Invasion of the natural habitat of fragmented, secondary deciduous oak forests by greening/garden trees is frequently observed in urban areas of Japan. We investigated the flora of the invading greening/garden trees in such urban forests in the Hyogo, Osaka, and Saitama prefectures. There were more than 30 species of the invading trees in every region, and a total of 60 species were detected for all the regions. More than 70% of the invading species were bird-dispersed species, suggesting that the invasion of the forests by greening/garden trees is mainly caused by avian seed dispersal. The invading trees comprised many native species, and the number of these native species was approximately twice that of the invading alien species. The number of invading species correlated highly and positively with the area of the forest, regardless of the region. However, the species composition of the invading trees, expressed by sample scores obtained using detrended correspondence analysis, showed no significant relationship with the forest area in every region. In the Hyogo prefecture, most invading trees of 5 bird-dispersed species were found in forests that were located within a 200-m radius of the planted trees of the same species. This suggests that the extent of invasion of the forests by these species greatly depends on the distance from their seed source. Based on these results, we proposed certain measures to prevent greening/garden trees from invading and reproducing in the secondary deciduous oak forests.

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To establish a method for preserving mire vegetation, we evaluated the effects of forest clearance for cultivation land reclamation in the catchment area on the ditch reed community of Komado Mire, Fukushima Prefecture, Japan. The soil of the Japanese beech (Fagus crenata) forests in the catchment area of the mire was classified as moist brown forest soil (drier type) B_D(d) composed of a superficial Layer A (clay loam) and an underlying Layer B (clay). By contrast, the abandoned cultivation lands in the catchment area of the mire consisted of a superficial cultivated clay layer (Layer B) and an underlying intact clay layer (Layer B), both of which resembled Layer B of the Japanese beech forest soil in terms of nature and color. The area covered with ditch reeds in the periphery of the mire, adjoining the abandoned cultivation land in the catchment area, contained deposits of clay-like soil, resembling the soil of the abandoned cultivation land, on the peat layer. The ditch reeds growing along the stream that passed through the abandoned cultivation lands in the catchment area were taller than the ditch reeds growing along the stream that passed through natural forests in the catchment area. The EC, ash content, and pH were higher in the ditch reed-covered area along the stream that passed through the abandoned cultivation land in the catchment area. We found that the greater height of ditch reeds along the stream that passed through the abandoned cultivation land in the catchment area was due to the inflow of more mineral soil containing abundant inorganic elements, compared with the stream that passed through the natural forest. In conclusion, the forests in the catchment area played an important role in maintaining the mire vegetation by preventing the inflow of mineral soil into the mire.

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To clarify the species composition of vegetation established following aerial seeding after a wildfire, we investigated the vegetation in a burnt secondary forest five months after a wildfire (before aerial seeding) and again 40 months after aerial seeding with pasture plant species. Five months after the wildfire, the total coverage of vegetation was 1 to 17%, with vegetation established mainly by the vegetative growth of surviving burnt trees and, to a lesser extent, by seed germination. This vegetation consisted of secondary forest species and pioneer species. Forty months after aerial seeding, the total vegetation coverage had increased to 80 to 95%. This vegetation consisted mainly of sowed or planted species and was dominated by weeping lovegrass (Eragrostis curvula (Schrad.) Nees). It is thought that vegetation dominated by pasture plants was established and maintained for several years after aerial seeding following wildfires.

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To maintain viable populations of Northern Goshawk (Accipiter gentilis), it is essential to have knowledge of its abundance and distribution. We created a habitat model to predict the number of Northern Goshawk nests in 5×5 km cells established in and around the Kanto district, central Japan. From systematic nest surveys throughout 88 cells, we located 182 nests. Using the number of nests in these cells as a response variable, we generated a Poisson regression model with area of flatland, area of forest, area of urban land, and area of open land < 200 m from forest edge as explanatory variables. Multimodel inference based on Akaike's information criterion was used" to obtain parameter estimates. The model explained 57% of the deviance, indicating a good fit of the model to the data. When we tested the model prediction with validation data from two prefectures, the model successfully predicted which cells would have nests (predicted number of nests > 0.5) except for four cells in mountain regions in Shizuoka prefecture. These results suggest that the model can predict regional-scale distribution of nests in the Kanto district. We produced a map representing the number of nests across the Kanto district, in which the average number of nests in a cell was estimated as 1.25 and the total number as 2,909 (95% confidence interval: 1,699 - 5,196). The large confidence interval and a possibility of overestimation in these estimates should be taken into account when the estimates are used in Northern Goshawk conservation.

