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.
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:
|Narrow endemic Taxa (No)
|Narrow endemic Taxa (No)
|Kerala (38,683 km2)
1 species/108 km2
|Sikkim (8586 km2) 1sp/54km2
|Jammu & Kashmir
|Andhra Pradesh (undivided)
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 …!
You have spelled out the hard truth and I agree with your views on the current scenario.
- 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.
As regards parameters of determining a new species, this procedure cannot be standardized at all. I wrote these lines somewhere:
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: