Tag Archives: food webs

On Alpha-Ecology

All science advances on the back of previous scientists. No advances can be made without recognizing problems, and problems cannot bet recognized without having completed a great deal of descriptive natural history. Natural history has been described by some physicists as ‘stamp-collecting’ and so has been condemned forever in the totem pole of science as the worst thing you could possibly do. Perhaps we would improve our image if we called natural history alpha-ecology.

Let us start with the biggest problem in biology, the fact that we do not know how many species inhabit the earth (Mora et al. 2011). A minor problem most people seem to think and little effort has gone into encouraging students to make a career of traditional taxonomy. Instead we can sequence the genome of any organism without even being able to put a Latin name on it. Something is rather backwards here, and a great deal of alpha-biology is waiting to be done on this inventory problem. Much of taxonomic description considers low-level hypotheses about evolutionary relationships and these are important to document as a part of understanding the Earth’s biodiversity.

In ecology we have an equivalent problem of describing the species that live in a community or ecosystem, and then constructing the food webs of the community. This is a daunting task and if you wish to understand community dynamics you will have to do a lot of descriptive work, alpha ecology, before you can get to the point of testing hypotheses about community dynamics (Thompson et al. 2012). Again it is largely a bit of detective work to see who eats whom in a food web, but without all this work we cannot progress. The second part of community dynamics is being able to estimate accurately the numbers of organisms in the different species groups. Once you dig into existing food web data, you begin to realize that much of what we think is a good estimate of abundance is in fact a weak estimate of unknown accuracy. We have to be careful in analysing community dynamics to avoid estimations based more on random numbers than on biological reality.

The problem came home to me in a revealing exchange in Nature about whether the existing fisheries data for the world’s oceans is reliable or not (Pauly, Hilborn, and Branch 2013). For years we have been managing the oceanic fisheries of the world on the basis of fishing catch data of the sort reported to FAO, and yet there is considerable disagreement about the reliability of these numbers. We must continue to use them as we have no other source of information for most oceanic fisheries, but there must be some doubt that we are relying too much on unreliable data. On the one hand, some fishery scientists argue with these data that we are overexploiting the ocean fisheries, but other fishery scientists argue that the oceanic fisheries are by and large in good shape. Controversies like this confuse the public and the policy makers and tell us we have a long way to go to improve our alpha-ecology.

I think the bottom line is that if you wish to test any ecological hypothesis you need to have reliable data, and this means a great deal of alpha-ecology is needed, research that will not get you a Nobel Prize but will help us understand how the Earth’s ecosystem operates.

Mora, C., et al. 2013. How Many Species Are There on Earth and in the Ocean? PLoS Biology 9:e1001127.

Pauly, D., R. Hilborn, and T. A. Branch. 2013. Fisheries: Does catch reflect abundance? Nature 494:303-306.

Thompson, R. M., et al. 2012. Food webs: reconciling the structure and function of biodiversity. Trends in Ecology & Evolution 27:689-697.