Temperate Forest In Japan Research Articles

Comparison of stream benthic invertebrate particularly stonefly assemblages in the temperate forest in Japan in relation to forest types

There have been recent investigations on the effects of different Japanese forest types on benthic invertebrate assemblages. In this study, the difference of stonefly assemblage between the two forest types, i.e. natural broad-leaved forest and planted coniferous forest, was clarified at the genus level for both larvae and adults. Differences were manifested in both larval and adult stonefly assemblages. The abundance of some larval stonefly genera varies by forest composition, and this tendency was the same with that of adult stonefly genera. There are few natural forests left in western Japan. If remaining natural broad-leaved forest were to be converted to coniferous plantations, one of the species that inhabit natural forest streams may become extinct.

Fern–spore‐feeder interaction in temperate forests in Japan: Sporing phenology and spore‐feeding insect community

Angiosperms are widely appreciated to have flowering schedules, but far less attention has been paid to the timing of spore production by ferns. Although a range of abiotic factors are likely responsible for the timing of fern sporing, spore predation by specialist spore-feeding insects may also exert selective forces on timing. As a step toward understanding ecological factors that affect the evolution of fern sporing phenology, we tracked annual sporing patterns and examined associations with spore-feeding insects in 38 ferns species in two Japanese temperate forests. Most sporing occurred during June through August, the period of highest temperature and precipitation at the study sites, but some species produced spores during a limited period in spring or very late autumn. Over 70% of all species examined were attacked by spore-feeders, which consisted of seven polyphagous and five oligophagous species. Spore feeders occurred predominantly during June through September, and stathmopodid moth larvae consumed up to 70% of the mature sporangia. Thus, although the warm and humid conditions in the summer is likely favored for prothallial growth and fertilization, spring or late-autumn sporing in some species may have evolved as an adaptation to escape spore predation by spore feeders.

Pathogen attack and spatial patterns of juvenile mortality and growth in a temperate tree, Prunus grayana

To examine whether the Janzen–Connell hypothesis is valid in temperate forests, we investigated the density, growth, mortality, and agents of mortality of seedlings and the density, size, and age of saplings of Prunus grayana Maxim. at three distances (0–3, 6–10, and 16–26 m) from conspecific adults in a temperate forest in Japan. An inoculation experiment was also conducted to test the host range of a leaf pathogen. The probability of mortality was highest at 0–3 m during the first 2 years of growth. Mortality mainly resulted from distance-dependent attack by two types of pathogen that caused damping-off epidemics and spot symptoms on leaves. The leaf pathogen was identified as Phaeoisariopsis pruni-grayanae Sawada, which infected many more seedlings of Prunus grayana than of the two other tree species tested in an inoculation experiment. The vertical and diameter growth was lowest at 0–3 m and highest at 16–26 m in both seedlings and saplings. As a result, the greatest number of large and older saplings was observed at 16–26 m. Our results demonstrate that the Janzen–Connell mechanism operates in a beech-dominated forest in the temperate region of Japan.

Intraspecific Variation in Leaf Life Span for the Semi-evergreen Liana Akebia trifoliata is Caused by Both Seasonal and Aseasonal Factors in a Temperate Forest

We investigated the leaf demography of a temperate woody liana, Akebia trifoliata, in a temperate forest in Japan, Akebia is semi-evergreen: some leaves are shed before winter, while others remain through the winter. Previous studies of semi-evergreen species found that variation in leaf life span was caused by variation in the timing of leaf emergence, Leaves that appeared just before winter over-wintered, while leaves appearing earlier were shed, However, it is unclear whether leaves of the same cohort (i.e., leaves that appear at the same time within a single site) show variation in life span under the effect of strong seasonality. To separate variation in life span among the leaves in each cohort from variation among cohorts, we propose a new method - the single leaf diagram, which shows the emergence and death of each leaf. Using single leaf diagrams, our study revealed that Akebia leaves within a cohort showed substantial variation in life span, with some over-wintering and some not. In addition, leaves on small ramets in the understory showed great variation in life span, while leaves on large ramets, which typically reach higher positions in the forest canopy, have shorter lives, As a result, small ramets were semi-evergreen, whereas large ramets were deciduous, The longer lives of leaves on small ramets can be interpreted as a shade-adaptive strategy in understory plants.

