The giraffe (Giraffa reticulata X camelopardalis rothschildi) of the Laikipia region of Kenya is a hybrid, and no substitute for the real reticulated giraffe
@michalsloviak @chewitt1 @johnnybirder @jakob @jwidness @bobby23 @dejong @maxallen @mikeloomis @kokhuitan @calebcam @variani18
The typical appearance of Giraffa reticulata can be seen in and near Samburu National Reserve (https://en.wikipedia.org/wiki/Samburu_National_Reserve) in Kenya.
To the west of this, on a plateau just northwest of Mount Kenya, lies the Laikipia region. Laikipia county (https://en.wikipedia.org/wiki/Laikipia_County) is only part of the Laikipia region (https://wildlifedirect.org/wp-content/uploads/2018/06/CS-report-GGR-2018v-4.pdf and https://en.wikipedia.org/wiki/Laikipia_County).
The protection of a form of Giraffa on privately-owned lands in the Laikipia region has seemingly brought a success in conservation.
However, re-examination of the identity of this form may be sobering.
The following map of the Laikipia region shows the complex patchwork of properties which are being managed partly for the conservation of wildlife: https://kwcakenya.com/regional-associations/laikipia-conservancies-association/.
In iNaturalist there are currently nearly 130 observations of Giraffa in the Laikipia region, most of which have been identified as Giraffa camelopardalis reticulata.
The following, just beyond the Laikipia region to its northwest, has yet to be identified. However, it looks like Giraffa camelopardalis rothschildi:
https://www.inaturalist.org/observations/115397.
The following, from the western edge of the Laikipia region, has been identified as Giraffa camelopardalis rothschildi: https://www.inaturalist.org/observations/19525098.
The following, from the central parts of the Laikipia region, have ambivalent identifications:
https://www.inaturalist.org/observations/14224598
https://www.inaturalist.org/observations/46599973.
The following has been identified as reticulata. However, it fails to conform to that taxon:
https://www.inaturalist.org/observations/30528961.
Several other observations from the Laikipia region also fail to conform to reticulata with respect to at least two features, viz.
- the whitish 'matrix' is too broad on the distal part of the neck to fit reticulata, and
- the lower legs are whitish, resembling rothschildi rather than reticulata.
What the above suggests is that the whole population of Giraffa in the Laikipia region may be subject to hybridisation between reticulata and rothschildi.
Many individuals resemble reticulata closely enough to be identified as such by experienced iNaturalists. However, on closer examination even these may possibly reveal signs of hybridisation (see https://www.inaturalist.org/journal/milewski/59852-reframing-the-reticulated-giraffe#).
An intermediate status makes sense given that the Laikipia region is located between the original ranges of reticulata and rothschildi. But which form inhabited the plateau at the time of European arrival?
I suspect that
- Giraffa was largely exterminated from the Laikipia region during the initial period of farming by European settlers, the surviving individuals being hybrids for reasons that remain to be established, and
- with more recent conservation, the hybrid population may have spread, with the encouragement of landowners, to occupy most of the region.
What makes this ostensibly hybrid status all the more important is the growing realisation that reticulata and rothschildi belong to different species, not merely subspecies. If the population in the Laikipia region is an interspecific hybrid, its value for conservation is questionable.
We need to search the literature to establish which form was originally indigenous to the Laikipia region; was this a zone of natural hybridisation in the first place? It would also be helpful to document the degree to which the original population was depleted during the period when management was inimical to Giraffa.
We need to decide whether reticulata and camelopardalis are different species. In my view, one of the few reasons to doubt such taxonomic separation is the apparent fertility of the hybrids.
A questionnaire survey among landowners would be helpful, re the historical status of Giraffa on the various properties in the Laikipia region.
For now, I recommend that all current identifications of reticulata in this region be changed to reticulata X rothschildi. If the species-distinction is accepted, the change would be to Giraffa reticulata X Giraffa camelopardalis rothschildi.
