University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Erforschung biologischer Ressourcen der Mongolei Institut für Biologie der Martin-Luther-Universität / Exploration into the Biological Resources of Halle-Wittenberg Mongolia, ISSN 0440-1298

2010 Comparative Morphology of Two Sympatric Species of in Ikh Nart Nature Reserve, Mongolia Richard P. Reading Denver Zoological Foundation, [email protected]

David Kenny Denver Zoological Foundation

Sodnomphil Batdorj Denver Zoological Foundation

James Murdoch University of Vermont, [email protected]

Follow this and additional works at: http://digitalcommons.unl.edu/biolmongol Part of the Asian Studies Commons, Biodiversity Commons, Environmental Sciences Commons, Nature and Society Relations Commons, Other Sciences Commons, and the Zoology Commons

Reading, Richard P.; Kenny, David; Batdorj, Sodnomphil; and Murdoch, James, "Comparative Morphology of Two Sympatric Species of Hedgehog in Ikh Nart Nature Reserve, Mongolia" (2010). Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298. 64. http://digitalcommons.unl.edu/biolmongol/64

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Erforsch. biol. Ress. Mongolei (Halle/Saale) 2010 (11): 323-328

Comparative Morphology of Two Sympatric Species of Hedgehog in Ikh Nart Nature Reserve, Mongolia

R. P. Reading, D. Kenny, S. Batdorj & J. Murdoch

Abstract

Daurian hedgehog ( dauuricus) and long-eared hedgehog ( auritus) inhabit Ikh Nart Nature Reserve, Mongolia and both species appear to occupy similar niches. We gathered morphological measurements to test for differences between species and sexes. We hoped to gain insight into the mechanisms that allow the species to coexist. We collected morphometric data from 10 long-eared (6 WW, 4 and 18 Daurian hedgehogs (10 WW, 7 VV, 1 unknown sex). Only total body length in Daurian hedgehogs differed significantly be- tween males and females. Otherwise, we found no significant differences between morphomet- ric measures of male and female hedgehogs of either species. Daurian hedgehogs were larger than long-eared hedgehogs for every measurement except for ear length; however, only girth, weight, and length of ear differed significantly. A general linear model found that animal girth best differentiated the two species. Coexistence of species that occupy similar niches generally occurs through the differential use of resources and may be inferred from morphological differ- entiation. We plan continued research to better explore resource partitioning between the two species.

Key words: hedgehog, Hemiechinus, Mesechinus, Mongolia, morphology, steppe.

1. Introduction

Two species of hedgehog - the (Mesechinus dauuricus) and long-eared hedgehog (Hemiechinus auritus) - inhabit Ikh Nart Nature Reserve in northern Dornogobi Ai- mag, Mongolia (fig. 1 and 2) (MURDOCH et al. 2006a). Previous hedgehog accounts suggested that only the long-eared hedgehog inhabited this area of Mongolia (DULAMTSEREN 1970, CORBET 1988, REEVE 1994), but recent surveys indicated the presence of Daurian hedgehog in most major habitats of the reserve (MURDOCH et al. 2006b). Both species appear to occupy similar ecological niches and as such probably compete for food and habitat resources (READ- ING et al. 2007). Competition may be reduced through the differential use of resources (e.g., food, space, and time) and inferred from morphological differences between species (BEGON et al. 2006). Although both hedgehogs appear morphologically similar, few studies have examined their morphologies, especially in the context of competition and coexistence (REEVE 1994). We undertook this study to gather morphological measurements from both hedgehog species and to test for differences to gain insight into the mechanisms that allow them to coexist in Mongolia.

2. Study Area Ikh Nart Nature Reserve (Ikh Nart) was established in 1996 to protect 666 km2 of rocky outcrops in northwestern Dornogobi Aimag (MYAGMARSUREN 2000, MURDOCH et al. 2006a, READ- ING et al. 2006a). The region is a high upland (~1,200 m elevation) covered by semi-arid steppe vegetation. Permanent cold-water springs flow through some of the several, shallow valleys draining the reserve. Rocky outcrops cover a portion of the reserve, while open desert steppe dominates other portions. Climate is strongly continental and arid, characterized by cold winters (to - 40 °C), dry, windy springs (to 25 mps), and relatively wet, hot summers (to 43 °C). Precipitation is low and seasonal, primarily falling in the summer (June, July, and August) (READING et al. 2006a). Flora and fauna are representative of the semi-arid regions of Central Asia, with a mix 323 of desert and steppe species (MURDOCH et al. 2006a, READING et al. 2006a). Vegetation is sparse and consists mainly of xerophytic and hyperxerophytic semi-shrubs, shrubs, scrub vege- tation, and turfy grasses.

