The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Jan Seibert - One of the best experts on this subject based on the ideXlab platform.
-
riparian zone hydrology and soil water total organic carbon toc implications for spatial variability and upscaling of lateral riparian toc exports
Biogeosciences, 2012Co-Authors: Steve W Lyon, Thomas Grabs, Hjalmar Laudon, Kevin Bishop, Jan SeibertAbstract:Groundwater flowing from hillslopes through ri- parian (near-stream) soils often undergoes chemical transfor- mations that can substantially influence stream water chem- istry. We used Landscape Analysis to predict total organic carbon (TOC) concentration profiles and groundwater levels measured in the riparian zone (RZ) of a 67 km 2 catchment in Sweden. TOC exported laterally from 13 riparian soil profiles was then estimated based on the riparian flow-concentration integration model (RIM). Much of the observed spatial vari- ability of riparian TOC concentrations in this system could be predicted from groundwater levels and the topographic wetness index (TWI). Organic riparian peat soils in forested areas emerged as hotspots exporting large amounts of TOC. These TOC fluxes were subject to considerable temporal variations caused by a combination of variable flow condi- tions and changing soil water TOC concentrations. Mineral riparian gley soils, on the other hand, were related to rather small TOC export rates and were characterized by relatively time-invariant TOC concentration profiles. Organic and min- eral soils in RZs constitute a heterogeneous Landscape mo- saic that potentially controls much of the spatial variability of stream water TOC. We developed an empirical regression model based on the TWI to move beyond the plot scale and to predict spatially variable riparian TOC concentration profiles for RZs underlain by glacial till.
-
on the relationships between catchment scale and streamwater mean residence time
Hydrological Processes, 2003Co-Authors: Brian L Mcglynn, M K Stewart, Jeffrey J Mcdonnell, Jan SeibertAbstract:The relationship between streamwater mean residence time (MRT) and Landscape characteristics is poorly understood. We used tritium (3H) to define our MRT. We tested the hypothesis that baseflow water MRT increases with increasing absolute catchment size at the Maimai catchments. These catchments are simple hydrologic systems relative to many catchments around the world, with uniformly wet climatic conditions, little seasonality, uniform and nearly impermeable bedrock, steep short hillslopes, shallow soils, and well-characterized hillslope and catchment hydrology. As a result, this is a relatively simple system and an ideal location for new MRT-related hypothesis testing. Whilst hydrologists have used 3H to estimate water age since the 1960s nuclear testing spike, atmospheric 3H levels have now approached near background levels and are often complicated by contamination from the nuclear industry. We present results for 3H sampled from our set of nested catchments in nuclear-industry-free New Zealand. Because of high precision Analysis, near-natural atmospheric 3H levels, and well-characterized rainfall 3H inputs, we were able to estimate the age of young (i.e. less than 3 years old) waters. Our results showed no correlation between MRT and catchment size. However, MRT was correlated to the median sub-catchment size of the sampled watersheds, as shown by Landscape Analysis of catchment area accumulation patterns. These preliminary findings suggest that Landscape organization, rather than total area, is a first-order control on MRT and points the way forward for more detailed Analysis of how Landscape organization affects catchment runoff characteristics. Copyright © 2003 John Wiley & Sons, Ltd.
Thomas Grabs - One of the best experts on this subject based on the ideXlab platform.
-
riparian zone hydrology and soil water total organic carbon toc implications for spatial variability and upscaling of lateral riparian toc exports
Biogeosciences, 2012Co-Authors: Steve W Lyon, Thomas Grabs, Hjalmar Laudon, Kevin Bishop, Jan SeibertAbstract:Groundwater flowing from hillslopes through ri- parian (near-stream) soils often undergoes chemical transfor- mations that can substantially influence stream water chem- istry. We used Landscape Analysis to predict total organic carbon (TOC) concentration profiles and groundwater levels measured in the riparian zone (RZ) of a 67 km 2 catchment in Sweden. TOC exported laterally from 13 riparian soil profiles was then estimated based on the riparian flow-concentration integration model (RIM). Much of the observed spatial vari- ability of riparian TOC concentrations in this system could be predicted from groundwater levels and the topographic wetness index (TWI). Organic riparian peat soils in forested areas emerged as hotspots exporting large amounts of TOC. These TOC fluxes were subject to considerable temporal variations caused by a combination of variable flow condi- tions and changing soil water TOC concentrations. Mineral riparian gley soils, on the other hand, were related to rather small TOC export rates and were characterized by relatively time-invariant TOC concentration profiles. Organic and min- eral soils in RZs constitute a heterogeneous Landscape mo- saic that potentially controls much of the spatial variability of stream water TOC. We developed an empirical regression model based on the TWI to move beyond the plot scale and to predict spatially variable riparian TOC concentration profiles for RZs underlain by glacial till.
