Tetsuya Matsui

Climatic controls on distribution of Fagus crenata forests in Japan

Abstract We used classification tree analysis to develop a climate-based distribution model for Fagus crenata forests in Japan. Four climatic variables judged likely to affect the distribution of the species (summer and winter precipitation, minimum temperature of the coldest month and Kiras warmth index) were chosen as independent variables for the model. Latitudinal and longitudinal information was also used to examine effects of spatial autocorrelation on the model. The climatic factors associated with the distribution of the forests were analysed using a classification tree to devise prediction rules. Predicted areas of high probability for forest occurrence lay mainly on the Sea of Japan side of northern Honshu and southern Hokkaido. This is consistent with actual forest distribution. Some areas with high predicted probabilities of F. crenata forest occurrence were beyond the current natural northern range limits of these forests. Since these areas were widely scattered, it was assumed that the species has been hindered from colonizing them due to dispersal limitations. Deviance-weighted scores, used to compare magnitudes of the contributions of predictor variables, revealed winter precipitation as the most influential factor, followed by the warmth index, the minimum temperature of the coldest month and summer precipitation. Attempts were made to generate ecological explanations for the effects of the four climatic factors on the distribution of F. crenata forests. Abbreviations: CA = Classification accuracy; DWS = Deviance weighted score; JMA = Japan Meteorological Agency; MER = Misclassification error rate; TMC = Minimum temperature of the coldest month; NSNE = National Survey on the Natural Environment; OE = Omission error; PRS = Summer precipitation; PRW = Winter precipitation; RMD = Residual Mean Deviance; WI = Warmth index. Nomenclature: Ohwi & Kitagawa (1992).

Probability distributions, vulnerability and sensitivity in Fagus crenata forests following predicted climate changes in Japan

Abstract Question: How much is the probability distribution of Fagus crenata forests predicted to change under a climate change scenario by the 2090s, and what are the potential impacts on these forests? What are the main factors inducing such changes? Location: The major islands of Japan. Methods: A predictive distribution model was developed with four climatic factors (summer precipitation, PRS; winter precipitation, PRW; minimum temperature of the coldest month, TMC; and warmth index, WI) and five non-climatic factors (topography, surface geology, soil, slope aspect and inclination). A climate change scenario was applied to the model. Results: Areas with high probability (> 0.5) were predicted to decrease by 91 %, retreating from the southwest, shrinking in central regions, and expanding northeastwards beyond their current northern limits. A vulnerability index (the reciprocal of the predicted probability) suggests that Kyushu, Shikoku, the Pacific Ocean side of Honshu and southwest Hokkaido will have high numbers of many vulnerable F. crenata forests. The forests with high negative sensitivity indices (the difference between simulated probabilities of occurrence under current and predicted climates) mainly occur in southwest Hokkaido and the Sea of Japan side of northern Honshu. Conclusion: F. crenata forest distributions may retreat from some islands due to a high WI. The predicted northeastward shift in northern Hokkaido is associated with increased TMC and PRS. High vulnerability and negative sensitivity of the forests in southern Hokkaido are due to increased WI. Abbreviations: CCSR/NIES = Centre for Climate System Research / National Institute for Environmental Studies; DWS = Deviance-weighted score; GCM = Global Climate Model; IPCC = Intergovernmental Panel on Climate Change; JMA = Japan Meteorological Agency; MER = Misclassification error rate; NSNE = National Survey on the Natural Environment; PRS = Summer precipitation; PRW = Winter precipitation; TMC = Minimum temperatuire coldest month; WI = Warmth index. Nomenclature: Ohwi & Kitagawa (1992).

Climatic controls of a keystone understory species, Sasamorpha borealis, and an impact assessment of climate change in Japan

IntroductionThe aims of this study were to identify the climatic conditions controlling the distribution of Sasamorpha borealis and to assess the impact of climate change on the species in Japan.Materials and methodsThe relationship between S. borealis distribution and climatic variables in the Japanese Archipelago was explored using classification tree analysis. Potential habitat maps under the current and future climates were generated at about 1-km spatial resolution.ResultsThe model was highly accurate. Although snow cover has been thought to be the most important factor controlling S. borealis distribution, we revealed that the species requires high precipitation during the growing season even in humid Japanese environments. Areas with high summer (May–September) precipitation (PRS) were classified as potential habitat irrespective of other climatic conditions. In areas with moderate PRS, potential habitat was limited to cooler and less snow-covered areas and areas with low PRS were classified as non-habitat. The high fitness of the predicted to the observed distributions suggested that S. borealis could have survived throughout the Japanese Archipelago during the glacial period.ConclusionIn future climates, 29.0–39.1% of the current potential habitat was predicted to change to non-habitat due to increasing dryness in the growing season. Areas with high precipitation remained a potential habitat for S. borealis.

