Is integrity in species and subspecies important for captive populations?

An issue that has been on my mind for a good many years is whether integrity of species and subspecies is in any way important for maintaining captive populations. Is it a measure of their validity?
It would be worthwhile to explore the forumsters’ views on hybrids and crossbreeds in captive populations of endangered species. Is it detrimental to maintain the integrity of valid (sub-)species? Alternatively, do you feel there are cost / benefits involved in the practice? Is it acceptable, necessary, unavoidable et cetera et cetera.
Examples where this applies are sometimes entire captive populations or part of individuals comprising a captive stock maintained by some or quite of few zoos. Quite a number of megavertebrates come to mind like elephant, giraffe, a good number of the Carnivora (except perhaps the majority of tigers and leopards in established conservation breeding programmes), wisent/bison (it has been discussed elsewhere fleetingly). Not to name assorted bird, reptile, amphibian and other taxa / fyla.

Opinions most welcome!

 

Cross-breeding sub-species, difficult subject. I mean, subspecies are a man-created name for a surtain taxon. In my opinion such subspecies which have the possibility in the wild to meet eachother, because they live near each-other without a real natural barrier, cross-breeding can be made if there are to few animals for a healthy breeding-programm.
In subspecies which can´t mix together in the wild - for example bad swimming mammals on islands - the subspecies should be kept seperated as long as possible.
Further their are subspecies which are very different from each-other and these also should be kept seperated.
Others are more man-created sub-species - given a name because their fur is somewhat longer, the feathers are a little more red than that of another popuation or it has a small extra scale between the eyes - and in such cases maybe DNA-research can be done to show if they are different taxons of it they are the same subspecies.

 

DavidBrown will tell you that giraffe subspecies do not interbreed in the wild in areas where their territories overlap, yet they do in zoos. In my opinion, giraffes are a prime example of an animal that should not be interbred.

However, in the interest of conserving a critically endangered species then by all means interbreed them. After all, a moggy tall animal with spots is more of a giraffe than having none left at all.

 

Vogelcommando has hit the problem on the head. Subspecies (and even full species) are constantly in flux in regards to how we define them. Jaguars are a good example. At last count (or at least last I heard) they were considered one monotypic species with no subspecies. However another recent study suggested four subspecies (I think it was jaguars, but maybe it was pumas?).

Personally I think subspecies should be kept separate in captivity whenever it is feasible, and hybridized when it is not feasible. I believe in fact this is the current practice of the zoo industry. The primary rationale for keeping them separate is of course for future reintroductions. The problem with subspecific programs is that there is often only room for one subspecies, forcing zoos to display out of character animals. The amur leopard is a good example. AZA zoos with leopard exhibits in their Africa section (think The Living Desert) have to display amur leopards and pretend they are african leopards.

 

I agree with what has already been said - subspecies should be preserved if its feasiable and possible; I'd rather two species were saved and preserved than losing one, but maintaining two sub-species of the other. If a species is generally highly endangered or a particular subspecies is facing extinction, I think it is justified to hybridise them to attempt to increase save some of the unique genes from that population. Potentially these hybrid aniamls would possess the correct genetic material to be able to adapt to their habitat if future reintroduction were to occur.

Also I think difficulties arsie when trying to decide what a sub-species is. For example in tigers there is a clear distinction between the Sumartran and Amur, but if you look at Panthers, are the subspecies "man-made" due to human habitation and persecution creating unique pockets. (Im thinking about the Florida panther and if it use to be just part of a Texas/Southern strain)

 

yes when the species itself is at "Critical levels" then yes we shouldn't be worrying about subspecies especially since like people said the concept of the subspecies is constantly in flux.

 

In the wild wouldn't the natural evolution of species involve the in breeding of sub species?

My point being that it we are actually restricting natural evolution by not allowing sub species to breed together. I do acknowledge that this process would be over a extended period of time, however there would definitely be a time for them to reproduce.

 

In the case of mega-fauna I cannot help but feel inter-breeding recognized sub species is imperative to long term genetic diversity in the captive population. And as a safety net population the genetic prosperity of the produced animals should be of the utmost importance (at this point I'm discussing Asian elephants, but the same applies to Sumatran rhinoceros, and others).

 

I think that subspecies concepts remain valid and that the defining character may be population numbers and longterm outlook. Species and subspecies have evolved due in no small part to various environmental, climatological and geographical determining factors. Physical barriers between species (chimpanzee vs bonobo) or subspecies (Southern African sable vs Angolan giant sable) remain important determinants for evolutionary speciation.

In this respect the concept of single conservation units very much appeals to me. For example, it has been proposed that genetically ... (but is this due to the small set of genes investigated for mtDNA?) wild ass subspecies like kulan and onager are identical, yet the scaling by either of the Alborz/Elbrus Mountains is in complete impossibility. Similarly, the recent genetic studies on giraffe evolution and speciation have shown that hybridization more or less does not occur in the wild and that East Africa / Kenya-Ethiopia is the birthplace of all modern giraffe. I do feel that we cannot take this too lightly (and this is yet but a far cry from the 18th century concepts postulated over human evolution and later used for less savoury political ends).

