Population dynamics of japanese serow in relation to social organization and habitat conditions. I. Stability of Japanese serow density in stable habitat conditions

The density of a Japanese serow (Capricornis crispus) population, which has been in stable habitat conditions and free from hunting and predation, was investigated by direct observation of serows at Kusoudomari (336 ha), Wakinosawa village, Aomori Prefecture, Japan, during 1977–89. The vegetation, composed of mature mixed forest ofThujopsis with deciduous trees (43.2%), secondary forest of deciduous trees (23.4%) and a plantation of coniferous trees (30.0%) showed little change during the study period. The serows were counted 17 times each winter for 14 consecutive years. The serow population maintained a stable density with a mean of 12.5 individuals km⁻² (SD=1.4) ranging from 8.6 to 14.6 km⁻². The ratio of the proportion of kids (<1 year old) to serows more than 1 year old decreased, but density did not decrease during the study period. Though extremely severe winters with heavy snowfall in 1984–86 caused a decline in serow density, the density recovered within a few years. It was considered that the stability of the serow density resulted mainly from the stable food supply and the lack of human disturbance, such as forest cutting in the habitat. Stable population density for a long period is probably related to the social organization of the serow.     

西藏慈巴沟自然保护区鬣羚生境选择的季节性变化

2001 年12 月至2002 年8 月, 在西藏察隅慈巴沟国家级自然保护区采用设立固定样方的方法, 调查鬣羚对植被类型, 海拔、坡度、郁闭度、隐蔽度以及水源距离等指标的选择利用情况。通过计算Ivlev 的选择性指数,对鬣羚植被类型选择及其季节性变化进行了研究。研究发现, 鬣羚冬季主要选择箭竹—针叶林型, 到春季向下迁移, 对针阔混交林的选择性最大, 而夏季向上迁移, 利用范围扩大, 选择类型包括针阔混交林、箭竹—针叶林、杜鹃—针叶林。鬣羚对植被与对海拔高度选择趋势呈极显著相关( P < 0.01) , 表明海拔高度和植被类型对鬣羚活动分布有着相似的影响。食物的季节性变化可能是鬣羚对植被类型和垂直高度选择变化的主要原因。鬣羚在春季和冬季对平缓坡利用最大, 夏季对急陡坡利用最大, 这可能是因为随坡位变化而表现出的冬春与夏季差异。但鬣羚对隐蔽度、郁闭度和水源距离这3 个因子的选择并没有表现出明显的季节变化, 仅表现为利用中隐蔽度、高郁闭度和距离水源较近的地方。     

A comparison of food habits of two sympatric ruminants of Mt. Yatsugatake,central Japan: sika deer and Japanese serow

Comparison of food habits of sympatric animals provides understanding of interspecific relations. Previous studies of food habits of the two ruminants of Japan, sika deer (Cervus nippon) and Japanese serows (Capricornis crispus), have shown that sika deer are variable, and they are gazers in northern Japan, but browsers in southern Japan, whereas Japanese serows are browsers. However, these studies described the food habits of each species separately, and no study has compared the food habits of these species living in sympatry. Therefore, we examined these species on Mt. Yatsugatake, central Japan, using microhistological analyses and nutritional analyses of feces. Sasa nipponica, a dwarf bamboo, predominated in the fecal composition of sika deer, whereas both S. nipponica and dicotyledonous plants were found in the feces of Japanese serows. Crude protein levels of serow feces were higher than those of deer. The particle sizes of plant fragments in serow feces were smaller than those in deer feces, suggesting that serow fed more selectively on digestible plants than deer did. These results support the suggestions of previous studies conducted in different habitats and show that sika deer are less selective grazers, and Japanese serows are more selective browsers. Thus, food differences are likely explained by the feeding ecophysiology of the animals and not habitat differences.     

Molecular phylogenetic status of the Korean goral and Japanese serow based on partial sequences of the mitochondrial cytochrome b gene

To investigate the molecular phylogenetic status of the Korean goral, Nemorhaedus caudatus raddeanus, and Japanese serow, Capricornis crispus, we determined partial sequences of the mitochondrial cytochrome b gene of twelve Korean gorals and sixteen Japanese serows, and compared them with those of the major lineages of Rupicaprini species including two other Nemorhaedus species and two other Capricornis species. The Korean gorals examined possessed two haplotypes with only one nucleotide difference between them, while the Japanese serows showed slightly higher sequence diversity with five haplotypes. Genetic distances and molecular phylogenetic trees indicated that there is considerable genetic divergence between the Korean goral and N. caudatus (the Chinese goral) [Groves and Shields (1996)], but virtually none between Korean and Russian gorals. The Korean and Russian gorals may therefore be distinct from the Chinese goral. The data highlight the importance of conservation of the goral populations of these regions, and the need to reconsider the taxonomic status of Korean and Russian gorals. Our study also clearly demonstrated sufficient genetic distance between serows and gorals to justify their assignment to separate genera. Of the three species of Capricornis, the Formosan serow, C. swinhoei is more closely related to C. sumatraensis than to the Japanese serow, suggesting that the Formosan serow is a distinct species. Preliminary data on intraspecific genetic variation in the Japanese serow are also presented.     

