ESTIMATING LOW-FLOW QUANTILES FROM DRAINAGE-BASIN CHARACTERISTICS IN NEW HAMPSHIRE AND VERMONT1

ABSTRACT: This study systematically develops, validates, and compares alternative approaches for estimating quantiles of the distribution of annual minimum seven-day-average flows (7Q) for ungaged, unregulated drainage basins in New Hampshire and Vermont via regression on map-measurable drainage-basin characteristics. At 47 gaging stations in the region, the hypotheses that 7Q is log normally distributed and serially independent are not rejected, and the regional average spatial correlation is R= 0.35. Step-forward examination of a suite of potential predictor variables revealed that logarithm of drainage area, mean elevation, and fraction of basin covered with sand and gravel deposits are significant predictors of quantiles of 7Q. The regression equations were incorporated into four approaches to estimate the 7Q value with a nonexceedence probability of 0.1, 7Q10. Comparison of observed values and values predicted via a delete-one jackknife resampling validation indicates that one of the approaches gives estimates with acceptable bias and precision, with median relative error of 33 percent and prediction error of 64 percent. This is equivalent to the precision obtainable with only one to two years of gaging records. In spite of this limited precision, the approaches developed herein are useful for predicting 7Q quantiles at ungaged sites. Further improvement in precision will likely be possible only by exploiting the spatial correlation of annual 7Q.     

Magnetic particle technology in environmental remediation and wildlife rehabilitation

The use of magnetic particles in environmental remediation and wildlife rehabilitation is currently under investigation at Victoria University, in collaboration with the Phillip Island Research Centre, Victoria, Australia. Iron powder has been shown to be very effective for the magnetic cleansing of feathers and plumage and is almost ideal for this purpose, being non-toxic, a non-irritant and recyclable. Detailed investigations have demonstrated that by varying particle size, particle structure and surface texture, the efficacy of oil removal from feathers and plumage can be successfully manipulated. In this regard, it is possible to identify a grade of iron powder whereby, within experimental error, effectively 100% removal of a variety of fresh contaminants from different matrices, including feathers, can be achieved. Our investigations have been extended to the application of such particles to the successful removal of tarry and weathered/tarry contamination. The results of these investigations have indicated that, for such contaminants, removals ranging from 97–99% may be achieved. Magnetic particle technology may also be adapted for the screening of pre-conditioning agents that can further assist in the removal of tarry and weathered/tarry contamination from feathers. These investigations suggest that magnetic particles could have an important role to play in environmental remediation and wildlife rehabilitation as a clean and effective technology.     

ANALYSIS OF LAS,ABS AND COMMERCIAL DETERGENTS BY TWO-PHASE TITRATION1

ABSTRACT: A two-phase titration method was developed and evaluated to determine the concentration of linear alkylate sulfonate (LAS), branched-chain alkyl benzene sulfonate (ABS), dishwashing detergents, and laundry detergents in water. This method is capable of quantitatively determining anionic surfactants in either fresh water or saline water and it is therefore superior to the widely used Methylene Blue Method. To simplify the titration method for adoptation to remote field utilization, a field test kit was developed. This test kit includes only a separatory funnel, a titration burette, a set of liquid measuring apparatus, and some chemicals. Emphasis was placed on compactness of the kit and simplicity in the test manipulation, so that its operation can be performed by relatively unskilled wastewater monitoring personnel.     

Orientation in Cave-Dwelling wood rats

Summary Allegheny wood rats (Neotoma floridana magister) are occasionally found beyond the light penetration zone in caves. The means of orientation used by cave-trapped rats were studied using a radial maze and double-platform jumping tasks. The effects of various sensory manipulations upon their performances were evaluated, including visual deprivation, reversible deafening, control of chemical cues, and vibrissae trimming. The rats performed best when visible light was available, but they were able to do the tasks in the absence of light as long as their hearing was intact. Manipulation of other sensory cues had no effect. Intact animals seldom produced sounds when ambient sounds were available, but when these were very soft they did produce nonvical sounds. It appears that these cave-dwelling wood rats use acoustic means of orientation in the dark and that they are able to use some environmental sounds when these are available.     

VARIABILITY IN MEASURES OF MACROINVERTEBRATE COMMUNITY STRUCTURE BY STREAM REACH AND STREAM CLASS1

ABSTRACT: Macroinvertebrate community data collected from streams in Wyoming were assessed at various scales: within one stream reach, between stream reaches within one stream, between streams, and between stream classes. Fourteen indices including number of individuals/m², biomass/m², number of taxa, Shannon's diversity index, and functional feeding group ratios were used to compare macroinvertebrates by stream reach and stream class. Statistical analysis indicated that for five of the 14 indices, significant variability occurred between macroinvertebrate communities within one reach. For two of the remaining nine indices there was significant variability between communities from several reaches within the same stream. For seven of the nine indices, there was significant variability among macroinvertebrate communities from streams of the same class. Variability among the macroinvertebrate communities from the three stream classes was significantly different for seven of the nine indices. ANOVA results suggest that macroinvertebrate communities from different samples within one reach and between reaches within one stream were more comparable than those from different streams and different stream classes.     

Maternal provisioning of sequestered defensive steroids by the Asian snake <Emphasis Type="Italic">Rhabdophis tigrinus</Emphasis>

Summary.   Rhabdophis tigrinus obtains defensive steroids (bufadienolides) from its diet and sequesters those compounds in specialized structures on its neck known as nuchal glands. Hatchling snakes lacking these steroids must acquire them from toads consumed as prey. Here we show that females provision bufadienolides to their offspring in amounts correlated to the quantity in their own nuchal glands; thus, chemically protected mothers produce defended offspring. Bufadienolides can be provisioned to embryos via deposition in yolk and by transfer across the egg membranes within the oviducts. Maternally provisioned bufadienolides persist in the nuchal glands of juvenile snakes from the time of hatching in late summer until the following spring, when toads of ingestible size become abundant. Therefore, maternal provisioning may provide chemical protection from predators for young R. tigrinus in the absence of dietary sources of bufadienolides.     

Seed dispersal of desert annuals

We quantified seed dispersal in a guild of Sonoran Desert winter desert annuals at a protected natural field site in Tucson, Arizona, USA. Seed production was suppressed under shrub canopies, in the open areas between shrubs, or both by applying an herbicide prior to seed set in large, randomly assigned removal plots (10-30 m diameter). Seedlings were censused along transects crossing the reproductive suppression borders shortly after germination. Dispersal kernels were estimated for Pectocarya recurvata and Schismus barbatus from the change in seedling densities with distance from these borders via inverse modeling. Estimated dispersal distances were short, with most seeds traveling less than a meter. The adhesive seeds of P. recurvata went farther than the small S. barbatus seeds, which have no obvious dispersal adaptation. Seeds dispersed farther downslope than upslope and farther when dispersing into open areas than when dispersing into shrubs. Dispersal distances were short relative to the pattern of spatial heterogeneity created by the shrub and open space mosaic. This suggests that dispersal could contribute to local population buildup, possibly facilitating species coexistence. Overall, these results support the hypothesis that escape in time via delayed germination is likely to be more important for desert annuals than escape in space.