News from Scientists at the USGS Patuxent Wildlife Research Center
Friday, December 20, 2002
| Patuxent
Scientists Link and Sauer Authors of "A hierarchical analysis of population change with application to ceruleean warblers" Link, W. A., and J. R. Sauer. 2002. A hierarchical analysis of population change with application to cerulean warblers. Ecology 83:2832 – 2840. Abstract: Estimation of population change from count surveys is complicated by variation in quality of information among sample units, by the need for covariates to accommodate factors that influence detectability of animals, and by multiple geographic scales of interest. We present a hierarchical model for estimation of population change from the North American Breeding Bird Survey. Hierarchical models, in which population parameters at different geographic scales are viewed as random variables, provide a convenient framework for summary of population change among regions, accommodating regional variation in survey quality and a variety of distributional assumptions about observer effects and other nuisance parameters. Markov chain Monte Carlo methods provide a convenient means for fitting these models, and also allow for construction of estimates of derived variables such as weighted regional trends and composite yearly population indices. We construct an overdispersed Poisson regression model for estimation of trend and year effects for Cerulean Warblers, Dendroica cerulea, accommodating nuisance covariates for observer and start-up effects, and estimating abundance-and area-weighted annual indices at regional and continent-wide geographic scales. A goodness of fit test is also presented for the model. Cerulean Warbers declined at a rate of -3.04 %/year over the interval 1966 - 2000. Contact: Dr. John R. Sauer 301-497-5662 Steinkamp is Regional Editor for North America, Central America and the Caribbean of 3rd Edition of "Waterbird Population Estimates" The 3rd Edition of Waterbird Population Estimates was launched on November 19th, 2002 at the Conference of the Parties to the Ramsar Convention (CoP 8) Meeting in Valencia, Spain. This publication comprises a global overview of 2,271 biogeographical populations of 868 species of waterbirds, and provides the basis of the Ramsar 1% Criterion. Melanie Steinkamp, who served as the Regional Editor for North America, Central America, and the Caribbean, was present to help launch the publication. USGS was publicly recognized at the launch as a key contributor to the 3rd Edition. Copies may be purchased at the Wetlands International Website, http://www.wetlands.org . Contact: Melanie Steinkamp, 301-497-5753 |
Patuxent
Scientist Sparling one of Authors of "Aqueous-phase
disappearance of atrazine, metolachlor and chlorpyrifos in
laboratory aquaria and outdoor macrocosms.
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Mazanti, L., Rice, C., Bialek, K., Sparling, D. Stevenson, C., Johnson, W.E., Kangas, P. and Rheinstein, J. 2003. Aqueous-phase disappearance of atrazine, metolachlor and chlorpyrifos in laboratory aquaria and outdoor macrocosms. Arch Environ Contam Toxicol. 44; 67-76. Abstract: Dissipation processes are described for a combination of commonly used pesticides C atrazine (6-chloro-4-ethylamino-6-iospropylamino-s-triazine), metolachlor (2-chloro-N-[2-ethyl-6-methly-phenyl]- N-[2-methoxy-1 -methylethyl] acetamide, and chlorpyrofios ()-) diethyl O-[3,5,6-trichloro-2-pyridinyl] phosphorothioate] C in a laboratory and outdoor pond systems. Dosing rates and timing were designed to duplicate those common in the mid-Atlantic Coastal Plain, USA. Treatments ranged from 2 and 2.5 mg/L to 0.2 and 0.25 mg/L, respectively for atrazine and metolachlor, and chlorpyrifos was added at 1.0 and 0.1 mg/L in the aquaria and at 0.1 mg/L in the outdoor macrocosms. Chlorpyrifos disappearance was rapid in all of the systems and followed a two-phase sequence. Initial half-lives varied from 0.16 dya to 0.38 day and showed similar rates in the aquaria and the outdoor systems. The second phase of the chlorpyrifos loss pattern was slower (18-20 days) in all the treatments except for the low herbicide treatment in the outdoor test where it was 3.4 days. Compared to the outdoor system, herbicide losses wee much slower in the aquaria, e.g. 150 days for atrazine and 55 days for metolachlor, and no appreciable loss of herbicide was apparent in the high-treated aquaria. In the outdoor systems, the half-lives for the low herbicide treatment were 27 days and 12 days, respectively, for atrazine and metolachlor, and 48 and 20 days, respectively for the high herbicide-treated ponds. Very low levels of CIAT (6-amino-2-chloro-4-iso-propylamino-s-triazine) and CEAT (2-chloro-4-ethylamino-6-ehtylamino- s-triazine), degradation products of atrazine, were observed in the outdoor studies. Contact: Dr. Donald W. Sparling 301-497-5723 |
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