Landscape-scale evaluation of habitat uses by sympatric mammals foraging for bark and buds in a heavy snowfall area of northern Japan

This study focused on influences of three different growing populations of mammals foraging for bark and buds—Japanese serows (Capricornis crispus), Tohoku hares (Lepus brachyurus angustidens), and Japanese macaques (Macaca fuscata)—on a cool-temperate forest in northern Japan. To acquire the initial knowledge to facilitate ecological monitoring of the influences, we evaluated habitat uses by each species on a landscape scale by using ecological niche factor analysis (ENFA), and identified commonalities and differences among the uses by using discriminant analysis (DA). Within a 50-km² area, we selected five 5-km transects and recorded tracks of each mammal on the snow surface along transects during the month of March in 2008 and 2009. The track data were used as the proof of species presence for entry into ENFA and DA. Marginality and specialization of species habitat use, computed by ENFA, indicated that the macaque habitat represented the most heterogeneous distribution and the lowest environmental tolerance, which was strictly limited by altitude and terrain conditions to prevent exposure to severe cold climate conditions. This refuge selection by macaques resulted in habitat segregation from serows, although it appears that both mammals prefer the same young broadleaf forests. Meanwhile, the serow was observed to be distinctly inclined to use mountainous forests and to avoid artificial environments. As a result, its habitat could be differentiated from that of the hare, as confirmed by coefficients of a discriminant factor. These findings indicate that the impact of three different mammals foraging on the native vegetation could be quite restrictive.     

Establishment of vascular endothelial cell lines from the aortas of wild Japanese serows (Capricornis crispus)

Endothelial cell lines were established from the aortas of wild Japanese serows (Capricornis crispus) by transfection of a simian virus 40 (SV40) large T antigen gene. The cloned cell lines, designed SeET (Japanese serow endothelial-SV40T) cells, express SV40T antigen and retain cobblestone-like morphology. Although von Willbrand Factor (vWF) is expressed in the cells, the expression rate and the quantity are lower than in serow primary endothelial cells. The SeET cells exhibit positive uptake of acetylated low density lipoprotein and dose-dependent cell proliferation upon exposure to vascular endothelial growth factor. These results suggest that these SeET cells have preserved endothelial phenotypes and able to function with decreased expression of vWF. The SeET cell line will be a valuable tool for in vitro studies on the physiological properties of endothelial cells and for the propagation of viruses and parasites of Japanese serows.     

Habitat preferences of medium/large mammals in human disturbed forests in Central Japan

It is a great concern whether human disturbed forest, i.e., secondary forest or monoculture forest, can be a habitat for the wildlife. We examined habitat preference of medium/large terrestrial mammal species in a human-disturbed mountainous settlement area of Akiyama Region, Central Japan, by using camera-traps, which were placed at conifer plantation forest, high/low-disturbed deciduous broad-leaved forest, and broad-leaved/conifer mixed forest in 2008 and 2009. Camera-traps were operational for 4568.6 trap-nights producing 740 photo-captures of 13 medium/large terrestrial mammal species. Japanese serow and Japanese hare dominated 54 % of all photo-captures. Low-disturbed deciduous broad-leaved forest showed the richest mammal fauna (12 spp.). We suggested that fruit trees and understory vegetation provided suitable habitat for frugivorous as well as herbivorous mammals. The mixed forest showed the lowest mammal fauna (6 spp.), which located higher elevation. High-disturbed deciduous broad-leaved forest (9 spp.) was also supposed to be a better habitat for some frugivorous mammals and herbivorous mammals, but tended to be avoided by Japanese marten and Japanese macaque. Conifer plantation forest (7 spp.) with understory vegetation was supposed to be a better habitat for Japanese serow and Japanese hare, but not for the other species. Without fruit trees, conifer plantation forest was supposed to be non-attractive habitat for frugivorous mammals. We demonstrated that, if a forest had been disturbed by human, the forest can be a habitat for terrestrial herbivores, but this was not always true for frugivores.     

