We sampled freshwater mussels at 12 sites centered around three lowhead dams in the Vermilion River basin (Wabash River drainage) to address their effects on the freshwater mussel fauna and to obtain baseline data prior to their removal. Compared with reference sites, impounded areas and plunge zones had lower mussel abundance and extant species richness. We also examined literature accounts and museum collections to determine species distributions in the basin and compared those data to locations of the three dams and location of the former Homer Park Dam, which was removed over 50 years ago. Two species, Yellow Sandshell (Lampsilis teres) and the state-threatened Black Sandshell (Ligumia recta), are now found only downstream of the Danville Dam. Pimpleback (Amphinaias pustulosa) and Mapleleaf (Quadrula quadrula), which was found only downstream of the Homer Park Dam prior to 1950, has expanded its range upstream since the dam was removed. Data collected during this study contributes insights into the effects of lowhead dams on freshwater mussel abundance and species richness in Midwestern streams, and will be used as a baseline to compare to future post-dam removal collections.
Spring Cavefish ( Forbesichthys agassizii ) inhabit springs, streams and subterranean aquatic habitats from Missouri to Tennessee. In Illinois, most fisheries survey programs do not sample habitats in which Spring Cavefish can be found, and therefore, its distribution and ecology are poorly understood in the state. We reviewed records of the species within Illinois fisheries databases and museum collections and performed targeted surveys for the species in both 2003 and 2013 to better evaluate distribution status and trends. At a coarse spatial resolution, Spring Cavefish distribution appears stable; however, temporal variability in its presence at individual locations suggests the species may be vulnerable to local extirpation. Evaluation of environmental setting relative to Spring Cavefish distribution suggests water quality may influence presence more than physical characteristics. This study highlights the need for targeted surveys to monitor the status of this species.
A new record of the invasive stink bug Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), the brown marmorated stink bug (BMSB), is reported for McDonough County, in west-central Illinois. BMSB is known to cause severe damage to commodities in the Mid-Atlantic region of the U.S. Adults seek homes as overwintering sites and are a nuisance. Currently there are limited options to control BMSB and monitoring their presence and range extension can contribute to the development of pest management strategies. This represents one of the western-most records of this insect in Illinois. The current distribution and potential economic and ecological impacts of BMSB
The fecundity and annual survival of 26 marked white-tailed deer (Odocoileus virginianus) between 8 and 18 years old were examined on 2 areas in Illinois offering some refuge protection. These females, often dominant members within the deer social structure, were healthy and productive well into old age. Fawn production declined somewhat with age (P = 0.02), but regression analysis did not reveal an obvious inflection point. Female survival after age 8 was significantly lower than survival of these same these same females 3–7 years old on the same study areas. A regression curve indicated survival began a significant decline at about age 10.
Low and variable rates of capture are common problems when estimating abundance of freshwater turtles with capture-mark-recapture (CMR). We speculated camera traps would allow us to obtain reliable estimates of abundance by re-sighting marked Trachemys scripta elegans (Sliders) as they basked on man-made rafts during a 20-day surveillance period. We evaluated the method by releasing Sliders in a fenced enclosure to compare estimates from CMR to true abundance. We also evaluated probabilities of detection and retention of marks. Permanence of marks applied with marine epoxy satisfied assumptions for CMR. Camera traps detected 23 of 25 Sliders. Our ability to discern marks from photos was good (110 of 114 re-sightings). The proportion of marked Sliders detected per day was 0.22; detection varied with day of surveillance (1–20) and decreased with maximum air temperature the preceding day. All CMR models providing valid estimates of abundance included the true number of marked Sliders in their confidence intervals and yielded point estimates within 27% of the true value. An estimate of abundance from the top CMR model exceeded the true value by 22%, with a wide confidence interval. Model averaging improved the point estimate (17% over true) and produced a narrower confidence interval. A favorable comparison of estimated and true abundance validated camera traps as a tool for estimating abundance of adult Sliders. We believe camera traps could prove useful for detecting biases caused by primary methods of capture, refining estimates of abundance from other methods and collecting data at multiple locations consistently, simultaneously and frugally compared to manual methods alone.
Odonata (dragonflies and damselflies) play an important role in habitat management and conservation, but our understanding of the causes of commonness versus rarity in this group is limited. In this study we examined the causes of rarity for the Odonata of Illinois. Using S-ratings for conservation status and published habitat classifications for Illinois odonates, we investigated whether habitat type (lotic versus lentic) or habitat specificity (whether they were limited to a specific type of aquatic habitat) was related to commonness. We found that lotic species and habitat specialists were more likely to be rare than lentic and generalist species. More information, however, is needed on the distributions and natural histories of Illinois odonates if we are to more fully understand the causes of rarity in this important group.
