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Wednesday, 7 December 2016
Seasonal and altitudinal variation in roe deer (Capreolus pygargus tianschanicus) diet on Jeju Island, South Korea
Published Date 1 December 2016, Vol.9(4):422–428, doi:10.1016/j.japb.2016.09.001 Open Access, Creative Commons license, Funding information Original article Author
aFaculty of Science Education, Jeju National University, Jeju, South Korea
bEducational Science Research Institute, Jeju National University, Jeju, South Korea
Received 29 June 2016. Revised 23 August 2016. Accepted 1 September 2016. Available online 9 September 2016.
Abstract
In order to understand the feeding ecology and dietary differences of roe deer (Capreolus pygargus tianschanicus) in different seasons and altitudes, this study was carried out at three altitudinal sites (Songdang 250–270 m above sea level (ASL), Aradong 330–370 m ASL, Mt. Hallasan 1100 m ASL) on Jeju Island, South Korea. Altogether, 205 plants taxa of six categories of foods (forbs-climbers, graminoids, trees, shrubs, conifers, and ferns) were identified using morphological and molecular analyses. The highest number of dietary plants was found in summer (93 taxa) and at Aradong (124 taxa) and lowest at Songdang (71 taxa) and in winter (51 taxa). Food categories were significantly different among the seasons (F = 15.646, p < 0.05) and altitudinal sites (F = 3.941, p < 0.05). This study revealed that dietary selectivity of roe deer shifted with seasonal and altitudinal variations and preferred to the nutritive and low fibers food.
Keywords
altitude
dietary plant
food categories
Jeju Island
roe deer
Introduction
The roe deer (Capreolus sp.) is a medium sized ungulate, globally divided into two species, Capreolus pygargus and Capreolus capreolus. In West Asia, Central Asia, and Northeast Asia, including South Korea, two subspecies of C. pygargus(Capreolus pygargus tianschanicus and Capreolus pygargus pygargus) are in existence (Danilkin 1996). In Jeju Island C. p. tianschanicus is distributed from coastal areas up to the high altitude region of Mt. Hallasan (Kim, 2000, Kim et al., 2007, Oh et al., 2015 and Yoon, 2003). It is a significantly impacting herbivore in the grassland and forest ecosystems, mostly affecting the composition of plant communities, plant productivity, and shaping the structure of vegetation (Danilkin 1996).
The study of the feeding ecology of animals is important in order to identify potential food resources (Minder 2012), predict their carrying capacities, and plan to minimize the damage in forest and agriculture (Cornelis et al., 1999 and Jackson, 1974). It helps to understand the quality of the food that significantly impacts on the growth, reproduction, and existence of animals, resulting in their population dynamics (Pekins et al 1998). Therefore, regular studies on the diet and dietary habit of herbivores are required before beginning habitat management and other conservation strategies. The dietary selection of herbivores mostly alters with the available plant resources. Seasonal and altitudinal variations are two fundamental factors for determining vegetation diversity (Oommen and Shanker 2005), which regulates the dietary habit of C. p. tianschanicus, as in other herbivores (Barancekova et al 2010).
Previous studies on the dietary species of C. p. tianschanicus present on Jeju Island were based on the observation of particular sites and feeding test experiments (Jeong et al., 2001, Kim, 2000, Oh et al., 2015 and Yoon, 2003) but did not provide sufficient information to explain the relationship between the feeding ecology and environmental differences. This study was carried out to understand the feeding ecology of C. p. tianschanicus, as well as correlations between dietary plant species and variations in environmental conditions on Jeju Island, South Korea.
Materials and methods
Study area
Jeju Island (33° 06ʹ–34° 00ʹ N and 126° 08ʹ–126° 58ʹ E) is the largest island (1848 km2) of South Korea. This study was carried out at three different altitudinal sites [Songdang, 250–270 m above sea level (ASL); Aradong, 330–370 m ASL; Hallasan 1100 m ASL] of Jeju Island (Figure 1) from July 2014 to April 2016.
