Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production i...Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production in three forests in Jeju Island differentiated by forest composition and precipitation: Cheongsu(Quercus glauca as the dominant species;low precipitation), Seonheulb(Q. glauca as the dominant species;high precipitation), and Seonheulm(Q. glauca and Pinus thunbergii as the dominant species;high precipitation). Litterfall was collected monthly from April to December 2015 and divided into leaf litter, twig, bark, seeds, and unidentified materials.Seasonal patterns of litterfall production varied across stands according to their species composition. However,the amount of leaf litterfall and total litterfall were comparable among stands, ranging from 362 to 375 g m-2 for leaf litter and 524 g m-2 to 580 g m-2 for total litterfall.Oak leaf litter in May was the highest in all stands, while needle litter was the highest in December in Seonheulm.High twig litterfall in July may be attributable to high rainfall with strong winds and storms during the rainy season. Although forest type and climate factor had no influence on litterfall amounts in this study, the pattern of litterfall production was species dependent, suggesting diverse effects on carbon and nutrient cycling in these forests.展开更多
Although information regarding the initiation processes of debris flows is important for the development of mitigation measures,field data regarding these processes are scarce.We conducted field observations of debris...Although information regarding the initiation processes of debris flows is important for the development of mitigation measures,field data regarding these processes are scarce.We conducted field observations of debris-flow initiation processes in the upper Ichinosawa catchment of the Ohya landslide,central Japan.On 19 June 2012,our videocamera monitoring systems recorded the moment of debris-flow initiation on channel deposits(nine surges) and talus slopes(eight surges).The initiation mechanisms of these surges were classified into three types by analyzing the video images: erosion by the surface flow,movement of deposits as a mass,and upward development of the fluid area.The first type was associated with the progress of surface flow from the upper stream on unsaturated channel deposits.The second type was likely caused by an increase in the pore water pressure associated with the rising in the groundwater level in channel deposits;a continuous water supply from the upper stream by the surface flow might have induced this saturation.The third type was associated with changes in the downstream topography caused by erosion.The flow velocity of most surges was less than 3 m s^(-1) and they usually stopped within 100 m from the initiation point.Surges with abundant pore fluid had a higher flow velocity(about 3- 5 m s^(-1)) and could travel for alonger duration.Our observations indicate that the surface flow plays an important role in the initiation of debris flows on channel deposits and talus slopes.展开更多
The management of forest corridors and related ecology is one of the effective strategies to minimize the adverse effects of forest degradation. It controls the connectivity of inhabitant species and the connection of...The management of forest corridors and related ecology is one of the effective strategies to minimize the adverse effects of forest degradation. It controls the connectivity of inhabitant species and the connection of the isolated patches. This study analyzed spatial and temporal forest physical degradation based on forest cover change and forest fragmentation in the Gishwati-Mukura biological corridor from 1990-2019. Remotely sensed datasets, Geographical Information System (GIS) and FRAGSTATS software were used to analyze the spatial and temporal physical degradation and changes in forest cover. The results indicated that the Gishwati-Mukura corridor experienced massive deforestation where approximately 7617.1 ha (64.22%) of forest cover was completely cleared out, which implies an annual forest loss of 262.6 ha·year<sup>-</sup><sup>1</sup> (2.21%) during 1990-2019. The forest cover transitions patterns and geostatistical analysis indicated that extensive deforestation was associated with intensive agriculture. The results demonstrated that agriculture has dramatically increased from 29.46% in 1990 to 57.22% in 2019, with an annual increase of 1.97%. Since Gishwati-Mukura has changed to National Park (NP), it lacks diversified scientific studies addressing the analysis of the remote and spatial patterns to investigate its physical degradation and landscape dynamics. This research study will serve as remote forest analysis gap-filling and as the cornerstone of numerous other research that will contribute to the improvement of the connectivity assessments along the Gishwati-Mukura corridor and other related ecosystems.展开更多
