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Integrating ecological theory with empirical methods is ubiquitous in ecology using hierarchical Bayesian models. However, there has been little development focused on integration of ecological theory into models for survival analysis. Survival is a fundamental process, linking individual fitness with population dynamics, but incorporating life history strategies to inform survival estimation can be challenging because mortality processes occur at multiple scales. We develop an approach to survival analysis, incorporating model constraints based on a species' life history strategy using functional analytical tools. Specifically, we structurally separate intrinsic patterns of mortality that arise from age‐specific processes (e.g. increasing survival during early life stages due to growth or maturation, versus senescence) from extrinsic mortality patterns that arise over different periods of time (e.g. seasonal temporal shifts). We use shape constrained generalized additive models (CGAMs) to obtain age‐specific hazard functions that incorporate theoretical information based on classical survivorship curves into the age component of the model and capture extrinsic factors in the time component. We compare the performance of our modelling approach to standard survival modelling tools that do not explicitly incorporate species life history strategy in the model structure, using metrics of predictive power, accuracy, efficiency and computation time. We applied these models to two case studies that reflect different functional shapes for the underlying survivorship curves, examining age‐period survival for white‐tailed deer Odocoileus virginianus in Wisconsin, USA and Columbian sharp‐tailed grouse Tympanuchus phasianellus columbianus in Colorado, USA. We found that models that included shape constraints for the age effects in the hazard curves using CGAMs outperformed models that did not include explicit functional constraints. We demonstrate a data‐driven and easily extendable approach to survival analysis by showing its utility to obtain hazard rates and survival probabilities, accounting for heterogeneity across ages and over time, for two very different species. We show how integration of ecological theory using constrained generalized additive models, with empirical statistical methods, enhances survival analyses.

Fragmentation of the sagebrush (Artemisia spp.) ecosystem has led to concern about a variety of sagebrush obligates including the greater sage-grouse (Centrocercus urophasianus). Given the increase of energy development within greater sage-grouse habitats, mapping seasonal habitats in pre-development populations is critical. The North Park population in Colorado is one of the largest and most stable in the state and provides a unique case study for investigating resource selection at a relatively low level of energy development compared to other populations both within and outside the state. We used locations from 117 radio-marked female greater sage-grouse in North Park, Colorado to develop seasonal resource selection models. We then added energy development variables to the base models at both a landscape and local scale to determine if energy variables improved the fit of the seasonal models. The base models for breeding and winter resource selection predicted greater use in large expanses of sagebrush whereas the base summer model predicted greater use along the edge of riparian areas. Energy development variables did not improve the winter or the summer models at either scale of analysis, but distance to oil/gas roads slightly improved model fit at both scales in the breeding season, albeit in opposite ways. At the landscape scale, greater sage-grouse were closer to oil/gas roads whereas they were further from oil/gas roads at the local scale during the breeding season. Although we found limited effects from low level energy development in the breeding season, the scale of analysis can influence the interpretation of effects. The lack of strong effects from energy development may be indicative that energy development at current levels are not impacting greater sage-grouse in North Park. Our baseline seasonal resource selection maps can be used for conservation to help identify ways of minimizing the effects of energy development.

Background Characterizing animal space use is critical for understanding ecological relationships. Animal telemetry technology has revolutionized the fields of ecology and conservation biology by providing high quality spatial data on animal movement. Radio-telemetry with very high frequency (VHF) radio signals continues to be a useful technology because of its low cost, miniaturization, and low battery requirements. Despite a number of statistical developments synthetically integrating animal location estimation and uncertainty with spatial process models using satellite telemetry data, we are unaware of similar developments for azimuthal telemetry data. As such, there are few statistical options to handle these unique data and no synthetic framework for modeling animal location uncertainty and accounting for it in ecological models. We developed a hierarchical modeling framework to provide robust animal location estimates from one or more intersecting or non-intersecting azimuths. We used our azimuthal telemetry model (ATM) to account for azimuthal uncertainty with covariates and propagate location uncertainty into spatial ecological models. We evaluate the ATM with commonly used estimators (Lenth (1981) maximum likelihood and M-Estimators) using simulation. We also provide illustrative empirical examples, demonstrating the impact of ignoring location uncertainty within home range and resource selection analyses. We further use simulation to better understand the relationship among location uncertainty, spatial covariate autocorrelation, and resource selection inference. Results We found the ATM to have good performance in estimating locations and the only model that has appropriate measures of coverage. Ignoring animal location uncertainty when estimating resource selection or home ranges can have pernicious effects on ecological inference. Home range estimates can be overly confident and conservative when ignoring location uncertainty and resource selection coefficients can lead to incorrect inference and over confidence in the magnitude of selection. Furthermore, our simulation study clarified that incorporating location uncertainty helps reduce bias in resource selection coefficients across all levels of covariate spatial autocorrelation. Conclusion The ATM can accommodate one or more azimuths when estimating animal locations, regardless of how they intersect; this ensures that all data collected are used for ecological inference. Our findings and model development have important implications for interpreting historical analyses using this type of data and the future design of radio-telemetry studies.

