Assessment of the risk of malaria re-introduction in the Maremma plain (Central Italy) using a mu... more Assessment of the risk of malaria re-introduction in the Maremma plain (Central Italy) using a multi-factorial approach
Abstract Recent investigations have supported the possibility of predicting soil water content (S... more Abstract Recent investigations have supported the possibility of predicting soil water content (SWC) through a simplified soil water balance (WB) model fed with remotely sensed actual evapotranspiration (ETa) estimates. This approach, however, requires information on main soil features (i.e. depth, wilting point, field capacity) which are generally difficult to retrieve over large regions. The current paper proposes an alternative model which directly predicts SWC relying on the same logic of the recently proposed ETa estimation method, i.e. the combination of meteorological and normalized difference vegetation index (NDVI) datasets. The theoretical bases of the old and new SWC estimation methods are first described. Both methods are then applied in Central Italy using ancillary and Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI data having a spatial resolution of 250 m; the outputs obtained are assessed versus SWC measurements taken both continuously and instantaneously. In the former case three ecosystems are analyzed (i.e. the grassland of Amplero and the forests of Barbialla and Amiata), where SWC was measured by probes during three different years (2003, 2012 and 2018, respectively). The latter experiment concerns 362 sample sites where SWC gravimetric measurements were taken during a similar time span (2000–2018). In both cases SWC is first normalized into relative SWC (RSWC), which is more directly influential on vegetation conditions. The results of both experiments indicate that the two simulation methods perform similarly when the former is driven by adequate information on soil features. The main limitations of the two simulation approaches are due to the spatial resolution mismatch between SWC measurements and estimates, which has a relatively minor impact on the first three homogeneous areas but is decisive for the other sampled sites. In general, the new simulation method is capable of predicting RSWC with relatively high spatial and temporal resolution without the use of specific soil information.
Assessment of the risk of malaria re-introduction in the Maremma plain (Central Italy) using a mu... more Assessment of the risk of malaria re-introduction in the Maremma plain (Central Italy) using a multi-factorial approach
ABSTRACT Drought is a recurrent feature of climate and can affect areas with different climate re... more ABSTRACT Drought is a recurrent feature of climate and can affect areas with different climate regimes and human activities. Its impacts depend on the duration, intensity and extent of precipitation deficiency and water demand for several purposes. Due to the complexity of this phenomenon, it is crucial to analyze both current conditions and evolution of a drought event in order to provide accurate, timely and affordable support for policy setting and impacts management. In this perspective the LaMMA Consortium and the IBIMET-CNR Institute are developing a comprehensive operational tool for quasi-real time drought monitoring and medium-long time forecasts in the Tuscany region (Central Italy), with the aim to deliver periodical, geo-referenced information about areas affected by an increasing reduction of available water resources. A coupled rainfall based and satellite derived monitoring system consists of a set of indices suitable for our region and selected taking into account data availability. This system allows the assessment of vegetation moisture and temperature conditions at different spatio-temporal scales. An analysis of vegetation performances related to temperature and moisture stress is made throughout Normalized Difference Vegetation Index (NDVI) anomalies and Vegetation Health Index (VHI), derived from the Terra-Moderate Resolution Imaging Spectroradiometer (MODIS) products, available since 2000 and updated each 16 days. These indices are selected in order to enhance the climate-based Standardized Precipitation Index (SPI) and Effective Drought Index (EDI), which provide multiple time scale drought occurrence and duration. Moreover, multi-temporal NDVI profiles of main Tuscan cultivations are used to monitor variations of seasonal growth in order to forecast possible crop yield reductions due to prolonged drought conditions. Data of SPI and EDI elaborated from long time series, starting from 1960, of a single rain gauge station or gridded over the whole region provide the base for seasonal outlooks of drought evolution. Forecasts of the next 1-3 months follow a physically-based statistical approach based on an “adaptive multi-regressive method” that takes into account potential predictors among a list of physical atmospheric indices and Sea Surface Temperature (SST) anomalies. Information about current condition related to the last 16 days available is delivered on the Consortium web site and uploaded on a WebGIS platform. Finally, monthly bulletins furnish a more detailed description of drought evolution throughout an analysis of the indices in the last 30 days and a forecast of the next 3 months. This comprehensive framework, composed by the monitoring and forecast systems, can become a timely and stand-alone multi-purpose tool for several final users, potentially able to give information useful for managing drought-related emergencies as crop yields losses, forest fires and water resources reduction.
