Does conservation biology need DNA barcoding?

5 01 2012

In November last year I was invited to participate in a panel discussion onthe role of DNA barcoding in conservation science. The discussion took place during the 4th International Barcode of Life Conference (which I didn’t actually attend) in Adelaide, and was hosted by that media-tart-and-now-director-of-the-Royal-Institution, Dr. Paul Willis.

Paul has recently blogged about the ‘species’ concept as it relates to DNA barcoding, which I highly recommend. It also prompted me to write this post because now the video of the discussion is available online (see below).

Now, the panel was a bit of a funny set-up in a way – I was really one of the only ‘conservation biologists’ represented (Patrick O’Connor and Andy Lowe perhaps excepted), with the rest mainly made up of molecular people (Pete Hollingsworth, Bob Hanner, Karen James) – and I was told prior to the ‘debate’ that I was meant to be the contrarian (i.e., that there is no role for DNA barcoding in conservation).

Fundamentally, I don’t actually embrace the contrarian view on this one given that I see no reason why DNA barcoding can’t enhance or refine our conservation knowledge and skills. But the ‘debate’ did raise some important issues about technological advancements in the application of conservation science to real conservation.

I suppose that prior to getting stuck into the polemic I should define DNA barcoding for the uninitiated; it’s a basic technique that analyses short sequences of DNA with the sole purposes of identifying from which species they come. Imagine walking through the bush with a barcode scanner and pointing at random species you see and getting an instant identification read-out without actually knowing the species beforehand. You can see why it’s called ‘barcoding’ because it is like running products through the check-out to get instant price details.

Some of the advantages for conservation should be immediately obvious – ‘forensics’ of the wildlife or illegal timber trade can be enhanced by letting authorities know the origin and pathway of illegally imported or marketed animal or plant products. This can give bodies like customs and quarantine departments a big legal stick to smash poaching rings, et cetera. Another is determining the presence of a rare species that is difficult or impossible to survey – for example, identifying DNA fragments of rare fish in samples of river water. Once identified using DNA barcoding, a legal argument to preserve that habitat on the basis of threatened wildlife legislation can be made without the expense and uncertainty of traditional wildlife surveys.

I suppose the main point of contention about DNA barcoding is that it merely refines our capacity to survey species we probably already know are in trouble. I submitted during the discussion that we could probably kill every single conservation biologist in the world and not really handicap ‘conservation implementation’ in any major way because we have the main aspects of the science sorted (fragmentation is bad; more habitat area = more species; climate change is bad; invasive species are bad; too few individuals is bad; small populations tend to go extinct; drivers of extinction synergise to make things worse – see full list on Conservation Classics). The principal conservation science discoveries have been made; now we need to manage the resource consumption of 7 billion humans more than anything else. You can also read more about conservation science ‘mucking around the edges‘ in a previous post here on CB.

Another potentially questionable application of barcoding to conservation is that it merely tells us if something is there, not how many or in what state. With a simple binary output, we lack some essential information regarding the value of an area based on mere presence/absence. Certainly we do now do area prioritisation based largely on presence/absence data, but how many more cryptic species identifications do we need to prioritise habitats for preservation?

Those somewhat philosophical beefs aside, I’m still very much in support of the concept of quantifying species better than the somewhat subjective and categorical binomial genus-species system we currently use. I’m also excited by the prospect of using DNA barcoding to quantify ecosystem health better by measuring soil and water microbia composition, and perhaps even starting to get a handle on soil fungus diversity. If we can even improve DNA barcoding to become ‘q-barcoding’ that quantifies relative abundance in addition to identification, we’ll really have a massively important tool for measuring ecosystem and species health.

I’ll be interested in CB readers’ opinions on the subject.

CJA Bradshaw



2 responses

28 08 2013
DNA barcoding plants with citizen science |

[…] they find in the Alaskan wild using only a tiny fragment of specimen for a relatively low cost. DNA Barcoding is a method of taxonomic identification that relies on obtaining DNA sequence from specific sites […]

11 01 2012

As a conservation program manager, I can see several useful applications of this kind of technology, especially if advanced to the stage where it can quantify. Firstly, along the lines of getting the best ‘bang for our conservation buck’ (a notion that I despise but is nonetheless popular in these times of market-based instruments), using a DNA barcoding ‘sweep’ of an ecosystem would be an ideal first step in the decision-making process about what further actions to take in an ecosystem or location. Are there threatened species present? If so, how many (species, not individuals) and can we use that as an argument for protection of the entire ecosystem or area? The kind of species present (threatened or not) may also lead into decision-making about further surveys – do we spend more money to carry out more detailed field surveys to estimate numbers of individuals? This may be important if species are suspected to be ‘threatened’ but are not yet listed and do not have enough population data to support a nomination to the EPBC Act, for example. So, using the technology to find species in the first place is critical.

Identifying these species where development applications are proposed would be another useful application of the technology.

For our program, we work both with an individual threatened species and a threatened ecosystem, so for us, being able to identify that this particular species is present or absent at specific sites is particularly important. At the moment this is done with expensive people power undertaking surveys. Using this technology could potentially reduce the time required and may possibly be more accurate – could it detect the presence of a species without actually having to see it? If so, this is a significant advantage over the use of people (although in our particular case we can sometimes hear our species even if we don’t see it).

I also see other applications along the lines you mentioned re quarantine and wildlife trafficking, with regard to fish fillet identification. At the moment commercial fish fillets are poorly labelled and very hard to identify without the rest of the body. For example, most tuna fillets are sold just as ‘tuna’ in most Australian supermarkets and the staff haven’t got a clue which tuna or where it came from. For much more effective labelling and chain of custody seafood monitoring, this technology could be very useful!

I look forward to the rapid development of this technology.

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