Chick and juvenile survival are important vital rates for population monitoring and making sound management decisions. These demographics are poorly understood in Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus) and survival estimation in the first 2 weeks is particularly challenging to assess. In 2015–2017, we captured 1,219 chicks (1–7 days old) from 156 broods. We marked 625 chicks with radio-transmitters to monitor their survival and recaptured them to replace the radio-transmitter from 18–30 days old. Overall survival of chicks and juveniles for the brood-rearing season (initial capture–31 Aug) was 0.30 ± 0.02 (SE; 95% CI = 0.26, 0.35, n = 746) using the Kaplan-Meier product-limit estimator. We used Cox proportional hazards regression to model survival and for chicks entering the study at 2–4 days old, survival to 21 days old was 0.59 ± 0.03 (95% CI = 0.53, 0.65, n = 529) and increasing chick mass had a positive effect on chick survival probability, with a 6.0% decrease in mortality risk for each additional gram of mass at initial capture. Juvenile survival was 0.51 ± 0.04 (95% CI = 0.43, 0.60, n = 294) and differed by study site. Of our 4 study sites, the 2 western sites (West Axial, Iles Dome) had 65–80% greater hazard compared to the 2 more eastern sites (Routt, Trapper). Juvenile survival was also influenced by hatch date, with a 3.0% greater hazard for each day later in the nesting season that a nest hatched. Because chick survival is positively influenced by greater mass at capture and juvenile survival was positively affected by earlier hatching dates of broods, management actions should focus on improving the habitat surrounding lek sites to increase the success of initial nests and to provide high quality (increased levels of calcium, phosphorus, and protein) and quantity forage to nesting females and chicks to increase survival and population stability. Additionally, given that lower mass increases the hazard for chick survival, researchers planning to mark chicks should not mark individuals < 11 g when using a 0.55-g radio-transmitter. Radio-transmitters for chicks should not exceed 5.0% of the chicks’ body mass at the time of marking.

Wildlife management and conservation can be challenging when the demography of a focal species is unknown or limited given that fecundity and adult survival influence population growth. The Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus) have been reduced to ≤10% of their former range since the early 1900s. We conducted a 3-year study (2015–2017) across 4 study sites in northwestern Colorado, USA, to evaluate female hazard and nest survival. We trapped and marked 270 female sharp-tailed grouse and identified 275 nests for our hazard and survival analyses. Females during the breeding stage of the reproductive season experienced more hazard compared to the nesting and the early and late post-nesting stages for females without broods. Females experienced a higher degree of hazard during the breeding stage and mortality risk was >3 times higher than the nesting stage, >7 times higher than early post-nesting (EPN)-no brood stage, and >5 times higher than the late post-nesting (LPN)-unsuccessful stage. Two reproductive season stages (LPN-successful and EPN-brood) provided marginal inference. Nest incubation initiation date and nest age best described nest daily survival. Females that initiated incubation of initial nests earlier in the season experienced lower nest daily survival than later in the incubation season. Because female Columbian sharp-tailed grouse hazard varied among different reproductive season stages, we recommend that wildlife managers develop management actions that reduce hazard during the specific reproductive season stages (i.e., the breeding season). For Columbian sharp-tailed grouse in Colorado, we recommend that Colorado Parks and Wildlife collaborate with federal farm program agencies to implement a no-tillage restriction from 1 May through 30 June for active agricultural fields within 2 km of active Columbian sharp-tailed grouse leks to enhance nest survival.

Animal site fidelity structures space use, population demography and ultimately gene flow. Understanding the adaptive selection for site fidelity patterns provides a mechanistic understanding to both spatial and population processes. This can be achieved by linking space use with environmental variability (spatial and temporal) and demographic parameters. However, rarely is the environmental context that drives the selection for site fidelity behaviour fully considered. We use ecological theory to understand whether the spatial and temporal variability in breeding site quality can explain the site fidelity behaviour and demographic patterns of Gunnison sage‐grouse (Centrocercus minimus). We examined female site fidelity patterns across multiple spatial scales: proximity of consecutive year nest locations, space‐use overlap within and across the breeding and brooding seasons, and fidelity to a breeding patch. We also examined the spatial and temporal variability in nest, chick, juvenile and adult survival. We found Gunnison sage‐grouse to be site faithful to their breeding patch, area of use within the patch and generally where they nest, suggesting an “Always Stay” site fidelity strategy. This is an optimal evolutionary strategy when site quality is unpredictable. Further, we found limited spatial variability in survival within age groups, suggesting little demographic benefit to moving among patches. We suggest Gunnison sage‐grouse site fidelity is driven by the unpredictability of predation in a relatively homogeneous environment, the lack of benefits and likely costs to moving across landscape patches and leaving known lek and breeding/brooding areas. Space use and demography are commonly studied separately. More so, site fidelity patterns are rarely framed in the context of ecological theory, beyond questions related to the win‐stay:lose‐switch rule. To move beyond describing patterns and understand the adaptive selection driving species movements and their demographic consequences require integrating movement, demography and environmental variability in a synthetic framework. Site fidelity theory provides a coherent framework to simultaneously investigate the spatial and population ecology of animal populations. Using it to frame ecological questions will lead to a more mechanistic understanding of animal movement, spatial population structuring and meta‐population dynamics. A free Plain Language Summary can be found within the Supporting Information of this article. A free Plain Language Summary can be found within the Supporting Information of this article.

