Sika Deer Population Research Articles

Feasibility assessment of active and passive acoustic monitoring of sika deer populations

Regardless of whether populations of sika deer (Cervus nippon) are native or introduced, their distribution continues to expand, presenting new ecological threats in several regions of the world, especially Japan. Consequently, there is growing demand for precautionary measures against such expansion, which is primarily associated with males during the initial stage of invasion. Therefore, the present study introduces two novel approaches—passive acoustic monitoring (PAM) and active acoustic monitoring (AAM)—to detect males with high sensitivity, using their howls during the rut. This study verifies the feasibility of these approaches by comparing them with existing methods based on spotlights and camera traps at five sites that support different deer densities. To validate PAM, we set unattended sound recorders to evaluate the time and variation in howl frequency at different sites. In addition, we measured the detection range of the howl. To verify AAM, we assessed whether sika deer males are vocally responsive to audio playbacks, and if so, the extent to which the frequency of the howl-back against different sound sources could explain male abundance. Both the PAM and AAM successfully detected males, even at sites with extremely low deer density where detection using existing methods failed. PAM had a detection zone of around 6ha in defoliated forests, which was >200-times greater than that of camera traps. The frequency of howl-back immediately after playbacks was higher than that of spontaneous howls; thus, AAM proved effective at explaining male abundance when using playbacks of real howls. In conclusion, our findings suggested that bioacoustic approaches could enhance the monitoring of low-density deer populations that might be in the initial stage of deer invasion or at the stage where the target density has been reached following population control.

Estimation of Population Density for Sika Deer (Cervus nippon) Using Distance Sampling in the Forested Habitats of Hokkaido, Japan

Sika deer (Cervus nippon) populations in Hokkaido have irrupted during the last three decades, causing severe damage to agriculture and forestry. Methods have been developed to estimate their population size on large but not on small scales. We estimated deer density using distance sampling to analyze the feasibility of employing the line-transect method in forested habitats on a management-district scale. Spotlight counts were conducted four times each year on the Iburi (IMD; 11 routes; 328.8 km total survey length) and Kushiro (KMD; 10 routes; 352.6 km) management districts in November 2013 and 2014. We observed 206 herds (302 deer) on the IMD and 680 herds (1,173 deer) on the KMD. Density estimates on the KMD, 39.6 ± 4.9 (average ± SE) in 2013 and 15.6 ± 2.3 in 2014, were significantly higher than those on the IMD, the former 8.4 ± 1.9 and the latter 4.4 ± 0.8. The line-transect method using distance sampling was useful for estimating deer density on the management-district scale. However, the large interannual variations of estimated density suggest that we have to specify the factors for annual variation in the future studies.

Analysis of the Development and Spatial Distribution of Sika Deer (Cervus Nippon) Populations on the Territory of the Czech Republic

This paper gives an analysis of the size of populations of sika deer (Cervus nippon) that were introduced to the Czech Republic at the end of the 19th century. Control methods are applied to underlying data taken from the official statistics of the Czech Statistical Office with the aim to check retrospectively their accuracy. Based on statistical data of third‑level territorial administrative units available, the recent population expansion of sika deer in the Czech Republic is evaluated as well as the manner and intensity of their spread into new, previously unpopulated areas. Results of applied control methods indicate errors in population management due to underestimation of overall population size data, in particular in the category of female deer.

Effects of an increase in population of sika deer on beetle communities in deciduous forests.

The overabundance of large herbivores is now recognized as a serious ecological problem. However, the resulting ecological consequences remain poorly understood. The ecological effects of an increase in sika deer, Cervus nippon Temminck (Cervidae), on three insect groups of beetles was investigated: ground beetles (Carabidae), carrion beetles (Silphidae), and dung beetles (Scarabaeidae and Geotrupidae) on Nakanoshima Island, Hokkaido, northern Japan. We collected beetles on Nakanoshima Island (experimental site) and lakeshore areas (control site) and compared the species richness, abundance, diversity index, and community composition of beetles between the sites. Results showed that although both species diversity and abundance of carabid beetles were significantly higher at the lakeshore site, those of dung and carrion beetles were higher at the island site. It was additionally observed that abundance of larger carabid beetles was higher at the lakeshore site, whereas that of small-sized carabid beetles did not differ between the lakeshore and island sites. For dung beetles, abundance of smaller species was higher at the island site, whereas that of large species did not differ between the lakeshore and island sites. Abundance of two body sizes (small and large) of carrion beetles were both higher at the island site. Overall, the findings of this study demonstrated that an increase in deer population altered the insect assemblages at an island scale, suggesting further changes in ecosystem functions and services in this region.