When to Run and When to Hide: The Influence of Concealment,Visibility, and Proximity to Refugia on Perceptions of Risk

An animal's ability to avoid predation likely depends on its ability to detect approaching predators, conceal itself, and seek refuge or protection from predators. Habitat, especially vegetation structure, can influence all of these factors concurrently. Binary categorical assessments of habitat as ‘open’ or ‘closed’, however, confound at least two functions of habitat structure that could influence the perceived risk of predation: concealment, which functions to hide an individual, and visibility, which enhances detection of a potential predator. Both can influence predation risk independently and s imultaneously. In this study, we decoupled these functional properties of vegetation and studied the effects of concealment, visibility, and proximity to a refuge on the distance at which pygmy rabbits (Brachylagus idahoensis) fled from an approaching threat (flight initiation distance; FID). Concealment by vegetation decreased perceptions of risk; however, pygmy rabbits exhibited elevated risk at high levels of visibility, regardless of the amount of concealment. Proximity to burrow entrances also influenced perceptions of risk, such that risk was significantly lower when rabbits were on or near burrow systems. Disentangling the functional properties of habitat can provide a more comprehensive understanding of the factors that influence perceived risk and escape behaviors of prey and provide insight into how habitat structure mechanistically relates to predation risk.     

Direct evidence for Toxoplasma gondii infection in a wild serow (Capricornis crispus) from mainland Japan

Toxoplasma gondii infection was studied in 41 Japanese serows ( Capricornis crispus ), a goat-antelope in mainland Japan. Blood and muscle specimens were collected from 41 subjects between 2006 and 2010. Presence of antibodies to T. gondii in the sera was examined by using the latex agglutination test (cutoff titer 1:32); 10 of 41 (24.4%) were seropositive. Toxoplasma gondii DNA was detected in muscle tissue of 1 seropositive serow using a semi-nested PCR assay for the B1 gene. A partial nucleotide sequence (220 bp) corresponding to the B1 gene of T. gondii was obtained by direct sequencing; the sequence was 99.1% identical to that of the RH strain. This study is the first report to show direct evidence for the T. gondii infection in Japanese serows.     

Relationship between some chemical components of herbage, dietary preference and fresh herbage intake rate by the Japanese serow

The serow is a native Japanese mammal and has been designated as a special natural treasure. However, it has been a pest of crops since the 1970s. Since the serow is an indigenous and protected species, it must be controlled without endangering the animal itself. To do this, it is necessary to determine if the serow selects particular crops to consume, and if so, what components of the crop plants influence this choice.In Experiment 1, we measured the preference of four serows for two crop plants and three wild plants, using the cafeteria method. The plants were offered to the animals from 09.00 to 15.30. The serows preferred crop plants to wild plants. The crude protein content of crop plants (28.0 and 32.7%) was higher than that of the other plants (P<0.05). Dry matter (DM) intakes per hour correlated positively with crude protein content (P<0.01) and negatively with nitrogen free extract content (NFE) (P<0.05) and acid detergent fibre content (ADF) (P<0.01) in the offered plants. In Experiment 2, the food intakes of 17 plants consisting of 6 crops and 11 wild plants were measured. Individual 300g samples from each plant were offered for 20min. The serows ate the crops and the forbs in preference to the tree leaves. They consumed little of the conifer tree leaves and the grasses. The dry matter intake and the ADF content were negatively correlated (P<0.05). The dry matter intake and the crude protein content were positively correlated (P=0.054). A multiple regression formula was constructed as follows: Y=1.65CP+0.56NFE+0.38DM-57.45,R(2)=0.54,P=0.016The feeding characteristics suggest that crops might be selected and ingested by the serows because of their higher crude protein, NFE and the dry matter contents.     

Distribution pattern of the threatened Himalayan serow (Capricornis thar) in western midhills of Nepal: An insight for conservation along an altitudinal gradient

Almost nothing is known about the distribution and status of the Himalayan serow, an IUCN category “near threatened” ungulate, formerly widely distributed from subtropical to subalpine regions, in the Nepalese Himalaya. Heavy hunting, together with habitat loss and fragmentation are believed to have caused local extinctions in many sites within its geographical range. Distribution pattern of this dense forest dwelling threatened ungulate thus indicates conservation status of the whole unique ecosystems of this region. The objective of this study was therefore to assess distribution and status of serow in the Nepalese midhills. We conducted surveys, based on sightings and indirect presence signs, in western Nepal, between the subtropical Bardia National Park in the south and mountainous Shey Phoksundo National Park in the north, during 2008–2010. We recorded serow in the Bardia National Park. Further to the north, we recorded it only in highly rugged and inaccessible areas in the high altitudes, which suggests their possible extinction in the midhill region. The serow presence was strongly positively correlated with hunting intensity and forest intactness index. The populations of serow, scattered in the region, are small and therefore likely to be sensitive to demographic stochasticity. This all may consequently lead to future extinction of serow in the entire region. This information can be used to aid further research and decision-making processes for conservation planning along altitudinal gradient of Nepal's Himalaya.     

