Histories of bioinvasions in the Mediterranean

Dr Simon Pooley, Lambert Lecturer in Environment (Applied Herpetology) at Birkbeck discusses ‘bioinvasions’  – the phenomenon of plants, animals and microbes being introduced more frequently into new regions – which is the subject of his new book, co-edited with Ana Isabel Queiroz.

Bioinvasions, a global environmental problem of anthropogenic origin, have been studied mainly by the natural sciences. However, it is widely acknowledged that it is also important to understand the human dimensions of bioinvasions. The book brings together environmental historians and natural scientists to produce historical narratives of bioinvasions, drawing on a bricolage of sources and methods. Central to our endeavours is our recognition that temporal and spatial scales are crucial variables in all narratives which attempt to explain the movement of invasive species across ecosystems and landscapes.

This book has three overarching aims: first, to provoke natural scientists working on bioinvasions to think more historically; second, to convince environmental historians to engage with the science of bioinvasions; and third, through sharing the research presented in this book, to convince them all of the richness of the research materials and themes and the importance of the issues, and so stimulate interdisciplinary collaborations on bioinvasions.

So, why focus on the Mediterranean region? Primarily, it is because of the antiquity of human and ecological relations in the region, notably regional (and from the fifteenth century, global) maritime communications and trade. While historians have studied the impacts of European trade and invasive plants, animals and diseases elsewhere on the planet, they have paid less attention to the reverse flow. The introductions of some well-known naturalised (non-invasive) plants such as tomatoes, potatoes, tobacco and citrus, are better known.

Of course, as the eminent environmental historian J. Donald Hughes has remarked, the Mediterranean region is a somewhat fuzzy concept, and has been defined differently depending on whether scholars have chosen biophysical, political or cultural variables and definitions. In our usage, it includes the entirety of the Mediterranean Sea, and terrestrially, the Mediterranean-type climate (MTC) region surrounding this sea.

This biophysical framework should not obscure how this region has been transformed by human actions—from agriculture to herding, burning to hunting and deforestation. Such is the scale and diversity of such influences, over millennia, that the region represents an archetypal landscape where humans and their physical and biotic environments have coevolved.

Our book includes historical case studies which collectively contribute towards a history of bioinvasions in the Mediterranean region. The histories of marine invasions best fit this aspiration, in taking in the full sweep of the Mediterranean Sea. Some of the remaining chapters are perhaps more histories in than of the region, but they all offer insights into the histories and processes of invasion in the region which share commonalities across a diversity of ecological and cultural contexts. In addition to climatic and topographical factors, and longer-term geological processes, these include: seaborne exploration, colonisation, communication and trade; the impacts of agriculture, forestry and pastoralism; and the convergent evolution of the flora in response to human disturbances, notably land clearing and burning.

Histories of bioinvasions undermine notions of timeless continuities or geographical or environmental determinism. They feature an array of introduced species from across the globe’s oceans and shores, following diverse invasion pathways facilitated by unexpected vectors, imported for numerous purposes (or accidentally). Just possibly, in aggregate, bioinvasions herald a terminal disruption of the ecological coherence used to define a ‘Mediterranean basin’ region. So, this book offers both an argument for thinking in terms of a Mediterranean region, and offers a warning of its fragility, conceptually and physically.

Our book features nine case studies of bioinvasions from the plant and animal kingdoms, encompassing marine, freshwater and terrestrial environments. These include an overview of all marine bioinvasions, a chapter focussing on invasive marine and freshwater decapods (crayfish, crabs and prawns), terrestrial invasions by Argentine ants and waxbills, invasions of islands by reptiles, amphibians and Australian plants, invasions of coastal salt marshes by cord grasses, and of freshwater waterways by African clawed frogs. These invasive species have been transported from around the globe or internally within the Mediterranean region. My own chapter includes a section on the important role of fire coupled with invasive introduced plants in Mediterranean ecosystems. It also adds a comparative look at South Africa’s Mediterranean climate region, and the history of invasions of its unique fynbos biome, examining the reasons for introductions, and cultural, political and scientific responses to their social and environmental impacts. The chronological range of this collection extends from the Neolithic and the Bronze Ages through Classical times, the ages of European maritime discovery, to the present.