Comparison of Drive Counts and Mark-Resight As Methods of Population Size Estimation of Highly Dense Sika Deer (Cervus nippon) Populations

Assessing temporal changes in abundance indices is an important issue in the management of large herbivore populations. The drive counts method has been frequently used as a deer abundance index in mountainous regions. However, despite an inherent risk for observation errors in drive counts, which increase with deer density, evaluations of the utility of drive counts at a high deer density remain scarce. We compared the drive counts and mark-resight (MR) methods in the evaluation of a highly dense sika deer population (MR estimates ranged between 11 and 53 individuals/km2) on Nakanoshima Island, Hokkaido, Japan, between 1999 and 2006. This deer population experienced two large reductions in density; approximately 200 animals in total were taken from the population through a large-scale population removal and a separate winter mass mortality event. Although the drive counts tracked temporal changes in deer abundance on the island, they overestimated the counts for all years in comparison to the MR method. Increased overestimation in drive count estimates after the winter mass mortality event may be due to a double count derived from increased deer movement and recovery of body condition secondary to the mitigation of density-dependent food limitations. Drive counts are unreliable because they are affected by unfavorable factors such as bad weather, and they are cost-prohibitive to repeat, which precludes the calculation of confidence intervals. Therefore, the use of drive counts to infer the deer abundance needs to be reconsidered.

Mass emergence of a specialist sawfly species on unpalatable herbs under severe feeding pressure by sika deer

In recent years, the increase in sika deer populations has had a significant impact on forest ecosystems. Many studies have reported that this increase has led to the dominance of plants unpalatable to the deer; however, few studies have investigated the effects of this dominance on the specialist sawfly species that feed on the unpalatable plants. We observed the mass emergence of Aglaostigma amoorensis (Hymenoptera: Tenthredinidae), a rare specialist sawfly of the false helleborine Veratrum plants unpalatable to sika deer, in areas under severe feeding pressure by sika deer. An exponential increase in the number of emergent A. amoorensis adults was observed to occur with an increase in Veratrum album patch sizes. In addition, the increase in the A. amoorensis density had a negative effect on reproductive success of V. album. Our findings suggest that the relative abundance of specialist sawfly to the host-plant abundance has changed for successive years after sika deer irruption.

The tale of two deer: management of Père David’s deer and sika deer in anthropogenic landscape of eastern Asia

Père David’s deer (Elaphurus davidianus) and sika deer (Cervus nippon) occupy two contrasting types of niches in eastern Asia: Père David’s deer is a swamp deer adapted to wetlands, while the sika deer mainly live in forested areas. Both Père David’s deer and sika deer have been hunted since the early days of the hunting and gathering civilisation; however, these two deer have undergone different population histories. As human society entered the era of agriculture civilisation, Père David’s deer gradually lost its habitats to farmlands, and the population was greatly reduced until, finally, it became extinct in the wild in 1900. Fortunately, after 30 years of restoration and introduction, more than 4000 Père David’s deer thrive in nature reserves, zoos and safari parks in China, and more than 500 Père David’s deer could be found in the wild in 2014. Populations of wild sika deer were reduced as well due to hunting and deforestation, and were restricted in the forest patches in the mountains in eastern Asia. Nevertheless, the sika deer in China and Japan have different fortunes. Sika deer in China did not escape the prevalent tragedy of domestication, in that wild sika deer was endangered or extirpated in its original habitats, while the farmed sika deer thrived since late 1950s. Sika deer populations in Japan also remained at low density in the mid-1950s due to over-hunting, including poaching. After one-quarter of a century of in situ protection, sika populations are still small in China and some populations were found to leave the nature reserve to areas with high human densities, while the wild sika deer in Japan have markedly increased in numbers and extended their geographic distribution during the past few decades. Accordingly, the management strategies in China and Japan were completely different. The Chinese government is seeking all the efforts on the conservation of sika deer, while the Japanese government is revising laws to harvest and to reduce sika deer population.