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The roles of Pronodularia japanensis and Corbicula spp. were studied experimentally to examine the cause of the decrease in Tanakia tanago in the Handa Miyakotanago protection area, Ootawara City, Tochigi Prefecture, central Japan. Tanakia tanago showed a clear preference for Pronodularia japanensis, while it rarely used Corbicula spp. as a host. Embryos were found at greater frequencies in the gills of Pronodularia japanensis collected from the Kuji River than in those collected from a small creek at Handa. The survival rate of embryos was also lower in the latter. These results suggest that the poor condition of mussels, due to water pollution in the Handa Miyakotanago protection area, was the reason for the decline in the population of Tanakia tanago in the late 1990s.

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Many bamboo stands planted for the production of bamboo sprouts have been abandoned. These abandoned bamboo stands have created an environmental problem: they are invading and replacing the surrounding vegetation. This has occurred in Mt. Toshima, Kumamoto Prefecture, where bamboo stands co-occur with evergreen broadleaf trees. Using Mt. Toshima as a model site, we studied the relationship between the expansion of bamboo stands from 1982 to 2003 and topographic conditions. Aerial photographs showed that the area of bamboo has increased considerably during this time. A field survey and computer simulation using cellular automata found that the annual rate of range expansion is 1.2 m/yr. Our analysis also showed that topographic factors clearly affect bamboo stand expansion: bamboo expansion on slopes and flat lands was greater than on ridges and steep slopes.

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We examined the impact of sika deer on the physical properties of soil and the underlying mechanisms in forests on the Boso Peninsula in surveys and a field manipulation experiment. In the broad-scale surveys, we measured soil hardness, litter mass, coverage by understory vegetation, and other environmental variables likely to affect soil properties. To identify causal relationships, we performed a path analysis, model selection using the Bayesian Information Criterion, and model averaging. In cedar forests, sika deer had no effect on soil hardness or litter mass. In cypress forests, sika deer affected the soil properties indirectly by decreasing the understory cover, while they affected hardwood forests directly. Removing the understory plants preferred by sika deer in the manipulation experiment increased soil and litter erosion and soil hardness in cypress plots, but not in cedar plots. This indicates that the impact of sika deer on the physical properties of soil varied among forest types, and the change in soil physical properties reflected the formation of a soil surface crust by raindrops and soil erosion. These changes in soil properties could lead to regime shifts in forest ecosystems, which should be examined in the future.

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To evaluate the impact of global warming on tree phenology, components of leaf phenology in 29 broad-leaved tree species in the warm temperate zone were observed for 7-10 years. The Cumulative Temperature (CT) method was used to predict the late stage of bud unfolding and mean leaf-fall date. For the late stage of bud unfolding, the prediction error for the indirect estimation approach, which adds the estimated leaf expansion period to the budburst date, was smaller than the direct estimation error using the CT method. For the mean leaf-fall dates, the estimation revealed significant effects in 7 of 15 deciduous broad-leaved species. The impact of global warming (1 to 4℃ uniform warming) on leaf phenology was simulated. For each ℃ of warming, the budburst date was accelerated by 3.4 d in evergreens and deciduous trees, the mean leaf-fall date was delayed 6.2 d (deciduous trees), and the photosynthetic period was prolonged by 10 d (deciduous trees).

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The specific traits (origin, use, introduction, and era) of naturalized vascular plants were examined. Of 2,237 introduced species, 1022 were weeds (ruderals), followed by ornamentals (863 species), medical plants (370), food plants (306), forage plants (224), plants that provided wood and other materials (161), or ground-cover (125). The species originating from East-Asia were mainly imported between 1601 and 1867 (Edo era), while those originating from Europe or North-America were mainly naturalized in 1868 - 1912 (Meiji era). The major use in the Edo era was as ornamentals, while the number of forage and ground-cover plants increased in the Meiji era. Of the ground-cover plants, 34.40% originated in Europe and 32.80% originated in East-Asia. Weeds (1,022 species) increased from the Edo era, and 36.69% of them were of European origin. The results suggest that when Japan opened after the Edo era, and again after World War II, large numbers of naturalized plants were introduced. The country of origin and use of the naturalized plants during each age roughly reflect the trade and industrial demand at that time.