Figure 1. Map of study sites. A, Songdang, 250–270 m ASL; B, Aradong, 330–370 m ASL; C, Hallasan 1100 m ASL. ASL = above sea level.
Direct observation
Field investigation was carried out every month at all study sites. The browsing pattern of C. p. tianschanicus was checked at every field visit. The plant specimens nibbled by C. p. tianschanicus were collected after morphological identification and field-recording. Each collected specimen was identified again according to Lee (2003). All collected specimens were preserved and deposited in the laboratory (JEL100-344). The conservation status of all identified species was checked in the Korean Red List of Threatened Species (NIBR 2012).
DNA sequence analysis
A molecular identification technique was applied for those plant specimens which were too damaged by C. p. tianschanicus and were difficult to identify by their morphological features. Total DNA was extracted from 0.4 mg of fresh sample using Wizard Genomic DNA Purification Kit (Promega, Wisconsin, USA). Universal primers designated by Taberlet et al., 1991 and Taberlet et al., 2007 were used in polymerase chain reaction (PCR) for the amplification of three chloroplast DNA regions (trnLintron, P6-loop of trnL intron, and trnL-trnF intergenic spacer). The PCR amplification mixtures contained: total volume 25 μl including 10× PCR buffer, 10 mM of dNTP, 10 pmol of each primer, 1.5 units Taq DNA polymerase (GenetBio, Daejeon, South Korea), and 1 μl genomic DNA. The PCR reaction was done using the Gene Pro Thermal Cycler (Hangzhou Bioer Technology, Hangzhou, China). The PCR mixture underwent 40 cycles with denaturation at 95ºC for 1 minute, annealing at 55ºC for 1 minute, and final extension at 72ºC for 1 minute. PCR products were separated using 1.5% agarose gel electrophoresis. The purified and amplified PCR product was sequenced using a dye-termination method with the help of the DNA sequencing professional company Macrogen Inc. (Seoul, South Korea). A similarity search for DNA sequences obtained in this study was conducted using the Basic Local Alignment Search Tool of the National Center for Biotechnology Information nucleotide database. The putative species were determined based on the similarity search results. Identification from the morphological study was cross-checked with the data obtained from molecular analysis.
Analysis of data
In order to compare the dietary selection of C. p. tianschanicus with respect to different seasons and altitudes, we classified plant species into six categories of food (forbs-climbers, graminoids, shrubs, trees, ferns, and conifers) based on plant morphology, growth forms, and life span (Barancekova et al., 2010, Cornelis et al., 1999 and Minder, 2012). The Shannon–Wiener diversity index (Shannon and Weaver 1949) was used to calculate the diversity of six categories of foods in each study site and season:
H′ = − ∑ (pi × ln (pi))
where, pi is the proportion of the number of species in the ith food category. One way analysis of covariance in IBM SPSS 24.0 (IBM Corp. Armonk, NY, USA) was used to assess the significant differences among seasons and altitudes.
Results
Dietary plant identification
A total of 205 plant taxa were collected (Table S1), identified, and classified into 34 orders, 56 families, 135 genera, and 165 species (Table 1). A total of 144 plant taxa were identified using morphological analysis, but 61 plant taxa could not be identified through morphological analysis and anatomical comparison, so we used the molecular technique for identification. However, not all plant taxa could be identified up to the species level using DNA sequence comparison. Twenty-two plant taxa were identified only to species level, but the remaining taxa were identified to the genus (11 taxa) and family (28 taxa) level. Altogether, 76 DNA sequences determined and identified dietary plants to different taxonomic levels (Table 2).
Table 1. Taxonomic status of dietary plants found in different study sites.
Indicates the plant taxa were not identified to species level.
Table 2. Species identification at different taxonomic levels using molecular technique.
