The Effects of Drought on Foraging Habitat Selection of Breeding Wood Storks in Coastal Georgia

Foraging habitat use by Wood Storks (Mycteria americana) during the breeding season was studied for three coastal colonies during a drought year and compared to habitat use during normal rainfall years. Information on the distribution of wetland habitat types was derived using U.S. Fish and Wildlife Service National Wetland In- ventory (NWI) data within a Geographic Information System (GIS). Foraging locations were obtained by following storks from their colonies in a fixed-winged aircraft. Differences in hydrologic condition and, the resulting prey availability in coastal zone freshwater wetlands greatly affected foraging habitat use and breeding success of the three stork colonies. In 1997 (dry), although the foraging range of each colony did not differ from wetter years, storks used estuarine foraging habitats much more extensively. Breeding success (fledged young/nest) in 1997 was less than half the success of the wetter years. Palustrine (freshwater) wetlands seem very important to storks breed- ing along the Georgia coast. During dry years, estuarine wetlands, by themselves, do not appear to be able to support the breeding population of storks in this region. Reasons why these productive wetlands do not provide sufficient resources for successful breeding are unclear, but could include limitations to only two foraging periods (low tides) in a 24-hr period

The Effects of Drought on Foraging Habitat Selection of Breeding Wood Storks in Coastal Georgia

Foraging habitat use by Wood Storks (Mycteria americana) during the breeding season was studied for three coastal colonies during a drought year and compared to habitat use during normal rainfall years. Information on the distribution of wetland habitat types was derived using U.S. Fish and Wildlife Service National Wetland In- ventory (NWI) data within a Geographic Information System (GIS). Foraging locations were obtained by following storks from their colonies in a fixed-winged aircraft. Differences in hydrologic condition and, the resulting prey availability in coastal zone freshwater wetlands greatly affected foraging habitat use and breeding success of the three stork colonies. In 1997 (dry), although the foraging range of each colony did not differ from wetter years, storks used estuarine foraging habitats much more extensively. Breeding success (fledged young/nest) in 1997 was less than half the success of the wetter years. Palustrine (freshwater) wetlands seem very important to storks breed- ing along the Georgia coast. During dry years, estuarine wetlands, by themselves, do not appear to be able to support the breeding population of storks in this region. Reasons why these productive wetlands do not provide sufficient resources for successful breeding are unclear, but could include limitations to only two foraging periods (low tides) in a 24-hr period

Identifying Sources of Error in Surveys of Devils Hole Pupfish (Cyprinodon diabolis)

We assessed four potential sources of error in estimating size of the population of Devils Hole pupfish (Cyprinodon diabolis): net, time of day, diver, and order of diver. Experimental dives (3/day) were conducted during 4 days in July 2009. Effects of the four sources of error on estimates from dive surveys were analyzed using a split-split plot ANOVA. Diver and order of diver had no significant influence on estimates, whereas the effect of presence or absence of a net was significant. Effects of time of day and presence or absence of a net showed a significant interaction with depth of water. Results indicated that pupfish may move upward during the dive, and as a result, the standard methods of dive surveys may underestimate abundance

Road-building materials in Texas

UT Librarie

Evaluation of cytotoxic, genotoxic and inflammatory responses of nanoparticles from photocopiers in three human cell lines

Background: Photocopiers emit nanoparticles with complex chemical composition. Short-term exposures to modest nanoparticle concentrations triggered upper airway inflammation and oxidative stress in healthy human volunteers in a recent study. To further understand the toxicological properties of copier-emitted nanoparticles, we studied in-vitro their ability to induce cytotoxicity, pro-inflammatory cytokine release, DNA damage, and apoptosis in relevant human cell lines. Methods: Three cell types were used: THP-1, primary human nasal- and small airway epithelial cells. Following collection in a large volume photocopy center, nanoparticles were extracted, dispersed and characterized in the cell culture medium. Cells were doped at 30, 100 and 300 μg/mL administered doses for up to 24 hrs. Estimated dose delivered to cells, was ~10% and 22% of the administered dose at 6 and 24 hrs, respectively. Gene expression analysis of key biomarkers was performed using real time quantitative PCR (RT-qPCR) in THP-1 cells at 5 μg nanoparticles/mL for 6-hr exposure for confirmation purposes. Results: Multiple cytokines, GM-CSF, IL-1β, IL-6, IL-8, IFNγ, MCP-1, TNF-α and VEGF, were significantly elevated in THP-1 cells in a dose-dependent manner. Gene expression analysis confirmed up-regulation of the TNF-α gene in THP-1 cells, consistent with cytokine findings. In both primary epithelial cells, cytokines IL-8, VEGF, EGF, IL-1α, TNF-α, IL-6 and GM-CSF were significantly elevated. Apoptosis was induced in all cell lines in a dose-dependent manner, consistent with the significant up-regulation of key apoptosis-regulating genes P53 and Casp8 in THP-1 cells. No significant DNA damage was found at any concentration with the comet assay. Up-regulation of key DNA damage and repair genes, Ku70 and Rad51, were also observed in THP-1 cells, albeit not statistically significant. Significant up-regulation of the key gene HO1 for oxidative stress, implicates oxidative stress induced by nanoparticles. Conclusions: Copier-emitted nanoparticles induced the release of pro-inflammatory cytokines, apoptosis and modest cytotoxicity but no DNA damage in all three-human cell lines. Taken together with gene expression data in THP-1 cells, we conclude that these nanoparticles are directly responsible for inflammation observed in human volunteers. Further toxicological evaluations of these nanoparticles, including across different toner formulations, are warranted