Fig. 1: Daurian hedgehogs (Mesechinus dauuricus), photos © Richard P.

Reading.

2. Methods

We quantified morphology by capturing and measuring hedgehogs in the study area. We cap- tured hedgehogs in four ways. First, we captured them opportunistically when we encountered them in their daytime resting sites (occasionally beneath rocky ledges, between boulders, or at the base of bushes or trees). Second, we captured them through night searches using handheld spotlights in vehicles at night. Third, and most commonly, we captured them inadvertently in padded leg-hold traps (Victor Softcatch 1 & 1.5, Woodstream Corporation, Lititz, Pennsylvannia, USA) set for small carnivores as part of another, on-going study in the reserve (MURDOCH 2009). We baited these traps with commercial hunting lures and modified them by increasing jaw offset to minimize the potential for injury. Fourth, we captured hedgehogs in box traps baited with meat, chicks (in separate cages), scents, or some mixture of these.

We attached ear tags (Conservation Tag # 1005-1, National Band and Tag, Newport, Kentucky, USA) and 3.6 or 6.0 g VHF radio transmitters (custom built, Advanced Telemetry Systems, Isanti, Minnesota, USA) on most as part of a parallel ecology study (READING et al. 2007). We weighed hedgehogs, and collected the following morphological measurements: total body length, girth at mid-body, length of foreleg, length of hind leg, length of forefoot, length of hind foot, ear length from inside ear, ear length from outside ear, tail length, girth of neck, and anogenital distance.

We tested for morphological differences in these measures between species. We also tested for differences between sexes within each species. We examined all variables for normality using

324 the Shapiro-Wilk’s test and homogeneity of group variance using Bartlett’s test. We sine trans- formed two variables (total body length and length of hind foot) to obtain a normal distribution and excluded measurements of an immature long-eared hedgehog from analyses. We com- pared means using simple t-tests, with corrections for separate variances where appropriate. We used general linear models and step-wise logistic regressions of body measurements to examine variables that best differentiate the two species.

Fig. 2: Long-eared hedgehogs (Hemiechinus auritus), photos © Richard P. Reading.

3. Results

We collected morphometric data from 24 hedgehogs, including 10 long-eared hedgehogs (6 WW, 4 VV) and 18 Daurian hedgehogs (10 WW, 7 VV, 1 unknown sex). Only total body length in Daurian hedgehogs differed significantly between males and females (t = 2.29, df = 15, P = 0.04). Otherwise, we found no significant differences (P > 0.05) between morphometric meas- ures of male and female long-eared hedgehogs (P > 0.12) or male and female Daurian hedge- hogs (P > 0.13; Table 1).

We found significant differences between some morphometric measurements of Daurian and Long-eared hedgehogs (Fig. 3, Table 1). Daurian hedgehogs were larger than long-eared hedgehogs for every measurement except for ear length (Fig. 1). However, only girth, weight, and length of ear measured from inside the ear differed significantly between long-eared and Daurian hedgehogs (Fig. 3, Table 1). We did not collect enough data on neck girth or length of foreleg to permit statistical tests. Using a general linear model to control for covariance in vari- ables, we found that animal girth best differentiated the two species (Table 2). A logistic model incorporated only animal girth (F = 138.15, df = 1, 25, R2 = 0.84, P = 0.001), but the effect was small (Coefficient = -0.009 0.001 SE).

325 Table 1: Mean (SE) morphometric measurements of Daurian (Mesechinus dauuricus) and Long-eared (Hemiechinus auritus) hedgehogs in Ikh Nart Nature Reserve, Mongolia. All measurements in mm, except for body mass, which is in grams

species ear ear total body tail girth hind foot body mass sex (inside) (outside) length Daurian W 24.20 20.11 26.33 340.30 267.30 41.33 1061.50 (n = 10) (± 1.61) (± 1.65) (± 1.95) (± 8.58) (± 8.45) (± 2.55) (± 60.71) V 24.86 21.17 31.00 335.86 255.57 40.50 1003.86 (n = 7) (± 2.31) (± 2.30) (± 2.16) (± 2.73) (± 9.96) (± 1.61) (± 36.28) all 24.78 20.53 28.38 339.94 261.78 41.00 1048.44 (n = 18) (± 1.26) (± 1.31) (± 1.52) (± 5.01) (± 6.08) (± 1.61) (± 37.73) Long-eared W 31.00 24.0 21.50 240.60 181.40 34.00 376.50 (n = 6) (± 1.76) (± 3.16) (± 4.63) (± 3.79) (± 7.24) (± 1.29) (± 6.96) V 31.25 26.00 16.90 237.00 173.25 30.67 312.50 (n = 4) (±1.32) (± 2.65) (± 5.88) (± 20.34) (± 12.60) (± 4.33) (± 52.06) all 31.50 24.86 19.20 235.60 178.00 32.57 337.50 (n = 10) (± 1.04) (± 2.01) (± 3.57) (± 8.38) (± 5.87) (± 1.90) (± 24.03) t-test: Daurian vs. Long-eard hedgehogs (all animals) t 4.14 1.69 2.07 12.31 0.14 0.53 19.73 P < 0.001 0.11 0.08 < 0.001 0.89 0.61 < 0.001 df 23.51 19.00 9.85 18.22 25.00 9.31 22.62