The current assumptions give a misleadingly encouraging impression of the overall status of reticulata (see https://www.researchgate.net/figure/The-distribution-of-giraffes-in-Laikipia-Samburu-MarsabitMeru-Ecosystems-2017_fig7_325145734). Some 60% of what have been counted as reticulata Kenya-wide occur in Laikipia county.
This means that the remaining population of true reticulata, i.e. free of hybridisation, in Kenya is possibly only a third of what has been published recently.
There is no cause for complacency in the conservation of reticulata. This is because
- it may now be as rare (in true form) as the West African Giraffa camelopardalis peralta, and
- it may deserve the attention of a full species.
Comentarios
No matter what taxonomic division we prefer (whether reticulata and rothschildi are separate species or just subspecies), it is no good to recommended that we refer to Laikipia giraffes as hybrids. I think that is quite premature, not based on proper research. It is also very important that research is carried out on this particular issue. Just because referring to individual coloring according to individual observations does not mean that the whole area is necessarily affected by the hybrid population. According to my previous information, natural hybridization was known only from the northern parts of Tsavo East, in the area of the Galana River, where the G.c.reticulata and G.c.tippelskirchi populations met for centuries during the extreme drought. The Laikipia area, by being a place with a relatively large number of private ranches and reservations, of course gives room for hybrids as a result of human ill-considered translocations, but it is very unlikely that this could be done directly (maybe in the distant past, certainly not today). The distribution and current populations of giraffes in Kenya are namely being closely monitored. But also It is generally believed that the only net population of G.c.rothschildi in Kenya today occurs exclusively in the Lake Nakuru National Park. In the case of Laikipia, mainly for Ol Pejeta and Lewa private reserves (they are perfectly fenced and secured), I suspect that the atypical coloration of reticulated giraffes could have resulted from long-term isolation and thus weakening the genetic makeup of those populations, which may or may not directly lead to certain color changes or discoloration. Their populations since their establishment decades ago have not been replenished, and it is possible that they come from a relatively small number of founding animals. We also know this from the breeding environment in zoos, where after decades, changes in color develop in relatively clean and well-kept populations. And apart, of course, from private reservations, those giraffes have practically not existed there for decades. Therefore, it will be extraordinarily detective to accurately determine the extent of the original distributions of individual populations (today, a huge part of Laikipia is farmed, the animals here are extinct). But, the Meru area is questionable, and indeed it could lead to human-caused hybridism (not only giraffes, but maybe e.g. also Grant's Gazelle - N.g.nota x N.g.granti). In the past, I have pointed out a similar problem with hartebeest, where, unlike giraffes, it is already demonstrable that the population in Ol Pejeta is a hybrid of A.b.cokii x A.b.lelwel, although not everyone agrees
@michalsloviak If I understand your assessment correctly, what is needed is a proper study (i.e. an authoritative scientific reference) that has found that a) Giraffa reticulata is a species distinct from Giraffa camelopardalis, b) interspecific hybridisation occurs between these two species, and c) such hybridisation has been recorded in the Laikipia region.
All three of these requirements are unambiguously met by the following study: https://zmmu.msu.ru/files/%D0%91%D0%B8%D0%B1%D0%BB%D0%B8%D0%BE%D1%82%D0%B5%D0%BA%D0%B0%20%D0%9F%D0%B0%D0%B2%D0%BB%D0%B8%D0%BD%D0%BE%D0%B2%D0%B0/grubb-groves-2011_taxonomy_ungulates.pdf.
This latest formal revision of Giraffa has found the following (all on page 80). The authors:
a) confirm that G. reticulata is indeed a different species from G. camelopardalis (a species which is indeed confirmed to include Rothschild's giraffe).
b) cite Stott (1959) and Stott and Selsor (1981), who published properly in the Journal of Mammalogy and Mammalia respectively, and did indeed find hybrids between G. reticulata and Rothschild's giraffe.
c) confirm, based on the above proper studies, that this hybridisation has been recorded on the Laikipia Plateau.
Since it is the current taxonomic view that the Laikipia region is in a zone of hybridisation between the above two species, would you agree that it would be scientifically incorrect to identify observations in this region as anything other than such interspecific hybrids, given that some of the photos posted by iNaturalists themselves confirm signs of the hybridisation?
