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Lindsey Dixon

Bio: Lindsey Dixon is an academic researcher. The author has contributed to research in topics: Arid & Vegetation. The author has an hindex of 3, co-authored 5 publications receiving 82 citations.
Topics: Arid, Vegetation, Wetland, Floodplain, Habitat

Papers
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ReportDOI
01 Nov 2011
TL;DR: In this paper, a list of floras and field guides for each USACE region Alaska, Arid West, Atlantic and Gulf Coastal Plain, Caribbean, Eastern Mountains and Piedmont, Great Plains, Midwest, Northcentral and Northeast, Pacific Islands, and Western Mountains, Valleys and Coast is presented.
Abstract: : Over the past few years, a series of Regional Supplements to the 1987 U.S. Army Corp of Engineers (USACE) Wetland Delineation Manual have been published, and currently the National Wetland Plant List is being updated. To support these efforts, we generated a list of floras and field guides for each USACE region Alaska, Arid West, Atlantic and Gulf Coastal Plain, Caribbean, Eastern Mountains and Piedmont, Great Plains, Midwest, Northcentral and Northeast, Pacific Islands, and Western Mountains, Valleys and Coast. Each list includes regional floras, state floras, local floras, regional field guides, state field guides, and local field guides. We also prepared a list of floras and field guides that cover the entire U.S. This list is divided into the following categories: forbs, shrubs, trees, grasses and sedges, ferns, orchids, cacti and agave, and references and help guides. The flora and field guide lists can serve as tools for wetland delineation and restoration, assigning of wetland indicator statuses to vegetation species, and other vegetation activities.

63 citations

01 Jul 2011
TL;DR: In this paper, the authors provide an analysis of how gage data may be utilized in determining the Ordinary High Water Mark (OHWM) on ephemeral and intermittent streams in the Arid West using the physical features of the channel.
Abstract: : The Ordinary High Water Mark (OHWM) defines the lateral extent of non-wetland waters and is regulated as Waters of the United States under Sec. 404 of the Clean Water Act. Previous research has developed a reliable and repeatable methodology for identifying the OHWM on ephemeral and intermittent streams in the Arid West using the physical features of the channel (Lichvar and McColley 2008, Curtis and Lichvar 2010). This study expands upon the previous reports by providing an analysis of how gage data may be utilized in OHW determinations. We clarify the methodology for using gage data, review the potential errors encountered in developing a stage discharge relationship, compare the position of the gage-predicted OHWM to the field OHW signature, and determine the recurrence interval and flow duration of OHW events. The field OHW signature often is not associated with a 2-year flood event like many assume, but ranges from 1- to 15.5-year flood event. This large variation in recurrence intervals for the field OHWMs makes it impossible to define the frequency of the ordinary high flow from gage data because the OHW event is unique to each channel.

9 citations

ReportDOI
01 May 2009
TL;DR: In this paper, aerial photos and stream gauge data for eight ephemeral and intermittent stream channels in the Arid West were analyzed to determine vegetation and channel morphology responses, and the results consistently show that the majority of work, whether it affects vegetation or channel morphology, occurs within the bankfull channel and active floodplain.
Abstract: : "Waters of the United States" (WoUS) are regulated by the U.S. Army Corps of Engineers under Section 404 of the Clean Water Act (33 U.S.C. 1344). The Corps lateral jurisdictional extent in Arid West stream channels is the upper level of the ordinary high water (OHW). The channel shape, fluvial textures, and vegetation patterns of these arid stream channels are heavily influenced by short-term, high-intensity or "flashy" events, which create distinctive physical features and vegetation responses. To determine vegetation and channel morphology responses, sequential aerial photos and stream gauge data for eight ephemeral and intermittent stream channels in the Arid West were analyzed. The observed patterns associated with various discharge event levels are consistent with the Corps OHW delineation manual. The use of remote sensing resources provides another critical support tool for delineating the extent of the OHW in Arid West stream channels. The results of this study consistently show that the majority of work, whether it affects vegetation or channel morphology, occurs within the bankfull channel and active floodplain. This study also showed that the terrace floodplain maintained its vegetative and morphology composition with discharges as large as an 18.7-year flood event, the largest we studied. Data analyzed by flood events support the theory that the bankfull and active channels of intermittent and ephemeral streams in the Arid West function as one channel and that the outer boundary of this single channel represents the extent of the OHW.

7 citations

ReportDOI
01 Jun 2007
TL;DR: In this paper, a combination of literature reviews and recorded species data from previous studies for six specialty habitats are presented and discussed; the species groups are playa edge species, dry wash species and dry wash phreatophytes.
Abstract: : The U.S. Army Corps of Engineers is currently regionalizing and updating the national wetland delineation manual. This manual will use new ecosystem boundaries for the nation. A separate effort by the Corps will update the National Wetland Plant List within these same new ecosystem boundaries. The Arid West is an area of particular interest in the revision of the plant list because of the problematic indicator statuses for certain groups of plants. Many species in the Arid West have morphological and physiological adaptations that allow them to occur in specialized habitats, ranging from wetlands to uplands. In delineations, the indicator status of these species is not always accurate for the specific location. A combination of literature reviews and recorded species data from previous studies for six specialty habitats are presented and discussed; the species groups are playa edge species, dry wash species, dry wash phreatophytes, hygro-halophytes, xero-halophytes, and phreatophytes with salt tolerance. A total of 421 species, with 93 of those species shared in more than one habitat type, are reported, including 48 playa species, 346 dry wash species, 62 dry wash phreatophytes, 32 hygro-halophytes, 47 xero-halophytes, and 17 phreatophytes with salt tolerance. The list for each specialized habitat will be used to better understand species ecology and occurrences across the region and will ultimately help in assigning and increasing the reliability of wetland plant indicator statuses.

