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Temporal trends of hydro-climatic variables and their relevance in water resource management

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International Journal of Sediment Research 2021年第1期36卷 63-75页

作者： Karim Solaimani Mahmoud Habaibnejad Abdollah Pirnia GIS centre University of Agricultural and Natural Resources of Sari Department of Watershed management University of Agricultural and Natural Resources of Sari

Identification of temporal changes in hydrological regimes of river basins is an important topic in contemporary hydrology because of the potential impacts of climate change on river flow regimes.For this purpose,long-term historical records of rainfall(P),runoff(Q) and other climatic factors were used to investigate hydrological variability and trends in the Tajan River Basin over the period 1969-1998.Actual evaporation(E),rainfall variability index(d),evaporation ratio(CE) and runoff ratio(CQ) were estimated from the available hydroclimatological records.Mann-Kendall trend analysis and nonparametric Sen’s slope estimates were performed on the respective time series variables to detect monotonic trend direction and magnitude of change over time.Rainfall variability index showed that1973 was the wettest year(δ=+2.039) while 1985 was the driest(δ=-1.584).Also,decades 69-78 and89-98 were recognized as the wettest and driest decades respectively.The gradient of variation of climatological parameters showed that during the study period,all three parameters of rainfall,evaporation and runoff have decreased and the variations of rainfall and evaporation were significant at the95% level.Investigation of hydrological changes due of dam construction(1999) showed that the amount and annual distribution of discharge were completely different pre and post-dam construction.Discharge decreased in high water months and increased in low water months to meet water supply demands,especially for agriculture.The relationship between temperature and rainfall trends is compared for three stations in Mazandaran Province(Gorgan,Babolsar and Ramsar) from 1956 to 2003 and nine other stations with different statistical periods of 19-36 years,relating trends to northern hemisphere and global trends.Decreases in temperature were accompanied by decreases in rainfall,and vice versa.These trends were not observed in northern hemisphere and world scales,where temperature increases are accompanied by decreases in rainfall.These variations of hydr

关键词： Climate change Human activity Hydroclimatological Trend analysis Mazandaran Tajan basin

Satellite Remote Sensing of Savannas:Current Status and Emerging Opportunities

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Journal of Remote Sensing 2022年第1期2022卷 162-181页

作者： Abdulhakim M.Abdi Martin Brandt Christin Abel Rasmus Fensholt Department of Geosciences and natural resource management University of CopenhagenCopenhagenDenmark centre for Environmental and Climate Science Lund UniversityLundSweden

Savannas cover a wide climatic gradient across large portions of the Earth’s land surface and are an important component of the terrestrial biosphere.Savannas have been undergoing changes that alter the composition and structure of their vegetation such as the encroachment of woody vegetation and increasing land-use intensity.Monitoring the spatial and temporal dynamics of savanna ecosystem structure(e.g.,partitioning woody and herbaceous vegetation)and function(e.g.,aboveground biomass)is of high importance.Major challenges include misclassification of savannas as forests at the mesic end of their range,disentangling the contribution of woody and herbaceous vegetation to aboveground biomass,and quantifying and mapping fuel loads.Here,we review current(2010–present)research in the application of satellite remote sensing in savannas at regional and global scales.We identify emerging opportunities in satellite remote sensing that can help overcome existing challenges.We provide recommendations on how these opportunities can be leveraged,specifically(1)the development of a conceptual framework that leads to a consistent definition of savannas in remote sensing;(2)improving mapping of savannas to include ecologically relevant information such as soil properties and fire activity;(3)exploiting high-resolution imagery provided by nanosatellites to better understand the role of landscape structure in ecosystem functioning;and(4)using novel approaches from artificial intelligence and machine learning in combination with multisource satellite observations,e.g.,multi-/hyperspectral,synthetic aperture radar(SAR),and light detection and ranging(lidar),and data on plant traits to infer potentially new relationships between biotic and abiotic components of savannas that can be either proven or disproven with targeted field experiments.

