The Restoration of Elk (Cervus elaphus) in Ontario, Canada: 1998–2005

In 1997, a plan to restore Elk (Cervus elaphus) to Ontario was approved by the provincial government. The objective of the Ontario elk restoration program, a multipartnered collaboration, was to restore a species that had been extirpated from the province during the 1800s. During 1998–2001, 460 elk were acquired from Elk Island National Park, Alberta, for release in four areas of Ontario. As greater than 90% of the elk were radio collared, monitoring provided detailed information on the dynamics of the four populations. Comprehensive research projects using graduate students were implemented to determine the environmental impact of releasing elk in Ontario. Those studies are in progress or have been completed and include the effect of wolf predation on restored elk, white‐tailed deer and elk resource overlap, the development of genetic profiles for elk, and solutions for elk/human conflicts. Mortality of the released elk averaged 41% (190/460) during 1998–2004 with annual mortality generally declining over time in each release area. The primary causes of elk mortality included wolf predation (25% of mortalities), illegal shooting (13%), stress‐related emaciation (13%) (partially due to the stress of relocation), bacterial infections (7%), and collisions with vehicles (6%). Productivity has been high in one of the release areas with 24–65% of the cows being observed with calves during late winter surveys. However, productivity has been low in two of the northern release areas due to a variety of factors including wolf predation. In some areas, dispersion of elk appeared to be related to the length of time animals were kept in pens prior to release. The precalving population estimate for Ontario in March 2004 was 375–440 elk. A comprehensive program review was conducted in 2003/2004 that included recommendations relating to the future management of elk in Ontario.     

Development of a Sightability Model for Low-Density Elk Populations in Ontario,Canada

ABSTRACT The status of recolonizing elk (Cervus elaphus) populations in Ontario, Canada, is unclear and there is a need for effective population survey methods that can be applied locally. We sought to develop a sightability model that could account for both low densities of elk and dense forest cover in elk-release areas in Ontario. We corrected winter aerial survey counts for sightability based on radiocollared animals known to be within observable distance of the aircraft. The multivariate model with the highest Akaike's Information Criterion corrected for sample size weight (w_i = 0.427) revealed that elk group size, elk activity, dominant tree type, percent canopy cover, and percent conifer cover were significant predictors of elk sightability. The group-size effect indicated that odds of sighting an elk increased by 1.353 (95% CI = 0.874-3.689) for every additional elk. Standing elk were 5.033 (95% CI = 0.936-15.541) times more likely to be observed than were resting elk, and those located in conifer cover were 0.013 (95% CI = 0.001-0.278) times less likely to be sighted than elk in deciduous cover. Furthermore, elk located in >50% canopy cover and >50% conifer cover were 0.041 (95% CI = 0.003-0.619) times and 0.484 (95% CI = 0.024-9.721) times less likely to be sighted than elk in more open habitat, respectively. During model validation, observers detected 79% (113/143) of known elk in any given area, and population and sightability model predictions (±90% CI) overlapped with the population estimate, implying that our predictive model was robust. Unsurprisingly, large groups of elk in open habitat increased model precision, which highlights difficulties of counting Ontario elk in their northern range. We conclude that our model provided increased reliability for estimating elk numbers in Ontario compared to existing methods, and that the estimator may be useful in other areas where elk density is low and sightability is poor due to dense forest cover.     

Influence of Predator Harvest,Biological Factors,and Landscape on Elk Calf Survival in Idaho

