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Kanehiro Kitayama - One of the best experts on this subject based on the ideXlab platform.
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temperature is a dominant driver of distinct annual seasonality of leaf litter production of equatorial tropical Rain Forests
bioRxiv, 2020Co-Authors: Kanehiro Kitayama, Masayuki Ushio, Shinichiro AibaAbstract:ABSTRACT Intra-annual periodicity of canopy photosynthetic activity and leaf development has been documented in seasonal and weakly-seasonal tropical Forests in the Amazon and elsewhere. However, vegetative periodicity such as leaf flush and fall in apparently “aseasonal” equatorial tropical Forests has not been well documented. Moreover, causal drivers of the vegetative periodicity in those Forests have not been identified largely because of the difficulty in performing manipulative experiments targeting whole forest ecosystem dynamics. Here we show a distinct annual seasonality in canopy dynamics using a Fourier analysis with a statistical significance test on the long-term, fortnightly monitored dataset of leaf litterfall in nine evergreen tropical Rain Forests on Mount Kinabalu, Borneo. Statistically significant annual periodicity occurs across altitudes and soil types in all years irrespective of the year-to-year climatic variability, suggesting that fluctuations in regional climate rather than local micro-climatic, edaphic and/or biotic conditions cause the precise 1-year periodicity. We examine climatic factors that have causative effects on the distinct 1-year periodicity using the spectrum convergent cross mapping that we developed in the present study to distinguish causal relationships from seasonality-driven synchronization. According to the analysis, we find that mean daily air temperature is most strongly, causatively related to the 1-year periodicity of leaf litterfall. However, knowledge on ecophysiolocial and molecular mechanisms underlying temperature-control of tropical tree growth is limited and further studies are required to understand the detailed mechanisms. (Synthesis) We suggest that intra-annual temperature changes in association with the movement of the intertropical convergence zone cause the distinct annual vegetative periodicity. Because vegetative periodicity can be transmitted to the dynamics of higher trophic levels through a trophic cascade, interactions between vegetative periodicity and daily air temperature, not Rainfall, would more strongly cause changes in the dynamics of equatorial tropical Rain Forests. Our results show that clear vegetative periodicity (i.e., annual seasonality) can be found in equatorial tropical Rain Forests under diverse local environments, and that air temperature is a more important factor than the other climate variables in the climate-forest ecosystem interactions.
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effects of nitrogen and phosphorus fertilization on the activities of four different classes of fine root and soil phosphatases in bornean tropical Rain Forests
Plant and Soil, 2017Co-Authors: Daiki Yokoyama, Nobuo Imai, Kanehiro KitayamaAbstract:Soil hydrolysable P can be a main P source for biota in P-limited tropical Rain Forests. Soil hydrolysable P occurs in various chemical fractions, including, monoester P, diester P, pyrophosphate and phytate, which need enzymatic hydrolysis into orthophosphate before their assimilation into biota. We examined whether P-limited plants and microbes preferentially hydrolyzed specific fraction of soil hydrolysable P and whether those in different successional stages had different abilities to hydrolyze various soil hydrolysable P. We measured four classes of phosphatase (phosphomonoesterase, PME; phosphodiesterase, PDE; pyrophosphatase, PyP; and phytase, PhT) activities for fine-roots and soils in nitrogen (N) and P fertilized primary and secondary tropical Rain Forests in Sabah, Malaysia. P fertilization reduced PME, PyP and PhT activities for fine-roots and PME and PyP activities for soils. Fine-roots in primary Forests had higher PME and PyP activities whereas those in secondary Forests had higher PhT activities. We suggest that P-limited trees and microbes depend more on hydrolysable P degraded by one step of enzymatic reaction (monoester P, pyrophosphate, and phytate) as a P source. We also suggest that trees have different soil-organic-P acquisition strategies in association with their life history strategies.
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nutrient allocation among plant organs across 13 tree species in three bornean Rain Forests with contrasting nutrient availabilities
Journal of Plant Research, 2016Co-Authors: Ryota Aoyagi, Kanehiro KitayamaAbstract:Allocation of nitrogen (N) and phosphorus (P) among plant organs is an important factor regulating growth rate, which is a key ecological process associated with plant life-history strategies. However, few studies have explored how N and P investment in photosynthetic (leaves) and non-photosynthetic (stems and roots) organs changes in relation to depletion of each element. We investigated nutrient concentrations of plant organs in relation to whole-plant nutrient concentration (total nutrient weight per total biomass) as an index of nutrient status of each individual using the saplings of the 13 species in three tropical Rain Forests with contrasting N and P availabilities (tropical evergreen Forests and tropical heath Forests). We found a steeper decrease in foliar N concentration than foliar P concentration with decreasing whole-plant nutrient concentration. Moreover, the steeper decrease in foliar N concentration was associated with relatively stable N concentration in stems, and vice versa for P. We suggest that the depletion of N is associated with a rapid dilution of foliar N because the cell walls in non-photosynthetic organs function as an N sink. On the other hand, these species can maintain foliar P concentration by decreasing stem P concentrations despites the depletion of P. Our results emphasize the significance of non-photosynthetic organs as an N sink for understanding the variation of foliar nutrient concentrations for the tree species in the three Bornean Rain Forests with different N and P availabilities.