Molecular marker
No. of DNA sequences
Species
Genus
Family
trnL intron
35
14
10
11
P6-loop of trnL intron
32
9
6
17
trnL-trnF intergenic spacer
9
2
5
2
Total
76
25
21
30
Dicotyledonae (144 taxa) were found in the highest proportion followed by Monocotyledonae (57 taxa), Coniferopsida (2 taxa), Lycopsida (1 taxon), and Leptosporangiate (1 taxon) (Table 3). Forbs-climbers contributed the highest proportion of the overall diet (56.58%) followed by graminoids (21.95%), trees (11.21%), shrubs (8.29%), conifers (0.97%), and ferns (0.97%). The highest numbers of plant taxa were observed in the Gramineae family (36 taxa).
Table 3. List of higher taxonomic levels of dietary plant species of Capreolus pygargus tianschanicus.
Class
Order
Family
No. of taxa
Leptosporangiatae
Filicales
Aspidiaceae
1
Lycopsida
Lycopodiales
Lycopodiaceae
1
Coniferopsida
Coniferales
Pinaceae
2
Monocotyledonae
Asparagales
Aspargaceae
1
Commelinales
Commelinaceae
1
Cyperales
Cyperaceae
8
Graminales
Gramineae
36
Liliales
Dioscoreaceae
3
Iridaceae
1
Liliaceae
5
Orchidales
Orchidaceae
1
Zingiberales
Zingiberaceae
1
Dicotyledonae
Apiales
Pittosporaceae
1
Campanulales
Campanulaceae
3
Compositae
17
Caryophyllales
Amaranthaceae
2
Caryophyllaceae
3
Chenopodiaceae
1
Cucurbitales
Cucurbitaceae
3
Ericales
Ericaceae
1
Fagales
Fagaceae
2
Gentianales
Apocynaceae
1
Oleaceae
4
Geraniales
Geraniaceae
1
Oxalidaceae
1
Simaroubaceae
1
Magnoliales
Lauraceae
2
Malphighiales
Violaceae
2
Myrtiflorae
Halorrahagaceae
1
Papaverales
Cruciferae
4
Parietales
Hypericaceae
1
Theaceae
1
Piperales
Saururaceae
1
Plantaginales
Plantaginaceae
1
Polygonales
Polygonaceae
6
Ranunculales
Berberidaceae
1
Menispermaceae
1
Ranunculaceae
10
Rhamnales
Vitaceae
4
Rosales
Leguminosae
23
Rosaceae
13
Rubiales
Adoxaceae
3
Caprifoliaceae
2
Rubiaceae
2
Sapindales
Aceraceae
3
Aquifoliaceae
1
Celastraceae
1
Tubiflorales
Acanthaceae
1
Convolvulaceae
1
Labiatae
7
Umbellales
Araliaceae
3
Cornaceae
1
Umbelliferae
3
Urticales
Cannabinaceae
1
Moraceae
1
Urticaceae
2
Seasonal variation in dietary selection
The summer season had the highest record of dietary plants (93 taxa), followed by spring (80 taxa), autumn (65 taxa), and winter (51 taxa). Forbs-climbers contributed a relatively higher proportion of the diet in spring (66.25%), summer (54.83%), and autumn (55.38%) (Figure 2). Graminoids contributed the second largest part of the diet and covered 22.5%, 25.8%, and 27.69% in summer, autumn, and spring, respectively, with the majority from the Gramineae, Cyperaceae, and Liliaceae families. In winter, the main diet of C. p. tianschanicus shifted towards woody trees (29.41%; Acer pseudosieboldianum, Quercus serrata, Viburnum dilatatum, and Pittosporum tobira) and perennial shrubs (27.45%). C. p. tianschanicus uses deciduous leaves, stems and barks of the trees, and evergreen climbers for its diet. Interestingly, conifers and ferns were also observed in the winter diet. Cereals, cultivated crops, and ornamental plants were also used for diet in late autumn, whole winter, and early spring.
Figure 2. Distribution of food categories in different seasons.
