Japanese Alps Research Articles

The impact of climate on relief in the northern Japanese Alps within the past 1 Myr–The case of the Tateyama mountains

The impact of climate on mountain relief is often questioned, mainly due to the difficulties of measuring surface processes at the timescale of glacial-interglacial cycles. An appropriate setting for studying mountain erosion in response to Quaternary climate change is found in the Tateyama mountains in the Hida mountain range (northern Japanese Alps) due to distinct geomorphological features. The Japanese Alps uplifted within the past ∼1–3 Myr and experienced multiple glaciations during the late Quaternary. We use ultra-low temperature thermochronometers based on the luminescence of feldspar minerals from 19 rock samples and the electron spin resonance (ESR) of quartz minerals from 8 rock samples, in combination with inverse modelling to derive rock cooling rates and exhumation rate histories at 104–106 year timescales from three transects in the Tateyama region. While luminescence signals have already reached their upper dating limit, ESR signals (Al and Ti centres) yielded ESR ages of ∼0.3–1.1 Ma, implying surface processes active in the Pleistocene. Based on a negative age-elevation relationship, local relief reduction at a cirque-basin scale is identified over the past 1 Myr, whereas a positive age distribution with elevation for samples close to the mountain top does not follow this trend. Inverse modelling reveals rock cooling rates on the order of 20–70 °C/Myr, with slightly faster cooling for cirque-floor samples, which equate with erosion rates of 0.5–1 mm/yr that exceed rates from periglacial and slope processes in the same locality. Thus, our data suggest that Quaternary climate change coupled with distinct surface processes modified the slopes of the Tateyama mountains leading to a localised decrease in relief within an individual cirque basin over the second half of the Quaternary.

Comparative molecular analyses of Eimeria Schneider (Apicomplexa: Eimeriidae) species from rock ptarmigan in Iceland, Svalbard-Norway, and Japan.

The rock ptarmigan (Lagopus muta) has a Holarctic breeding distribution and is found in arctic and sub-arctic regions. Isolated populations and glacial relicts occur in alpine areas south of the main range, like the Pyrenees in Europe, the Pamir mountains in Central Asia, and the Japanese Alps. In recent decades considerable effort has been made to clarify parasite infections in the rock ptarmigan. Seven Eimeria spp. have been reported parasitizing rock ptarmigan. Two of those species, E. uekii and E. raichoi parasitizing rock ptarmigan (L. m. japonica) in Japan, have been identified genetically. Here we compare partial sequences of nuclear (18S rRNA) and mitochondrial (COI) genes and we detail the morphology of sporulated oocysts of E. uekii and E. raichoi from Japan, E. muta and E. rjupa, from the rock ptarmigan (L. m. islandorum) in Iceland, and two undescribed eimerian morphotypes, Eimeria sp. A, and Eimeria sp. B, from rock ptarmigan (L. m. hyperborea) in Norway (Svalbard in the Norwegian Archipelago). Two morphotypes, ellipsoidal and spheroidal, are recognized for each of the three host subspecies. Our phylogenetic analysis suggests that the ellipsoidal oocyst types, E. uekii, E. muta, and Eimeria sp. A (Svalbard-Norway) are identical and infects rock ptarmigan in Japan, Iceland, and Svalbard-Norway, respectively. Eimeria uekii was first described in Japan in 1981 so that E. muta, described in Iceland in 2007, and Eimeria sp. A in Svalbard-Norway are junior synonyms of E. uekii. Also, phylogenetic analysis shows that the spheroidal oocyst types, E. rjupa and Eimeria sp. B (Svalbard-Norway), are identical, indicating that rock ptarmigan in Iceland and Svalbard-Norway are infected by the same Eimeria species and differ from E. raichoi in Japan.

