My coauthor Steve Taylor and my paper on the conservation status and biogeography of subterranean Bactrurus amphipods was recently published in the journal Subterranean Biology. The full citation and abstract are below.
Taylor SJ, & Niemiller ML. 2016. Biogeography and conservation assessment of Bactrurus groundwater amphipods (Crangonyctidae) in the central and eastern United States. Subterranean Biology 17: 1–29.
The subterranean amphipod genus Bactrurus (Amphipoda: Crangonyctidae) is comprised of eight species that occur in groundwater habitats in karst and glacial deposits of the central and eastern United States. We reexamine the distribution, biogeography, and conservation status of Bactrurus in light of new species distribution records and divergence time estimates in the genus from a recent molecular study. In particular, we discuss hypotheses regarding the distribution and dispersal of B. mucronatus and B. brachycaudus into previously glaciated regions of the Central Lowlands. We also conducted the first IUCN Red List conservation assessments and reassessed global NatureServe conservation ranks for each species. We identified 17 threats associated with increased extinction risk that vary in source, scope, and severity among species, with groundwater pollution being the most significant threat to all species. Our conservation assessments indicate that five of the eight species are at an elevated risk of extinction under IUCN Red List or NatureServe criteria, with one species (B. cellulanus) already extinct. However, none of the eight species are considered threatened or endangered by any state or federal agency. Significant knowledge gaps regarding the life history, ecology, and demography of each species exist. Given results of our conservation assessments and available information on threats to populations, we offer recommendations for conservation, management, and future research for each species.
A paper comparing the life history and ecology of cave and surface populations of the Western Slimy Salamander (Plethodon albagula) in Texas was recently published in the journal Herpetological Conservation and Biology. The full citation and abstract are below.
Taylor SJ, Krejca JK, Niemiller ML, Dreslik MJ, & Phillips CA. Life history and demographic differences between cave and surface populations of the western slimy salamander, Plethodon albagula (Caudata: Plethodontidae), in central Texas. Herpetological Conservation and Biology 10: 740–752.
The Western Slimy Salamander (Plethodon albagula) in central Texas is known from both surface and cave environments. Threshold species, such as P. albagula, may be excellent candidates to study potential differences in life history traits during the evolutionary transition from surface into subterranean habitats. We conducted a 29-mo mark-recapture study of a surface and a cave population in Bell County, Texas, USA, to determine whether these populations differed in body size, growth rate, age at sexual maturity, and life span. We employed a growth model to estimate growth rate, age at sexual maturity, and life span, and an open population model to estimate population size, density, catchability, and survival rates. Salamanders were smaller on average and reached a smaller maximum size in the surface population compared to the cave population, which was skewed toward larger, older individuals. Growth trajectories were similar between populations, but the cave population reached sexual maturity faster (0.9–1.4 y) than the surface population (1.5–2.2 y). Survival rates were similar between populations. Although population size estimates were 10 times higher for the surface compared to the cave population, densities were similar between sites suggesting that habitat availability alone could explain population size differences. Plethodon albagula exhibits plasticity in growth, body size, and development, which may be adaptive and a function of extreme variation in surface environmental conditions. Subterranean habitats may be important for the long-term persistence of local populations, which may persist for years in subterranean habitats.