Author: David William Howerter Publisher: ISBN: Category : Ducks Languages : en Pages : 160
Book Description
Habitat fragmentation often has been cited as a cause for reduced reproductive success of grassland-nesting birds, including ducks, though results of many studies have been equivocal. As remotely sensed habitat data become increasingly available, an increased understanding of how habitat configurations affect demographic parameters will allow wildlife managers to make better decisions about habitat preservation and restoration. We used duck (Anas spp.) nesting data from 15 65-km2 study areas (n=6300 nests) dispersed throughout the aspen (Populus tremuloides) parklands of south-central Canada, to test hypotheses and build models that predict hatching rates and nest-site distributions in relation to landscape features. We constructed separate models using landscape features generated at 3 different spatial extents and using 3 different habitat classification schemes. Generalized linear mixed-modeling techniques were used to model hatching rates, and logistic regression was used to discr.
Author: Duane Bruce Pool Publisher: ISBN: Category : Nest building Languages : en Pages : 112
Book Description
Ducks Unlimited's (DU) mission statement is focused on providing for the annual lifecycle needs of migratory waterfowl. The largest impacts to the success and numbers of continental populations are determined by their activities on the breeding grounds. To model and therefore manage habitats and landscapes for ducks (Anas and Aythya spp.) it is necessary to understand several characteristics of their behavior. This research builds a model of nest site selection from nest probability based on remotely sensed data, presence data and minimum threshold theory. The methods used are applicable to other sensor platforms as well as other target species or phenomenon. Using data compression techniques, logistic regression, and spatial statistical functions (Ripley's k-function, a global k-function, and Multiple Response Permutation Procedure) we tested the observed point patterns and developed a point process model to predict nesting patterns. The application of this type of fine resolution da.
Author: R. Kahler Martinson Publisher: ISBN: Category : Aerial surveys in wildlife management Languages : en Pages : 88
Book Description
Surveying of selected transects from the air and from the ground has been used since 1959 to determine the proportion of waterfowl, by species, that are observed by aerial crews. This method attempts to resolve obvious biases in aerial indexes relating to habitat differences, seasonal differences, aerial crew changes, etc. Assumptions in this method of correction are that (1) the ground crew observed substantially all waterfowl present and (2) the selected comparison transects adequately represent surrounding transects to which the correction is to be applied. This report, utilizing data of 1961 to 1966, reviews the necessity for air:ground correction and evaluates the procedure as a solution to aerial index biases ; problems apparent are lack of representativeness of air:ground transects and inadequate numbers of transects. Lack of representativeness appears in population density and in species composition differences between air:ground and operational transects. The degree to which the numbers of air:ground ratios varies according to areas and according to species. Recommendations to improve the air:ground technique are: (1) make two daily surveys of one aerial pass each, at an interval of at least two hours, in the same direction and at the same time as the adjacent operational transects are surveyed ; (2) make ground counts the day before or day after aerial surveys ; (3) lay out all air:ground comparison transects in the same direction (west-east) as the operational transects ; and (4) match new or relocated transects as nearly as possible to density and species composition of the survey stratum or area they represent.
Author: Kenneth F. Higgins Publisher: ISBN: Category : Grasses Languages : en Pages : 32
Book Description
A sample of 365 stands of seeded nesting cover (mixtures of cool-season grasses and legumes) was studied in the glaciated prairie pothole region during 1977-79. Measurements of species composition, canopy cover, plant height, and visual obstruction values differed with stand age but only in a general way when results from over the entire region were pooled. Maximum values for plant height and visual obstruction occurred once per stand during the first 10 growing seasons. Although the year of maximum growth was variable and unpredictable, stands showed trends of degeneration in height and visual obstruction after the year of maximum growth.
Author: David William Howerter
Author: Jerome H. Stoudt
Author: Allen G. Smith
Author: Duane Bruce Pool
Author: Scott Eugene Stephens
Author: R. Kahler Martinson
Author: 
Author: 
Author: Kenneth F. Higgins
Author: Harold A. Kantrud