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The Sage Grouse Centrocercus urophasianus is a species of conservation concern throughout its range in western North America. Since the 1950s, the high count of males at leks has been used as an index for monitoring populations. However, the relationship between this lek‐count index and population size is unclear, and its reliability for assessing population trends has been questioned. We used non‐invasive genetic mark‐recapture analysis of faecal and feather samples to estimate pre‐breeding population size for the Parachute‐Piceance‐Roan, a small, geographically isolated population of Sage Grouse in western Colorado, during two consecutive winters from 2012 to 2014. We estimated total pre‐breeding population size as 335 (95% confidence interval (CI): 287–382) in the first winter and 745 (95% CI: 627–864) in the second, an approximate doubling in abundance between years. Although we also observed a large increase in the spring lek‐count index between those years, high male count data poorly represented mark‐recapture estimates of male abundance in each year. Our data suggest that lek counts are useful for detecting the direction and magnitude of large changes in Sage Grouse abundance over time but they may not reliably reflect small changes in abundance that may be relevant to small populations of conservation concern. [ABSTRACT FROM AUTHOR]

Effective monitoring programs are important for ensuring proper management of wildlife populations, but they require substantial resources, effort, and funding. For this reason, managers often use indices of animal abundance. However, indices typically rely on untested assumptions and may be unreliable for estimating population size, status, and trend. Therefore, it is important to test the assumptions underlying indices and to evaluate more rigorous methods of population estimation. Counts of males at leks are used as an index to monitor populations of greater sage‐grouse (Centrocercus urophasianus), a species of conservation concern, throughout its range in the western United States and Canada. However, not all leks are known, and wildlife managers typically have no rigorous, quantitative estimates of the number of leks and males in any given population. Therefore, it remains unclear what proportion of leks and males are included in, or excluded from, lek‐based population status assessments, trend analyses, and management decisions. We used dual‐frame surveys, in combination with occupancy analysis to adjust for imperfect detection, to estimate the number of active leks, the number of lekking males, and the proportion of active leks and lekking males counted on annual lek surveys over 3 consecutive breeding seasons in a small, low‐density greater sage‐grouse population in northwestern Colorado, USA. We estimated that annual lek surveys captured an average of 45–74% of active leks and 43–78% of lekking males each year. Our results suggest that many active leks remain unknown and annual counts fail to account for a substantial, but variable, proportion of the number of active leks and lekking males in the population in any given year. Managers need to recognize this potential source of bias in lek‐count data and, if possible, account for it in trend analyses and management efforts. Increased cost likely precludes annual use of dual‐frame lek surveys. However, we recommend using analytical methods that account for imperfect detection, mapping potential lek habitat to improve survey efficiency, and conducting dual‐frame surveys over multiple years to better understand temporal variation in the proportion of active greater sage‐grouse leks and lekking males being counted in specific populations of interest. © 2018 The Wildlife Society. We used dual‐frame surveys to estimate the number of active leks, lekking males, and the proportion of active leks and males counted during annual lek surveys in a small, low‐density greater sage‐grouse population in northwestern Colorado. We found that many active leks likely remained unknown and recommend managers use dual‐frame surveys to determine the proportion of active leks that are being surveyed in any given population. [ABSTRACT FROM AUTHOR]

Habitat fragmentation and the associated reduction in connectivity between habitat patches are commonly cited causes of genetic differentiation and reduced genetic variation in animal populations. We used eight microsatellite markers to investigate genetic structure and levels of genetic diversity in a relict population of wood frogs ( Lithobates sylvatica) in Rocky Mountain National Park, Colorado, where recent disturbances have altered hydrologic processes and fragmented amphibian habitat. We also estimated migration rates among subpopulations, tested for a pattern of isolation-by-distance, and looked for evidence of a recent population bottleneck. The results from the clustering algorithm in Program STRUCTURE indicated the population is partitioned into two genetic clusters (subpopulations), and this result was further supported by factorial component analysis. In addition, an estimate of F ( F = 0.0675, P value <0.0001) supported the genetic differentiation of the two clusters. Estimates of migration rates among the two subpopulations were low, as were estimates of genetic variability. Conservation of the population of wood frogs may be improved by increasing the spatial distribution of the population and improving gene flow between the subpopulations. Construction or restoration of wetlands in the landscape between the clusters has the potential to address each of these objectives. [ABSTRACT FROM AUTHOR]

The article reports that two populations of boreal toads have experienced radical declines in the late 1990s. Evidence supports the hypothesis of disease as the cause of these declines. The chytrid fungus and batrachochytrium dendrobatidis are mainly responsible for this decline. The populations of boreal toads at Kettle Tarn (KT) and Lost Lake (LL) in Rocky Mountain National Park, Colorado, USA have experienced recent declines and appear to be approaching extinction. The populations at KT and LL have been sampled annually, using capture-recapture methods. These data offer an opportunity to assess the temporal and spatial variability in the demographic parameters of declining amphibian populations. Although there was no evidence to suggest that weather conditions at KT and LL were responsible for the decline, an analysis of the data provided evidence that temporal variation in the survival rates of boreal toads is positively correlated with winter air temperature and the length of the previous growing season.