The Maremma Plain (central Italy) was hyper-endemic for malaria until the mid-20th century, when ... more The Maremma Plain (central Italy) was hyper-endemic for malaria until the mid-20th century, when a national campaign for malaria elimination drastically reduced the presence of the main vector Anopheles labranchiae Falleroni. However, the introduction of rice cultivation over 30 yr ago has led to an increase in the An. labranchiae population and concern over possible malaria reemergence. We studied the impact of anthropogenic environmental changes on the abundance and distribution of An. labranchiae in Maremma, focusing on rice fields, the main breeding sites. Adults and larvae were collected in three main areas with diverse ecological characteristics. Data were collected on human activity, land use, and seasonal climatic and demographic variations. We also interviewed residents and tourists regarding their knowledge of malaria. Our findings showed that the most important environmental changes have occurred along the coast; An. labranchiae foci are present throughout the area, with massive reproduction strictly related to rice cultivation in coastal areas. Although the abundance of this species has drastically decreased over the past 30 yr, it remains high and, together with climatic conditions and the potential introduction of gametocyte carriers, it may represent a threat for the occurrence of autochthonous malaria cases. Our findings suggest the need for the continuous monitoring of An. labranchiae in the study area. In addition to entomological surveillance, more detailed knowledge of human-induced environmental changes is needed, so as to have a more complete database that can be used for vector-control plans and for properly managing emergencies related to autochthonous introduced cases.
Assessment of the risk of malaria re-introduction in the Maremma plain (Central Italy) using a mu... more Assessment of the risk of malaria re-introduction in the Maremma plain (Central Italy) using a multi-factorial approach
Abstract Recent investigations have supported the possibility of predicting soil water content (S... more Abstract Recent investigations have supported the possibility of predicting soil water content (SWC) through a simplified soil water balance (WB) model fed with remotely sensed actual evapotranspiration (ETa) estimates. This approach, however, requires information on main soil features (i.e. depth, wilting point, field capacity) which are generally difficult to retrieve over large regions. The current paper proposes an alternative model which directly predicts SWC relying on the same logic of the recently proposed ETa estimation method, i.e. the combination of meteorological and normalized difference vegetation index (NDVI) datasets. The theoretical bases of the old and new SWC estimation methods are first described. Both methods are then applied in Central Italy using ancillary and Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI data having a spatial resolution of 250 m; the outputs obtained are assessed versus SWC measurements taken both continuously and instantaneously. In the former case three ecosystems are analyzed (i.e. the grassland of Amplero and the forests of Barbialla and Amiata), where SWC was measured by probes during three different years (2003, 2012 and 2018, respectively). The latter experiment concerns 362 sample sites where SWC gravimetric measurements were taken during a similar time span (2000–2018). In both cases SWC is first normalized into relative SWC (RSWC), which is more directly influential on vegetation conditions. The results of both experiments indicate that the two simulation methods perform similarly when the former is driven by adequate information on soil features. The main limitations of the two simulation approaches are due to the spatial resolution mismatch between SWC measurements and estimates, which has a relatively minor impact on the first three homogeneous areas but is decisive for the other sampled sites. In general, the new simulation method is capable of predicting RSWC with relatively high spatial and temporal resolution without the use of specific soil information.