 

Outbreeding depression can potentially occur between subspecies, so it must be taken on a case-by-base basis.

 

With all the taxonomic shuffling of mammals that is going on, I feel it would be best to keep purported subspecies pure until we are as close to absolutely sure of their taxonomy. That said, this is a pie-in-the-sky scenario.

 

Wolves are an animal that comes to mind in this sort of discussion. It seems that there is so much debate, with such a wide-ranging animal about how many subspecies there are and even if some should be classified as separate species. Looking at the AZA Tag it looks like only Mexican wolves are being maintained in the US and while that is a rare subspecies, there are plenty of others like Arabian and Indian wolves that are not maintained in captivity. Since these are both very rare subspecies it seems it would be a tragedy if they were to die out with no animals in captivity. The Javan tiger also reminds me of this scenario.

I apologize if I'm derailing the thread.

 

Elefante, no you are not derailing the thread ... it is intended in the widest possible sense to discuss the issue and examples from the wild are very much relevant to the discussion here.

Everyone feel free to comment further!

 

At the risk of further derailing the thread, there are Indian Wolves at Singapore's Night Safari. http://www.zoochat.com/243/singapore-night-safari-2008-indian-wolf-131211/

 

I agree with CambsVet. If it's feasible to keep subspecies and these can be maintained in enough numbers to maintain their genetic diversity, so be it. But I would still prefer zoos to conserve as many species as possible, rather than having hundreds of individuals of the same subspecies, with no possibility or desire to return any of these to the wild.

In 2011, I did a list of cats kept in captivity. Isis stated that there were at least 1663 tigers, including 463 Amur tigers, 376 Bengal tigers, 240 Sumatran tigers, 62 Malayan tigers and 61 North Indochinese tigers.
Only 4 species of cats had higher captive populations than the population for the Amur tiger: Cheetah: 2016; Lion: 1880; Tiger: 1663 and Leopard: 873
An additional four species had higher captive populations than the population for the Bengal tiger: Wild and domestic cat 440; Serval: 432; Puma: 407 and Snow leopard and Northern lynx: 398
An additional four species had higher captive populations than the population for the Sumatran tiger: Jaguar: 371; Ocelot: 267; Bobcat: 243 and Leopard cat: 241
An additional 10 species have higher captive populations than the Malayan tiger: Clouded leopard: 220; Fishing cat: 194; Caracal: 169; Sand cat: 157; Pallas's cat: 151; Jungle cat: 95; Jaguarundi and margay: 85; Geoffroy's cat: 82 and Canadian lynx: 63
The following species have lower captive populations than the North Indochinese tiger: Oncilla: 56; Black-footed cat: 55; Rusty-spotted cat: 47; Asian golden cat: 45; Colocolo: 10; Flat-headed cat: 8; Marbled cat: 4 and Iberian lynx: 3
The Chinese mountain cat, Iriomote cat, pantanal cat, kodkod, Andean mountain cat, pampas cat, African golden cat, bay cat, Bornean clouded leopard were all listed as having no captive individuals, according to ISIS.

I know this is a lot of figures, but it indicates how much more priority zoos give to a few subspecies of tiger rather than most species of smaller cats. If species lack captive populations and become extinct in the wild, they are extinct. Last year, I had a phone call from a WWF representative about the tiger becoming extinct. Due to the high captive population, I think there is very little chance of this, but I can see many smaller species becoming extinct and I would like zoos to do more to build up captive populations, with progeny being used to build up wild populations. A few weeks ago, I went to an EDGE presentation and heard about the work being done to save species in the wild. It's just a shame that so many EDGE species lack captive populations.

 

I agree completly with you, Dassie Rat. And if we think about the fact that ISIS only covers a small part of the captive populations, many more tigers, lions and so on are kept.
If a large part of the hybrid-tigers and other mixes-up cats ( lions, leopards and so on ) can be phased-out, lots of room can become avaible for pure tiger-subspecies, pure lions, leopards and small cats now under-represented or none-extant in captivity.

 

Thanks Vogelcommando. I agree with you about phasing out hybrids, especially when these take up a lot of space that could be used to save pure species.

 

In my own opinion, as some users have already stated, I would try to keep the 'bloodline' as pure as possible to preserve the subspecies. It would be nice to have a zoo or wildlife park someday have multiple subspecies of a species side by side in separate enclosures to show the differences to guests. But, as nanoboy had said, 'a moggy tall animal with spots is more of a giraffe than having none left at all'.

 

The travesty in that is it is not at all necessary. There are sufficient numbers of pure-bred giraffe around. Yet, quite a few zoos remain contend to breed hybrid / crossbreeds that do not exist in their natural habitat.

Same with the issues raised on generic carnivores. They occupy desperately needed captive space for endangered taxa. Of which once more there are sufficient founders to start up a conservation breeding program.