ABSTRACT We evaluated survival of elk (Cervus elaphus) calves on 2 contrasting study areas in north-central Idaho, USA, from 1997 to 2004. Recruitment was modest (>30 calves:100 F [calves of either sex: F elk 1 yr old]) and stable on the South Fork study area and low (<20 calves:100 F) and declining on the Lochsa study area. The primary proximate cause of calf mortality on both study areas was predation by black bears (Ursus americanus) and mountain lions (Puma concolor). We experimentally manipulated populations of black bears and mountain lions on a portion of each study area. Black bear harvest (harvest density/600km²) initially doubled on the Lochsa treatment after manipulating season bag limits. Mountain lion harvest also increased by 60% but varied widely during the manipulation period. Harvest seasons were closed for black bears and mountain lions on the treatment portion of the South Fork study area. Using the Andersen—Gill formulation (A-G) of the Cox proportional hazards model, we examined effects of landscape structure, predator harvest levels, and biological factors on summer calf survival. We used Akaike's Information Criterion (AIC_c) and multimodel inference to assess some potentially useful predictive factors relative to calf survival. We generated risk ratios for both the best models and for model-averaged coefficients. Our models predicted that calf survival was influenced by biological factors, landscape surrounding calf locations, and predator harvest levels. The model that best explained mortality risk to calves on the Lochsa included black bear harvest (harvest density/600 km²), estimated birth mass of calves, and percentage of shrub cover surrounding calf locations. Incorporating a shrub X time interaction allowed us to correct for nonproportionality and detect that effect of shrub cover was only influential during the first 14 days of a calf's life. Model-averaging indicated that estimated birth mass of calves and black bear harvest were twice as important as the next variables, but age of calves at capture was also influential in calf survival. The model that best explained mortality risk to calves on the South Fork included black bear harvest, age of calves at capture, and gender of calves. Model-averaging indicated that age at capture and black bear harvest were twice as important as the next variable, forest with 33–66% canopy cover (Canopy 33–66). Risk to calves decreased when calves occupied areas with more of this forest cover type. Model-averaging also indicated that increased mountain lion harvest lowered calf mortality risk 4% for every 1-unit increase in lion harvest (harvest density/600 km²) but was lower (<25%) in importance compared to age at capture and black bear harvest. Our results suggest that levels of predator harvest, and presumably predator density, resource limitations expressed through calf birth mass, and habitat structure had substantial effects on calf survival. Our results can be generalized to other areas where managers are dealing with low calf elk recruitment. However, because factors vary spatially, a single management strategy applied in different areas will probably not have the same effect on calf survival.     

Postrelease Dispersal of Reintroduced Elk (Cervus elaphus) in Ontario,Canada

We studied 2 years of postrelease telemetry data of elk (Cervus elaphus) translocated to their historic range limit in Ontario, Canada and sought to determine if postrelease movements were related to behavior, demography of released animals, or site–specific attributes such as length of holding period. During 1998–2004 we radio‐tracked 341 elk in 10 release groups via ground and aerial telemetry and monitored movement patterns relative to gender, age, and pre‐release holding period (4–112 days). We found that elk that were held for short periods prior to release (4–11 days) moved longer distances than those subject to extended conditioning (17–112 days), suggesting that an extended conditioning period is beneficial from the standpoint of promoting philopatry. When all elk were pooled by sex and age class, male calves remained in closer proximity (8.0 ± 13.2 km) to release sites than adult females (19.1 ± 20.6 km), adult males (19.7 ± 15.1 km), and female calves (14.4 ± 20.4 km). Most calves dispersed in a southeasterly direction whereas adults tended to travel southwest. Our results reveal that elk movement characteristics are influenced by factors such as release protocol and group demographics; these findings provide further insight regarding appropriate release methods for restoring natural populations near their historical range limit.     

