Buho Hoshino

Invasion of dwarf bamboo into alpine snow-meadows in northern Japan: pattern of expansion and impact on species diversity

Recently, a dwarf bamboo species,Sasa kurilensis; Poaceae, has invaded into alpine snow-meadows in the wilderness area of the Taisetsu Mountains, northern Japan. This dwarf bamboo species has a wide distribution range from lowland to alpine sites of snowy regions. Because of the formation of dense evergreen culms and an extensive rhizome system, other plants are excluded following invasion by this dwarf bamboo, resulting in low species diversity. Dwarf bamboo originally inhabited the leeward slopes of alpine dwarf pine (Pinus pumila) clumps in alpine regions. During the last 32 years, however, dwarf bamboo has expanded its distribution area by up to 47% toward snow-meadows, especially on southeastern facing slopes. This rapid change may be related to the decrease in soil moisture and expansion of the annual growing period caused by the recent acceleration of snowmelt time. A multiyear census revealed that the density of bamboo culms increased 30–150% during 2 years, and the annual expansion of bamboo rhizomes was 39 cm on average. In addition to the expansion of bamboo clumps by vegetative growth, the possibility of migration by seed dispersal was also suggested by a genet analysis. With the increase in culm density, the species richness of snow-meadow vegetation decreased to less than one-quarter of the original level due to intense shading by dwarf bamboo. The rapid vegetation change in these almost pristine alpine environments isolated from the human activity implies that global climate change already influences the alpine ecosystem.

Remote sensing methods for the evaluation of the mesquite tree (Prosopis juliflora) environmental adaptation to semi-arid Africa

In this study a remote sensing approach for the mesquite tree (Prosopis juliflora) control is proposed. The mesquite tree is well known for its high adaptability to arid and semi-arid conditions and characterized by very high water use efficiency. Introduction of the mesquite has caused several environmental problems in Sudan. In this study, to monitor mesquite water use efficiency the concept of a Normalized Difference Infrared Index (NDII), which is defined as the ratio of actual to foliar water content, have been applied and compared with the ground measurements of stomatal conductance (mmol. m-2. s-1), field spectral, volumetric soil water content. As results, on the base of the PALSAR L-band microwave polarimetric backscatter coefficient, the soil moisture (in bare soil area) and surface roughness (in dense forest covered area) could be estimated with a good accuracy for bare-soil surfaces.

The impact of land cover change on patterns of zoogeomorphological influence: Case study of zoogeomorphic activity of Microtus brandti and its role in degradation of Mongolian steppe

Earths surface building and changing by endogenetic and exogenetic processes. Endogenous processes are large-scale landform building and transforming processes. However, The exogenetic processes are the processes that shape the land by forces coming on or above the Earths surface (exogenetic forces), such as zoogeomorphic activity. Ecosystems in the Central Asian Plateau, which includes the Mongolian Plateau, are becoming increasingly sensitive to human interventions, leading to deterioration of already fragile ecosystems. Grassland ecosystems supply almost all of the forage needed for livestock production in the Mongolian Plateau, and support the livelihood of the regions herders and their primarily nomadic way of life. However, the grassland ecosystems are distributed over a vast region that ranges between forest and desert ecosystems, and negligent human activities have caused serious environmental consequences for human society. The degraded grassland is habitat of Brandts vole (Microtus brandti). Does Brandts vole make damage to the environment or it provides management? Therefore we analysing NDVI, soil temperature and soil hardness measurements at the Brandts vole colony, to examine changes of land surface characteristics by activity of Brandts vole. As conclusion, we suppose that Brandts vole is might indicate the degradation of pasture and play important role in ecosystem recovery.

Remote sensing methodology for detection of environmental regime shifts in semi-arid region

Precipitation is one of the most important factors for growth of plants especially in arid and semi-arid regions. In this study, we show that vegetation in the arid and semi-arid Gobi region is sensitive to the dynamics of precipitation. Using satellite imagery we analyzed the space-time features of seasonal vegetation evolution and anomaly patterns from 1985 to 2013. Cross correlation analysis was used to evaluate the response of vegetation to precipitation. We found that vegetation in low precipitation areas such as around Gansu in China was degraded than that in high precipitation areas.

Problems in the Protection of Reintroduced Przewalski's Horses (Equus ferus przewalskii) Caused by Piroplasmosis

Abstract The objectives of our research on equine piroplasmosis were to clarify the prevalence of the piroplasms Babesia caballi and Theileria equi among reintroduced Przewalskis horses (takhi, Equus ferus przewalskii) in comparison with horses (Equus caballus) of nomads from around Hustai National Park in Mongolia and to determine the mortality among takhi during 2012 to 2015. The prevalence of T. equi was high in 2014 at 80% among nomadic horses and 84% among takhi. We found no evidence of B. caballi infection among takhi. A homology comparison of the 18S rRNA base sequence of T. equi showed the same sequence in both domestic horses and takhi. According to the national park records, piroplasmosis is a cause of high mortality in young takhi (19%). The results suggested that takhi were infected with T. equi in this park, and the infection is an important issue when reintroducing the takhi into the wild and increasing the numbers of the animals in nature. Continuous monitoring and vector control were noted as important issues in future conservation programs.