Metabolism of 2,4-dichlorophenoxyacetic acid contributes to resistance in a common waterhemp (\u3ci\u3eAmaranthus tuberculatus\u3c/i\u3e) population

BACKGROUND: Synthetic auxins such as 2,4-D have been widely used for selective control of broadleaf weeds since the mid-1940s. In 2009, an Amaranthus tuberculatus (common waterhemp) population with 10-fold resistance to 2,4-D was found in Nebraska, USA. The 2,4-D resistance mechanism was examined by conducting [14C] 2,4-D absorption, translocation and metabolism experiments. RESULTS: No differences were found in 2,4-D absorption or translocation between the resistant and susceptible A. tuberculatus. Resistant plants metabolized [14C] 2,4-D more rapidly than did susceptible plants. The half-life of [14C] 2,4-D in susceptible plants was 105 h, compared to 22 h in resistant plants. Pre-treatment with the cytochrome P450 inhibitor malathion inhibited [14C] 2,4-D metabolism in resistant plants and reduced the 2,4-D dose required for 50% growth inhibition (GR50) of resistant plants by 7-fold to 27 g ha-1, similar to the GR50 for susceptible plants in the absence of malathion. CONCLUSIONS: Our results demonstrate that rapid 2,4-D metabolism is a contributing factor to resistance in A. tuberculatus, potentially mediated by cytochrome P450. Metabolism-based resistance to 2,4-D could pose a serious challenge for A. tuberculatus control due to the potential for cross-resistance to other herbicides

Rapid volcanic ash entombment reveals the 3D anatomy of Cambrian trilobites

Knowledge of Cambrian animal anatomy is limited by preservational processes that result in compaction, size bias, and incompleteness. We document pristine three-dimensional anatomy of trilobites fossilized via rapid ash burial from a pyroclastic flow entering a shallow marine environment. Cambrian ellipsocephaloid trilobites from Morocco are articulated and undistorted, revealing exquisite details of the appendages and digestive system. Previously unknown anatomy includes a soft-tissue labrum attached to the hypostome, a slit-like mouth, and unique cephalic feeding appendages. Our findings resolve controversy over whether the trilobite hypostome is the labrum or incorporates it and establish crown-group euarthropod homologies in trilobites. This occurrence of moldic fossils with three-dimensional soft parts highlights volcanic ash deposits in marine settings as an underexplored source for exceptionally preserved organisms

Perennial grasslands enhance biodiversity and multiple ecosystem services in bioenergy landscapes

Agriculture is being challenged to provide food, and increasingly fuel, for an expanding global population. Producing bioenergy crops on marginal lands—farmland suboptimal for food crops—could help meet energy goals while minimizing competition with food production. However, the ecological costs and benefits of growing bioenergy feedstocks—primarily annual grain crops—on marginal lands have been questioned. Here we show that perennial bioenergy crops provide an alternative to annual grains that increases biodiversity of multiple taxa and sustain a variety of ecosystem functions, promoting the creation of multifunctional agricultural landscapes. We found that switchgrass and prairie plantings harbored significantly greater plant, methanotrophic bacteria, arthropod, and bird diversity than maize. Although biomass production was greater in maize, all other ecosystem services, including methane consumption, pest suppression, pollination, and conservation of grassland birds, were higher in perennial grasslands. Moreover, we found that the linkage between biodiversity and ecosystem services is dependent not only on the choice of bioenergy crop but also on its location relative to other habitats, with local landscape context as important as crop choice in determining provision of some services. Our study suggests that bioenergy policy that supports coordinated land use can diversify agricultural landscapes and sustain multiple critical ecosystem services

Foraging habitat use by wood storks nesting in the coastal zone of Georgia, USA

We studied foraging habitat use of Wood Storks (Mycteria americana) from three coastal colonies us- ing United States Fish and Wildlife Service National Wetlands Inventory data within a geographic information sys- tem (GIS). Observers followed storks from breeding colonies to foraging sites in a fixed-winged aircraft. The main objectives of the study were to estimate the foraging range of each Wood Stork colony, determine what wetland types were used in relation to their availability and spatial distribution, and determine how foraging habitat use was relat- ed to tidal stage. Storks foraged in tidal creeks during lower tide levels when prey were concentrated in shallower water, and foraged more in palustrine (freshwater) wetlands when tide levels were high. Predictability of foraging habitat use based on habitat distribution varied among colonies and depended on how wetland types were aggre- gated. Foraging locations were spatially clustered, in some cases by habitat type (estuarine vs. palustrine). These spa- tial clusterings may be explained by the proximity of a foraging location to the colony and by the habitat types around the colony. Storks also flew longer distances to forage in palustrine sites than in estuarine sites