Sub-species to split species ?

[THWorthy]

Hi all, an interesting discussion.
Taxonomy is a separate thing from any checklist. A Species (or subspecies) status is created by taxonomic publications wherein a statement is made, and takes effect from the DAY of publication on paper. It is a totally valid thing to say I accept NI and SI kokao as distinct species and cite the original species authors or perhaps Holdaway et al 2001, contra the 1990 Checklist. Checklists, as will be the current one due for release shortly, are always conservative and tend to follow a majority of scientific opinion. In areas with few people (eg NZ) or on topics where few work or can see, eg NZ kiwis, there may be few papers and so for example most World Checklists have not caught up with the abundant data supporting 5 species.

The current in press checklist is a synthesis of a really huge amount of work that has been published and results in many changes from the 1990 Checklist. But for most of us the names used have been in use for the last decade by taxonomists. There are a few new species created since the 1990 Checklist, but most changes relate to raising taxa back to the species status that they were originally, and we now know correctly, were given. Some like the snipe are ongoing projects, with the recent paper by Colin Miskelly et al in Notornis already dating the unpublished Checklist. This is to be expected.

But It is my belief that the new Checklist will provide a very stable platform for new Zealand birders to work from into the next decade.

[Bruce McKinlay]

Hi,
Just to confirm Jan's post.
The 4th edition of the NZ etc. checklist will be launched at the OSNZ AGM.
There is a prepublication offer in the latest Southern Bird.

Looking forward to seeing you all at Nelson for further discussion.

Bruce

[Graham Saunders]

Does anyone have currently accepted definitions of 'species' and 'sub-species'? If so please would they share them with us. It would be good to know which criteria are being applied, or ignored.

[Ian Southey]

Graham

You are difficult and don't get an answer, only a lecture. Read or not as you please.

Regarding definitions of species there are "criteria" that tell you how to discover and recognise them. The kinds of things you will see written and drawn in field guides, keys etc. Then there are concepts that deal with the underlying processes that generate and maintain species. These concepts are largely theoretical although aspects of them do get tested in the lab and field and they are of great practical use when the accepted criteria start to become difficult to apply.

It is probably fair to say that there is no accepted species concept right now but dozens and dozens of contenders. The "Species Problem" reminds me a lot of the parable of the blind men and the elephant. All of them are dealing with essentially the same material but differing in what is thought to be important or not so that the products come out very differently. Basically there are two families of species concepts that reflect two kinds of hierarchical organisation in biology.

The older is the Biological Species Concept that reflects real time organisation into a functioning hierarchy, by which I mean levels like cells, organs, individuals, populations, ecological communities that work as wholes in some way. Here, in the broadest sense, a species is a interacting population that is largely discrete and seperate from other such populations. If you add in a little space and time you can imagine changes that might periodically link and isolate parts of such populations.

More recent is the Phylogenetic Species Concept which deals with an historic hierarchy which looks at trees of descent. You can easily see birds breaking into smaller groups included within larger groups, orders, families, genera etc like a family tree reflecting pattern of evolution over time. The key concept here is very simple, with older taxononmic levels, up to species, differences the branches of the family tree divide but at lesser levels they start to rejoin into a network as the individuals in the groups they repesent become able to interbreed.

Both of these are good ideas and the Phylogenetic Species Concept is particularly amenable to computer analysis while getting to the crux of Biological Species Problem can require you to actually become familiar with how the difficult animals are behaving out in the real world. To deal with the Phylogenetic Species Concept first (because I don't favour it) you need to know that the phylogentic method doesn't actually make trees of real ancestry and descent, but uses particular ways of measuring similarity and difference to divide groups. When you get to species level and below it keeps trying to divide and you are going to get out groups like blue eyed blondes rather Smiths or Joneses. There are two ways to know when to stop dividing, one is arbitrary and commonly used because it is practical and convention says that any group found to share at least one distinctive feature that is exclusive to it can defined as a species. The other way is to revert to what are essentially Biological Species Criteria that infer interbreeding relationships. What this means is that phylogenetic methods are very good ways to discover species but have a weak conceptual basis and may not be particularly useful to solve difficult problems. Also when you get species of hybrid origin such as those Whip-tailed Lizards or many plants the conceptual distinction between dividing parts of a phylogenetic tree up to species level and the network of banches within species becomes blurred.

Biological Species are populations in nature with stronger interactions (almost always read this as interbreeding relationships) within a species than between them. It has a good history as it allowed resolution of old problems like polymorphic species (eg Pied and Black Fantails) and cryptic species that are so similar to look at that you can't be sure they are different (can't think of a good local example).

