Microtopography affects hydrological processes and forms different microhabitats.Our previous study uncovered that riparian zone microtopography created various microhabitats with different soil environments and runof...Microtopography affects hydrological processes and forms different microhabitats.Our previous study uncovered that riparian zone microtopography created various microhabitats with different soil environments and runoff-infiltration patterns.However,how riparian microtopography and microtopography within the water area(waterfall and tributary)affects downstream water quality remains unclear.Therefore,water samples were taken almost monthly in both the main stream and the tributary,before and after waterfalls,and near the bottom of three microtopographic types from June 2016 to March 2017.Compared with the dry season,the fact that water quality worsened in the wet season and that there were positive correlations for nitrate(NO3-)between water and the corresponding soil samples suggested that the riparian-soil environment affected the adjacent water quality mainly in the wet season.Nevertheless,riparian microtopography did not influence water quality downstream because of the low rainfall frequency and the weak leaching process due to plant interception.In the wet season,both the tributary and the waterfall increased the dissolved oxygen in the water body and,therefore,lowered the risk of eutrophication.The tributary has two pathways for improving the water quality,by increased disturbance and flow velocity,while the waterfall only has the former.However,such effects were not significant in the dry season.We conclude that the application of microtopographic modification is useful in maintaining urban wetland water quality in wet seasons.展开更多
Rocky outcrops function as island-like environmental filters and pivotal ecological refuges for local and regional biodiversity,with their inherent topographic and microclimatic dynamics directly shaping vegetation co...Rocky outcrops function as island-like environmental filters and pivotal ecological refuges for local and regional biodiversity,with their inherent topographic and microclimatic dynamics directly shaping vegetation composition and distribution across slopes.This study inventoried the flora of a rocky outcrop slope within Brazil's Caatinga biome,a seasonally dry tropical forest,to analyze species distribution patterns and their relationship with microtopographic conditions.The slope was stratified into base,middle and top segments according to slope gradient,with specimens collected over seven months of field expeditions,followed by taxonomic processing to compile a floristic inventory.The survey documented 60 species,53 genera,and 28 families,with Fabaceae,Euphorbiaceae,and Malvaceae emerging as the most representative families;herbaceous species dominated,followed by trees and shrubs.Species richness declined along the topographic gradient as altitude increased,with 43%of flora comprising species widespread across Brazilian biomes and 20%endemic to the Caatinga.Variations in species distribution across slope positions suggest that topographic heterogeneity may drive distinct pedological and microclimatic conditions,directly influencing vegetation dynamics in rock outcrops.These findings underscore the role of microtopography in structuring plant communities in harsh environments.展开更多
Aeolian sandy lands are widespread and desertification is recognized as one of the main environmental issues in the Yarlung Zangbo River valley,southern Tibetan plateau.The surface microtopographic var-iations induced...Aeolian sandy lands are widespread and desertification is recognized as one of the main environmental issues in the Yarlung Zangbo River valley,southern Tibetan plateau.The surface microtopographic var-iations induced by the near soil surface characteristics of plant communities are important compositions of land surface roughness,which likely influence wind erosion.This study was conducted to quantify the effects of typical vegetation restoration on land surface roughness on the aeolian sandy lands,and to identify the main influencing factors of land surface roughness in the Yarlung Zangbo River valley.Two bare sandy lands(as controls)and eight vegetated sandy lands with different restoration communities and ages were selected,and land surface roughness(LSR),as represented by surface microtopographic variations in this study,was measured by photogrammetric surveys.The results showed that LSR significantly increased by 7.9-16.8 times after vegetation restoration on the aeolian sandy lands,and varied among different restoration communities and ages.The mostly restored communities of Sophora moorcroftiana and Populus L.had greater LSR as compared to Artemisia wellbyi and Hedysarum scoparium.With succession from 6 to over 30 years,LSR gradually increased in the Sophora moorcroftiana restored sandy lands,but decreased in the Populus L restored sandy lands.The variations of LSR were mainly attributed to the differences in near soil surface characteristics of vegetation(plant stem diameter and coverage,and plant residue density)and biological soil crusts(coverage and thickness).Mixed plantation of Populus L and Sophora moorcroftiana was considered as the best restoration communities because of their effectiveness in increasing land surface roughness on the aeolian sandy lands in the Yarlung Zangbo River valley.The results would facilitate the understanding of the benefits of vegetation restoration in controlling wind erosion on the aeolian sandy lands.展开更多
基金supported by the National Natural Science Foundation of China(No.41571482)the State Key Laboratory of Urban&Regional Ecology(No.SKLURE2017-1-1)
文摘Microtopography affects hydrological processes and forms different microhabitats.Our previous study uncovered that riparian zone microtopography created various microhabitats with different soil environments and runoff-infiltration patterns.However,how riparian microtopography and microtopography within the water area(waterfall and tributary)affects downstream water quality remains unclear.Therefore,water samples were taken almost monthly in both the main stream and the tributary,before and after waterfalls,and near the bottom of three microtopographic types from June 2016 to March 2017.Compared with the dry season,the fact that water quality worsened in the wet season and that there were positive correlations for nitrate(NO3-)between water and the corresponding soil samples suggested that the riparian-soil environment affected the adjacent water quality mainly in the wet season.Nevertheless,riparian microtopography did not influence water quality downstream because of the low rainfall frequency and the weak leaching process due to plant interception.In the wet season,both the tributary and the waterfall increased the dissolved oxygen in the water body and,therefore,lowered the risk of eutrophication.The tributary has two pathways for improving the water quality,by increased disturbance and flow velocity,while the waterfall only has the former.However,such effects were not significant in the dry season.We conclude that the application of microtopographic modification is useful in maintaining urban wetland water quality in wet seasons.
