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Carbon pool densities and a first estimate of the total carbon pool in the Mongolian forest‐steppe 下载免费PDF全文
Choimaa Dulamsuren Michael Klinge Jan Degener Mookhor Khishigjargal Tselmeg Chenlemuge Banzragch Bat‐Enerel Yolk Yeruult Davaadorj Saindovdon Kherlenchimeg Ganbaatar Jamsran Tsogtbaatar Christoph Leuschner Markus Hauck 《Global Change Biology》2016,22(2):830-844
The boreal forest biome represents one of the most important terrestrial carbon stores, which gave reason to intensive research on carbon stock densities. However, such an analysis does not yet exist for the southernmost Eurosiberian boreal forests in Inner Asia. Most of these forests are located in the Mongolian forest‐steppe, which is largely dominated by Larix sibirica. We quantified the carbon stock density and total carbon pool of Mongolia's boreal forests and adjacent grasslands and draw conclusions on possible future change. Mean aboveground carbon stock density in the interior of L. sibirica forests was 66 Mg C ha?1, which is in the upper range of values reported from boreal forests and probably due to the comparably long growing season. The density of soil organic carbon (SOC, 108 Mg C ha?1) and total belowground carbon density (149 Mg C ha?1) are at the lower end of the range known from boreal forests, which might be the result of higher soil temperatures and a thinner permafrost layer than in the central and northern boreal forest belt. Land use effects are especially relevant at forest edges, where mean carbon stock density was 188 Mg C ha?1, compared with 215 Mg C ha?1 in the forest interior. Carbon stock density in grasslands was 144 Mg C ha?1. Analysis of satellite imagery of the highly fragmented forest area in the forest‐steppe zone showed that Mongolia's total boreal forest area is currently 73 818 km2, and 22% of this area refers to forest edges (defined as the first 30 m from the edge). The total forest carbon pool of Mongolia was estimated at ~ 1.5?1.7 Pg C, a value which is likely to decrease in future with increasing deforestation and fire frequency, and global warming. 相似文献
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Higher climate warming sensitivity of Siberian larch in small than large forest islands in the fragmented Mongolian forest steppe 下载免费PDF全文
Elmira Khansaritoreh Choimaa Dulamsuren Michael Klinge Tumurbaatar Ariunbaatar Banzragch Bat‐Enerel Ganbaatar Batsaikhan Kherlenchimeg Ganbaatar Davaadorj Saindovdon Yolk Yeruult Jamsran Tsogtbaatar Daramragchaa Tuya Christoph Leuschner Markus Hauck 《Global Change Biology》2017,23(9):3675-3689
Forest fragmentation has been found to affect biodiversity and ecosystem functioning in multiple ways. We asked whether forest size and isolation in fragmented woodlands influences the climate warming sensitivity of tree growth in the southern boreal forest of the Mongolian Larix sibirica forest steppe, a naturally fragmented woodland embedded in grassland, which is highly affected by warming, drought, and increasing anthropogenic forest destruction in recent time. We examined the influence of stand size and stand isolation on the growth performance of larch in forests of four different size classes located in a woodland‐dominated forest‐steppe area and small forest patches in a grassland‐dominated area. We found increasing climate sensitivity and decreasing first‐order autocorrelation of annual stemwood increment with decreasing stand size. Stemwood increment increased with previous year's June and August precipitation in the three smallest forest size classes, but not in the largest forests. In the grassland‐dominated area, the tree growth dependence on summer rainfall was highest. Missing ring frequency has strongly increased since the 1970s in small, but not in large forests. In the grassland‐dominated area, the increase was much greater than in the forest‐dominated landscape. Forest regeneration decreased with decreasing stand size and was scarce or absent in the smallest forests. Our results suggest that the larch trees in small and isolated forest patches are far more susceptible to climate warming than in large continuous forests pointing to a grim future for the forests in this strongly warming region of the boreal forest that is also under high land use pressure. 相似文献
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Davaadorj P Tokuyama R Ide S Tadokoro S Kudoh K Satomura K 《Histochemistry and cell biology》2010,134(6):603-614
Maspin is a 42 kDa serine protease inhibitor that possesses tumor suppressive and anti-angiogenic activities. Despite of a