It's recent past has been checquered by heavy use of genetic concepts that have been superceded or found to be just one of many alternatives. The most important of these may be that natural selection is now known to be often potent enough to combat gene flow so that a degree of interbreeding is not generally going to compromise the seperate nature of the populations involved. It is having a recent resurgence under the guise of "Ecological Speciation" which stresses adaptations to the particular circumstances in which each species is living. This includes obvious things like specialised feeding structures but many aspects of mating that were regarded as isolating mechanisms that had evolved to keep species apart may be better regarded as mechanisms that have evolved for more efficient communication. A split hair, perhaps, but an important one the less.

A new formalised species concept in line with this Ecological Species research program is much needed and could be promising as the kind of definition might consider traditional diagnostic characters as key evolutionary innovations or at least genetically linked to such things rather than as outcomes of interbreeding relationships.

Sorry, In spite of skipping lots I'm running out of steam and focus. Note this a personal and probably biased response and other people will have different views. I'll guarantee the authors of the checklist will have a different and more conventional angle. It goes with the job. If requested clarifiction may come later.

Ian

ps Subspecies is just as bad but I've no time for them, I use them only for a quiet life.

[Graham Saunders]

Thanks Ian, that's great. I think a lot of folks use these terms without really thinking about them, or knowing exactly what they are. Do you know which criterion is used for the NZ list? It appears to me that a lot of us lay taxonomists pick and mix the criteria applied, to get species in line with our ego-centric and prejudiced views. It is also not unknown for unscrupulous bird tour operators to unilaterally split species in what appears to be an attempt to drum up business for visiting a certain location. One character in the UK has split quite a few birds that occur in the British Isles into British and Irish species, and runs tours to Ireland to see the latter; somewhat unethical?

It's also interesting to note terms such as 'microspecies' and 'semispecies'. Man's desire, and failling attempts, to categorize everything is a fascinating subject.

[Suzi]

Excellent summary by Ian !

Also Graham, a few references relating to species concepts cribbed from my booklet of readings for CSU BIO431 Avian Systematics and Biogeography (2008), that you may find useful include;

Haffer J, 1997, Species concepts and species limits in ornithology, in Handbook of the Birds of the World, Vol4; Sandgrouse to Cuckoos, eds J Del Hoyo, A Elliott and J Saragaratal, Lynx Edicions, pp 11-24.
(Contains an excellent review of the species concepts).

Cracraft J, 1997, Species concepts in systematics and conservation biology - an ornithological viewpoint. In Species: the units of biodiversity, eds MF Claridge, HA Dawah and MR WIlson Chapman and Hall, London pp 325-340.

Newton, Ian 2003, Species formation; the speciation and biogeography of birds, Academic Press, London pp 75-79 and 84-91.

O'Hara, R 1991, Essay review of Phylogeny and classification of birds: a study in molecular evolution, by CG SIbley and JE Ahlquist, Auk 108, pp 990-994.

And of course an old favourite on this subject is Peter Grant's, Ecology and Evolution of Darwin's Finches, 1986, Princeton University Press with especially his chapter 10 on Evolution and Speciation p253+.

Suzi

[Ian Southey]

Graham

I expect that the New Zealand checklist will be drawn up from a Phylogenetic Species Concept as I think that is what, if anything, the members of the committee have used. It is also in common use around the world by practising taxonomists. In most cases it should work as well as any other.

Regarding taxonomic ranks below species, I'd say that anything worth formally recognising is best regarded as a species because I see them as being the cutting edge of evoluton as near as we can discern it. These other terms are meant to convey various meanings and are not necessarily intened to indicate lesser value although they may be regarded that way. Your character in the UK might actually be doing a reasonable thing regardless of whether or not his heart is pure.

I don't have much patience for those whose use for systematics and taxonomy is about whether they can tick a bird or not. The wealth of nature is just there to be appreciated and trying to see how a South Island Fantail differs from a North Island Fantail is the same test of ability and perception regardless of how you choose to label them. And if you are looking at this level you will start to see that there is more variety out there than is shown in the books and then it starts to get really interesting.

Ian

[Graham Saunders]

Ian, according to Wikipedia subspecies are not recognized in the phylogenetic system anyway.

It's interesting to see Darwin wrote this in On the Origin of the Species:
No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species.

... Things haven't really moved on that much, have they? Just lots of different types of species.

[THWorthy]

All answers to these issues should be now answered by perusal of all by their new Checklists. I hope you have now annotated your lists to reflect the many changes that have occurred in the 20 years since the last Checklist but if there are any queries I am willing to try and explain the individually

cheers Trevor