Effects of climate and exurban development on nest predation and predator presence in the southern Appalachian Mountains (USA)

In the eastern United States, land-use and climate change have likely contributed to declines in the abundance of Neotropical migrant birds that occupy forest interiors, but the mechanisms are not well understood. We conducted a nest-predation experiment in southern Appalachian Mountain forests (North Carolina, U.S.A.) during the 2009 and 2010 breeding seasons to determine the effects of exurban development and temperature on predator presence and the average number of days until eggs in an artificial nest were disturbed by predators. We baited artificial nests with quail (Excalfactoria chinensi) eggs and monitored them for 18 days. We used clay eggs, track plates, and motion-triggered cameras to detect and identify nest predators. The average number of days a nest was undisturbed decreased as mean temperature increased and, to a lesser extent, as the density of buildings increased. Nests on the ground were more often depredated than those in trees, likely due to increased predation by opossum (Didelphis virginiana) and other carnivores. Raccoons (Procyon lotor), opossums, corvids (Corvus brachyrhynchos and Cyanocitta cristata), chipmunks (Tamias striatus), black bears (Ursus americanus), and domestic cats (Felis catus) were the most commonly detected predators. Presence of these predators did not vary as a function of mean temperature. Domestic cats and corvids were detected more frequently in plots with high rather than low densities of buildings. Forest-interior specialists and Neotropical migrants often nest in cool, high-elevation areas with low housing density. These bird species, especially those that nest on the ground, may be most vulnerable to increased nest predation if temperature and exurban development increase at higher elevations as anticipated.     

CHEMICAL CONSTITUENTS IN STORM FLOW VS. DRY WEATHER DISCHARGES IN CALIFORNIA STORM WATER CONVEYANCES1

ABSTRACT: This research evaluated concentration data for selected water quality parameters in selected California urban separate storm sewer systems during storm event discharges and during dry weather conditions. We used existing monitoring data from multiple regulatory agencies and municipalities originally collected for compliance or local characterization, which allowed systematic assessment of seasonal patterns over a wide region. Long term mean concentration for most parameters in most streams was higher during storm discharges than during dry weather flows to at least 95 percent confidence in 20 of 45 comparative evaluations, and lower statistical confidence in 22 other comparisons. Some regional differences emerged: in four evaluated streams in the San Francisco Bay Area, total concentration of lead, copper and zinc were lower during dry weather than during storm flows to at least 99.9 percent confidence, with only one exception; while the other four evaluated California streams showed the same tendency, but to much lower statistical confidence.     

Statistical methods for forecasting daily snow depths and assessing trends in inter-annual snow depth dynamics

Environmental and Ecological Statistics - This paper introduces a time-varying parameter regression model for modeling, forecasting, and assessing inter-annual trends in daily snow depths. The...     

One century sedimentary records of polycyclic aromatic hydrocarbons, mercury and trace elements in the Qinghai Lake, Tibetan Plateau

Sediments from a remote lake of northeastern Tibetan Plateau were analyzed for polycyclic aromatic hydrocarbons (PAHs) and trace metals. USEPA priority PAHs, ranged from 11 in 1860 to 279 ng g⁻¹ in 2002, while, the deposition fluxes were in the range of 0.2-11.4 ng cm⁻² yr⁻¹. Similarly, from 1860 to 2002, an increased trend of Hg flux was observed (0.5-3.2 ng cm⁻² yr⁻¹). Remarkable increase of PAHs and Hg concentration began from 1970, nearly the same period of the “Reform and Open” Policy had been embarked (1978) in China. Good correlations were found between concentrations of Pb, Zn, Cd, As, Hg, and PAHs, which suggested the sources of these chemicals in the sediment is analogous, likely from anthroprogenic sources. Based on isomer ratios, PAHs in core were dominantly from the incomplete combustion of coal. Owing to the proximity to dust source area (Qaidam Basin) and the close association between PAHs, Hg, Pb, and particle matters, atmospheric dust-transport and deposition might be the main pathways that pollutants enter into Qinghai Lake.     

