Aims: Fascioliasisis a parasitic and zoonotic liver disease that reduces the health and productiv... more Aims: Fascioliasisis a parasitic and zoonotic liver disease that reduces the health and productivity of infected cattle and sheep. In recent years, an observed increase in the prevalence of the disease in Western Africa has been attributed to the changes in regional climatic conditions. This study aims to employ climate predictions to predict future seasonal infection risk in Sokoto State, Nigeria and provide a basis for targeted active disease monitoring to inform the need for control measures. Place and Duration of Study: Department of Geography, School of Science and Engineering, University of Leicester, between November 2014 and October 2018. Methodology: This study employs the Ollerenshaw index which is commonly used and was modified by Yilma and Malone (1999) to be more suitable for forecasting annual disease risk for Fasciola hepatica and Fasciola gigantica. Relationships of the annual F.gigantica infection risk between historic climate data from WorldClim for 1970-2000 and f...
Lowland peatland in East Anglia has been drained and used as highly productive Grade 1 agricultur... more Lowland peatland in East Anglia has been drained and used as highly productive Grade 1 agricultural land since the 17th century. Drainage of this large carbon (C) store that has accrued over thousands of years results in land surface subsidence and peat wastage. Prolonged exposure of C dense peat soils to oxygen through on-going agricultural management results in sustained emissions of carbon dioxide (CO₂) to the atmosphere. A nationally increasing population and the economic importance of horticultural produce, combined with international commitments to reducing C emissions, requires a better understanding of this system in order to maintain food production and mitigate emissions of CO. Three full years of eddy covariance CO₂ flux measurements were made over leek, lettuce and celery crops. The site functioned as a net source of CO₂ in all years. Fluxes and their variability are discussed with relevance to meteorological conditions and agricultural management practices.
Rapid ecological shifts such as the replacement of forest ecosystems by grasslands can be detecte... more Rapid ecological shifts such as the replacement of forest ecosystems by grasslands can be detected using remotely sensed reflectance data. In addition to detecting forest losses, a longer time series of reflectance data can provide information about the persistence of these shifts, or alternatively about ecosystem recovery. In addition to changes in the amount of reflected energy, ecological shifts can be detected from the timing of phenological events that may change as the result of the replacement of one plant functional type with another. Our ability to detect forest recovery from disturbance depends on the length of the remotely sensed data record in relation to the recovery signal. Monitoring ecosystem recovery often relies on some proxy for a fully recovered ecosystem, usually the signal from the period prior to disturbance or from an adjacent, undisturbed area. The requirement of a pre-disturbance signal means an even longer time series of data are needed, and finding nearby...
Drainage of UK lowland peatlands has been undertaken over the last 400 years in order to exploit ... more Drainage of UK lowland peatlands has been undertaken over the last 400 years in order to exploit the productivity of carbon (C) rich peat soils. Management practices are such that many hectares of drained peatland remain un-vegetated for large periods of the year leaving the peat exposed and vulnerable to erosion and transportation by wind action, in events locally known as ‘fen blows’. The impacts of management activity on peatland C budgets have received much attention in relation to losses of soil C in the form of carbon dioxide (CO₂), whereas transport of C through aeolian pathways has remained largely unquantified. Here, horizontal mass flux of C across an agricultural field is quantified over three years using Big Springs Number Eight (BSNE’s) dust samplers and co-located micrometeorological measurements. Relationships between windblown sediment yield and wind speed and near-surface soil moisture content are assessed in combination with the influences of agricultural land mana...
Whilst all ecosystems must obey the second law of thermodynamics, these physical bounds and contr... more Whilst all ecosystems must obey the second law of thermodynamics, these physical bounds and controls on ecosystem evolution and development are largely ignored across the ecohydrological literature. To unravel the importance of these underlying restraints on ecosystem form and function, and their power to inform our scientific understanding, we have calculated the entropy budget of a range of peat ecosystems. We hypothesize that less disturbed peatlands are ‘near equilibrium’ with respect to the second law of thermodynamics and thus respond to change by minimizing entropy production. This ‘near equilibrium’ state is best achieved by limiting evaporative losses. Alternatively, peatlands ‘far‐from‐equilibrium’ respond to a change in energy inputs by maximizing entropy production which is best achieved by increasing evapotranspiration. To test these alternatives this study examined the energy balance time series from seven peatlands across a disturbance gradient. We estimate the entropy budgets for each and determine how a change in net radiation (ΔRn) was transferred to a change in latent heat flux (ΔλE). The study showed that: (i) The transfer of net radiation to latent heat differed significantly between peatlands. One group transferred up to 64% of the change in net radiation to a change in latent heat flux, while the second transferred as little as 27%. (ii) Sites that transferred the most energy to latent heat flux were those that produced the greatest entropy. The study shows that an ecosystem could be ‘near equilibrium’ rather than ‘far from equilibrium’.
