13,293 research outputs found
MP 2012-02
Final report to BP.The Prudhoe Bay oil fields, Alaska were discovered in 1968,
and commercial production commenced in 1977 with the
completion of the Trans-Alaska Pipeline. Oil production has
been declining since 1989, although additional exploratory
drilling continues. Support facilities for oil production are
built on permafrost soils that surface-thaw in summer to form
extensive wetlands composed of moist meadows, sedge marshes,
moist sedge-dwarf shrub tundra, grass marshes, small ponds
and lakes (Walker and Acevedo 1987). To prevent thawing and
subsidence of subsurface, ice-rich soils, gravel pads, 2m (6 ft) or
more thickness have been built to support drilling sites as well as
roads, airstrips and building pads (Kidd et al. 2006). As well sites
are decommissioned, the gravel is wholly or partially removed
resulting in the need for site rehabilitation and/or restoration to
support wetland plants and, in some instances, enhance wildlife
habitat (McKendrick 1991, Jorgenson and Joyce 1994, Kidd et
al. 2004, 2006). Since the 1970s, methods to revegetate arctic wetlands have
included a variety of planting techniques, seed treatments,
seeding with native and non-native species (mostly grasses),
and fertilizer applications (Chapin and Chapin 1980; Bishop
and Chapin 1989, Jorgenson 1988, Kidd and Rossow 1998,
Kidd et al. 2004, 2006, Maslen and Kershaw 1989, McKendrick
1987, 1991, 2000, McKendrick et al. 1980, McKendrick and
Mitchell 1978, Mitchell et al. 1974). Treatments also have
included sprigging and plug transplantation (Kidd et al. 2004,
2006), surface manipulation (Streever et al. 2003), as well as
natural re-colonization (Ebersole 1987, Schwarzenbach 1996).
These methods have been partially successful. The gravelly soils
often are dry, nutrient-poor, and have a higher pH and lower
organic matter content than surrounding soils, so natural recolonization
does not occur readily (Bishop and Chapin 1989,
Jorgenson and Joyce 1994). Methods such as sprigging and plug
transplanting are slow, labor intensive and expensive compared
to direct seeding. Fertilization, especially with phosphorus, is
recommended for long-term survival of plants grown on gravelly
sandy soils (BP Exploration and McKendrick 2004).
Two common species in the arctic coastal wetlands are water
sedge, Carex aquatilis Wahlenb. and cotton sedge, Eriophorum
angustifolium Honck. Carex aquatilis in particular forms large
populations that spread vegetatively by rhizomes and often
dominate these wetland environments (Shaver and Billings
1975). Despite their abundance, these species have not been
considered for revegetation because of poor seed germination
and inadequate information on seed development and viability
(Dr. William Streever, BP Alaska, pers. comm.). Both Carex and
Eriophorum in arctic environments produce abundant seeds, but
seed viability and germination often is low and highly variable
among years and locations (Archibold 1984, Billings and
Mooney 1968, Ebersole 1989, Gartner et al. 1983).
Germination recommendations for both species vary by
location and have included an array of pretreatments such as light, alternating temperatures, cold stratification, scarification,
and high and low temperature dry storage (Amen 1966, Billings
and Mooney 1960, Bliss 1958, Hunt and Moore 2003, Johnson
et al. 1965, Phillips 1954 and Steinfeld 2001). The purpose
of this project was to explore methods of seed germination of
Carex aquatilis and Eriophorum angustifolium, to learn the
conditions for germination and dormancy control mechanisms,
and identify seed treatments that might enhance germination
for eventual use in direct-seeding or plug production for arctic
wetland revegetation
Estimating and Analyzing Demographic Models Using the popbio Package in R
A complete assessment of population growth and viability from field census data often requires complex data manipulations, statistical routines, mathematical tools, programming environments, and graphical capabilities. We therefore designed an R package called popbio to facilitate both the construction and analysis of projection matrix models. The package consists primarily of the R translation of MATLAB code found in Caswell (2001) and Morris and Doak (2002) for the analysis of projection matrix models. The package also includes methods to estimate vital rates and construct projection matrix models from census data typically collected in plant demography studies. In these studies, vital rates can often be estimated directly from annual censuses of tagged individuals using transition frequency tables. Because the construction of projection matrix models requires careful management of census data, we describe the steps to construct a projection matrix in detail.
Graduate Catalog, 1972-1973 & 1973-1974
https://scholar.valpo.edu/gradcatalogs/1007/thumbnail.jp
Review Journals : Molecular From Anonaceae
There are roughly 120 species of the Anona genus, which is found in tropical and subtropical areas. The diversity at the species level and similarity of the leaves, fruits, and stems that are produced as a result of plant cultivation and hybridization create new plants that are difficult to macroscopically identify. The diversity of the genus Anona can be accurately determined using molecular identification. For example, genetic analysis utilizing PCR and the RAPD and AFLP procedures is one way to gather molecular data. In this study, we inform the development of species-specific primers by differentiating the most agronomically interesting Annona species that, until recently, a new formal classification based on molecular phylogenetics has been developed in order to have a quick and precise method of distinguishing Annona between species agronomically
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