Caves and bats: Morphological impacts and archaeological implications. The Azé Prehistoric Cave (Saône-et-Loire, France)

Barriquand, Lionel; Bigot, Jean-Yves; Audra, Philippe; Cailhol, Didier; Gauchon, Christophe; Heresanu, Vasile; Jaillet, Stéphane; Vanara, Nathalie

doi:10.1016/j.geomorph.2021.107785

Cited by 8 publications

(5 citation statements)

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“…59 – 63 ]. Bats and their guano may influence cave development processes in different ways ( Fig 7 ): i) thermically, because the body heat emanated by thousands of individuals and the decomposition of large guano deposits they produce may increase the cave temperature in several degrees; ii) climatically, when the water in bats´ respiration can saturate the ambient air and may condense, covering parts of the cave surface with a film of water; and iii) physicochemically, when the CO 2 and urea released by bats´ respiration and urine, respectively, reacts with other chemical compounds in the cave, leading to other physicochemical reactions [ 64 ].…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, in that cave it is conceivable that some stalagmites, pillars, and stalagmitic floors buried under several meters of guano have completely disappeared as a result of corrosion due to the acidity of the deposit. In the Azé limestone cave, in France, where Myotis daubentonii bats are present for more than 54 ka, a calcite flowstone 22 ka ago isolated part of the cave, preventing access and entry of bats in part of that cave [ 64 ]. That allowed researchers to better understand the role bats and their guano had on the cave´s morphological changes: in the area inaccessible to bats, cave walls were hardly altered, whereas the parts available for bats experienced the formation of cupolas on the ceiling, which resulted in an upward expansion of the cave’s volume, with an estimated retreat of the walls and speleothems of ~3 to 7 mm/ka [ 64 ].…”

Section: Discussionmentioning

confidence: 99%

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Bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia

Piló

Calux²,

Scherer³

et al. 2023

PLoS ONE

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Ecosystem engineers are organisms able to modify their environment by changing the distribution of materials and energy, with effects on biotic and abiotic ecosystem components. Several ecosystem engineers are known, but for most of them the mechanisms behind their influence are poorly known. We detail the role of bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia, an area with > 1,500 caves, some holding ~150,000 bats. We analyzed the chemical composition of guano deposits in bat caves, radiocarbon-dated those deposits, and elucidated the chemical mechanisms involved and the role the bat guano has on modifying those caves. The insect-composed guano was rich in organic matter, with high concentrations of carbon, nitrogen, phosphorus pentoxide and ferric oxide, plus potassium oxide, calcium and sulfur trioxide. Radiocarbon dating indicated guano deposits between 22,000 and 1,800 years old. The guano pH was mainly acid (from 2.1 to 5.6). Percolating waters in those bat caves were also acid (pH reaching 1.5), with the presence of phosphate, iron, calcium, nitrate and sulfate. Acid solutions due to guano decomposition and possible microbial activity produced various forms of corrosion on the caves´ floor and walls, resulting in their enlargement. Bat caves or caves with evidence of inactive bat colonies had, on average, lengths six times larger, areas five times larger, and volumes five times bigger than the regional average, plus more abundant, diversified and bigger speleothems when compared with other caves. In an example of bioengineering, the long-term presence of bats (> 22,000 years) and the guano deposits they produce, mediated by biological and chemical interactions over millennia, resulted in very unique ecological, evolutionary and geomorphological processes, whose working are just beginning to be better understood by science. However, the current expansion of mineral extraction activities coupled with the loosening of licensing and cave protection rules is a real conservation threat to the bat caves in Carajás. The destruction of those caves would represent an unacceptable loss of both speleological and biological heritage and we urge that, whenever they occur, bat caves and their colonies must be fully protected and left off-limits of mineral extraction.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia

