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Marsh loss is a problem in many areas around the world. In order to combat the problem, scientists and managers need tools to determine its cause and evaluate the effectiveness of management techniques. Current methods for estimating productivity and identifying factors that limit productivity are too time-consuming or expensive for wide-spread, regular use, however. In coastal Louisiana, where Spartina patens (Ait.) Muhl is the most common plant, restoration seeks to slow wetland loss rates that averaged approximately 77.4 km²/year between 1978 and 2000. We used the chemical composition of leaf tissue from S. patens grown under controlled conditions to create a simple and inexpensive tool to identify salinity stress and nutrient limitation. By growing S. patens at varying nitrogen availability and salinity levels, we found that C:N ratios and Na concentrations can be used to classify factors that limit production in S. patens.

Hydrocarbons increase abundance of hydrocarbon- degrading microorganisms, but also decrease microbial diversity. This could disrupt ecosystem dynamics by altering soil organic matter mineralization and resultant nutrient remineralization rates. Crude oil, which is known to contain toxins and reduce microbial diversity, was hypothesized to reduce gross metabolic activity of mixed microbial populations in wetland soils. Soil respiration and Eh were compared, for 6 months, among microcosms containing marsh soils that differed in soil organic matter (Panicum hemitomon Shult. or Sagittaria lancifolia L. dominated marshes), crude oil (Arabian crude, Louisiana crude, or no oil), and additives (a cleaner, a dispersant, fertilizer, or no additive). No treatment slowed activity; instead, Louisiana plus fertilizer and all Arabian treatments temporarily accelerated activity. Additional C respired from oiled microcosms exceeded C added as crude oil by 1.4 to 3.5 times. Thus, much additional C originated from soil organic matter rather than crude oil. Crude oils temporarily lowered soil Eh, which is consistent with accelerated metabolism and demand for electron acceptors. The lack of inhibition observed at the community level does not necessarily indicate an absence of toxicity. Instead, tolerant species with metabolic versatility probably maintained activity. Stimulation probably resulted from removal of micronutrient limitation, rather than removal of grazing pressure or macronutrient limitation. Regardless, accelerated soil organic matter mineralization surely accelerated nutrient remineralization. This might explain some reports of crude oil stimulating plant growth. These results are not inconsistent with theoretical and experimental conclusions regarding effects of biodiversity on ecosystem stability and productivity, nor are they inconsistent with conclusions that crude oils contain components that are toxic to microbes, vegetation, and fauna. However, these data do indicate that crude oils also contain components that temporarily stimulate metabolic activity of surviving microbes.

Tobias, V.D. and Nyman, J.A., 2017. Leaf tissue indicators of flooding stress in the above- and belowground biomass of Spartina patens. Many factors, such as rising sea levels and human alterations, threaten coastal wetlands in the United States and around the world. To reverse some wetland loss, dredge material, tidal flow, or river flow can be used to create new wetlands, or existing wetlands can be managed to increase plant productivity. Identifying the causes of limited production can improve management plans by suggesting possible remedies. Managing and restoring marshes depends on understanding which stress factors limit growth of key marsh-building plants. Spartina patens is a common marsh-building species of grass in brackish marshes along the Gulf of Mexico and Atlantic coasts of North America, and it is often the target of management and restoration plans. Spartina patens was grown under six flooding levels in a field experiment. Spartina patens plants grown at lower elevations had consistently lower biomass, in contrast to Spartina alterniflora, which has been shown to exhibit peak biomass at intermediate levels of flooding. Critical values of elemental concentrations in plant tissue are widely used to diagnose mineral deficiencies in agricultural crops and are just beginning to be developed to aid wetland management and restoration. For leaf tissue harvested in summer, [Mn] < 256 ppm and [Ca] < 0.3% indicated that plants grew at lower elevations and had limited biomass. The results suggest that concentrations of Mn and Ca in the leaf tissue of S. patens could form part of an indicator to monitor belowground productivity of marshes. Although low concentrations of these elements were associated with the smaller root and shoot biomass of plants grown at low elevations, variability in the relationship suggests that additional factors may need to be considered. Marsh managers should monitor soil elevation loss carefully if they choose to drain marshes to increase plant production to prevent excessive loss of soil elevation.

Nyman, J.A.; Baltz, D.M.; Kaller, M.D.; Leberg, P.L.; Parsons Richards, C.; Romaire, R.P., and Soniat, T.M., 2013. Likely changes in habitat quality for fish and wildlife in coastal Louisiana during the next fifty years. Louisiana's 2012 Master Plan for a sustainable coast was designed to minimize economic damage from storm surges and to maximize wetland habitat for fish and wildlife. Selecting projects for inclusion in the master plan depended partly on models that simulated the effects of management options on environmental factors that control habitat quality for fish and wildlife. We used 13 models to predict the effects of the master plan on habitat quality for fish and wildlife in coastal Louisiana. Habitat quality was predicted to change more for the Neotropical songbirds and seven other modeled species losing habitat quality with the status quo (−37%) than it was predicted to increase for five modeled species gaining habitat quality with the status quo (+18%). The master plan was predicted to slow or negate all changes associated with the status quo. All of the modeled fish and wildlife belong to people of the state of Louisiana, people living in countries bordering the Gulf of Mexico, and to people throughout the Americas. Thus, declining fish and wildlife habitat quality in Louisiana probably will cause market and nonmarket losses, which although concentrated in Louisiana, will extend across the Americas. As funding for Louisiana's master plan is pursued, it is important to consider that almost all of the causes for net wetland losses in Louisiana are external to the owners of these wetlands but that the fish and wildlife that use these wetlands belong to and benefit people throughout the Americas.