关键词： structure Remote lidar

Macroinvertebrates in the bed sediment of the Yellow River

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International Journal of Sediment Research 2011年第3期26卷 255-268页

作者： Paul G.CLOSE centre of Excellence in natural resource management The University of Western AustraliaP.O.Box 5771AlbanyWestern Australia 6330Australia

Extensive agricultural,industrial and urban development in the Yellow River,China,have modified the sediment-water balance,flow and inundation regimes,longitudinal connectivity,integrity of riparian vegetation,and water quality.Macroinvertebrate assemblages in the bed sediment of main channel and major reservoirs of the Yellow River are described in detail for the first time.A total of 74 taxa comprising 17 taxa of oligochaetes,48 taxa of aquatic insects,5 taxa of molluscs,and 4 taxa of other animals were recorded.A range of feeding guilds were represented,including, collector-gatherers(32 taxa),predators(17 taxa),scrapers(16 taxa),shredders(6 taxa)and collector-filterers(2 taxa).Both the mean density and biomass of macroinvertebrates were significantly higher in sites located in the artificial reservoirs compared with the main river channel. Assemblages varied spatially;Oligochaetes dominated assemblages in upper reaches,insects dominated in middle reaches and other animals(e.g.Crustacea)dominated in lower reaches. Collector-gatherers were dominant throughout the entire river.Classification analysis identified five site-groups on the basis of macroinvertebrate presence/absence:downstream of reservoirs;vegetated sites;reservoir sites;polluted sites,and;lower-reach sites.Lower macroinvertebrate richness,density and biomass,compared with other similar large rivers,were attributed to modification of the sediment-water balance and associated disturbance of benthic habitats.Pollution,stability of sediment and sediment concentration combined to influence the distribution of macroinvertebrates.This knowledge will substantially benefit the recent focus on the health and environmental water requirements of the Yellow River.

关键词： Macroinvertebrates Species composition Distribution pattern Sediment The Yellow River

Effect of drainage on CO_2, CH_4, and N_2O fluxes from aquaculture ponds during winter in a subtropical estuary of China

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Journal of Environmental Sciences 2018年第3期30卷 72-82页

作者： Ping Yang Derrick Y.F Lai Jia F.Huang Chuan Tong School of Geographical Sciences Fujian Normal University Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education of China Fujian Normal University Department of Geography and resource management and Centre for Environmental Policy and Resource ManagementThe Chinese University of Hong Kong

Aquaculture ponds are dominant features of the landscape in the coastal zone of China.Generally,aquaculture ponds are drained during the non-culture period in winter.However,the effects of such drainage on the production and flux of greenhouse gases（GHGs）from aquaculture ponds are largely unknown.In the present study,field-based research was performed to compare the GHG fluxes between one drained pond（DP,with a water depth of 0.05 m）and one undrained pond（UDP,with a water depth of 1.16 m）during one winter in the Min River estuary of southeast China.Over the entire study period,the mean CO2flux in the DP was（0.75±0.12）mmol/（m^2·hr）,which was significantly higher than that in the UDP of（-0.49±0.09）mmol/（m^2·hr）（p0.01）.This indicates that drainage drastically transforms aquaculture ponds from a net sink to a net source of CO2in winter.Mean CH4and N2O emissions were significantly higher in the DP compared to those in the UDP（CH4=（0.66±0.31）vs.（0.07±0.06）mmol/（m^2·hr）and N2O=（19.54±2.08）vs.（0.01±0.04）μmol/（m^2·hr））（p〈0.01）,suggesting that drainage would also significantly enhance CH4and N2O emissions.Changes in environmental variables（including sediment temperature,p H,salinity,redox status,and water depth）contributed significantly to the enhanced GHG emissions following pond drainage.Furthermore,analysis of the sustained-flux global warming and cooling potentials indicated that the combined global warming potentials of the GHG fluxes were significantly higher in the DP than in the UDP（p〈0.01）,with values of739.18 and 26.46 mg CO2-eq/（m^2·hr）,respectively.Our findings suggested that drainage of aquaculture ponds can increase the emissions of potent GHGs from the coastal zone of China to the atmosphere during winter,further aggravating the problem of global warming.

关键词： Aquaculture pond Drainage management Greenhouse gas flux Global warming Min River estuary

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Root System Traits Contribute to Variability and Plasticity in Response to Phosphorus Fertilization in 2 Field-Grown Sorghum[Sorghum bicolor(L.)Moench]Cultivars

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Plant Phenomics 2023年第1期5卷 6-21页

作者： Michael O.Adu Paul A.Asare David O.Yawson Kwadwo K.Amoah Kofi Atiah Matthew K.Duah Alex Graham Department of Crop Science School of AgricultureCollege of Agriculture and Natural SciencesUniversity of Cape CoastCape CoastGhana centre for resource management and Environmental Studies(CERMES) The University of the West IndiesCave Hill CampusP.O.Box 64Bridgetown BB11000Barbados Department of Soil Science School of AgricultureCollege of Agriculture and Natural SciencesUniversity of Cape CoastCape CoastGhana

