Disjunct Distribution and the Sun Bird Bush
The word disjunct was not acceptable to my spell check but I know its true because google and Wikipedia are happy with it . Wikipedia has an entry but I am going to rely more on the explanations from A.E van Wyk and G.F Smith’s book Regions of Floristic Endemism in Southern Africa. Reason number one is it is a superb book and two it makes it look like I did more research for this blog entry.
Disjunct distribution is where two or more populations of a taxon are exceptionally widely separated geographically.
A good example of a disjunct distribution is one right on my doorstep probably about 2 km’s from where I am typing this in the Krantzkloof Nature Reserve, Durban. In 2000 David Styles and Rod Edwards discovered a population of a plant known as Metarungia pubinervia ( Sun Bird Bush ) in the reserve. Prior to this discovery the species was known only to occur in Central Africa and more recently North Africa. A remarkable distribution.
Was the species much more widely distributed in the past but because of major climate changes or loss of habitat it now only survives in these separate sites? Or is the population in Krantzkloof the result of a founder population through exceptional long range dispersal?
David Style showed me one population and the landscape shot below was taken very close to this. The plant has, thanks to the efforts of Geoff Nichols, become popular in gardens in and around Durban and rightly so.The common name , Sun Bird Bush, is an apt name as this bush is much loved by Sun Birds. This makes it a great addition to a Wild Garden.
How many more discoveries like the above are waiting out there? Krantzkloof Nature Reserve is well explored but even in this Nature Reserve, surrounded by development on all sides and situated centrally in the Durban Municipal area, new discoveries are being made. I have to believe that in the other less explored areas of Kwa Zulu Natal there are many new discoveries to be made.