Alice M Milner | Royal Holloway, University of London (original) (raw)

Papers by Alice M Milner

Environmental Evidence, 2014

Assessment of the quality of studies is a critical component of evidence syntheses such as system... more Assessment of the quality of studies is a critical component of evidence syntheses such as systematic reviews (SRs) that are used to inform policy decisions. To reduce the potential for reviewer bias, and to ensure that the findings of SRs are transparent and reproducible, organisations such as the Cochrane Collaboration, the Campbell Collaboration, and the Collaboration for Environmental Evidence, recommend the use of formal quality assessment tools as opposed to informal expert judgment. However, there is a bewildering array of around 300 formal quality assessment tools that have been identified in the literature, and it has been demonstrated that the use of different tools for the assessment of the same studies can result in different estimates of quality, which can potentially reverse the conclusions of a SR. It is therefore important to consider carefully, the choice of quality assessment tool. We argue that quality assessment tools should: (1) have proven construct validity (i.e. the assessment criteria have demonstrable link with what they purport to measure), (2) facilitate inter-reviewer agreement, (3) be applicable across study designs, and (4) be quick and easy to use. Our aim was to examine current best practice for quality assessment in healthcare and investigate the extent to which these best practices could be useful for assessing the quality of environmental science studies. The feasibility of this transfer is demonstrated in a number of existing SRs on environmental topics. We propose that environmental practitioners should revise, test and adopt the best practice quality assessment tools used in healthcare as a recommended approach for application to environmental science. We provide pilot versions of quality assessment tools, modified from the best practice tools used in healthcare, for application on studies from environmental science.

By using ground penetrating radar (GPR) to 'map' subsurface patterns in peat physical properties,... more By using ground penetrating radar (GPR) to 'map' subsurface patterns in peat physical properties, we investigated the developmental history of meso-scale surface patterning of microforms within a raised bog. Common offset GPR measurements were obtained along a 45 m transect, at frequencies ranging from 100 to 900 MHz. We found that low frequency (central frequency < 240 MHz) GPR could not adequately represent the subsurface structures of the peatland because individual peat layers were too thin. However, more detailed high frequency measurements (central frequency ≥ 240 MHz) showed a striking pattern of subsurface reflections that dip consistently in a northern direction. The angle of these dipping reflectors is calculated using a semblance algorithm and was shown to average 3.9o between a depth of 1.0 and 2.5 m. These dipping reflectors may indicate down slope migration of surface microforms during the development of the peatland. Based on the estimated angle and the rate of peat accumulation, the average rate of down slope propagation of these surface microforms is calculated at 9.8 mm per year. Further survey work is required to establish whether the downslope migration is common across the peatland.

Environmental Sciences Europe, 2015

This article highlights eight common issues that limit the policy impact of environmental science... more This article highlights eight common issues that limit the policy impact of environmental science research. The article also discusses what environmental scientists can do to resolve these issues, including (1) optimising the directness of their study so that it examines similar processes/populations/environments/ecosystems to that of policy interest; (2) using the most powerful study design possible, to increase confidence in the identified causal mechanisms; (3) selecting a sufficient sample size, to reduce the chance of false positives/negatives and increase policy-makers' confidence in extrapolation of the findings; (4) minimizing the risk of bias through randomization of study units to treatment and control groups (reducing the risk of selection bias), blinding of study units and investigators (reducing the risk of performance and detection bias), following-up study units from enrolment to study completion (reducing the risk of attrition bias) and prospectively registering the study on a publically-available platform (reducing the risk of reporting and publication bias); (5) proving that statistical analyses meet test assumptions by reporting the results of statistical assumption checks, ideally publishing full datasets online in an open-access format; (6) publishing the research whether statistically significant or not, policy-makers are just as interested in the negative or insignificant results as they are in the positive results; (7) making the study easy to find and use, the title and abstract of an article are of high importance in determining whether articles are examined in detail or not and used to inform policy; (8) contributing towards systematic reviews on environmental topics, to provide policy-makers with comprehensive, reproducible and updateable syntheses of all the evidence on a given topic.