Due to roots'physical and physiological roles in crop productivity,interest in root system architecture(RSA)and plasticity in responses to abiotic stresses is growing.Sorghum is significant for the food security of millions of people.Phosphorus deficiency is an important limitation of sorghum productivity.There is little information on the RSA-based responses of sorghum to variations in external P supply([P]_(ext)).This study evaluated the phenotypic plasticity and RSA responses to a range of[P]_(ext) in 2 sorghum genotypes.The results showed that both genotypes responded to[P]_(ext) but with significant variations in about 80%of the RSA traits analyzed.Aboveground biomass and most RSA traits increased with increasing[P]_(ext).Plasticity was both genotype-and trait-dependent.For most RSA traits,the white sorghum genotype showed significantly higher plasticity than the red genotype,with the former having about 28.4%higher total plasticity than the former.RSA traits,such as convex area,surface area,total root length,and length diameter ranges,showed sizeable genetic variability.Root biomass had a high degree of plasticity,but root number and angle traits were the leading contributors to variation.The results suggested 2 root trait spectra:root exploration and developmental spectrum,and there was an indication of potential trade-offs among groups of root traits.It is concluded that RSA traits in sorghum contribute to variability and plasticity in response to[P]_(ext).Given that there might be trade-offs among sorghum root traits,it would be instructive to determine the fundamental constraints underlying these trade-offs.

关键词： Root instru constraints

Soil and water conservation practice effects on soil physicochemical properties and crop yield in Ethiopia:review and synthesis

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Ecological Processes 2022年第1期11卷 206-221页

作者： Endale Bekele Jiru Habtamu Temesgen Wegari College of Agriculture and natural resource Dilla UniversityDillaEthiopia College of Agriculture and natural resource Bonga UniversityBongaEthiopia

Background:Land degradation is an urgent agenda that requires great effort and resources to ameliorate.It worsens soil components through disrupting ecological functions and threatens agriculture production.To overcome it,different soil and water conservation(SWC)practices have been undertaken in numerous parts of Ethiopia.This paper aims to review the effects of SWC practices on soil physicochemical properties and crop yield.Data were collected from secondary sources via a computer library using various databases based on developed criteria.The collected data were organized,categorized,and analyzed through descriptive statistics.The mean difference of selected soil physicochemical properties obtained from treated and untreated farmland was tested using paired t-test.Factors influencing crop yield on treated farmland were determined by a multiple linear regression model.Results:SWC practices influenced the soil physicochemical properties and crop yield either positively or negatively.The mean values of available phosphorus(10.6 ppm,8.7 ppm),total nitrogen(0.5%,0.4%),soil pH(6.0%,5.8%),soil organic matter(4.4%,3.8%),and soil organic carbon(2.2%,1.8%)were on treated and untreated farmland under physical SWC practices,respectively.Similarly,the mean values of these variables were higher on treated farmland than untreated farmland under both biological and integrated SWC practices.The mean value of bulk density was higher on untreated farmland than treated one and statistically significant under all SWC practices.Fanya juu and stone-faced soil bund constantly increased crop yield,whereas soil bund and stone bund did not.Conclusion:Proper implementation of SWC technologies through integrating physical and biological measures will boost the effectiveness of the practice in restoring soil physicochemical properties and improving crop yield.Meanwhile,government due attention paid for land resources management in Ethiopia,whereby the annual SWC and tree planting campaign underwent for a couple of decades,entails further s

关键词： Land degradation Soil and water conservation Crop yield Soil physicochemical properties

A comparison of fecal sampling and direct feeding observations for quantifying the diet of a frugivorous primate

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Current Zoology 2020年第4期66卷 333-343页

作者： Jaya K.MATTHEWS Amanda R.IDLEY Beth A.KApuN Cyril C.GRUETER School of Human Sciences The University of Western AustraliaCrawleyWA 6009Australia UWA Africa Research&Engagement centre The University of Western AustraliaCrawleyWA 6009Australia centre for Evolutionary Biology School of Biological SciencesThe University of Western AustraliaCrawleyWA 6009Australia centre of Excellence in Biodiversity and natural resource management University of RwandaHuyeRwanda School for the Environment University of MassachusettsBostonMA 02125-3393USA

