Kogelbeen Cave

The Kogelbeen Cave forms part of eight caves on the dolomitic Ghaap Plateau of the Northern Cape, South Africa. It is commonly known as Kogelbeengrotte by Afrikaans speaking community members. The cave is located on Kogelbeen Farm in Pixley ka Seme District Municipality. It is the longest known cave in the Northern Cape with a length of 788 meters. The Kogelbeen Cave has a diverse fauna with over 39 species living in five life zones within the cave.

History

The cave was first described in speleological literature in 1964. The cave is classified as a South African Natural Heritage Site under the South African Natural Heritage programme

Surveys and explorations

Irish and Marais survey

The total cave length was measured at 788 meters. The cave entrance was measured with a 90m x 30m doline which lead to a 30m x 15m sinkhole. The floor slopes at a depth of just less than 8m. The doline walls have some holes however, the main site of the cave starts at the deepest and southern part of the doline. The Dry Passage is a short and dusky section above the entrance on two levels, which leads for 70m in an eastward direction. There is a collapsing overhang to the north of the cave. The main cave sharply descends to a small chamber which is approximately 22m. Along the north wall of the main chamber is a small hole in the floor. This hole leads to a narrow and moist passage known as the CO₂ passage. In this passage, lethal CO₂ levels are reached after penetration of a depth of 43M. These lethal levels of CO₂ prevented further exploration. The main cave continues into a main chamber which is approximately at 31M. Southeast of the main chamber lies a long passage called the Bat Passage, which slopes upwards for about 120m. There are a few minor parallel passages linking with the Bat Passage. The passage has a very high ceiling which is more prominent towards the end of the passage. Westward of the main chamber lies a small crawlway which leads to a low and wide passage called the Water Passage. The Water passage is filled with numerous shallow seepage pools. The water table is reached at 57m.

Hitchcock survey

The 1980 Hitchcock survey differs from the Irish & Marais Survey with regards to the CO₂ passage. Hitchcock penetrated the CO₂ passage all the way to the water table, but makes no mention of the lethal carbon dioxide levels. The air composition is described as, 'the air was very good'. Hitcock measured the water table level in the Water Passage at 53m unlike the 57m measured from the Irish and Marais Survey. The water level in the CO₂ passage is measured at 73m.

The current lethal CO₂ levels make it near impossible to confirm Hitchcocks measurements of the carbon dioxide passage.

Climate

The main chamber has a temperature of 19 degrees Celsius, the temperature rises to 21° Celsius in the Bat Passage and ultimately 22° Celsius in the water passage. The relative humidity in the Water Passage and the Bat Passage reaches 100%. The humidity drops to 98% in the Main Chamber and 80% in the Entrance Passage. The water temperature of the main pool is 21° Celsius. Subjective commentary on the carbon dioxide levels over time indicate an increase in CO₂ over the past two decades. Hitchcock reported no CO₂ levels after penetrating both the Water Passage and the Carbon Dioxide Passage in 1980. Irish and Marais reported high CO₂ in the Water Passage and lethal CO₂ presence in the CO₂ passage in 1991. The survey in 1997 found the Water Passage to be even more uncomfortable with the high CO₂ composition of the air and the CO₂ passage impossible to survey.

Life zones

There are 5 life zones in the cave that are distinguishable namely: 1. The entrance zone includes the doline as well as the twilight cave areas (seven taxa) 2. The dark dry zone includes the Dry Passage ( nine taxa) 3. The wet zone includes the Main Passage, Water Passage and Bat Passage (twenty four taxa) 4. The CO₂ zone includes the CO₂ passage (two taxa) 5. The aquatic zone includes the groundwater pools and one taxon

Biospeleology

Animals found using the doline and entrance of the Kogelbeen Cave include:

• baboon Papio ursinus
• hyrax Procavia capensis
• porcupine Hystrix africaeaustralis
• rock pigeons Columbia guinea
• palewinged starlings Onchognathus nabouroup
• barn owls Tyto alba
• frogs Cacosternum boettgeri
• opilionid spider Polycoryphus asper

Baboons that are found at the entrance of the Kogelbeen Cave

Barn Owls found in the cave

The doline serves well for moisture loving creatures who would otherwise not survive in other areas of Kogelbeen. The Kogelbeen cave also functions as an important bat roost being home to three bat species, including Miniopterus schreibersii with a population of over 60 000, the Rhinolophus clivosus and the Rhinolophus darlingi, with a combined population of about 5000. Other bat species found include:

• Rhinolophus denti
• Nycteris thebaica
• Myotis tricolor
• Eptesicus capensis
• Tadarida aegyptiaca

The Miniopterus scheibersi bats with a population of over 60 000 in the Kogelbeen Caves

These bats are mostly found in the Main Chamber as well as the Bat passage. Considering the large population of bats, unexpectedly thin guano deposits are found.

Species that are dependent on the guano deposits include:

• a white fungus that grows on the guano as well as bat remains,
• psychodidae flies (Diptera) commonly found in Bat Passage with multitudes of their nematocerous larvae found in wet guano,
• flies including the Camillidae D. barraclough, pers. com and another two unidentifiable species

Detritivores that feed on older guano deposits include:

• isopods Oniscus species as well as small red mites of Uropodidae family.
• Lepidospora species are only found in the carbon dioxide passage,
• crickets (Orthoptera, Gryllidae),
• Ptinidae beetles (Mezium species),
• unidentified Psocoptera,
• Eurycho species Coleptera and Tenebrionidae as well as
• Large hairy catterpillers Lepidoptera larvae

Preditors in the Kogelbeen Cave include:

• A large variety of spiders but mostly Gnaphosidae, Dictynida and other Ariadne species
• Assassin spiders Reduviidae

Parasites in the Kogelbeen cave include the mite of the Argus species Argasidae, which feed on the birds and bats of the cave.

Aquatic Fauna in the cave include stygobiotic amphipod Sternophysinx Basilobata, which is only found from Kogelbeen.

There is a mammal checklist of the species found in the cave at the Bloemfontein National Museum.

Deaths

The community members around the Kogelbeen cave believe that an unspecified person died in the cave. It is believed that there is an unknown disease that exists in the cave. Smith reported that some of the members of his team fell ill due to histoplasmosis. Hitchcocks party used masks as a preventative measure against unknown diseases. No recorded members of the Irish and Marais party were affected by illness from the Kogelbeen cave.

Development potential

Griekwastad publicity association has sought assessments of the cave as a possible tourism area. Factors that result in the cave being unfavourable for tourism include difficulty in movement around the cave, lack of cave formations, the CO₂ conditions are unpleasant in some areas, and threat of disease. Fishing enthusiasts frequently use the areas in the cave for fishing using a man-made outpost structure. Further tourist development would result in a major loss of the bat species thus threaten the rest of the fauna.

See also

• Cango Caves
• Wonderwerk Cave
• Sacred caves of the Basotho
• Boesmansgat

External links

• https://geographic.org/geographic_names/name.php?uni=-1819957&fid=5710&c=south_africa
• Northern Cape Tourism
• NC Provincial Government