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Tiger beetles (Coleoptera: Cicindelidae) are carnivorous insects that inhabit bare ground, such as eroded grasslands and river edges. Adults forage for small living animals in the daytime. Larvae live in burrows and ambush their prey. In Japan, six species of coastal tiger beetle occur at seashores, and two or three species co-occur in any one locality. In recent years, the natural coasts have declined drastically due to anthropogenic impact, and so have the numbers of coastal tiger beetles; such coastal species are listed in the red data books edited by the national and prefectural governments. Coastal tiger beetles have receieved attention as indicator insect species on seashores, and have been targeted for conversation by some local governments. This paper reviews the ecology, current habitat status, and conservation measures for coastal tiger beetles. Conservation measures targeting coastal tiger beetles will lead to the conservation of coastal ecosystems and biodiversity.

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The majority of investigations into increased CO_2 levels are limited to studies of the photosynthesis and respiration of leaves in forest ecosystems. However, temperature increases are predicted to be greater at higher latitudes and will affect virtually all chemical and biological processes. Therefore, ecosystem responses to global warming will be complex and vary temporally and spatially, due to direct and indirect effects. Field manipulations to examine the effects of global wanning have been conducted to determine the response of entire terrestrial ecosystems to an environmental variable in a manner that mimics climate change. Such ecosystem responses result from direct and indirect effects. Unlike mathematical modeling and laboratory investigations of climate change, field manipulations have the potential to provide valuable new insights into the effects of global warming. Recently, ecologists from around the world have started to undertake field manipulations to study global warming. This paper describes 1) the indirect effects and spatial and temporal variations in the impacts of global warming, 2) various types of ecological warming methods and ecosystem responses on a global scale based on a meta-analysis, 3) recommendations for future work, and 4) a field manipulation conducted in Tomakomai Experimental Forest using electric heating cables. The experimental results should help to devise countermeasures to global warming.

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When a population needs to be increased for habitat restoration, seed propagation is preferred to vegetative grown because it increases genetic diversity. In orchidaceous plants, seed propagation under natural conditions is not always successful. Only seeds sown in the presence of appropriate fungi will germinate, because orchid seeds require nutrition from mycorrhizal fungi for germination in their natural habitat. It is difficult to find the appropriate fungi in the field, and many orchid fungi are not known. In situ seed sowing techniques, which observe germination by burying and retrieving seed packets, constitute a valuable tool for detecting suitable fungi in the natural habitat. In this report, we used in situ seed sowing to detect mycorrhizal fungus using the endangered orchids Cymbidium macrorhizon and Cymbidium nipponicum. As a result, seed germination was observed in several packets and the distribution of fungi was determined successfully. Moreover, the appropriate depth and period for seed germination in the natural habitats were estimated. This technique provided useful information, such as suitable environmental conditions and seed dormancy, for assisting orchid research and conservation.

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The Asian black bear (Ursus thibetanus) on Shikoku Island is recognized as endangered because of its small population size. We assessed the genetic identity of bears on Shikoku using hairs collected from hair-traps, and investigated home ranges by radiotelemetry. Three hair-traps were set between May 2003 and December 2005, and DNA was extracted from the collected hairs. Then, we determined the genotypes of ten microsatellite regions using the polymerase chain reaction (PCR). Sex was determined from the genotypes of the amelogenin region. We set live-traps between July and September 2005, and captured two males and one female. The home ranges of the captured bears were investigated using very-high-frequency (VHF) radiotelemetry. Thirty-six hair samples were collected from the hair-traps. Over 8 of the 10 loci were amplified successfully in 17 of 36 hair samples. In these 17 hair samples, the genotypes of one and two samples were identical to those of the two captured male bears, respectively. Four hair samples were associated with one unidentified individual. No hair samples were associated with the captured female. We believe that hair-trap sampling is a practical method for assessing the genetic identity of bears.

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