Assessing Cumulative Impacts of Shoreline Development

Project Details by Fiscal Year
2011 Fiscal Year Funding Amount
$300,000
Fund Source
Environment & Natural Resources Trust Fund
Recipient
U of MN
Recipient Type
Public College/University
Status
Completed
Start Date
July 2010
End Date
June 2012
Counties Affected
Aitkin
Becker
Cass
Crow Wing
Douglas
Hubbard
Morrison
Otter Tail
Todd
Legal Citation / Subdivision
M.L. 2010, Chp. 362, Sec. 2, Subd. 05h
Appropriation Language

$300,000 is from the trust fund to the Board of Regents of the University of Minnesota to evaluate near-shore, in-water habitat impacts from shoreline development activities to assist in the design and implementation of management practices protecting critical shorelands and aquatic habitat. This appropriation is available until June 30, 2013, by which time the project must be completed and final products delivered.

2011 Fiscal Year Funding Amount
$300,000
Proposed Measurable Outcome(s)

Click on "Work Plan" under "Project Details".

Measurable Outcome(s)

Click on "Work Plan" under "Project Details".

Project Overview

PROJECT OVERVIEW
Near-shore areas of lakes are critical to the health of lake ecosystems because they contain a majority of the vegetation and are generally the spawning areas for fish. Increases in the rate and extent of shoreline development - including docks, boatlifts, and other structures - and disturbance from recreational activity may be having cumulative detrimental impacts on these ecosystems. However, there is a lack of scientific knowledge about these impacts and that has been hindering lake managers in their ability to guide landowners toward better practices. Researchers from the University of Minnesota and the U.S. Geological Survey are using this appropriation to study the cumulative impacts of shoreline development on aquatic habitat, water quality, and fish populations in order to develop a tool that can be used to help guide sustainable near-shore development. Approximately 100 lakes in Aitkin, Becker, Cass, Crow Wing, Douglas, Hubbard, Morrison, Otter Tail and Todd counties will be used in the study.

OVERALL PROJECT OUTCOME AND RESULTS
The littoral zone contains all of the vegetation within a lake and is critical to the physical and biological integrity of lakes. Aquatic macrophytes and coarse woody structure provide refuge, foraging area, and spawning substrate for many fish species. The goal of this study was to evaluate shoreline development by measuring a number of variables that reflect human activity, including terrestrial vegetation, physical alterations, and in-lake structures. Previous studies have found reductions in abundance of aquatic vegetation and coarse woody structure; however, few studies have quantified the specific influence of docks on aquatic habitat structure. Coarse woody structure and three measures of macrophyte abundance increased with distance to the nearest dock structure. Presence of coarse woody structure and emergent species were significantly and negatively related to lake-wide dock density. We intensively investigated effects of lakeshore development on nearshore habitat across 11 northern Minnesota lakes using the Minnesota Department of Natural Resources Score Your Shore (SYS) survey to assess development intensity. Developed sites (a residence and dock present) had lower macrophyte species richness, emergent, and floating-leaf macrophytes and coarse woody structure than undeveloped sites (no residence, no dock). SYS score was a significant factor in models of most macrophyte community variables, supporting the hypothesis that site-scale development intensity is related to littoral vegetation. A fish Index of Biological Integrity decreased as the density of docks increased for the 11 intensively studied lakes. Development density across 29 lakes and 114 lakes were also examined, but less intensively. Effects of development in these less intensively studied lakes were less apparent for most lake macrophyte and fish community variables than for the intensively studied lakes. These findings suggest that riparian management on residential lots and reduced removal of aquatic macrophytes and coarse woody structure could improve fish habitat at both local and lake-wide scales of development.

PROJECT RESULTS USE AND DISSEMINATION
The project was conducted in conjunction with the Minnesota Department of Natural Resources and several meetings to disseminate our findings took place with Jacquelyn Bacigalupi, the Lake IBI Coordinator with MNDNR and colleagues. Additionally multiple conference presentations were given and two Master's theses resulted from the work on this project.

Project Details
Project Manager
First Name
Bruce
Last Name
Vondracek
Organization Name
U of MN
Street Address
1980 Folwell Ave
City
St. Paul
State
MN
Zip Code
55108
Phone
(612) 624-8748
Email
bvondrac@umn.edu