Centres of Endemic?

[Robin Leech]

Norbert,
The word you want is PRECINCTIVE, from Fauna Hawaiiensis, 1900.  You will
find it defined in the Webster's 2nd International Dictionary, but not the
3rd.  You will also find it defined in the OED (Oxford English Dictionary -
the 20 volume set.
ENDEMIC and NATIVE are human related terms, though they are used more or
less synonymously with PRECINCTIVE.
Robin Leech

----- Original Message -----
From: Norbert Hahn <hahn1 at MWEB.CO.ZA>
To: <TAXACOM at USOBI.ORG>
Sent: Monday, November 15, 1999 1:04 PM
Subject: Centres of Endemic?


> Dear All,
>
> I am sitting with a perplexing problem of trying to define the term
"centre
> of endemism"!
> In a biological context, an organism restricted to localised area is
> referred to as an endemic. If this localised area has a high occurrence of
> endemics we generally refer to it as a "centre of endemism". Terrestrial
> Centres of Endemism are most easily understood in the contexts of islands
as
> they are surrounded by the see and as such are relatively isolated. The
> problem comes when one looks at islands in close proximity of one another.
> As an example should one see the Galapagos archipelago as a centre of
> endemism or should one treat every individual island as a separate centre
> interacting with the other centres within the archipelago.
>
> The above argument becomes problematic when one tries to apply the above
> mentioned concepts of centres of endemism on to a continental scale. Our
> fist problem would be to try and ascertain natural boundaries to delineate
> centres of endemism. For example the Cape centre of endemism is well
defined
> as it occurs within the winter rainfall region of southern Africa which in
> turn has created a unique environment known as the fynbos. The problem
comes
> once one enters the summer rainfall regions. As an example, the
Soutpansberg
> centre of endemism is a well-defied geographic area which in turn is well
> delineated by it endemic fauna and flora. The problem comes once one looks
> beyond the so call narrow endemic species (species restricted to the given
> study area). As an example there is a strong interchange of plants between
> the Soutpansberg and Maputaland (van Wyk 1996). Should one consider these
> plants separately from the rest of the flora and thereby define them as
> Soutpansberg-Maputaland endemics. Out of a biological point of view much
can
> be gained from treating these plans separately. They can give us an
> indication to the probable evolution of the set biota. If one excepts the
> Soutpansberg-Maputaland endemics, as separately delineated entitys one
comes
> up with the following perplexing problems. If the given two areas interact
> in similar ways with other centres of endemism, does one define this group
> as an archipelago like concept of endemism such as the Galapagos except
that
> the surrounding areas are terrestrial?
>
> What does one call such an archipelago and where does on draw its borders?
> White (1983) in his Vegetation Map of Africa named a specific floristic
> region the Afromontane Region. He when on to define the Afromontane Region
> as an archipelago-like centre of endemism extending from Lolma Mts. and
the
> Thingi Hills (11° W) in Siera Leone in west Africa to Ahl Mescat Mts (49°
E)
> in Somalia in the east to the Red See Hills (17° N) in the Sudan Rep. in
the
> north to the Cape Peninsula (34° S) in the south. The defining of
floristic
> regions as centres of endemism poses a problem as it excludes geographic
> centres of endemism. The above exampel none the leas it shows that it is
> possible for isolated regions scattered throughout Africa to interact.
>
> What douse one call biological entities which occurs on two or more of
these
> centres. If one had to name these in accordance to their distribution
things
> would become quit interesting. Consider three centres of endemism named A,
B
> and C. The narrow endemics (Ed) would be called, A Ed, B Ed and C Ed, the
> near endemics would be A-B Ed, A-C Ed and B-C Ed and the wide endemic
would
> be A-B-C Ed. This nomenclature equates to a formula of 2^n - 1 = no.
> combinations. As can be seen this type of naming is quit unpractical. To
> name the set entities in context to there floristic association could pose
> an answer. The assigning of floristic elements has one draw back, they are
> mostly based on hypothetical assumptions.
>
> I have been tolling with the above problem for quit some time, all that it
> has brought me was more confusion to unresolved questions.
>
> I am eagerly awaiting you answer or possibly more questions.
>
> Norbert Hahn
> Director ICONS
> P.O. Box 1734
> Louis Trichardt
> 0920, South Africa
> Tel: SA 015-5177176
> E-mail: hahn1 at mweb.co.za
>
> REFERENCES
>
> VAN WYK, A. E. 1996. Biodiversity of the Maputaland Centre. The
Biodiversity
> of African Plants 198-207.
>
> WHITE, F. 1983. The vegetation of Africa. A descriptive memoir to
accompany
> the Unesco/AETFAT/UNSO vegetation map of Africa. Paris: Unesco
>