Analysis of methane production pathways in a riparian wetland of a temperate forest catchment, using δ13C of pore water CH4 and CO2

To clarify how hydrological processes affect biogenic methane (CH4) production and emission from soil surfaces, we analyzed the δ13C of CH4 and CO2 and chemical constituents dissolved in groundwater at a wetland in the headwater catchment of a temperate forest in Japan. We estimated the contribution of acetate fermentation using the δ13C isotope mass balance of dissolved CH4 and CO2. CH4 production pathways (e.g., acetate fermentation and carbonate reduction) changed temporally and spatially with hydrologically controlled redox conditions. The proportion of methanogenesis attributable to acetate fermentation usually decreased with temperature, suggesting that carbonate reduction dominated under conditions of high CO2 concentration. In particular, the groundwater table and summer temperatures were key controlling factors in the interannual and intra‐annual changes in CH4 production pathways, controlling oxygen supply and consumption and, therefore, redox conditions in the soil. Under high temperature and high water table conditions during summer, the soil was strongly reduced and the proportion of carbonate reduction increased. Acetate fermentation also increased episodically, resulting in sporadic increases in δ13C‐CH4. The calculated acetate contribution obviously decreased in periods of low water table and high temperature when the soil surface was relatively oxic, implying deactivation of acetoclastic methanogenesis under oxic conditions. Thus, hydrological processes control the supply of these electron donors and acceptors and therefore play an important role in determining the relative proportions of CH4‐producing pathways. Our results also indicate that an increase in acetate contribution under highly reducing conditions stimulates CH4 production and emission from the soil surface.

Morphological differentiation of current‐year shoots of deciduous and evergreen lianas in temperate forests in Japan

AbstractMorphological variation in current‐year shoots within plants was examined in five deciduous and four evergreen liana species from temperate forests in Japan to elucidate the role differentiation in shoots. All lianas had both shoots that twined or developed adventitious roots to gain support on host materials (searcher shoots) and self‐supporting shoots with no climbing structures (ordinary shoots). Searcher shoots were 20–295 times longer than ordinary shoots. The allometric relationships between stem length and leaf area differed between searcher and ordinary shoots, and the stem length for a given leaf area was greater in searcher shoots. Leaf area per shoot mass was 1.4–4.3 times higher in ordinary shoots because of the greater allocation to leaf biomass. Searcher shoots comprised only 1–6% of total shoots but 30–85% of total shoot length in deciduous lianas. Ordinary shoots accounted for 70–95% of the total leaf area in these liana species. These results suggest that the exploration of new space was primarily achieved by searcher shoots, whereas a large proportion of current photosynthetic production was achieved by ordinary shoots. The range of stem length and leaf mass ratio of ordinary shoots was similar to that in shoots of tree species. Specialization of shoots in lianas is discussed.

Development and characterization of polymorphic microsatellite DNA markers for Sasa senanensis (Poaceae: Bambuseae)

Sasa senanensis is a dwarf bamboo species distributed on the floors of cool temperate forests in Japan and adjacent regions. We isolated eight polymorphic microsatellite loci from this species. The number of alleles ranged from two to eight and the observed heterozygosity per locus from 0.13 to 0.74. Seven of the eight loci were also polymorphic in Sasa nipponica. Most of these markers were successfully amplified in other dwarf bamboo species. These markers will be useful for investigating clonal structure and population genetics in some dwarf bamboo species.

