News from Scientists at the USGS Patuxent Wildlife Research Center
Thursday, July 25, 2002
| Patuxent
Scientist Allen Invited to Present Seminar at the Geological
Mapping of Atlantic Coastal Parks Workshop at Canaveral National
Seashore, Florida
Jim Allen, Coastal Geomorphologist at PWRC-Boston, was invited to a Geological Mapping of Atlantic Coastal Parks Workshop in late June at Canaveral National Seashore, Florida by the National Park Service. He presented a review of the northeastern park context of landscape forms and processes and contributed vocally to the scientific assessment of other parks as well. During this trip, Jim also updated an old coastal dune retreat monitoring system after a decade of inactivity and did a GPS survey of the shoreline at Cape Canaveral after getting security clearance by NASA to do a shoreline change threat assessment for infrastructure at the Kennedy Space Center. An immediate result is a new park (and interdepartmental program) to support natural and national resource feature monitoring at a semi-annual frequency (and after major storms) for shoreline threat analysis, including barrier breaching policy.
Aerial photo of CANA (called Apollo Beach locally) with the Vehicle Assembly Building in the foreground. Note the transportation routes out to Shuttle Pad 39 A and B, and the very thin natural buffer between the ocean beyond and these nationally important structures which are now threatened by shoreline retreat and loss of dune morphology. Contact: James Allen 617-223-5058 |
Sauer
and Link Publish Article Entitled "Hierarchical Modeling of
Population Stability and Species Group Attributes from Survey
Data"
Sauer, J. R., and W. A. Link. Hierarchical Modeling Of Population Stability And Species Group Attributes From Survey Data. Ecology 83 (6):1743-1751. Abstract: Many ecological studies require analysis of collections of estimates. For example, population change is routinely estimated for many species from surveys such as the North American Breeding Bird Survey (BBS), and the species are grouped and used in comparative analyses. We developed a hierarchical model for estimation of group attributes from a collection of estimates of population trend. The model uses information from predefined groups of species to provide a context and to supplement data for individual species; summaries of group attributes are improved by statistical methods that simultaneously analyze collections of trend estimates. The model is Bayesian; trends are treated as random variables rather than fixed parameters. We use Markov Chain Monte Carlo (MCMC) methods to fit the model. Standard assessments of population stability cannot distinguish magnitude of trend and statistical significance of trend estimates, but the hierarchical model allows us to legitimately describe the probability that a trend is within given bounds. Thus we define population stability in terms of the probability that the magnitude of population change for a species is less than or equal to a predefined threshold. We applied the model to estimates of trend for 399 species from the BBS to estimate the proportion of species with increasing populations and to identify species with unstable populations. Analyses are presented for the collection of all species and for 12 species groups commonly used in BBS summaries. Overall, we estimated that 49% of species in the BBS have positive trends and 33 species have unstable populations. However, the proportion of species with increasing trends differs among habitat groups, with grassland birds having only 19% of species with positive trend estimates and wetland birds having 68% of species with positive trend estimates. Contact: John R. Sauer 301-497-5662 |
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HiLites Contact: B.H. Powell, USGS Patuxent Wildlife Research Center, 301-497-5782 See Previous HiLites: |
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