I have interdisciplinary interests in Environmental Informatics, Data Analytics, Applied Statistics, Risk Assessment, Population Biology, and Epidemiology. Address: http://arismoustakas.wixsite.com/mysite
Disease control strategies can have both intended and unintended effects on the dynamics of infec... more Disease control strategies can have both intended and unintended effects on the dynamics of infectious diseases. Routine testing for the harmful pathogen Bovine Tuberculosis (bTB) was suspended briefly during the foot and mouth disease epidemic of 2001 in Great Britain. Here we utilize bTB incidence data and mathematical models to demonstrate how a lapse in management can alter epidemiological parameters, including the rate of new infections and duration of infection cycles. Testing interruption shifted the dynamics from annual to 4-year cycles, and created long-lasting shifts in the spatial synchrony of new infections among regions of Great Britain. After annual testing was introduced in some GB regions, new infections have become more de-synchronised, a result also confirmed by a stochastic model. These results demonstrate that abrupt events can synchronise disease dynamics and that changes in the epidemiological parameters can lead to chaotic patterns, which are hard to be quanti...
Data-driven approaches may provide new insights into understanding facilitation. • Facilitation &... more Data-driven approaches may provide new insights into understanding facilitation. • Facilitation & competition coexist depending on the spatial scale. • Within a spatial scale there are competitive years and facilitative years. • Tree size is more important predictor than density in tree survival. • Large trees moderate surface temperature more than vegetation density.
Previous studies have shown that the response of bacterial communities to disturbances depends on... more Previous studies have shown that the response of bacterial communities to disturbances depends on their environmental history. Historically fluctuating habitats host communities that respond better to disturbance than communities of historically stable habitats. However, the exact ecological mechanism that drives this dependency remains unknown. Here, we experimentally demonstrate that modifications of niche optima and niche breadths of the community members are driving this dependency of bacterial responses to past environmental conditions. First, we develop a novel, simple method to calculate the niche optima and breadths of bacterial taxa regarding single environmental gradients. Then, we test this method on sediment bacterial communities of three habitats, one historically stable and less loaded and two historically more variable and more loaded habitats in terms of historical chlorophyll-a water concentration, that we subject to hypoxia via organic matter addition ex situ. We find that communities containing bacterial taxa differently adapted to hypoxia show different structural and functional responses, depending on the sediment's environmental history. Specifically, in the historically less fluctuating and loaded sediments where we find more taxa poorly adapted to hypoxic conditions, communities change a lot over time and organic matter is not degraded efficiently. The opposite is true for the historically more fluctuating and loaded sediments where we find more taxa well adapted to hypoxia. Based on the community responses observed here, we also propose an alternative calculation of community resistance that takes into account how rapidly the communities respond to disturbances and not just the initial and final states of the community.
The rapid increase of transportation infrastructure during the recent decades has caused a number... more The rapid increase of transportation infrastructure during the recent decades has caused a number of effects on bird species, including collision mortality, habitat loss, fragmentation and noise. This paper investigates the effects of traffic noise and road-induced fragmentation on breeding bird richness in Cyprus. Cyprus, situated along one of the main migratory routes for birds, has a rich and diverse avifauna threatened by an ever-expanding road network and a road density among the highest in Europe. In this first island-wide study we used data from 102 breeding birds recorded in 10 km × 10 km grid cells. Within every cell we calculated road traffic noise and eight road-related properties. Most of the grid cells are subject to intense fragmentation and traffic noise with combined impact 'hotspots' located even within protected areas (such as Cape Greco, and the Troodos Massif). Results from variance partitioning indicated that road-related properties (total road extent and road length) accounted for a combined 59% of variation in species richness, followed by fragmentation-related properties and noise properties. The study posits the need for further in-depth research on the effects of road networks on birds, and road construction, particularly in protected areas within Mediterranean islands. Key policy insights • Road areal extent is as important as road density when evaluating the effects of roads on biodiversity • In addition to roadless areas, conservation efforts should focus on areas with low combined impact of noise and fragmentation • Mitigation measures are required within protected areas where high noise and fragmentation are documented ARTICLE HISTORY
A paradox of impacting on biodiversity to combat climate change emerges. • Sustainable scenario: ... more A paradox of impacting on biodiversity to combat climate change emerges. • Sustainable scenario: locate windfarms in fragmented land outside protected areas. • The scenario hampers fragmentation and benefits biodiversity in Greece. • The scenario meets climate goals for 2030 and beyond. • Need for environmental policy towards the no net land take milestone.
