After a 20-year hiatus during which few archaeologists discussed fluoride dating, the method again received attention in the 1980s and 1990s when some argued for its validity. As a dating method, fluoride dating depends on the rate at which fluorine ions replace hydroxyl ions in osseous tissue. The rate of replacement is influenced by the properties of the skeletal part (SP), sediment chemistry (K), and sediment hydrology (H), and the replacement rate influences estimates of time. Calibrated AMS radiocarbon assays of 10 black bear (Ursus americanus) femora from a natural-trap cave in central Missouri are weakly correlated with fluorine concentrations, determined by neutron activation analysis in the 10 femora. Despite minimal variation in SP, K, and H, results indicate fluoride dating can be considered a valid dating method only in cases when the chronological validity of its results are confirmed with independent chronometric data. As similarities in fluorine amounts across specimens increase, provenience information and bone orientation data as well as fine resolution data on K and H become critical to the application of fluoride dating.

Human population growth and intensification of resource extraction during the 19th century changed the American landscape. Deforestation, residential sprawl and hunting activities impacted the behavior and sometimes the existence of native species. By the early 1900s, North American black bears (Ursus americanus) were extirpated from Missouri. Modern efforts to restore this species to the region are guided by the assumption that extant extra-local black bear ecology accurately depicts native Missouri ursid ecology. Paleozoological data provide the only means to test this assumption. Stable carbon and nitrogen isotope analysis of skeletal remains of ten late Holocene black bears from Lawson Cave in central Missouri reveals three aspects of native black bear diet: 1) Lawson Cave black bears are isotopically distinct from herbivores and carnivores; 2) There is no clear trend in black bear diet over the past 600 years; and 3) Lawson Cave black bear diet is not significantly different from that of modern black bears. Native Missouri black bears, as reflected by the Lawson Cave ursids, are no different from extra-local modern black bears in terms of diet. Therefore, these ecological data can be applied to future management and conservation planning regarding Missouri black bears by indicating appropriate regions (which can support the resourceuse habits of black bears) for relocation programs.