A long-term study of the food habits of the Japanese marten in northern Kyushu, Japan, with reference to the increased population of sika deer

A long-term study of the food habits of the Japanese marten in northern Kyushu, Japan, with reference to the increased population of sika deer

Retrospective study of the medical status of 34 Formosan sika deer (Cervus nippon taiouanu) at the Taipei Zoo from 2003 to 2014

Abstract : The Formosan sika deer (Cervus nippon taiouanus) is an endemic subspecies in Taiwan. The original wilddeer has been extinct since the late 1960s. The largest captive population is located at the Taipei Zoo. Except forinfectious disease outbreaks, no systemic medical research has been reported for this subspecies. This study wasconducted to analyze the medical status of the captive Formosan sika deer population, including the hematologicaland serum chemistry characteristics. To accomplish this, medical records for 34 Formosan sika deer from January2003 to January 2014 were acquired and analyzed. The most common illness and cause of death was trauma, followedby gastrointestinal and respiratory disease, respectively. The hematologic and serum chemical values of healthy adultswere quite different from those of sika deer (Cervus nippon yesoensis). This study provides a closer medicalunderstanding of this subspecies and the results will facilitate its management.Keywords : Formosan sika deer, gastrointestinal disease, respiratory disease, Taiwan, trauma

Significance of woody browse preferences in evaluating the impact of sika deer browsing on tree seedlings

The growing populations of sika deer (Cervus nippon yesoensis) in Hokkaido, Japan, are having increasingly negative impacts on forests. Although the percentage or frequency of browsed twigs and seedlings is a useful index of the impact of deer on forests, differences in the browse preferences of deer among tree species should also be considered. We evaluated the woody browse preferences of sika deer and examined a method for evaluating deer impacts based on the occurrence of browsing scars on seedlings, together with browse preferences. We also validated the percentages of browsed seedlings irrespective of browse preferences as an index of deer impact. We measured the heights of seedlings 30–200 cm tall in five 5 × 20 m plots located in Abies sachalinensis plantations in each of seven tracts and recorded browsing damage that occurred on leader shoots of seedlings. Browse species preference was evaluated using a generalized linear model (GLM) that included the seven tracts, species, and seedling height as explanatory variables. The results of the GLM suggest that differences in browse preferences among species are continuous and cannot be categorized discretely. The tract coefficients are considered to be an index of deer impact levels and can be estimated from the percentage of browsed seedlings for a species if the species coefficient is given. Simple percentages of browsed seedlings can also be used as an index of impact level, regardless of browse preferences, though these may be inaccurate, especially when the site is dominated by significantly preferred or avoided species.

ニホンジカ低密度実現・維持に向けた課題：捕獲とモニタリングを中心に

ニホンジカ低密度実現・維持に向けた課題：捕獲とモニタリングを中心に

Temporal changes in molar wear rate of a sika deer population under density‐dependent food limitation

AbstractNegative effects of density‐dependent food limitation on molar wear rate in ungulate populations, as well as unworn molar size and its sex differences in ruminants, have been studied for a long time. However, these studies were based on comparisons of populations from different districts or habitats. If drastic changes in food habits and life history occurred under density‐dependent resource limitation, it is of great interest whether this change caused temporal changes in molar wear rate, and whether the degree of hypsodonty changed under this short but intensive selective pressure. We examined the temporal change in molar wear rate using long‐term monitoring data of a sika deer (Cervus nipon) population on Nakanoshima Island, Hokkaido, Japan. Corresponding to the change in food habits, the molar wear rate changed mainly because of the amount of soil that was secondarily ingested when deer fed on fallen leaves. Molar wear rate was the fastest level after the first population crash on Nakanoshima Island among extant sika deer populations. Nevertheless, we did not find any evidence of increased hypsodonty in Nakanoshima deer. It is possible that natural selection for increased molar durability (hypsodonty) has been working on Nakanoshima deer, but the adaptive change has not yet appeared at a statistically significant level.