Newsletters on Stratigraphy, 2015

Since the first pollen analyses from core material in the 1960s, the limnotelmatic sequence of Te... more Since the first pollen analyses from core material in the 1960s, the limnotelmatic sequence of Tenaghi Philippon, located within the subsurface of the Drama Basin of NE Greece, has been recognized as an exceptional archive of terrestrial climate and ecosystem dynamics for the Quaternary in Europe. The polleniferous sequence covers the last ~1.35 Ma continuously, spanning at least 19 consecutive glacial-interglacial cycles. Analyses of Tenaghi Philippon as based on the drillcores from the 1960s were restricted to a millennial-scale resolution. Because the original cores have deteriorated, the archive's potential for analyzing abrupt (i. e., centennial-to decadal-scale) climate and ecosystem change has long remained unexplored. Therefore new drilling campaigns were carried out in 2005 and 2009 to recover the 0-60 m and 50-200 m depth intervals of the archive, respectively. The new cores (recovery: 97.8 and 99.0%, respectively) allow characterization of the evolution of abrupt climate and ecosystem variability across the full range of climatic P r e P u b A r t i c l e eschweizerbart_xxx J. Pross et al. 2 P r e P u b A r t i c l e eschweizerbart_xxx

Earth and Planetary Science Letters, 2013

ABSTRACT The influence of precession on the redistribution of insolation on the top of the atmosp... more ABSTRACT The influence of precession on the redistribution of insolation on the top of the atmosphere predicts that climate change in the low latitudes is out of phase between the hemispheres. We test this prediction by the most direct approach, the analysis of terrestrial climate records, as they provide direct information on regional changes in the atmosphere. A review of evidence from absolutely-dated climate records shows that precession drives an interhemispheric anti-phasing of monsoon intensity. Maxima of boreal monsoon intensity are opposed by minima of austral monsoon intensity and vice versa.

Journal of Quaternary Science, 2013

A new high-resolution Last Interglacial pollen record from the Tenaghi Philippon peatland, northe... more A new high-resolution Last Interglacial pollen record from the Tenaghi Philippon peatland, northeast Greece, documents variability in forest composition and cover, which we attribute to changes in temperature and moisture availability. The declining stage of the interglacial was marked by a stepwise decrease in temperate tree populations and culminated in the complete collapse of forest at the onset of the ensuing stadial. The coincidence of the onset of the stepwise declining trend with the increased prominence of North Atlantic ice-rafting events suggests that ecological thresholds in southern Europe were only crossed once ice rafting events intensified, and implies that changes in North Atlantic ocean circulation were an important contributing factor to the declining temperate forest cover in southern Europe. Our results provide evidence for intra-interglacial variability in the low mid latitudes and suggest a coupling between the high northern latitudes and the northeast Mediterranean during this interval.

Quaternary International, 2012

The mountains of Tasmania reach an elevation of 1600 m a.s.l. and hosted cirque, valley glaciers ... more The mountains of Tasmania reach an elevation of 1600 m a.s.l. and hosted cirque, valley glaciers and small ice caps during the last glacial maximum (LGM). Equilibrium line altitudes (ELAs) rise from west to east across Tasmania along a precipitation gradient. The Lake St Clair Valley lies near the middle of this gradient and hosted the largest glacier in Tasmania measuring approximately 27 km in length, supplied with ice from the Du Cane Range and the western side of the central Tasmanian ice cap. This large piedmont lobe has a maximum extent marked by a series of terminal moraines on the southern shoreline of Lake St Clair at Cynthia Bay. No late glacial events are known in Tasmania. However, recessional moraines occur at several locations up the Narcissus Valley towards the head of the Du Cane Range and within small cirques on Mount Olympus to the west of Lake St Clair. We present preliminary results for surface exposure dating at several locations in the Narcissus Valley to constrain the deglacial history and test the assumption of monotonous retreat. Former glacier extent and ELAs are reconstructed for the various ice extents. A glacier reconstruction and modelling method is applied, which enables former glacier dynamics to be derived. Temperatures in Tasmania were depressed by approximately 6 C during the LGM, and from this it is then possible to determine required palaeoprecipitation and seasonality to maintain glaciation at the site. We compare this climate to the present day and look at potential causes for early deglaciation in Tasmania.

