Systematic Reviews

ploughed

Before I came to TCD, I spent my last six months at Lancaster University working with Dr Georgina Key on a systematic review of methods to make agricultural soils more resilient to threats like climate change, and erosion. What is a systematic review I hear you cry? Allow me to elaborate, and share some of our experiences from doing something slightly different.

A systematic review draws together and summarises the available scientific literature surrounding a particular topic or method. The Cochrane Collaboration, which produces systematic reviews in medicine and healthcare, defines such reviews as “a systematic, up-to-date summary of reliable evidence”. The aim of a systematic review is to provide the public, policy-makers and practitioners with a clear, unbiased picture of the latest, most reliable science on a certain practice, so that they can make informed decisions on how suitable that method is likely to be for them.

The goal of our systematic review was to produce a list of actions that could be used to improve the resilience of agricultural soils under pressure from a variety of threats. The first steps we took involved coming up with a list of key issues that would be important to manage agricultural soils in order to maintain sustainable food production in the future. We then took to the peer-reviewed literature, searching for experimentally tested solutions to the issues we’d identified, using a combination of journal trawls and keyword searches.

Journal trawls involved identifying relevant journals, like Soil Use and Management and Geoderma, then systematically searching all volumes of each journal for articles involving the issues we’d identified. Our keyword searches took a more targeted approach, using combinations of keywords to whittle down a selection of relevant articles. These approaches produced a large number of articles – far too many to summarise effectively in the time available – so we shortlisted them based on a number of criteria, foremost of which was ‘Has the action (e.g. non-inversion tillage) been tested using a robust, experimental design?’ We also filtered our keyword searches, carried out in ISI Web of Science, to the top 100 results, sorted by relevance.

Having eventually come up with a list of articles that tested the actions we’d identified, we set about summarising them. This was done according to a set template, using a specific style. This was initially restrictive, and difficult to adapt to – each article had to be summarised using specific vocabulary, within 200 words – but it ensured that the summaries would be understandable by people without a science background, and that the key message of the article wouldn’t be obscured by our own prejudices regarding the research.

Writing the summaries was the most time-consuming, but also one of the most rewarding, aspects of the project. By writing lots of summaries, we started to develop more of an understanding of how to write about science in a way that completely avoided jargon. This isn’t as easy as it sounds! But it is a vital skill for scientists to learn, in order to communicate their work to the public, and the people who will eventually turn it into policy. Having read lots of abstracts, those that stood out were the ones that communicated the message of the paper succinctly, in language that a non-expert could understand.

The article summaries and key messages from our short synopsis are now online– you can select an ‘action’, and read through the key messages, definitions, and all the evidence that we found and summarised for the use of that action, and its effects, in agriculture. I think there’s real value of having all this information collated together in one place, and communicated in an understandable way. Our soils synopsis is one of a number of synopses that you can browse through on the NERC Sustainable Food Knowledge Exchange Programme website.

Although it was only a short project, putting the synopsis together was a rewarding experience for both of us, particularly in terms of communication skills developed and networks joined. The synopsis that we produced is by no means the final product, and will need to be updated in the future to keep up with the amount of continual research in this area. The next step is to assess the synopsis, and its implicit recommendations, by asking experts and practitioners in the field how effective they think the research we covered would be, if it was implemented. This step should provide valuable feedback, helping to highlight any gaps in our synopsis, as well as improving future synopses.

Authors: Mike Whitfield and Georgina Key

About the authors

Mike Whitfield has a PhD in peatland carbon cycling from Lancaster University. Last year he helped to design and implement a long-term grassland biodiversity experiment in the Yorkshire Dales and worked with Georgina Key on the soil sustainability synopsis for six months, before moving to Dublin. Mike’s current postdoc at TCD focuses on modelling greenhouse gas emissions from agricultural land, with the aim of producing a map of estimated greenhouse gas emissions from soil for the whole of Ireland.

http://mikewhitfield.co.uk

Twitter: @mgwhitfield

Georgina Key has a PhD in ecosystem service provision, specifically conservation pest control. Having completed her first postdoc at Manchester reviewing literature on maintaining soil fertility, she is currently doing an assessment of the literature in collaboration with Cambridge University and Waitrose. In the future she hopes to work with tea and coffee companies, implementing sustainable growing practices and improving rural livelihoods.

Email:georginakey[at]outlook.com 

Twitter: @KeyGeorgina

 

Image credit: Treehouse1977 on Flickr


 

Earth day

children_holding_hands_around_the_world1

Monday 22nd April was Earth Day. In schools and offices all around the world people organised events to highlight the importance of the Earth and the harm that climate change, deforestation, and other human impacts are causing.