Elk survival and mortality causes in the Blue Mountains of Washington

We studied survival of elk (Cervus elaphus) ≥1 yr old and quantified mortality sources in the Blue Mountains of Washington, 2003–2006, following a period of extensive poaching. The population was managed under a spike-only general hunting season, with limited permits for larger males and for females. We radiomarked 190 elk (82 males and 39 females >1 yr old and 65 males 11 months old), most with rumen transmitters and neck radiocollars; 60 elk only received rumen transmitters. We estimated annual survival using known fate models and explored survival differences among sex and age classes and in 2 potentially different vulnerability zones for males. We found little support for differences in survival between younger (2–3-yr old) and older (≥4-yr old) branch-antlered males or zone differences for yearling males. A model with zone differences for branch-antlered males was the second ranked model and accounted for 14% of the available model weight. From the best-supported models, we estimated annual survival for yearling males at 0.41 (95% CI: 0.29–0.53). We estimated pooled adult female survival at 0.80 (95% CI: 0.64–0.93); when an age-class effect was included, point estimates were higher for prime-aged females (2–11 yr: S = 0.81 [0.70–0.88]) than for older females (≥12 yr: S = 0.72 [0.56–0.83]), but confidence intervals broadly overlapped. Only 1 of 7 models with a female age effect on survival was among the competitive models. For branch-antlered males, survival ranged 0.80–0.85, depending on whether zone variation was modeled. We recorded 78 deaths of radiomarked elk. Human-caused deaths (n = 55) predominated among causes and most were of yearling males killed during state-sanctioned hunts (n = 28). Most subadult male deaths were from tribal hunting (n = 5), and most mature males died from natural causes (n = 6) and tribal hunting (n = 5). We detected few illegal kills (n = 4). Our results suggest that increased enforcement effectively reduced poaching, that unreported tribal harvest was not a trivial source of mortality, and that spike-only general seasons were effective in recruiting branch-antlered males. © 2011 The Wildlife Society.     

Demographics of an Experimentally Released Population of Elk in Great Smoky Mountains National Park

ABSTRACT We assessed the potential for reestablishing elk (Cervus elaphus) in Great Smoky Mountains National Park (GSMNP), USA, by estimating vital rates of experimentally released animals from 2001 to 2006. Annual survival rates for calves ranged from 0.333 to 1.0 and averaged 0.592. Annual survival for subadult and adult elk (i.e., ≥ 1 yr of age) ranged from 0.690 to 0.933, depending on age and sex. We used those and other vital rates to model projected population growth and viability using a stochastic individual-based model. The annual growth rate (λ) of the modeled population over a 25-year period averaged 0.996 and declined from 1.059 the first year to 0.990 at year 25. The modeled population failed to attain a positive 25-year mean growth rate in 46.0% of the projections. Poor calf recruitment was an important determinant of low population growth. Predation by black bears (Ursus americanus) was the dominant calf mortality factor. Most of the variance of growth projections was due to demographic variation resulting from the small population size (n = 61). Management actions such as predator control may help increase calf recruitment, but our projections suggest that the GSMNP elk population may be at risk for some time because of high demographic variation.     

Genetic Characteristics of Restored Elk Populations in Kentucky

Translocations are a common management practice to restore or augment populations. Understanding the genetic consequences of translocation efforts is important for the long-term health of restored populations. The restoration of elk (Cervus canadensis) to Kentucky, USA, included source stocks from 6 western states, which were released at 8 sites in southeastern Kentucky during 1997–2002. We assessed genetic diversity in restored herds and compared genetic similarity to source stocks based on 15 microsatellite DNA loci. Genetic variation in the restored populations was comparable to source stocks ( allelic richness = 3.52 and 3.50; expected heterozygosity = 0.665 and 0.661 for restored and source, respectively). Genetic differentiation among all source and restored populations ranged from 0.000 to 0.065 for pairwise F_ST and 0.034 to 0.161 for pairwise Nei's D_A. Pairwise genetic differentiation and Bayesian clustering revealed that stocks from Utah and North Dakota, USA, contributed most to restored populations. Other western stocks appeared less successful and were not detected with our data, though our sampling was not exhaustive. We also inferred natural movements of elk among release sites by the presence of multiple genetic stocks. The success of the elk restoration effort in Kentucky may be due, in part, to the large number of elk (n = 1,548), repeated releases, and use of diverse source stocks. Future restoration efforts for elk in the eastern United States should consider the use of multiple stock sources and a large number of individuals. In addition, preservation of genetic samples of founder stock will enable detailed monitoring in the future. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