Environmental Science & Policy, 2014

1] Using ground-penetrating radar (GPR) to map subsurface patterns in peat physical properties, w... more 1] Using ground-penetrating radar (GPR) to map subsurface patterns in peat physical properties, we investigated the developmental history of meso-scale surface patterning of microforms within a raised bog. Common offset GPR measurements were obtained along a 45-m transect, at frequencies ranging from 100 to 900 MHz. We found that low-frequency (central frequency < 240 MHz) GPR could not adequately represent the subsurface structures of the peatland because individual peat layers were too thin. However, more detailed high-frequency measurements (central frequency ≥ 240 MHz) showed a striking pattern of subsurface reflections that dip consistently in a northerly direction. The angle of these dipping reflectors is calculated using a semblance algorithm and was shown to average 3.9 between a depth of 1.0 and 2.5 m. These dipping reflectors may indicate downslope migration of surface microforms during the development of the peatland. Based on the estimated angle and the rate of peat accumulation, the average rate of downslope propagation of these surface microforms is calculated at 9.8 mm per year. Further survey work is required to establish whether the downslope migration is common across the peatland. (2012), Do peatland microforms move through time? Examining the developmental history of a patterned peatland using ground-penetrating radar,

This field expedition had three specific aims: 1) To procure sediment sequences from a number of ... more This field expedition had three specific aims: 1) To procure sediment sequences from a number of lakes in the Mývatnssveit region. This aim relates to an ongoing project to reconstruct vegetation history using pollen analysis, some results of which are already published . 2) To excavate a number of charcoal productions pits and take samples for radiocarbon dating, to establish the timing of woodland exploitation across the region. 3) To undertake experiments to produce charcoal using traditional Icelandic methods, to improve our ability to interpret the archaeological data from charcoal production pits.

Current evidence suggests that all of the major events in hominin evolution have occurred in East... more Current evidence suggests that all of the major events in hominin evolution have occurred in East Africa. Over the last two decades, there has been intensive work undertaken to understand African palaeoclimate and tectonics in order to put together a coherent picture of how the environment of East Africa has varied in the past. The landscape of East Africa has altered dramatically over the last 10 million years. It has changed from a relatively flat, homogenous region covered with mixed tropical forest, to a varied and heterogeneous environment, with mountains over 4 km high and vegetation ranging from desert to cloud forest. The progressive rifting of East Africa has also generated numerous lake basins, which are highly sensitive to changes in the local precipitation-evaporation regime. There is now evidence that the presence of precession-driven, ephemeral deep-water lakes in East Africa were concurrent with major events in hominin evolution. It seems the unusual geology and climate of East Africa created periods of highly variable local climate, which, it has been suggested could have driven hominin speciation, encephalisation and dispersal out of Africa. One example is the significant hominin speciation and brain expansion event at~1.8 Ma that seems to have been coeval with the occurrence of highly variable, extensive, deep-water lakes. This complex, climatically very variable setting inspired first the variability selection hypothesis, which was then the basis for the pulsed climate variability hypothesis. The newer of the two suggests that the long-term drying trend in East Africa was punctuated by episodes of short, alternating periods of extreme humidity and aridity. Both hypotheses, together with other key theories of climate-evolution linkages, are discussed in this paper. Though useful the actual evolution mechanisms, which led to early hominins are still unclear and continue to be debated. However, it is clear that an understanding of East African lakes and their palaeoclimate history is required to understand the context within which humans evolved and eventually left East Africa.