Fire has been an integral part of the Earth for millennia. Several recent wildfires have exhibite... more Fire has been an integral part of the Earth for millennia. Several recent wildfires have exhibited an unprecedented spatial and temporal extent and their control is beyond national firefighting capabilities. Prescribed or controlled burning treatments are debated as a potential measure for ameliorating the spread and intensity of wildfires. Machine learning analysis using random forests was performed in a spatio-temporal data set comprising a large number of savanna fires across 22 years. Results indicate that fire return interval was not an important predictor of fire spread rate or fire intensity, having a feature importance of 3.5%, among eight other predictor variables. Manipulating burn seasonality showed a feature importance of 6% or less regarding fire spread rate or fire intensity. While manipulated fire return interval and seasonality moderated both fire spread rate and intensity, their overall effects were low in comparison with meteorological (hydrological and climatic) variables. The variables with the highest feature importance regarding fire spread rate resulted in fuel moisture with 21%, relative humidity with 15%, wind speed with 14%, and last years' rainfall with 14%. The variables with the highest feature importance regarding. Fire intensity included fuel load with 21.5%, fuel moisture with 16.5%, relative humidity with 12.5%, air temperature with 12.5%, and rainfall with 12.5%, Predicting fire spread rate and intensity has been a poor endeavour thus far and we show that more data of the variables already monitored would not result in higher predictive accuracy.
Disease spread is a complex phenomenon requiring an interdisciplinary approach. Covid-19 exhibite... more Disease spread is a complex phenomenon requiring an interdisciplinary approach. Covid-19 exhibited a global spatial spread in a very short time frame resulting in a global pandemic. Data of new Covid-19 cases per million were analysed worldwide at the spatial scale of a country and time replicated from the end of December 2019 to late May 2020. Data driven analysis of epidemiological, economic, public health, and governmental intervention variables was performed in order to select the optimal variables in explaining new Covid-19 cases across all countries in time. Sequentially, hierarchical variance partitioning of the optimal variables was performed in order to quantify the independent contribution of each variable in the total variance of new Covid-19 cases per million. Results indicated that from the variables available new tests per thousand explained the vast majority of the total variance in new cases (51.6%) followed by the governmental stringency index (15.2%). Availability ...
School of Science, Beijing University of Posts and Telecommunications, Beijing, China, Department... more School of Science, Beijing University of Posts and Telecommunications, Beijing, China, Department of Genetics, Faculty of Biology, University of Cambridge, Cambridge, United Kingdom, Center for OPTical IMagery Analysis and Learning (OPTIMAL), Northwestern Polytechnical University, Xi’an, China, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR China, Tianjin University of Technology, Tianjin, China, Natural History Museum of Crete, University of Crete, Heraklion, Greece, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York City, NY, United States
The savanna biome has the greatest burned area globally. Whereas the global distribution of most ... more The savanna biome has the greatest burned area globally. Whereas the global distribution of most biomes can be predicted successfully from climatic variables, this is not so for savannas. Attempts to dynamically model the distribution of savannas, including a realistically varying tree : grass ratio are fraught with difficulties. In a simulation study using the dynamic vegetation model LPJ-GUESS we investigate the effect of fire on the tree : grass ratios as well as the biome distribution on the African continent. We performed simulations at three spatial scales: locally, at four sites inside Kruger National Park (South Africa); regionally, along a precipitation gradient; and for the African continent. We evaluated the model using results of a fire experiment and found that the model underestimates the effect of fire on tree cover slightly. On a regional scale, high frequencies were able to prevent trees from outcompeting grasses in mesic regions between ~700 and 900 mm mean annual ...