Ralf Seppelt - One of the best experts on this subject based on the ideXlab platform.
-
Analysis of pattern process interactions based on Landscape models overview general concepts and methodological issues
Ecological Modelling, 2006Co-Authors: Boris Schroder, Ralf SeppeltAbstract:Pattern–process Analysis is one of the main threads in Landscape ecological research. It aims at understanding the complex relationships between ecological processes and Landscape patterns, identifying the underlying mechanisms and deriving valid predictions for scenarios of Landscape change and its consequences. Today, various studies cope with these tasks through so called “Landscape modelling” approaches. They integrate different aspects of heterogeneous and dynamic Landscapes and model different driving forces, often using both statistical and process-oriented techniques. We identify two main approaches to deal with the Analysis of pattern–process interactions: the first starts with pattern detection, pattern description and pattern Analysis, the second with process description, simulation and pattern generation. Focussing on the interplay between these two approaches, Landscape Analysis and Landscape modelling will improve our understanding of pattern–process interactions. The comparison of simulated and observed pattern is a prerequisite for both approaches. Therefore, we identify a set of quantitative, robust, and reproducible methods for the Analysis of spatiotemporal patterns that is a starting point for a standard toolbox for ecologists as major future challenge and suggest necessary further methodological developments.
Kevin Bishop - One of the best experts on this subject based on the ideXlab platform.
-
riparian zone hydrology and soil water total organic carbon toc implications for spatial variability and upscaling of lateral riparian toc exports
Biogeosciences, 2012Co-Authors: Steve W Lyon, Thomas Grabs, Hjalmar Laudon, Kevin Bishop, Jan SeibertAbstract:Groundwater flowing from hillslopes through ri- parian (near-stream) soils often undergoes chemical transfor- mations that can substantially influence stream water chem- istry. We used Landscape Analysis to predict total organic carbon (TOC) concentration profiles and groundwater levels measured in the riparian zone (RZ) of a 67 km 2 catchment in Sweden. TOC exported laterally from 13 riparian soil profiles was then estimated based on the riparian flow-concentration integration model (RIM). Much of the observed spatial vari- ability of riparian TOC concentrations in this system could be predicted from groundwater levels and the topographic wetness index (TWI). Organic riparian peat soils in forested areas emerged as hotspots exporting large amounts of TOC. These TOC fluxes were subject to considerable temporal variations caused by a combination of variable flow condi- tions and changing soil water TOC concentrations. Mineral riparian gley soils, on the other hand, were related to rather small TOC export rates and were characterized by relatively time-invariant TOC concentration profiles. Organic and min- eral soils in RZs constitute a heterogeneous Landscape mo- saic that potentially controls much of the spatial variability of stream water TOC. We developed an empirical regression model based on the TWI to move beyond the plot scale and to predict spatially variable riparian TOC concentration profiles for RZs underlain by glacial till.
Adnan A Hezri - One of the best experts on this subject based on the ideXlab platform.
-
From forest Landscape to agricultural Landscape in the developing tropical country of Malaysia: Pattern, process, and their significance on policy
Environmental Management, 2008Co-Authors: Saiful Arif Abdullah, Adnan A HezriAbstract:Agricultural expansion and deforestation are spatial processes of land transformation that impact on Landscape pattern. In peninsular Malaysia, the conversion of forested areas into two major cash crops--rubber and oil palm plantations--has been identified as driving significant environmental change. To date, there has been insufficient literature studying the link between changes in Landscape patterns and land-related development policies. Therefore, this paper examines: (i) the links between development policies and changes in land use/land cover and Landscape pattern and (ii) the significance and implications of these links for future development policies. The objective is to generate insights on the changing process of land use/land cover and Landscape pattern as a functional response to development policies and their consequences for environmental conditions. Over the last century, the development of cash crops has changed the country from one dominated by natural Landscapes to one dominated by agricultural Landscapes. But the last decade of the century saw urbanization beginning to impact significantly. This process aligned with the establishment of various development policies, from land development for agriculture between the mid 1950s and the 1970s to an emphasis on manufacturing from the 1980s onward. Based on a case study in Selangor, peninsular Malaysia, a model of Landscape pattern change is presented. It contains three stages according to the relative importance of rubber (first stage: 1900--1950s), oil palm (second stage: 1960s--1970s), and urban (third stage: 1980s--1990s) development that influenced Landscape fragmentation and heterogeneity. The environmental consequences of this change have been depicted through loss of biodiversity, geohazard incidences, and the spread of vector-borne diseases. The spatial ecological information can be useful to development policy formulation, allowing diagnosis of the country's "health" and sustainability. The final section outlines the usefulness of Landscape Analysis in the policy-making process to prevent further fragmentation of the Landscape and forest loss in Malaysia in the face of rapid economic development.
