Quantitative acoustic differentiation of cryptic species illustrated with King and Clapper rails

Reliable species identification is vital for survey and monitoring programs. Recently, the development of digital technology for recording and analyzing vocalizations has assisted in acoustic surveying for cryptic, rare, or elusive species. However, the quantitative tools that exist for species differentiation are still being refined. Using vocalizations recorded in the course of ecological studies of a King Rail (Rallus elegans) and a Clapper Rail (Rallus crepitans) population, we assessed the accuracy and effectiveness of three parametric (logistic regression, discriminant function analysis, quadratic discriminant function analysis) and six nonparametric (support vector machine, CART, Random Forest, k�nearest neighbor, weighted k�nearest neighbor, and neural networks) statistical classification methods for differentiating these species by their kek mating call. We identified 480 kek notes of each species and quantitatively characterized them with five standardized acoustic parameters. Overall, nonparametric classification methods outperformed parametric classification methods for species differentiation (nonparametric tools were between 57% and 81% accurate, parametric tools were between 57% and 60% accurate). Of the nine classification methods, Random Forest was the most accurate and precise, resulting in 81.1% correct classification of kek notes to species. This suggests that the mating calls of these sister species are likely difficult for human observers to tell apart. However, it also implies that appropriate statistical tools may allow reasonable species�level classification accuracy of recorded calls and provide an alternative to species classification where other capture� or genotype�based survey techniques are not possible

Maternal Serologic Screening to Prevent Congenital Toxoplasmosis: A Decision-Analytic Economic Model

We constructed a decision-analytic and cost-minimization model to compare monthly maternal serological screening for congenital toxoplasmosis, prenatal treatment, and post-natal follow-up and treatment according to the current French protocol, versus no systematic screening or perinatal treatment. Costs are based on published estimates of lifetime societal costs of developmental disabilities and current diagnostic and treatment costs. Probabilities are based on published results and clinical practice in the United States and France. We use sensitivity analysis to evaluate robustness of results. We find that universal monthly maternal screening for congenital toxoplasmosis with follow-up and treatment, following the French (Paris) protocol, leads to savings of $620 per child screened. Results are robust to changes in test costs, value of statistical life, seroprevalence in women of childbearing age, fetal loss due to amniocentesis, incidence of primary T. gondii infection during pregnancy, and to bivariate analysis of test costs and incidence of primary T. gondii infection. Given the parameters in this model and a maternal screening test cost of$12, screening is cost-saving for rates of congenital infection above 1 per 10,000 live births. Universal screening according to the French protocol is cost saving for the US population within broad parameters for costs and probabilities

Persistence of Idaho fescue on degraded sagebrush-steppe

Idaho fescue (Festuca idahoensis Elmer), a palatable native perennial bunchgrass, has persisted on degraded sagebrush-steppe despite invasion by alien plants, excessive livestock grazing, and increased density of woody vegetation due to fire suppression. Survival of these populations in the presence of competitive alien plants suggested 2 possibilities: 1) that Idaho fescue produces seedlings that successfully compete for soil resources with alien invaders, and 2) that Idaho fescue seedlings tolerate stress caused by resource uptake by alien neighbors. We compared germination and growth of Idaho fescue from an undisturbed population with that of conspecific populations from disturbed (grazed and invaded) sites to determine whether disturbed-site seedlings had greater potential for resource capture. Recruitment in Idaho fescue from degraded sites did not appear to be aided by rapid seed germination or greater tolerance of moisture stress during germination. A greater proportion of seeds from the undisturbed site germinated; they germinated faster, and were no more sensitive to water stress, than were seeds from disturbed sites. For both groups, decreasing water potential from 0 to -0.5 MPa had little effect on germination percentages but declined at -1 Mpa. Germination rates slowed with decreasing water potential. Though Idaho fescue from undisturbed and disturbed sites extended roots down the soil profile with equal speed, seedlings from the undisturbed site produced 3.5 times more root length, had 2.7 times greater root length density, and 3.4 times more leaf area than disturbed-site Idaho fescue. The higher growth rate and greater root length density in Idaho fescue from the undisturbed site translates to greater exploration and exploitation of the environment. The 2 Idaho fescue groups had equivalent specific root length, specific leaf area, and root weight ratio. Idaho fescue from disturbed sites showed strong, positive geotropic growth whereas branching and diageotropic growth were greater in Idaho fescue from the undisturbed site. Cheatgrass (Bromus tectorum L.) extended roots faster than did Idaho fescue, with 17 times the root length, 6 times the root length density, and 10.8 times the leaf area of undisturbed-site Idaho fescue. Cheatgrass and Idaho fescue had equivalent specific leaf area, but specific root length of Idaho fescue was nearly twice that of the alien. Roots accounted for about 31% and 55% of cheatgrass biomass. Competitive ability did not appear to promote recruitment in Idaho fescue populations on degraded rangelands. Idaho fescue seedlings from the undisturbed-site were better competitors than disturbed-site seedlings, but interference from neighboring cheatgrass most strongly inhibited shoot growth of both Idaho fescue and cheatgrass. Idaho fescue had little effect on cheatgrass shoot growth. Selection of stress-tolerant genotypes from original populations may best explain the continued existence of Idaho fescue on grazed and invaded sites. We suggest that tolerance of moisture stress combined with vegetative longevity, are mechanisms behind Idaho fescue's persistence.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202