Lowland peatlands represent one of the most carbon-rich ecosystems in the UK. As a result of wide... more Lowland peatlands represent one of the most carbon-rich ecosystems in the UK. As a result of widespread habitat modification and drainage to support agriculture and peat extraction, they have been converted from natural carbon sinks into major carbon sources, and are now amongst the largest sources of greenhouse gas (GHG) emissions from the UK land-use sector. Despite this, they have previously received relatively little policy attention, and measures to reduce GHG emissions either through re-wetting and restoration or improved management of agricultural land remain at a relatively early stage. In part, this has stemmed from a lack of reliable measurements on the carbon and GHG balance of UK lowland peatlands. This project aimed to address this evidence gap via an unprecedented programme of consistent, multi year field measurements at a total of 15 lowland peatland sites in England and Wales, ranging from conservation managed ‘near-natural’ ecosystems to intensively managed agricult...
This paper reviews the currently available optical sensors, their limitations and opportunities f... more This paper reviews the currently available optical sensors, their limitations and opportunities for deployment at Eddy Covariance (EC) sites in Europe. This review is based on the results obtained from an online survey designed and disseminated by the Co-cooperation in Science and Technology (COST) Action ESO903-"Spectral Sampling Tools for Vegetation Biophysical Parameters and Flux Measurements in Europe" that provided a complete view on spectral sampling activities carried out within the different research teams in European countries. The results have highlighted that a wide variety of optical sensors are in use at flux sites across Europe, and responses further demonstrated that users were not always fully aware of the key issues underpinning repeatability and the reproducibility of their spectral measurements. The key findings of this survey point towards the need for greater awareness of the need for standardisation and development of a common protocol of optical samp...
Aims: Fascioliasisis a parasitic and zoonotic liver disease that reduces the health and productiv... more Aims: Fascioliasisis a parasitic and zoonotic liver disease that reduces the health and productivity of infected cattle and sheep. In recent years, an observed increase in the prevalence of the disease in Western Africa has been attributed to the changes in regional climatic conditions. This study aims to employ climate predictions to predict future seasonal infection risk in Sokoto State, Nigeria and provide a basis for targeted active disease monitoring to inform the need for control measures. Place and Duration of Study: Department of Geography, School of Science and Engineering, University of Leicester, between November 2014 and October 2018. Methodology: This study employs the Ollerenshaw index which is commonly used and was modified by Yilma and Malone (1999) to be more suitable for forecasting annual disease risk for Fasciola hepatica and Fasciola gigantica. Relationships of the annual F.gigantica infection risk between historic climate data from WorldClim for 1970-2000 and f...
Lowland peatland in East Anglia has been drained and used as highly productive Grade 1 agricultur... more Lowland peatland in East Anglia has been drained and used as highly productive Grade 1 agricultural land since the 17th century. Drainage of this large carbon (C) store that has accrued over thousands of years results in land surface subsidence and peat wastage. Prolonged exposure of C dense peat soils to oxygen through on-going agricultural management results in sustained emissions of carbon dioxide (CO₂) to the atmosphere. A nationally increasing population and the economic importance of horticultural produce, combined with international commitments to reducing C emissions, requires a better understanding of this system in order to maintain food production and mitigate emissions of CO. Three full years of eddy covariance CO₂ flux measurements were made over leek, lettuce and celery crops. The site functioned as a net source of CO₂ in all years. Fluxes and their variability are discussed with relevance to meteorological conditions and agricultural management practices.
Rapid ecological shifts such as the replacement of forest ecosystems by grasslands can be detecte... more Rapid ecological shifts such as the replacement of forest ecosystems by grasslands can be detected using remotely sensed reflectance data. In addition to detecting forest losses, a longer time series of reflectance data can provide information about the persistence of these shifts, or alternatively about ecosystem recovery. In addition to changes in the amount of reflected energy, ecological shifts can be detected from the timing of phenological events that may change as the result of the replacement of one plant functional type with another. Our ability to detect forest recovery from disturbance depends on the length of the remotely sensed data record in relation to the recovery signal. Monitoring ecosystem recovery often relies on some proxy for a fully recovered ecosystem, usually the signal from the period prior to disturbance or from an adjacent, undisturbed area. The requirement of a pre-disturbance signal means an even longer time series of data are needed, and finding nearby...