Within-island local variations in tooth wear of sika deer (Cervus nippon centralis) in northern Japan

Geographical variations in feeding habits of mammals are usually known from field observation. However, using proxies such as tooth wear (mesowear and microwear), other studies also permitted to indirectly infer dietary traits of populations. Tooth mesowear which indicates the diet over a long temporal scale (the last weeks or months) and tooth microwear which reflects the diet over a short temporal scale (the last days or weeks) were employed to identify differences in diets at large scales. The objective of this study is to test for local variations in diet by comparing populations of sika deer (Cervus nippon centralis) from five small areas on Kinkazan Island, northern Japan. Results indicate that tooth mesowear averages the feeding habits over long periods of time and consequently is not appropriate to identify local differences. On the contrary, tooth microwear permitted to distinguish significant differences in wear patterns. Tooth microwear analysis has shown that even on a small island like Kinkazan, local variations in feeding habits of sika deer could be identified. Therefore microwear is a proxy suitable to the study of feeding habits of ungulates at small geographical scale.

Efficient management for the Hokkaido population of sika deer Cervus nippon in Japan: accounting for migration and management cost

AbstractWe evaluated the fourth stage of the “Conservation and Management Plan for Sika Deer (Cervus nippon) in Hokkaido, Japan (CMPS4)”, focusing on its cost‐effectiveness and sika deer migration between two management areas of eastern and western Hokkaido. To clarify these factors, we constructed a stochastic matrix population model that accounts for deer migration and several uncertainties. We assumed four different budget scenarios and simple rules regarding nuisance control, and simulated four alternative management strategies. In the stochastic simulation, we calculated the probability of successfully satisfying the population target given by the CMPS4, an average total actual management cost, and a cost‐effectiveness index given four budget conditions of migration rate and budget allocation ratio. The simulation results suggest the following. First, the current management budget is so small that the probability of successfully satisfying the population targets in both areas is only 26–30 %. If the total budget remains small, it should be almost entirely invested in one area, regardless of migration situation, to maximize the probability of successfully meeting the target density in at least that area. However, these probabilities of success decrease with greater migration rate. Second, when the government invests more of its budget in the early management stage, the expected total actual cost decreases and the probability of management success increases. These findings represent cost‐effective management strategies for satisfying the CMPS4 targets.

Effects of population density and snow depth on the winter diet composition of sika deer

ABSTRACTThe understanding of population density and weather effects is fundamental for evaluating the population dynamics of ungulates. However, studies focusing on temporal variations in diet composition are limited. We investigated the effects of population density and snow depth on variation in the winter diet composition of 2 contrasting sika deer (Cervus nippon) populations in Oku‐Nikko and Ashio, Tochigi Prefecture, central Japan by monitoring diet composition for ≥15 years. The main food in Oku‐Nikko was dwarf bamboo (Sasa nipponica), which has a high crude protein content. This plant sometimes had low availability because of the combination of snow accumulation and reduced culm height associated with chronic grazing. The main food in Ashio was Japanese pampas grass (Miscanthus sinensis), which has a low crude protein content, but its availability was high because of high culm height and little snow accumulation. In Oku‐Nikko, snow accumulation and high deer density negatively affected the proportion of dwarf bamboo found in rumen contents, with the most significant effect found in calves. In Ashio, Japanese pampas grass composed a relatively high and constant proportion of the rumen contents when snow accumulation was ≤50 cm; however, it was negatively affected by snow accumulation of >50 cm. In addition, the utilization of Japanese pampas grass was reduced only when deer density was extremely high (>150 deer/km2). Our results clearly demonstrate that absolute density is not the sole factor that affects variation in the winter food selection of sika deer. The combined effects of snow depth and habitat quality, such as vegetation height, are overwhelmingly important in determining the winter diet composition of sika deer populations. © 2015 The Wildlife Society.

Cooperative capturing scheme to reduce sika deer population in Shiretoko

Cooperative capturing scheme to reduce sika deer population in Shiretoko

Evidence of pre-introduction hybridization of Formosan sika deer (Cervus nippon taiouanus) on Okinoshima, Wakayama Prefecture, Japan, based on mitochondrial and nuclear DNA sequences

To examine the origin of the Formosan sika deer (Cervus nippon taiouanus) introduced to the island of Okinoshima (Wakayama Prefecture, Japan), sixteen tissue samples from Okinoshima population were analyzed to determine sequence variation in maternal mitochondrial DNA (mtDNA) cytochrome b and nuclear DNA α-lactalbumin (αLAlb). Three cytochrome b haplotypes were found in the Okinoshima population, two Formosan sika deer haplotypes and one Formosan sambar (C. unicolor swinhoei) haplotype. Three nuclear DNA αLAlb sequences, i.e. Formosan sika deer, red deer (C. elaphus), and additional one unknown sequence were detected in the population. Cytonuclear disequilibrium was observed in five individuals, indicating that the Okinoshima population have occurrence of hybrid among the three deer species. The deer introduced on Okinoshima might have originated from a private deer-breeding facility in Taiwan. To avoid native Japanese sika deer (e.g. C. n. centralis) genetic introgression, the Okinoshima population should be isolated from native Japanese sika deer populations.

