Managers use latrine surveys to monitor swamp rabbit (Sylvilagus aquaticus) populations but may miss rabbits in sites lacking suitable latrine logs. We tested artificial latrine logs in logless thickets in southern Illinois, USA, generally detecting swamp rabbits in fewer visits than by live-trapping. Artificial logs can aid swamp rabbit monitoring, especially in logless habitats

Nielsen, Clayton K.

Rubert, Lyann

Scharine, Paul D.

Schauber, Eric M

Eric M. Schauber

Paul D. Scharine

Clayton K. Nielsen

Lyann Rubert

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An Artificial Latrine Log for Swamp Rabbit Studies

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Southern Illinois University CarbondaleOpenSIUCPublications Department of Zoology2-2008An Artificial Latrine Log for Swamp Rabbit StudiesEric M. SchauberSouthern Illinois University Carbondale, schauber@siu.eduPaul D. ScharineSouthern Illinois University CarbondaleClayton K. NielsenSouthern Illinois University CarbondaleLyann RubertSouthern Illinois University CarbondaleFollow this and additional works at: http://opensiuc.lib.siu.edu/zool_pubsThis is the peer reviewed version of the article cited below, which has been published in final form at10.2193/2007-234. This article may be used for non-commercial purposes in accordance with WileyTerms and Conditions for Self-Archiving.This Article is brought to you for free and open access by the Department of Zoology at OpenSIUC. It has been accepted for inclusion in Publicationsby an authorized administrator of OpenSIUC. For more information, please contact opensiuc@lib.siu.edu.Recommended CitationSchauber, Eric M., Scharine, Paul D., Nielsen, Clayton K. and Rubert, Lyann. "An Artificial Latrine Log for Swamp Rabbit Studies."Journal of Wildlife Management 72, No. 2 (Feb 2008): 561-563. doi:10.2193/2007-234.  1 25 October 2007 1 Eric M. Schauber 2 Cooperative Wildlife Research Laboratory 3 Southern Illinois University 4 Mailcode 6504 5 Carbondale, IL 62901 6 618-453-6940; FAX 618-453-6944; Email schauber@siu.edu 7 RH:  Artificial latrine log for swamp rabbits  Schauber et al. 8 An Artificial Latrine Log for Swamp Rabbit Studies 9 Eric M. Schauber,1  Cooperative Wildlife Research Laboratory and Department of Zoology, 10 Southern Illinois University, Carbondale, IL 62901 11 Paul D. Scharine, Cooperative Wildlife Research Laboratory and Department of Zoology, 12 Southern Illinois University, Carbondale, IL 62901 13 Clayton K. Nielsen, Cooperative Wildlife Research Laboratory, Southern Illinois University, 14 Carbondale, IL 62901 15 Lyann Rubert, Cooperative Wildlife Research Laboratory and Department of Zoology, Southern 16 Illinois University, Carbondale, IL 62901 17 ABSTRACT  Managers use latrine surveys to monitor swamp rabbit (Sylvilagus aquaticus) 18 populations, but may miss rabbits in sites lacking suitable latrine logs.  We tested artificial latrine 19 logs in logless thickets in southern Illinois, generally detecting swamp rabbits in fewer visits than 20 by live trapping.  Artificial logs can aid swamp rabbit monitoring, especially in logless habitats. 21 JOURNAL OF WILDLIFE MANAGEMENT 00(0):000-000; 2008 22 KEY WORDS  defecation, habitat, latrine, monitoring, presence-absence, survey, swamp rabbit, 23 Sylvilagus aquaticus 24 ------------------------------------------------------------------------------------------------------------ 25                                                       1 E-mail: schauber@siu.edu    2 The swamp rabbit (Sylvilagus aquaticus) is endemic to the southeastern United States and 26 typically inhabits bottomland hardwood forests with dense understory (Chapman and Feldhamer 27 1981, McCollum and Holler 1994).  Swamp rabbits are legal game animals in much of their 28 range, but their abundance and distribution have declined in some areas along the historic 29 northern range limit (Korte and Fredrickson 1977, Whitaker, Jr. and Abrell 1986, Kjolhaug et al. 30 1987).  Managers require information about abundance, distribution, and habitat associations of 31 the swamp rabbit for conservation purposes, but swamp rabbits are cryptic, inhabit dense cover, 32 and are difficult to live-trap.  Fortunately, swamp rabbits habitually defecate on elevated 33 substrates (especially logs), producing conspicuous latrines.  