Differences in photosynthetic and water use characteristics of four co-existing tree species at the treeline of the Japanese Alps

ABSTRACT Physiological characteristics of trees in the alpine treeline are critical for assessing the vulnerability of alpine forest ecosystems, but differences in water relations between co-existing deciduous and evergreen trees remain poorly understood. In this study, we analyzed the photosynthetic and water use characteristics of two deciduous broad-leaved (Sorbus matsumurana and Betula ermanii) and two evergreen coniferous (Abies mariesii and Pinus pumila) tree species at the treeline – i.e. the line connecting the highest patches of forest composed of trees at least three meters high – of Mt. Norikura in central Japan, to explore the physiological adaptations of trees to alpine environments. We monitored diurnal changes in leaf gas exchange rates and leaf and soil water potentials in each tree species during the growing season, as well as bulk leaf water relations based on pressure – volume curves and whole-tree hydraulic structures. The four species under study relied on different physiological characteristics at both leaf and plant levels for adaptation to their natural habitat. For maintaining water in leaves, S. matsumurana showed higher water use efficiency (WUE; the ratio of photosynthesis to transpiration) and osmotic adjustment. In contrast, B. ermanii showed lower WUE, while maintaining higher soil-to-leaf hydraulic conductivity with less stomatal control. In turn, A. mariesii showed higher WUE and leaf succulence. Meanwhile, P. pumila showed lower WUE but compensated for water loss through higher leaf hydraulic capacitance and tissue elasticity. Our observations demonstrate that tree species rely on specific physiological characteristics to adapt to the alpine treeline environment.

Debris-flow activity in the Japanese Alps is controlled by extreme precipitation and ENSO – Evidence from multi-centennial tree-ring records

Japanese mountains are recurrently affected by mass movements and sediment-related disasters. Large efforts have therefore been undertaken to enhance understanding of the impacts and triggering of recent disasters, but ancient and continuous records to put recent events into perspective are still lacking. Here, we present a multi-centennial tree-ring-based debris-flow reconstruction in two size-contrasting torrential catchments of the Japanese Alps. We analyzed 197 affected trees growing on debris-flow fans and along torrential channels, which allowed us to identify 62 past events (38 and 24 in each catchment) from the late 19th century to today. The new chronology shows a non-stationary behavior of debris flows in the long-term, and an upward trend in debris flow activity over the last decades. Analysis of the 3-day rainfall legacy explains the occurrence of debris flows best, whereas rainfall thresholds show a positive trend linked to an increase in the occurrence of extreme precipitation over the last decades. Our results clearly support a link between debris flows with the passage of typhoons as well as La Niña events. The unprecedented length of the debris-flow record provided here opens new avenues for climate change and sediment-disaster research in Japan. Thus, our findings have important implications for the understanding of past, recent, and near-future debris-flow trajectories under climate change scenarios.

Seasonal diets of two rhinolophid bats, Rhinolophus nippon and Rhinolophus cornutus, in the southern Japanese Alps

Abstract Knowledge of diets is important for understanding species ecology and the mechanism of coexistence of multiple closely related species. Two rhinolophid bats, the greater Japanese horseshoe bat (Rhinolophus nippon) and the little Japanese horseshoe bat (Rhinolophus cornutus), occur in Japan, but little is known about their diets and interspecific interactions regarding food resources. In this study, we examined the fecal contents of these two species in the Southern Japanese Alps by microscopic analysis over multiple seasons. R. cornutus, which have more skillful flight, consumed nonvolant insects (caterpillars and spiders), whereas R. nippon did not; this indicates that R. cornutus can glean prey better than R. nippon. The larger-bodied R. nippon more frequently consumed hard-bodied beetles, whereas the smaller-bodied R. cornutus more frequently consumed soft-bodied dipterans and neuropterans. Body size differences influenced flight ability and bite force, which resulted in food resource partitioning and enabled multispecies coexistence of these closely related bats. A R. nippon nursery colony consumed a wider variety of insects, such as beetles, moths, and dipterans, during the pregnancy and lactation periods; however, after lactation, they showed a beetle-dependent diet, and before hibernation they again consumed various food resources. A R. cornutus non-nursery colony frequently consumed dipterans and moths in spring; dipterans, moths, and neuropterans in autumn; and moths and neuropterans in winter. These seasonal changes in diet seemed to be related to food supply or reproductive status.

