Illinois Natural History Survey - University of Illinois


Brenda Molano-Flores


The Critical Trends Assessment Program (CTAP) is a long-term endeavor to monitor the condition of forests, wetlands, grasslands, and streams throughout the state of Illinois. The main purpose of conducting this project is to assess long-term changes in ecological conditions as well as to serve as a baseline from which to compare regional and site-specific patterns throughout Illinois. This program is unique because it is the first-ever attempt at a comprehensive assessment of the Illinois environment undertaken by state natural resource organizations.

A total of 600 sites representing 4 habitats (150 of each; 30 sites per habitat per year) have been randomly selected from across the state on both public and private land. Since 1997 the CTAP professional scientists of the INHS have been conducting the monitoring at these sites. As of this fall we have monitored 103 forest, 108 wetland, 98 grassland, and 150 stream sites. In forests, wetlands, and grasslands, data on herbaceous and woody vegetation, birds, and insects are collected. For each of these groups we measure among other things species richness, diversity, and dominance of native versus non-native, and threatened and endangered species. In the case of birds, we are also collecting data on cowbird parasitism. For streams we have gathered information on all species of fishes and for the insects groups known as mayflies, stoneflies, and caddisflies. In addition a Macroinvertebrate Biotic Index (MBI) and Index of Biotic Integrity (IBI) is determined for each stream. Each of these sites will be revisited every five years. It is this five-year cycle for many years to come that is going to provide an understanding of the quality and quantity of our habitats.

It should be pointed out that the success of CTAP data collection depends on a cooperative effort between INHS professionals and EcoWatch citizen scientists. EcoWatch citizen scientists are part of the Illinois EcoWatch Network (RiverWatch, ForestWatch, PrairieWatch, and UrbanWatch), a statewide volunteer monitoring initiative collecting scientific data on Illinois rivers, forests, prairies, and urban green spaces. Protocols for this sister program are complementary to those of the professional scientists. The INHS professional scientists conduct detailed surveys at each habitat whereas the EcoWatch citizen scientists conduct a subset of procedures done by the professionals, but with less taxonomic resolution, at random and from volunteer-chosen locations. The combination of both data sets will allow us to have a better understanding about the quality and quantity of our habitats statewide.

Finally, the ultimate goal of CTAP is that the data gathered by INHS professionals and EcoWatch citizens will help scientists, local groups, lawmakers, state and federal agencies, and citizens in general to make better management, conservation, and policy making decisions regarding Illinois' forests, wetlands, grasslands, and streams. Additional information about CTAP and EcoWatch can be found in the following Web pages:

Using CTAP Professional Monitoring Sites to Test Floristic Quality Assessment For the Forests, Wetlands, and Grasslands of Illinois



Scientists, regulators, legislators, consultants, land managers, environmental professionals, not-for profit groups, and the general public have expressed a need for methods to assess and quantify the quality of natural areas. Additionally, they have looked for a means to identify pre-settlement habitat remnants, compare the floristic quality of different sites, and monitor the success of restoration efforts. Floristic Quality Assessment (FQA) was developed as a means of rapidly assessing the ecological integrity of natural areas. The original goals of this FQA were to identify high-quality natural areas, to compare floristic quality among sites regardless of community type, to monitor natural areas, and to track the success of restoration activities. FQA has become a popular tool recently to accomplish these goals. Floristic Quality Assessment utilizes coefficients of conservatism values (CC) assigned to plants in a region to obtain a Floristic Quality Index (FQI) for a given land area. To date we know of only a few studies that have tested the objectivity and utility of floristic quality assessment. In addition to the FQI, in Illinois identifying and ranking high-quality natural areas has followed the Illinois Natural Areas Inventory (INAI) criteria, which are on all counts a highly subjective and unrepeatable system for classification. Major criticism of both FQI and INAI criteria to assess floristic quality in Illinois is increasing. In this study using CTAP vegetation data, I address several questions that may help improve the way areas are assessed to determine their floristic quality: Is there a better, rapid, objective method of assessment than FQA or the INAI grading system that should be used to assess floristic quality in Illinois? What are the shortcomings of FQA? And where is it appropriate to be used? Are there deficiencies inherent in CC values, which makes FQA inherently flawed? Using vegetation data from the Critical Trends Assessment Program, what does FQA tell us about a community? What is the quality of the vegetative communities in Illinois according to FQA values?

Summary of Stream Condition and Future Projects


Many Illinois streams have been straightened and deepened, had their local area tiled to improve drainage, and protective trees removed from their banks. These habitat alterations have led to increased water temperatures, dramatic fluctuations in runoff, and a drastic change in the food base from blown in tree leaves to that of algae. Consequently, up to 75% of all streams were rated only fair-to-poor in near-stream habitat quality. The consequences of this are that native fish and macroinvertebrate species have less suitable habitat on which to live and forage. Most streams also demonstrate current or past problems with organic enrichment, as determined by biotic indices that measure such pollution. Even those sites with relatively high scores for mayfly, stonefly, and caddisfly species richness still have biotic index scores indicating moderate levels of disturbance. The fish community in many CTAP streams was dominated by just 2 or 3 fish species, sometimes by 1 or more of the 15 introduced species found in the state. Regionally, some watersheds were better off than others, but none of the 10 Illinois Streams Information System watersheds ranked high on all stream quality indicators.

