By Charlie Self
this issue of Cave and Karst Science has an inter-disciplinary feel, with a mix of six papers covering a wide range of cave science subjects. The Forum section contains abstracts of the March 2011 Cave Science Symposium held in Cardiff.
This cave history paper is also an example of how conservation policy can go wrong. During the late 19th century, local farmers unofficially extracted bat guano on a small scale from this well-known tourist cave. Officially, the cave and its guano belonged to the Cape Colony government. In 1895, with increasing demand for fertiliser, the caretaker of the cave wrote to ask for official permission to mine the guano. This was refused in a letter stating that the policy of the government was to preserve the natural features of this public property.
So matters rested until 1920 when Ockert Swart, a nurseryman who didn't even live in the district, began a single-minded campaign to exploit the guano, even writing to the prime minister in 1921 begging for his intervention. He was rebuffed, but later that year management of the cave was devolved to the local municipality. These local councillors regarded the cave as an asset to be exploited for the benefit of ratepayers, and quickly agreed a price for the guano. Chemical analysis proved that the guano was of poor quality and Swart refused to pay the price asked. This forced a lengthy council debate, but no change of price. Nevertheless, mining began in 1921 and continued until 1938, providing a steady but pathetically small income to the municipality.
Cave history papers are not only concerned with the past; once in a while a paper reminds us of Santayana's warning, "…. those who cannot remember the past are condemned to repeat it". Many important caves around the world are currently protected by law, but this can change; ultimately their protection depends on our own vigilance.
This short report offers an introduction to an impressive multi-level, multiple entrance cave system in Hubei province, China. Though fragmented, the system stretches for 10km in a west-east direction and is one of the longest in China. Tenglong Dong has a powerful underground river, large fossil galleries and one part that is a showcave. The local government has applied for geopark status for the region, for both the economic benefit and environmental protection this would bring, assisted in this by members of the British China Caves Project who visited the province in 2006.
Most of the limestone plateaus in the Yorkshire Dales lie at altitudes close to 400m. This prompted the famous geographer Marjorie Sweeting to publish a paper in 1950, claiming that these were the remnants of a peneplain - an old erosion surface from a time when the land was at or near sea level. The paper and the '1300-foot surface' concept became well known, despite doubts from some geologists.
We now believe that the famous and extensive limestone pavements of the Yorkshire Dales are stratimorphs (where weak rock strata have been stripped away by erosion down to the top of a strong rock bed). Smaller versions of these on sloping hillsides are known as structural benches.
In this paper, Waltham and Long have made a detailed study of all the places Sweeting claimed as her '1300 foot surface'. Most are stratimorphs or structural benches, while some are glacial deposits that happen to sit at the required altitude. Elsewhere, the supposed erosion surface is not recognizable in the field and Sweeting may have been misled by contour maps that were less accurate than modern maps. There could be an erosion surface within the Malham Tarn basin but if so, this is a purely local feature.
Science is always re-examining and re-interpreting itself. Sweeting's paper was a classic of its time and although her '1300 foot surface' concept was wrong, the limestone pavements and structural benches of the Yorkshire Dales are still there to be seen … and now we know what they are!
The Mekong delta forms a wide alluvial plain in southern Cambodia and Vietnam. Protruding through the sediments are isolated hills made of granite and, towards the coast, smaller limestone hills. The granite hills contain two types of cave - the first are open joints that have formed by stress relief; the second are extensive mazes within hillside boulder fields. The limestone hills also contain two types of cave - the first are vertical rifts formed by infiltrating rainwater; the second comprise active and relict stream passages at, or just above, the base level of the plain.
The caves are generally small and not particularly extensive. However, they are of considerable local interest for their speleobiology, archaeology, and cultural heritage: some are places of worship, while others were once used as secret military bases. The delta sediments themselves can only tell us about geography changes of the last 8,000 years, but both hills and caves have the potential to provide information about regional landscape evolution over a much longer timescale. The deep weathering of the granite hills shows them to be of great age, while basal notches on limestone cliffs and multiple levels in the horizontal limestone caves may be indicators of former sea levels. It is not yet known whether these changes in base level/sea level relate to the present phase of deposition in the delta, or to a much older phase. This is an interesting preliminary study.
This is a necessarily specialist report on the aquatic invertebrate animals living in a Mendip cave. Most of the cave water derives from a sinking stream, which was sampled just outside the entrance and at a further eight places along the cave streamway. Five other sites were sampled within the cave where small inlet streams derive from percolation water.
The results from the mainstream sampling sites were uncontroversial. The overwhelming majority of the invertebrates caught in the cave streamway were stygoxenes (animals that normally live above ground, but can survive after being washed into caves). The others were stygophiles (animals who live equally well above ground or in caves). No stygobites (animals who live only in caves) were found in the mainstream.
The percolation water streams proved to be much poorer in terms of the total number of animals caught, as well as in the number of taxa (groups/ types of animal). However, three species of stygobitic crustacean were recorded, with one species being the first confirmed occurrence in the UK.
These results represent only the second systematic survey for freshwater invertebrates in a British cave, and the first in a region that was not glaciated during the last 'Ice Age'. When the results are combined with those from earlier studies, Swildon's Hole appears to be a particularly rich site, both in total numbers and in biodiversity. However, if a similar systematic survey were to be made in another Mendip cave, the author predicts similar findings. Clearly much more work needs to be done on the ecology of British caves.
During a surveying trip, a small section of new cave was entered by excavating up through a boulder choke. The new passage led to the edge of a much larger choke, where part of a red deer antler was found. On subsequent trips, more bones were discovered; domestic dog and cow, wild auroch (an extinct species of ox) and part of a human tibia. Radiocarbon dating of the human bone gave a middle Neolithic (New Stone Age) date, consistent with an assemblage containing both wild and domestic animals. Further digging linked the new passage back into a known part of the cave.