Diversity index H′ of dietary plant species was highest in winter (H′ = 1.559), followed by summer (H′ = 1.124), autumn (H′ = 1.086), and spring (H′ = 0.923). The dietary selection of food categories (forbs-climbers, graminoids, shrubs, trees, conifers, and ferns) were statistically significant among seasons (one way analysis of covariance, F= 15.646, p < 0.05). Comparison of means (one way analysis of covariance, Games-Howell test) between seasons showed that the highest mean difference was found between winter and spring [I − J = 1.849, standard error (SE) = 0.298], followed by winter and autumn (I − J = 1.427, SE = 0.338) and winter and summer seasons (I − J= 1.411, SE = 0.319) (Table 4).
Table 4. Multiple comparisons showing mean difference between seasons in dietary plants species.
Plants belonging to the forbs-climbers found a high degree of selection at all study sites (Songdang, 49.29%; Aradong, 62.9%; Hallasan, 45.88%). The highest number of plant taxa in the forbs-climbers category at all study sites were from the Leguminosae family. Graminoids were the second highest at all sites (Songdang, 29.57%; Aradong, 13.70%; Hallasan, 22.35%) (Figure 3). Gramineae was the most common family of the graminoids, and was dominant at all study sites. Shrubs under the families Rubiaceae, Rosaceae, and Berberidaceae were frequently used in the diet and their consumption was highest at Aradong. With an increase in altitude, the proportions of trees and conifers in the diet increased. Many cases of tearing and peeling the bark from trees were observed in the forests of Aradong and Hallasan. Twelve taxa of trees were partially damaged at Hallasan and seven taxa at Aradong by C. p. tianschanicus. Two species of ferns (Athyrium koryoense and Lycopodium chinense) were observed at Songdang and Aradong, and only one species (A. koryoense) at Hallasan. We have observed the damages in agriculture and horticulture plants by roe deer in Aradong. Ten species of cultivated plants, including radish, pumpkin, nappa cabbage, and deodeok (Codonopsis lanceolata) and three species of ornamental plants Rhododendron schlippenbachii, Camelia japonica, and Abelia grandiflora were browsed by C. p. tianschanicus. Six species of endemic plants of Jeju Island and two species of threatened taxa (Abies koreana and Cirsium rhinoceros) were detected in the diet (Table 5).
Figure 3. Distribution of food categories in different sites.
Table 5. List of endemic flora of Jeju Island found in the diet of Capreolus pygargus tianschanicus.
Family name
Scientific name
Common name
Finding site
Pinaceae
Abies koreana
Red-cone Korean fir
Aradong, Hallasan
Fagaceae
Quercus glauca
Ring-cup oak
Hallasan
Berberidaceae
Berberis amurensis var. quelpartensis
Jejudo berberry
Songdang, Hallasan
Labiatae
Scutellaria indica var. coccinea
Pink Indian skullcap
Aradong
Compositae
Cirsium rhinoceros
Korean prickly thistle
Aradong, Hallasan
Urticaceae
Boehmeria hirtella
Hairy long leaf false nettle
Aradong
Diversity index H′ of dietary species at Songdang, Aradong, and Hallasan was 1.261, 1.137, and 1.342, respectively. Food categories (forbs-climbers, graminoids, shrubs, trees, conifers, and ferns) were statistically significant among the three altitudinal sites in dietary selection (one way analysis of covariance, F = 3.941, p < 0.05). Comparison of means (one way analysis of covariance, Games-Howell test) between different sites showed that highest mean difference was found between Hallasan and Songdang (I − J = 0.651, SE = 0.260) and the lowest was between Hallasan and Aradong (I − J = 0.577, SE = 0.260) (Table 6).
Table 6. Multiple comparisons showing mean difference between sites in dietary plant species.