Effects of population density, sex morph, and tree size on reproduction in a heterodichogamous maple, Acer mono, in a temperate forest of Japan

AbstractThe effects of local population density, sex morph [protogynous (PG) or protandrous (PA)], and individual tree size on the demographic processes of seed production were investigated in a heterodichogamous maple, Acer mono Maxim. var. Marmoratum (Nichols.) Hara f. dissectum, in a temperate forest of Japan. As the distance from conspecific reproductive adults increased, the percentage of immature seed fall and empty seeds increased significantly, indicating higher pollination success along with local population density. Although the difference was not distinct, pollination success was affected by the local population density of the reciprocal sex morph rather than that of both sex morphs. The trees at higher local population density sites suffered higher seed mortality due to predation and decay, and tended to produce smaller seeds. Thus, the impacts of local population density operated both positively and negatively on reproduction. As a factor of individual traits, tree size scarcely affected any demographic processes. On the other hand, sex morph did affect pollination success. Trees of PG type had lower immature seed fall than those of PA type, suggesting that the former has higher efficiency of pollen acceptance than the latter. The results on seed demography presented here partly support previous suggestions that heterodichogamous plants exhibit reciprocal cross‐pollination and gender specialization as reproductive traits.

Longitudinal patterns of benthic invertebrates along a stream in the temperate forest in Japan: in relation to humans and tributaries

Abstract. The relationship between benthic invertebrate assemblage composition and surrounding land use has been examined in various ways, but most studies are undertaken at a coarse scale, or they compare obviously different landscapes. In Japan, these obvious differences in landscape are rare, and humans reside even in remote montane areas. In order to clarify the influence of human residence on benthic invertebrate assemblages, seasonal and site differences among benthic samples collected from a 15‐km stretch of Kuroson Stream and their relation with riparian land use were examined. The number of individuals and genera differed significantly both spatially and temporally. Multivariate assemblage structure also differed significantly across space and time along the stream. Increase of residential areas affected the in‐stream benthic invertebrate assemblage. Site differences along the stream and the effect of human residence were not masked by the potentially homogenizing influence of tributary streams. The composition of surrounding vegetation was the most important factor influencing benthic community structure. The presence or absence of human residential areas and seasonal change were also important variables. Benthic invertebrates may be carried and migrate to main streams from tributaries; however, this phenomenon was not observed. Assemblages of benthic invertebrates that inhabit a particular site do not change and are considered to vary seasonally across a certain range.

Dynamics of fruit-body production and mycorrhiza formation of ectomycorrhizal ammonia fungi in warm temperate forests in Japan

To investigate the quantitative correlation between dynamics of ectomycorrhiza (ECM) formation and fruit-body production of the ammonia fungi, we treated forest soils in two ECM forests, a Castanopsis cuspidata forest and a Quercus serrata forest, in warm temperate Japan with urea to induce fruiting of ammonia fungi. We identified the ectomycorrhizae of two known species of ammonia fungi, Alnicola lactariolens and Hebeloma vinosophyllum, using morphological typing and PCR-RFLP. ECM initiation, increase, and subsequent decrease preceded the start, increase, and decrease of fruit-body production for each species. We also found many kinds of ECM fungi that did not develop fruit bodies after urea treatment during the observation period, which suggests that it is necessary to expand the definition of ammonia fungi from one that refers solely to the species reproducing on the ground to one which includes those in somatic forms in the soil.

Dynamics of fruit-body production and mycorrhiza formation of ectomycorrhizal ammonia fungi in warm temperate forests in Japan

Dynamics of fruit-body production and mycorrhiza formation of ectomycorrhizal ammonia fungi in warm temperate forests in Japan

Age structure of wind-felled canopy trees for Siebold's beech (Fagus crenata) in the northernmost population in Karibayama, Hokkaido

To determine the lifespan of Siebold's beech (Fagus crenata), a dominant canopy tree species of the cool temperate forests of Japan, we estimated the age of 33 mature beech trees felled by a large typhoon in September 2004 at Karibayama, in southern Hokkaido. The study site lies within one of the northernmost distributions of Siebold's beech populations in Japan. We counted tree rings from tree disks at a height of 1 m, and diameter growth was measured in annual increments. The sample age revealed two major peaks at 240 and 175 years. The diameter growth was good between 40 and 60 years of age and gradually decreased after 70 years of age. Annual diameter increments were noticeably small in good fruiting years, indicating a large allocation of annual carbon gains to the reproductive organs. Bud scale counts of juvenile trees revealed that the age at which the height reached 1 m was approximately 6–13 years. The lifespan of Siebold's beech in the Karibayama population was therefore estimated to be approximately 250 years, an estimation that is higher than that previously reported for this species in the northernmost populations.