Both observational and indirect evidence are widely used to determine the diets of wild animals.Direct observations are often assumed to provide the most comprehensive reflection of diet,but many wild animals are logistically challenging to observe.Despite the regular use of observa-tional and indirect methods for inferring diet in wild animals,they have rarely been compared in detail for the same study population.Over 12 months this study assessed the congruence of methods in estimating the diet of a montane community of eastern chimpanzees Pan troglodytes schweinfurthii in Nyungwe National Park,Rwanda using observational scan samples and macro-scopic fecal inspection.The assessment of the number of food species consumed each month was comparable between methods,but the estimation of the composition of items in the diet differed significantly.Most notably,the fecal samples significantly underestimated the consumption of flowers,and certain fruit species,which based on direct behavioral observations were seasonally consumed at very high rates.Conversely,direct observations underestimated the consumption of leaves and pith in comparison to results present in the fecal samples.These results suggest that combining methods where possible is most useful for accurate monitoring of dietary trends,particularly for species that experience significant seasonal shifts in their diet.

关键词： chimpanzee comparative methods dietary analysis seasonality

People’s perception and socioeconomic determinants of soil erosion:A case study of Samanalawewa watershed, Sri Lanka

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International Journal of Sediment Research 2010年第4期25卷 323-339页

作者： E.P.N. UDAYAKUMARA R.P.SHRESTHA L.SAMARAKOON D.SCHMIDT-VOGT natural resource management Field of Study School of Environment Resources and Development Asian Institute of Technology natural resources management Field of Study School of Environment Resources and Development Asian Institute of Technology Geoinformatics centre Asian Institute of Technology centre of Mountain Ecosystem Studies Kunming Institute of Botany Chinese Academy of Sciences 3/F Library Building Heilongtan

Though soil erosion is an important concern in Sri Lanka, there is a dearth of baseline information on soil erosion in many ofits watersheds, which obstructs monitoring of soil erosion and mitigating its effects. In order to assess soil erosion in a critical watershed and to identify its determinants, the Samanalawewa watershed, which contains one of the main hydropower generating reservoirs in Sri Lanka, was selected for this study. Remote-sensing (RS) and geographic information system (GIS) based modeling as well as field experiments were employed to assess and map soil erosion rates. Results indicated that the current rate of soil erosion ranges from 0 to 289 t/ha/yr, and that the average rate of soil erosion has been declining from 20 to 4 t/ha/yr over a period from 1986 to 2008. The current rate of soil erosion is, however, still about 14 to 33 times greater than the natural soil generation rate. Socioeconomic factors and peoples’ perception of soil erosion and soil conservation measures were examined using data collected through a household survey. Multiple regression analysis with eighteen covariates of socioeconomic characteristics yielded eleven socioeconomic variables, viz. household size, farm labor, education, land tenure, conservation cost, training, committee membership, professional competencies, income, distance, and financial capital as the predictor variables of soil erosion. Farmers identified improper soil and crop management practices as the major causes of erosion. The adoption of conservation measures, their effectiveness, and their impact on ecosystem services were also examined.

关键词： Soil erosion People perception Determinants of soil erosion Conservation measures Sri Lanka

A methodological framework for analyzing PPGIS data collected in 3D

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International Journal of Digital Earth 2023年第1期16卷 3435-3455页

作者： Kamyar Hasanzadeh Nora Fagerholm Hans Skov-Petersen Anton Stahl Olafsson Department of Geography and Geology University of TurkuTurkuFinland Department of Geosciences and natural resource management University of CopenhagenCopenhagenDenmark

Public participation geographic information system(PPGIS)is a facilitated Volunteered Geographic Information approach and data collection method that aims to capture the spatial experiences of individuals.Although we experience the space around us three-dimensionally,altitude,as the third dimension,has been often absent from PPGis research and practice.This is largely because of the complexity of implementing surveys in 3D but can also be attributed to a lack of analytical preparedness for using such data.This study complements 3D PPGIS data collected from a pilot study of the Aninkainen block in Turku,Finland with synthetic,i.***.artificially manufactured,data to propose an analytical framework for the study of 3D PPGIS data.The analytical framework divides methods based on the geographical scale into two groups:micro-and macro-scale analysis.In this framework,we propose the use of geospatial metrics to analyze 3D PPGIS data.We argue that while this multidisciplinary area of research is in its infancy,use of intuitive 3D adapted geometric and landscape metrics can help overcome some of complexities associated with use of this emerging participatory data.We conclude by outlining the limitations and envisioning areas for future research.

关键词： 3D GIS landscape metrics PPGIS