Keystone species have large impacts on community and ecosystem properties, and create important ecological interactions with other species. Prairie dogs (Cynomys spp.) and banner-tailed kangaroo rats (Dipodomys spectabilis) are considered keystone species of grassland ecosystems, and create a mosaic of unique habitats on the landscape. These habitats are known to attract a number of animal species, but little is known about how they affect lizard communities. Our research evaluated the keystone roles of prairie dogs and kangaroo rats on lizards at the Sevilleta National Wildlife Refuge in central New Mexico, USA. We evaluated the impacts of these rodents on lizard communities in areas where prairie dogs and kangaroo rats co-occurred compared to areas where each rodent species occurred alone. Our results demonstrate that prairie dogs and kangaroo rats have keystone-level impacts on these lizard communities. Their burrow systems provided important habitats for multiple lizard species, especially the lesser earless lizard (Holbrookia maculata). At the landscape-scale, the total number of lizards was two-times greater on the where both prairie dogs and banner-tailed kangaroo rats co-occurred than where only kangaroo rats occurred.
The landscape-scale plots were 180 m x 180 m. Lizards were visually sampled along strip transect lines established along each gridline of the landscape-scale plots, using a 5 x 5 grid array. Strip transects on the landscape-scale plots measured 1 m x 30 m.
Methods & Experimental Design
Landscape-scale plots: We compared lizards on plots occupied by: 1) both species (Pdog+Krat plot); 2) only kangaroo rats (Krat plot); and 3) both species, but where prairie dogs inhabited one half of the plot and kangaroo rats inhabited the other half (Transition plot).Field Methods
Lizards were sampled by walking slowly along each transect, and individuals were counted and identified to species. Lizards were always sampled in the morning between 9:00 - 11:00 am. Lizards were sampled throught the springand summer from spring 2000 through late summer 2002.
These metadata were obtained from Ana Davidson in a Word File. The data are in an Excel file that accompanies the metadata. -- KLV 1/31/2006
Additional Information on the personnel associated with the Data Collection / Data Processing
Field Crew Member: Julie McIntyre
Additional Study Area Information
Study Area Name: Pino Gate
Study Area Location: The study site was located near the base of the Los Pinos mountains and directly adjacent to the nothern fencline of the SNWR at Pino Gate
Elevation: 1600 m
Vegetation: Burrograss (Scleropogon brevifolius), sand dropseed (Sporobolus ryptandrus), and black grama (Bouteloua eriopoda) were the dominant vegetation.
Soils: Deep clayey loam soils
Geology: On an upper bajada slope, in a broad swale
Climate: Long-term mean annual precipitation is 243 mm, about 60% of which occurs during the summer. Long-term mean monthly temperatures for January and July are 1.5°C and 25.1°C, respectively.
Site history: Historically, prairie dogs were common throughout the area, but were exterminated by the early 1970’s (John Ford, United States Department of Agriculture Wildlife Services, personal communication). Gunnison’s prairie dogs began to re-colonize the study site from adjacent private land in 1998. During our study, the colony occurred within a 5 ha area, near the base of the Los Piños Mountains in an area with deep clayey loam soils. The site has been long inhabited by kangaroo rats, and represents typical northern Chihuahuan Desert grassland.
North Coordinate:34.406954South Coordinate:34.406954East Coordinate:106.606269West Coordinate:106.606269