基金CAPES(Coordenacao de Aperfeicoamento de Pessoal de Nível Superior)for the master's scholarship(Proc.n.88887.822653/202300)CNPq(Conselho Nacional de Desenvolvimento Científico e Tecnológico-Brazil)for the PIBIC scholarship(Call 03/2023-UEPB/CNPq)+3 种基金CAPES(Coordenacco de Aperfeicoamento de Pessoal de Nível Superior)for the doctoral scholarship(Proc.n.88887.948069/202400)CAPES(Coordenacco de Aperfeicoamento de Pessoal de Nível Superior)for the doctoral scholarship(Proc.n.88887.995048/2024-00)CAPES(Coordenacco de Aperfeicoamento de Pessoal de Nível Superior)for the doctoral scholarship(Proc.n.88887.497186/202000)CNPq for the Research Productivity fellowship。
文摘Rocky outcrops function as island-like environmental filters and pivotal ecological refuges for local and regional biodiversity,with their inherent topographic and microclimatic dynamics directly shaping vegetation composition and distribution across slopes.This study inventoried the flora of a rocky outcrop slope within Brazil's Caatinga biome,a seasonally dry tropical forest,to analyze species distribution patterns and their relationship with microtopographic conditions.The slope was stratified into base,middle and top segments according to slope gradient,with specimens collected over seven months of field expeditions,followed by taxonomic processing to compile a floristic inventory.The survey documented 60 species,53 genera,and 28 families,with Fabaceae,Euphorbiaceae,and Malvaceae emerging as the most representative families;herbaceous species dominated,followed by trees and shrubs.Species richness declined along the topographic gradient as altitude increased,with 43%of flora comprising species widespread across Brazilian biomes and 20%endemic to the Caatinga.Variations in species distribution across slope positions suggest that topographic heterogeneity may drive distinct pedological and microclimatic conditions,directly influencing vegetation dynamics in rock outcrops.These findings underscore the role of microtopography in structuring plant communities in harsh environments.
基金This work was supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0404)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20020401)the“Light of West China”Program of the Chinese Academy of Sciences(E0R2180)。
文摘Aeolian sandy lands are widespread and desertification is recognized as one of the main environmental issues in the Yarlung Zangbo River valley,southern Tibetan plateau.The surface microtopographic var-iations induced by the near soil surface characteristics of plant communities are important compositions of land surface roughness,which likely influence wind erosion.This study was conducted to quantify the effects of typical vegetation restoration on land surface roughness on the aeolian sandy lands,and to identify the main influencing factors of land surface roughness in the Yarlung Zangbo River valley.Two bare sandy lands(as controls)and eight vegetated sandy lands with different restoration communities and ages were selected,and land surface roughness(LSR),as represented by surface microtopographic variations in this study,was measured by photogrammetric surveys.The results showed that LSR significantly increased by 7.9-16.8 times after vegetation restoration on the aeolian sandy lands,and varied among different restoration communities and ages.The mostly restored communities of Sophora moorcroftiana and Populus L.had greater LSR as compared to Artemisia wellbyi and Hedysarum scoparium.With succession from 6 to over 30 years,LSR gradually increased in the Sophora moorcroftiana restored sandy lands,but decreased in the Populus L restored sandy lands.The variations of LSR were mainly attributed to the differences in near soil surface characteristics of vegetation(plant stem diameter and coverage,and plant residue density)and biological soil crusts(coverage and thickness).Mixed plantation of Populus L and Sophora moorcroftiana was considered as the best restoration communities because of their effectiveness in increasing land surface roughness on the aeolian sandy lands in the Yarlung Zangbo River valley.The results would facilitate the understanding of the benefits of vegetation restoration in controlling wind erosion on the aeolian sandy lands.