Classification of Chubu-region dialects using random forest

The present study investigated how Japanese dialects in Chubu region are classified using random forest (RF) and an adaptive synthetic (ADASYN) sampling approach. We obtained the written-format pronunciations of 22 words from 884 Japanese speakers (average age = 71.1) who had been residing in their birthplaces. We calculated phonetic distance (ALINE distance) between the dialectal and standard Japanese pronunciations, and ran RF models with 1,000 bootstrap samples. The results of the RF models (ROC = 0.953, F1 = 0.68) demonstrated that speakers with a predicted probability greater than 50 percent (n = 415) were generally located in their residing prefectures, suggesting that each prefecture has its own dialect. Speakers with a predicted probability less than 50 percent were located in both their residing prefectures and the vicinities of the prefectures, particularly those in Aichi, Gifu, Shizuoka, Nagano, Gunma, and Niigata prefectures, suggesting that the speakers in the areas share some characteristics of the prefectural dialects. This potentially led to the poor predictions of the speakers. The expansion of these prefectural dialects seems to be limited by the Japanese Alps; dialects spoken on the eastern and western side of the mountain range are generally widespread only in the area, respectively.

Experimental evaluation of pathogenicity and acquired immunity of Eimeria species, E. uekii and E. raichoi, infecting Japanese rock ptarmigans in a subspecies of the birds

Japanese rock ptarmigans (Lagopus muta japonica) are birds that inhabit only alpine regions of central Honshu Island, Japan, known as the Japanese Alps. The number of these birds has recently declined, and in situ and ex situ national conservation programs for Japanese rock ptarmigans have been initiated. The infections of Eimeria spp. as protozoan parasites of the phylum Apicomplexa, E. uekii and E. raichoi, were frequently reported in the birds. However, the virulence of these Eimeria parasites has not been determined. Here, we analyzed the pathogenicity of these Eimeria parasites using experimental infections of a subspecies model of Japanese rock ptarmigans, Svalbard rock ptarmigans (Lagopus mutus hyperboreus), and evaluated acquired protective immunity against challenge in birds tolerant of low-dose inoculation with Eimeria parasites. Following inoculation with two Eimeria parasites derived from Japanese rock ptarmigans (dose range of 4 × 104 to 4 × 102 for E. uekii and 1.7 × 104 to 4 × 101 for E. raichoi), oocysts were detected at 6–8 days post-inoculation (PI), and the maximum number of oocysts per gram of feces was observed 7–10 days PI and then gradually decreased. The mortality rate and reduction in weight gain of chicks increased following high-dose inoculation of oocysts with abnormal feces (soft and diarrhea). Developmental zoites were detected histopathologically in epithelial tissues and sometimes the lamina propria from the duodenum to the colon. Chicks that survived low-dose inoculation did not show clear clinical symptoms after challenge inoculation. Our results suggest that the pathological characteristics of Eimeria parasites infecting Japanese rock ptarmigans include abnormal feces and reduction in weight gain, resulting in mortality in cases of heavy infection due to high-dose inoculation. These findings provide helpful data for Japanese rock ptarmigan conservation efforts.

Predicting Spruce Taiga Distribution in Northeast Asia Using Species Distribution Models: Glacial Refugia, Mid-Holocene Expansion and Future Predictions for Global Warming

Spruce taiga forests in Northeast Asia are of great economic and conservation importance. Continued climate warming may cause profound changes in their distribution. We use prognostic and retrospective species distribution models based on the Random Forest machine learning method to estimate the potential range change of the dominant taiga conifer Jezo spruce (Picea jezoensis (Siebold & Zucc.) Carrière) for the year 2070 climate warming scenarios and for past climate epochs–the Last Glacial Maximum (LGM) (~21,000 years before present) and the mid-Holocene Climatic Optimum (MHO) (~7000 years before the present) using the MIROC-ESM and CCSM4 climate models. The current suitable climatic conditions for P. jezoensis are estimated to be 500,000 km2. Both climatic models show similar trends in past and future ranges but provide different quantitative areal estimates. During the LGM, the main part of the species range was located much further south than today at 35–45° N. Projected climate warming will cause a greater change in the distributional range of P. jezoensis than has occurred since the MHO. Overlapping climatic ranges at different times show that the Changbai Mountains, the central parts of the Japanese Alps, Hokkaido, and the Sikhote-Alin Mountains will remain suitable refugia for Jezo spruce until 2070. The establishment of artificial forest stands of P. jezoensis and intraspecific taxa in the future climate-acceptable regions may be important for the preservation of genetic diversity.