One current project using CTAP stream data involves the establishment of reference (least impaired) stream conditions within the greater Chicago area. Streams of highest quality in the region have been sampled and are being compared to CTAP data from random stream sites across the state and within the Chicago region. This work will culminate in some guidelines for evaluating stream condition within the Northeastern Morainal Natural Division of Illinois.

Comparisons Between Native and Non=native Plpant Taxa Across Illinois

Non-native species are an increasing problem across the state of Illinois. Either on purpose or by ignorance many of these species have been introduced. Because many of their natural enemies are not present, these non-native species spread without any control, invading our natural areas. In this project using CTAP data from forests, wetlands, and grasslands, we have been investigating how frequent non-native species are in these habitats. In addition, we are determining which portion (northern, central, and southern) of the state is affected the most by these non-native species. With four years of CTAP data we have been able to determine that forest sites have the highest species richness and FQI compared to wetland and grassland sites, and non-native species are the least dominant in forest sites and most dominant in grassland sites. Non-native species are more abundant in northern Illinois sites compared to central and southern Illinois. Across all sites, as non-natives become more dominant, total site diversity declines. Overall CTAP data show that non-native species are present in every habitat, are sometimes specific to a habitat, and may be distributed unequally within vegetation strata and regions of the state. The long-term monitoring being undertaken by CTAP will help determine the full impact of non-native plant species in Illinois.


The Effect of Patch Size, Degree of Isolation, and Habitat Quality on Bird Detection Rate in Forest, Wetlands, and Grasslands



Many bird species are declining over large segments of their ranges due to habitat loss, degradation, fragmentation, and cowbird parasitism. Using the bird data generated by CTAP, we want to determine how patch size and degree of isolation from a similar patch is affecting the detection rate (i.e., total number of times a given species is detected divided by total number of visited sites) of area-sensitive and habitat-dependent bird species in forest, wetland, and grassland sites. In addition, we want to determine how habitat quality, based on the vegetation data gathered at the sites, affects detection rate of bird species. So far, during 1997-2000, 110 forest, 109 wetland, and 97 grassland sites have been monitored. Overall, low detection rates for area-sensitive and habitat- dependent bird species have been found across all habitats. One of the greatest detection rates in forests was for Brown-headed Cowbirds, a nest parasite, at 76.3%. For grassland and forest species, the smaller a habitat patch becomes, the fewer area-sensitive species it supported. The low detection rates of area-sensitive species for all habitat types indicates the degraded and fragmented nature of those habitats.

CTAP Database

The Illinois Natural History Survey has set the centralization of CTAP data as a high priority. The INHS, using Illinois River Decision Support System (ILRDSS) funding, has provided a database manager, computers, software, space, and network administrative support for this purpose. These funds will be sufficient to begin the process of data centralization, but this is a large undertaking. Additional funds have been requested to add a database programmer and to purchase additional hardware and software to make a fully Web-compatible system. This database project will allow interested citizens, land managers, and politicians in the Illinois River basin and statewide to access the state's major source of standardized quantitative biological data in the Illinois Natural Resource Information Network (INRIN) (see, with appropriate links to the Web-based ILRDSS. It will allow them to easily understand trends in threats and recovery of ecosystems across Illinois, generate increased interest in the CTAP program, and help to provide timely information to environmental policy makers.

ForestWatch / CTAP Professional Comparison Study


The quality of the data collected by volunteers is always questioned. In the CTAP program, data collection is a combination of both CTAP-INHS professional and EcoWatch citizen scientists efforts. Without the help of these citizen scientists the sample size of the CTAP data set will be substantially reduced. To assure that data collected by citizen scientists in all EcoWatch programs is of equal quality to that of CTAP-INHS professional scientists, periodic data quality checks are conducted by EcoWatch staff and INHS professional scientists. For example, we have been able to show that in the RiverWatch program volunteers identify taxa to an 80% or greater accuracy rate. In this project we want to determine if both CTAP-INHS professional and ForestWatch (FW) citizen scientists obtain similar results when assessing forest plant community conditions. Comparison questions will be limited by the level of data collected by FW in comparison to CTAP. For example, comparisons are expected to be fairly comprehensive when examining the tree data but less useful when examining the shrub data since FW does not identify all shrub species. Secondarily, we will also examine volunteer accuracy rates for tree and shrub identification. In this study, 20 forest sites will be monitored by citizen scientists and CTAP-INHS professional scientists.


Comparison of volunteer stream monitoring data (Illinois RiverWatch program) to professional monitoring data (CTAP)
R.E. DeWalt

Illinois Natural History Survey

1816 South Oak Street, MC 652
Champaign, IL 61820

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