Skip to main content
U.S. flag

An official website of the United States government

Agricultural and Urban Management Practices have Hidden Costs and Benefits to Stream Health

Active
By Chesapeake Bay Activities June 4, 2024

The findings of the study highlight that management practices can have both hidden costs and benefits to fish and macroinvertebrates depending on regional and local factors like how many and what type of management practices are implemented.

Issue

Society spends billions of dollars each year on management practices like cover crops and green roofs to reduce nutrient and sediment pollution from entering rivers and streams that flow into the Chesapeake Bay. With growing interest in restoring stream biological health in the Chesapeake Bay watershed, we asked the question: “If management practices reduce pollutants, can they also benefit instream biological communities like fish and macroinvertebrates?”.

 

USGS Study

The USGS, in partnership with the Maryland Department of Natural Resources’ Biological Stream Survey (MBSS), examined the effects of agricultural and urban management practices on instream biological health in the Maryland portion of the Chesapeake Bay watershed. The MBSS program collects data on instream fish and macroinvertebrate (i.e., small organisms like mayfly larvae, worms, snails, and crayfish that are important to aquatic food webs) communities across three major regions that have different climate, elevation, and stream types: Coastal Plain, Eastern Piedmont, and Highlands. The researchers paired these fish and macroinvertebrate data with management practice data to find if management practices upstream of fish and macroinvertebrate samples had any unexpected costs or benefits on biological communities downstream. Because the majority of management practices  are targeted at reducing nutrients and sediment and are not generally intended to directly benefit fish or macroinvertebrates, the researchers expected to find either indirect effects of management practices on instream biological health through other variables like water quality or instream habitat, or small direct effects in areas with existing poor health, hypothesizing that management practices could provide some benefits to fish and macroinvertebrates. 

Conceptual diagram of how management practices could have downstream effects on freshwater ecosystems
Sources/Usage: Public Domain. View Media Details
Figure 1. Conceptual diagram of how management practices could have downstream effects on freshwater ecosystems. Management practices are implemented in agricultural and urban environments to reduce nitrogen (N), phosphorus (P), and sediment pollution from agricultural and urban land use. In this study, researchers tested for management practice co-benefits to instream biological condition, water quality, and instream habitat, where management practices may mitigate the effects of agricultural and urban land use on these variables.

Major Findings

Management practices had both positive and negative effects on stream health and specific groups of fish and macroinvertebrate communities that are good indicators of key stressors like water quality or sedimentation. Whether the effects were positive or negative depended on the region and overall stream health of the watershed. Key findings include:

  • Management practices benefitted macroinvertebrate and fish groups that need clean, rocky substrates and are sensitive to sedimentation like macroinvertebrates that scrape algae off rocks for food, and fish that lay eggs and make nests in “rocky reefs”.
  • Management practices had negative effects on mayfly macroinvertebrates (Ephemeroptera) that are sensitive to changes in water quality in some regions.
  • Watersheds with management practices also showed increased specific conductivity levels, a key water quality metric that indicates the amount of dissolved material in water, which can negatively impact fish and macroinvertebrates.
  • Management practices tended to have more positive effects in watersheds with poorer stream health, and more negative effects in watersheds with good stream health.
  • Identifying effects of management practices on fish and macroinvertebrates is challenging among the other complex stressors that impact fish and macroinvertebrates like land use, climate, instream habitat, and water quality.
6 panels indicate which Index of Biotic Integrity (IBI) region study units were matched within
Sources/Usage: Public Domain. View Media Details
Figure 2. Estimated effects of management practices (x-axis) for macroinvertebrate (top row, A,B,C), and fish (bottom row, D,E,F) response variables. Panels indicate which Index of Biotic Integrity (IBI) region study units were matched within. Colors on map of the state of Maryland indicate which IBI category study units were matched within. Positive values indicate that variable was higher in catchments with management practices, negative values indicate that variable was lower in catchments with management practices.

Management Applications

The findings of the study highlight that management practices can have both hidden costs and benefits to fish and macroinvertebrates depending on regional and local factors like how many and what type of management practices are implemented. Some examples of potential applications include:

  • Management practice implementation that is carefully planned at the watershed-scale that targets key stressors in areas with poor stream health could co-benefit fish and macroinvertebrate communities.
  • Management practices in areas with good stream health could be assessed for their potential negative impacts to fish and macroinvertebrates.
  • Management practices that increase specific conductivity like detention ponds could be assessed for potential ways to reduce their negative impacts.
  • More studies on the impacts of specific management practice types on fish and macroinvertebrates are needed to gain a better understanding of the hidden costs and benefits.

 

For More Information or to Request a Briefing

  • Sean Emmons (semmons@usgs.gov) is the primary contact for this project. Kelly Maloney (kmaloney@usgs.gov) is a secondary contact for this project.
  • The full study has been published in the Journal of Environmental Management (with open access) at https://doi.org/10.1016/j.jenvman.2024.121234.
  • The project team included Sean Emmons, Taylor Woods, Matthew Cashman, Olivia Devereux, Greg Noe, John Young, Scott Stranko, Jay Kilian, Katherine Hanna, and Kelly Maloney.