Zollner et al. (1996) found that 34 swamp rabbits deposited 91% of fecal pellets on logs and appeared to select broad, moss-covered 35 logs in advanced decay.  Latrines likely serve a social signaling function associated with 36 reproduction, although swamp rabbits may also defecate while using logs as elevated lookouts 37 (Whitaker, Jr. and Abrell 1986, Zollner et al. 1996).  Because pellet groups on elevated 38 substrates are visually obvious, surveying for latrines is easy, inexpensive, and frequently used to 39 monitor the local presence and abundance of swamp rabbits (Terrel 1972, Heuer, Jr. and Perry, 40 Jr. 1976, Wolff and Barbour 2002, Scheibe and Henson 2003). 41  Although latrine surveys are easy and inexpensive, they may fail to detect swamp rabbits 42 inhabiting areas that lack suitable latrine substrates.  Zollner et al. (2000) found that distribution 43 of latrines in areas inhabited by swamp rabbits was strongly correlated with presence of downed 44 logs.  Recently afforested areas (e.g., retired agricultural fields), however, likely provide dense 45 understory suitable for swamp rabbits’ habitation but lack logs or stumps suitable for fecal 46 deposition.  Our objective was to develop and field-test an artificial latrine log (ALL) to facilitate 47 latrine surveys for swamp rabbits in habitats lacking suitable latrine substrates. 48   3 STUDY AREA 49 Southern Illinois constitutes part of the northern limit of the swamp rabbit's historic range 50 (Kjolhaug et al. 1987).  Suitable swamp rabbit habitat comprised approximately 56,000 ha in 51 southern Illinois, mostly along the Mississippi, Ohio, Big Muddy, and Cache rivers (Woolf and 52 Barbour 2002).  We conducted research in selected patches of early-successional habitat in 53 Alexander, Pulaski, Johnson, and Union counties in southern Illinois.  We chose sites near 54 bottomland hardwood forest patches known to currently or historically maintain swamp rabbit 55 populations.  These sites had all been recently (i.e., within 15 yr) reverted from agricultural 56 production to federal farm programs (i.e., Wetlands Reserve Program) or otherwise managed for 57 early-successional habitat.  Given the recent agricultural use of these sites, no downed logs were 58 present for swamp rabbits to defecate upon.  Dominant overstory species were swamp white oak 59 (Quercus bicolor), pin oak (Q. palustris), red oak (Q. rubra), bald Cypress (Taxodium 60 distichum), sweetgum (Liquidambar styraciflua), and American sycamore (Platanus 61 occidentalis).  Understory species present included Allegheny blackberry (Rubus allegheniensis), 62 poison ivy (Toxicodendron radicans), broom sedge (Andropogon virginicus), goldenrod 63 (Solidago spp.), and various sedges (Carex spp. and Cyperus spp.).   64  65 METHODS 66 We constructed each ALL as a frame of 0.95-cm plywood with a rectangular piece of carpet 67 covering the top (Fig. 1A, B).  Carpet provided an absorbent substrate for scents, mimicking 68 moss, and also was springy because it was only supported by the perimeter of the frame over 69 most of its length.  The ALLs had flat tops, based on swamp rabbits' preference for large-70 diameter logs that provide relatively flat platforms.  To facilitate transport, we skeletonized the 71   4 frame to reduce weight and bound it loosely together with nylon cable ties (zip ties) looped 72 through holes in the plywood, allowing the frame to fold flat (Fig 1B).  Each ALL weighed 73 approximately 1.2 kg and measured 96  19 cm when collapsed.  In the field, we tightened and 74 trimmed the zip ties to make the frame rigid, then stapled the carpet on top.   75  We deployed 404 ALLs at 29 early-successional sites in southern Illinois (10-20 76 ALLs/site, 0.2-6.2 ALLs/ha) in November-December 2006.  These sites had dense woody 77 vegetation <10 cm diameter at breast height and were <2 km from sites where we had detected 78 swamp rabbit presence via surveying for latrines on existing logs.  We distributed ALLs within 79 each site to maximize coverage of suitable habitat but also placed them near obvious runways or 80 suspected swamp rabbit fecal pellets.  