Private lands in the American West are undergoing a land‐use conversion from agriculture to exurban development, although little is known about the ecological consequences of this change. Some nongovernmental organizations are working with ranchers to keep their lands out of development and in ranching, ostensibly because they believe biodiversity is better protected on ranches than on exurban developments. However, there are several assumptions underlying this approach that have not been tested. To better inform conservation efforts, we compared avian, mesopredator, and plant communities across the gradient of intensifying human uses from nature reserves to cattle ranches to exurban developments. We conducted surveys at randomly selected points on each type of land use in one Colorado watershed between May and August of 2000 and 2001. Seven bird species, characterized as human commensals or tree nesters, reached higher densities ( all p < 0.02 ) on exurban developments than on either ranches or reserves. Six bird species, characterized as ground and shrub nesters, reached greater densities ( all p < 0.015 ) on ranches, reserves, or both of these types of land use than on exurban developments. Domestic dogs ( Canis familiaris ) and house cats (  Felis catus ) were encountered almost exclusively on exurban developments, whereas coyotes ( Canis latrans ) were detected more frequently ( p = 0.047 ) on ranchlands than exurban developments. Ranches had plant communities with higher native species richness and lower non‐native species richness and cover than did the other types of land use ( all p < 0.10 ). Our results support the notion that ranches are important for protecting biodiversity and suggest that future conservation efforts may require less reliance on reserves and a greater focus on private lands.

Traditionally, exurban lands in Colorado have been subdivided into a grid of parcels ranging from 2 to 16 ha. From an ecological perspective, this dispersed pattern of development effectively maximizes the individual influence of each home on the land. Clustered housing developments, designed to maximize open space, are assumed to benefit plant and wildlife communities of conservation interest. They have become a popular alternative for rural development despite the lack of empirical evidence demonstrating their conservation benefits. To better inform rural land-use planning, we evaluated clustered housing developments by comparing their spatial pattern with that of dispersed housing developments and by comparing their conservation value with that of both dispersed housing developments and undeveloped areas in Boulder County, Colorado. We used four indicators to assess conservation value: (1) densities of songbirds, (2) nest density and survival of ground-nesting birds, (3) presence of mammals, and (4) percent cover and proportion of native and non-native plant species. Clustered and dispersed housing developments did not differ on the majority of variables we examined. Both types of housing development had significantly higher densities of non-native and human-commensal species and significantly lower densities of native and human-sensitive species than undeveloped areas. More rigorous ecological guidelines and planning on a regional scale may help create clustered developments with higher conservation value.

We evaluated the effect of habitat use and other sources of variation on survival of lesser prairie‐chicken (Tympanuchus pallidicinctus) and greater prairie‐chicken (Tympanuchus cupido) nests and broods. Daily nest and brood‐survival probabilities were a function of a quadratic time trend, and both declined as the season progressed. Daily nest survival was negatively associated with nest age, and daily brood survival was positively associated with brood age. Lastly, broods tended by adult females had higher daily survival rates than broods reared by subadult females. The probability of a nest surviving from 10 May to 1 June was 0.72 (SE = 0.06). The probability of a brood surviving from 1 June to 30 July (hatch to 60 days posthatch) was 0.49 (SE = 0.19) and 0.05 (SE = 0.03) for broods reared by adults and subadults, respectively. Although nesting females and females with broods were using Conservation Reserve Program grasslands, there appeared to be no benefit to nest and brood survival during our study. Instead, age of the nest and brood, timing during the season, age of the brooding female, and precipitation during brooding were more important predictors of survival. Further experimentation is needed to determine the mechanisms responsible for decreased nest and brood survival throughout the season. Results from such research could be used to formulate management strategies to improve nest and brood survival.