Transactions of the State Academy of Science received 5/20/20 (2020) Volume 113, pp. 41-45 accepted 9/29/20

Distribution and Habitat Analyses of American Badgers (Taxidea taxus) and Plains Pocket ( bursarius) in McLean County, Illinois

Alexander H. Palacios1, Oscar A. Schmidt1, Jack T. McKermitt1, Noah T. Haskin1, Angelo P. Capparella2, R. Given Harper1* 1Department of Biology, Illinois Wesleyan University, Bloomington, IL 61701 2School of Biological Sciences, Illinois State University, Normal, IL 61790 *Correspondence: [email protected]

ABSTRACT

Despite the loss of prairie habitat, fossorial species such as the (Taxidea taxus) and the Plains Pocket (Geomys bursarius) still persist in intensive agricultural landscapes in the Midwestern U.S. We determined the dis- tribution of the two species in McLean County, Illinois via roadside automobile surveys in 2017 and 2018. We detected 88 badger burrows (0.09 burrows/km) in 18 of 30 townships, mostly in central, southern and eastern McLean County. Based on home range size from previous studies, we estimated a minimum of 5 and a maximum of 9 badgers inhabited the bur- rows. Likewise, we recorded 245 pocket gopher mounds in 16 mound clusters (15.31 mounds/cluster; 0.02 clusters/km) in 5 of 30 townships in central and eastern McLean County. There was no significant difference in the amount of hay/pasture within the home ranges of badgers versus in random locations, and for both species there were no significant effects of soil type, distance to railroad rights-of-way, and distance to habitat along streams. Populations and distributions of both species are likely limited by the lack of grassland habitat in the county and could be below minimum viable population size.

Keywords: American Badger, Taxidea taxus, Plains Pocket Gopher, Geomys bursarius, McLean County, Illinois, distribution

INTRODUCTION American Badgers and Plains Pock- We determined the distribution and About 60% of Illinois consisted of prai- et Gophers are fossorial, prairie-de- possible habitat associations of both rie prior to Euro-American settlement pendent that historically species via roadside automobile sur- in the early 1800s, but less than 0.01% occurred in McLean County, Illinois. veys of badger burrows and pocket remained by the early 1900s, the rest Kennicott (1858) and Hoffmeister gopher mounds. Badger burrows and of the landscape largely replaced by (1989) indicated that badgers were pocket gopher mounds are often seen agriculture (Iverson 1988). Farming present in central Illinois in the mid- along roadsides in Illinois (Hoffmi- practices also changed in Illinois be- 1800s. Ver Steeg and Warner (2000) ester 1989, Mohr and Mohr 1936), and ginning in the 1950s, which greatly surveyed records of badger sightings badgers are attracted to roadside grass reduced the amount of hay land (and throughout Illinois, and confirmed that strips that provide habitat for their pastures) throughout the state (Walk et badgers were present in McLean Coun- prey (Klafki 2014). No recent studies al. 2010). Today, approximately 82% of ty, Illinois prior to 1900, and between have been conducted on either species McLean County, Illinois is composed 1951 - 1977; however, they indicated in McLean County, and such data can of row-crop agriculture, which consists that badgers were not reported be- provide insight as to how these organ- predominantly of corn (Zea mays) and tween 1900 - 1950, which they attribut- isms are persisting in major human-al- soybeans (Glycine max) (USDA 2017), ed to inadequate assessment records. tered landscapes within their historic while grasslands are mostly narrow Plains Pocket Gophers, which are home range. strips of non-native grasses between found in Illinois in a narrow band east METHODS roads and agriculture fields. The loss and south of the Illinois and Kankakee Rivers (Hoffmeister 1989), were docu- Automobile surveys for badger bur- of prairie has contributed to steep de- rows and pocket gopher mounds were clines in the populations of prairie-de- mented in central Illinois in the mid- 1800s (Baird 1857, Kennicott 1858), and conducted from September - Novem- pendent species (e.g., Pergams and Ny- ber 2017 and from March - November berg 2001, Bellar and Maccarone 2002). in McLean County in the early 1930s (Komarek and Spencer 1931, Mohr 2018, when both species were active. Despite these declines, both American Automobile surveys, which allow a Badgers (Taxidea taxus) (Duquette et al. 1935, Mohr and Mohr 1936). Today, badgers are ubiquitous in Illinois (Ver large area to be surveyed in a short 2014) and Plains Pocket Gophers (Geo- time period, have been used in other mys bursarius) (Hoffman and Choate Steeg and Warner 2000), while pocket gophers are common in regions of gla- studies to determine the distributions 2008) still persist in heavily agricultur- of both species (e.g., Berkley and John- al landscapes. cial outwash plains in the state with sandy soil (Tucker et al. 2014). son 1998, Quinn et al. 2010, Proulix and Distribution and Habitat Analyses of American Badgers and Plains Pocket Gophers in McLean County, Illinois 42 Alexander H. Palacios, Oscar A. Schmidt, Jack T. McKermitt, Noah T. Haskin, Angelo P. Capparella, R. Given Harper

