Transactions of the Illinois State Academy of Science [Volume 111 (2018)]
Abundance, Volume and Distribution of Large Woody Debris along a Northeastern Illinois Stream
Authors: Xiaoyong Chen and Mary Carrington (111-05MS2663)
In-stream large woody debris (LWD), defined as dead wood ≥ 10 cm in diameter and ≥ 1 m in length, has played multiple structural and functional roles in aquatic ecosystems. Despite the importance of LWD to fluvial ecosystems, few studies have been conducted in low-gradient Midwestern rivers and streams. In this study, the quantity and characteristics of LWD were investigated in the upper-, middle- and down-stream sections along Thorn Creek located in Northeastern Illinois. The results showed that LWD abundance ranged from 18 to 58 pieces . 100 m-1, LWD volume ranged from 1.87 to 5.37 m3 . 100 m-2, and total LWD length ranged from 44.2 to 170.0 m per 100 m of stream length in the study sites. The quantity of woody pieces per 100 m of stream length was significantly higher in the down- stream section than in both upper- and middle-stream sections. Over 80% of LWD pieces were ≤ 20 cm in diameter and ≤ 4 m in length. Approximately 90% of wood pieces were in the medium and latter decomposition stages. Most LWD pieces (> 60%) were parallel to the stream-flow in the upper- and middle-stream sections and this percentage decreased to about 50% in the down-stream section. About 50% of wood pieces were located on the streambed and over 10% of LWD entirely spanned the bankfull width in both the upper-stream and middle-stream sections, but these fractions were 60% and 4% in the down-stream section. The highest proportion of LWD was anchored or buried in one streambank in both upper-stream and middle-stream sections, while the highest percentage of LWD was loose within the stream bankfull width in the down-stream section. About 60% of LWD played a functional role in bank stability, pool creation, sediment deposition and trapping smaller woody debris in the study stream and this percentage declined slightly from upper-stream to down-stream. Our results highlight the heterogeneity of LWD distribution in the study region.
Using Measured Hydrology and Vegetation Performance from a Reference Natural Area to Design Wetland Restoration Plant Communities in the Soil Saturation Zone: West Chicago Prairie Nature Preserve, DuPage County, IL
Authors: Steven I. Apfelbaum, Scott Kobal, Rachel Reklau, and Wayne A Lampa (111-04MS2290)
The protection of West Chicago Prairie State Nature Preserve has served as an important reference area for the measurement of wetland hydrology and vegetation systems relations. Measured shallow surface and subsurface hydrology data were not readily available regionally for use in the design of wetland restorations. This lack of data has contributed to designs in midwestern prairie landscapes favoring emergent and aquatic wetland types rather than the historically prevalent sedge meadows and wet prairie ecosystem types. In the absence of data, regulatory guidance has not been sufficient to understand the water depths and durations to meet hydrology criteria for wetland types that may experience shallow, short-duration, spring-growing season inundation, then quickly dry down but remain saturated during most of the growing season. Many zone-of-saturation wetland restorations have failed as a result. The purpose of this paper is to provide hydrology depth/duration data correlated with wetland ecosystem types from a reference area nature preserve to help guide future restoration designs.
This paper evaluates shallow ground-water well data for six years, from wells distributed along replicated parallel transects, located to integrate vegetation community mapping that includes upland bur oak savannas, through increasingly lower elevations along each transect that sequentially encountered mesic prairie, wet mesic prairie, wet prairie, sedge meadow, and emergent and aquatic wetlands. The study was conducted in the West Chicago Prairie, a dedicated Illinois Nature Preserve. The water depth was measured weekly at shallow water wells that provided the correlation between vegetation and water depth and duration.
The Army Corps of Engineers regulatory criteria for what constitutes successful wetland mitigation requires wetland restorations to have water levels within 30.5 cm of the ground surface for 12.5% of the growing season (or 23 consecutive days) in all wetland ecosystem types. We found that only emergent and aquatic communities in one of the highest quality natural areas in Chicago region—West Chicago Prairie, would meet this criterion. Sedge meadows and wet prairie only achieved this criterion for 4-7 days annually. This criterion favors deeper water and perpetually inundated wetland types over once prevalent sedge meadow and wet prairie ecosystems that seasonally dried down. Hydrologic criteria currently in use for determining successful wetland restoration are not applicable to higher elevation wetlands in the soil saturation zone. These systems cannot be restored using the current standard, as even these ecosystems in West Chicago Prairie Nature Preserve do not meet the U. S. Army Corps of Engineers (USACE) hydrology criterion.