A Long Way to Go ; From the Opposite Side of Northern Japanese Alps

A Long Way to Go ; From the Opposite Side of Northern Japanese Alps

Eustatic change modulates exhumation in the Japanese Alps

Abstract The exhumation of bedrock is controlled by the interplay between tectonics, surface processes, and climate. The highest exhumation rates of centimeters per year are recorded in zones of highly active tectonic convergence such as the Southern Alps of New Zealand or the Himalayan syntaxes, where high rock uplift rates combine with very active surface processes. Using a combination of different thermochronometric systems including trapped-charge thermochronometry, we show that such rates also occur in the Hida Mountain Range, Japanese Alps. Our results imply that centimeter per year rates of exhumation are more common than previously thought. Our thermochronometry data allow the development of time series of exhumation rate changes at the time scale of glacial-interglacial cycles, which show a fourfold increase in baseline rates to rates of ∼10 mm/yr within the past ∼65 k.y. This increase in exhumation rate is likely explained by knickpoint propagation due to a combination of very high precipitation rates, climatic change, sea-level fall, range-front faulting, and moderate rock uplift. Our data resolve centimeter-scale sub-Quaternary exhumation rate changes, which show that in regions with horizontal convergence, coupling between climate, surface processes, and tectonics can exert a significant and rapid effect on rates of exhumation.

Eustatic change modulates exhumation in the Japanese Alps

The exhumation of bedrock is controlled by the interplay between tectonics, surface processes, and climate. The highest exhumation rates of centimeters per year are recorded in zones of highly active tectonic convergence such as the Southern Alps of New Zealand or the Himalayan syntaxes, where high rock uplift rates combine with very active surface processes. Using a combination of different thermochronometric systems including trapped-charge thermochronometry, we show that such rates also occur in the Hida Mountain Range, Japanese Alps. Our results imply that centimeter per year rates of exhumation are more common than previously thought. Our thermochronometry data allow the development of time series of exhumation rate changes at the time scale of glacial-interglacial cycles, which show a four-fold increase in baseline rates to rates of ~10 mm/yr within the past ~65 k.y. This increase in exhumation rate is likely explained by knickpoint propagation due to a combination of very high precipitation rates, climatic change, sea-level fall, range-front faulting, and moderate rock uplift. Our data resolve centimeter-scale sub-Quaternary exhumation rate changes, which show that in regions with horizontal convergence, coupling between climate, surface processes, and tectonics can exert a significant and rapid effect on rates of exhumation.

Behavior of snow monkeys hunting fish to survive winter

Japanese macaques, Macaca fuscata, of Kamikochi in the Japanese Alps endure one of the coldest and harshest environments during winter when scarcity of food puts them at risk. However, various behaviors have evolved to mitigate potential mortality. These macaques typically eat bamboo leaves and the bark of woody plants in winter, but our previous study using the feces of Japanese macaques collected in the winter and DNA metabarcoding analysis revealed conclusively for the first time consumption of riverine benthos and brown trout. In this paper, we investigate how Japanese macaques hunt fish and collect these riverine biota by extensively observing their behavior, including the use of infrared sensor cameras. Many researchers have tracked Japanese macaques as part of behavioral and ecological studies, but previously the techniques by which Japanese macaques capture swimming fish has not been documented. Herein, for the first time we consider how novel macaque foraging behavior traits have evolved to secure valuable animal protein for winter survival when food resources are scarce.