MacKenzie 2012). Our surveys, which totaled 1030.79 km, were conducted by two teams of two individuals per ve- hicle, and each member of these teams remained either an observer or a driver for the duration of the study. During the surveys, which were conducted while travelling from 24 - 32 km/hr, the observer scanned both sides of the road for badger burrows and pocket gopher mounds. The surveys were performed in each of the 30 townships within Mc- Lean County, Illinois. Only secondary, bituminous roads were selected, such that equal numbers of zonal and me- ridional roads were surveyed in each township (Figure 1). Primary roads with higher traffic volume and higher speed limits were avoided for safety reasons. Roads along which roadside vegetation may have obscured bur- rows or mounds were surveyed on a later date after the vegetation died back or had been mowed. We recorded the GPS location when badger burrows or pocket gopher mounds were ob- served. GPS coordinates were initially Figure 1. American Badger burrows and Plains Pocket Gopher mounds observed determined via cell phones using the in McLean County, IL from September - November 2017, and March - November app GPS Status (MobiWIA), and the 2018. accuracy of these GPS coordinates was later verified with a Garmin GPS MAP 64s receiver. lar-shaped or were connected by raised 9.61 km2, respectively. To estimate the We identified burrows and mounds of tunnels visible above ground were as- maximum number of badgers inhab- both species based on criteria of pre- sumed to be created by Eastern Moles iting the burrows, we considered all (Scalopus aquaticus) (Hoffmeister 1989) burrows within a radius of 1.26 km (5 vious studies. American Badgers dig 2 burrows that have an entrance wider and were not counted. km ) as made by the same individual. than high (Hoffmeister 1989), with the Conversely, to estimate the minimum In analyzing the data, the following in- number of badgers inhabiting the bur- topsoil piled around it in a fan-shaped formation was used in determining the deposit (Eldridge 2004). A burrow was rows, we considered all burrows that home ranges of both species. Both male had overlapping 5 km2 home ranges as counted only if it was ≥ 50 cm deep and female badgers excavate multiple because Lay (2008) considered exca- made by the same individual. In ana- burrows in a year (Hoffmeister 1989). lyzing data for pocket gophers, a pock- vations < 50 cm deep to be “diggings.” Because multiple burrows in an area Badger burrows were distinguished et gopher mound cluster was defined were likely made by the same badger, as a group of mounds within an area from Woodchuck (Marmota monax) bur- in our analysis of the amount of hay/ rows in that badger burrows are much equal to a pocket gopher’s home range pasture surrounding a badger burrow, of 66 m2 (Zinnel 1992). A single pock- wider and more fan-shaped (Grizzell we only considered burrow locations 1955). Burrows that were dug straight et gopher typically occupies a burrow that represented the central-most bur- system with multiple mounds (Hoff- down or had soil that came out of the 2 row within a home range of a 5 km meister 1989). hole in a narrow cone were assumed to circle (radius = 1.26 km) of multiple be excavated by mammals other than burrows (n = 5 burrows for all spatial Spatial analyses were performed using badgers and were not counted. In con- analyses). We based our estimates of Arcmap 10.5, with land cover data from trast, pocket gopher excavations have home range on a study in an intensive 2011. The following spatial analyses a characteristic triangular, or deltaic, agricultural landscape in Ohio, where were conducted for each species: the shaped mound with a round patch of Duquette et al. (2014) reported that amount of hay/pasture within a home soil located at the apex (Quinn et al. male and female badgers had year- range (for badgers only); the soil type 2010). Mounds that were not triangu- ly mean home ranges of 2.40 km2 and (Type A = silt loam and Type B = silty- Distribution and Habitat Analyses of American Badgers and Plains Pocket Gophers in McLean County, Illinois 43 Alexander H. Palacios, Oscar A. Schmidt, Jack T. McKermitt, Noah T. Haskin, Angelo P. Capparella, R. Given Harper

clay loam) in which burrows/mounds (265.90 ± 307.10 ha; n = 10; t13 = 0.26, P its the population growth of badgers, were located; distances to railroad = 0.64). Likewise, there were no signif- which has likely occurred in McLean rights-of-way; distances to streams. icant differences in the mean distances County. Badgers also suffer mortality We considered railroad rights-of-way of badger burrows versus randomly when crossing roads (Hoodicoff et al. as they may contain remnant prairie selected locations to railroad rights- 2009, Sunga et al. 2017), and we doc- and grassland habitat (Bacone and of-way (t27.77 = -0.06, n = 25, P = 0.95) umented one road-killed badger on