We examined ALLs for the appearance of swamp rabbit 81 fecal pellets 3-4 times between 26 January and 30 April 2007 at intervals of 12-45 days.  We 82 identified round fecal pellets on ALLs as swamp rabbit pellets based on size comparison with 83 eastern cottontail (S. floridanus) pellets (which are rarely found on natural logs) in sites inhabited 84 by both species.   85  We also set 8-20 Tomahawk live traps (1.5 kg, Model 205 Collapsible, Tomahawk Live 86 Trap Co., Tomahawk, WI) at each site (0.2-6.7 traps/ha) and checked them each morning for 87 periods of 8-14 days (sometimes shortened by flooding).  We baited each trap with apple, 88 covered it with burlap, and surrounded it with leaves and woody debris.  We identified captured 89 rabbits as swamp rabbits or eastern cottontails based on size and pelage coloration and marked 90 each rabbit with uniquely numbered ear tags (Model 1005-3, National Band and Tag Co., 91 Newport, KY; Southern Illinois University Institutional Animal Care and Use Committee 92 Protocol no. 06-035).  We compared efficiency of ALLs and live trapping for detecting swamp 93   5 rabbits by effort required for first detection (Foresman and Pearson 1998), measured in number 94 of visits to each site.  95  96 RESULTS  97 We captured swamp rabbits at 11 of 29 sites (38%) and swamp rabbits established latrines on 98 ALLs in 7 sites (24%), all sites where we captured swamp rabbits.  We captured 23 individual 99 swamp rabbits (<4 individuals/site) a total of 34 times in 4,741 trap-nights.  Percentage of ALLs 100 with swamp rabbit latrines increased over time (Fig. 2A), indicating that once swamp rabbits 101 began using a log they continued using it.  We detected swamp rabbits at more sites and in less 102 time (in days) via live trapping than via ALLs, because we trapped for <14 consecutive days per 103 site, but ALLs yielded lower effort to detection in terms of site visits (Fig. 2B) in all but 2 sites.  104 At the end of our study, latrine size ranged as high as 649 pellets on one ALL (median = 59 105 pellets/used ALL).  Our ALLs cost $1.62/ALL (approx. $700 total) in materials (we acquired 106 discarded carpet from installers at no cost) compared with $49/trap (>$3,000 total).  The ALLs 107 were still in good condition in April 2007, after >4 months in place, with the only apparent 108 problems being rodent damage to zip ties and some disruption by humans. 109  110 DISCUSSION  111 Managers monitoring cryptic species can benefit from methods that are inexpensive, efficient, 112 and convenient.  The ALLs we tested were less expensive and generally detected swamp rabbits 113 with less effort than live traps, although ALLs required more time for detection.  We also found 114 ALLs much more convenient to use because live traps must be checked at least daily (Animal 115   6 Care and Use Committee 1998), whereas ALLs can be checked months after deployment, with 116 greater detection probability the longer left in place.   117  Zollner et al. (2000) described swamp rabbits as one of the least-studied lagomorphs, 118 despite their abundance in many areas.  The paucity of research stems in part from swamp 119 rabbits' cryptic behavior and low trappability (Woolf and Barbour 2002, Watland et al. 2007).  120 Visual surveys for latrines have provided a useful tool for assessing status of swamp rabbit 121 populations and potential responses to habitat manipulation and other management actions, and 122 ALLs are likely to aid detecting swamp rabbits in habitats where latrine substrates are lacking.     123 Management Implications 124 Artificial latrine logs may expand the scope and flexibility of latrine surveys by increasing 125 sensitivity in areas lacking logs or other suitable latrine substrates, such as lands recently retired 126 from agricultural production. Such lands can be a substantial component of potential habitat for 127 swamp rabbits.  Managers seeking to quickly detect swamp rabbit presence in latrine-lacking 128 habitats should use intensive live trapping if money and person-power permit.  However, 129 managers may benefit by using artificial latrine logs when person-power or funds are limited, in 130 long-term monitoring, or when surveying a large number of sites.  