Constant Proportionality in the Female Segment of a Roosevelt Elk Population

Abstract: Incomplete population counts indicate change in population sizes when constant proportionality holds, a condition that is rarely met. However, researchers have not explored whether constant proportionality holds for a segment of a population. I examined whether the female segment (juv, subadult M, subadult and ad F) of a Roosevelt elk (Cervus elaphus roosevelti) population displayed constant proportionality. When most food is in particular habitats, females of polygynous species should use that habitat frequently, even when food is limited, because they are more familiar with food distribution and abundance than males. I obtained counts of elk and tallies of naturally marked animals from vehicle surveys of a population inhabiting a landscape where forage was in meadows that were interspersed in closed-canopied forest. I conducted population surveys in January or February and estimated population size with Bowden's mark-resight estimator. Population size estimates declined from 130 in 1997 to 37 in 2006. The proportion of the population counted during surveys was inversely related to population size estimates. Estimated population sizes were inversely related to male (r² = 0.56) but not female sighting probabilities (r² = 0.004), which were ≥0.9. Constant proportionality in counts held for only the female segment of the population. Counts of the female segment of the population can inform managers about changes in this segment of the population over time.     

Identifying Sites for Elk Restoration in Arkansas

Abstract: We used spatial data to identify potential areas for elk (Cervus elaphus) restoration in Arkansas. To assess habitat, we used locations of 239 elk groups collected from helicopter surveys in the Buffalo National River area of northwestern Arkansas, USA, from 1992 to 2002. We calculated the Mahalanobis distance (D²) statistic based on the relationship between those elk-group locations and a suite of 9 landscape variables to evaluate winter habitat in Arkansas. We tested model performance in the Buffalo National River area by comparing the D² values of pixels representing areas with and without elk pellets along 19 fixed-width transects surveyed in March 2002. Pixels with elk scat had lower D² values than pixels in which we found no pellets (logistic regression: Wald χ² = 24.37, P < 0.001), indicating that habitat characteristics were similar to those selected by the aerially surveyed elk. Our D² model indicated that the best elk habitat primarily occurred in northern and western Arkansas and was associated with areas of high landscape heterogeneity, heavy forest cover, gently sloping ridge tops and valleys, low human population density, and low road densities. To assess the potential for elk-human conflicts in Arkansas, we used the analytical hierarchy process to rank the importance of 8 criteria based on expert opinion from biologists involved in elk management. The biologists ranked availability of forage on public lands as having the strongest influence on the potential for elk-human conflict (33%), followed by human population growth rate (22%) and the amount of private land in row crops (18%). We then applied those rankings in a weighted linear summation to map the relative potential for elk-human conflict. Finally, we used white-tailed deer (Odocoileus virginianus) densities to identify areas where success of elk restoration may be hampered due to meningeal worm (Parelaphostrongylus tenuis) transmission. By combining results of the 3 spatial data layers (i.e., habitat model, elk-human conflict model, deer density), our model indicated that restoration sites located in west-central and north-central Arkansas were most favorable for reintroduction.     

Population viability analysis to identify management priorities for reintroduced Elk in the Cumberland Mountains,Tennessee

We used an individual-based population model to perform a viability analysis to simulate population growth (λ) of 167 elk (Cervus elaphus manitobensis; 71 male and 96 female) released in the Cumberland Mountains, Tennessee, to estimate sustainability (i.e., λ > 1.0) and identify the most appropriate options for managing elk restoration. We transported elk from Elk Island National Park, Alberta, Canada, and from Land Between the Lakes, Kentucky, and reintroduced them beginning in December 2000 and ending in February 2003. We estimated annual survival rates for 156 radio-collared elk from December 2000 until November 2004. We used data from a nearby elk herd in Great Smoky Mountains National Park to simulate pessimistic and optimistic recruitment and performed population viability analyses to evaluate sustainability over a 25-year period. Annual survival averaged 0.799 (Total SE = 0.023). The primary identifiable sources of mortality were poaching, disease from meningeal worm (Parelaphostrongylus tenuis), and accidents (environmental causes and unintentional harvest). Population growth given pessimistic recruitment rates averaged 0.895 over 25 years (0.955 in year 1 to 0.880 in year 25); population growth was not sustainable in 100% of the runs. With the most optimistic estimates of recruitment, mean λ increased to 0.967 (1.038 in year 1 to 0.956 in year 25) with 99.6% of the runs failing to be sustainable. We suggest that further translocation efforts to increase herd size will be ineffective unless survival rates are increased in the Cumberland Mountains. © 2011 The Wildlife Society.     