The effects of late Cenozoic climate change on the global distribution of frost cracking

Abstract. Frost cracking is a dominant mechanical weathering phenomenon facilitating the breakdown of bedrock in periglacial regions. Despite recent advances in understanding frost cracking processes, few studies have addressed how global climate change over the late Cenozoic may have impacted spatial variations in frost cracking intensity. In this study, we estimate global changes in frost cracking intensity (FCI) by segregation ice growth. Existing process-based models of FCI are applied in combination with soil thickness data from the Harmonized World Soil Database. Temporal and spatial variations in FCI are predicted using surface temperature changes obtained from ECHAM5 general circulation model simulations conducted for four different paleoclimate time slices. Time slices considered include pre-industrial (∼ 1850 CE, PI), mid-Holocene (∼ 6 ka, MH), Last Glacial Maximum (∼ 21 ka, LGM), and Pliocene (∼ 3 Ma, PLIO) times. Results indicate for all paleoclimate time slices that frost cracking was most prevalent (relative to PI times) in the middle- to high-latitude regions, as well as high-elevation lower-latitude areas such the Himalayas, Tibet, the European Alps, the Japanese Alps, the US Rocky Mountains, and the Andes Mountains. The smallest deviations in frost cracking (relative to PI conditions) were observed in the MH simulation, which yielded slightly higher FCI values in most of the areas. In contrast, larger deviations were observed in the simulations of the colder climate (LGM) and warmer climate (PLIO). Our results indicate that the impact of climate change on frost cracking was most severe during the PI–LGM period due to higher differences in temperatures and glaciation at higher latitudes. The PLIO results indicate low FCI in the Andes and higher values of FCI in Greenland and Canada due to the diminished extent of glaciation in the warmer PLIO climate.

Blockslopes Caused by Large to Meso-scale Rock Slope Failures in the Upper Okumatajirodani Valley on the Eastern Side of Mount Maehotaka-dake North Ridge, Northern Japanese Alps

Blockslopes Caused by Large to Meso-scale Rock Slope Failures in the Upper Okumatajirodani Valley on the Eastern Side of Mount Maehotaka-dake North Ridge, Northern Japanese Alps

Characteristics of mountain glaciers in the northern Japanese Alps

Abstract. Since 2012, seven perennial snow patches in the northern Japanese Alps have been determined to be very small glaciers (VSGs: <0.5 km2). However, it had not been determined how such glaciers could be maintained in such a warm climate. In this study, we calculate the annual mass balance, accumulation depth, and ablation depth of five of these VSGs, covering 2015–2019 for four of them (2017–2019 for the fifth) using multi-period digital surface models (DSMs) based on structure-from-motion–multi-view-stereo (SfM–MVS) technology and images taken from a small airplane. The results indicate that, due to snow acquired from avalanches and snowdrifts, these VSGs are maintained by an accumulation in winter that is more than double that from the snowfall, thereby exceeding the ablation in summer. Therefore, we classify them as topographically controlled VSGs. We find very small yearly fluctuations in their ablation depth; however, their annual mass balance and accumulation depth have large yearly fluctuations. The annual mass balance, which mainly depends on the accumulation depth, showed accumulation throughout each glacier during heavy snow years and ablation throughout each glacier during light snow years. This characteristic differs from the upper accumulation area and lower ablation area that exists on most glaciers. These VSGs lack a positive annual mass balance gradient, which suggests that they are not divided by a distinct glacier equilibrium line altitude (ELA) into an upstream accumulation area and a downstream ablation area. Moreover, compared to other glaciers worldwide, we find the mass balance amplitude of VSGs in the northern Japanese Alps to be the highest measured to date.

Identification of Lagopus muta japonica food plant resources in the Northern Japan Alps using DNA metabarcoding.