Genetic diversity and population structure of a Sichuan sika deer (Cervus sichuanicus) population in Tiebu Nature Reserve based on microsatellite variation.

Cervus sichuanicus is a species of sika deer (Cervus nippon Group). To date, research has mainly focused on quantity surveying and behavior studies, with genetic information on this species currently deficient. To provide scientific evidence to assist in the protection of this species, we collected Sichuan sika deer fecal samples from the Sichuan Tiebu Nature Reserve (TNR) and extracted DNA from those samples. Microsatellite loci of bovine were used for PCR amplification. After GeneScan, the genotype data were used to analyze the genetic diversity and population structure of the Sichuan sika deer in TNR. Results showed that the average expected heterozygosity of the Sichuan sika deer population in TNR was 0.562, equivalent to the average expected heterozygosity of endangered animals, such as Procapra przewalskii. Furthermore, 8 of 9 microsatellite loci significantly deviated from the Hardy-Weinberg equilibrium and two groups existed within the Sichuan sika deer TNR population. This genetic structure may be caused by a group of Manchurian sika deer (Cervus hortulorum) released in TNR.

Bamboo feeding and tooth wear of three sika deer (Cervus nippon) populations from northern Japan

Sika deer (Cervus nippon) in the Japanese archipelago are cervids known to have high ecological plasticity, which is reflected in latitudinal variation in their feeding habits. The northern populations are grazers that depend on dwarf bamboos, whereas the southern ones feed on browse and fruits. These differences in plant composition of the diet should affect the tooth wear patterns because the different plants have different concentrations and morphologies of phytoliths (microscopic silica bodies that precipitate in and around cells in many plants). We studied 2 mainland populations (Mt. Goyo and Oshika Peninsula) and 1 island population (Kinkazan Island) of sika deer from northern Japan to understand how dwarf bamboo (Sasa nipponica and Sasamorpha borealis) affects tooth wear on the mainland populations in comparison to the lawn grass (Zoysia japonica) consumed by the island population. Fruits are not considered in this study because only northern populations are examined. The combined analyzes of tooth mesowear and microwear permitted us to detect seasonal differences in the feeding habits of sika deer. The tooth wear pattern also reflected differences directly related to the type of plant ingested. The grass Zoysia japonica, available on Kinkazan Island, had a highly abrasive effect on sika deer enamel. The bamboo species S. nipponica and S. borealis, more abundant on the Mt. Goyo and Oshika Peninsula areas, respectively, were less abrasive than Z. japonica. Differences also were detected in the wear patterns produced by the 2 species of bamboo. Tooth mesowear suggests that S. nipponica is more abrasive than S. borealis, which was confirmed by the high phytolith content found in the plant, especially in the stem of S. nipponica, the part consumed by the sika deer in late winter.

Home range size and spatio-temporal dynamics of male sika deer (Cervus nippon; Cervidae, Artiodactyla) in an introduced population

The sika deer (Cervus nippon) is native to Japan and East Asia and has been introduced almost worldwide. Despite the wide distribution of the species, only few studies on its home range in non-native areas have been conducted. We focused on home range size and its seasonal and spatial dynamics in an introduced sika deer population in the Doupovské hory Mts., north-western Czech Republic. The mean home range size, obtained from ten subadult and adult males, was 3620 ha using the minimum convex polygon method, 1163 ha using the Brownian bridges method, and 819 ha using kernel estimation. The mean intra-individual home range overlap from month to month was about 72 %, but decreased to 28 % when calculated for three-month periods. The unusually large home range sizes observed can be explained by a relatively low population density of the sika deer in the study area and possibly by the non-territorial mating strategy of males. The high values of seasonal home range overlap together with the time series of the monthly home range maps indicate some positional shifts but do not support presence of seasonal migration.