The findings of the study highlight that management practices can have both hidden costs and benefits to fish and macroinvertebrates depending on regional and local factors like how many and what type of management practices are implemented.

Issue

Society spends billions of dollars each year on management practices like cover crops and green roofs to reduce nutrient and sediment pollution from entering rivers and streams that flow into the Chesapeake Bay. With growing interest in restoring stream biological health in the Chesapeake Bay watershed, we asked the question: “If management practices reduce pollutants, can they also benefit instream biological communities like fish and macroinvertebrates?”.

 

USGS Study

The USGS, in partnership with the Maryland Department of Natural Resources’ Biological Stream Survey (MBSS), examined the effects of agricultural and urban management practices on instream biological health in the Maryland portion of the Chesapeake Bay watershed. The MBSS program collects data on instream fish and macroinvertebrate (i.e., small organisms like mayfly larvae, worms, snails, and crayfish that are important to aquatic food webs) communities across three major regions that have different climate, elevation, and stream types: Coastal Plain, Eastern Piedmont, and Highlands. The researchers paired these fish and macroinvertebrate data with management practice data to find if management practices upstream of fish and macroinvertebrate samples had any unexpected costs or benefits on biological communities downstream. Because the majority of management practices  are targeted at reducing nutrients and sediment and are not generally intended to directly benefit fish or macroinvertebrates, the researchers expected to find either indirect effects of management practices on instream biological health through other variables like water quality or instream habitat, or small direct effects in areas with existing poor health, hypothesizing that management practices could provide some benefits to fish and macroinvertebrates. 

Conceptual diagram of how management practices could have downstream effects on freshwater ecosystems
Sources/Usage: Public Domain. View Media Details
Figure 1. Conceptual diagram of how management practices could have downstream effects on freshwater ecosystems. Management practices are implemented in agricultural and urban environments to reduce nitrogen (N), phosphorus (P), and sediment pollution from agricultural and urban land use. In this study, researchers tested for management practice co-benefits to instream biological condition, water quality, and instream habitat, where management practices may mitigate the effects of agricultural and urban land use on these variables.

Major Findings

Management practices had both positive and negative effects on stream health and specific groups of fish and macroinvertebrate communities that are good indicators of key stressors like water quality or sedimentation. Whether the effects were positive or negative depended on the region and overall stream health of the watershed. Key findings include:

  • Management practices benefitted macroinvertebrate and fish groups that need clean, rocky substrates and are sensitive to sedimentation like macroinvertebrates that scrape algae off rocks for food, and fish that lay eggs and make nests in “rocky reefs”.
  • Management practices had negative effects on mayfly macroinvertebrates (Ephemeroptera) that are sensitive to changes in water quality in some regions.
  • Watersheds with management practices also showed increased specific conductivity levels, a key water quality metric that indicates the amount of dissolved material in water, which can negatively impact fish and macroinvertebrates.
  • Management practices tended to have more positive effects in watersheds with poorer stream health, and more negative effects in watersheds with good stream health.
  • Identifying effects of management practices on fish and macroinvertebrates is challenging among the other complex stressors that impact fish and macroinvertebrates like land use, climate, instream habitat, and water quality.
6 panels indicate which Index of Biotic Integrity (IBI) region study units were matched within
Sources/Usage: Public Domain. View Media Details
Figure 2. Estimated effects of management practices (x-axis) for macroinvertebrate (top row, A,B,C), and fish (bottom row, D,E,F) response variables. Panels indicate which Index of Biotic Integrity (IBI) region study units were matched within. Colors on map of the state of Maryland indicate which IBI category study units were matched within. Positive values indicate that variable was higher in catchments with management practices, negative values indicate that variable was lower in catchments with management practices.

Management Applications

The findings of the study highlight that management practices can have both hidden costs and benefits to fish and macroinvertebrates depending on regional and local factors like how many and what type of management practices are implemented. Some examples of potential applications include:

  • Management practice implementation that is carefully planned at the watershed-scale that targets key stressors in areas with poor stream health could co-benefit fish and macroinvertebrate communities.
  • Management practices in areas with good stream health could be assessed for their potential negative impacts to fish and macroinvertebrates.
  • Management practices that increase specific conductivity like detention ponds could be assessed for potential ways to reduce their negative impacts.
  • More studies on the impacts of specific management practice types on fish and macroinvertebrates are needed to gain a better understanding of the hidden costs and benefits.

 

For More Information or to Request a Briefing

  • Sean Emmons (semmons@usgs.gov) is the primary contact for this project. Kelly Maloney (kmaloney@usgs.gov) is a secondary contact for this project.
  • The full study has been published in the Journal of Environmental Management (with open access) at https://doi.org/10.1016/j.jenvman.2024.121234.
  • The project team included Sean Emmons, Taylor Woods, Matthew Cashman, Olivia Devereux, Greg Noe, John Young, Scott Stranko, Jay Kilian, Katherine Hanna, and Kelly Maloney.