A Sampler for Measuring Deposited Fine Sediments in Streams1

Turner, Andy W., Jeff J. Hillis, and Charles F. Rabeni, 2012. A Sampler for Measuring Deposited Fine Sediments in Streams. Journal of the American Water Resources Association (JAWRA) 48(2): 366‐378. DOI: 10.1111/j.1752‐1688.2011.00618.x Abstract: Improvements and standardization of methodologies to quickly and accurately quantify deposited sediment in streams will allow advances in our understanding of biological effects of sedimentation. Most methods used to evaluate streambed conditions as part of biological monitoring or assessment programs are selected for ease of use, but can be subjective, inappropriate, and often of unknown accuracy. We developed a portable, light‐weight device to quantify deposited unconsolidated sediment (particles <2 mm) in wadeable streams. This deposited sediment sampler is a hand‐held unit that circumscribes an area of the streambed and through suction creates a force that suspends unconsolidated materials into a collector. Laboratory evaluations determined the efficiency (percent of available deposited sediment recovered) of the sampler to collect different sizes and concentrations of deposited sediment under differing streambed conditions, which allowed appropriate correction factors to be applied to each of four categories of streambed particle size. Field trials comparing our sampler to other methods commonly used by many state and federal agencies showed high comparability. The sampler can be constructed in just a few hours from inexpensive, easily obtained materials.     

Leaching of Cu and Zn from discarded boat paint particles into tap water and rain water

We studied the leaching of copper and zinc from particles of discarded boat paint added to tap water (pH 7.3) and rain water (pH = 4.7), simulating conditions encountered during the hosing or runoff of antifouling waste. Leaching rates appeared to be diffusion-controlled and were greater in rain water than in tap water and were greater for Zn than for Cu. After a period of 120 h, between about 0.5% and 3% of total Cu and 5-30% of total Zn had been released to the aqueous phase. These observations suggest that Cu and Zn mobilised from fine antifouling particulates during washdown or rainfall events may be important contaminants of runoff and soils in the vicinity of boat repair facilities.     

Leaching of zinc from tire wear particles under simulated estuarine conditions

Tire wear particles (TWP) abraded from end-of-life passenger car tires have been added at a concentration of 1 g L⁻¹ to river water, sea water and mixtures thereof in order to examine the chemical controls on the leaching of Zn from the rubber matrix. Results of time-dependent experiments conducted over a period of 5 days were consistent with a diffusion controlled leaching mechanism with rate constants of about 0.04 mg L⁻¹ h^−1/2 in river water and between about 0.02 and 0.03 mg L⁻¹ h^−1/2 in sea water. Additional experiments revealed a reduction in Zn dissolution with both increasing salinity and pH and enhancement of leaching in the presence of fluorescent light compared with dark conditions. In corresponding experiments conducted in the presence of a fixed quantity (0.8 g L⁻¹) of clean, fractionated estuarine sediment, aqueous Zn concentrations were reduced by at least an order of magnitude. Increasing the quantity of sediment resulted in a progressive reduction in Zn concentration until an apparent equilibrium was achieved, with partition coefficients defining the sediment-water distribution of Zn of about 550 mL g⁻¹ and 270 mL g⁻¹ in river water and sea water, respectively. Results are interpreted in terms of the dissolution of ZnO and other residual complexes from the matrix and the subsequent, rapid adsorption of Zn²⁺ ions to coexistent estuarine sediment. The findings of the study are discussed in terms of their implications for the transport, fate and effects of TWP Zn in aquatic environments that are likely to receive urban runoff.     

Extending Fabric Filter Capabilities

It has been amply demonstrated that there are reasons for improving the collection of fine participates. Some areas of research and development which may prove fruitful in extending fabric filter capabilities have been suggested.     

Sizing and Costing of fabric Filters Part II: Costing Considerations

This is the second of a two-part article that reviews baghouse filtration theory, presents size estimating methods, and gives costing procedures for a variety of baghouse types and sizes. Part I of the article discussed theory and sizing; this part presents costing. Information is given for estimating total capital investment including separate costs for the bare baghouse (five types), bags, and, where needed, cages and Venturis. Factors are given for installation and for indirect costs. Direct and indirect annual costs are discussed. An example problem is given. The material in this article is taken primarily from the EAB Control Cost Manual.