Fungal content of ectomycorrhizal tips: comparison among 13 tree species

To better understand soil carbon cycling in forest ecosystems, we studied the proportion of fungal sheath area (FSA) in the cross-sectional ectomycorrhizal area in 13 tree species. Ectomycorrhizal samples were collected from subalpine and temperate forests in Japan. The FSA values were in the range of 12% to 56% across all tree species, tree ages, and fungal species. In Abies firma and Quercus serrata, the FSA values were larger in mature trees than in seedlings, whereas no such differences were found in Pinus densiflora and Fagus crenata. In broad-leaved trees, because the plant tissue radii lay within a narrow range, the FSA was affected mainly by the fungal sheath thickness. In conifers, however, the plant tissue radii varied widely among genera, so the FSA was affected by both the plant tissue radius and the fungal sheath thickness. Our findings suggest that the fungal content of ectomycorrhizal tips differs among tree species and fungal species, so that both parameters must be considered in studies of forest carbon cycling. The estimates revealed that data gathering in each type of forest leads to more accurate estimates of the biomass of fungi in ectomycorrhizal tips.

Seasonality of vertically partitioned soil CO2 production in temperate and tropical forest

Soil CO2 production seasonality at a number of depths was investigated in a temperate forest in Japan and in a tropical montane forest in Thailand. The CO2 production rates were evaluated by examining differences in the estimated soil CO2 flux at adjacent depths. The temperate forest had clear temperature seasonality and only slight rainfall seasonality, whereas the tropical montane forest showed clear rainfall seasonality and only slight temperature seasonality. In the temperate forest, the pattern of seasonal variation in soil respiration was similar at all depths, except the deepest (0.65 m–), and respiration was greater in summer and less in winter. The contribution of the shallowest depth (around 0.1 m) was more than 50% of total soil-surface CO2 flux all year round, and the annual mean contribution was about 75%. CO2 production mostly appeared to increase with temperature in shallower layers. In contrast, in the tropical forest, soil CO2 production seasonality appeared to differ with depth. The CO2 production rate in the shallowest layer was high during the rainy season and low during the dry season. Soil CO2 production at greater depths (0.4 and 0.5 m–) showed the opposite seasonality to that in the shallower layer (around 0.1 m). As a result, the contribution from the shallow depth was greatest in the tropical forest during the rainy season (more than 90%), whereas it decreased during the dry season (about 50%). CO2 production appeared to be controlled by soil water at all depths, and the different ranges of water saturation seemed to cause the difference in seasonality at each depth. Our results suggest the importance of considering the vertical distribution of soil processes, particularly in areas where soil water is a dominant controller of soil respiration.

Functional spatial scale of community composition change in response to windthrow disturbance in a deciduous temperate forest

Community dynamics in local habitats are affected by landscape characteristics such as the area and connectivity of surrounding habitats at a functional spatial scale where the community responds to landscape structure. However, the functional spatial scale at which community composition is affected by landscape structure has never been explored. We assessed the functional spatial scales of composition change in birds and in three types of arthropod communities (canopy, forest-floor and flying ones) with regard to landscape heterogeneity resulting from a large typhoon in a temperate forest of Japan. We examined the effects of tree-fall disturbance on the communities at various spatial scales, with special attention to compositional evenness. The spatial scale of the best-fitting model, which was selected from models fitted to the disturbance area at stepwise spatial scales, was interpreted as the community-specific functional spatial scale. The composition of all communities studied was all significantly dependent on gap area. The functional spatial scale was highest in birds (370 m in radius), intermediate in flying arthropods (90 m) and lowest in canopy and forest-floor arthropods (10 m). This result may reflect typical dispersal ability and the spatial range of resource use in the community. Compositional changes in each community were consistent with theory regarding traits and responses of component taxa, although the enhancement of evenness was observed only in the arthropod communities. These results imply that management and reserve selection based on functional spatial scales can be effective in the conservation of biodiversity and ecosystem services at the community level.