A Review of Environmental Factors Affecting Elk Winter Diets

Abstract: Decades of research have produced substantial data on elk (Cervus elaphus) diets in winter, when foraging conditions are most likely to affect population dynamics. Using data from 72 studies conducted in western North America between 1938 and 2002, we collated data on elk diets and environmental variables. We used these data to quantify diet selection by elk and to test whether variation in elk diets is associated with habitat type, winter severity, period of winter, human hunting, and study method. Graminoids (grasses and grass-like plants such as sedges) dominated elk diets and consistently occurred at a higher proportion in the diet than in elk foraging habitats, indicating preference. Forbs commonly made up ≤5% of the diet, with no evidence for preference; we conclude that forb use is largely incidental to grazing for graminoids. Browse was consumed in proportion to its availability, implying that the amount of browse in the diet was primarily determined by habitat use rather than selection. Comparing the diets of elk and sympatric ruminants, elk consistently selected graminoids more strongly than sympatric ruminants with the exception of bison (Bison bison), suggesting that elk are not environmentally forced to adopt the graminoid-biased diet that they normally select. The proportion of open meadows and grasslands on winter ranges was strongly and positively associated with graminoid consumption by elk. The proportion of graminoids in the diet was significantly lower in elk experiencing severe winter conditions or predation risk from human hunting. The period of winter (early, middle, and late) had only small effects on elk diets, as did the method by which the diet was determined. Overall, variation in elk diets is well-explained by a consistent tendency to select graminoids if available, modified by winter habitat type, predation risk, and winter severity, which can constrain habitat selection and access to grazing opportunities. To fully understand variation in foraging behavior, biologists should recognize these broad patterns when interpreting resource selection data. Managers should recognize that inconspicuous behavioral responses to environmental stimuli can alter the diet in ways that probably carry nutritional consequences.     

How Size and Condition Influence Survival and Cause-Specific Mortality of Female Elk

The size of animal populations fluctuates with number of births, rate of immigration, rate of emigration, and number of deaths. For many ungulate populations, adult female survival is the most important factor influencing population growth. Therefore, increased understanding of survival and causes of mortality for adult females is fundamental for conservation and management. The objectives of our study were to quantify survival rates of female elk (Cervus canadensis) and determine cause-specific mortality. We predicted that hunter harvest would be the leading cause of mortality. Further, we predicted that hunters would harvest animals that were in prime age (2–9 yr) and in better condition than elk predated by mountain lions (Puma concolor). From 2015 to 2017, we captured 376 female elk in central Utah, USA. We assessed body size and condition of captured elk, fitted each animal with a global positioning system-collar, and determined cause of death when we received mortality signals. We estimated survival using Kaplan-Meier estimates and Cox proportional hazard models within an Akaike's Information Criterion model selection framework to identify covariates that influenced survival. We analyzed differences in size and condition measurements between harvested elk and predated elk using analysis of variance tests. Our best model indicated consistent survival across years; mean survival was 78.3 ± 3.5% (SE) including hunter harvest and 95.5 ± 1.7% without hunter harvest. In decreasing order of importance, elk mortality occurred from hunter harvest (21.2%), mountain lion predation (3.7%), depredation removal (0.5%), automobile collision (0.3%), disease (0.3%), complications during calving (0.3%), and those characterized as undetermined (1.3%). Neck circumference and body length were negatively associated with survival, suggesting that larger animals in good condition had lower survival as a result of hunter harvest. Individuals that died because of cougar predation were smaller and had less loin muscle than the average animal. Hunters removed large, healthy, prime-aged females, individuals that likely have a greater effect on population growth than elk lost to other predators. If the proportion of larger, healthy females in the population begins to decline, hunting practices may require adjustment because hunters may be removing individuals with the greatest reproductive value. © 2021 The Wildlife Society.     