To maximize swamp rabbit 131 detection, managers should place ALLs in areas of cover, especially near evidence of rabbit 132 activity, and leave them in place for several months to allow time for rabbits to establish latrines.   133 Acknowledgments 134 Our research was funded through the Federal Aid in Wildlife Restoration Program, project 135 W-106-R, administered by the Illinois Department of Natural Resources.  We acknowledge J. 136 Cole for his assistance with the project.  We also wish to thank The Nature Conservancy and 137 myriad land owners for granting permission to conduct this study on their properties.  B. 138   7 Eubanks, L. Berkman, A. Grunwald, R. Scharine, and many other volunteers from the Southern 139 Illinois University Carbondale student chapter of The Wildlife Society assisted in field work. 140  141 LITERATURE CITED 142 Animal Care and Use Committee. 1998. Guidelines for the capture, handling, and care of 143 mammals as approved by the American Society of Mammalogists. Journal of 144 Mammalogy 79:1416-1431. 145 Chapman, J. A. and G. A. Feldhamer. 1981. Sylvilagus aquaticus. Mammalian Species 151:1-4. 146 Foresman, K. R., and D. E. Pearson.  1998.  Comparison of proposed survey procedures for 147 detection of forest carnivores.  Journal of Wildlife Management 62:1217-1226. 148 Heuer, E. T., Jr. and H. R. Perry, Jr. 1976. Squirrel and rabbit abundances in the Atchafalaya 149 Basin, Louisiana. Proceedings of the Annual Conference of Southeastern Association of 150 Fish and Wildlife Agencies 30:552-559. 151 Kjolhaug, M. S., A. Woolf, and W. D. Klimstra. 1987. Current status and distribution of swamp 152 rabbits in Illinois. Transactions of the Illinois State Academy of Science 80:299-308. 153 Korte, P. A. and L. H. Fredrickson. 1977. Swamp rabbit distribution in Missouri. Transactions of 154 the Missouri Academy of Science 10:72-77. 155 McCollum, R. C. and N. R. Holler. 1994. Comparative use of floodplains by swamp rabbits. 156 Journal of the Alabama Academy of Science 10-11:72-77. 157 Scheibe, J. S. and R. Henson. 2003. The distribution of swamp rabbits in Southeast Missouri. 158 Southeastern Naturalist 2:327-334. 159 Terrel, T. L. 1972. The swamp rabbit (Sylvilagus aquaticus) in Indiana. American Midland 160 Naturalist 87:283-295. 161   8 Watland, A. M., E. M. Schauber, and A. Woolf. 2007. Translocation of swamp rabbits in 162 southern Illinois. Southeastern Naturalist 6:259-270. 163 Whitaker, J. O., Jr. and B. Abrell. 1986. The swamp rabbit, Sylvilagus aquaticus, in Indiana. 164 Proceedings of the Indiana Academy of Science 95:563-570. 165 Woolf, A. and M. S. Barbour. 2002. Population dynamics and status of the swamp rabbit in 166 Illinois.  Final Report.  Illinois Federal Aid Project W-106-R-12.  Southern Illinois 167 University, Carbondale, Illinois, USA. 168 Zollner, P. A., W. P. Smith, and L. A. Brennan. 1996. Characteristics and adaptive significance 169 of latrines of swamp rabbits (Sylvilagus aquaticus). Journal of Mammalogy 77:1049-170 1058. 171 Zollner, P. A., W. P. Smith, and L. A. Brennan. 2000. Microhabitat characteristics of sites used 172 by swamp rabbits. Wildlife Society Bulletin 28:1003-1011. 173 Associate Editor: McCleery. 174 175   9 Figure captions 176 Fig. 1.  Artificial latrine log (ALL).  (A) Swamp rabbits readily established fecal latrines on 177 many ALLs deployed in the early-successional habitat in southern Illinois, 2006-07.  (B) 178 Schematic of the ALL frame (without carpet top) showing collapsed and deployed 179 configurations.  For simplicity, the frame is not shown skeletonized.  180  181 Fig. 2.  Effectiveness of artificial latrine logs (ALLs) deployed in early successional sites in 182 southern Illinois, 2007.  (A) Increasing percent use of ALLs over time (in 2007) since 183 deployment.  Each line represents data from one site where swamp rabbits used ALLs.  (B) 184 Number of visits until initial detection for ALLs and live trapping on the basis of visits to each of 185 11 sites with known swamp rabbits.  For live trapping, visits reflect consecutive daily visits.  186 Horizontal line indicates the maximum number of ALL checks for a site. 187 188   10  189 190   11  191 

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An Artificial Latrine Log for Swamp Rabbit Studies

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