Mammal distribution is shaped by different ecological and anthropogenic factors,and the pattern varies depending on their sensitivity thresholds,food and habitat preferences,ecological roles,and physical traits.The pr...Mammal distribution is shaped by different ecological and anthropogenic factors,and the pattern varies depending on their sensitivity thresholds,food and habitat preferences,ecological roles,and physical traits.The present study investigated the influence of ecological and anthropogenic factors on the distribution of mammal species communities across different trophic levels and body sizes in Myanmar's Htamanthi Wildlife Sanctuary(HWS).The values of mammal characteristics,ecological,and anthropogenic factors were analyzed in ArcMap software.Most of the large and small sized mammals,whose distribution decreases with elevation,were observed near the main streams.Across mammal tropic levels,the omnivores and herbivores were mostly observed farther from gold mining sites.In terms of forage plant effect on mammal community,floral forage plants and the presence of climber negatively affected mammal species across different trophic levels.Moreover,presence of resin trees also has a substantial impact on the distribution of medium-large animals and omnivorous mammals as trophic niche factors.Overall,our findings highlight the crucial role that ecological and anthropogenic factors play in shaping mammal distribution in the HWS.This underscores the importance of simultaneously conserving both habitat and mammal diversity in HWS,especially in the face of a changing climate and environment.展开更多
Background:In reclaimed land,the growth environment for plants may be unfavorable and the initial establishment and growth of seedlings could be limited because of low nutrient and water availability.Fertilization and...Background:In reclaimed land,the growth environment for plants may be unfavorable and the initial establishment and growth of seedlings could be limited because of low nutrient and water availability.Fertilization and control of understory vegetation that competes with seedlings may be of help in ameliorating soil physical and chemical properties,resulting in better seedling growth and reclamation success.However,the amount of nutrients understory vegetation absorbs in this ecological process has been rarely studied.Thus,we aimed to investigate the effect of soil amendment on biomass production and nutrient uptake by weeds in the nutrient-poor reclaimed area.We applied three levels of torrefied wood chip(TWC;0,2.5,and 5 Mg ha^(−1))and two levels of vermicompost(VC;0 and 2.7 Mg ha^(−1))as soil physical improvements and organic soil amendments in reclaimed land in the Republic of Korea,with Populus euramericana used as the crop tree.Results:TWC did not influence weed biomass,but 2.7 Mg ha^(−1) VC significantly increased weed biomass by 21%compared to 0 Mg ha^(−1) VC treatments.Nitrogen(N),phosphorus(P),potassium(K),calcium(Ca),magnesium(Mg),and sodium(Na)concentrations in weeds were the highest in control,but there was no statistical difference among treatments.However,VC treatment did marginally increase nutrient uptake in weeds,especially P,K,Ca,and Na.No treatments influenced crop tree height.Conclusion:We conclude that VC can be used as an organic source of nutrients in reclaimed soil and that weed management is necessary to increase treatment effects on crop trees in this salt-affected reclaimed land.展开更多
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2018R1D1A3B07045079)。
文摘Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production in three forests in Jeju Island differentiated by forest composition and precipitation: Cheongsu(Quercus glauca as the dominant species;low precipitation), Seonheulb(Q. glauca as the dominant species;high precipitation), and Seonheulm(Q. glauca and Pinus thunbergii as the dominant species;high precipitation). Litterfall was collected monthly from April to December 2015 and divided into leaf litter, twig, bark, seeds, and unidentified materials.Seasonal patterns of litterfall production varied across stands according to their species composition. However,the amount of leaf litterfall and total litterfall were comparable among stands, ranging from 362 to 375 g m-2 for leaf litter and 524 g m-2 to 580 g m-2 for total litterfall.Oak leaf litter in May was the highest in all stands, while needle litter was the highest in December in Seonheulm.High twig litterfall in July may be attributable to high rainfall with strong winds and storms during the rainy season. Although forest type and climate factor had no influence on litterfall amounts in this study, the pattern of litterfall production was species dependent, suggesting diverse effects on carbon and nutrient cycling in these forests.
基金supported by the Grant-in-Aid for Scientific Research of Japan Society for the Promotion of Science (JSPS KAKENHI) (Grant Nos.80378918,26292077)
文摘Although information regarding the initiation processes of debris flows is important for the development of mitigation measures,field data regarding these processes are scarce.We conducted field observations of debris-flow initiation processes in the upper Ichinosawa catchment of the Ohya landslide,central Japan.On 19 June 2012,our videocamera monitoring systems recorded the moment of debris-flow initiation on channel deposits(nine surges) and talus slopes(eight surges).The initiation mechanisms of these surges were classified into three types by analyzing the video images: erosion by the surface flow,movement of deposits as a mass,and upward development of the fluid area.The first type was associated with the progress of surface flow from the upper stream on unsaturated channel deposits.The second type was likely caused by an increase in the pore water pressure associated with the rising in the groundwater level in channel deposits;a continuous water supply from the upper stream by the surface flow might have induced this saturation.The third type was associated with changes in the downstream topography caused by erosion.The flow velocity of most surges was less than 3 m s^(-1) and they usually stopped within 100 m from the initiation point.Surges with abundant pore fluid had a higher flow velocity(about 3- 5 m s^(-1)) and could travel for alonger duration.Our observations indicate that the surface flow plays an important role in the initiation of debris flows on channel deposits and talus slopes.
