Land use impacts on freshwater regulation, erosion regulation, and water purification: a spatial approach for a global scale level

Abstract Land-use change is one of the focal processes in Earth system models because it has strong impacts on terrestrial biogeophysical and biogeochemical conditions. However, modeling land-use impacts is still challenging because of model complexity and uncertainty. This study examined the results of simulations of land-use change impacts by the Model for Interdisciplinary Research on Climate, Earth System version 2 for long-term simulations (MIROC-ES2L) conducted under the Land-Use Model Intercomparison Project protocol. In a historical experiment, the model reproduced biogeophysical impacts such as decreasing trends in land-surface net radiation and evapotranspiration by about 1970. Among biogeochemical impacts, the model captured the global decrease of vegetation and soil carbon stocks caused by extensive deforestation. By releasing ecosystem carbon stock to the atmosphere, land-use change shortened the mean residence time of terrestrial carbon and accelerated its turnover rate, especially in low latitudes. Future projections based on Shared Socioeconomic Pathways indicated substantial alteration of land conditions caused primarily by climatic change and secondarily by land-use change. Sensitivity experiments conducted by exchanging land-use data between different future projection baseline experiments showed that, at the global scale, the anticipated extent of land-use conversion would likely play a modest role in the future terrestrial radiation, water, and carbon budgets. Regional investigations revealed that future land use would exert a considerable influence on runoff and vegetation carbon stock. Further model refinement is required to improve its capability to analyze its complicated terrestrial linkages or nexus (e.g., food, bioenergy, and carbon sequestration) to climate-change impacts.

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A PYTHON TOOL TO ESTIMATE LAND-USE IMPACTS ON GROUNDWATER NITRATE CONCENTRATIONS OBSERVED AT HIGH-CAPACITY PUMPING WELLS IN AN UNCONFINED GLACIAL AQUIFER

10.1130/abs/2020am-349317 ◽

2020 ◽

Author(s):

Stephanie Lynn DeVries ◽

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William Garrett Hooten ◽

William Garrett Hooten

Keyword(s):

Land Use ◽

High Capacity ◽

Land Use Impacts ◽

Pumping Wells ◽

Nitrate Concentrations

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An Integrated Economic, Environmental and Social Approach to Agricultural Land-Use Planning

Land ◽

10.3390/land10040364 ◽

2021 ◽

Vol 10 (4) ◽

pp. 364

Author(s):

Sahar Shahpari ◽

Janelle Allison ◽

Matthew Tom Harrison ◽

Roger Stanley

Keyword(s):

Land Use ◽

Land Use Planning ◽

Agricultural Land ◽

Commodity Prices ◽

Global Scale ◽

Agricultural Land Use ◽

Climate Type ◽

Crop Selection ◽

Regional Impacts ◽

Farmer Decision Making

Agricultural land-use change is a dynamic process that varies as a function of social, economic and environmental factors spanning from the local to the global scale. The cumulative regional impacts of these factors on land use adoption decisions by farmers are neither well accounted for nor reflected in agricultural land use planning. We present an innovative spatially explicit agent-based modelling approach (Crop GIS-ABM) that accounts for factors involved in farmer decision making on new irrigation adoption to enable land-use predictions and exploration. The model was designed using a participatory approach, capturing stakeholder insights in a conceptual model of farmer decisions. We demonstrate a case study of the factors influencing the uptake of new irrigation infrastructure and land use in Tasmania, Australia. The model demonstrates how irrigated land-use expansion promotes the diffusion of alternative crops in the region, as well as how coupled social, biophysical and environmental conditions play an important role in crop selection. Our study shows that agricultural land use reflected the evolution of multiple simultaneous interacting biophysical and socio-economic drivers, including soil and climate type, crop and commodity prices, and the accumulated effects of interactive decisions of farmers.

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Changing Land Use and Population Density Are Degrading Water Quality in the Lower Mekong Basin

Water ◽

10.3390/w13141948 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1948

Author(s):

Flavia Tromboni ◽

Thomas E. Dilts ◽

Sarah E. Null ◽

Sapana Lohani ◽

Peng Bun Ngor ◽

...

Keyword(s):

Water Quality ◽

Land Use ◽

Population Density ◽

Local Population ◽

Reference Conditions ◽

Mekong River ◽

Land Use Impacts ◽

Wet Season ◽

Mekong Basin ◽

Lower Mekong Basin

Establishing reference conditions in rivers is important to understand environmental change and protect ecosystem integrity. Ranked third globally for fish biodiversity, the Mekong River has the world’s largest inland fishery providing livelihoods, food security, and protein to the local population. It is therefore of paramount importance to maintain the water quality and biotic integrity of this ecosystem. We analyzed land use impacts on water quality constituents (TSS, TN, TP, DO, NO3−, NH4+, PO43−) in the Lower Mekong Basin. We then used a best-model regression approach with anthropogenic land-use as independent variables and water quality parameters as the dependent variables, to define reference conditions in the absence of human activities (corresponding to the intercept value). From 2000–2017, the population and the percentage of crop, rice, and plantation land cover increased, while there was a decrease in upland forest and flooded forest. Agriculture, urbanization, and population density were associated with decreasing water quality health in the Lower Mekong Basin. In several sites, Thailand and Laos had higher TN, NO3−, and NH4+ concentrations compared to reference conditions, while Cambodia had higher TP values than reference conditions, showing water quality degradation. TSS was higher than reference conditions in the dry season in Cambodia, but was lower than reference values in the wet season in Thailand and Laos. This study shows how deforestation from agriculture conversion and increasing urbanization pressure causes water quality decline in the Lower Mekong Basin, and provides a first characterization of reference water quality conditions for the Lower Mekong River and its tributaries.

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Mistletoes in a changing world: a premonition of a non-analog future?

Botany ◽

10.1139/cjb-2019-0195 ◽

2020 ◽

Vol 98 (9) ◽

pp. 479-488

Author(s):

Francisco E. Fontúrbel

Keyword(s):

Land Use ◽

Land Use Changes ◽

Biodiversity Loss ◽

Global Scale ◽

Ecological Interactions ◽

Human Disturbances ◽

Climate Change Effects ◽

Long Run ◽

Plant Animal Interactions ◽

Changing World

Mistletoes are a group of flowering plants that have developed a parasitic lifeform through complex eco-evolutionary processes. Despite being considered a pest, mistletoes represent a keystone forest resource and are involved in complex plant–plant and plant–animal interactions. Their parasitic lifeform and specialized ecological interactions make mistletoes an ideal model with which to understand the effects of anthropogenic disturbances in a changing world. The accelerated growth of the human population has altered all ecosystems on Earth, leading to biodiversity loss. Land-use changes (involving habitat loss, fragmentation, degradation, and transformation processes) can alter the ecological scenario for mistletoe by altering hosts, mutualists, and nutrient cycling. Those changes may have large consequences at the community level, changing the spatial structure of mistletoes, as well as interaction effectiveness, facilitation process, interaction disruption, and novel interactions with invasive species, leading to non-analog communities in the long run. Furthermore, climate change effects operate on a global scale, enhancing the effects of land-use changes. As temperatures increase, many species would alter their distribution and phenology, potentially causing spatial and temporal mismatches. But more critical is the fact that water stress is likely to disrupt key ecological interactions. Thus, mistletoes can provide valuable insights for what we can expect in the future, as a result of human disturbances.

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