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structure floristics and diversity of tropical montane Rain Forests over ultramafic soils on mount kinabalu borneo compared with those on non ultramafic soils
Australian Journal of Botany, 2015Co-Authors: Shinichiro Aiba, Kanehiro Kitayama, Yoshimi Sawada, Masaaki Takyu, Tatsuyuki Seino, Rimi RepinAbstract:We describe here the structure, floristics and diversity of tropical montane Rain Forests over ultramafic soils on Mount Kinabalu, Borneo, and compared them with those on non-ultramafic soils. We used 14 sample plots from 1580 to 3080 m elevation, six on ultramafic soils and eight on non-ultramafic soils, and identified all trees ≥4.8 cm diameter. The plot area ranged from 0.1 to 1 ha, the majority (nine plots) being 0.25 ha. Forests on ultramafic soils showed more stunted structure, especially at higher altitudes, than those on non-ultramafic soils and on ridges than on slopes. Species of Coniferae (Araucariaceae and Podocarpaceae) and Myrtaceae strongly dominated on ultramafic soils occupying 61–96% of basal area in each plot, compared with 22–63% on non-ultramafic soils. Among 287 species found in the 14 plots, only nine species (including four species endemic to Mount Kinabalu) were strictly restricted to ultramafic soils. Nonmetric multidimensional scaling demonstrated that elevational change in species composition was accelerated on ultramafic soils and on ridges. Tree species diversity was generally lower on ultramafic soils than on non-ultramafic soils at the comparative altitudes. Multiple regression analysis suggested that soil nutrients (phosphorus and nitrogen) could be the cause of vegetation differentiation between ultramafic and non-ultramafic soils, although the data on soil metals are lacking. Comparison of our results with those from other mountains with ultramafic soils in South-east Asia demonstrated the uniqueness of the montane Rain Forests over ultramafic soils on Mount Kinabalu.
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The activities of soil and root acid phosphatase in the nine tropical Rain Forests that differ in phosphorus availability on Mount Kinabalu, Borneo
Plant and Soil, 2013Co-Authors: Kanehiro KitayamaAbstract:Background and aims Tropical Rain Forests on deeply weathered soils are increasingly thought to be limited by phosphorus (P), where plants and associated organisms would demonstrate adaptations to efficiently recycle P using acid phosphatase from organic matter. The activities of soil and root acid phosphatase were investigated in nine tropical Rain Forests that demonstrated a 20-fold difference in the soil organic P pool on Mt. Kinabalu, Borneo. Methods Acid phosphatase activity was measured at pH6.0 using p-nitrophenyl phosphate as substrate. Results The specific phosphatase activity of tree roots on a soil-surface-area basis was significantly positively related with P-use efficiency of above-ground productivity, suggesting a physiological linkage between above and below-ground systems in the adaptation to P deficiency. The phosphatase activities of soils and roots were significantly negatively correlated with the pool size of soil organic P fractions, suggesting that demand for P determines phosphatase activities. Conclusions It is suggested that tree roots and soil microbes develop more active phosphatases in response to the chronic shortage of soil P, which forms the basis for an important functional role for the efficient acquisition of P from soil organic matter.
David M. J. S. Bowman - One of the best experts on this subject based on the ideXlab platform.
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Tropical Rain Forests
Progress in Physical Geography, 1998Co-Authors: David M. J. S. BowmanAbstract:Concern about the future of tropical Rain Forests has largely focused on threats to the survival of the extraordinary biological diversity that characterizes these ecosystems. Another perspective emphasizes the role that tropical Rain Forests play in the global carbon cycle. Despite covering only about 8% of the land surface, tropical Rain Forests are thought to contain about 40% of the terrestrial biomass and account for over 50% of the annual net primary productivity of the biosphere (Williams et al., 1998). Furthermore, recent evidence suggests that unlogged tropical Rain Forests act as a sink of anthropogenic carbon emissions (Grace et al., 1995). Conversely, the destruction of Rain Forests by land clearance and forest fires is a significant source of CO2, a point dramatically highlighted by the recent massive fires that have occurred in tropical Rain Forests worldwide (Malingreau et al., 1985; Brown, 1998). The purpose of this review is to report current research concerning the factors that influence carbon dynamics in tropical Rain Forests.
