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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Pollinating insect responses to grazing intensity, grassland characteristics, and landscape complexity : behaviour, species diversity, and composition /

Sjödin, N. Erik, January 2007 (has links)
Thesis (doctoral)--Swedish University of Agricultural Sciences, 2007. / Thesis documentation sheet inserted. Includes appendix of four papers and manuscripts, two co-authored with others. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.
42

Root herbivory in grasslands and savannas the potential role of June beetle (Phyllophaga spp.; Scarabaeidae) larvae in central Texas plant community structure /

Brumbaugh, Michael Shawn, Fowler, Norma L., Litvak, Marcy E., January 2004 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisors: Norma L. Fowler and Marcy E. Litvak. Vita. Includes bibliographical references. Available also from UMI company.
43

Effects of predators and cattle on ground-nesting grassland birds in southwestern Wisconsin pastures

Nack, Jamie Lynn. January 2002 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 2002. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
44

Revegetation of disturbed semiarid grassland in Canyonlands National Park /

Goldberg, Susan B. January 1993 (has links)
Thesis (M.S.)--Oregon State University, 1994. / Typescript (photocopy). Includes bibliographical references (leaves 48-56). Also available on the World Wide Web.
45

The short-term impacts of burning and mowing on prairie ant communities of the Oak Openings Region

Friedrich, Russell L. January 2010 (has links)
Thesis (M.S.)--University of Toledo, 2010. / Typescript. "Submitted to the Graduate Faculty as partial fulfillment of the requirements for the degree of Master of Science in Biology (Ecology track)." "A thesis entitled"--at head of title. Title from title page of PDF document. Bibliography: p. 38-42 and 51.
46

Influence of nitrogen on below ground dynamics in improved grasslands

Koikkalainen, Riitta Katariina. January 2009 (has links)
Thesis (Ph.D.)--Aberdeen University, 2009. / Includes bibliographical references.
47

Étude de la végétation des pelouses alpines au Parc national suisse

Galland, Pierre. January 1982 (has links)
Thesis (Ph. D.)--Université de Neuchâtel, 1982. / At head of title: Université de Neuchâtel, Institut de botanique. Projet soutenu par le Fonds national de la recherche scientifique, requête no 3.628-0.75. Figures 26-27, tableaux 10-11 on 4 leaves in pocket. "Supplement au Travaux de l'Institut de botanique no 29/1982"--Label on cover. Description based on print version record. Includes bibliographical references (p. 171-177).
48

The influence of agricultural land use and physiography on grassland birds in the Wisconsin driftless area

Renfrew, Rosalind B. January 1999 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1999. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
49

Nesting Ecology of Ducks in Dense Nesting Cover and Restored Native Plantings in Northeastern North Dakota

Haffele, Ryan D. 01 May 2012 (has links)
Conservation efforts to increase duck production have led the United States Fish and Wildlife Service to restore grasslands with multi-species (3-5) mixtures of cool season vegetation often termed dense nesting cover (DNC). The effectiveness of DNC to increase duck production has been variable, and maintenance of the cover type is expensive. In an effort to decrease the costs of maintaining DNC and support a more diverse community of wildlife, restoration of multi-species (16-32) plantings of native plants has been explored. Understanding the mechanisms of nest site selection for nesting ducks within these plantings is important in estimating the efficiency of this cover at providing duck nesting habitat and determining appropriate management techniques. I investigated the vegetation characteristics between the 2 aforementioned cover types in the prairie pothole region of North Dakota, USA to see if native plantings provide the same vegetative structure to nesting hens as DNC. I also determined the nest density and nest success of upland nesting waterfowl in the cover types to determine if restored native plantings are providing the same nesting opportunity as DNC. Within each cover type I identified vegetation characteristics at nest sites of the 5 most common nesting species and compared them to random locations and within species to identify species specific factors in nest site selection. I located 3,524 nests (1,313 in restored-native vegetation and 2,211 in DNC) of 8 species in 2010-11. Native plantings had an average of 6.17 (SE = 1.61) nests/ha while DNC had an average of 6.71 (0.96) nests/ha. Nest densities were not different between cover types for the 5 most common nesting species. In 2010, nest success differed between cover types with restored-native plantings having 48.36% (SE = 2.4) and DNC having 42.43% (2.1) success. In 2011, restored-native planting success dropped considerably to 13.92% (1.7) while DNC success was similar to 2010 at 37.10% (1.7) The variability in nest success appeared to be impacted by late season success, as native plantings had similar success early in the nesting season, but much lower success later in the nesting season in both years. Vegetation data indicated no structural difference between cover types in 2010; however, a difference was detected during the late sampling period in 2011, with native plantings having shorter vegetation at random locations than DNC during this sampling period. In general ducks selected nest sites with greater leaf litter and denser, taller cover compared to random sites, however, vegetation density and height selection varied among species. Gadwall and mallards selected the tallest, densest vegetation, with northern pintail, blue-winged teal, and northern shovelers selecting vegetation of intermediate height and density. My results indicate native plantings are able to support similar densities of nests, but have great variability in nest success from year to year. In years with low nest success, native plantings may create an ecological sink as hens were not able to identify low quality patches and nested in similar densities despite lower success.
50

Grassland dynamics on revetments at RAF Caerwent, Monmouthshire, South Wales

Savage, Bernard S. January 2001 (has links)
A chronosequence method was used to study plant community changes over successional time in a replicated design over an interval of 56 years. Artificial earthworks (revetments) constructed in 1939 and 1968 within a military manufacturing facility have been maintained under a constant regime of regular cutting and biomass removal. Predictions of species and community level change based on models of Odum, Grime and Peet are tested. Aspect and time are shown to be the major explanatory factors determining vegetational differences between samples. Diversity was seen to be significantly lower in older communities in conflict with Odum's model of community development. Partitioning of community structure by relative abundance suggests that the direction of development is contingent on physical conditions. Change in species types from ruderal to stress tolerators is consistent with Grime's successional model but is supported only weakly and by a minority of the species present. Feet's model of competitive sorting is strongly supported at the l-3m scale but refuted at larger scales. It is apparent that older communities show a tendency towards divergence in structure. The influence of spatial factors on ecological research methods is examined and discussed and it is suggested that development of predictive community models will require a recognition of the multiple levels of community structure and the multiple scales of interactions between their components.

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