2 citations

ReportDOI
01 Jun 2012
TL;DR: In this paper, the potential for regulating wet boulder fields as wetlands or other Waters of the US under Section 404 of the Clean Water Act was evaluated and two boulder fields in Maine were monitored during the 2011 growing season and documented the presence/absence of hydric soil, wetland hydrology, hydrophytic vegetation, and OHP indicators.
Abstract: : We evaluated the potential for regulating wet boulder fields as wetlands or other Waters of the US under Section 404 of the Clean Water Act. We monitored hydrology in two boulder fields in Maine during the 2011 growing season and documented the presence/absence of hydric soil, wetland hydrology, hydrophytic vegetation, and Ordinary High Water Mark (OHWM) indicators. The wetland hydrology criterion was statistically associated with the presence of primary hydrology indicator C4, hydric soils, FACU-dominated wetland, and a separation between the folist layer and the soil surface. The occurrence of hydrophytic vegetation and the combined use of primary and secondary hydrology indicators were not associated with the wetland hydrology criterion. Wet boulder fields should be delineated as wetland/nonwetland mosaics that contain problematic wetland types. We strongly suggest discontinuing the use of secondary hydrology indicators and primary indicator B8 (sparsely vegetated concave surface) in wet boulder fields. Alpha,alpha-dipyridyl paper strips are the most accurate method for determining if a primary hydrology indicator is present. We recommend applying this test several times over fourteen days. IRIS tubes and hydric soil indicators are reliable, but we suggest that alpha,alpha-dipyridyl paper strips be used to confirm a determination of nonhydric soil when a soil lacks a hydric soil indicator.

2 citations


Cited by
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Book
01 Jan 2012
TL;DR: The most popular design of experiments (DOE) book is the 5E of as mentioned in this paper, which is the most recent version of the book and has been updated several times over the last four years.
Abstract: This is probably the most popular design of experiments (DOE) book. It is unquestionably the leading DOE book in industry. So I am excepting it from the usual disdain I show for the Ž fth edition (5E) of any book, even though it follows the fourth edition (4E) by only four years. See Grice (2000) for a report on the 4E. Very likely this book bears little resemblance to the Ž rst edition way back in the 1970s. The author has taken particular care with this latest edition to reorganize the book to be consistent with modern DOE practice rather than classical DOE presentation. The primary change has been to move the chapters on regression modeling and response surface methods forward in the book. In the 4E these were the last two chapters in the book. In the 5E they follow the chapters on factorial and fractional factorial designs. Three chapters on “other designs” now close out the book. This certainly gives the book a better  ow for industry short courses. Perhaps these will simply be referenced as arcane methods in the sixth edition! Other production values in the book also continue to improve. There are many high-quality graphical displays. There is much use of printouts from Minitab and Design-Expert. A student version of Design-Export comes with the book. There is also an instructor’s CD-ROM with supplemental material to make the book suitable for more advanced courses. There is the now-essential Web site that has more information to help students and instructors. Perhaps if I were teaching DOE for master’s-level statisticians, the recent book by Dean and Voss (1999), reviewed by Amidan (2000), would be my choice. However, for most other audiences this is the complete DOE book. Industrial statisticians should get a copy of the new version and ensure its exposure to the relevant people in their organization.

355 citations

Journal ArticleDOI
08 May 1964-Science

137 citations

Journal ArticleDOI
01 Nov 1940-Nature
TL;DR: Fassett as discussed by the authors presented a Manual of Aquatic Plants for the identification of aquatic plants in sterile as well as in flowering or fruiting conditions, and the species included in the Manual are those occurring in the region from Minnesota to Missouri and eastward to the Gulf of St. Lawrence and Virginia.
Abstract: NOTWITHSTANDING the relative uniformity of their environment, aquatic plants exhibit a remarkable variety of form and constitute a very distinct biological group comprising a considerable number of quite unrelated families. An extensive literature already exists relating to the special features of their morphology and ecology; but apart from monographs on certain genera, the group as a whole has not been analysed systematically with the view of simplifying identification. For various reasons the recognition of aquatic species is not always easy and the present work by Prof. Fassett is intended to make as simple as possible the identification of aquatic plants in sterile as well as in flowering or fruiting conditions. The species included in the Manual are those occurring in the region from Minnesota to Missouri and eastward to the Gulf of St. Lawrence and Virginia. Though the area is thus restricted, many plants are dealt with which are familiar to botanists outside America. A Manual of Aquatic Plants By Prof. Norman C. Fassett. Pp. vii + 382. (New York and London: McGraw-Hill Book Co., Inc., 1940.) 26s.

86 citations