Emigration behavior by female white-tailed deer (Odocoileus virginianus) is an important attribute of population dynamics in Illinois. The factors influencing the process of selecting a new home range are largely unknown, yet may affect hunting success, other interactions with human activities, and deer social behaviors. Twenty-five radio-marked dispersing (N = 14) and migrating (N = 11) female white-tailed deer (4 adults, 7 yearlings, 14 fawns when marked) were followed from 3 sites (2 in central and 1 in northern Illinois) to the home ranges selected for parturition and fawn rearing. Dispersing deer (i.e., those making one-way movements to a new home range) moved an average of 44.9 ± SE 6.4 km whereas migrators (i.e., those moving to a new range) moved 14.0 ± SE 7.2 km from their natal ranges. Females moved rapidly in nearly a straight line to their new home range readily crossing roads, rivers, and under high tension power lines on their journey. Females marked in east-central and northern Illinois where forest cover totaled <5% of the landscape, selected sites with greater forest cover, grasslands, forest patch size and density, and total patch richness than were available in random locations. Habitats selected by females in west-central Illinois where more forest cover was available did not differ from random sites. Parturition ranges (used May 15–July 15) at all 3 sites contained fewer houses and roads and more forest patches compared with the natal ranges and the larger new range (used May 15–October 1). Migrating females survived longer than dispersing females, but female life span and fawn survival were not significantly affected by the habitat composition of the new home ranges.
Low and variable rates of capture are chronic problems in chelonian studies. We conducted a pilot study to evaluate protocols for future inventories of turtles in Illinois by comparing capture efficiency and species coverage for 2 devices (hoop net and cage trap), baits (fresh and day-old fish), habitats (lentic and lotic) and time periods . We accrued 402 captures of 378 individuals representing 7 species. At Sanganois State Fish and Wildlife Area (Sanganois), hoop nets produced more captures of more species (n = 231; 6 species) than cage traps (n = 119; 4 species). Statistical tests were equivocal for a reach of the Sangamon River, where both devices had 26 captures but hoop nets detected more species (n = 6) than cage traps (n = 3). At Sanganois, catch per unit effort varied with sampling session (time) and freshness of baits; one measure of species coverage varied with session. Results helped us make informed decisions about protocols for future inventories.
In May 2004, a dead white-tailed deer (Odocoileus virginianus) radiocollared in 1991 was found in Carbondale, Illinois, and was aged at 16 years old via cementum annuli analysis. She was a member of an unharvested, free-ranging population and likely died of natural causes. Given the average longevity of deer in unharvested populations at about 8 years of age, our finding is quite rare. Increased longevity of deer can heighten lifetime reproductive output, which may contribute to elevated deer abundance and concentrated herbivory in urban settings. White-tailed deer are the most widespread and abundant cervid in North America (Demarais et al., 2000). When protected from human harvest, deer populations are capable of irruptive population growth given their relative longevity and high reproductive capacity (McCullough, 1979, 1997). Flower (1931) stated that deer of the genus Odocoileus have a mean life span of 8 years, 10 months and 6 days. Masters and Mathews (1990) recorded female whitetails surviving beyond 9 years and remaining reproductively active in an unhunted population. Relatively few records exist of free ranging whitetailed deer living >10 years (Ozoga, 1969). The oldest free-ranging deer with age determined from counts of cementum annuli was a 20-year-old female in New York state (Sauer, 1984). Thomas and Bandy (1973) analyzed teeth from 859 black-tailed deer (O. hemionus); their oldest animal was a 19.5-year-old female. Records of extreme longevity include accounts of captive females living to ages of 17-19 years (Rue, 1978). We are unaware of more recent reports of long-lived deer, especially in Midwestern North America. Herein, we report finding the remains of an old-aged female white-tailed deer from an unharvested population within the city limits of Carbondale, Illinois, <1 km north of Southern Illinois University Carbondale (SIUC) property. This deer was found by researchers during May 2004 while searching for fawns as part of another study (Rohm et al., 2007, 2008). Mortality of this individual had likely occurred during the winter months (but not earlier) given the stage of decomposition. No broken long bones indicative of trauma were noted, nor was hunting legal within city limits, thus, we concluded the animal likely died of natural causes (i.e., senescence). This deer was wearing a radiocollar
