The North American Dragonflies of the Genus Aeshna [microform] PDF Download
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![The North American Dragonflies of the Genus Aeshna [microform] PDF](https://books.google.com/books/content/images/frontcover/3aY8zQEACAAJ?fife=w150-h200)
Author: Edmund Murton Walker
Publisher:
ISBN: 9780665988011
Category : Dragonflies
Languages : en
Pages : 213
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Book Description
![The North American Dragonflies of the Genus Aeshna [microform] PDF](https://books.google.com/books/content/images/frontcover/3aY8zQEACAAJ?fife=w80-h100)
Author: Edmund Murton Walker
Publisher:
ISBN: 9780665988011
Category : Dragonflies
Languages : en
Pages : 213
Get Book Here
Book Description
Author: Edmund Murton Walker
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Edmund M.. Walker
Publisher:
ISBN:
Category :
Languages : en
Pages : 213
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Book Description
Author: Edmund Murton Walker
Publisher:
ISBN:
Category : Dragonflies
Languages : en
Pages : 302
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Book Description
Author: Gábor Horváth
Publisher: Springer Science & Business Media
ISBN: 3662093871
Category : Science
Languages : en
Pages : 465
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Book Description
The subject of this volume is two-fold. First, it gathers typical polarization patterns occurring in nature. Second, it surveys the polarization-sensitive ani mals, the physiological mechanisms and biological functions of polarization sensitivity as weIl as the polarization-guided behaviour in animals. The monograph is prepared for biologists, physicists and meteorologists, espe cially for experts of atmospheric optics and animal vision, who wish to under stand and reveal the message hidden in polarization patterns of the optical environment not directly accessible to the human visual system, but measur able by polarimetry and perceived by many animals. Our volume is an attempt to build a bridge between these two physical and biological flelds. In Part I we introduce the reader to the elements of imaging polarimetry. This technique can be efflciently used, e. g. in atmospheric optics, remote sens ing and biology. In Part 11 we deal with typical polarization patterns of the natural optical environment. Sunrise/sunset, clear skies, cloudy skies, moonshine and total solar eclipses all mean quite different illumination conditions, wh ich also affect the spatial distribution and strength of celestial polarization. We pre sent the polarization patterns of the sky and its unpolarized (neutral) points under sunlit, moonlit, clear, cloudy and eclipsed conditions as a function of solar elevation. The polarization pattern of a rainbow is also shown. That part of the spectrum is derived in which perception of skylight polarization is optimal under partly cloudy skies.
Author: Bernd Redecker
Publisher: Springer Science & Business Media
ISBN: 9783540429203
Category : Science
Languages : en
Pages : 478
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Book Description
One of the main problems and aims of nature conservation in Europe is to protect semi-open landscapes. The development during the past decades is characterized by an ongoing intensivation of land use on the one hand, and an increasing number of former meadows and pastures lying fallow caused by changing economic conditions on the other hand. In several countries the estabishment of larger "pasture landscapes" with a mixed character of open grassland combined with shrubs and forests has been recognized as one solution to this problem. The book gives an overview of the European projects concerning to this topic - nature conservation policy and strategies, scientific results and practical experiences creating large scale grazing systems.
Author: James George Needham
Publisher:
ISBN:
Category : Nature
Languages : en
Pages : 966
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Book Description
Author: Roland Bobbink
Publisher: Springer Science & Business Media
ISBN: 3540331891
Category : Science
Languages : en
Pages : 336
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Book Description
This book gives a broad and well-integrated overview of recent major scientific results in wetland science and their applications in natural resource management. After an introduction into the field, 12 chapters contributed by internationally known experts summarize the state of the art on a multitude of topics. The coverage is divided into three sections: Functioning of Plants and Animals in Wetlands; Conservation and Management of Wetlands; and Wetland Restoration and Creation.
Author: Edward Maltby
Publisher: Thomas Reed Publications
ISBN:
Category : Biodiversity conservation
Languages : en
Pages : 186
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Book Description
Author: Kenneth J. Tennessen
Publisher: Springer
ISBN: 3319977768
Category : Science
Languages : en
Pages : 627
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Book Description
This monograph is the first of its kind devoted entirely to the dragonfly nymphs of North America north of Mexico, the focus being accurate identification of the 330 species of Anisoptera that occur in the region. Nymphal external morphology is described and illustrated in detail, and all terms needed to navigate the dichotomous keys are defined. Species are tabulated with references that provide the most detailed, accurate descriptions for each; species that are inadequately described are so indicated. The key separating the seven families in the region contains several new characters. The families are then covered separately: Aeshnidae (13 genera), Gomphidae (17 genera), Petaluridae (2 genera), Cordulegastridae (2 genera), Macromiidae (2 genera), Corduliidae (7 genera), and Libellulidae (29 genera). Each family is further characterized, followed by a generic key. A drawing of the habitus and diagnostic details for each genus are provided, along with additional diagnostic remarks and notes on habitat and life cycle; for each genus, a map shows its geographic distribution in North America. Full-grown nymphs of all known species of each genus are keyed and diagnosed; characters that apply to earlier instars are noted. Morphological variation in character states was analyzed in order to assess the reliability of previously utilized characters and to discover new characters. Most of the characters used to distinguish all levels of taxa are illustrated; a total of 702 figures, comprising 1,800 original drawings, along with selected photographs where necessary for clarity, accompany the keys. Measurements of total length, head width, and other variables for each species are provided in tables. Difficulties with past keys and descriptions, including errors, omissions and other shortcomings, are addressed. The importance of nymph characters in helping solve generic and specific distinctions and their role in phylogenetic studies is emphasized. Methods for collecting, rearing, and preserving dragonfly nymphs and exuviae are presented. The final chapter discusses research opportunities on North American Anisoptera nymphs, including taxonomic needs, studies on structure and function, life history and microhabitat, water quality indices and conservation efforts. The habitus drawings of all genera are arranged according to family in five plates (Appendix I); although the book is intended as a lab manual, these plates conveniently allow for comparison based on nymph shape making field identification to genus possible in many cases. Appendix II contains a brief history of dragonfly nymph studies in North America. A glossary and an index to scientific names are included.