The dietary study of C. p. tianschanicus identified 205 potential taxa, which was broader in terms of species number than previous studies carried out on Jeju Island. Compared with previous studies on Jeju Island, 31.85% genera and 21.76% species matched those found by Oh et al (2015) and 17.03% genera and 8.16% species matched those found by Kim (2000). In contrast to Kim (2000) and Oh et al (2015), this study was carried out in relatively different habitats (forests and shrub lands of different altitudes, cultivated land and semi urban areas, and pasture land) in different seasons. Kim (2000) used the feeding test experiment on captured animals in an artificial environment and Oh et al (2015) focused their study in and around cultivated land; therefore neither of these studies could represent the actual feeding behavior in free-range conditions in the wild. Dietary species were found to be markedly different in number and species in C. p. pygargus abundant in Russia (Argunov and Stepanova 2011) and C. capreolus abundant in West Asia and Europe (Czernik et al., 2013, Mysterud et al., 1997 and Wallach et al., 2010). Changes in altitude and latitude cause climatic variation which affects the richness, evenness, and diversity of plants species (Willig et al 2003). Other environmental factors, such as topography and soil quality, could also be possible reasons for the large difference in plants species.
Our study revealed that roe deer is an intermediate feeder (Hofmann 1989) has found to be consumed six categories of plants (forbs-climbers, graminoids, shrubs, trees, conifers, and ferns) but when the resource was plentiful their concentration was found in forbs, climbers, and bamble based food (e.g., Rubus sp.). Bidens frondosa, Paederia scandens, Vicia villosa, Mimosa pudica, Vigna sinensis, Hedera rhombea, Aster hayatae, C. rhinoceros, and Cassia nomame are some representative species of which dietary selectivity was high. The lower values of diversity indices in spring and summer seasons support these findings. The general approach of diet selection could be to maximize the nutrient (protein and sugar) intake, minimize toxic compounds, and facilitate the intake of less-fibrous and easily digestible food (Hanley, 1997 and Hofmann, 1989). Dietary preferences for these food categories were reported in previous studies of Jeju Island (Kim, 2000, Oh et al., 2015 and Yoon, 2003) and for C. pygargus in Russia (Argunov and Stepanova 2011) and C. capreolus in Europe (Barancekova et al., 2010 and Minder, 2012). In autumn, the abundance of herbaceous plants was reduced and the dietary selection shifted towards the vegetative part of deciduous trees and half woody brows, particularly thorny shrubs together with forbs and graminoids, as reported in the diet of C. capreolus by Minder (2012). The highest value of the diversity index in winter and the highest significant difference between spring and winter seasons revealed that C. p. tianschanicus consumed a broad category of food in the winter. Due to cold and low moisture in winter, aerial parts of herbaceous and graminoid plants usually die and their seeds might be in dormant stage instead of germinating and growing, which resulted in less abundance of dietary species. Thus, dependency on forbs-climbers and graminoids reduced significantly and dietary requirements were covered by other categories of foods such as trees, shrubs, conifers, and ferns, including cultivated crops as reported in the dietary studies of C. pygargus in Russia (Argunov and Stepanova 2011) and C. capreolus in Europe (Barancekova et al., 2010, Goetsh and Wigg, 2011, Minder, 2012 and Mysterud et al., 1997).
Altitude is an important factor for determining species richness and diversity of plants (Oommen and Shanker 2005). The increase in elevation and the decrease of temperature leads to a reduction in biodiversity (Trigas et al 2013). Lower altitudes have a higher temperature compared with high altitudes, which results in high biodiversity and a more enhanced opportunity for dietary selection. The Songdang site is pastural land of Jeju Island, located at the lowest altitude. Usually, there might be high biodiversity, but grassland management activities and a preference to grow graminoid species has led to the reduction of other categories of plants. A total of 10 species of graminoids, including Agrostis clavata, Imperata cylindrica, Miscanthus sinensis, and Poa annua, were found more frequently in the diet. The intermediate value of the diversity index at Songdang revealed that C. p. tianschanicus was relatively less selective and certain categories of food might be consumed in higher proportions. The lowest value of the diversity index at Aradong revealed that C. p. tianschanicus was relatively more selective in dietary species. It was selected the forbs-climbers belonging to the Compositae, Leguminosae, Rosaceae, and Ranunculaceae families over other food categories. With an increase in the altitude, consumption of graminoids, trees, and conifers was increased. At Hallasan there was much snowfall and chilly weather in winter compared with the other sites (Songdang and Aradong) and as a result only low numbers of herbaceous plants were available, so the major dietary dependency shifted towards the higher and evergreen plants. We found the highest proportion of trees and conifers in the winter diet at higher altitudes, which is in accordance with the study by Mysterud et al (1997) on C. capreolus in Norway.
