A Vegetation-Based Index of Biotic Integrity for Wetlands of Kentucky

Wetland ecosystems have experienced severe declines across the United States, prompting efforts to assess the status of remaining wetlands and regulate their development. The Clean Water Act and the policy of “No Net Loss” have resulted in a system of permitting and mitigation for impacts to wetlands. Professional judgments of wetland quality are inherent in regulatory decisions related to preservation and mitigation, but many states, and until recently including Kentucky, have no standard, quantifiable means of assessing wetlands to guide the decision process. A rapid assessment method has recently been developed for Kentucky, but there is no intensive assessment method for wetlands. Indices of biotic integrity (IBIs) are multimetric assessment methods that use characteristics of biological communities in wetlands as indicators of ecological integrity, or the degree to which a habit resembles a pristine reference condition. IBIs are increasingly being developed for specific regions and nationally as tools to aid in regulatory decisions and for ambient monitoring purposes. The goal of this study was to develop a vegetation-based IBI (VIBI) to assess the condition of wetlands in Kentucky and test it against the recently developed Kentucky Rapid Assessment Method (KY-WRAM). Using survey data from 110 primarily riverine wetlands across five river basins in Kentucky from 2011 to 2015, I calculated 125 candidate vegetation metrics and tested their correlation to a disturbance index, which was comprised of aggregated measures of anthropogenic landscape, physical, and hydrological alterations. Forested, emergent, and shrub wetlands were included in the survey sample. Ultimately, one VIBI was developed for all wetland vegetation classes and consisted of two metrics, MeanC, the average of all species CC values at a site, and Absolute Cover of Nonnatives. These metrics are broad enough to apply to a wide range of wetland vegetation classes and HGM types and reflect wetland condition via floristic quality and the degree of invasion by nonnatives. The final VIBI distinguished KY-WRAM category one wetlands from category three wetlands for both development (F2,79 = 16.54, p\u3c0.001) and validation (F2,13 = 15.59, p\u3c0.001) datasets. Further work should test the applicability of this VIBI on wetlands in the two additional basins of Kentucky and on other wetland types, in addition to accumulating a greater sample size for some types tested in this study. Because emergent wetlands tended to score lower overall than forested wetlands, separate interpretation of emergent and forested wetland scores should be considered, but I recommend doing so only after more sites are added to the dataset

Locally finite simple weight modules over twisted generalized Weyl algebras

We present methods and explicit formulas for describing simple weight modules over twisted generalized Weyl algebras. When a certain commutative subalgebra is finitely generated over an algebraically closed field we obtain a classification of a class of locally finite simple weight modules as those induced from simple modules over a subalgebra isomorphic to a tensor product of noncommutative tori. As an application we describe simple weight modules over the quantized Weyl algebra.Comment: 28 page

Late Quaternary Vegetational History at Cupola Pond, Ozark National Scenic Riverways, Southeastern Missouri

A 12 meter core of lacustrine sediments from Cupola Pond, Ripley County, Missouri, Provides the first continuous record in the Ozark Plateaus Region of ecologic changes from full-glacial time to the present. From 17,100 to 15,350 yr B.P., forest communities were dominated by jack and/or red pine (northern Diploxylon Pinus) and spruce (Picea). A late-glacial, transitional forest of oak (Quercus), ash (Fraxinus), pine and spruce characterized the upland vegetation that occurred during a period of climatic amelioration between 15,350 and 12,300 yr B.P. The early Holocene period from 12,300 to 9,100 yr B.P. was marked by the collapse of the northern Diploxylon pine, spruce, and ash populations, and the expansion of cool-temperate species of oak, hickory (Carya), and hornbeam (Carpinus/Ostrya type) as well as herbs of the family Compositae. Mid-Holocene warming between 9,100 and 6,700 yr B.P. brought about an apparent major decrease in the species richness of deciduous arboreal taxa. During a period of peak warming between 6,700 and 6,350 yr B.P., an oak park-land dominated the uplands (together, oak and grass (Gramineae) represented 92% of the upland-pollen assemblage). Buttonbush (Cephalanthus occidentalis) established around the shallow margin of Cupola Pond by 4,500 yr B.P. By 3,500 yr B. P., during the late-Holocene interval, the upland vegetation of oak parkland was replace by a forest dominated by shortleaf pine (southern Diploxylon Pinus). By 3,300 yr B.P., as temperate forested environments replaced the more xeric parkland environments in the uplands, populations of tupelogum (Nyssa aquatica) locally established in the bottomlands around Cupola Pond. The sequential migration of tree taxa during the late-glacial and throughout the Holocene reflects both a biotic response to climatic change, and differences in rate and routes of migration from full-glacial refugial areas. However, taxon calibrations and modern analogues (using dissimilarity coefficients of Euclidian Distance, Standard Euclidian Distance, and Chord Distance), indicate that the Southeastern Ozark Plateaus provided a full-glacial refuge of cool-temperate deciduous taxa, including oak, maple (Acer), ash, elm and willow (Salix)