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Tropical Rain Forests
Progress in Physical Geography, 1998Co-Authors: David M. J. S. BowmanAbstract:Ten years ago Raven (1988) wrote an article entitled `Tropical floristics tomorrow\u27 in which he argued that there was an urgent need to undertake inventories of tropical plant species diversity because of the rapid rate of tropical Rain-forest destruction. Therefore it is timely to report on the progress in describing and explaining variation of biodiversity in tropical Rain Forests. I base this review on a search of the 1997 editions of Ecology Abstracts, Ecological Abstracts and Forestry Abstracts
John A. Silander - One of the best experts on this subject based on the ideXlab platform.
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Do Tropical Storm Regimes Influence the Structure of Tropical Lowland Rain Forests
Biotropica, 2003Co-Authors: Roland C. De Gouvenain, John A. SilanderAbstract:It has been suggested that the average canopy height of Madagascar's lowland Rain Forests is shorter and the average tree density is greater than in other tropical lowland Rain Forests of the world. The cause was hypothesized to be frequent cyclone disturbances. We compared the structure of the lowland Rain Forests in Madagascar to the structure described in published accounts of other tropical lowland Rain Forests. We found that the eastern coastal lowland Forests of Madagascar have short canopy heights relative to that of many other lowland tropical Rain Forests, and that these Malagasy Forests also have relatively high tree densities. On a worldwide basis, there is a significant correlation between short forest canopies and occurrence of tropical cyclones. The association between high tree density and occurrence of tropical cyclones is valid for Africa, but the pattern does not hold up globally.
Hua Zhu - One of the best experts on this subject based on the ideXlab platform.
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Ecological and biogeographical studies on the tropical Rain forest of south Yunnan, SW China with a special reference to its relation with Rain Forests of tropical Asia
Journal of Biogeography, 1997Co-Authors: Hua ZhuAbstract:Ecological and biogeographic analyses of the tropical Rain forest in south Yunnan were made using data from seventeen sample plots and floristic inventories of about 1000 species of seed plants. The Rain forest is shown to be a type of true tropical Rain forest because it has almost the same profile, physiognomic characteristics, species richness per unit area, numbers of individuals in each tree species and diameter classes of trees as classic lowland tropical Rain Forests. As the area is at the northern margin of monsoonal tropics, the Rain forest differs from equatorial lowland Rain Forests in having some deciduous trees in the canopy layer, fewer megaphanaerophytes and epiphytes but more species of lianas as well as more species of microphylls. In its floristic composition, about 80% of total families, 94% of total genera and more than 90% of total species are tropical, of which about 38% of genera and 74% of species are tropical Asian. Furthermore, the Rain forest has not only almost the same families and genera, but also the same families rank in the top ten both in species richness and in dominance of stems, as lowland Forests in southeast Asia. It is indisputable that the flora of the Rain forest is part of the tropical Asian flora. However, most of the tropical families and genera have their northern limits in south Yunnan and most have their centre of species diversity in Malesia. More strictly tropical families and genera have relatively lower species richness and importance compared with lowland Rain Forests in tropical southeast Asia. Thus, the flora also shows characteristics of being at the margin of the tropics. Based mainly on physiognomy and floristic composition the tropical Rain forest of Yunnan is classified into two types, i.e. seasonal Rain forest and wet seasonal Rain forest, the latter is further divided into two subtypes, i.e. mixed Rain forest and dipterocarp Rain forest. From analysis of geographic elements it is also shown that the tropical Rain forest of Yunnan occurs at a geographical nexus with its flora coming mainly from four sources, i.e. Malesia, south Himalayas, Indochina and China.
Hanna Tuomisto - One of the best experts on this subject based on the ideXlab platform.