Much time and many resources are spent managing coastal wetlands for the roughly four million waterfowl that winter in Louisiana marshes. Waterfowl managers in coastal Louisiana often aim to increase submergent aquatic vegetation (SAV) abundance to support more waterfowl because duck populations in winter are believed to be food limited. Management of marshes with fixed-crest weirs increases SAV by minimizing fluctuations in salinity, water levels, and turbidity, but the effect of weirs varies from year to year. Joanen and Glasgow (1965) reported a winter decline in Louisiana SAV - declines that may be caused by wintering waterfowl depleting SAV through feeding, or in response to seasonal changes such as water temperature or day length. However, there are no data, other than that collected by Joanen and Glasgow (1965), relating SAV abundance on the Gulf Coast to waterfowl herbivory, and those results never have been replicated. Our objective was to document the effects of season and a new type of management on SAV abundance in order to determine what seasonal patterns exist, if any, and to determine if management was effective at increasing SAV. To determine why management was effective or ineffective, we also documented water quality parameters (salinity, temperature, water level, turbidity, and nutrients) and tested a second hypothesis in which we postulated that these parameters did not differ among the study areas or with SAV abundance.

In recent years, nursing home care expenditures have approached 1% of GNP. Their growth is a major contributor to the escalating costs of health care. In this article, we analyze a sample of nursing homes from Wisconsin to determine the characteristics of the efficiently operated nursing homes. Data envelopment analysis is used to calculate efficiency scores for the various nursing homes in the sample. We then use regression analysis to investigate the determinants of efficiency, holding constant the characteristics of the output. We find that for-profit firms have significantly higher efficiency scores.

Wildfire can affect soil hydraulic properties, often resulting in reduced infiltration. The magnitude of change in infiltration varies depending on the burn severity. Quantitative approaches to link burn severity with changes in infiltration are lacking. This study uses controlled laboratory measurements to determine relations between a remotely sensed burn severity metric (dNBR, change in normalised burn ratio) and soil hydraulic properties (SHPs). SHPs were measured on soil cores collected from an area burned by the 2013 Black Forest fire in Colorado, USA. Six sites with the same soil type were selected across a range of burn severities, and 10 random soil cores were collected from each site within a 30-m diameter circle. Cumulative infiltration measurements were made in the laboratory using a tension infiltrometer to determine field-saturated hydraulic conductivity, Kfs, and sorptivity, S. These measurements were correlated with dNBR for values ranging from 124 (low severity) to 886 (high severity). SHPs were related to dNBR by inverse functions for specific conditions of water repellency (at the time of sampling) and soil texture. Both functions had a threshold value for dNBR between 124 and 420, where Kfs and S were unchanged and equal to values for soil unaffected by fire. For dNBRs >~420, the Kfs was an exponentially decreasing function of dNBR and S was a linearly decreasing function of dNBR. These initial quantitative empirical relations provide a first step to link SHPs to burn severity, and can be used in quantitative infiltration models to predict post-wildfire infiltration and resulting runoff.

Nanofiber-reinforced hydrogels have recently gained attention in biomedical engineering. Such three-dimensional scaffolds show the mechanical strength and toughness of fibers while benefiting from the cooling and absorbing properties of hydrogels as well as a large pore size, potentially aiding cell migration. While many of such systems are prepared by complicated processes where fibers are produced separately to later be embedded in a hydrogel, we here provide proof of concept for a one-step solution. In more detail, we produced core-shell nanofibers from the natural proteins zein and gelatin by coaxial electrospinning. Upon hydration, the nanofibers were capable of directly transforming into a nanofiber-reinforced hydrogel, where the nanofibrous structure was retained by the zein core, while the gelatin-based shell turned into a hydrogel matrix. Our nanofiber-hydrogel composite showed swelling to ~800% of its original volume and water uptake of up to ~2500% in weight. The physical integrity of the nanofiber-reinforced hydrogel was found to be significantly improved in comparison to a hydrogel system without nanofibers. Additionally, tetracycline hydrochloride was incorporated into the fibers as an antimicrobial agent, and antimicrobial activity against Staphylococcus aureus and Escherichia coli was confirmed.

The sawflies that feed on the plant family Salicaceae can be divided into eight informal groups based on larval feeding habit or gall type: (1) species with free-living larvae; (2) leaf folders; (3) leaf blade gallers; (4) apical leaf gallers; (5) basal leaf gallers; (6) midrib and petiole gallers; (7) stem gallers; and (8) bud gallers. It has been proposed that the galling habit evolved from free-living larvae via leaf folders, and that the different gall types evolved gradually in the sequence mentioned above. Thus, the galling site would have 'wandered' from the leaf margin toward the stem as a result of gradual changes in oviposition site preference. Allozyme data from eight informative loci were used to reconstruct the phylogeny of 18 representative sawfly species. The results suggest that indeed leaf folders seem to be a basal group; leaf blade gallers evolved independently of the other true gallers; apical and basal leaf gallers are not the ancestors of petiole and bud gallers, but they may share a common galling ancestor; bud gallers evolved from midrib/petiole gallers; and stem gallers are polyphyletic. The cause for the observed wandering of the galling site could be intraspecific competition due to a possible 'nutrient shading effect' of galls situated closer to the host plant's main vascular system.