Influences on Release-Site Fidelity of Translocated Elk

Several eastern states are considering the restoration of free‐ranging elk populations via translocation from western populations. Optimal habitat immediately surrounding release sites has been found to enhance elk reintroduction success in western states. Little information exists, however, to aid eastern managers in identifying release sites with the highest chance of restoration success. We monitored the movements of 415 translocated elk released at three sites in southeastern Kentucky to identify landscape characteristics that enhance release‐site fidelity. The distance elk moved after release differed among sites (F_2,322 = 4.63, p = 0.01), age classes (F_2,322 = 4.37, p = 0.01), and time intervals (F_2,322 = 40.74, p < 0.001). At 6 and 12 months post‐release, adults (15.81 ± 17.32 and 16.38 ± 20.29) and yearlings (13.91 ± 16.44 and 14.61 ± 21.11) moved farther than calves (8.06 ± 14.03 and 9.37 ± 14.40). The release site with the highest fidelity was privately owned, 15% open, and had the highest amount of edge compared with the other release sites. The two remaining sites contained large amounts of expansive openland or forest cover with lower amounts of edge. Additionally, both sites were publicly owned and experienced a higher degree of human‐generated disturbance compared with the site to which elk were most faithful. When selecting release sites, managers should avoid areas dominated by a single cover type with little interspersion of other habitats. Rather, areas with high levels of open‐forest edge (approximately 5.0 km/km²) and limited‐human disturbance will likely enhance release‐site fidelity and promote restoration success.     

A Century of Elk Restoration in Eastern North America

Over a century has passed since elk were extirpated in eastern North America. During that time, numerous attempts to reintroduce elk into eastern North America have resulted in varying degrees of success and failure. An overview of restoration efforts during the last 100 years is presented here with emphasis on the differences in rates of population change among regions and differences in major causes of elk mortality during both the pre‐ and post‐acclimation periods. Approximately 40% of recorded elk reintroduction attempts in eastern North America resulted in failure, with the majority of these having occurred in the first half of the 20th century. Although rates of population change in elk were highly variable, they were not related to founding population size. Major causes of mortality varied among regions and should be considered in future reintroduction attempts.     

Impact of Spatial and Temporal Variation in Calf Survival on the Growth of Elk Populations

Abstract: The realized impact of a vital rate on population growth (λ) is determined by both the relative influence of the vital rate on λ (elasticity) and its magnitude of variability. We estimated mean survival and reproductive rates in elk (Cervus elaphus) and spatial and temporal variation in these rates from 37 sources located primarily across the Rocky Mountain region and northwestern United States. We removed sampling variance from estimates of process variance both within and across vital-rate data sets using the variance discounting method developed by White (2000). Deterministic elasticities calculated from a population matrix model parameterized with these mean vital rates ranked adult female survival (e_Scow = 0.869) much higher than calf survival (e_Scalf = 0.131). However, process variance in calf survival was >11 times greater than process variance in female survival across data sets and 10 times greater on average within studies. We conducted Life-Stage Simulation Analysis to incorporate both vital-rate elasticity patterns and empirical estimates of variability to identify those vital rates most influential in elk population dynamics. The overwhelming magnitude of variation in calf survival explained 75% of the variation in the population growth rates generated from 1,000 matrix replicates, compared to just 16% of the variation in λ explained by variation in female survival. Variation in calf survival greatly impacts elk population growth and calls into question the utility of classical elasticity analysis alone for guiding elk management. These results also suggest that the majority of interannual variability that wildlife managers document in late-winter and spring elk surveys is attributable to variation in calf survival over the previous year and less influenced by variation in the harvest of females during the preceding autumn. To meet elk population size objectives, managers should consider the inherent variation in calf survival, and its apparent sensitivity to management, in addition to female harvest.     