Potential effects of climate change on geographic distribution of the Tertiary relict tree species Davidia involucrata in China

This study, using species distribution modeling (involving a new approach that allows for uncertainty), predicts the distribution of climatically suitable areas prevailing during the mid-Holocene, the Last Glacial Maximum (LGM), and at present, and estimates the potential formation of new habitats in 2070 of the endangered and rare Tertiary relict tree Davidia involucrata Baill. The results regarding the mid-Holocene and the LGM demonstrate that south-central and southwestern China have been long-term stable refugia, and that the current distribution is limited to the prehistoric refugia. Given future distribution under six possible climate scenarios, only some parts of the current range of D. involucrata in the mid-high mountains of south-central and southwestern China would be maintained, while some shift west into higher mountains would occur. Our results show that the predicted suitable area offering high probability (0.5‒1) accounts for an average of only 29.2% among the models predicted for the future (2070), making D. involucrata highly vulnerable. We assess and propose priority protected areas in light of climate change. The information provided will also be relevant in planning conservation of other paleoendemic species having ecological traits and distribution ranges comparable to those of D. involucrata.

Habitats suitable for the establishment of Shorea curtisii seedlings in a hill forest in Peninsular Malaysia

Trees of the family Dipterocarpaceae dominate the emergent canopy of most lowland rain forests in Asia (Ashton et al . 1988). The family is, therefore, one of the most ecologically important in South-East Asia. Shorea curtisii Dyer ex King is the most common tree species in the hill dipterocarp forests of Peninsular Malaysia (Burgess 1975, Symington 2004), and is considered a key species for the dynamics of such forests. Currently, most Malaysian hill forests are selectively logged. Trees over 50 cm dbh are harvested, and any subsequent harvests depend on the remaining smaller trees. Such selective logging takes no account of seedling regeneration. Hence, subsequent timber harvests rely on trees derived from the seedlings that are already present and future seeds produced by the residual trees (Appanah & Mohd. Rasol 1994). Existing seedlings of S. curtisii in the forest, therefore, play a significant role in the dynamics of the hill forest. However, the conditions that constitute a suitable habitat for S. curtisii seedling establishment and survival remain unknown.

Land abandonment and changes in snow cover period accelerate range expansions of sika deer

Abstract Ongoing climate change and land‐use change have the potential to substantially alter the distribution of large herbivores. This may result in drastic changes in ecosystems by changing plant–herbivore interactions. Here, we developed a model explaining sika deer persistence and colonization between 25 years in terms of neighborhood occupancy and habitat suitability. We used climatic, land‐use, and topographic variables to calculate the habitat suitability and evaluated the contributions of the variables to past range changes of sika deer. We used this model to predict the changes in the range of sika deer over the next 100 years under four scenario groups with the combination of land‐use change and climate change. Our results showed that both climate change and land‐use change had affected the range of sika deer in the past 25 years. Habitat suitability increased in northern or mountainous regions, which account for 71.6% of Japan, in line with a decrease in the snow cover period. Habitat suitability decreased in suburban areas, which account for 28.4% of Japan, corresponding to land‐use changes related to urbanization. In the next 100 years, the decrease in snow cover period and the increase in land abandonment were predicted to accelerate the range expansion of sika deer. Comparison of these two driving factors revealed that climate change will contribute more to range expansion, particularly from the 2070s onward. In scenarios that assumed the influence of both climate change and land‐use change, the total sika deer range increased by between +4.6% and +11.9% from the baseline scenario. Climate change and land‐use change will require additional efforts for future management of sika deer, particularly in the long term.

Mapping of strength reduction of particleboard subjected to various climatic conditions using a climate deterioration index

The relationship between climatic factors and strength reduction of particleboard subjected to various climatic conditions at eight sites in Japan was investigated. Climatic factors such as mean temperature, sunshine duration, and precipitation were analyzed by principal component analysis. The first principal component score was introduced as a climate deterioration index (CDI). The particleboard strength reduced in high-CDI area. In this useful index for mapping deterioration zones, the CDI distribution was mapped. The strength reduction was predicted with multiple regression analysis using the CDI and exposure time, and the distribution of strength reduction after the outdoor exposure test was mapped as well. Strength reduced significantly in the southern area, particularly along the Pacific Ocean coast. The high-CDI area had high temperature and long sunshine duration. High temperature led to large strength reduction, and long sunshine duration accelerated the strength reduction process. Conversely, strength reduction in the northern area was smaller than that in the south. The mapping of CDI and strength reduction aided the understanding of the deterioration zone.