Fire is an integral part of the Earth for millennia. Several recent wildfires have exhibited an u... more Fire is an integral part of the Earth for millennia. Several recent wildfires have exhibited an unprecedented spatial and temporal extent and their control is beyond national firefighting capabilities. Prescribed or controlled burning treatments are debated as a potential measure for ameliorating the spread and intensity of wildfires. Machine learning analysis using random forests was performed in a spatio-temporal data set comprising a large number of savanna fires across 22 years. Results indicate that controlled fire return interval exhibited a feature importance of 3.5% regarding fire spread rate and 3.5% regarding fire intensity. Manipulating burn seasonality showed a feature importance of 5% regarding fire spread rate and 6% regarding fire intensity. While manipulated fire return interval and seasonality moderated both fire spread rate and intensity, their overall effects were low in comparison with meteorological (hydrological and climatic) variables. Predicting fire spread r...
Stochastic Environmental Research and Risk Assessment, Dec 31, 2008
... 123 Stoch Environ Res Risk Assess (2009) 23:111118 DOI 10.1007/s00477-007-0199-x Page 2. ...... more ... 123 Stoch Environ Res Risk Assess (2009) 23:111118 DOI 10.1007/s00477-007-0199-x Page 2. ... The plots are non-adjacent and separated by distances 29 km. All plots are located in the Southern Kalahari, near the city of Kimberley in South Africa. ...
Disease control strategies can have both intended and unintended effects on the dynamics of infec... more Disease control strategies can have both intended and unintended effects on the dynamics of infectious diseases. Routine testing for the harmful pathogen Bovine Tuberculosis (bTB) was suspended briefly during the foot and mouth disease epidemic of 2001 in Great Britain. Here we utilize bTB incidence data and mathematical models to demonstrate how a lapse in management can alter epidemiological parameters, including the rate of new infections and duration of infection cycles. Testing interruption shifted the dynamics from annual to 4-year cycles, and created long-lasting shifts in the spatial synchrony of new infections among regions of Great Britain. After annual testing was introduced in some GB regions, new infections have become more de-synchronised, a result also confirmed by a stochastic model. These results demonstrate that abrupt events can synchronise disease dynamics and that changes in the epidemiological parameters can lead to chaotic patterns, which are hard to be quanti...
Data-driven approaches may provide new insights into understanding facilitation. • Facilitation &... more Data-driven approaches may provide new insights into understanding facilitation. • Facilitation & competition coexist depending on the spatial scale. • Within a spatial scale there are competitive years and facilitative years. • Tree size is more important predictor than density in tree survival. • Large trees moderate surface temperature more than vegetation density.
Previous studies have shown that the response of bacterial communities to disturbances depends on... more Previous studies have shown that the response of bacterial communities to disturbances depends on their environmental history. Historically fluctuating habitats host communities that respond better to disturbance than communities of historically stable habitats. However, the exact ecological mechanism that drives this dependency remains unknown. Here, we experimentally demonstrate that modifications of niche optima and niche breadths of the community members are driving this dependency of bacterial responses to past environmental conditions. First, we develop a novel, simple method to calculate the niche optima and breadths of bacterial taxa regarding single environmental gradients. Then, we test this method on sediment bacterial communities of three habitats, one historically stable and less loaded and two historically more variable and more loaded habitats in terms of historical chlorophyll-a water concentration, that we subject to hypoxia via organic matter addition ex situ. We find that communities containing bacterial taxa differently adapted to hypoxia show different structural and functional responses, depending on the sediment's environmental history. Specifically, in the historically less fluctuating and loaded sediments where we find more taxa poorly adapted to hypoxic conditions, communities change a lot over time and organic matter is not degraded efficiently. The opposite is true for the historically more fluctuating and loaded sediments where we find more taxa well adapted to hypoxia. Based on the community responses observed here, we also propose an alternative calculation of community resistance that takes into account how rapidly the communities respond to disturbances and not just the initial and final states of the community.
