Investigation into the decline of populations of the lesser prairie-chicken (Tympanuchus pallidicinctus Ridgway) in southeastern New Mexico

Populations of lesser prairie-chickens (Tympanuchus pallidicinctus Ridgway) have declined sharply across the geographic range of the species, including southeastern New Mexico. Suggested causes include drought, conversion of habitat to agricultural use, improper gazing management, chemical control of shinnery oak, hunting, and disturbance and fragmentation of habitat caused by petroleum development. The Bureau of Land Management, which administers public lands that include habitat of lesser prairie-chickens, is required to manage for the conservation of the species and to ensure that their actions do not contribute to the need to list the species as threatened or endangered. As a partial response to this requirement, the Bureau of Land Management authorized and provided support for the study documented herein.; Lesser prairie-chickens use a breeding system in which males display at leks to attract females. A lek is an area where males set up and defend territories on which they perform elaborate mating displays. Most activity, including nesting and brood-rearing, takes place near the lek. For this reason, the lek is the focal point of much research on lesser prairie-chickens. This study compared several components of habitat at active and abandoned leks within the Carlsbad Field Office of the Bureau of Land Management, New Mexico. These components were then analyzed with factor analysis to determine which contributed most to decline in populations. Management recommendations based on the findings are included.; Several vegetative characters of active and abandoned leks of lesser prairie-chickens were measured using the line-point sampling method. Vegetative cover and composition of active leks and associated control points were significantly different from those of abandoned leks and control points in all 3 years of the study. Active leks and control points had significantly more Andropogon and less Sporobolus than did abandoned leks and control points. Abandoned leks were more likely to be near Prosopis >60 cm in height than were active leks. Vegetative structure as measured by the Robel method was not significantly different for active and abandoned leks. Results are symptomatic of overgrazing, which is detrimental to populations of lesser prairie-chickens.; Several aspects of petroleum development were measured at active and abandoned leks, including number of active and inactive oil wells within 1.6 km, presence or absence of power lines, and length of road within 1.6 km. (Abstract shortened by UMI.)...