I would urge iNaturalists to take this matter seriously, because Giraffa reticulata is a threatened species. Its survival is likely to be jeopardised by a careless conflation of the species with hybrids that cannot ultimately contribute to the conservation of G. reticulata, and are currently detracting from the conservation of this species. The particular mechanism of detraction is the inflation of the apparent total number of individuals remaining, which obscures the real precariousness of the species and encourages false complacency.
I'm afraid you may not have understood what I wrote before correctly. I do not question the latest taxonomic revision of giraffes. That's why I repeat my words ... No matter what taxonomic division we prefer (whether reticulata and rothschildi are separate species or just subspecies) .... In this context, however, I recommend looking at the latest research https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7018015/ This latest revision divides giraffes into 3 species, while a 2016 study (Fennesy et al.) Accepted four species. Unlike Groves (2011), both of these studies are much more accurate detailed, and include a huge number of samples across Africa, not just samples and measurements from museums.
Regarding the confirmation of hybridization in Laikipia, Groves & Grubb (2011) only cite that ... Intermediates between G. reticulata and what the authors referred to as G. rothschildi were seen on the Laikipia Plateau, “along the Maralal– Rumuruti Road , ”And between Rumuruti to the S and the Loroghi Plateau to the N, as far as the desert 24 km SE of the S tip of Lake Turkana, and“ east to the dry bed of the Barsaloi River. ” That is, they cite the entries of Stott (1959) and Stott and Selsor (1981). However, this is not a comprehensive survey of the entire population in Laikipia, and not from present. Observation records only. Therefore, it is clear that the current population may not be fully hybrid. It needs to be subjected to research that includes as many samples as possible from all populations in Laikipia. Only then will it be possible to establish the hypothesis to what extent and for which subpopulations within Laikipia these are real hybrids.
And finally as to the signs of the hybridization. This is one thing, but one must not forget the other fact that the long-term isolation of small populations has led to a degradation of genetics over the years, or in other words, a weakening of the genetic pool. This can also result in small or large change in colorations. Therefore, it is important to distinguish in populations which groups of animals show signs of hybridism and which color changes due to isolation. From my point of view, I have nothing more to say on this issue. It's just my opinion as an individual. Try to contact the people who study taxonomy of giraffes. However, I don't think it would be appropriate to introduce iNaturalist users to the belief that all the giraffes they observe in the Laikipia area are automatically without a deeper examination result to hybrids. I repeat, it is necessary to examine this fundamentally first.
@michalsloviak Many thanks for your further views. Perhaps where you and I disagree is on the matter of where onus and parsimony lie.
There is a chance that the population in the Laikipia region is hybridised, and there is a chance that it is not. Let us imagine, for the sake of argument, that the chances are 50/50. Where the onus should lie, to my mind, is according to the principles of risk-management.
Classifying this population as hybridised would, to my mind, incur less risk than classifying it as true. This is mainly because:
classification as hybridised would not much diminish the prospects of conserving reticulata if hybridisation turns out to be a false alarm, whereas
classification as true (= the current classification) would greatly diminish the prospects of conserving reticulata if the reality turns out to be one of hybridisation.
According to this rationale, the onus falls on those who claim true reticulata to prove their case; it does not fall on those who claim hybrid status.
In addition, the following considerations apply:
a) even if you are right that the deviations, seen in the Laikipia region, from the true phenotype (seen in the Samburu and associated regions to the east) are the result of inbreeding/genetic drift, this is still a red flag for the conservation of reticulata;
b) even if only some of the individuals, on only some of the properties, in the Laikipia region have been compromised by hybridisation, this will tend to spread within this region over time, unless the problem is flagged;
c) the Laikipia region has a mesic climate, rainier than the semi-arid climate of the Samburu and associated regions to the east; in this sense it is not typical habitat for reticulata - which means that an assumption of hybridisation is the more parsimonious choice; and
d) I have examined the various populations called 'reticulata' in the zoos of the world, and most of them, too, seem to be hybrids between camelopardalis and reticulata; so captive populations cannot be relied on as any last-ditch reserve of true reticulata.