75 1200 70 65 H. auritus 1000 60 M . dauuricus 55 800 50 45

40 600 35

30 Weight (g) 25 400 20 15 200 Size in mm (or cm if indicated) cm (or mm in Size 10 5 0 0 Ear (inside) Ear (outside) Tail Girth (cm) TBL (cm) Hind Foot Foreleg Hindleg Neck H. auritus M. dauuricus Morphometric Variable

Figure 3: Comparison of mean (SE) morphometric measurements (left) and weights (right) of Daurian (Mesechinus dauuricus) and long-eared (Hemiechinus auritus) hedgehogs in Ikh Nart Nature Reserve, Mongolia. All measurements in mm, except for weight, which is in grams. TBL = total body length.

326 Table 2: Results of a general linear model using morphometric measurements to differentiate between Daurian (Mesechinus dauuricus) and long-eared (Hemiechinus auritus) hedgehogs in Ikh Nart Nature Reserve, Mongolia; Overall model: F = 13.82, df = 8, 12, R2 = 0.84, P < 0.001

Standard Standard Effect Coefficient Tolerance t P-Value Error Coefficient Constant 3.233 0.743 0.000 4.353 0.001 girth -0.007 0.003 -0.621 0.082 -1.970 0.072 tail -0.007 0.008 -0.100 0.643 -0.885 0.394 body mass -0.001 0.001 -0.384 0.055 -0.995 0.340 ear (onside) -0.013 0.017 -0.169 0.165 -0.760 0.462 ear (outside) 0.006 0.016 0.071 0.229 0.378 0.712 Gender -0.018 0.096 -0.020 0.762 -0.192 0.851 Sine (hindfoot) -0.014 0.077 -0.018 0.838 -0.185 0.856 Sine (TBL1) -0.004 0.070 -0.005 0.785 -0.051 0.961

1 Total body length

4. Discussion

Coexistence of species that occupy similar niches generally occurs through the differential use of resources, such as food, space, and time (SCHOENER 1974). Such resource partitioning reduces competition and may be inferred from morphological differentiation (BEGON et al. 2006). Daurian and long-eared hedgehogs occur sympatrically in Ikh Nart Nature Reserve and other arid steppe regions of Mongolia (CLARK et al. 2006) and occupy similar ecological niches (MURDOCH et al. 2006a). Our preliminary data suggest that they consume similar food resources, use similar habi- tats, and are active at similar times. Although we found overlap in body sizes, our results found some morphological differentiation between species, probably reflecting slightly different use of resources. Daurian hedgehogs were larger and heavier than long-eared, perhaps allowing them to better exploit some habitats. We found no sexual dimorphism among male and female hedgehogs of either species, suggesting that the different sexes do not partition resources.

We also began a radio telemetry study, but have only obtained sufficient data on Daurian hedgehogs to date (MURDOCH et al. 2006b). Although researchers have studied long-eared hedgehogs (e.g., SCHOENFELD & YOM-TOV 1985), little is known about Daurian hedgehogs (REEVE 1994) and we believe ours is the first in depth study of the species. We plan continued research to better explore resource partitioning between the two species.

Acknowledgments Several people helped make this work possible including Batorshikh, S. Buyana, Dandar, Dr. A. DeNicola, Enkhtaivan, Enkhtuvshin, Munkhdalai, Ts. Munkhzul, Olziiduuren, Onolragchaa, Ot- gonbayar, Selenge, E. Togoldor, Tsogterdene, Tsolmonbayar, Ulziibat, and all of our Earth- watch volunteers. Funding was provided by the Denver Zoological Foundation, Earthwatch Insti- tute, the Trust for Mutual Understanding, and the Mongolian Academy of Sciences.

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Addresses:

Richard P. Reading* Sodnomphil Batdorj David Kenny Mongolian Conservation Coalition Conservation Biology Department & Denver Zoological Foundation Denver Zoological Foundation Mongolia Program 2300 Steele Street Ulaanbaatar Denver Mongolia Colorado 80205 USA James Murdoch [email protected]* Rubenstein School of Environment and Natural Resources University of Vermont George D. Aiken Center * Corresponding author Burlington Vermont 05405 USA

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