Failure properties of loaded fiber bundles having a lower cutoff in fiber threshold distribution

Presence of lower cutoff in fiber threshold distribution may affect the failure properties of a bundle of fibers subjected to external load. We investigate this possibility both in a equal load sharing (ELS) fiber bundle model and in local load sharing (LLS) one. We show analytically that in ELS model, the critical strength gets modified due to the presence of lower cutoff and it becomes bounded by an upper limit. Although the dynamic exponents for the susceptibility and relaxation time remain unchanged, the avalanche size distribution shows a permanent deviation from the mean-fiels power law. In the LLS model, we analytically estimate the upper limit of the lower cutoff above which the bundle fails at one instant. Also the system size variation of bundle's strength and the avalanche statistics show strong dependence on the lower cutoff level.Comment: 7 pages and 7 figure

Key steps in the morphogenesis of a cranial placode in an invertebrate chordate, the tunicate Ciona savignyi

AbstractTunicates and vertebrates share a common ancestor that possessed cranial neurogenic placodes, thickenings in embryonic head epidermis giving rise to sensory structures. Though orthology assignments between vertebrate and tunicate placodes are not entirely resolved, vertebrate otic placodes and tunicate atrial siphon primordia are thought to be homologous based on morphology and position, gene expression, and a common signaling requirement during induction. Here, we probe key points in the morphogenesis of the tunicate atrial siphon. We show that the siphon primordium arises within a non-dividing field of lateral–dorsal epidermis. The initial steps of atrial primordium invagination are similar to otic placode invagination, but a placode-derived vesicle is never observed as for the otic vesicle of vertebrates. Rather, confocal imaging reveals an atrial opening through juvenile stages and beyond. We inject a photoactivatable lineage tracer to show that the early atrial siphon of the metamorphic juvenile, including its aperture and lining, derives from cells of the atrial placode itself. Finally, we perturb the routing of the gut to the left atrium by laser ablation and pharmacology to show that this adaptation to a sessile lifestyle depends on left–right patterning mechanisms present in the free-swimming chordate ancestor

The Dark Matter Distribution in Abell 383: Evidence for a Shallow Density Cusp from Improved Lensing, Stellar Kinematic and X-ray Data

We extend our analyses of the dark matter (DM) distribution in relaxed clusters to the case of Abell 383, a luminous X-ray cluster at z=0.189 with a dominant central galaxy and numerous strongly-lensed features. Following our earlier papers, we combine strong and weak lensing constraints secured with Hubble Space Telescope and Subaru imaging with the radial profile of the stellar velocity dispersion of the central galaxy, essential for separating the baryonic mass distribution in the cluster core. Hydrostatic mass estimates from Chandra X-ray observations further constrain the solution. These combined datasets provide nearly continuous constraints extending from 2 kpc to 1.5 Mpc in radius, allowing stringent tests of results from recent numerical simulations. Two key improvements in our data and its analysis make this the most robust case yet for a shallow slope \beta of the DM density profile \rho_DM ~ r^-\beta on small scales. First, following deep Keck spectroscopy, we have secured the stellar velocity dispersion profile to a radius of 26 kpc for the first time in a lensing cluster. Secondly, we improve our previous analysis by adopting a triaxial DM distribution and axisymmetric dynamical models. We demonstate that in this remarkably well-constrained system, the logarithmic slope of the DM density at small radii is \beta < 1.0 (95% confidence). An improved treatment of baryonic physics is necessary, but possibly insufficient, to reconcile our observations with the recent results of high-resolution simulations.Comment: Accepted to ApJ Letter

Detecting Low Incidents Effects: The Value of Mixed Methods Research Design in Low-N Studies

Many important educational situations such as traumatic brain injury among preschoolers, school gun violence, preadolescent eating disorders, and adolescent suicide happen relatively infrequently. In this article, the authors explain why mixed methods research designs offer more meaningful empirical results than do qualitative or quantitative designs alone when asking research questions about low incident situations. The authors present and explain three mixed methods models applicable to low incidents situations