Drainage of UK lowland peatlands has been undertaken over the last 400 years in order to exploit ... more Drainage of UK lowland peatlands has been undertaken over the last 400 years in order to exploit the productivity of carbon (C) rich peat soils. Management practices are such that many hectares of drained peatland remain un-vegetated for large periods of the year leaving the peat exposed and vulnerable to erosion and transportation by wind action, in events locally known as ‘fen blows’. The impacts of management activity on peatland C budgets have received much attention in relation to losses of soil C in the form of carbon dioxide (CO₂), whereas transport of C through aeolian pathways has remained largely unquantified. Here, horizontal mass flux of C across an agricultural field is quantified over three years using Big Springs Number Eight (BSNE’s) dust samplers and co-located micrometeorological measurements. Relationships between windblown sediment yield and wind speed and near-surface soil moisture content are assessed in combination with the influences of agricultural land mana...
Whilst all ecosystems must obey the second law of thermodynamics, these physical bounds and contr... more Whilst all ecosystems must obey the second law of thermodynamics, these physical bounds and controls on ecosystem evolution and development are largely ignored across the ecohydrological literature. To unravel the importance of these underlying restraints on ecosystem form and function, and their power to inform our scientific understanding, we have calculated the entropy budget of a range of peat ecosystems. We hypothesize that less disturbed peatlands are ‘near equilibrium’ with respect to the second law of thermodynamics and thus respond to change by minimizing entropy production. This ‘near equilibrium’ state is best achieved by limiting evaporative losses. Alternatively, peatlands ‘far‐from‐equilibrium’ respond to a change in energy inputs by maximizing entropy production which is best achieved by increasing evapotranspiration. To test these alternatives this study examined the energy balance time series from seven peatlands across a disturbance gradient. We estimate the entropy budgets for each and determine how a change in net radiation (ΔRn) was transferred to a change in latent heat flux (ΔλE). The study showed that: (i) The transfer of net radiation to latent heat differed significantly between peatlands. One group transferred up to 64% of the change in net radiation to a change in latent heat flux, while the second transferred as little as 27%. (ii) Sites that transferred the most energy to latent heat flux were those that produced the greatest entropy. The study shows that an ecosystem could be ‘near equilibrium’ rather than ‘far from equilibrium’.
Lowland peatlands represent one of the most carbon-rich ecosystems in the UK. As a result of wide... more Lowland peatlands represent one of the most carbon-rich ecosystems in the UK. As a result of widespread habitat modification and drainage to support agriculture and peat extraction, they have been converted from natural carbon sinks into major carbon sources, and are now amongst the largest sources of greenhouse gas (GHG) emissions from the UK land-use sector. Despite this, they have previously received relatively little policy attention, and measures to reduce GHG emissions either through re-wetting and restoration or improved management of agricultural land remain at a relatively early stage. In part, this has stemmed from a lack of reliable measurements on the carbon and GHG balance of UK lowland peatlands. This project aimed to address this evidence gap via an unprecedented programme of consistent, multi year field measurements at a total of 15 lowland peatland sites in England and Wales, ranging from conservation managed ‘near-natural’ ecosystems to intensively managed agricult...
This paper reviews the currently available optical sensors, their limitations and opportunities f... more This paper reviews the currently available optical sensors, their limitations and opportunities for deployment at Eddy Covariance (EC) sites in Europe. This review is based on the results obtained from an online survey designed and disseminated by the Co-cooperation in Science and Technology (COST) Action ESO903-"Spectral Sampling Tools for Vegetation Biophysical Parameters and Flux Measurements in Europe" that provided a complete view on spectral sampling activities carried out within the different research teams in European countries. The results have highlighted that a wide variety of optical sensors are in use at flux sites across Europe, and responses further demonstrated that users were not always fully aware of the key issues underpinning repeatability and the reproducibility of their spectral measurements. The key findings of this survey point towards the need for greater awareness of the need for standardisation and development of a common protocol of optical samp...
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Papers by Jörg Kaduk