Environmental Evidence, 2014

Assessment of the quality of studies is a critical component of evidence syntheses such as system... more Assessment of the quality of studies is a critical component of evidence syntheses such as systematic reviews (SRs) that are used to inform policy decisions. To reduce the potential for reviewer bias, and to ensure that the findings of SRs are transparent and reproducible, organisations such as the Cochrane Collaboration, the Campbell Collaboration, and the Collaboration for Environmental Evidence, recommend the use of formal quality assessment tools as opposed to informal expert judgment. However, there is a bewildering array of around 300 formal quality assessment tools that have been identified in the literature, and it has been demonstrated that the use of different tools for the assessment of the same studies can result in different estimates of quality, which can potentially reverse the conclusions of a SR. It is therefore important to consider carefully, the choice of quality assessment tool. We argue that quality assessment tools should: (1) have proven construct validity (i.e. the assessment criteria have demonstrable link with what they purport to measure), (2) facilitate inter-reviewer agreement, (3) be applicable across study designs, and (4) be quick and easy to use. Our aim was to examine current best practice for quality assessment in healthcare and investigate the extent to which these best practices could be useful for assessing the quality of environmental science studies. The feasibility of this transfer is demonstrated in a number of existing SRs on environmental topics. We propose that environmental practitioners should revise, test and adopt the best practice quality assessment tools used in healthcare as a recommended approach for application to environmental science. We provide pilot versions of quality assessment tools, modified from the best practice tools used in healthcare, for application on studies from environmental science.

By using ground penetrating radar (GPR) to 'map' subsurface patterns in peat physical properties,... more By using ground penetrating radar (GPR) to 'map' subsurface patterns in peat physical properties, we investigated the developmental history of meso-scale surface patterning of microforms within a raised bog. Common offset GPR measurements were obtained along a 45 m transect, at frequencies ranging from 100 to 900 MHz. We found that low frequency (central frequency < 240 MHz) GPR could not adequately represent the subsurface structures of the peatland because individual peat layers were too thin. However, more detailed high frequency measurements (central frequency ≥ 240 MHz) showed a striking pattern of subsurface reflections that dip consistently in a northern direction. The angle of these dipping reflectors is calculated using a semblance algorithm and was shown to average 3.9o between a depth of 1.0 and 2.5 m. These dipping reflectors may indicate down slope migration of surface microforms during the development of the peatland. Based on the estimated angle and the rate of peat accumulation, the average rate of down slope propagation of these surface microforms is calculated at 9.8 mm per year. Further survey work is required to establish whether the downslope migration is common across the peatland.

Environmental Sciences Europe, 2015

This article highlights eight common issues that limit the policy impact of environmental science... more This article highlights eight common issues that limit the policy impact of environmental science research. The article also discusses what environmental scientists can do to resolve these issues, including (1) optimising the directness of their study so that it examines similar processes/populations/environments/ecosystems to that of policy interest; (2) using the most powerful study design possible, to increase confidence in the identified causal mechanisms; (3) selecting a sufficient sample size, to reduce the chance of false positives/negatives and increase policy-makers' confidence in extrapolation of the findings; (4) minimizing the risk of bias through randomization of study units to treatment and control groups (reducing the risk of selection bias), blinding of study units and investigators (reducing the risk of performance and detection bias), following-up study units from enrolment to study completion (reducing the risk of attrition bias) and prospectively registering the study on a publically-available platform (reducing the risk of reporting and publication bias); (5) proving that statistical analyses meet test assumptions by reporting the results of statistical assumption checks, ideally publishing full datasets online in an open-access format; (6) publishing the research whether statistically significant or not, policy-makers are just as interested in the negative or insignificant results as they are in the positive results; (7) making the study easy to find and use, the title and abstract of an article are of high importance in determining whether articles are examined in detail or not and used to inform policy; (8) contributing towards systematic reviews on environmental topics, to provide policy-makers with comprehensive, reproducible and updateable syntheses of all the evidence on a given topic.