Projecting spatiotemporal changes in suitable climate conditions to regenerate trees using niche differences between adult and juvenile trees

Assessing suitable climate conditions to regenerate trees over a large area is of great importance to investigate potential impacts of climate change. In this study, we developed a size-based species distribution model (SBSDM) to assess spatiotemporal changes in the tree regeneration niche separately from the growth niche in adults. Siebold’s beech (Fagus crenata) was selected as the target species. We projected (1) areas where adult and juvenile potential habitats (PHs) overlapped, (2)only-adult PHs, (3) only-juvenile PHs, and (4) non-habitats for 2080–2099 using the SBSDM, a distribution dataset from the Phytosociological Relevé Database of Japan, and a future climatic dataset from 24 general circulation models (GCMs). We also projected juvenile PHs for all decades between 2011 and 2099 using four representative GCMs to assess potential lost decades of the regeneration niche. The SBSDM provided sufficient projections of adult and juvenile tree distributions as well as their niche differences under the current climate. Overlapping areas and only-adult PHs were projected to decrease by the end of this century. An increase in only-juvenile PHs was projected to occur in snowy regions, with juvenile PHs starting to decrease in warm and less snowy regions. Furthermore, juvenile PHs are expected to decrease widely around 2060 as well as at the end of this century due to considerable rapid warming around those times. We conclude that regeneration of F. crenata will start to decline in 2060, but snowy conditions will postpone the timing of the regeneration loss, causing an increase in only-juvenile PHs.

Potential distribution of pine wilt disease under future climate change scenarios

Pine wilt disease (PWD) constitutes a serious threat to pine forests. Since development depends on temperature and drought, there is a concern that future climate change could lead to the spread of PWD infections. We evaluated the risk of PWD in 21 susceptible Pinus species on a global scale. The MB index, which represents the sum of the difference between the mean monthly temperature and 15 when the mean monthly temperatures exceeds 15°C, was used to determine current and future regions vulnerable to PWD (MB ≥ 22). For future climate conditions, we compared the difference in PWD risks among four different representative concentration pathways (RCPs 2.6, 4.5, 6.0, and 8.5) and two time periods (2050s and 2070s). We also evaluated the impact of climate change on habitat suitability for each Pinus species using species distribution models. The findings were then integrated and the potential risk of PWD spread under climate change was discussed. Within the natural Pinus distribution area, southern parts of North America, Europe, and Asia were categorized as vulnerable regions (MB ≥ 22; 16% of the total Pinus distribution area). Representative provinces in which PWD has been reported at least once overlapped with the vulnerable regions. All RCP scenarios showed expansion of vulnerable regions in northern parts of Europe, Asia, and North America under future climate conditions. By the 2070s, under RCP 8.5, an estimated increase in the area of vulnerable regions to approximately 50% of the total Pinus distribution area was revealed. In addition, the habitat conditions of a large portion of the Pinus distribution areas in Europe and Asia were deemed unsuitable by the 2070s under RCP 8.5. Approximately 40% of these regions overlapped with regions deemed vulnerable to PWD, suggesting that Pinus forests in these areas are at risk of serious damage due to habitat shifts and spread of PWD.

Effects of climate change on potential habitats of the cold temperate coniferous forest in Yunnan province, southwestern China

We built a classification tree (CT) model to estimate climatic factors controlling the cold temperate coniferous forest (CTCF) distributions in Yunnan province and to predict its potential habitats under the current and future climates, using seven climate change scenarios, projected over the years of 2070-2099. The accurate CT model on CTCFs showed that minimum temperature of coldest month (TMW) was the overwhelmingly potent factor among the six climate variables. The areas of TMW<-4.05 were suitable habitats of CTCF, and the areas of -1.35 < TMW were non-habitats, where temperate conifer and broad-leaved mixed forests (TCBLFs) were distribute in lower elevation, bordering on the CTCF. Dominant species of Abies, Picea, and Larix in the CTCFs, are more tolerant to winter coldness than Tsuga and broad-leaved trees including deciduous broad-leaved Acer and Betula, evergreen broad-leaved Cyclobalanopsis and Lithocarpus in TCBLFs. Winter coldness may actually limit the cool-side distributions of TCBLFs in the areas between -1.35°C and -4.05°C, and the warm-side distributions of CTCFs may be controlled by competition to the species of TCBLFs. Under future climate scenarios, the vulnerable area, where current potential (suitable + marginal) habitats (80,749 km2) shift to non-habitats, was predicted to decrease to 55.91% (45,053 km2) of the current area. Inferring from the current vegetation distribution pattern, TCBLFs will replace declining CTCFs. Vulnerable areas predicted by models are important in determining priority of ecosystem conservation.