As an ecologist and someone who cares about conservation I should welcome Earth Day and its relative, Earth Hour, with open arms. Shouldn’t’ I? Maybe, but I really can’t. In fact, I find these sorts of events incredibly frustrating. Implicit within them is the idea that if we spend one day really caring then we can spend the other 364½ how we like.  I know that this is not the intention but I fear it is the reality.

Earth Day is popular with companies trying to improve their ‘green’ image, and it is here I have a big problem. I have no issue with companies trying to improve their green credentials, but improving their image and improving their credentials are not the same thing. How ‘green’ is a company who decides to spend Earth Day extoling the benefits of re-using cups at the coffee machine when the next day they send staff on a ‘training course’ that just happens to be in a hotel in Portugal? Who cares if you encourage everyone to print double-sided if you then require that 1,000-page file to be photocopied five times and then sent to offices all around the country (yes, I am drawing on past experience in these examples!).

I understand that Earth Day, and similar initiatives, try to encourage people to make small changes that are of little consequence in themselves but multiply over many people to make large differences. People are encouraged to turn off lights, the TV, their computer, and so on, when they’re not being used for long periods. The most commonly given reason for doing this is to ‘save you money’. After all, we live in a capitalistic society where money drives many of our decisions and if we can use money to drive lower energy consumption then everyone wins, surely?

Well, no. The problem comes from the rebound effect. If you save money on your heating bill most people don’t just say ‘yippee, I’ve saved money on my heating bill’, they say ‘yippee, I’ll put those savings into the holiday fund’ or similar. So the money saved on heating goes towards a flight to a tropical paradise where you stay in a five-star hotel for a week and lounge on the beach. This doesn’t exactly help the environment.

And this is where my biggest problem ultimately lies. No matter how hard we try to reduce our energy use, whether it’s through small behavioural changes or making things more energy efficient, the rebound effect will get us every time. I don’t know what the solution is but I think that this is something that really needs to be discussed publicly.

Sometimes the causes and effects of climate change can seem so overwhelming that people (myself included) want to give up, believing there’s nothing they can do. Unfortunately, there’s some truth in that. But one thing we can do is realise that it is overall effects that we need to consider, not individual ones. It’s not a very sexy message or one that is easy to sell, but unless it becomes the focus of the discussion then Earth Day is going to be nothing more than a wasted PR exercise. And that’s a real shame.

Author

Sarah Hearne: hearnes[at]tcd.ie

Photo credit

http://thinkloud65.files.wordpress.com/2011/01/children_holding_hands_around_the_world1.gif

Thunder lizards + methane = climate change

Mathematics is the language of science and when it comes to biology this is no exception. It’s only when you start researching for yourself that you realise how useful a skill it is. Consider, for example, the mathematical approach that Graeme Ruxton and collaborators bring to their research in ecology and evolution. Ruxton has addressed questions ranging from the foraging radius of vultures to a hypothesis proposing that sauropod dinosaurs produced enough methane, a la modern cows, to affect the climate of the time. The latter paper does seem to ask an intractable question on first inspection given that the animals have been extinct for at least 65 million years. So how do the authors even begin to tackle their question?

Mathematically of course. To begin, they estimate the population density of sauropods during the Jurassic Period from fossil data. Then they take a medium sized sauropod like Apatosaurus louise, which weighed around 20,000kg, as a representative animal. Finally they apply a relationship which gives an indication of methane production per animal, while being careful to note the relatively shorter Mesozoic day:

Methane (litres per day) = 0.18 (body mass in kg) 0.97

Multiplying it all out and the bottom line is that these beasts could put out 520 million tonnes of methane per year into the atmosphere. Incredibly, this is comparable to modern day emissions when the effects of this are apparent to all.The upshot the authors draw is that sauropods were drivers of climate change during the Mesozoic Era. There are some uncertainties in the paper to be sure. For one, the metabolism of dinosaurs is still an unknown and this has implications for their output. But the argument seems to be a sound one and this was all achieved with some fairly basic maths.

References

1. Ruxton, GD, Houston, DC (2002). Modelling the energy budget of a colonial bird of prey, the Ruppell’s griffon vulture, and consequences for its breeding ecology. African Journal of Ecology. 40 (3) p. 260–266.

2. Wilkinson DM, Nisbet EG, Ruxton GD (2012) Could methane produced by sauropod dinosaurs have helped drive Mesozoic climate warmth? Current Biology 22: R292-R293. DOI: http://www.cell.com/current-biology/retrieve/pii/S0960982212003296

Author

Adam Kane: kanead[at]tcd.ie

Photo credit

Todd Marshall