Delineating and prioritizing areas where wildlife occur on a seasonal basis is critical for successful conservation and management of at-risk populations. Many local populations of greater sage-grouse (Centrocercus urophasianus) are of conservation concern in western North America because of continuing habitat loss and degradation caused by changing land use. To manage populations, wildlife managers need accurate, high-resolution maps of different seasonal habitats, guidelines for managing habitat at landscape scales, and quantitative tools to inform habitat prioritization and management. We conducted population-level, multi-scale, resource selection function (RSF) analyses with generalized estimating equations (GEE) using locations from 2006 to 2010 to model and map greater sage-grouse seasonal habitats in the Parachute-Piceance-Roan population in northwestern Colorado. Areas selected by greater sage-grouse in all seasons had a mix of habitats with a sagebrush component, less rugged topography, and less non-sagebrush habitat. Selection or avoidance of most vegetation classes was best supported at the 100-m or 400-m scale in all seasons. Birds selected sagebrush and sagebrush-grassland at intermediate elevations during breeding and winter and more diverse sagebrush habitats at higher elevations in summer and fall. Absolute validation index (AVI) analyses indicated that although most use locations were concentrated within a highly restricted portion of the study area in each season, a much larger proportion of the study area was required to encompass seasonal use locations for most individuals in the population. Our study illustrates the utility of multi-scale RSF analyses with GEE for accurately mapping habitat and AVI analyses for informing prioritization efforts for populations of greater sage-grouse.

Juvenile survival and recruitment has not been studied extensively for greater sage-grouse (Centrocercus urophasianus). Because there is scant information on this vital rate, the implications of management actions on specific population demographics remain unknown. We re-captured, radio-marked, and monitored the survival and recruitment of 183 domestically hatched and wild-hatched juvenile sage-grouse from 1 September to 31 March 2005–2008 at 2 study areas in northwest Colorado, USA: Axial Basin and Cold Springs Mountain. Juvenile females had higher survival than juvenile males, and survival for each was higher in Axial Basin compared to Cold Springs Mountain. Domestically hatched juveniles had comparable survival to wild-hatched juveniles. We documented differences in survival between adult females and juveniles from September to March. Juvenile survival was lowest during September and October, coinciding with brood independence and movements to winter range and integrated flocks. Average survival from hatch to recruitment into the natal breeding population (Mar) varied between areas. Our findings provide an estimate of juvenile survival and recruitment so managers can better understand and model sage-grouse population dynamics. We recommend long-term (≥3 yr) research to better understand spatial and temporal variation in demographic rates.

Maintenance of genetic diversity is important for conserving species, especially those with fragmented habitats or ranges. In the absence of natural dispersal, translocation can be used to achieve this goal, although the success of translocation can be difficult to measure. Here we evaluate genetic change following translocation in Gunnison Sage-Grouse (Centrocercus minimus), a species reduced to 7 discrete populations with low levels of gene flow and high levels of genetic differentiation. Between 2000 and 2014, 306 birds from the largest and most genetically diverse population (Gunnison Basin) were translocated to 5 much smaller satellite populations to augment local population size and increase genetic diversity. Although the magnitude of the effect varied by population, we found evidence of increased genetic variation, decreased genetic differentiation from Gunnison Basin, and reproduction between translocated individuals and resident birds. These results suggest that translocations are impacting satellite populations, with current data providing a new baseline for genetic diversity among populations of this imperiled species.

Fragmentation of the sagebrush (Artemisia spp.) ecosystem has led to concern about a variety of sagebrush obligates including the greater sage-grouse (Centrocercus urophasianus). Given the increase of energy development within greater sage-grouse habitats, mapping seasonal habitats in pre-development populations is critical. The North Park population in Colorado is one of the largest and most stable in the state and provides a unique case study for investigating resource selection at a relatively low level of energy development compared to other populations both within and outside the state. We used locations from 117 radio-marked female greater sage-grouse in North Park, Colorado to develop seasonal resource selection models. We then added energy development variables to the base models at both a landscape and local scale to determine if energy variables improved the fit of the seasonal models. The base models for breeding and winter resource selection predicted greater use in large expanses of sagebrush whereas the base summer model predicted greater use along the edge of riparian areas. Energy development variables did not improve the winter or the summer models at either scale of analysis, but distance to oil/gas roads slightly improved model fit at both scales in the breeding season, albeit in opposite ways. At the landscape scale, greater sage-grouse were closer to oil/gas roads whereas they were further from oil/gas roads at the local scale during the breeding season. Although we found limited effects from low level energy development in the breeding season, the scale of analysis can influence the interpretation of effects. The lack of strong effects from energy development may be indicative that energy development at current levels are not impacting greater sage-grouse in North Park. Our baseline seasonal resource selection maps can be used for conservation to help identify ways of minimizing the effects of energy development.