Ecological Assessments of the Lesser Prairie-chicken (Tympanuchus pallidicinctus) in Southeastern New Mexico
Type of Degreedissertation
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In this study of lesser prairie-chickens (Tympanuchus pallidicinctus), I constructed artificial leks using audio playback (aural stimuli) and decoys (visual stimuli) on active leks, as well as on abandoned lekking locations to examine the effect of aural and visual cues from conspecifics on daily patterns of attendance on active and abandoned lekking locations during the breeding season. I monitored 10 active leks for 6 consecutive days; 3 days without audio playback and decoys followed by 3 days with audio playback and decoys. I also monitored 10 abandoned lekking locations. Attendance on active leks in absence of additional stimuli did not differ significantly from attendance on these leks with additional aural and visual stimuli. Use of audio playback and decoy stimuli attracted 1-3 birds to 6 of 10 abandoned lekking locations. Behavioral observations and patterns of attendance indicated that audio playback and decoys stimulated increased activity and duration of displaying at leks, and attracted birds to abandoned lekking locations. Use of audio playback and decoys in monitoring and management of small populations of lesser prairie-chickens was also examined. I examined 32 abandoned lekking locations and one active lek in southeastern New Mexico. I used decoys of lesser prairie-chickens and an audio system to broadcast sounds of displays to simulate an active lek on abandoned lekking locations. Locations were in areas near reported sightings of lesser prairie-chickens and where active leks were no longer known to exist. These artificial leks were monitored for 3 consecutive days with audio playback and decoy stimuli present. Of 32 abandoned lekking locations monitored, lesser prairie-chickens were observed on five lekking locations. Observation of individuals on three of the five locations appeared to be in response to audio playback, whereas observations on two locations occurred in absence of audio playback and decoys. Results offered evidence that lesser prairie-chickens respond to presence of conspecifics and may use attraction by conspecifics to select breeding habitats. I also assessed vegetative characteristics of pastures associated with active leks and pastures associated with abandoned lekking locations to determine which characteristics of habitat were associated with areas used by lesser prairie-chicken. Data provided by J. L. Hunt were analyzed using logistic regression and resulting models indicated that habitat characteristics for lesser prairie-chickens had a positive correlation with Andropogon, Aristida, Prosopis, Quercus, and Senecio; and a negative correlation with Artemesia, Eriogonum, Muhlenbergia, Panicum, forbs, and bare ground. Results are symptomatic of the negative effects of overgrazing and treatment with herbicides. Finally, I examined characteristics of 17 Habitat Evaluation Areas (HEAs) established by the Bureau of Land Management in southeastern New Mexico. Composition of vegetation on HEAs consisted primarily of shinnery oak (Quercus havardii), sand dropseed (Sporobolus cryptandrus), and purple threeawn (Aristida purpurea), and represented 73% of vegetation on HEAs. Most HEAs included shinnery oak, sand dropseed, purple threeawn, and yucca. In addition to vegetation, cover was on average 19% bare ground (range 6-34%) and 37% litter (range 22-60%). Structure matrices of discriminant-function analyses indicated that vegetative cover of HEAs differed from pastures containing active leks primarily in amount of Sporobolus, Cenchrus, and Andropogon. HEAs typically had significantly more Sporobolus and Cenchrus, and less Andropogon than pastures containing active leks. Average vegetative cover of HEAs, as determined from Robel visual-obstruction values, was 20.85 for the 17 HEAs in 2007-2008 (range = 9.93-40.26); 20.37 for the 7 assessed in 2007, and 21.53 for the 10 assessed in 2008. Robel-values decreased for each of 16 HEAs reassessed in 2012 to an average of 14.16, a 30.45% decrease on average (range 10.98-60.16%). Despite the decrease in vegetative cover on HEAs by 2012, cover remained 31.61% greater (P < 0.001), than the average for pastures containing active leks, and 37.50% greater (P < 0.001) than the average for pastures containing abandoned lekking locations. Despite adequate vegetative cover, populations of lesser prairie-chickens have not rebounded.
- Dissertation Final - Lisa McWilliams (04-17-2013).pdf