Codename COBRA: measuring and comparing diversity

One of the great discoveries of the last century was in the value of diversity, and biodiversity in particular. It is a lot easier to remove diversity than it is to maintain or improve it. Build a wall, chop down a forest patch, relax legislation and diversity will tend to decline. It takes effort to increase diversity so we should have a good reason for doing so.

Jagoba sampling spider diversity in alpine tussock grasslands. Image from Adrian Paterson.


We now know that diversity adds a great deal of resilience to a system, especially in times of crisis. An ecosystem with depleted species diversity can maintain itself for a long time but when that prolonged drought hits, a new generalist predator arrives, or manufactured chemicals enter the food chain, these communities are more at risk of extinction than those with higher diversity. Why this might be is still not completely understood but one element is that the higher the diversity the more likely that at least one species can deal with the crisis which may allow other species in the system to cope better.

Diversity is much on my mind at the moment as our Department of Ecology has had a major reduction in size. As part of a cost-saving measure we lost seven staff out of 19 (four academics, one technician and two senior tutors). All of the staff had been with us for over a decade and had contributed to a successful department. We had a stable ecosystem with reasonable diversity. The merits of why one department in our science faculty had to make all of the job losses is something to discuss another day. Suffice to say that in an agricultural-based university ‘ecology’ makes for an awkward bedfellow.

As a consequence we have been scrambling to figure out what we can and can’t teach/supervise/research. Where we had a nice spread of academics with a wide range of research interests there are now some gaps. Already we have had a couple of inquiries from potential postgraduate students who have interests that we no longer can cover confidently. The remaining staff have all had to start doing things that we are not as well adapted for compared to the staff who have left.

Pitfall in a paddock. Sampling diversity in an agricultural setting. Image from Adrian Paterson.

I guess we could argue that, in the meantime, diversity has helped ecology to survive at Lincoln. Three years ago we were a thriving department, a complex ecosystem. A crisis hit and which saw the removal of three academic staff. We carried on with a less diverse ecosystem but managed to cover the gaps. This next crisis have further depleted our diversity. One could argue that we have maintained the ecosystem through resilience but that we are now at the lower end of the diversity needed for this ecosystem to survive. Unless we regain some diversity we are unlikely to survive another crisis.


Empty offices. Image from Adrian Paterson.

Diversity is also on my mind as a former PhD student of mine, Jagoba Malumbres Olarte, has just published a paper from is post doc research on how to count diversity and sensibly be able to compare with other counts from different parts of the world or other types of ecosystems. Jagoba, based at the University of Copenhagen, looked at datasets of spider collections from areas in tropical forests in Guyana, Madagascar (two), and Tanzania. He and his colleagues were interested in whether you could develop a standardised collecting method which would allow for the collection of an accurate estimate of diversity AND be able to compare diversity between these regions.

To do this they developed the COBRA (Conservation Oriented Biodiversity Rapid Assessment) protocol. While this sounds like something that G.I. Joe or Jason Bourne might have to deal with on one of their missions, Jagoba show, in a paper in the journal Ecology and Evolution, that by using a bunch of different collecting methods and then optimising  them to maximize the diversity discovered while minimizing the sampling effort, that it is very possible to develop a protocol for your ecosystem. Measuring biodiversity like this will allow us to more easily estimate which ecosystems are likely to have issues with declining diversity. They found the best mix of methods to use to optimise sampling in tropical forests, maximizing the usefulness of the information while minimizing the costly fieldwork.

We are testing the COBRA approach ourselves. Masters student Kate Curtis is developing the protocols to test for diversity in agricultural environments. This will let us test whether diversity survives better in certain types of farming practices and comment about the resilience of such systems.

Sadly, however, I don’t need a fancy COBRA protocol to assess diversity in my department. I can simply count the number of empty offices.

One comment

  1. The drylands of the Mackenzie Basin have phenomenal diversity, and species rarity including within pastoral lands. Ecosystem connectivity is understood to be an essential for sustaining this biota. I was therefore surprised to see Lincoln Uni put out a proposal for a Mackenzie Country Drylands Park that appears to instead encourage fragmentation. It looks data deficient – perhaps the Ecology and Landscape Architecture departments do not collaborate.

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