What is the secret behind so many endemic species in Kerala ?:
While browsing through Flora of Peninsular India, I generally found that Kerala is having so many endemics (including narrow endemics with distribution shown in only one place or district) compared to other states like Tamil Nadu and Karnataka etc.
What can be the reason behind it ?


Unique habitats like Agasthiyamala biosphere, silent valley, Anaimalai with evergreen forest. Another important thing is keen observation on the flora, several taxonomic experts also available in Kerala. Species present in the North east are also available here because of similar climatic conditions.


The question ” What is the secret behind so many endemic species in Kerala? ” raised by … has several answers. The first reason has been very well explained by … Secondly, the flora of Kerala has been well explored and documented and every part of the state has been thoroughly explored and the important findings were published in time. There are certain exceptions that  a few new gen botanists described the already known species in many foreign journals as new species again. Sadly in several cases the reviewers never known about it. In the recent climatic change scenario, several ephemerals become annuals or biennials or even perennials through several perennating mechanism. Such species often mistakenly described new during recent times from Kerala. Genera such as Impatiens, Sonerila, Strobilanthes etc are having several species grow together in a biome often have a chance of exchange genes by  interbreeding between them. The F1 generation often having characters of both parents and also possessing certain unique characters of themselves. It is called Nothospecies. Such characters never having a chance of continue over generations. Some of the new gen botanists described such taxa as novelties to science. There are several hidden agenda behind it. Certain exotic species naturalized in Kerala years ago show several ecological traits also described novelties recently. Unnecessary addition of fictitious novelties increased the number of endemics in Kerala. I have prepared a list of  such ‘paper species’, but wont like to publish in such a public forum. Let some experts in respective fields should tackle the issue.


You have explained the things so well.


I somehow have the feeling that only one out of the 10 species published currently, may stand the scrutiny of time and remain as a valid species and not relegated as a synonym.
I do not know how others feel about it. Hard core taxonomists may give a better estimate.


Yes …, this is what I too felt nowadays


In the past 10 years in Hong Kong, I have merged around 35 new and old species names into existing ones. Imagine, so much work to do. I already have a new list for my next publication. Achievement of a taxonomist is not just publishing new species but also correcting the existing ones.


I also think that is much more important.
Revisionary studies with deep study of a genus with thousands of specimens and hundreds of original literatures/ publications, are much more important.
It may certainly involve many many years of ones’ productive life.


Please also remember that this issue is not just in Indian plants. I see more in Chinese plants actually !!!


Enjoying the discussion!


Quite a learning through this post, and many angles have been presented through the experienced Botanists..
Of course, the habitat specialty is one aspect, but a thorough exploration of the region is to be given credit…
If a mapping or proportionating can be done w.r.t. number of active field workers available per unit land area, southern parts of our country may be well ahead, I think…
Thanks … for this interesting query…


Your are most experienced among us. What do you think?


The amount of complicated montane forest ecosystems are probably higher there and they receive more rains also…Some other climatic and other factors may be responsible for this such as extensive explorations. However,  some recent mergers suggest that the actual number of taxa might be somewhat inflated!


For me things are not that straightforward, comparing new species with endemics. A newly described species over a period of time may be discovered in neighbouring areas also, or merged with already known species from surrounding areas, it is only that author first describes it from a particular region. An endemic on the other hand may have arisen recently (through mutations, or crossing followed by duplication of chromosomes, since hybrids of most diploid species are sterile and perish very soon, unless maintained by vegetative means) and did not get get enough time to spread to similar surrounding areas (neoendemics), or widely spread once but getting restricted due to shrinking of their habitats (Palaeoendemics).


I really appreciate your knowledge on Indian flora and its distribution. It was a fine and apt observation based inquiry on endemism in flora of Kerala.