Ana Isabel Queiroz (NOVA-FCSH, Lisbon) and I (the editors) are grateful for the enthusiasm and patience of the scientists among our contributors in working through many exchanges and versions to steer their work towards more historical writing. The material reads unevenly as history, in parts, but we feel the gains are substantial. In the course of editing this book, we have noted some interesting gaps in historical knowledge. For example, our knowledge of the chronology of introductions and spread of species prior to the twentieth century is surprisingly imprecise. Awareness of most of these invasions has come surprisingly late, with most discoveries and interventions described here occurring in the late twentieth or early twenty-first centuries.

In our Introduction to the book, Ana and I highlight promising avenues for further research by environmental historians. For instance, too little is known about some major pathways of invasion (notably maritime) into Mediterranean Europe, and historians have paid scant attention to invasions from species moved around within the region. There is interesting work to be done on the role of empires and their collapses, and resulting movements of humans and biota, in the introduction of invasive species. Comparative histories of management interventions and their outcomes could provide important contextual information for attempts to control bioinvasions in the region. It seems that shrubs of the region survive or recover from anthropogenic disturbances, and on the whole resist invasions by plants introduced from the other Mediterranean climate regions, possibly (as ecologist Jon Keeley has argued) because of the long history of coevolution of humans with the local biota. An exception is the western Iberian region, and it would be useful to have environmental histories of the introduction and spread of Australian trees and shrubs in this region. Finally, there are fascinating opportunities to synthesise histories of the colonisation of the region by the terrestrial fauna after humans arrived on the scene.

Histories of Bioinvasions in the Mediterranean ed. Ana Isabel Queiroz and Simon Pooley, is available now from Springer.

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Birkbeck’s BabyLab: Investigating neural underpinnings of the social brain

Anna Kolesnik, PhD candidate in Birkbeck’s Centre for Brain and Cognitive Development (CBCD) discusses the research in motion at the BabyLab, and why we’re crowdfunding to extend this research to toddlers.

How do babies become experts at processing the social world? Can we identify early neural correlates of this specialisation?

Previous investigations carried out at the BabyLab have explored rhythmic activity in the brain in response to social stimuli, finding evidence for early specialisation to faces and gaze as early as 4 months of age. Throughout the second half of the first year, we have seen evidence for increased perceptual narrowing in several aspects of cognition, allowing more efficient processing of incoming information. We also know that by age 2-3 years, toddlers become experts at navigating the social world and tune their attention to relevant information sources. This is also the time where first behavioural symptoms of neurodevelopmental disorders such as Autism emerge. Majority of our current understanding comes from cross-sectional research, which captures a ‘snap-shot’ in development. Here at the BabyLab, we want to study the early years continuously, which will increase our ability to identify and propose intervention strategies for infants at risk.  

GAmma and Brain-Based LanguagE Specialization study (GABBLES)
As part of my PhD project, I am running a longitudinal study with typically developing infants which aims to understand the neural basis of auditory and intercessory processing in the first year of life by examining changes in rhythmic neural activity in the brain. Using the predictions set out by Professor Mark Johnson’s ‘Interactive Specialisation’ framework, one of the leading theories of development in the field, we hope to isolate the fundamental sensory processes which precede the infants’ first words

Families with 5-month-old infants were recruited to take part in the study at the BabyLab in the Centre for Brain and Cognitive Development, with additional visits at 10 and 14 months. Fourteen babies form a subgroup of bilinguals, as they are exposed to a language other than English for a significant time. The testing protocol included tasks to evoke oscillatory activity in auditory and visual areas of the brain (which we record from passive sensors placed on the baby’s head). They also completed an eye-tracking session, which measured several aspects of pre-verbal language development and comprehension– including word recognition, language preference, and syllable matching tasks. These were accompanied by a standardised assessment of the infant’s cognitive and motor abilities. After the three visits were complete, parents were asked to complete questionnaires on their child’s behaviour, language and sleep until their children turn 2 years. Currently, data collection is almost complete and our lovely participants are entering toddlerhood.

