waterways. Ultimately, the data collected and
our analysis of such information will be utilized in communicating with others about the issues at hand.
There is also the potential for this assessment to result in some degree of risk management.
Figure 1. Conceptual model exploring the sources (rectangles), stressors (hexagons), effects
(parallelogram), and endpoints (ovals) of human impacts on benthic macroinvertebrates.
As a good starting point for this project, we decided to create a concept model involving the main
interactions surrounding macroinvertebrates in Vermont streams. We looked at natural processes to gain
an understanding of the role BMI’s play in a northeastern environment and created a list of possible
stressors related to human impacts for insight into potential future scenarios. By starting with this
framework, we can explore various aspects associated with macroinvertebrates without overwhelming
initial research. We can work off of prior knowledge regarding northeastern stream ecosystems, Global
Climate Change and urbanization to narrow our search to a finite number of macroinvertebrate
interactions and assess information gaps where research into the current literature would be necessary. As
we created this model, we discussed the importance of macroinvertebrates as the foundation of an
ecosystem and cited several stressors (e.g. dissolved oxygen, increased flow due to storm events and
urbanization, sediment load resulting from increased stream flow, periods of drought and compounding
urban effects) as the major stressors requiring further research.
The core of our research will be based on literature surrounding our topic of benthic macroinvertebrate
response to climate changes in Vermont. We will gather information from peer reviewed journals and
compile a report based on the sum of our findings. Additional information, however, may be acquired by
seeking knowledge from experts in the field. Michael Flinn, an expert in the field of entomology, and
Mary Watzin, who specializes in aquatic ecology, will be valuable resources in addition to specific
literature.
Effort Assignment
At this point we have split the project into five relevant components of anthropogenic changes in the
environment, focusing on the potential effects they may have on BMI's. Pace is looking into decreased
dissolved oxygen, Sam is looking into urban effects, Emily is researching sediment load, Tanner is
gathering information on the effects of increased drought and Jacqueline is looking at the potential
interaction between increased intensity storm events and BMI's. Once we have a general idea about these
specific components, we will meet and amalgamate our information into a more unified prediction of the
risk associated with increased anthropogenic degradation of the environment on BMI's and the associated
problems. We will also be attempting to discern between sources of human induced change, e.g. increased
development or Global Climate Change, and any possible natural changes.
Literature Cited
Beyene A, Addis T, Kifle D, Legesse W, Kloos H, Triest L (2009) Comparative study of diatoms and macroinvertebrates as
indicators of severe water pollution: Case study of the Kebena and Akaki rivers in Addis Ababa, Ethiopia. Ecological Indicators
9:381 – 392
Boulton, Andrew (2003) Parallels and contrasts in the effects of drought on stream macroinvertebrate assemblages. Freshwater
Biology 48:1173-1185
Durance, I., Ormerod, S. J. (2009) Trends in water quality and discharge confound long-term warming effects on river
macroinvertebrates. Freshwater Biology 54: 388-405
Ficke, A. D., Myrick, C. A., Hansen, L. J. (2007) Potential impacts of global climate change on freshwater fisheries. Rev Fish
Biol Fisheries 17:581-613
Finkenbine, J. K., Atwater, J. W., Mavinic D. S. (2000) Stream Health After Urbanization. Journal of the American Water
Resources Association 35:1149-1160
Griswold, Marcus, et al. (2008) Impacts of climate stability on the structural and functional aspects of macroinvertebrate
communities after severe drought. Freshwater Biology 53:2465-2483
Hayhoe, K., C.P. Wake, T.G. Huntington, L. Luo, M.D. Schwartz, J. Sheffield, E.F. Wood, B. Anderson, J. Bradbury, A.
DeGaetano, T. Troy, and D. Wolfe (2007) Past and future changes in climate and hydrological indicators in the U.S. Northeast.
Climate Dynamics. 28:381-407
Holomuzki, J.R. and Biggs, B.J.T (2000). Taxon-Specific Responses to High-Flow Disturbance in Streams: Implications for
Population Persistance. Journal of the North American Benthological Society, Vol. 19, No. 4 670-679
Jacobsen D, Marin R (2008) Bolivian Altiplano streams with low richness of macroinvertebrates and large diel fluctuations in
temperature and dissolved oxygen. Aquatic Ecology 42:643 – 656.
Larsen, S., Vaughan I.P., and Ormerod, S. J. (2009) Scale-dependent effects of fine sediments on temperate headwater
invertebrates. Freshwater Biology 54:203-219.
Mebane, C. A. (2001) Testing bioassessment metrics: macroinvertebrate, sculpin, and salmonid responses to stream habitat,
sediment, and metals. Environmental Monitoring and Assessment 67: 293-322.
Merritt, R. W., Cummins, K. W. (1996) An Introduction to the Aquatic Insects of North America. Kendall/Hunt Publishing
Dubuque, Iowa
Monk, Wendy, et al. (2008) Macroinvertebrate community response to inter-annual and regional river flow dynamics. River
Research and Applications 24:988-1001
NECIA-Northeast Climate Impact Assessment (2006) Climate Change in the U.S. Northeast: A report of the Northeast Climate
Impacts Assessment. Union of Concerned Scientists. Cambridge, MA
Suren, A. M. and Jowett, I. G. (2006). Effects of floods versus low flows on invertebrates in a New Zealand gravel-bed river.
Freshwater Biology. 51:2207-2227
Sabater, S., Elosegi, A., Acuna, V., Basaguren, A., Munoz, I., Pozo, J. (2007) Effect of climate on the trophic structure of
temperate forested streams. A comparison of Mediterranean and Atlantic streams. Science of the Total Environment 390: 475-484
Strayer, D. L, Beighley, R. E., Thompson, L. C., Brooks, S., Nilsson, C., Pinay, G., Naiman, R. J. (2003) Effects of land cover on
stream ecosystems: roles of empirical models and scaling issues. Ecosystems 6: 407-423