Newsletters on Stratigraphy, 2015

Since the first pollen analyses from core material in the 1960s, the limnotelmatic sequence of Te... more Since the first pollen analyses from core material in the 1960s, the limnotelmatic sequence of Tenaghi Philippon, located within the subsurface of the Drama Basin of NE Greece, has been recognized as an exceptional archive of terrestrial climate and ecosystem dynamics for the Quaternary in Europe. The polleniferous sequence covers the last ~1.35 Ma continuously, spanning at least 19 consecutive glacial-interglacial cycles. Analyses of Tenaghi Philippon as based on the drillcores from the 1960s were restricted to a millennial-scale resolution. Because the original cores have deteriorated, the archive's potential for analyzing abrupt (i. e., centennial-to decadal-scale) climate and ecosystem change has long remained unexplored. Therefore new drilling campaigns were carried out in 2005 and 2009 to recover the 0-60 m and 50-200 m depth intervals of the archive, respectively. The new cores (recovery: 97.8 and 99.0%, respectively) allow characterization of the evolution of abrupt climate and ecosystem variability across the full range of climatic P r e P u b A r t i c l e eschweizerbart_xxx J. Pross et al. 2 P r e P u b A r t i c l e eschweizerbart_xxx

Earth and Planetary Science Letters, 2013

ABSTRACT The influence of precession on the redistribution of insolation on the top of the atmosp... more ABSTRACT The influence of precession on the redistribution of insolation on the top of the atmosphere predicts that climate change in the low latitudes is out of phase between the hemispheres. We test this prediction by the most direct approach, the analysis of terrestrial climate records, as they provide direct information on regional changes in the atmosphere. A review of evidence from absolutely-dated climate records shows that precession drives an interhemispheric anti-phasing of monsoon intensity. Maxima of boreal monsoon intensity are opposed by minima of austral monsoon intensity and vice versa.

Journal of Quaternary Science, 2013

A new high-resolution Last Interglacial pollen record from the Tenaghi Philippon peatland, northe... more A new high-resolution Last Interglacial pollen record from the Tenaghi Philippon peatland, northeast Greece, documents variability in forest composition and cover, which we attribute to changes in temperature and moisture availability. The declining stage of the interglacial was marked by a stepwise decrease in temperate tree populations and culminated in the complete collapse of forest at the onset of the ensuing stadial. The coincidence of the onset of the stepwise declining trend with the increased prominence of North Atlantic ice-rafting events suggests that ecological thresholds in southern Europe were only crossed once ice rafting events intensified, and implies that changes in North Atlantic ocean circulation were an important contributing factor to the declining temperate forest cover in southern Europe. Our results provide evidence for intra-interglacial variability in the low mid latitudes and suggest a coupling between the high northern latitudes and the northeast Mediterranean during this interval.

Quaternary International, 2012

The mountains of Tasmania reach an elevation of 1600 m a.s.l. and hosted cirque, valley glaciers ... more The mountains of Tasmania reach an elevation of 1600 m a.s.l. and hosted cirque, valley glaciers and small ice caps during the last glacial maximum (LGM). Equilibrium line altitudes (ELAs) rise from west to east across Tasmania along a precipitation gradient. The Lake St Clair Valley lies near the middle of this gradient and hosted the largest glacier in Tasmania measuring approximately 27 km in length, supplied with ice from the Du Cane Range and the western side of the central Tasmanian ice cap. This large piedmont lobe has a maximum extent marked by a series of terminal moraines on the southern shoreline of Lake St Clair at Cynthia Bay. No late glacial events are known in Tasmania. However, recessional moraines occur at several locations up the Narcissus Valley towards the head of the Du Cane Range and within small cirques on Mount Olympus to the west of Lake St Clair. We present preliminary results for surface exposure dating at several locations in the Narcissus Valley to constrain the deglacial history and test the assumption of monotonous retreat. Former glacier extent and ELAs are reconstructed for the various ice extents. A glacier reconstruction and modelling method is applied, which enables former glacier dynamics to be derived. Temperatures in Tasmania were depressed by approximately 6 C during the LGM, and from this it is then possible to determine required palaeoprecipitation and seasonality to maintain glaciation at the site. We compare this climate to the present day and look at potential causes for early deglaciation in Tasmania.