Alignment of performance criteria with measured reference natural area vegetation and hydrology relationships from the West Chicago Prairie Nature Preserve, can be used to refine wetland mitigation designs and performance standards for the Chicago region. The same type of data and analysis would be required for the refinement of criteria in other regions of the USA and perhaps elsewhere.
Vegetation of Tomlinson Pioneer Cemetery Prairie Nature Preserve, Champaign County, Illinois
Authors: James L. Ellis and Kevin J. Wolz (111-03MS1057)
Tomlinson Pioneer Cemetery Prairie Nature Preserve, located in Champaign County, Illinois, USA, is a 0.4 ha savanna remnant. This plant community type was once common across central Illinois. During the 2013 growing season, we visited the site to record vascular plant species present. We also conducted a quantitative vegetation survey late in the growing season to determine species composition. From these surveys measures of floristic conservation value were calculated including the Floristic Quality Index (I), Shannon diversity index (H’), and Effective Species Richness. A total of 125 vascular plant species were found comprised of 87 species of dicots and 38 species of monocots. Twenty-two non-native species were found comprising about 17% of the site flora. Dominant species were Helianthus hirsutus and Poa pratensis followed by Corylus americana, Andropogon gerardii, and Sorghastrum nutans. The site had an I value of 32.7, an H’ of 3.3, and Effective Species Richness of 27.1. Species richness and diversity is comparable to prairie and savanna remnants in the region but floristic conservation value is slightly lower due to relatively high presence of non-native species. Continued management to control unwanted woody and non-native plant species is recommended to maintain the uncommon vegetation community at this site.
Distribution of the Smooth Softshell (Apalone mutica) in Illinois
Authors: Robert D. Bluett and Aaron C. Gooley (111-02MS2167)
We documented occurrences of the Midland Smooth Softshell (Apalone mutica) in Illinois by sampling 22 reaches on 14 rivers with potentially suitable habitat (i.e., within the species’ presumed range and with stream orders ≥6). During 2007 through 2017, we accrued 796 trap-nights of effort with baited hoop nets. Nine species were represented in 4,974 captures of turtles. Captures of Red-eared Slider (Trachemys scripta elegans) were most common (n = 3,911), followed by Spiny Softshell (A. spinifera; n = 731) and Smooth Softshell (n = 124). Captures of A. mutica documented its presence in 9 of 11 rivers with historical records and 1 of 3 without (the Spoon River). Another study documented presence of A. mutica in the Big Muddy River, for a total of 11 rivers with recent records. Occurrences suggest the Smooth Softshell’s distribution in Illinois is the same as or substantially similar to historical times. Using stream order to target sampling efforts was a good strategy, but might be improved with refinements. Our findings and those of other recent studies can inform decisions about the legal status of A. mutica in Illinois by addressing official thresholds for endangered, threatened, and secure.
Current Distribution of Crawfish Frogs in Southernmost Illinois
Author: John G. Palis (111-01MS2156)
Crawfish Frogs (Rana areolata [Lithobates areolatus]) are secretive, fossorial anurans that inhabit crawfish burrows in grass-dominated habitats. They are of conservation concern throughout their range, especially east of the Mississippi River. Crawfish Frogs occur throughout much of the southern half of Illinois where many county occurrence records are decades old and where their current conservation status requires confirmation. I surveyed for the presence of Crawfish Frogs from 2006-2017 to estimate their current distribution in the 11 southernmost counties of Illinois. I detected Crawfish Frogs at 187 locations in 10 counties. Despite extensive habitat loss, Crawfish Frogs are currently widely distributed across southernmost Illinois and appear to be secure at this time. However, ongoing habitat alterations threaten the future of Crawfish Frog populations in the region; therefore, I encourage prompt, proactive conservation efforts while Crawfish Frogs are still relatively common.