The rapid increase of transportation infrastructure during the recent decades has caused a number... more The rapid increase of transportation infrastructure during the recent decades has caused a number of effects on bird species, including collision mortality, habitat loss, fragmentation and noise. This paper investigates the effects of traffic noise and road-induced fragmentation on breeding bird richness in Cyprus. Cyprus, situated along one of the main migratory routes for birds, has a rich and diverse avifauna threatened by an ever-expanding road network and a road density among the highest in Europe. In this first island-wide study we used data from 102 breeding birds recorded in 10 km × 10 km grid cells. Within every cell we calculated road traffic noise and eight road-related properties. Most of the grid cells are subject to intense fragmentation and traffic noise with combined impact 'hotspots' located even within protected areas (such as Cape Greco, and the Troodos Massif). Results from variance partitioning indicated that road-related properties (total road extent and road length) accounted for a combined 59% of variation in species richness, followed by fragmentation-related properties and noise properties. The study posits the need for further in-depth research on the effects of road networks on birds, and road construction, particularly in protected areas within Mediterranean islands. Key policy insights • Road areal extent is as important as road density when evaluating the effects of roads on biodiversity • In addition to roadless areas, conservation efforts should focus on areas with low combined impact of noise and fragmentation • Mitigation measures are required within protected areas where high noise and fragmentation are documented ARTICLE HISTORY
A paradox of impacting on biodiversity to combat climate change emerges. • Sustainable scenario: ... more A paradox of impacting on biodiversity to combat climate change emerges. • Sustainable scenario: locate windfarms in fragmented land outside protected areas. • The scenario hampers fragmentation and benefits biodiversity in Greece. • The scenario meets climate goals for 2030 and beyond. • Need for environmental policy towards the no net land take milestone.
Fire has been an integral part of the Earth for millennia. Several recent wildfires have exhibite... more Fire has been an integral part of the Earth for millennia. Several recent wildfires have exhibited an unprecedented spatial and temporal extent and their control is beyond national firefighting capabilities. Prescribed or controlled burning treatments are debated as a potential measure for ameliorating the spread and intensity of wildfires. Machine learning analysis using random forests was performed in a spatio-temporal data set comprising a large number of savanna fires across 22 years. Results indicate that fire return interval was not an important predictor of fire spread rate or fire intensity, having a feature importance of 3.5%, among eight other predictor variables. Manipulating burn seasonality showed a feature importance of 6% or less regarding fire spread rate or fire intensity. While manipulated fire return interval and seasonality moderated both fire spread rate and intensity, their overall effects were low in comparison with meteorological (hydrological and climatic) variables. The variables with the highest feature importance regarding fire spread rate resulted in fuel moisture with 21%, relative humidity with 15%, wind speed with 14%, and last years' rainfall with 14%. The variables with the highest feature importance regarding. Fire intensity included fuel load with 21.5%, fuel moisture with 16.5%, relative humidity with 12.5%, air temperature with 12.5%, and rainfall with 12.5%, Predicting fire spread rate and intensity has been a poor endeavour thus far and we show that more data of the variables already monitored would not result in higher predictive accuracy.
Disease spread is a complex phenomenon requiring an interdisciplinary approach. Covid-19 exhibite... more Disease spread is a complex phenomenon requiring an interdisciplinary approach. Covid-19 exhibited a global spatial spread in a very short time frame resulting in a global pandemic. Data of new Covid-19 cases per million were analysed worldwide at the spatial scale of a country and time replicated from the end of December 2019 to late May 2020. Data driven analysis of epidemiological, economic, public health, and governmental intervention variables was performed in order to select the optimal variables in explaining new Covid-19 cases across all countries in time. Sequentially, hierarchical variance partitioning of the optimal variables was performed in order to quantify the independent contribution of each variable in the total variance of new Covid-19 cases per million. Results indicated that from the variables available new tests per thousand explained the vast majority of the total variance in new cases (51.6%) followed by the governmental stringency index (15.2%). Availability ...
School of Science, Beijing University of Posts and Telecommunications, Beijing, China, Department... more School of Science, Beijing University of Posts and Telecommunications, Beijing, China, Department of Genetics, Faculty of Biology, University of Cambridge, Cambridge, United Kingdom, Center for OPTical IMagery Analysis and Learning (OPTIMAL), Northwestern Polytechnical University, Xi’an, China, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR China, Tianjin University of Technology, Tianjin, China, Natural History Museum of Crete, University of Crete, Heraklion, Greece, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York City, NY, United States
The savanna biome has the greatest burned area globally. Whereas the global distribution of most ... more The savanna biome has the greatest burned area globally. Whereas the global distribution of most biomes can be predicted successfully from climatic variables, this is not so for savannas. Attempts to dynamically model the distribution of savannas, including a realistically varying tree : grass ratio are fraught with difficulties. In a simulation study using the dynamic vegetation model LPJ-GUESS we investigate the effect of fire on the tree : grass ratios as well as the biome distribution on the African continent. We performed simulations at three spatial scales: locally, at four sites inside Kruger National Park (South Africa); regionally, along a precipitation gradient; and for the African continent. We evaluated the model using results of a fire experiment and found that the model underestimates the effect of fire on tree cover slightly. On a regional scale, high frequencies were able to prevent trees from outcompeting grasses in mesic regions between ~700 and 900 mm mean annual ...
