Get reliable rangeland science

Concern continues to grow for both declining black-tailed prairie dog (Cynomys ludovicianus) and grassland bird populations in North America. Much of the remaining habitat is rangeland, and understanding community interactions among vegetation, grassland birds, and prairie dogs in a dynamic rangeland setting will be crucial to future management decisions. Therefore, we developed a study geared towards providing a better understanding of how the simultaneous occurrence of prairie dogs and cattle influence the local bird community. Preliminary data was collected May – August of 2012 on bird and vegetation communities both on and off prairie dog towns near McLaughlin, South Dakota. The study site consisted of five pastures, with varying levels of prairie dog occurrence. Season-long cattle grazing (June-October) occurred in four of five pastures. Forty-one (300 m) transects (16 on-town and 25 off) were placed randomly throughout the pastures. Distance sampling was used to survey birds twice on all transects. Vegetation sampling was completed on 21 plots/transect on 24 of 41 transects using modified Daubenmire frames to measure canopy cover, Robel poles to determine visual obstruction, and 10-pinpoint frames to calculate basal cover. Thirty-six bird species were recorded on prairie dog towns and 34 species were observed off dog towns. H' values for birds were attained using the Shannon-Weiner diversity index. Off-town transects were on the high end of typical values with H'=2.33. On-town transects had less species evenness with H'=2.72, which is considered outside the typical H' range of 1.5 to 2.5. Species richness values ranged from 12-25 for on-town transects and 8-24 for off-town transects. Dominant vegetation species for on-town transects included Pascopyrum smithii, Dyssodia papposa, and Sphaeralcea coccinea. Off-town transects were dominated by Pascopyrum smithii, Nassella viridula, and Poa pratensis. On and off-town average maximum live vegetation was 18.6 cm and 46.4 cm tall, respectively.