Piló

Calux²,

Scherer³

et al. 2023

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…Bats and their guano may influence cave development processes in different ways (Fig. 7): i) thermically, because the body heat emanated by thousands of individuals and the decomposition of large guano deposits they produce may increase the cave temperature in several degrees; ii) climatically, when the water in batś respiration can saturate the ambient air and may condense, covering parts of the cave surface with a film of water; and iii) physicochemically, when the CO 2 and urea released by batś respiration and urine, respectively, reacts with other chemical compounds in the cave, leading to other physicochemical reactions [59].…”

Section: Discussionmentioning

confidence: 99%

“…and iii) physicochemically, when the CO 2 and urea released by bats´ respiration and urine, respectively, reacts with other chemical compounds in the cave, leading to other physicochemical reactions [59]. Figure 7.…”

Section: Bats and Biogenic Corrosion In Caves -Operating Mechanismsmentioning

confidence: 99%

“…Moreover, in that cave it is conceivable that some stalagmites, pillars, and stalagmitic floors buried under several meters of guano have completely disappeared as a result of corrosion due to the acidity of the deposit. In the Azé limestone cave, in France, where Myotis daubentonii bats are present for more than 54 ka, a calcite flowstone 22 ka ago isolated part of the cave, preventing access and entry of bats in part of that cave [59]. That allowed researchers to better understand the role bats and their guano had on the cave´s morphological changes: in the area inaccessible to bats, cave walls were hardly altered, whereas the parts available for bats experienced the formation of cupolas on the ceiling, which resulted in an upward expansion of the cave's volume, with an estimated retreat of the walls and speleothems of ~3 to 7 mm/ka [59].…”

Section: Long-term Effects Of Bat Presence In Cavesmentioning

confidence: 99%

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Bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia

Piló

Calux²,

Scherer³

et al. 2022

Preprint

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Ecosystem engineers are organisms able to modify their environment by changing the distribution of materials and energy, with effects on biotic and abiotic ecosystem components. Several ecosystem engineers are known, but for most of them the mechanisms behind their influence are poorly known. We detail the role of bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia, an area with > 1,500 caves, some holding ∼150,000 bats. We analyzed the chemical composition of guano deposits in bat caves, radiocarbon-dated those deposits, and elucidated the chemical mechanisms involved and the role the bat guano has on structuring those caves. The insect-composed guano was rich in organic matter, with high concentrations of carbon, nitrogen, phosphorus pentoxide and ferric oxide, plus potassium oxide, calcium and sulfur trioxide. Radiocarbon dating indicated guano deposits between 22,000 and 1,800 years old. The guano pH was mainly acid (from 2.1 to 5.6). Percolating waters in those bat caves were also acid (pH reaching 1.5), with the presence of phosphate, iron, calcium, nitrate and sulfate. Acid solutions due to guano decomposition and possible microbial activity produced various forms of corrosion on the caveś floor and walls, resulting in their enlargement. Caves with active or inactive bat colonies had, on average, horizontal projections 4.5 times larger, areas 4.4 times larger, and volumes 5.0 times bigger than the reginal average, plus more abundant, diversified and bigger speleothems. In an example of bioengineering, the long-term presence of bats (> 22,000 years) and the guano deposits they produce, mediated by biological and chemical interactions along millennia, resulted in very unique ecological, evolutionary and geomorphological processes, whose working are just beginning to be better understood by science. However, the current expansion of mineral activities coupled with the loosening of licensing and cave protection rules is a real conservation threat to the bat caves in Carajás. The destruction of those caves would represent and unacceptable loss of both speleological and biological heritage and we urge that, whenever they occur, bat caves and their colonies must be fully protected and left off-limits of mineral extraction.

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Dissolution of Karst Rocks

2022

Karst Hydrogeology, Geomorphology and Caves

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Caves and bats: Morphological impacts and archaeological implications. The Azé Prehistoric Cave (Saône-et-Loire, France)

Cited by 8 publications

References 27 publications

Bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia

Bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia

Bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia

Dissolution of Karst Rocks

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