Genetic variation and phylogenetic relationship between three serow species of the genus Capricornis based on the complete mitochondrial DNA control region sequences

The molecular evidence of phylogenetic status regarding the Formosan serow (Capricornis swinhoei) is not robust and little is known about the genetic diversity of the Sumatran serow (Capricornis sumatraensis), which partly is due to the hardness in sample collection. Here we determined the sequences of the complete mitochondrial DNA control region (1,014 bp) of 19 Sumatran-serow individuals. Nine new haplotypes were defined based on 78 variable sites. Combined analysis with other 32 haplotypes downloaded from the public database, including 1 Sumatran-serow, 11 Formosan-serow and 20 Japanese-serow (Capricornis crispus) haplotypes, a relatively high level of nucleotide diversity was first observed in Sumatran serow (π = 0.0249). By comparative analysis with structural consensus sequences from other mammals, we have identified central, left and right domains and depicted the putative functional structure, including extend termination associated sequences and conserve sequence blocks, in mtDNA control region. The alignment of mtDNA control region revealed that both Sumatran and Japanese serow have two tandem repeats (TRs), but three TRs in Formosan serow. Phylogenetic analyses revealed that the Formosan serow is distinct species with the Japanese serow, but a sister group with the Sumatran serow. The divergence time estimated among three serow species revealed that Pleistocene climate changes and the uplift of Qinghai-Tibetan plateau might play an important role in the genetic differentiation of the serows. These results mainly provide the convinced evidence on the genetic relationship between three serow species.     

Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird

In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius collurio) that recently expanded its breeding habitat into open areas in plantation forests. This passerine bird shows a strong preference for forest habitat, but it has a higher nest success in farmland. We tested whether higher abundance of nest predators in the preferred habitat or, alternatively, a decoupling of nest predator abundance and nest predation explained this observed pattern of maladaptive habitat selection. More than 90% of brood failures were attributed to nest predation. Nest predator abundance was more than 50% higher in farmland, but nest predation was 17% higher in forest. Differences between nest predation on actual shrike nests and on artificial nests suggested that parent shrikes may facilitate nest disclosure for predators in forest more than they do in farmland. The level of caution by parent shrikes when visiting their nest during a simulated nest predator intrusion was the same in the two habitats, but nest concealment was considerably lower in forest, which contributes to explaining the higher nest predation in this habitat. We conclude that a decoupling of nest predator abundance and nest predation may create ecological traps in human-modified environments.     

Unique spatial behavior of the Japanese serow (Capricornis crispus) in the open mountains of Mt. Fuji

acta ethologica - The Japanese serow (Capricornis crispus) exhibits spatial behavior adapted to forest habitats with relatively stable food supply and climatic conditions, such as sedentary habits,...     

Testing the importance of nest concealment: does timing matter?

ABSTRACT.   Nest concealment by vegetation is considered an important factor affecting predation rates for many passerines and, therefore, is frequently measured in studies examining nest predation. However, the time when concealment measurements are made may affect the results of such studies, particularly in highly seasonal ecosystems where characteristics of the vegetation later in the breeding period may differ considerably from those at the time of nest-site selection. We used artificial nests baited with quail ( Coturnix sp.) eggs in a highly seasonal tropical dry forest in Jalisco, western Mexico, to test the effects of seasonal change in concealment on nest predation. We placed 40 open-cup, artificial nests in shrubs at the end of the dry season and again at the beginning of the rainy season in 2007, and monitored the fate of the nests and the degree of concealment by vegetation during both periods. Nest concealment was significantly greater during the wet season than during the dry season. The percentage of nests predated was marginally higher during the dry (100%) than the wet (72.5%) season, and daily nest survival was lower during the dry than the wet season. Our results suggest that, in highly seasonal environments such as tropical dry forests, delayed measurement of nest concealment after nest completion rather than during nesting may constitute a significant source of error.     