Evaluation of the Effect of a Rain Pulse on the Initial Growth of Prosopis Seedlings

Prosopis juliflora is a useful “multi-purpose” tree, but it invades rapidly in arid and semi-arid environments, causing livelihood degradation of local communities. A rain pulse under drought conditions has been reported to be an important factor to promote plant invasion. The purpose of this research was to evaluate the effect of a rain pulse on the invading process of Prosopis juliflora and to propose a feasible plan to control the expansion of this species in Sudan. First, seed germination was examined under eight irrigation conditions, corresponding to 4–32 mm of rainfall. Most seeds imbibed in all the irrigation conditions, about half or more of the imbibed seeds germinated in 12 mm or more of irrigation. Twenty mm or more of irrigation induced seed emergence. Second, initial growth of germinated seeds was examined under ten irrigation conditions (1–32 mm rainfall) over 54 hours or 138 hours of cultivation. Radicle elongated most vigorously in 24 mm irrigation, and extended over 20 cm in length. Allocation to radicle was dominant, and its elongation was promoted in higher soil moisture condition. Based on these results, we propose that seedlings of P. juliflora should be eradicated within a few weeks after a single large rainfall, which might be convenient and effective to control additional expansion of this species in Sudan.

Change detection method for pasture degradation using RGB color composite image of multitemporal Landsat TM - A case study of the Inner Mongolian settlement region

This study was performed at Abag banner in Inner Mongolia. Two Landsat TM data were acquired separately in 1989 and 2011 over the study area. Soil Adjusted Vegetation Index (SAVI) were derived from reflectance spectra, and applied to compare the green vegetation cover. The change detection result show that there is a large change in land cover, and most vegetation decreasing area was located overgrazing pasture area. During past 22-years, about 36.3% of the area was decreased in vegetation. Our result also indicated that vegetation cover change can be observed using satellite data. And the analysis of vegetation trends in land cover change using remote sensing change detection is a useful method to document the human impacts on ecosystems.

Estimated soil moisture in vegetated area using multitemporal multipolarization data

Alpine ecosystem is the most sensitive terrestrial ecosystem to global climate change. Recently, a dwarf bamboo species, Sasa kurilensis, (Poaceae), has invaded into alpine snow-meadows in the wilderness area of the Taisetsu Mountains, northern Japan. The spatial distribution and seasonal changes in soil moistures are key parameter in numerous environmental studies at both regional and global scales including hydrological, ecological, climatic and agricultural fields. However, the natural variability and complexity of vegetation canopy and surface roughness significantly affect the sensitivity of backscatter from soil. This study indicates a new method to estimate surface soil moisture in high density vegetated area in the Taisetsu Mountains with an L-band dual-polarization (HH and HV) radiometer measurements. For dense vegetated surfaces, we used the multitemporal and multipolarization backscatter coefficient data and the subtraction methods to provide the estimation of vegetation effects. After the soil moisture corrected based on vegetation phenology, the surface soil moisture can be inferred by the estimated surface backscatter signals.

Investigation on the water stress in alpine vegetation using Hyperspectral sensors

The effect of global warming may be seen even on the top of the Mt. Daisetsuzan National Park (DNP) in Japans northernmost island of Hokkaido where communities of alpine plants having been greatly suffered from the expansion of alien species. Alpine of the Mt. Daisetsu is in protected zone of the DNP and has no direct human influence. So far, this happening might indicate the negative effects of global scale climate changes in high mountainous ecosystem. Seriousness of that phenomenon is that it is completely changing the local vegetation. Due to the global warming, increased temperature causes rapid melting of the snow coverage at DNP and soil is quickly losing its moisture. In this study, alpine meadow vegetation in DNP was photographed with aid of the hyper-spectral sensors mounted on the airplane. Simultaneously, ground observations were also made. Hyperspectral sensors are having 60 bands with wavelength from 400 to 1000 nm, and resolution of 10 nm. Ground observations were made using the Field Spec devices for spectral measurement, GPS for mapping. Plant species, coverage, and soil moisture were investigated.

Estimates of critical ground surface condition for Asian dust storm outbreak in Gobi desert region based on remotely sensed data

The Inland Asian dry land, such as Gobi and desert of Mongolian Plateau is the most important dust source region in the world. However, in recent years the dust storms were found to have been outbreak from the pastureland around the dry lakes, dry river channels and degraded pasturelands. Surrounding of dry lakes, dry river channels and degraded pastures are the main new sources of Asian Dust Storms (ADS). In this study, we measure of the Critical Ground Surface Condition (CGSC) (such as vegetation index (NDVI), soil moisture index, terrain roughness index, and soil particles) in ASD source region, with the influence on dust storm outbreak based on satellite data to evaluate the mechanism of ADS outbreak.