Northeastern Naturalist Vol. 22, No. 2 A. Hauk, S.A. Clark, K.W. McCravy, S.E. Jenkins, and C. Lydeard 2015 299 2015 NORTHEASTERN NATURALIST 22(2):299–306 A Survey of Terrestrial Gastropods of the Alice L. Kibbe Life Science Station in West-Central Illinois Andrea Hauk1, Stephanie A. Clark2, Kenneth W. McCravy1, Seán E. Jenkins1, and Charles Lydeard1,* Abstract - Terrestrial gastropods are vital components in terrestrial ecosystems and are thought to play a key role in litter decomposition and nutrient release in temperate and tropical forests. As part of an effort to expand our knowledge of gastropod diversity in west-central Illinois, we conducted a survey of terrestrial gastropods of the Alice L. Kibbe Life Science Station in west-central Illinois from April to May 2013. We sampled at 9 different sites within representative stands of 5 of the prevalent forest types at the station and documented a total of 20 species representing 11 families and 17 genera, including 12 new records for Hancock County. The Polygyridae was the most diverse family (7 species). Although this study sheds additional light on the terrestrial gastropod fauna of west-central Illinois, further surveys are needed to establish baseline data and assess future trends in response to habitat modification and climate change throughout t he region. Introduction Terrestrial gastropods are vital components in terrestrial ecosystems and are thought to play a key role in litter decomposition and nutrient release in temperate and tropical forests (Burch and Pearce 1990; Meyer et al. 2011, 2013). Although Hubricht (1985) provided distribution maps of the 523 native species and subspecies of terrestrial snails of the eastern US, gastropod diversity remains understudied in the west-central region of Illinois. From the mid-19th century to the first half of the 20th century, a number of local naturalists including W.W. Calkins, J. Wolf, W.A. Nason, J.H. Ferriss, A.A. Hinkley, and F.C. Baker (Baker 1939), were interested in Illinois mollusks. However, a search of the Field Museum of Natural History’s (Chicago, IL) collections from the mid-1940s to 1990s yielded very little evidence that mollusk surveys had occurred across Illinois. Few terrestrial mollusk records exist for Hancock County, as evidenced by the combined holdings of the Field Museum, the Illinois Natural History Survey, the Academy of Natural Sciences of Philadelphia (Philadelphia, PA), and the Carnegie Museum of Natural History (Pittsburgh, PA) for the past 160 years. Thus there is a need for more baseline data to assess how habitat modification and climate change influence distributions of taxa in the region. Waggoner et al. (2006), who conducted a survey of the Sipsey Wilderness Area within Bankhead National Forest in northwestern Alabama, mentioned the importance of building upon our baseline knowledge of molluscan faunas. Alabama is considered to be well sampled, malacologically; however, 1Department of Biological Sciences, Western Illinois University, One University Circle, Macomb, IL 61455. 26535 North Mozart Street, Chicago, IL 60645. *Corresponding author - c-lydeard@wiu.edu. Manuscript Editor: David Yozzo Northeastern Naturalist 300 A. Hauk, S.A. Clark, K.W. McCravy, S.E. Jenkins, and C. Lydeard 2015 Vol. 22, No. 2 Waggoner et al. (2006) found 50 species in 2 counties, representing 14 families and 30 genera, including 58 new county and 2 new state records. In order to provide important baseline data and extend our knowledge of the terrestrial gastropod fauna of Illinois, we conducted a survey of the terrestrial gastropods of the Alice L. Kibbe Life Science Station of Hancock County in westcentral Illinois. Study Area We conducted this study during April and May 2013 at the Alice L. Kibbe Life Science Station (40.37oN, 91.40oW) in Hancock County, IL (Fig. 1). The field station is composed of 167 ha owned by Western Illinois University surrounded by an additional 520 ha of land owned by the Illinois Department of Natural Resources. The station is a mosaic of different habitat types that include: mature upland Quercus (oak)–Carya (hickory) woodlands, mature floodplain forest, early successional forests, oak barrens, hill prairies, limestone bluffs, and restored tallgrass prairies. Our study sites were located within representative stands of the following dominant woodland habitat types: a xeric Quercus stellata Wangenh. (Post Oak)-dominated stand on a southern exposure, a mesic Quercus alba L. Figure 1. Map showing the locations of the 9 sample plots within the Alice L. Kibbe Life Science Station. The insert shows the location of the Station in Hancock County, IL. Northeastern