Selection of food patches by sympatric herbivores in response to concealment and distance from a refuge

Small herbivores face risks of predation while foraging and are often forced to trade off food quality for safety. Life history, behaviour, and habitat of predator and prey can influence these trade‐offs. We compared how two sympatric rabbits (pygmy rabbit, Brachylagus idahoensis; mountain cottontail, Sylvilagus nuttallii) that differ in size, use of burrows, and habitat specialization in the sagebrush‐steppe of western North America respond to amount and orientation of concealment cover and proximity to burrow refuges when selecting food patches. We predicted that both rabbit species would prefer food patches that offered greater concealment and food patches that were closer to burrow refuges. However, because pygmy rabbits are small, obligate burrowers that are restricted to sagebrush habitats, we predicted that they would show stronger preferences for greater cover, orientation of concealment, and patches closer to burrow refuges. We offered two food patches to individuals of each species during three experiments that either varied in the amount of concealment cover, orientation of concealment cover, or distance from a burrow refuge. Both species preferred food patches that offered greater concealment, but pygmy rabbits generally preferred terrestrial and mountain cottontails preferred aerial concealment. Only pygmy rabbits preferred food patches closer to their burrow refuge. Different responses to concealment and proximity to burrow refuges by the two species likely reflect differences in perceived predation risks. Because terrestrial predators are able to dig for prey in burrows, animals like pygmy rabbits that rely on burrow refuges might select food patches based more on terrestrial concealment. In contrast, larger habitat generalists that do not rely on burrow refuges, like mountain cottontails, might trade off terrestrial concealment for visibility to detect approaching terrestrial predators. This study suggests that body size and evolutionary adaptations for using habitat, even in closely related species, might influence anti‐predator behaviors in prey species.     

高山森林林窗对凋落叶分解的影响

林窗对降水和光照等环境条件的再分配以及分解者群落的影响可能深刻作用于森林凋落物分解过程,但有关高山森林林窗大小对凋落物分解的影响尚无研究报道。采用凋落物分解袋法,研究了川西高山森林不同大小林窗对非生长季节和生长季节红桦(Betula albo-sinensis)和岷江冷杉(Abies faxoniana)凋落叶质量损失的影响。结果显示,经过1a的分解,不同生境下红桦和岷江冷杉凋落叶分别分解了27.25%—30.12%和27.04%—27.96%,其中非生长季节占53.83%—60.18%和50.23%—59.09%。林窗对红桦和岷江冷杉凋落叶质量损失的影响因物种不同而呈现季节差异。总体上,林窗加快了岷江冷杉凋落叶的分解而延缓了红桦凋落叶的分解。与郁闭林下相比,林窗显著增加了2种凋落叶非生长季节的质量损失速率,显著降低了生长季节2种凋落叶的质量损失速率;2种凋落叶质量损失速率在非生长季节随林窗面积增大而加快,在生长季节随林窗面积增大而减慢。林窗显著影响了初冻期、深冻期和融化期岷江冷杉凋落叶的质量损失率,但对红桦凋落叶质量损失率影响不显著。可见,高山森林凋落物分解过程受到林窗的显著影响,并且阔叶和针叶凋落叶在非生长季节和生长季节对林窗的响应具有明显差异。     

Reclassification of the serows and gorals: the end of a neverending story?

相似文献   

冬季雪被对青藏高原东缘高海拔森林凋落叶P元素释放的影响

雪被是影响高海拔森林凋落物分解的重要生态因子,其是否影响到生长季节与非生长季节凋落物中的P元素释放,尚未量化。为了量化季节性雪被对高海拔森林凋落物分解过程中P元素释放的影响,于2010年10月至2012年10月间,在青藏高原东缘川西高海拔森林不同厚度冬季雪被斑块下,设置凋落物分解袋实验。检测该地区代表性树种岷江冷杉(Abies faxoniana)、红桦(Betula albo-sinensis)、四川红杉(Larix mastersiana)和方枝柏(Sabina saltuaria)凋落叶在雪被覆盖不同关键时期(雪被形成前期、完全覆盖期和消融期)以及生长季节的P元素动态。结果表明,凋落物质量与雪被厚度均显著影响了P元素的释放过程。雪被覆盖时期凋落物P元素释放率表现为有雪被覆盖大于无雪被覆盖,而生长季节中除岷江冷杉外的其他3种凋落物P元素释放率均为无雪被覆盖下最大。相对于无雪被覆盖斑块,冬季雪被的存在提供了保护绝缘层,促进凋落物P元素释放,提高了各物种冬季P元素释放贡献率。这些结果表明,全球变化情景下的雪被减少可能减缓高海拔森林凋落物P元素的释放过程,改变森林土壤P元素水平。所以在研究高寒、高海拔地区全球气候变化下生态系统功能的工作中,应注重雪被这一异质性环境因子对生态系统功能的影响。