Future directions
At present time, we are only able to collect parent-report questionnaires about language and social abilities of their toddlers. In some ways, this is useful as we can capture some individual differences in development on a behavioural level (i.e. language experience and vocabulary), and then go back and look at possible biomarkers (activation to a native vowel or attention to native/non-native speakers). Being able to follow up these children using wireless technology once they are verbal and actively engaging with the outside world would provide enormously rich insight into how our early brain specialisation affects later functional development. Further, we may be able to identify critical periods of maturation and change in order to generate the most effective interventions and improve outcomes in children with autism.

We are aiming to secure £30,000 in donations for the equipment for the new ToddlerLab. If you are interested in donating and contributing to the centre’s crucial research into children’s development, please see our crowdfunding campaign page.

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Physical fitness linked to lower cognitive impairment in dementia

Dr Eddy Davelaar from the Department of Psychological Sciences discusses the importance of physical fitness in offsetting cognitive impairment in adults with dementia.


Dementia and cognitive impairment cost the UK economy approximately £26 billion per year. The number of people with dementia in England and Wales has been projected to increase by 57% from 2016 to 2040, primarily because of extended life expectancy. Finding ways to slow its severity and progression could have life-changing effects for the 800,000 people estimated to be living with dementia in the UK.

With the increased incidence in dementia, people are interested to know whether it could be prevented through changes in their lifestyle, such as eating habits, exercise, and decreased environmental stress. Research does suggest that a healthy lifestyle lowers the risk of dementia. We were interested in physical fitness as one of the lifestyle factors. In our recent article published in Frontiers in Public Health, we asked the question of whether self-reported physical fitness is associated with cognitive, or thinking ability in people with dementia.

To assess this, we used a cross-sectional design with two groups. The first group was made up of 30 older individuals (aged 65+ years) with dementia, who were attending the Alzheimer’s café social events. Those people in the dementia group have lower cognitive performance than the 40 age-matched participants from our control group, who do not have dementia.

We tested everyone on a wide range of cognitive tests, such as verbal fluency, prospective memory, and clock drawing. We also administered a 15-item questionnaire on physical fitness, which asked about strength (eg. ability to lift things), balance, and aerobic conditioning (eg. taking a brisk walk or taking the stairs instead of lifts). Many studies have shown strong correlations between self-report and objective measures of physical fitness. In addition, this questionnaire is available to everyone for self-assessment.

Our findings showed that in the group of dementia patients, those with greater physical fitness also had a greater general cognitive ability. Even those patients with the best cognitive performance still performed worse than the healthy individuals, who did not show this link between physical and cognitive fitness. Thus, physical fitness seems to buffer dementia-related cognitive deterioration.

We ran a number of checks on the results and found that the association did not change when we controlled for the age of the participants, the number of years since dementia diagnosis, the type of dementia, or even whether the person used to be physically active when they were younger. The latter finding suggests that the current state of being physically fit and capable is key to observing this cognitive benefit.

There are at least two explanations for these findings. First, the cardiovascular hypothesis states that physical activity stimulates blood circulation in frontal-striatal circuits (neural pathways that connect frontal lobe regions with the basal ganglia that mediate motor, cognitive, and behavioural functions within the brain), that are critical in executive functioning, such as planning and reasoning.

A second hypothesis suggests that physical fitness measures, such as strength and balance, require efficient brain representations of motor plans. The processes by which these motor representations become more efficient also leads to enhanced cognitive representations. Both hypotheses underscore the expression, ‘what is good for the heart is good for the brain’.

We are currently in the process of addressing the question of whether physical fitness (using both self-report and objective measures) is associated with cognitive decline or cognitive impairment in the absence of dementia. This would assess whether greater physical fitness is associated with greater mental fitness in general, or with cognitive fitness specific in the context of dementia.

Future research could also extend this work using longitudinal study designs in order to address the question of whether a change in physical fitness is associated with a change in the risk of dementia, which has important implications for health policy and age-appropriate physical intervention programmes for both healthy individuals and dementia patients.

Read the original, peer-reviewed article: Increased Physical Fitness Is Associated with Higher Executive Functioning in People with Dementia (2017).

