Statistics for Biologists

Most of the biologists, ecologists and zoologists I know dread the moment they have to sit down with their data and start their statistical analysis.

Even those that understand the importance of statistics often don’t really know which test to perform or what the output actually means. And I have to admit, I’m one of them!

Or at least, I used to be. My understanding of statistics has got better in leaps and bounds since reading Professor Andy Field’s book. Discovering Statistics Using SPSS (Introducing Statistical Methods series).

I’ve pretty much read this book cover to cover and it’s great – I hugely recommend it.

For the first time I actually understand (within reason!) what test to use when, how to run it, what it means, how to interpret it and how to report it.

Prof Field really knows his stuff and, more importantly, can get it across in a way that actually makes sense.

Yes, he does go off on random tangents about his cats and his childhood, which I can see some readers would find annoying; but to be honest, I quite enjoyed it.

If I’m going to have to sit down and read a book on statistics I’d much rather there was a bit of humour in it rather than it being just a simple dry textbook.

That being said, if you want or need to use the book as a straight-forward, how-to set of instruction on using SPSS to run a statistical test, you can: the layout of the chapters and sections is very clear.

I especially liked the suggestions on how to actually report the results of each test, which some books tend to forget about.

I know some biology-type folk turn their nose up at SPSS, preferring mini-tab or R, but for everything I’ve needed to do so far SPSS has been great – and armed with Prof Field’s book I can usually get my analysis done (and crucially - understood) before they’ve even figured-out how to input their data.

So if you need to use SPSS buy the book from Amazon.

Should the UK be peat free?

The use of peat by the horticultural industry has long been a controversial issue in the UK, and now the argument is becoming more heated than a well-maintained compost heap.

The British Government have announced plans to ban peat from all amateur gardening products by 2020 and a similar phase out for the professional horticulture sector by 2030.

Recently the popular celebrity organic gardener Bob Flowerdew hit the headlines after saying he would continue to use peat, even if it meant buying it on the blackmarket.

I'm often asked my thoughts about going peat free and I have to confess I can see both sides of the argument - though I can only talk from my own experience with the horticultural industry and commercial peat producers.

When you're standing on a harvested peat field and all you can see are acres and acres of black, bare peat the knee-jerk reaction is to say such an activity is wrong and must be stopped.

Peat extraction in Canada. Photograph: Christian Dunn

However, as a pragmatic environmentalist you have to try and stand back and look at the whole picture.

Peat is a very important growing media, which for various biological, chemical, physical and economical factors is used extensively in all types of horticulture from the back yard gardener to huge industrial growing facilities.

In fact, most of the lettuce you eat in your sandwiches will have been grown in peat-based compost.

There are, of course, alternatives to peat and there is always research being done to improve these. But from what I've seen there still appears to be nothing out there to fully rival peat.

Some alternatives don't give good enough growing results while others are too expensive, either economically or in terms of the energy used and the carbon footprint created to manufacture them.

Now, perhaps these issues shouldn't be overly important to an amateur gardener, who should be prepared to pay more for his peat free compost and accept lower germination rates.

But for the growing industry in places like the Netherlands, trying to keep up with ever increasing food demands, it could be very harmful: closing down businesses leading to job losses and damaging fragile economies.

I don't think anyone can simply say all peat-based composts are a bad thing. Should alternatives be used wherever possible? Of course. Should amateur gardeners use peat-based composts? Probably not (I try not to!).

I do think we should definitely try to reduce our dependency on peat and any company wanting to extract peat, in whatever country, should have to come up with an in-depth peatland restoration programme and be held accountable to it.

Interestingly it is often the manufactures of peat composts that are investing the most in researching alternatives to peat and, the ones I have spoken to, take restoration and re-vegetation of their extracted fields very seriously.

If we were to stop all peat extraction, who would pay for this in the future as there are many historically extracted sites that still need direct management if they are to ever become peat-producing sites again?

So perhaps an outright ban of peat is not the best way to go - instead we need to balance our use of peat with the rate of extraction and restoration of harvested sites.


Here is the final report from Defra regarding the UK becoming peat free:
http://www.defra.gov.uk/peat-taskforce/files/SGMTF_Final-Report.pdf

The need to consider peatland-geoengineering

I recently wrote an article for Wetland Science and Practise, which is published by the Society of Wetland Scientists.