huge amount of data concerning the expression pattern of maspin in various tissues and its relevance to the biological properties
of a variety of human cancer cells, little is known on the maspin expression in skeletal and tooth tissues. Recently, we reported
that maspin may play an important role in extracellular matrix formation in bone by enhancing the accumulation of latent TGF-β
in the extracellular matrix. This study was performed to elucidate the possible role of maspin in tooth development. First,
an immunohistochemical analysis for human tooth germs at the late bell stage showed the expression of maspin by active ameloblasts
and odontoblasts that were forming enamel and dentin, respectively. During rat tooth development, maspin expression was observed
for the first time in inner and outer enamel epithelial cells and dental papilla cells at early bell stage. The neutralizing
anti-maspin antibody inhibited the proper dental tissue formation in organ cultures of mandibular first molars obtained from
21-day-old rat embryos. In addition, the proliferation of HAT-7 cells, a rat odontogenic epithelial cell line, and human dental
papilla cells were suppressed in a dose-dependent manner with anti-maspin antibody. Moreover, RT-PCR analysis showed that
the expression of mRNA for tooth-related genes including dentin matrix protein 1, dentin sialophosphoprotein and osteopontin
in human dental papilla cells was inhibited when treated with anti-maspin antibody. These findings suggest that maspin expressed
in ameloblasts and odontoblasts plays an important physiological role in tooth development through the regulation of matrix
formation in dental tissues. 相似文献
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Ide S Tokuyama R Davaadorj P Shimozuma M Kumasaka S Tatehara S Satomura K 《Histochemistry and cell biology》2011,135(3):281-292
Leptin, a 16 kDa non-glycolated polypeptide of 146 amino acids produced by the ob gene, has a variety of physiological roles not only in lipid metabolism, hematopoiesis, thermogenesis and ovarian function,
but also in angiogenesis. This study focuses to investigate the possibility that leptin, as an angiogenic factor, may regulate
the angiogenesis during tooth development. We firstly studied the expression of leptin and vascular endothelial growth factor
(VEGF) during tooth development immunohistochemically. This investigation revealed that leptin is expressed in ameloblasts,
odontoblasts, dental papilla cells and stratum intermedium cells. This expression pattern was similar to that of VEGF, one
of the most potent angiogenic factors. Interestingly, more leptin-positive cells were observed in the upper third portion
of dental papilla, which is closest to odontoblastic layer, compared to middle and lower thirds. Moreover, in the dental papilla,
more CD31 and/or CD34-positive vascular endothelial cells were observed in the vicinity of ameloblasts and odontoblasts expressing
leptin and VEGF. These findings strongly suggest that ameloblasts, odontoblasts and dental papilla cells induce the angiogenesis
in tooth germs by secretion of leptin as well as VEGF. 相似文献
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Fujio Hyodo Junko Nishikawa Ayato Kohzu Noboru Fujita Izuru Saizen Jamsran Tsogtbaatar Choijilsuren Javzan Mangaa Enkhtuya Davaadorj Gantomor Narantsetsegiin Amartuvshin Reiichiro Ishii Eitaro Wada 《Limnology》2012,13(1):155-161
The stable nitrogen (N) isotope ratio (??15N) has been used to examine the anthropogenic N input (i.e., septic water, wastewater, and manure) to aquatic ecosystems, because anthropogenic N generally has a ??15N signature distinct from that found in nature. Aquatic organisms and the derived organic matter such as sediments are reported to become increasingly enriched in 15N as the human population density increases in watersheds. However, little is known about the relationship in steppe ecosystems, where the livestock population is greater than that of humans. Here, we conducted a preliminary study in the Selenga river mainstream watershed in Mongolia, which covers an area of approximately 300,000?km2. A multiple regression analysis revealed that the ??15N of the riverine sediment was significantly affected by the human population density and more significantly by livestock population density. The population density, including both humans and livestock, significantly influenced ??15N of the macrophytic Potamogeton spp. The results showed that ??15N of riverine organic matter can be an indicator of the human and livestock population density, which is likely associated with the status of N cycles in livestock-dominated watersheds. 相似文献
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