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are floristic and edaphic patterns in amazonian Rain Forests congruent for trees pteridophytes and melastomataceae
Journal of Tropical Ecology, 2007Co-Authors: Kalle Ruokolainen, Manuel J. Macía, Hanna Tuomisto, Mark A Higgins, Markku YlihallaAbstract:Studies in western Amazonian Forests have found that similarities in soil cation concentration and texture explain floristic similarities between sites, when these are measured using trees, pteridophytes or Melastomataceae. However, it is not known to what extent the three plant groups react to the same soil characteristics, because tree studies have almost always been conducted in different areas than studies on the understorey plant groups. We made inventories in 23 sites representing non-inundated Rain Forests on clayey to loamy soil in three regions of western Amazonia. Significant Mantel correlations between the floristic patterns of trees and pteridophytes were found in all three regions when floristic differences were measured with species presence-absence data. When species abundance data were used, and when the floristic patterns of trees and Melastomataceae were compared, significant correlations werefoundinoneortworegions.Mantelcorrelationsbetweenplantgroupswerehighestinthetworegionswherethe observed variation in soil characteristics was largest. In all regions, the same soil variables emerged with significant Mantelcorrelationswithtrees,pteridophytesandMelastomataceae.Soilcalciumandmagnesiumweremostfrequently retained in the models of multiple regression on distance matrices. On average, soil differences explained 50% of the variation in floristic differences (range =14-84%), and geographical distances explained 16% (range =0-64%). Our results demonstrate that beta diversities of the three plant groups are highly correlated, and that much of this congruence is explained by similar reactions to soil variation. These results support the idea that pteridophytes, and to a lesser degree Melastomataceae, can be used as indicators of generalfloristic and edaphic patterns in Amazonian Rain Forests. Since understorey plants are much quicker to inventory than trees, this would make it possible to recognize and map floristic patterns over huge areas of lowland Amazonia within a reasonable time.
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mapping gradual landscape scale floristic changes in amazonian primary Rain Forests by combining ordination and remote sensing
Global Ecology and Biogeography, 2005Co-Authors: Sirpa Thessler, Kalle Ruokolainen, Hanna Tuomisto, Erkki TomppoAbstract:Aim We present a new method to economically map gradual changes in plant species composition in lowland Rain Forests using field data and satellite images. Such a method will be a useful tool in planning the sustainable use and conservation of Amazonian Rain Forests. Location The study covered an area of c. 700 km2 of primary Rain forest in Amazonian Ecuador. Methods We field inventoried the species composition of pteridophytes and Melastomataceae in 340 inventory plots (5 m × 50 m), described the prevailing topography and analysed soil cation concentration and texture. We used non-metric multidimensional scaling (NMDS) to summarize the floristic variation among the inventory plots in three ordination dimensions. The scores of the three ordination axes were predicted to non-visited places using a Landsat TM (thematic mapper) satellite image and the k nearest neighbours (knn) estimation method. To avoid extrapolation, we excluded from the analysis those pixel windows whose spectral values were not represented in the areas covered by field sampling. The accuracy of the predictions was evaluated by cross-validation and by comparing the predictions based on spectrally nearest neighbours to the predictions based on random neighbours. Results The floristic gradients presented by NMDS ordination were interpretable in terms of topography, dRainage and soil cation content. Thirteen percent of the cloud-free pixels were excluded from the knn analysis to avoid extrapolation. The estimates of the floristic ordination scores based on spectrally nearest neighbours were always more accurate than estimates based on random neighbours. Main conclusions The presented method needs a relatively small input of work and resources, is mechanistic and produces maps that give relevant information on floristic variation over forest areas that are traditionally considered essentially homogeneous. Therefore, the method appears to have a great potential for use in mapping large areas of Amazonian Rain Forests.
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influence of edaphic specialization on pteridophyte distribution in neotropical Rain Forests
Journal of Biogeography, 1996Co-Authors: Hanna Tuomisto, Axel Dalberg PoulsenAbstract:The abundance of terrestrial pteridophytes was studied in eight sites in Western Amazonia, all representing lowland tropical Rain forest in non-inundated terRain (tierra firme). In each site, a sample plot ranging from 0.25 ha to 1.00 ha in area was inventoried and all terrestrial pteridophytes were recorded. In total, 27,000 individuals representing sixty-four species were encountered, with each plot having between fourteen and thirty-three species. The plots represented a gradient from nutrient-poor sandy soils to relatively fertile clay soils, and it was found that their floristic compositions clearly correlated with the differences in the soils. Two-thirds of the species were restricted either to poor, intermediate or rich soils, while less than a tenth were found growing on all soil types. Analyses of species lists from another twenty neotropical localities supported the result that some pteridophyte species associate, whereas other species are never found growing together. The floristic similarities among sites showed no relationship to the geographical distances between them, but rather reflected similarities in soils. It is concluded that pteridophytes are good indicators of such ecological conditions, and that when interpreting biogeographical patterns in the neotropical Rain Forests, it is important to take into account the distribution of edaphically different habitats.