See the number of taxa (mainly species) endemic to different states of India based on the document by Botanical Survey of India (Endemic Vascular Plants of India by Singh et al. 2015) below:

State Narrow endemic Taxa (No) State Narrow endemic Taxa (No)
Tamil Nadu 410 Himachal Pradesh 28
Kerala  (38,683 km2)

1 species/108 km2

357 Uttar Pradesh 26
Maharashtra 278 West Bengal 23
Andaman Islands 201 Odisha 20
Arunachal Pradesh 183 Mizoram 16
Sikkim  (8586 km2) 1sp/54km2 160 Goa 14
Meghalaya 134 Rajasthan 14
Karnataka 130 Madhya Pradesh 12
Assam 87 Bihar 6
Jammu & Kashmir 82 Gujarat 6
Uttarakhand 81 Jharkhand 3
Nicobar Islands 77 Chattisgarh 1
Andhra Pradesh (undivided) 64 Punjab 1
Manipur 45 Tripura 1
Nagaland 35    

Kerala state is located very close to the equator and lies in a tropical zone (zone located between 23.50 north and south of equator) which is considered the richest zone for biodiversity. It is believed that in tropical zones life originated on earth and had maximum time to evolve and diversify with less catastrophic natural disturbances as compared to subtropical, temperate or arctic zones on earth. Here the temperature remains similar throughout the year so it is not a seasonal abundance of plants (as we see in subtropical or temperate zones where high diversity of plants can be seen in summer & rainy season), rather plants flourish throughout the year. In addition, tropics receive a higher amount of solar radiation which is the energy pool driving life on earth. More energy available leads to more productivity and more diversity. A large part of international biodiversity hot-spot “Western Ghats” lies in Kerala where we have a range of mountains clothed with rainforests and blessed with high rainfall. Wherever we have mountains, due to great variability of microhabitats, the diversity of life is high. The species which evolved in tropics were not able to spread in adjacent subtropics due to lack of their climatic requirements in subtropics. The species which evolved in a specific set of microhabitats in tropical mountains remained there as such microhabitats were not available in subtropical mountains.

However, the answer is not so simple and phytogeographers (scientists who study distribution of plants) or ecologists have proposed many theories for richness of biodiversity in world tropics.

This is a useful reading- ecologycenter

In my opinion (off-course with over-simplification) being located in the tropics, having Western Ghat mountains, a lot of rainfall throughout the year and ample exploratory work Kerala has a high number of species and endemic elements.

New species described may get merged into older species with revisionary works but still there will be a large number of species and endemics in flora of Kerala as compared to many Indian states.

In India, as per the information in the above table, Sikkim with just 8586 km2 area has high endemisms- one endemic species for every 54 km2 while Kerala has one endemic species for every 108 km2.

The last word- answer is not simple and there are many known (and also unknown) reasons behind high diversity and endemism in Kerala.


Good question …!

As one of the major biodiversity hotspots of India, the Western Ghats harbors a great species diversity with a high number of endemics. Also, thanks to the active fieldwork and special documentation and exploration programs, many new species are being discovered from previously under- and un-explored areas.

That said, there are concerns as discussed earlier. Another concern is that there is no clear-cut definition of delimiting characters that qualify a new species. Of the two kinds of botanists, the lumpers and splitters, the latter kind mainly contributes to the inflated number of new species. Of course there are exceptions. I documented more than 30 intra- and infra-specific variations from my PhD study area alone but plants with some of these documented variations (such as different flower color, leaf shape) have been recently described as new species by folks even working in reputed institutions. There is a tremendous interest among botanists to publish new taxa. This is fueled in part by the current job offer and promotion settings that credit and support quantity rather than the quality of research publications.
The review and publication process must be strengthened and made transparent. Every journal should require sufficient proof and authenticity of the Type specimens. There are so many predatory journals that publish anything if the processing fee is paid. Young researchers should be made aware of these and papers published in these journals should not be considered when it comes to job offers or promotions. Also, we need many revisioners, and while revising a genus or family the botanists should consider and use the data from various fields of botany such as morphology, anatomy, palynology, photochemistry and molecular biology, with collaborations from international experts.


You have spelled out the hard truth and I agree with your views on the current scenario.


