Annette Summers Engel
Donald H. Jones Professor of Aqueous Geochemistry
University of Tennessee at Knoxville
Department of Earth and Planetary Sciences
Engel Lab Research -
Biodiversity of caves and karst in the Valley and Ridge
Of the >50,000 caves reported in the United States, over 1,138 cave-restricted animals have been described. These troglobionts (terrestrial obligate cave species) and stygobionts (aquatic obligate cave species) possess traits uniquely associated with life in perpetual darkness and limited food resources. One of the richest karst areas in the United States is in TAG (Tennessee, Alabama and Georgia), with Tennessee currently ranking 2nd to Texas for the most obligate subterranean species. Tennessee currently has more mapped caves than any other state, at over 10,000. However, recent examinations of spatial patterns of cave biodiversity, species richness, and endemism in Tennessee identify that only 5% of Valley and Ridge caves (of ~500 caves) have fauna records. Almost nothing is known about the microbiology of caves in Tennessee. Moreover, several undersampled areas exist, including in northeast Tennessee extending from the more intensely inventoried southwestern Virginia karst. As such, it is possible that many TAG cave species await discovery and description. There is still much to be learned about the distribution of obligate cave fauna, their evolutionary histories, and ecosystem dynamics (including food web structures and microbial detrital loop).
We are exploring at least 100 caves to address sampling gaps in TAG Valley and Ridge caves. Our goals are to (1) conduct biological inventories, which include ecological and life history information for species, and (2) document species occurrences that define geographic extents and examine spatial patterns of biodiversity, endemism, and sampling effort. From these data, we plan to develop an educational outreach program that will promote awareness and conservation of subterranean fauna throughout TAG. So far, we have discovered many new populations for spiders, beetles, mites, and aquatic invertebrates. 

Project website

Current Support: Cave Conservancy of the Virginias; University of Tennessee, Jones Endowment
Dr. Matthew L. Niemiller, University of Illinois at Urbana-Champaign ( website )
Dr. Kirk Zigler, The University of the South
Dr. Dante Fenolio, San Antonio Zoo
Dr. K. Denise Kendall (University of Illinois, Champaign-Urbana) 

Related Publications and Presentation from Group

Niemiller, M.L., Zigler, K.S., Hart, P.B., Kuhajda, B.R., Armbruster, J.W., Ayala, B.N., Engel, A.S. (2016) First record of a stygobiotic fish (Percopsiformes: Amblyopsidae: Typhlichthys) from the Appalachians karst region in the eastern United States. Subterranean Biology. 20: 39-50. doi:10.3897/subtbiol.20.9693

Zigler, K.S., Kuhajda, B.R., Ayala, B.N., Niemiller, M.L., Engel, A.S. (2015) First observation of Southern Cavefish (Typhlichthys subterraneus) east of the Cumberland Plateau. Bulletin of the Georgia Speleological Society 2015: 9-11.

Keenan, S.W. Paterson, A.T., Niemiller, M.L., Slay, M., Engel, A.S. (2016) The first observations of a stygobiont snail (Hydrobiddae, Fontigens sp.) in Tennessee. National Speleological Society meeting, Ely, Nevada, July, 2016.

Engel, A.S. (2016) Prevalence of microbial taxonomic groups to specific subterranean habitats may shed light on ubiquity of microbial function in cave ecosystems. International Conference for Subterranean Biology, Fayetteville, Arkansas. June 12-17, 2016. p. 20. 

Niemiller, M.L., Zigler, K.S., Stephen, C.D.R., Carter, E.T., Paterson, A.T., Taylor, S.J., Engel, A.S. (2016) Vertebrate fauna in caves of the east Tennessee Valley and Ridge region (USA). Journal of Cave and Karst Studies. 78:1-24. DOI:10.4311/2015LSC0109.
Niemiller, M.L., Zigler, K.S., Stephen, C.D.R., Carter, E.T., Paterson, A.T., Taylor, S.J., Fenolio, D.B., Kendall, K.D., Engel, A.S. (2015) Updated invertebrate and vertebrate cave fauna records for eastern Tennessee Appalachian Valley and Ridge. National Speleological Society convention, Waynesville, Missouri, July 13-17, 2015. (talk)
Kendall, K.D., Niemiller, M.L., Engel, A.S., Zigler, K.S., Fenolio, D.B. (2015) Cave biodiversity and conservation teaching and learning module for K-5 students in the Tennessee-Alabama-Georgia region. National Speleological Society convention, Waynesville, Missouri, July 13-17, 2015. (poster)

Field Photographs

Representative troglobionts observed in the Valley and Ridge caves during bioinventories in Year 1 of the project: A) a cave ant beetle (Batriasymmodes spelaeus) from Grainger Co., TN; B) a terrestrial cave isopod (Amerigoniscus nicholasi) from Roane Co., TN; C) a cave milliped (Scoterpes copei) from Meigs Co., TN; D) an undescribed aquatic cave snail (Antrorbis n. sp.) from Roane Co., TN; E) Tennessee Cave Beetle (Pseudanophthalmus tennesseensis) from Knox Co., TN; F) Appalachian Valley Cave Amphipod (Crangonyx antennatus) from Meigs Co., TN. All photographs by Dr. Matthew L. Niemiller. 
Geochemistry. Geomicrobiology. Geology. Ecology.

Interdisciplinary Research at the University of Tennessee