Fire is an integral part of the Earth for millennia. Several recent wildfires have exhibited an u... more Fire is an integral part of the Earth for millennia. Several recent wildfires have exhibited an unprecedented spatial and temporal extent and their control is beyond national firefighting capabilities. Prescribed or controlled burning treatments are debated as a potential measure for ameliorating the spread and intensity of wildfires. Machine learning analysis using random forests was performed in a spatio-temporal data set comprising a large number of savanna fires across 22 years. Results indicate that controlled fire return interval exhibited a feature importance of 3.5% regarding fire spread rate and 3.5% regarding fire intensity. Manipulating burn seasonality showed a feature importance of 5% regarding fire spread rate and 6% regarding fire intensity. While manipulated fire return interval and seasonality moderated both fire spread rate and intensity, their overall effects were low in comparison with meteorological (hydrological and climatic) variables. Predicting fire spread r...
Stochastic Environmental Research and Risk Assessment, Dec 31, 2008
... 123 Stoch Environ Res Risk Assess (2009) 23:111118 DOI 10.1007/s00477-007-0199-x Page 2. ...... more ... 123 Stoch Environ Res Risk Assess (2009) 23:111118 DOI 10.1007/s00477-007-0199-x Page 2. ... The plots are non-adjacent and separated by distances 29 km. All plots are located in the Southern Kalahari, near the city of Kimberley in South Africa. ...
Invasive alien species are non-indigenous taxa introduced to areas beyond their natural distribut... more Invasive alien species are non-indigenous taxa introduced to areas beyond their natural distribution and bio-geographical barriers by human activity, with important impacts on biodiversity, human health and ecosystem services. With the human population being higher than ever before and increasing, together with unprecedented rates of mobility of humans and goods, the introduction of new invasive species is more common than ever and is at the forefront of research in many disciplines such as ecology, epidemiology and food security. Data Mining Invasive Species The mechanisms of successful introduction, establishment and spread of invasive alien species are highly complex as biological, social, geographic, economic and climatic factors influence the way an invasive species is introduced and determine the options available for its eventual detection and control. With the rapid development of smart sensors, social networks, digital maps and remotely-sensed imagery, spatio-temporal data are more ubiquitous and richer than ever before. The availability of such large datasets (Big data) poses great challenges in data analysis. In addition, increased availability of computing power facilitates the use of computationally-intensive methods for the analysis of such data. Thus new methods are needed to efficiently study and understand biological invasions. A Research Topic held in Frontiers Environmental Informatics aimed to address this topic. Methods are defined in the widest terms and may be analytical, practical or conceptual. Among others, a key aim of the thematic was to maximize the use of the proposed methods/techniques by the scientific community and environmental stakeholders.
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Data Mining Invasive Species The mechanisms of successful introduction, establishment and spread of invasive alien species are highly complex as biological, social, geographic, economic and climatic factors influence the way an invasive species is introduced and determine the options available for its eventual detection and control.
With the rapid development of smart sensors, social networks, digital maps and remotely-sensed imagery, spatio-temporal data are more ubiquitous and richer than ever before. The availability of such large datasets (Big data) poses great challenges in data analysis. In addition, increased availability of computing power facilitates the use of computationally-intensive methods for the analysis of such data.
Thus new methods are needed to efficiently study and understand biological invasions. A Research Topic held in Frontiers Environmental Informatics aimed to address this topic. Methods are defined in the widest terms and may be analytical, practical or conceptual. Among others, a key aim of the thematic was to maximize the use of the proposed methods/techniques by the scientific community and environmental stakeholders.