During a two year population ecology study in a cave environment, 15 Eurycea (ZTyphlotriton) spelaea were observed ingesting bat guano. Furthermore, E. spelaea capture numbers increased significantly during the time that grey bats (Myotis grisescens) deposited fresh guano. We investigated the hypothesis that this behaviour was not incidental to the capture of invertebrate prey, but a diet switch to an energy-rich detritus in an oligotrophic environment. Stable isotope assays determined that guano may be assimilated into salamander muscle tissue, and nutritional analyses revealed that guano is a comparable food source to potential invertebrate prey items. This is the first report of coprophagy in a salamander and in any amphibian for reasons other than intestinal inoculation. Because many temperate subterranean environments are often energy poor and this limitation is thought to select for increased diet breadth, we predict that coprophagy may be common in subterranean vertebrates where it is not currently recognized.
Subterranean ecosystems harbor globally rare fauna and important water resources, but ecological processes are poorly understood and are threatened by anthropogenic stresses. Ecosystem analyses were conducted from 1997 to 2000 in Cave Springs Cave, Arkansas, situated in a region of intensive land use, to determine the degree of habitat degradation and viability of endangered fauna. Organic matter budgeting quantified energy flux and documented the dominant input as dissolved organic matter and not gray bat guano (Myotis grisescens). Carbon/nitrogen stable isotope analyses described a trophic web of Ozark cavefish (Amblyopsis rosae) that primarily consumed cave isopods (Caecidotea stiladactyla), which in turn appeared to consume benthic matter originating from a complex mixture of soil, leaf litter, and anthropogenic wastes. Septic leachate, sewage sludge, and cow manure were suspected to augment the food web and were implicated in environmental degradation. Water, sediment, and animal tissue analyses detected excess nutrients, fecal bacteria, and toxic concentrations of metals. Community assemblage may have been altered: sensitive species‐grotto salamanders (Typhlotriton spelaeus) and stygobro‐mid amphipods—were not detected, while more resilient isopods flourished. Reduction of septic and agricultural waste inputs may be necessary to restore ecosystem dynamics in this cave ecosystem to its former undisturbed condition.
We provide an updated checklist and comprehensive distributional record of Grylloblatta (Grylloblattodea: Grylloblattidae) in North America. These distribution records are based upon a thorough review of the literature, as well as unpublished data of the authors and colleagues. Thirteen species of Grylloblatta are currently described, with up to 16 additional taxa awaiting formal description. Distributional data shows that endemism of Grylloblatta is high and geographic range size is typically small: the median geographical area of 13 species and six putative species is 179 km 2 . It is clear that there is a general lack of knowledge of species range limits and local population sizes; for example, three Grylloblatta species are known from just a single locality and less than 15 specimens each. Conservation status ranks are suggested in order to update the IUCN Red List and national Natural Heritage Network Database. Finally, we describe the natural history and seasonality of Grylloblatta, discuss their unique biogeography, and provide recommendations for future surveys of grylloblattid species by highlighting known distributional gaps.
Here we review the thirty year recovery effort and conservation status of the Ozark cavefish, Amblyopsis rosae. We summarized the historic and current range of the species, and report county range extensions for both A. rosae and its confamilial Typhlichthys subterraneus. Ozark cavefish survey data spanning almost a century were analyzed for temporal trends using the Mann-Kendall Test/Sen's Slope Estimator Method. Results were inconclusive because variance was high and the majority of data sets were not sufficiently large to detect a trend. However, the two largest populations (Cave Springs Cave and Logan Cave, Benton Co., Arkansas) have stabilizing or increasing survey counts. While the number of active cavefish sites has decreased over 50% since 1990, the number of surveyed individuals has not. Reasons for endangerment were reanalyzed since federal listing; the primary threat has shifted from overcollection to habitat degradation. We analyzed the progress of recovery task implementation, and we critically evaluated the basis of delisting criteria. Recovery Task 1, the hydrogeologic delineation of subterranean habitats, is almost complete. Recovery Task 2 prescribes protection and management for Recovery Caves, and important progress has been made. Recovery Task 3 involves the development and implementation of monitoring programs in Recovery Caves. Several important studies have been performed, and indicate that many cavefish populations are experiencing chronic, low-level exposure to a suite of anthropogenic contaminants. Delisting conditions are largely unattainable as currently worded. We suggest that recovery criteria be amended such that habitat protection goals are attainable, that the list of Recovery Caves can be periodically updated, and that the recovery Environ Biol Fish (2010) 87:55-88 population goal is increased and distributed between more sites.
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