Spatially explicit modeling plays a vital role in land use/cover change and urbanization research as well as resources management;however,current models lack proper validation and fail to incorporate uncertainty into ...Spatially explicit modeling plays a vital role in land use/cover change and urbanization research as well as resources management;however,current models lack proper validation and fail to incorporate uncertainty into the formulation of model predictions.Consequently,policy makers and the general public may develop opinions based on potentially misleading research,which fails to allow for truly informed decisions.Here we use an uncertainty strategy of spatially explicit modeling combined with the series statistic of Kappa index for location and quantity to estimate the uncertainty of future predications and to determine model accuracy.We take the Beijing metropolitan area as an example to demonstrate the uncertainty in extrapolations of predictive land use change and urban sprawl with spatially explicit modeling at multiple resolutions.The sensitivity of scale effects is also discussed.The results show that an improvement in specification of location is more helpful in increasing accuracy as compared to an improvement in the specification of quantity at fine spatial resolutions.However,the spatial scale has great effects on modeling accuracy and correct due to chance tends to increase as resolution becomes coarser.The results allow us to understand the uncertainty when using spatially explicit models for land-use change or urbanization estimates.展开更多
Potato virus Y(PVY)is a non-persistent virus that is transmitted by many aphid species and causes significant damage to potato production.We constructed a spatially-explicit model simulating PVY spread in a potato fie...Potato virus Y(PVY)is a non-persistent virus that is transmitted by many aphid species and causes significant damage to potato production.We constructed a spatially-explicit model simulating PVY spread in a potato field and used it to investigate possible effects of transmission efficiency,initial inoculum levels,vector behavior,vector abundance,and timing of peak vector activity on PVY incidence at the end of a simulated growing season.Lower PVY incidence in planted seed resulted in lower virus infection at the end of the season.However,when populations of efficient PVY vectors were high,significant PVY spread occurred even when initial virus inoculum was low.Non-colonizing aphids were more important for PVY spread compared to colonizing aphids,particularly at high densities.An early-season peak in the numbers of noncolonizing aphids resulted in the highest number of infected plants in the end of the season,while mid-and late-season peaks caused relatively little virus spread.Our results highlight the importance of integrating different techniques to prevent the number of PVY-infected plants from exceeding economically acceptable levels instead of trying to control aphids within potato fields.Such management plans should be implemented very early in a growing season.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
In this paper,the development of Individual-based Spatial Explicit Landscape Model was outlined at first.Then several issues,pertaining to develop Individual-based Spatial Explicit Landscape Models,were discussed in d...In this paper,the development of Individual-based Spatial Explicit Landscape Model was outlined at first.Then several issues,pertaining to develop Individual-based Spatial Explicit Landscape Models,were discussed in details.And at last,the application perspectives of such models were illustrated,including animal movement,plant competition and landscape change.This study has relatively important significance guiding roles in developing Individual-based Spatial Explicit Landscape Model in our country and in landscape management.展开更多
基金supported by China Postdoctoral Science Foundation (Grant No.20070420630)National Basic Research Program of China (Grant Nos.2002CB412507,G19990435)
文摘Spatially explicit modeling plays a vital role in land use/cover change and urbanization research as well as resources management;however,current models lack proper validation and fail to incorporate uncertainty into the formulation of model predictions.Consequently,policy makers and the general public may develop opinions based on potentially misleading research,which fails to allow for truly informed decisions.Here we use an uncertainty strategy of spatially explicit modeling combined with the series statistic of Kappa index for location and quantity to estimate the uncertainty of future predications and to determine model accuracy.We take the Beijing metropolitan area as an example to demonstrate the uncertainty in extrapolations of predictive land use change and urban sprawl with spatially explicit modeling at multiple resolutions.The sensitivity of scale effects is also discussed.The results show that an improvement in specification of location is more helpful in increasing accuracy as compared to an improvement in the specification of quantity at fine spatial resolutions.However,the spatial scale has great effects on modeling accuracy and correct due to chance tends to increase as resolution becomes coarser.The results allow us to understand the uncertainty when using spatially explicit models for land-use change or urbanization estimates.
基金supported in part by the United States Department of Agriculture National institute of Food and Agriculture Special Crops Research initiative (Award # 2014-51181-22373)Funding for Hongchun Qu’s stay at the University of Maine was received from the National Natural Science Foundation of China (Award # 61871061)
文摘Potato virus Y(PVY)is a non-persistent virus that is transmitted by many aphid species and causes significant damage to potato production.We constructed a spatially-explicit model simulating PVY spread in a potato field and used it to investigate possible effects of transmission efficiency,initial inoculum levels,vector behavior,vector abundance,and timing of peak vector activity on PVY incidence at the end of a simulated growing season.Lower PVY incidence in planted seed resulted in lower virus infection at the end of the season.However,when populations of efficient PVY vectors were high,significant PVY spread occurred even when initial virus inoculum was low.Non-colonizing aphids were more important for PVY spread compared to colonizing aphids,particularly at high densities.An early-season peak in the numbers of noncolonizing aphids resulted in the highest number of infected plants in the end of the season,while mid-and late-season peaks caused relatively little virus spread.Our results highlight the importance of integrating different techniques to prevent the number of PVY-infected plants from exceeding economically acceptable levels instead of trying to control aphids within potato fields.Such management plans should be implemented very early in a growing season.
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.
文摘In this paper,the development of Individual-based Spatial Explicit Landscape Model was outlined at first.Then several issues,pertaining to develop Individual-based Spatial Explicit Landscape Models,were discussed in details.And at last,the application perspectives of such models were illustrated,including animal movement,plant competition and landscape change.This study has relatively important significance guiding roles in developing Individual-based Spatial Explicit Landscape Model in our country and in landscape management.
