Observations on the Ecology of Caves


Material Information

Observations on the Ecology of Caves
Series Title:
The American Naturalist
Barr, Thomas C.
The University of Chicago Press
Publication Date:


serial ( sobekcm )


1. The principal energy sources of cave ecosystems are (a) organic matter swept underground by sinking streams, and (b) the feces, eggs, and dead bodies of animals which remain in the cave for shelter but feed outside (trogloxenes). In temperate zone caves flooding and the entrance of cold air during winter and early spring disturb the relatively constant physical conditions of the cave environment. 2. Species density, dispersal potential, and other aspects of the ecology of troglobites (obligate cavernicoles) are profoundly influenced by continuity of limestone outcrops in which the caves are developed. In the Appalachian valley, where limestone is exposed in many narrow, anticlinal strike belts, species density per unit area is high, and dispersal of troglobites through subterranean channels is severely restricted by geologic structure. In the Mississippian plateaus, where thick, caverniferous limestone is widely and continuously exposed, there are fewer species per unit area; and subterranean dispersal has taken place over considerable distances. 3. High dispersal potential leads to rich species diversity and frequent sympatry. The more complex cave communities of the Mississippian plateaus permit an increase in modal size of beetles (and perhaps other troglobites) and result in greater population density and stability. 4. Ancestors of troglobites probably entered caves first as troglophiles (facultative cavernicoles), with gene flow initially continuous between epigean and hypogean populations. Extinction of epigean populations by (chiefly Pleistocene) climatic events effected geographic and genetic isolation in the caves. 5. The mechanism of eye and pigment reduction probably involves the initial reduction in genetic variability and reconstruction of the epigenotype which accompanies the speciation process. Selection for the relatively few viable gene complexes, balanced polymorphisms, and canalization systems which are possible with the limited variability available may lead indirectly toregression of adapt
Original Version:
The American Naturalist, Vol. 101, no. 922 (1967).

Record Information

Source Institution:
University of South Florida Library
Holding Location:
University of South Florida
Rights Management:
This object is protected by copyright, and is made available here for research and educational purposes. Permission to reuse, publish, or reproduce the object beyond the bounds of Fair Use or other exemptions to copyright law must be obtained from the copyright holder.

USFLDC Membership

University of South Florida
Karst Information Portal

Postcard Information



Download Options


No images or PDF downloads are available for this resource.

Cite this item close


Cras ut cursus ante, a fringilla nunc. Mauris lorem nunc, cursus sit amet enim ac, vehicula vestibulum mi. Mauris viverra nisl vel enim faucibus porta. Praesent sit amet ornare diam, non finibus nulla.


Cras efficitur magna et sapien varius, luctus ullamcorper dolor convallis. Orci varius natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Fusce sit amet justo ut erat laoreet congue sed a ante.


Phasellus ornare in augue eu imperdiet. Donec malesuada sapien ante, at vehicula orci tempor molestie. Proin vitae urna elit. Pellentesque vitae nisi et diam euismod malesuada aliquet non erat.


Nunc fringilla dolor ut dictum placerat. Proin ac neque rutrum, consectetur ligula id, laoreet ligula. Nulla lorem massa, consectetur vitae consequat in, lobortis at dolor. Nunc sed leo odio.