In it I argue for the need to consider peatland-geoengineering as way of cooling our climate.

This means looking at ways of harnessing the unique biogeochemistry of peatlands to capture and store more carbon – which is what my PhD is all about.

We believe this is not only possible but could be more cost-effective, efficient and safer than other proposed bio-geoengineering methods, such as aforestation.

Some members of the wetland scientific community are, for various and obvious reasons, reluctant to use our peatlands for such projects.

However, I end the article by posing a question:  “Should we leave our peatlands alone, while average global temperatures continue to rise, if they have the potential to significantly reduce greenhouse gas (GHG) levels?”

If you’d like to read my article please get in touch.

Seagrass stores more carbon than forests - but they still can't match peatlands

A study has shown seagrass beds can store twice as much carbon as forests but that's still only a fraction found in peatlands.

Researches say the soil underneath endangered seagrass meadows - which cover less than one percent of the world's seas - contain 10 percent of all the carbon buried annually in our oceans.

This equates to around twice the amount of carbon found in the soils of the world's temperate and tropical forests.

By conserving and restoring our seagrass beds it is hoped we can enhance these carbon stores - further reducing greenhouse gas (GHG) concentrations in the atmosphere.

This is a really interesting piece of research and could offer a viable bio-geoengineering technique, with the added benefits associated with safeguarding such a rare ecosystem.

However, this highlights once again just how important the northern hemisphere's peatlands are, with their stores of carbon dwarfing both seagrass beds and forests.

Seagrass beds, according to the report published in Nature Geoscience, contain up to 19.9 Pg of carbon (one petagram, Pg, is equal to one billion metric tons), peatlands total at 455 Pg though is more than 20 times that amount.

Indeed, peatlands are the world's most important long term depository of carbon and have a direct effect on GHG levels and our planet's climate.

Proper management of our peatlands is clearly essential if we wish to maintain this carbon stock, but so too is further research into possible peatland bio-geoengineering projects to increase carbon sequestration.


More information on: Seagrass beds can store twice as much carbon as forests

World Wetlands Day at Bangor University

Yesterday (February 2) was World Wetlands Day and I put together a piece about our research team's work for the Bangor University website.

World Wetlands Day marks the date of the adoption of the Convention on Wetlands on 2 February 1971, in the Iranian city of Ramsar - known as the Ramsar Convention.

The aim of of the event is to help raise public awareness about the importance and value of wetlands.

Follow the link to read what we get up to at the Wolfson Carbon Capture Laboratory.

Here's the description of my PhD research project:

"I’m looking at developing geoengineering techniques to increase the amount of carbon stored in the world’s peatlands. If we can come up with a safe, cost effective way of doing this it may be possible to absorb some of the excess carbon dioxide in the Earth’s atmosphere. It’s hoped this could start to reverse the effects of global warming; saving many species and eco-systems which are at risk of extinction, and even stop catastrophic shifts in our weather patterns and rises in sea levels. The work also has more immediate financial benefits, as any additional carbon stored by peatlands can be accounted for and sold on emerging carbon markets.
I get to look at all types of peatlands, from blanket bogs on our doorstep here in Snowdonia, to the mangroves in Florida and from Arctic permafrosts to tropical swamps."

Search a Twitter feed with Google

Here is a really simple way to search through someone's Twitter feed / stream with Google, to find a specific word or phrase.

To search a Twitter stream or feed simply type " site:twitter.com/USERNAME " into the normal Google search box - without the quotation marks and replacing 'username' with the Twitter address of the person or organisation your're interested in.

After this type the word or phrase you're searching for.

For example, to find what I have been saying about the climate on my Twitter account you'd type into a Google search: site:twitter.com/christiandunn climate

For most feeds Google seems to have around a two week delay in indexing tweets, but other than that it works pretty well.

Official hashtag for COP 17

The 17th Conference of the Parties (COP17) to the United Nations Framework Convention on Climate Change (UNFCCC) starts on 28 November, 2011, and takes place in Durban, South Africa.

There's already plenty of discussion about the meeting on Twitter and this is likely to increase a lot during the event itself.

To make the conference easier to follow on Twitter people will be using certain hashtags and it seems the 'official' hashtag will be #COP17.