Thank you all for such a valid discussion.
Thank you … for opening this discussion.
I feel that many of the reasons or answers for the question are already covered in previous mails.
I have a few more things to discuss.
Myers et al. (2000) and Mittermier et al. (2011) and several others have explained multidimensional aspects of species endemism.
I am attaching these papers herewith for your perusal.
Few (more) reasons for Kerala having high endemism are:
  • Habitat heterogeneity
  • High frequency of ecotones
  • Micro -habitat and -climate variations.
  • Reduced number of dry months.
  • Geographical characters (for eg. Westward facing geography that is beneficial in getting/tapping maximum light).
  • Diverse edaphic features.
  • The Total geographical area is smaller, resulting in smaller habitats. This might enhance genetic drift as smaller populations help drift and fixation faster.
There may be other reasons too.
Thanks …. for speaking some eye openers.
You are absolutely right even ecotypes and ecads are also treated to be species discoveries.
I have seen several colour and size variations in the same individual plants (of several species) across years during my phenology observations.
Further, if a plant flowers in a different season, it may show some variations.
This might be related to variation in the climate or local micro habitat characteristics.
As … mentioned, habitat variation is a general fact for tropical parts of the world, which is proved by several studies. Most such studies are from elsewhere, unfortunately, there are not many studies from our regions.
Kerala is blessed with several taxonomists across various time periods and we have few institutes and centres dedicated for taxonomy.
Several species have been published with only one sighting and the majority of these new species do not have any further references in any later studies or inventories.
No further evaluation, observation, or sightings about the majority of the newly published ‘species’.
Further, as … rightly pointed out, there are no set standards to call a plant a new species.
2 attachments.


As regards parameters of determining a new species, this procedure cannot be standardized at all. I wrote these lines somewhere:

Only an experienced taxonomist expertising on a particular group can give a sound judgement on delimitation. From numerical taxonomy, through cladistics we are now in the era of molecular phylogenetics. Therefore, the conclusions on morphological (both external and internal) should now be corroborated with molecular studies. The delimiting characters vary from group to group, e.g. a single inflorescence type delimits the family Compositae but a combination of characters determine some others.  Only an expert/monographer rather than a random taxonomist/floristics worker can give a sound judgement. Moreover, you cannot standardize the taxonomic characters through mathematical formulae and statistical analysis and apply them for delimitation for stabilizing the nomenclature. You must depend on expert opinion only for delimitation of genera and infrageneric taxa.


My comments may kindly be taken as a pure scientific discussion. I apologise if I have hurt sentiments of someone by using some harsh words. In fact we are noticing random new descriptions by some persons in each and every group. The Plant Discoveries published by BSI is documenting such publications in India but there is no comprehensive publication consolidating the nomenclatural changes including mergers in Indian perspective. POWO, to some extent, tries to keep the nomenclature up to date in relation to IPNI but it has own limitations. So, we at eFI should try to keep our database most up to date, as far as possible. This will further enhance the grandeur of the group.


Last year I had an opportunity to talk to … of Uppasala Universty, while discussing of Boswellia ovalifoliolata, he said if it is a true endemic, there must be some other endemic species in the area, then it will not be in association with common species of the area; it is true, in A.P. Seshachalam and Velugonda hills harbours majority of endemics of the state; B.serrata and B.Ovalifolialata are never seen in same vicinity.
thank you for enlightenment and provide a chance to express my observations.


There are two aspects of this discussion here:

1. Taxonomy and new species: One of our valued members said that it needs good expertise to publish a new species and only experienced taxonomists can give a sound judgement. I actually think the opposite of this. Only a good taxonomist can do good taxonomy- I agree. But only a good taxonomist misuses taxonomy to publish such silly new species. People who have no idea about taxonomy cannot publish a taxonomic paper.
2. The diversity in Western Ghats: Undoubtedly, western ghats has high diversity and with respect to Kerala, looking at the terrain and precipitation patterns there is very high habitat heterogeneity too. Hence the chances of finding interesting diverse group of plants are higher.

Just my personal thoughts.


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