Scale‐dependent effects of windthrow disturbance on forest arthropod communities

AbstractThe effect of disturbance on local communities may operate within the context of the spatial landscape. We examined the scale‐dependent effects of windthrow disturbance caused by a large typhoon on three arthropod communities in a temperate forest of Japan. Canopy arthropods were collected by beating foliage, forest‐floor arthropods were collected by sweeping the vegetation, and flying arthropods were collected in Malaise traps. To assess the “functional spatial scale” at which arthropods responded to tree‐fall disturbance, the gap rate was quantified at different spatial scales by sequentially enlarging the radius of a circular landscape sector in 10‐m increments from 10 to 500 m. We then analyzed the responses of order richness and abundance to the gap rate for each arthropod community. The spatial scale of the significant best‐fitting model, which was selected from the models fitted to the gap rate at stepwise spatial scales, was regarded as the arthropod‐specific functional spatial scale. Arthropod order richness was not dependent on the gap rate. In contrast, arthropod order abundance depended significantly on the gap rate in many orders, but varied in the response direction and functional spatial scale. These order‐specific, scale‐dependent responses to tree‐fall gaps could complicate interactions among organisms, leading to complex community organization. An understanding of the spatial processes that link the use of space by organisms with the spatial scale at which ecological processes are experienced is required to elucidate the responses of populations, communities, and biotic interactions to disturbances in a spatial landscape context.

Host abundance of crane flies (Diptera: Limoniidae) and their role as phoronts of Acari (Arachnida) inhabiting fungal sporophores

AbstractWe examined host abundance of limoniid flies between Agaricales (gill mushrooms) and Aphyllophorales (non-gilled fungi) and the importance of these flies as phoronts of mites inhabiting these fungal orders. Fungal sporophores were collected around transects established in five different-aged (13 to more than 100 years) forest stands from spring to fall in temperate forests of Japan. Limoniid flies and mites were collected from sporophores during transect sampling and reared from sporophores in the laboratory. All 11 limoniid species reared from sporophores used Aphyllophorales and six of these limoniid species also used Agaricales as their hosts. The total number of limoniid flies reared from Aphyllophorales was approximately seven times that reared from Agaricales. Eight of 15 Aphyllophorales species yielded multiple limoniid species. We conclude that Aphyllophorales are more important as hosts for fungivorous limoniid flies than Agaricales. Even a single fungal species can support more than one limoniid or mite species. One or two limoniid species are phoronts for one to three mite species inhabiting sporophores of Agaricales and Aphyllophorales. These flies have an important role as phoronts for some mite genera inhabiting fungal sporophores.

Carbon isotope dynamics during leaf litter decomposition with reference to lignin fractions

AbstractWe studied the dynamics of the stable C isotope ratio (δ13C) of Swida controversa and Fagus crenata leaf litter during decomposition for 35 months with reference to the relative enrichment of the residue by lignin fraction‐derived C. The study was carried out on upper and lower parts of a forest slope in a cool temperate forest in Japan. The enrichment of lignin fraction‐C was associated with a decrease in the δ13C of S. controversa residue. The decrease in δ13C was greater at the lower than the upper site for S. controversa. In contrast, the relative increase in lignin fractions in F. crenata residue was not associated with the changes of δ13C. 13C nuclear magnetic resonance analysis, which revealed the relative decrease in alkyl‐C and O‐alkyl‐C and the relative increase in aromatic‐C and carbonyl‐C, provided further evidence for the contribution of the selective preservation of lignin of plant origin to the increase in the lignin fraction.

The Role of Deciduous Species in the Structural Development of a Restored Warm Temperate Forest in Japan

The Role of Deciduous Species in the Structural Development of a Restored Warm Temperate Forest in Japan

The role of deciduous species in the structural development of a restored warm temperate forest in Japan

The role of deciduous species in the structural development of a restored warm temperate forest in Japan