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Eating Disorders in Type 1 Diabetes

Jacqueline Allan, PhD candidate and Associate Lecturer in Psychology, at Birkbeck discusses the little known but extremely dangerous prevalence of eating disorders in Type 1 Diabetics, and her charity Diabetics with Eating Disorders.

In 2014 I was lucky enough to be granted a Bloomsbury scholarship to undertake a PhD focussing on Eating Disorders in Type 1 Diabetes, including one known as ‘Diabulimia’, at Birkbeck. I’ve worked in this area since 2009 when I founded the registered charity Diabetics with Eating Disorders.

First, let me explain what Type 1 Diabetes is.

Type 1 Diabetes is an autoimmune disorder where the insulin-producing beta cells of the pancreas are mistakenly destroyed, making sugar in the body impossible to process. Insulin is one of the most vital hormones in the body – it ferries energy we consume in the form of carbohydrates to our muscles, organs and brain, so it is essential for every bodily function. For this reason, those with Type 1 must check their blood sugar every few hours and administer synthetic insulin to keep themselves safe. There are two main ways for administering insulin – Multiple Daily Injections using both long acting and short acting insulin, or Subcutaneous Infusion using an insulin pump.

Most of us utilise a carbohydrate-counting approach, whereby we know how many insulin units we need for every 10 grams of carbohydrate consumed and what our general background levels should be. If it sounds like a simple equation, it’s not.  Everything affects blood sugar – not just the obvious stuff like sports, illness or alcohol but stress, the weather, sleep, menstruation – its educated guesswork.

When it goes wrong, we are in immediate danger of death. Too much insulin and we can’t think as there is not enough fuel in the cells of the body. We shake, seize, our bodies have a fight or flight reaction and if not treated with sugar in a timely manner we risk falling into a coma and/or dying. Too little insulin and the body has to find other ways to get rid of sugar and provide energy for itself; sugar escapes into the bloodstream and is excreted in the urine while the body starts burning fat and muscle for fuel. The calories consumed can’t be processed and are not utilised, so the body is forced to cannibalise itself for energy. This process is called Diabetic Ketoacidosis – it is a life-threatening condition and the main symptom is massive weight loss. In this sense, we are borne into a world where everything is about food, injections, the looming threat of complications, hospitals and numbers with the knowledge that ignoring it all results in a substantial reduction in body size.

For decades, research has shown that those with Type 1 Diabetes have higher levels of eating disorders that their non-Diabetic counterparts. Anorexia, Bulimia and eating disorders not otherwise specified (EDNOS) are twice as prevalent, and insulin omission is present in around 40% of female patients. The statistics for men are not as clear but levels have been rising steadily since the early 90s.

My research looks at risk factors for the development of Eating Disorders in Type 1 Diabetes. I started my PhD in 2014 and found that there is a psychological vulnerability which, when combined with Diabetes-specific distress predicts higher eating disorder symptomology and higher levels of blood sugar. Having modelled these risks, I developed a multidisciplinary intervention delivered online to address them. I am in the process of writing them up at the moment, but initial results are positive.

I am also looking at another important question – are we measuring the right thing? One common feature of standard eating disorder questionnaires is that they ask questions which could directly relate to diabetes regimen, rather than eating disorder symptomology – for example, questions like ‘do you avoid specific food groups?’ Many Type 1 Diabetics deliberately avoid carbohydrates in order to control blood sugar as a lifestyle choice rather than an eating disorder. Similarly, many people investigate this population by asking these standard questions that are fundamentally flawed, without acknowledging the issue that insulin omission leads to weight loss.

We have made substantial inroads into treating Eating Disorders in Type 1 Diabetes and it has been a privilege to be involved centrally with that research. The National Institute for Health and Care Excellence (NICE) guidelines published earlier this year marked a watershed in recognising the issue, as did the documentary and radio piece with the BBC. There are now two NHS Trust programmes that deal with diabulimia which is more than when I founded the charity in 2009. We still have a long way to go.

The next big hurdle is recognising that Eating Disorders in Type 1 Diabetes is fundamentally different due to the nature of the illness itself and that insulin omission and diabulimia are unique. Hopefully, my research will help with that.

Watch: Diabulimia: The World’s Most Dangerous Eating Disorder

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