Based on direct observation and browsing signs at the study sites, we predicted that some plants such as Adenophora remotiflora, Plantago asiatica, C. rhinoceros, Disporum sessile, Chenopodium album, Hosta minor, A. hayatae, Potentilla fragarioides var. major, Clematis mandshurica, Agrostis flaccidi var. trinii, Arundinaria simonii, Cynodon dactylon, Berberis amurensis var. quelpartensis, Rubus parvifolius, and Morus bombycis, of the food categories forbs-climbers, graminoids, shrubs, and trees, could be the major dietary species of C. p. tianschanicus. Most of these species were also documented as the favorable dietary species of C. p. tianschanicus (Kim 2000). Jeju Island is rich in endemic vascular taxa (90 sp.) (Kim 2009). Geographical isolation and limited interchange of biota with the inland could be the reason for this high degree of endemism. We found six endemic taxa in the diet, which were also described in previous dietary reports of Jeju Island (Kim, 2000, Oh et al., 2015 and Yoon, 2003).
Dietary resources were found to be sufficient for C. p. tianschanicus in spring, summer, and autumn, but not in winter. Due to the lack of food in the natural habitat, the C. p. tianschanicus population was concentrated in and around cultivated land, damaging the food crops. We have listed 13 species of cultivated and ornamental plants browsed by C. p. tianschanicus. Similar reports were found in previous studies carried out on Jeju Island (Jeong et al., 2001, Oh et al., 2015 and Yoon, 2003). The crop loss was much more frequent in midaltitude mountainous areas, especially during heavy snowfall.
Trees in the forests of Aradong and Hallasan were damaged by C. p. tianschanicusthrough browsing of the lateral branches and peeling off the bark of the trees using their antlers (data not shown). Kim et al (2012) found 25 species of trees were seriously damaged in the southeastern marginal region of the Hallasan National Park. In addition, overgrazing and browsing activities of C. p. tianschanicus during the germinating and growing season can dramatically decline the plants communities as well as increase the number of threatened species (Goetsh and Wigg 2011). In accordance with Yoon (2003), we also found threatened plant taxa (A. koreana and C. rhinoceros) in the diet, which indicated that the regular diet of C. p. tianschanicusconsists of some threatened plant taxa. Further study is required to understand the impact of C. p. tianschanicus on the threat to plant species. Crop loss and forest damage caused by C. capreolus in Europe has also been reported (Holisova et al., 1982, Kjostvedt et al., 1998 and Putman, 2012).
The dietary preference of C. p. tianschanicus found in this study, in decreasing order, was forbs-climbers, graminoids, shrubs, trees, conifers, and ferns. The dietary species in spring and summer were highly selective, with predominantly herbaceous vegetation which is rich in nutrient content as well as being easily digestible but in winter all categories of plant and food groups were used in the diet. Our findings showed that the dietary species and habit of C. p. tianschanicus shifted with environmental conditions, such as seasonal and altitudinal variations. This study suggests that information on dietary species in different seasons and altitudes may help to understand the feeding ecology of C. p. tianschanicus, and local environmental conditions should be considered for natural habitat management and adoption of other conservation strategies.
Acknowledgments
The study was supported by a grant from the Jeju Green Environment Center under the Research Development Program (2014) and the authors are thankful for the assistance.
Appendix A Supplementary data
The following is the supplementary data related to this article:
The current number of its individuals and management plan of roe deer (Capreolus pygarus tianschanicus Satunin) inhabiting Mt. Halla (Hallasan), Jeju Island, Korea
Korean Journal of Environment Ecology, Volume 21, 2007, pp. 66–373
Understanding genetic diversity and population structure of a Poa pratensisworldwide collection through morphological, nuclear and chloroplast diversity analysis
Elevational gradient of vascular plant species richness and endemism in Crete-the effect of post-isolation mountain uplift on a continental island system
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