Assessment of the risk of malaria re-introduction in the Maremma plain (Central Italy) using a mu... more Assessment of the risk of malaria re-introduction in the Maremma plain (Central Italy) using a multi-factorial approach
ABSTRACT Drought is a recurrent feature of climate and can affect areas with different climate re... more ABSTRACT Drought is a recurrent feature of climate and can affect areas with different climate regimes and human activities. Its impacts depend on the duration, intensity and extent of precipitation deficiency and water demand for several purposes. Due to the complexity of this phenomenon, it is crucial to analyze both current conditions and evolution of a drought event in order to provide accurate, timely and affordable support for policy setting and impacts management. In this perspective the LaMMA Consortium and the IBIMET-CNR Institute are developing a comprehensive operational tool for quasi-real time drought monitoring and medium-long time forecasts in the Tuscany region (Central Italy), with the aim to deliver periodical, geo-referenced information about areas affected by an increasing reduction of available water resources. A coupled rainfall based and satellite derived monitoring system consists of a set of indices suitable for our region and selected taking into account data availability. This system allows the assessment of vegetation moisture and temperature conditions at different spatio-temporal scales. An analysis of vegetation performances related to temperature and moisture stress is made throughout Normalized Difference Vegetation Index (NDVI) anomalies and Vegetation Health Index (VHI), derived from the Terra-Moderate Resolution Imaging Spectroradiometer (MODIS) products, available since 2000 and updated each 16 days. These indices are selected in order to enhance the climate-based Standardized Precipitation Index (SPI) and Effective Drought Index (EDI), which provide multiple time scale drought occurrence and duration. Moreover, multi-temporal NDVI profiles of main Tuscan cultivations are used to monitor variations of seasonal growth in order to forecast possible crop yield reductions due to prolonged drought conditions. Data of SPI and EDI elaborated from long time series, starting from 1960, of a single rain gauge station or gridded over the whole region provide the base for seasonal outlooks of drought evolution. Forecasts of the next 1-3 months follow a physically-based statistical approach based on an “adaptive multi-regressive method” that takes into account potential predictors among a list of physical atmospheric indices and Sea Surface Temperature (SST) anomalies. Information about current condition related to the last 16 days available is delivered on the Consortium web site and uploaded on a WebGIS platform. Finally, monthly bulletins furnish a more detailed description of drought evolution throughout an analysis of the indices in the last 30 days and a forecast of the next 3 months. This comprehensive framework, composed by the monitoring and forecast systems, can become a timely and stand-alone multi-purpose tool for several final users, potentially able to give information useful for managing drought-related emergencies as crop yields losses, forest fires and water resources reduction.
The Maremma Plain (central Italy) was hyper-endemic for malaria until the mid-20th century, when ... more The Maremma Plain (central Italy) was hyper-endemic for malaria until the mid-20th century, when a national campaign for malaria elimination drastically reduced the presence of the main vector Anopheles labranchiae Falleroni. However, the introduction of rice cultivation over 30 yr ago has led to an increase in the An. labranchiae population and concern over possible malaria reemergence. We studied the impact of anthropogenic environmental changes on the abundance and distribution of An. labranchiae in Maremma, focusing on rice fields, the main breeding sites. Adults and larvae were collected in three main areas with diverse ecological characteristics. Data were collected on human activity, land use, and seasonal climatic and demographic variations. We also interviewed residents and tourists regarding their knowledge of malaria. Our findings showed that the most important environmental changes have occurred along the coast; An. labranchiae foci are present throughout the area, with massive reproduction strictly related to rice cultivation in coastal areas. Although the abundance of this species has drastically decreased over the past 30 yr, it remains high and, together with climatic conditions and the potential introduction of gametocyte carriers, it may represent a threat for the occurrence of autochthonous malaria cases. Our findings suggest the need for the continuous monitoring of An. labranchiae in the study area. In addition to entomological surveillance, more detailed knowledge of human-induced environmental changes is needed, so as to have a more complete database that can be used for vector-control plans and for properly managing emergencies related to autochthonous introduced cases.
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