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Illinois Department of Agriculture
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  Critical Trends Assessment Program   


Ecosystems in Illinois are deteriorating, their natural functions disrupted by fragmentation and stress. So concluded The Changing Illinois Environment: Critical Trends, a state-of-the-environment report published in 1994 by the Illinois Department of Energy and Natural Resources (now the Department of Natural Resources). This first “Critical Trends” report recommended that the state begin collecting statewide data on both the extent and condition of its ecosystems in order to determine the most effective and economical natural resources policy. The report quoted Abraham Lincoln: “If we could first know where we are and whither we are tending, we could better judge what we do and how to do it...”

To learn “where we are and whither we are tending,” the Critical Trends Assessment Program (CTAP) at the Illinois Department of Natural Resources developed the data collection tools and programs needed to monitor trends in Illinois ecosystems. Over the past several years, the CTAP team has completed an atlas of Illinois land cover, an inventory of resource rich areas, 30 regional watershed assessments, and several years of ecosystem monitoring. The team consists of staff from IDNR’s Office of Realty and Environmental Planning, the Illinois Natural History Survey, State Geological Survey, State Water Survey, Illinois State Museum, and Illinois Waste Management and Research Center.

Ecosystem Monitoring
CTAP monitors the condition of forests, wetlands, grasslands, and streams throughout the state. These data provide a baseline from which we can compare regional and site-specific patterns and assess changes in ecological conditions. Data is collected by professional scientists at the Illinois Natural History Survey (INHS).

CTAP professional scientists monitor 600 randomly-selected sites in each of the four habitats (150 of each; 30 sites per habitat per year) on both public and private land. In forests, wetlands, and grasslands data on herbaceous and woody vegetation, bird, and insect data are collected. They measure ecological indicators such as the presence of threatened and endangered species, species richness, species diversity, and dominance of native vs. non-native species. In streams, aquatic insects are the primary assemblage used as indicators of condition.

Data collected by CTAP scientists provide a snapshot of the quality and quantity of our ecosystems. This information is vital to protecting, preserving and enhancing Illinois forests, wetlands, grasslands, and streams.

CTAP Links

The Changing Illinois Environment: Critical Trends (1994)

Illinois Land Cover: An Atlas (1995)

Land Cover of Illinois 1999 - 2000 (2001)

Inventory of Resource Rich Areas in Illinois (1996)

Critical Trends in Illinois Ecosystems (2001)

CTAP 2001 Report

CTAP 2002 Report

Invasive Plants in Illinois Forests (2003)

CTAP on-line data

CTAP 2003/2004 Annual Report (2.52 mb Acrobat file)




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