DNA metabarcoding was employed to identify plant-derived food resources for the Japanese rock ptarmigan (Lagopus muta japonica), which is registered as a natural living monument in Japan, in the Northern Japanese Alps in Toyama Prefecture, Japan, in July to October, 2015–2018. DNA metabarcoding using high-throughput sequencing (HTS) of rbcL and ITS2 sequences from alpine plants found in ptarmigan fecal samples collected in the study area. The obtained sequences were analyzed using a combination of a constructed local database and the National Center for Biotechnology Information (NCBI) database, revealed that a total of 53 plant taxa were food plant resources for ptarmigans. Of these plant taxa, 49 could be assigned to species (92.5%), three to genus (5.7%), and one to family (1.9%). Of the 23 plant families identified from the 105 fecal samples collected, the dominant families throughout all collection periods were Ericaceae (99.0% of 105 fecal samples), followed by Rosaceae (42.9%), Apiaceae (35.2%), and Poaceae (21.0%). In all of the fecal samples examined, the most frequently encountered plant species were Vaccinium ovalifolium var. ovalifolium (69.5%), followed by Empetrum nigrum var. japonicum (68.6%), Kalmia procumbens (42.9%), Tilingia ajanensis (34.3%) and V. uliginosum var. japonicum (34.3%). A rarefaction analysis for each collection period in the study revealed that the food plant resources found in the study area ranged from a minimum of 87.0% in July to a maximum of 97.5% in September, and that 96.4% of the food plant taxa were found throughout the study period. The findings showed that DNA metabarcoding using HTS to construct a local database of rbcL and ITS2 sequences in conjunction with rbcL and ITS2 sequences deposited at the NCBI, as well as rarefaction analysis, are well suited to identifying the dominant food plants in the diet of Japanese rock ptarmigans. In the windswept alpine dwarf shrub community found in the study area, dominant taxa in the Ericaceae family were the major food plant s for Japanese rock ptarmigans from July to October. This plant community therefore needs to be conserved in order to protect the food resources of Japanese rock ptarmigans in the region.

Intraspecific independent evolution of floral spur length in response to local flower visitor size in Japanese Aquilegia in different mountain regions.

Geographic differences in floral traits may reflect geographic differences in effective pollinator assemblages. Independent local adaptation to pollinator assemblages in multiple regions would be expected to cause parallel floral trait evolution, although sufficient evidence for this is still lacking. Knowing the intraspecific evolutionary history of floral traits will reveal events that occur in the early stages of trait diversification. In this study, we investigated the relationship between flower spur length and pollinator size in 16 populations of Aquilegia buergeriana var. buergeriana distributed in four mountain regions in the Japanese Alps. We also examined the genetic relationship between yellow‐ and red‐flowered individuals, to see if color differences caused genetic differentiation by pollinator isolation. Genetic relationships among 16 populations were analyzed based on genome‐wide single‐nucleotide polymorphisms. Even among populations within the same mountain region, pollinator size varied widely, and the average spur length of A. buergeriana var. buergeriana in each population was strongly related to the average visitor size of that population. Genetic relatedness between populations was not related to the similarity of spur length between populations; rather, it was related to the geographic proximity of populations in each mountain region. Our results indicate that spur length in each population evolved independently of the population genetic structure but in parallel in response to local flower visitor size in different mountain regions. Further, yellow‐ and red‐flowered individuals of A. buergeriana var. buergeriana were not genetically differentiated. Unlike other Aquilegia species in Europe and America visited by hummingbirds and hawkmoths, the Japanese Aquilegia species is consistently visited by bumblebees. As a result, genetic isolation by flower color may not have occurred.

Spatiotemporal variations of snow cover in Mt. Norikura, the Northern Japanese Alps

Spatiotemporal variations of snow cover in Mt. Norikura, the Northern Japanese Alps

Newly Identifying Active Glaciers in the Northern Japanese Alps and Their Characteristics (English Translation)

Newly Identifying Active Glaciers in the Northern Japanese Alps and Their Characteristics (English Translation)

Winter diet of Japanese macaques from Chubu Sangaku National Park, Japan incorporates freshwater biota

The Japanese macaque (Macaca fuscata) is native to the main islands of Japan, except Hokkaido, and is the most northerly living non-human primate. In the Chubu Sangaku National Park of the Japanese Alps, macaques live in one of the coldest areas of the world, with snow cover limiting the availability of preferred food sources. Winter is typically a bottleneck for food availability potentially resulting in marked energy deficits, and mortality may result from famine. However, streams with groundwater upwelling flow during the winter with a constant water temperature of about 5 °C are easily accessible for Japanese macaques to search for riverine biota. We used metabarcoding (Cytochrome c oxidase I) of fecal samples from Japanese macaques to determine their wintertime diet. Here we provide the first robust evidence that Japanese macaques feed on freshwater biota, including brown trout, riverine insects and molluscs, in Chubu Sangaku National Park. These additional food sources likely aid their winter survival.