In summary, I recommend that we ask 'which classification requires the fewest assumptions?' (invoking the principle of parsimony) and 'which classification incurs the least risk?' (invoking the principle of onus). As things stand, there seems to be a considerable risk that two-thirds of the remaining population of 'reticulata' will turn out to be worthless for the conservation of this taxon in its true form, and this proportion is likely to grow if the conservancies of the Laikipia region prove more secure in the long term than the national reserves and other government-managed, poorly-defended lands to the east.
Please let us not have it on our heads that the next generation risks waking up to a sad irony in which the true reticulata has disappeared even as the falsely-named (hybridised and/or inbred) reticulata survives in the Laikipia region and in zoos.
I make this argument with only one goal in mind: saving reticulata, in its true form, from extinction.
The following is one of the best I have seen in illustration of the giraffe of the Laikipia region and its failure to conform with Giraffa reticulata: https://www.istockphoto.com/photo/reticulated-giraffe-gm144800217-4632096.
The following is a particularly clear example of the occurrence of hybrids in the Laikipia region: https://www.alamy.com/african-lion-panthera-leo-sub-adults-approaching-reticulated-giraffe-giraffa-reticulata-group-solio-game-reserve-kenya-image208871670.html. Solio Ranch is situated at the southeastern edge of the Laikipia region (https://en.wikipedia.org/wiki/Solio_Ranch).
Dear All,
@milewski, @michalsloviak
Just my two cents:
There are some preassumptions in your statements that I would like to draw attention to.
Milewski seems to take a very typological approach to conservation that easily can lead beyond efforts of conserving phenotypes of natural populations with equal measure. There is no evidence that the most characteristic looking of any populations of Reticulated Giraffes are also the most natural/original/ancient or more protection-worthy than less extreme phenotypes. They may just be a nice looking local variation among equals.
Both Milewski and Michal Sloviak are arguing on the base of the assumption that historically there must have been either a relatively high degree of natural geographical isolation between camelopardalis and reticulata in the Laikipia area or a time of sympatry (with occasional drought or rain induced migrations into this area perhaps).
I would like to introduce a third possible scenario into the discussion: What appear to be phenotypic hybrids may be part of a natural population that existed in a very similar fashion even before the area became farmland. They might not be a detriment to conservation and instead act and thrive as a well balanced buffer between rothschildii and reticulata phenotypes. It would further be difficult to exclude that such an intermidiate phenotype and adaptation may even have preceded the classical phenotypes of rothschildii and reticulata.
As an intermediate population (hybrid or not) it might always have been better or equally well adapted to the local environment as your typical camelopardalis or reticulata are to their respective center of distribution.
Efforts to conserve reticulata-phenotypes in this area might therefore unnaturally favour one phenotype over the other(s).
I do not know enough about the history of Giraffes in this area. Therefore I'd be happy if you two could address my proposed scenario.
Personally this matter has been of interest to me since 1988 or 1990 when I found a postcard at a lake Naivasha-/Aberdare-/or Mt.Kenya-bookstore that showed a very densly and dark spotted Reticulated Giraffe that neither fitted Baringo-rothschildii-phenotype nor reticulata. I then assumed that this must have represented a phenotype from NW of the Aberdares/Mount Kenya (maybe Mt. Kenya was visible in the backdrop?) and hypothesised a natural zone of transition but did not follow the subject and only much later heard about managed farmland and managed wildlife in this area.
Thanks for any feedback, Cornelius
@capracornelius
Many thanks for your contribution to the discussion. For my reply, please see https://www.youtube.com/watch?v=9P0WAnZZrog.
@dejong
Dear Yvonne, could you please comment on https://www.youtube.com/watch?v=9P0WAnZZrog?
With regards from Antoni
Thanks for pointing out your podcast, sounds very interesting and I will listen to it once i have a bit of time :)
Añade un comentario