Naturalist Vol. 22, No. 2 A. Hauk, S.A. Clark, K.W. McCravy, S.E. Jenkins, and C. Lydeard 2015 301 (White Oak)-dominated stand on a northeast-facing slope, an early successional Robinia pseudoacacia L. (Black Locust)-dominated forest, an Acer sachharum Marsh. (Sugar Maple) forested riparian terrace, and a xeric Post Oak barren with shallow soils over limestone bedrock. For the last 25 years, prescribed burning has been used to control invasive woody species, to enhance ground-flora diversity, and promote oak regeneration in the station’s oak woodland and barren communities. However, we specifically chose sites that represented the major forest types at the station but have the least-recent history of burning at the site. The oak woodland sites used in this study were last burned in 2004, and there are no records or onsite indications that the early successional forest, riparian terrace, or oak-barren sites have burned in the last 25 years. Materials and Methods We surveyed a total of nine 300-m2 geo-referenced plots for terrestrial gastropods (Fig. 1) between April and May 2013. Two of the plots were located on a xeric south-facing slope with an overstory dominated by Post Oak and White Oak. Another 4 plots were located on a mesic northeast-facing slope in a mature oak-hickory woodland dominated by White Oak. One plot was located in an early successional woodland with an overstory dominated by Black Locust. Other single plots were located in a riparian-terrace forest dominated by Sugar Maple and a Post Oak-dominated barren. To sample, we spent 2 person-hours per site searching for specimens on the ground, in the leaf litter, under the bark of logs, and on tree trunks. We also collected two ~10-L bags of leaf litter from different locations in each plot and sorted them in the laboratory by passing the litter through 2 sieves (6.3-mm and 1.6-mm diameter), after which we used a magnifying glass to search each layer for gastropods. We identified all shells to species using the keys provided in Burch (1962) and Pilsbry (1939, 1940, 1946, and 1948) and specimens in the mollusk collection of the Field Museum of Natural History. We deposited voucher specimens in the invertebrate collection of the Department of Biological Sciences, Western Illinois University, Macomb, IL, which has a long-term stable albeit modest invertebrate collection. We followed the taxonomic nomenclature of Emberton (1988, 1991), Schileyko (2002, 2003), and Turgeon et al. (1998). Results and Discussion We collected a total of 533 shells (n = 238 from visual search and n = 295 from leaf-litter sorting) representing 20 species (Table 1). The visual search yielded a total of 6 species that were predominantly large species like Mesodon thyroidus (White-lip Globe), Anguispira alternata (Flamed Disc), and Neohelix alleni (Western Whitelip) that were abundant on the forest floor and tree trunks (Table 1), while leaf-litter sorting yielded 20 species. We recorded a total of 12 new county records for Hancock County (Table 1) based on Hubricht (1985) and the collections of the Field Museum of Natural History, the Illinois Natural Northeastern Naturalist 302 A. Hauk, S.A. Clark, K.W. McCravy, S.E. Jenkins, and C. Lydeard 2015 Vol. 22, No. 2 Table 1. List of gastropod species collected and their sampling locations at the Alice L. Kibbe Life Science Station, Hancock Coounty, IL by family. Taxa marked with * are new county records. MOW1–4 = mesic oak woodland plots 1–4, XOW1–2 = xeric oak woodland plots 1–2, RT = riparian terrace plot, ES = early successional plot, BRNS = barrens plot; LL = leaf litter, and VIS = visual search. MOW1 MOW2 MOW3 MOW4 XOW1 XOW2 RT ES BRNS Total LL VIS LL VIS LL VIS LL VIS LL VIS LL VIS LL VIS LL VIS LL VIS LL VIS Discidae Anguispira alternata (Say) 0 1 0 2 0 2 0 1 8 0 13 7 3 0 24 13 Euconulidae Euconulus fulvus (Müller)* 1 0 1 0 Gastrodontidae Zonitoides arboreus (Say) 1 0 1 0 2 0 Haplotrematidae Haplotrema concavum (Say) 1 0 1 2 0 1 5 0 1 0 8 3 Helicodiscidae Helicodiscus cf parallelus (Say)* 1 0 2 0 2 0 5 0 Helicodiscus shimeki Hubricht* 1 0 1 0 Oxychilidae Glyphyalinia indentata (Say)* 7 0 1 0 8 0 16 0 Nesovitrea electrina (Gould)* 26 0 23 0 18 0 67 0 Polygyridae Euchemotrema fraternum (Say) 0 1 3 0 3 1 Euchemotrema leai (A. Binney)* 1 0 1 0 Mesodon thyroidus (Say) 1 27 2 5 4 103 0 32 0 7 0 10 8 4 8 23 23 211 Neohelix alleni (Sampson) 0 1 1 3 0 1 0 1 14 0 0 2 6 0 21 8 Patera pennsylvanica (Green) 8 0 8 0 Stenotrema barbatum (G.H. Clapp)* 4 0 1 0 5 0 Xolotrema fosteri (F.C. Baker) 4 0 3 0 7 0 Pristilomatidae Hawaiia minuscula (A. Binney)* 1 0 1 0 5 0 2 0 1 0 6 0 16 0 Punctidae Punctum minutissimum (I. Lea)* 1 0 