Browsing by Subject "Grouse"
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Item Habitat relationships of spruce grouse in southeast Alaska(Texas Tech University, 1999-05) Russell, Amy LeeA geographically disjunct subspecies of spruce grouse, the Prince of Wales spruce grouse (Falcipennis canadensis isleibi), occurs on only a few islands in southeast Alaska. Other than limited morphology data, the scientific literature lacked any information on habitat relationships, ecology, and natural history of this subspecies. Moreover, no field studies had been conducted on spruce grouse in a temperate rainforest ecosystem. Thus, habitat relationships could not be readily inferred from the existing literature because the temperate rainforest of southeast Alaska is disfinct from other ecosystems in the range of spruce grouse. Spruce grouse were studied on Prince of Wales and Heceta Islands in southeast Alaska from April 1996-January 1998. Nineteen birds were captured and fitted with radio transmitters. Grouse were radio-tracked throughout the year w ith an emphasis on collecting data during the reproductive period. Habitat data were evaluated at 3 spatial scales (home range, core area, location) using logistic regression. .A logistic model was fitted at the smallest scale of resolution, individual locations. Spruce grouse selected bog and high-volume, old-growth forest habitat and avoided clearcuts. Second-growth forest (15-30 yrs after clearcutting) and scrub forest habitats were used in proportion to their availability. No grouse, however, used large areas of second-growth forest exclusively, indicating that uniform structure may not be suited to all life requisites. Horizontal diversity may be an important component of spruce grouse habitat in southeast Alaska. Forest management practices which encourage horizontal diversity, avoid large patches of uniform structure, and allow connectivity of natural patches across the landscape would be less likely to isolate populations of Prince of Wales spruce grouse.Item Relationship of lesser prairie-chicken density to landscape characteristics in Texas(2012-05) Timmer, Jennifer; Boal, Clint W.; Butler, Matthew J.; Ballard, Warren B.; Whitlaw, Heather A.Ground-based lek surveys have traditionally been used to index trends in prairie grouse populations (Centrocercus and Tympanuchus spp.). However, indices of abundance or density can be fundamentally flawed and techniques that account for incomplete detection should be used. Distance sampling is a common technique used to estimate the density and abundance of animal populations and has been used with aerial surveys to monitor avian populations. With an increase in renewable energy development in native prairies and sagebrush steppe, there is a greater need to effectively monitor prairie grouse populations. One such species, the lesser prairie-chicken (LPC; T. pallidicinctus), has faced significant population declines and is thus, a species of conservation concern. In addition, much of the current and proposed wind energy development in the Great Plains overlaps some of the extant LPC distribution and few peer-reviewed studies have been conducted to investigate this potential threat to LPCs. Hierarchical distance sampling models can relate LPC lek density to landscape features and help predict the potential impact from wind and other energy development on lek density. Thus, the main objectives of our study were to estimate lek density in the LPC range in Texas and model anthropogenic and landscape features associated with lek density. We accomplished this by flying helicopter lek surveys for 2 field seasons and employing a line-transect method developed at Texas Tech University. We inventoried 208, 7.2 km × 7.2 km survey blocks and detected 71 new leks, 25 known leks, and observed 5 detections outside the current LPC range. We estimated 2.0 leks/100 km2 (90% CI = 1.5–2.8 leks/100 km2) and 12.3 LPCs/100 km2 (90% CI = 8.5– 17.9 LPCs/100 km2) for our sampling frame. Our state-wide abundance estimates were Texas Tech University, Jennifer M. Timmer, May 2012 vii 301.9 leks (90% CI = 219.4–415.4 leks) and 1,822.4 LPCs (90% CI = 1,253.7–2,649.1 LPCs). Our best model indicated lek size and lek type (wi = 0.360) influenced lek detectability. Lek detectability was greater for larger leks and natural leks rather than man-made leks. We used hierarchical distance sampling to build spatially-explicit models of lek density and landscape features. The 2 most competitive models included percent shrubland + transmission line (>69kv) density and only percent shrubland (AIC= 943.817, wi = 0.486; AIC = 945.098, wi = 0.256, respectively). We model-averaged our most competitive models and estimated the number of leks in our sampling frame at 245.7 leks (cv = 0.137). Lek density peaked at lower levels of transmission line density and where ≈60% of the landscape was composed of shrubland patches (shrubs <5 m tall comprising ≥20% of the total vegetation). Our state-wide survey efforts provide wildlife managers and biologists with population estimates, new lek locations, and identified spatially-explicit predictions of lek density. Our spatially-explicit models predicted lek density based on percent shrubland and transmission line density, which can be used to predict how lek density may change in response to transmission line development and changes in habitat conditions. This copy has been corrected.