Rapid change of climate in vertical and considerable geomorphologic features form a typical diversity and distribution of biota in mountain ecosystems,i.e.,the subalpine forest zone(SFZ),the valley savanna zone(VSZ),a...Rapid change of climate in vertical and considerable geomorphologic features form a typical diversity and distribution of biota in mountain ecosystems,i.e.,the subalpine forest zone(SFZ),the valley savanna zone(VSZ),and the transition zone between them.The arid hot valley in the middle and lower reaches of Jinsha River,China represents a well target area to study distribution and the driving factors in these typical mountain ecosystems.Therefore,this study selects four sub-sample areas in the arid-hot valley to explore the distinctive changes of vegetation during 1990 to 2020,and their driving factors in the three different vegetation zones on spatiotemporal scales.On the spatial scale,the Moran’s index was applied to identify the transition zone between the SFZ and the VSZ.Results show that the VSZ at low altitudes(less than 600-1000 m from the valley bottom)is mainly affected by geomorphologic features,especially the slope aspect.With increase in altitude,the climate factors(e.g.,humidity,temperature,etc.)play a more significant role in the development of the SFZ,while the effect of geomorphologic features gradually weakens.On the time scale,The SFZ at higher altitudes experienced more rapid changes in temperature(temperature increase of 1.41°C over the last 60 years)than the VSZ at lower altitudes(temperature increase of 0.172°C over the past 60 years).It caused the forest cover increase faster than that of savanna grassland.Humidity and heat conditions are altered by topography and climate conditions,which shapes the development and physiology of plants as they adapt to the different climatic zones.Furthermore,according to the driving factors(geomorphologic and climate factors)of vegetation distribution found in this study,it suggests that suitable tree species should be planted in the transition zone to evolve into the forest zone and making the forest zone to recover from high to low altitudes gradually.展开更多
Vegetation in hot and arid valleys is a crucial indicator of ecosystem health,but is vulnerable to human activities and environmental change.Using the Longkaikou Reservoir in the Jinsha River in southwestern China as ...Vegetation in hot and arid valleys is a crucial indicator of ecosystem health,but is vulnerable to human activities and environmental change.Using the Longkaikou Reservoir in the Jinsha River in southwestern China as a case study,we developed a spatially explicit model that combined the plant growth,fruiting,seed dispersal,and seed germination stages to reveal the potential impact of multiple human activities(reservoir construction,logging,grazing,and aerial seeding) on the vegetation dynamics of Dodonaea viscosa and Pinus yunnanensis.After reservoir construction,the grassland area of 68 km^(2) in 2003 decreased to 24 km^(2) in 2018,replaced by forest,shrubland,and bodies of water,and the precipitation increased during the dry season,which indicated the improvement of the local plant and soil environment.Our model predicted that when soil moisture decreased by more than 20% compared to current levels,the area of D.viscosa increased greatly at low elevations;however,when at higher soil moisture,P.yunnanensis would occupy more of the study area.Logging and grazing would slightly change the spatial pattern of vegetation and delay P.yunnanensis communities from achieving stability by directly reducing plant biomass.Countermeasures such as aerial seeding would increase the total area by 13.13 km^(2) and 8.09 km^(2) of two plants,respectively,and accelerate the stabilization of plant communities.The effects of multiple human activities on vegetation may counteract each other;for example,logging decreased the P.yunnanensis area whereas aerial seeding increased it,and plant biomass changed in response to this pressure.Given the complex relationships between vegetation and human impacts,our study provides a scientific basis for vegetation restoration and ecological security in this hot and arid valley.展开更多
基金supported by China National Funds for Distinguished Young Scientists(Grant No.52025092)the Fundamental Research Funds for the Central Universities(Grant No.JB2022059)。
文摘Rapid change of climate in vertical and considerable geomorphologic features form a typical diversity and distribution of biota in mountain ecosystems,i.e.,the subalpine forest zone(SFZ),the valley savanna zone(VSZ),and the transition zone between them.The arid hot valley in the middle and lower reaches of Jinsha River,China represents a well target area to study distribution and the driving factors in these typical mountain ecosystems.Therefore,this study selects four sub-sample areas in the arid-hot valley to explore the distinctive changes of vegetation during 1990 to 2020,and their driving factors in the three different vegetation zones on spatiotemporal scales.On the spatial scale,the Moran’s index was applied to identify the transition zone between the SFZ and the VSZ.Results show that the VSZ at low altitudes(less than 600-1000 m from the valley bottom)is mainly affected by geomorphologic features,especially the slope aspect.With increase in altitude,the climate factors(e.g.,humidity,temperature,etc.)play a more significant role in the development of the SFZ,while the effect of geomorphologic features gradually weakens.On the time scale,The SFZ at higher altitudes experienced more rapid changes in temperature(temperature increase of 1.41°C over the last 60 years)than the VSZ at lower altitudes(temperature increase of 0.172°C over the past 60 years).It caused the forest cover increase faster than that of savanna grassland.Humidity and heat conditions are altered by topography and climate conditions,which shapes the development and physiology of plants as they adapt to the different climatic zones.Furthermore,according to the driving factors(geomorphologic and climate factors)of vegetation distribution found in this study,it suggests that suitable tree species should be planted in the transition zone to evolve into the forest zone and making the forest zone to recover from high to low altitudes gradually.
基金financially supported by the National Key R&D Plan of China (No.2016YFC0502209)the NSFC-Shandong Joint Fund (No.U1806217)+1 种基金the National Natural Science Foundation of China (No.52009006)the Interdiscipline Research Funds of Beijing Normal University。
文摘Vegetation in hot and arid valleys is a crucial indicator of ecosystem health,but is vulnerable to human activities and environmental change.Using the Longkaikou Reservoir in the Jinsha River in southwestern China as a case study,we developed a spatially explicit model that combined the plant growth,fruiting,seed dispersal,and seed germination stages to reveal the potential impact of multiple human activities(reservoir construction,logging,grazing,and aerial seeding) on the vegetation dynamics of Dodonaea viscosa and Pinus yunnanensis.After reservoir construction,the grassland area of 68 km^(2) in 2003 decreased to 24 km^(2) in 2018,replaced by forest,shrubland,and bodies of water,and the precipitation increased during the dry season,which indicated the improvement of the local plant and soil environment.Our model predicted that when soil moisture decreased by more than 20% compared to current levels,the area of D.viscosa increased greatly at low elevations;however,when at higher soil moisture,P.yunnanensis would occupy more of the study area.Logging and grazing would slightly change the spatial pattern of vegetation and delay P.yunnanensis communities from achieving stability by directly reducing plant biomass.Countermeasures such as aerial seeding would increase the total area by 13.13 km^(2) and 8.09 km^(2) of two plants,respectively,and accelerate the stabilization of plant communities.The effects of multiple human activities on vegetation may counteract each other;for example,logging decreased the P.yunnanensis area whereas aerial seeding increased it,and plant biomass changed in response to this pressure.Given the complex relationships between vegetation and human impacts,our study provides a scientific basis for vegetation restoration and ecological security in this hot and arid valley.