Harty 1981), whereas streams are often or streams (t28= 0.82, n = 25, P = 0.42). 6 July 2018 in Dry Grove Township. bordered by grass or forested habitat. There was no significant difference in However, no badger burrows were ob- To provide comparisons, we collected the frequencies of soil type where bad- served in that immediate area. similar data for each species from ran- ger burrows were located versus at 2 The roadside, grassy strips that were domly selected locations chosen via randomly selected locations (χ 1 = 0.26, adjacent to agricultural fields and grass ArcMap. No badger burrows or pocket P = 0.61). swales along waterways likely provid- gopher mounds were identified with- We recorded 245 pocket gopher ed habitat for small that are the in the simulated home ranges around mounds in 16 mound clusters (15.31 primary prey of badgers. Spanel and these randomly-selected locations. mounds/cluster; 0.02 clusters/km) in 5 Geluso (2018) found that voles and mice Statistical analyses were conducted of 30 townships in central and eastern were prevalent in roadside ditches in using SPSS 25 (IBM SPSS Statistics McLean County (Figure 1). There were . In addition, small amphibi- 2018). We used t-tests to compare no significant differences in the mean ans may breed in pools of water along the mean number of hectares of hay/ distances of mound clusters (n = 16 for roadsides (Thurow 1999), and badgers pasture within 5 km2 circles around all analyses) versus randomly select- may also prey upon them (Tumlison badger burrow locations compared to ed locations (n = 25 for all analyses) to and Surf 2016). However, because the within 5 km2 circles around randomly railroad rights-of-way (t38.80 = -0.56, P = grass strips adjacent to roads in our selected locations. We also used t-tests 0.58) or streams (t39 = -0.59, P = 0.56). In study area were narrow (6.48 ± 2.10 m to compare the mean distance of bad- addition, there was no significant dif- width; n = 98 strips), and grass swales ger burrows versus random locations ference in the frequencies of soil type along waterways were not abundant, it to railroad rights-of-way and streams, where mound clusters were located is unlikely that badgers could find suf- versus the soil type at randomly select- ficient prey in these habitats alone to and a chi-square test to compare soil 2 types of badger burrow locations ver- ed locations (χ1 = 2.17, P = 0.14). meet their dietary needs. Agricultural sus random locations. The same statis- DISCUSSION fields may also provide habitat for ro- dents, but tillage practices have a major tical tests were also used for the pocket There was a very low density of badger gopher mound cluster analyses, with impact on abundance (Duquette burrows in all county townships, likely et al. 2014). In 2017, 64% of agricultural the exception of the analysis for hay/ due to the paucity of grassland habitat pasture. Some of the data for both fields in central Illinois were tilled via present in the county. In 2017, hay/pas- intensive or reduced tilling practices species did not meet the assumption ture comprised only 0.5% of McLean of a normal distribution; however, the (USDA 2017). Berl et al. (2017) found County (USDA 2017). Our results are an average density of 14.1 individuals/ outcomes of all parametric tests did similar to those found by Proulix and not differ from those via nonparamet- ha of prairie deer mice (Peromyscus ma- MacKenzie (2012) in southwest Sas- niculatus bairdii) in in reduced ric statistical analyses (analyses not katchewan (mean density of 0.11 bad- shown). tillage row-crop agricultural areas with gers/km of road), and by Berkley and no post-harvest tillage. It is also like- RESULTS Johnson (1998), who found that bad- ly that tilling practices disrupt badger gers were uncommon in most regions We found 88 badger burrows (0.09 burrowing sites (Duquette et al. 2014), of Indiana, which also is dominated by and the disruption of natal burrows burrows/km) in 18 of 30 townships, intensive row-crop agriculture. The mostly in central, southern and eastern could negatively impact badger popu- lack of statistical significance for bad- lations. McLean County (Figure 1). No living gers in relation to all habitat character- badgers were observed during any istics that we measured is likely due to Likewise, we found very low densi- of the surveys. Based on home range the low density of badger burrows that ties of Plains Pocket Gophers, and all size, we estimated a minimum of 5 and we observed. Duquette et al. (2014) of the mounds were found in the cen- a maximum of 9 badgers inhabited the found that badgers in west-central Illi- tral and eastern portions of the county. burrows. There was no significant dif- nois and Ohio had larger home ranges Because a single pocket gopher typi- ference in the mean number of hectares cally occupies a burrow system with 2 compared to those in the western U.S., of hay/pasture within 5 km circles which they attributed to greater