1 0 2 0 Strobilopsidae Strobilops labyrinthica (Say)* 14 0 19 0 10 0 3 0 3 0 5 0 0 2 54 2 Vertiginidae Gastrocopta contracta (Say)* 14 0 8 0 1 0 2 0 1 0 26 0 Gastrocopta pentodon (Say)* 1 0 3 0 1 0 5 0 Totals 67 29 54 7 34 111 5 34 9 7 34 12 45 4 37 32 10 2 295 238 Northeastern Naturalist Vol. 22, No. 2 A. Hauk, S.A. Clark, K.W. McCravy, S.E. Jenkins, and C. Lydeard 2015 303 History Survey, the Academy of Natural Sciences of Philadelphia, and the Carnegie Museum of Natural History. We calculated the rank order for each species (Table 2). White-lip Globe, Nesovitrea electrina (Amber Glass), and Strobilops labyrinthica (Maze Pinecone) were ranked first, second, and third, respectively. Euconulus fulvus (Brown Hive), Euchemotrema leai (Lowland Pillsnail), and Helicodiscus shimeki (Temperate Coil) were represented by a single specimen and tied for the lowest rank. We documented many White-lip Globes, which we frequently observed crawling along the leaf litter and up tree trunks throughout the study site. The Polygyridae was the most diverse family and had 7 species present, both the Helicodiscidae and Vertiginidae had 2 species, and the rest of the families were each represented by a single species. The mesic oak woodland had the highest species richness (mean = 9 species) and the greatest snail abundance (Fig. 2). It is not surprising that we collected more specimens in the mesic habitats because it is fairly well established that more mesic microenvironments are more conducive to forest-dwelling snails (Burch and Pearce 1990). The riparian terrace and early successional sites were very similar to the mesic woodland sites in terms of their species richness and abundance. We documented the lowest snail abundance and diversity in the 2 driest habitat types—the xeric oak woodland and oak barrens. Table 2. List of gastropod species collected and their sampling locations at the Alice L. Kibbe Life Science Station, Hancock County, IL by rank order. MOW1–4 = mesic oak woodland plots 1–4, XOW1–2 = xeric oak woodland plots 1–2, RT = riparian terrace plot, ES = early successional plot, and BRNS = barrens plot MOW XOW 1 2 3 4 1 2 RT ES BRNS Total Mesodon thyroidus 28 7 107 32 7 10 12 31 234 Nesovitrea electrina 26 23 18 67 Strobilops labyrinthica 14 19 10 3 3 5 2 56 Anguispira alternata 1 2 2 1 8 20 3 37 Neohelix alleni 1 4 1 1 14 2 6 29 Gastrocopta contracta 14 8 1 2 1 26 Glyphyalinia indentata 7 1 8 16 Hawaiia minuscula 1 1 5 2 1 6 16 Haplotrema concavum 1 3 1 5 1 11 Patera pennsylvanica 8 8 Xolotrema fosteri 4 3 7 Gastrocopta pentodon 1 3 1 5 Helicodiscus cf parallelus 1 2 2 5 Stenotrema barbatum 4 1 5 Euchemotrema fraternum 1 3 4 Punctum minutissimum 1 1 2 Zonitoides arboreus 1 1 2 Euconulus fulvus 1 1 Euchemotrema leai 1 1 Helicodiscus shimeki 1 1 Totals 96 61 145 39 16 46 49 69 12 533 Northeastern Naturalist 304 A. Hauk, S.A. Clark, K.W. McCravy, S.E. Jenkins, and C. Lydeard 2015 Vol. 22, No. 2 Worldwide, nonmarine mollusks are one of the most imperiled groups of animals (Lydeard et al. 2004). Although none of the species we observed in the present study are considered threatened or endangered, it is important to establish baseline data to assess how future habitat modifications or climate change may alter their status or distribution. Only recently have temperate terrestrial snails been studied to determine if they are susceptible to climate change (Pearce and Paustian 2013). Terrestrial gastropods may attempt to disperse to more favorable habitats due to effects Figure 2. Species richness and abundance values (mean ± 1 SE) for land snails collected in nine 300-m2 plots located in representative stands of the dominant forest types at the Alice L. Kibbe Life Science Station, Hancock County, IL. MOW= mesic oak Woodland (n = 4), XOW = xeric oak woodland (n = 2), RT = riparian terrace (n = 1), ES = early successional (n = 1), and BRNS = barren (n = 1). Northeastern Naturalist Vol. 22, No. 2 A. Hauk, S.A. Clark, K.W. McCravy, S.E. Jenkins, and C. Lydeard 2015 305 of climate change (Pearce and Paustian 2013), but the lack of suitable forest habitat and the known turnover of forest and grassland faunas (Nekola 2003) may result in the extirpation of some forest populations. Monitoring programs should be established to increase knowledge of population status of terrestrial gastropods in Illinois. Acknowledgments The authors wish to acknowledge the Alice L. Kibbe Life Science Station and its staff for providing support and for the use of the station equipment during the study. We would also like to thank Jeffery Woodyatt for his assistance during field sampling. 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