Sanbona Wildlife Reserve, often referred to as one of the Western Cape’s best safari experiences, is currently experiencing severe drought conditions. The dictionary defines a drought as ‘a prolonged period of abnormally low rainfall, leading to a shortage of water.’

The word DROUGHT has been a hot topic of discussion across South Africa over the past few years, but what exactly causes a drought?  Changes in temperature, air circulation and weather patterns cause drought. As temperatures increase, more and more water evaporates creating more and more severe weather conditions.   Prolonged shortages in the water supply, whether through below-average rainfalls or decreases in surface water or ground water, can ensure that a drought lasts for anything from 15 days to months or years, as is the case at Sanbona.

Sanbona last experienced proper rain in 2015, when the Bellair dam overflowed. Since then, the yearly rainfall has slowly dwindled and in 2018 the lowest rainfall figures were recorded in the history of Sanbona. Light rain fell in February, June and September this year but still much less than over the surrounding areas.

AVERAGE RAINFALL


NORTHERN SECTION
Succulent Karoo


SOUTHERN SECTION
Renosterveld


DATA COLLECTED BETWEEN 2006 and 2019


164mm


270mm


RAINFALL OVER THE PAST 4 YEARS


100mm


150mm


The Warmwaterberg Mountains bisect the reserve into north and south sections, creating a rain shadow effect trapping clouds mainly on one side of the mountain – ultimately creating more severe conditions.  This bisection has also created two globally recognised biodiversity hotspots or biomes.

WHAT IS A BIOME?

A biome is a large area of land that is classified according to the climate, the plants and animals that make their homes there. The biomes on Sanbona are mainly due to soil type and rainfall.

At Sanbona the two biomes are the Succulent Karoo and Fynbos biomes, with the Fynbos biome splitting further into Renosterbos, which is the predominant fynbos in the southern part of the reserve.

HOW DOES THE DROUGHT AFFECT THE PLANTS AND ANIMALS?

Succulents, with their limited storage capacity and shallow root systems – which also form a large part of the Succulent Karoo – are very successful in predictable rainfall environments, but they are highly sensitive to periodic droughts. This can cause a high turnover and fragmentation in the populations. Prolonged droughts are rare within this biome but can cause a large number of plants to die.  But, many of the plants have also adapted to dry conditions, and to save moisture retreat into a dormant state. They lose all their leaves to prevent moisture loss, but it also means that they cannot photosynthesis and grow. However, as soon as rainfall occurs [it can be as little as 10mm], it transforms them into colourful plants.  See image below: Karoo Gold or Rhigozum obovatum. Most of the time it resembles a dead bunch of twigs yet after a rainfall event they blossom into the most spectacular display of gold and green.

The animals are dependent on the plants so when the plants are dormant or dying, they then suffer too. No drought is without it’s loses and as with nature, only the strong tend to survive.

While compiling this blog, we received a very welcome surprise on the weekend of 14 December 2019. See video1 and video2 here