habitat multiple mounds (Hoffmeister 1989), around badger den locations (339.40 fragmentation that required badgers to the mound clusters we observed like- ± 208.29 ha; x + SD; n = 5) compared ly represent only 16 individuals, which 2 move longer distances to find mates to hay/pasture̅ within 5 km circles and acquire food. They also indicat- represent a relictual population in the around randomly selected locations ed that agricultural development lim- county. Unlike badgers that can uti- Distribution and Habitat Analyses of American Badgers and Plains Pocket Gophers in McLean County, Illinois 44 Alexander H. Palacios, Oscar A. Schmidt, Jack T. McKermitt, Noah T. Haskin, Angelo P. Capparella, R. Given Harper lize and disperse over intensive agri- hindered our ability to observe them. herty, and R.K. Swihart. 2017. Winter pref- cultural landscapes, pocket gophers However, we believe this is unlikely, erence for weed seed and waste grain by cannot easily do so, as there is likely as when areas with taller vegetation native mice in row-crop agriculture. Weed little available food and their burrows were noted, they were surveyed at Science 65:406-412. Bohlin, R.G. and E.G. Zimmerman. 1982. would be disrupted by tilling practices. later dates when the vegetation had Genic differentiation of two chromosome Hoffman et al. (2007) found that Plains either been mowed or had died back. races of the Geomys bursarius complex. Pocket Gophers in were unable Finally, during our surveys we did not Journal of Mammalogy 63:218-228. to inhabit areas that were harvested differentiate recent from older badger Crooks, K.R. 2002. Relative sensitivities of and tilled annually, because such land- burrows. mammalian carnivores to habitat frag- use practices destabilize habitats and The results of our study suggest that mentation. Conservation Biology, 16:488- eliminate both refugia and dispersal 502. both badgers and pocket gophers have Duquette, J.F., S.D. Gehrt, V.S. Barbara, and corridors. It is also likely that roads and small populations in McLean Coun- major highways may impede pocket R.E. Warner. 2014. Badger (Taxidea taxus) ty. Similar findings for both species in resource selection and spatial ecology in gopher dispersal (Forman and Alexan- intensive agricultural landscapes have intensive agricultural landscapes. The der 1998, Quinn et al. 2010). Our find- been reported in other studies (e.g., American Midland Naturalist 171:116- ings are similar to those of Quinn et Berkley and Johnson 1998, Crooks 127. al. (2010), who found a declining geo- 2002, Quinn et al. 2010, Duquette 2014). Eldridge, D.J. 2004. Mounds of the Amer- graphic distribution and abundance The paucity of grassland habitat and ican badger (Taxidea taxus): significant of this species in Indiana. The abun- increased habitat fragmentation from features of North American shrub-steppe dance of pocket gophers in McLean ecosystems. Journal of Mammalogy agriculture and roads likely hinders 85:1060-1067. County is lower than that observed by the population expansion of both spe- Mohr (1935), who indicated they were Forman, R.T.T. and L.E. Alexander. 1998. cies in the county. A portion of eastern Roads and their major ecological effects. “common” in central Illinois based on McLean County is listed by the Illinois Annual Review of Ecology and Systemat- surveys conducted from 1930-1934. Department of Natural Resources as a ics 29:207-231. Mohr and Mohr (1936) documented priority area to expand grassland habi- Grizzell, R.A. 1955. A study of the southern five individual pocket gophers on 0.06 tat (Illinois Department of Natural Re- woodchuck, (Marmota monax monax). The ha of a 4-meter wide roadside non-na- sources 2016), which would likely ben- American Midland Naturalist 53: 257-293. tive grass strip in Woodford County, efit populations of both species. Hoodicoff, C. S., K.W. Larsen, and R.D. Illinois in 1935. Whereas small popu- Weir 2009. Home range size and attri- ACKNOWLEDGEMENTS lations of pocket gophers can persist butes for badgers (Taxidea taxus jeffersonii) and maintain genetic diversity (Bohlin This research was supported by the in south-central British Columbia, Can- ada. The American Midland Naturalist, and Zimmerman 1982), the low num- Beach Lewis fund from Illinois Wesley- 162:305-317. ber of individuals documented in our an University. Aaron Wilson provided Hoffman, J.D. and J.R. Choate. 2008.- Dis surveys suggest the population is be- advice for the GIS analyses. Two anon- tribution and status of the yellow-faced low a minimum viable size in McLean ymous reviewers provided useful com- pocket gopher in Kansas. Western North County due to the lack of habitat and ments on a draft of the manuscript. American Naturalist 68:483-492. the significant barriers to dispersal. LITERATURE CITED Hoffman, J.D., J.R. Choate, and R. Channell. 2007. Effects of land use and soil texture Bacone, J.A. and F.M. Harty. 1981. 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