Quiver Tree deaths in Augrabies

[DerickOosthuizen]

Hallo all,

My wife and I visited the Augrabies Nat Park during April 2015 and noticed the "high percentage" of Quiver Tree deaths.

Does anybody know:
What the reason(s) is for these deaths?
What the estimate percentage is to date and
When the deaths has started?

Kind regards

Derick Oosthuizen

[George_Brits]

Hi Derick,

To answer your question regarding the dead quiver trees at Augrabies...

Remember that these trees can grow as old as 350 years, but, quiver trees have been negatively impacted by climate change over the decades. An increase in the average temperature of the region where quiver trees thrive have caused the population to decline.

Masses of quiver trees have died as a result of droughts.

Plants species can adapt to temperature changes by shifting their ranges, but members that do not make this shift will usually not be able to reproduce and will die, contributing to the death of some quiver trees.

Animals have also caused damage to the quiver trees through gnawing and various other uses of the trees such as for shelter and food. A disease known as aloe rust can threaten quiver trees as well.

I hope this partially answers your question

[barryels]

DerickOosthuizen,

I have send your request to SANParks PR for a reply .

[NadiaL]

Hi Derick,

I've approached Dr Hugo Bezuidenhout - Scientific services to answer your questions.

HB: Dear Mr Oosthuizen thank you for your observations and questions. We appreciate the communication.
We are not sure where in the Park you have seen this “high percentage” dead Quiver trees? Quiver (Aloe dichotoma) trees occur in the “Swartrante”, on the granite undulating plains as well as on rocky outcrops of the Park. They are sparsely distributed and common through the midslopes landscapes of Augrabies Falls National Park (AFNP), in some places they tend to grow closer together but unfortunately in AFNP we are not so lucky to have a woodland of them standing together as in the case of Niewoudtsville and near Onseepkans.

Reason for these deaths: a number of factors – age is one, sometimes they get a disease which is not good for their health condition, and then maybe a dry or too wet spell let them die. Sometimes the baboons eat the nectar of the flowers and the baboons break their stems and this also is to the detriment of the health of the trees. This make the tree more susceptible for diseases. We also have giraffes in the Park, which also sometimes, as well as, porcupine damage these plant species. We have erected a fence (total exclusion plot for wildlife) around some of the quiver trees and we have a monitoring programme to monitor the quiver trees which is one of the iconic trees for AFNP. Since 2009 we have started noticing some quiver trees that die but some of them was very old and thus part of the natural processes. In total for AFNP the estimated deaths for quiver trees I would estimate on about 5 % of the total Parks quiver tree population. There is still good generations of young ones coming through which is good to see.

I trust this will assist you with your questions. Regards,