文摘The management of forest corridors and related ecology is one of the effective strategies to minimize the adverse effects of forest degradation. It controls the connectivity of inhabitant species and the connection of the isolated patches. This study analyzed spatial and temporal forest physical degradation based on forest cover change and forest fragmentation in the Gishwati-Mukura biological corridor from 1990-2019. Remotely sensed datasets, Geographical Information System (GIS) and FRAGSTATS software were used to analyze the spatial and temporal physical degradation and changes in forest cover. The results indicated that the Gishwati-Mukura corridor experienced massive deforestation where approximately 7617.1 ha (64.22%) of forest cover was completely cleared out, which implies an annual forest loss of 262.6 ha·year<sup>-</sup><sup>1</sup> (2.21%) during 1990-2019. The forest cover transitions patterns and geostatistical analysis indicated that extensive deforestation was associated with intensive agriculture. The results demonstrated that agriculture has dramatically increased from 29.46% in 1990 to 57.22% in 2019, with an annual increase of 1.97%. Since Gishwati-Mukura has changed to National Park (NP), it lacks diversified scientific studies addressing the analysis of the remote and spatial patterns to investigate its physical degradation and landscape dynamics. This research study will serve as remote forest analysis gap-filling and as the cornerstone of numerous other research that will contribute to the improvement of the connectivity assessments along the Gishwati-Mukura corridor and other related ecosystems.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2021R1A2C201017812)support of‘R&D Program for Forest Science Technology(Project No.2022461B10-2424-0201)’provided by Korea Forest Service(Korea Forestry Promotion Institute)。
文摘Mammal distribution is shaped by different ecological and anthropogenic factors,and the pattern varies depending on their sensitivity thresholds,food and habitat preferences,ecological roles,and physical traits.The present study investigated the influence of ecological and anthropogenic factors on the distribution of mammal species communities across different trophic levels and body sizes in Myanmar's Htamanthi Wildlife Sanctuary(HWS).The values of mammal characteristics,ecological,and anthropogenic factors were analyzed in ArcMap software.Most of the large and small sized mammals,whose distribution decreases with elevation,were observed near the main streams.Across mammal tropic levels,the omnivores and herbivores were mostly observed farther from gold mining sites.In terms of forage plant effect on mammal community,floral forage plants and the presence of climber negatively affected mammal species across different trophic levels.Moreover,presence of resin trees also has a substantial impact on the distribution of medium-large animals and omnivorous mammals as trophic niche factors.Overall,our findings highlight the crucial role that ecological and anthropogenic factors play in shaping mammal distribution in the HWS.This underscores the importance of simultaneously conserving both habitat and mammal diversity in HWS,especially in the face of a changing climate and environment.
基金This study was funded by'R&D Program for Forest Science Technology(Project No.2018112D10-1920-BB01)'provided by Korea Forest Service(Korea Forestry Promotion Insttitute)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2018R1D1A3B07045079).
文摘Background:In reclaimed land,the growth environment for plants may be unfavorable and the initial establishment and growth of seedlings could be limited because of low nutrient and water availability.Fertilization and control of understory vegetation that competes with seedlings may be of help in ameliorating soil physical and chemical properties,resulting in better seedling growth and reclamation success.However,the amount of nutrients understory vegetation absorbs in this ecological process has been rarely studied.Thus,we aimed to investigate the effect of soil amendment on biomass production and nutrient uptake by weeds in the nutrient-poor reclaimed area.We applied three levels of torrefied wood chip(TWC;0,2.5,and 5 Mg ha^(−1))and two levels of vermicompost(VC;0 and 2.7 Mg ha^(−1))as soil physical improvements and organic soil amendments in reclaimed land in the Republic of Korea,with Populus euramericana used as the crop tree.Results:TWC did not influence weed biomass,but 2.7 Mg ha^(−1) VC significantly increased weed biomass by 21%compared to 0 Mg ha^(−1) VC treatments.Nitrogen(N),phosphorus(P),potassium(K),calcium(Ca),magnesium(Mg),and sodium(Na)concentrations in weeds were the highest in control,but there was no statistical difference among treatments.However,VC treatment did marginally increase nutrient uptake in weeds,especially P,K,Ca,and Na.No treatments influenced crop tree height.Conclusion:We conclude that VC can be used as an organic source of nutrients in reclaimed soil and that weed management is necessary to increase treatment effects on crop trees in this salt-affected reclaimed land.