Environmental Science & Policy, 2014

1] Using ground-penetrating radar (GPR) to map subsurface patterns in peat physical properties, w... more 1] Using ground-penetrating radar (GPR) to map subsurface patterns in peat physical properties, we investigated the developmental history of meso-scale surface patterning of microforms within a raised bog. Common offset GPR measurements were obtained along a 45-m transect, at frequencies ranging from 100 to 900 MHz. We found that low-frequency (central frequency < 240 MHz) GPR could not adequately represent the subsurface structures of the peatland because individual peat layers were too thin. However, more detailed high-frequency measurements (central frequency ≥ 240 MHz) showed a striking pattern of subsurface reflections that dip consistently in a northerly direction. The angle of these dipping reflectors is calculated using a semblance algorithm and was shown to average 3.9 between a depth of 1.0 and 2.5 m. These dipping reflectors may indicate downslope migration of surface microforms during the development of the peatland. Based on the estimated angle and the rate of peat accumulation, the average rate of downslope propagation of these surface microforms is calculated at 9.8 mm per year. Further survey work is required to establish whether the downslope migration is common across the peatland. (2012), Do peatland microforms move through time? Examining the developmental history of a patterned peatland using ground-penetrating radar,

This field expedition had three specific aims: 1) To procure sediment sequences from a number of ... more This field expedition had three specific aims: 1) To procure sediment sequences from a number of lakes in the Mývatnssveit region. This aim relates to an ongoing project to reconstruct vegetation history using pollen analysis, some results of which are already published . 2) To excavate a number of charcoal productions pits and take samples for radiocarbon dating, to establish the timing of woodland exploitation across the region. 3) To undertake experiments to produce charcoal using traditional Icelandic methods, to improve our ability to interpret the archaeological data from charcoal production pits.

Current evidence suggests that all of the major events in hominin evolution have occurred in East... more Current evidence suggests that all of the major events in hominin evolution have occurred in East Africa. Over the last two decades, there has been intensive work undertaken to understand African palaeoclimate and tectonics in order to put together a coherent picture of how the environment of East Africa has varied in the past. The landscape of East Africa has altered dramatically over the last 10 million years. It has changed from a relatively flat, homogenous region covered with mixed tropical forest, to a varied and heterogeneous environment, with mountains over 4 km high and vegetation ranging from desert to cloud forest. The progressive rifting of East Africa has also generated numerous lake basins, which are highly sensitive to changes in the local precipitation-evaporation regime. There is now evidence that the presence of precession-driven, ephemeral deep-water lakes in East Africa were concurrent with major events in hominin evolution. It seems the unusual geology and climate of East Africa created periods of highly variable local climate, which, it has been suggested could have driven hominin speciation, encephalisation and dispersal out of Africa. One example is the significant hominin speciation and brain expansion event at~1.8 Ma that seems to have been coeval with the occurrence of highly variable, extensive, deep-water lakes. This complex, climatically very variable setting inspired first the variability selection hypothesis, which was then the basis for the pulsed climate variability hypothesis. The newer of the two suggests that the long-term drying trend in East Africa was punctuated by episodes of short, alternating periods of extreme humidity and aridity. Both hypotheses, together with other key theories of climate-evolution linkages, are discussed in this paper. Though useful the actual evolution mechanisms, which led to early hominins are still unclear and continue to be debated. However, it is clear that an understanding of East African lakes and their palaeoclimate history is required to understand the context within which humans evolved and eventually left East Africa.