Changes in Elk Resource Selection and Distributions Associated With a Late-Season Elk Hunt

ABSTRACT Changes in resource selection associated with human predation risk may alter elk distributions and availability for harvest. We used Global Positioning System data collected from telemetered female elk (Cervus elaphus) to evaluate effects of refuges (areas where hunting was prohibited), spatial variation in hunting risk, and landscape attributes on resource selection within an established Greater Yellowstone Area, USA, winter range. We also evaluated elk distributions during and outside of a late-season hunting period. Refuge areas and landscape attributes such as habitat type and snow water equivalents (SWE) affected resource selection. Elk selection for flat grasslands increased as SWE increased, likely because these areas were windswept, leaving grasses exposed for foraging. Elk distributions differed during hunting and no-hunting periods. During the hunting period, elk shifted to privately owned refuge areas and the estimated odds of elk occupying refuge areas more than doubled. Risk-driven changes in resource selection resulted in reduced availability of elk for harvest. Elk selection for areas where hunting is prohibited presents a challenge for resource managers that use hunting as a tool for managing populations and influences grazing patterns on private ranchlands.     

Using Resource Selection Functions to Improve Estimation of Elk Population Numbers

Abstract: Stratification is commonly used to improve sampling efficiency of aerial surveys of ungulate populations with strata typically based on a priori information, such as preflight animal observations or vegetation attributes as surrogates for animal densities. We evaluated the usefulness of stratifying survey units for elk (Cervus elaphus) in the Rocky Mountain foothills of Alberta, Canada, using a resource selection function (RSF). We compared precision and design efficiency (DEFF) of population estimates from stratification approaches based on an RSF model to the past approach using amount of forest cover. We used a sample of telemetry relocations taken over a 3-year period from 165 elk, rarified to times of the day and months of the year when aerial surveys are conducted, to develop the RSF. We then used the top RSF model, based on Akaike's Information Criterion, to derive the average RSF value for an 8-km² survey unit. Using survey data from the first year, we evaluated binning schemes to define RSF-oriented strata based on poststratification and showed that Jenks natural breaks in the RSF values provided the greatest improvement in DEFF and increased precision, compared to 2 other stratification schemes. We then used this approach with data from 2 additional surveys to find that stratification by RSF consistently improves relative precision and design efficiency of elk population estimates, whether we employ pre- or poststratification. Where a RSF is available it could be used as a surrogate for animal densities when conducting stratified sampling for population surveys.     

Response of Elk to Changes in Plant Production and Nutrition Following Prescribed Burning

Abstract: Researchers have ascribed use of areas by grazers after burning to changes in plant community structure, community composition, nutritional quality, and seasonal availability. Researchers can better evaluate these alternatives if they monitor changes in plant communities following burning concurrently with changes in animal use. We examined responses of elk (Cervus elaphus) to prescribed burning of areas dominated by sagebrush (Artemisia spp.) in south-central Montana, USA, within which we monitored changes in plant production, nutritional quality, and community composition and diversity from 1989 to 1999. Elk increased use of burned sites 1–2 years after burning, then reduced use to levels associated with preburn conditions over the next 3–10 years. Burning transformed low-diversity, sagebrush-dominated communities into relatively high-diversity, grass- and forb-dominated communities that persisted for 10 years, but forage biomass and protein content declined on burned sites after initial short-term increases. Changes in elk use closely tracked changes in production and nutritional quality of plants. Therefore, we concluded that increases in quantity and quality of forage were the primary cause for increased use of burned sites by elk. Managers may observe only short-term responses from elk following burning but can expect longer-term increases in plant diversity and persistence of grass—forb communities on burned sites for >10 years that may be important to elk or other grazing ungulates.     

Dynamics of Newly Established Elk Populations

Abstract: The dynamics of newly established elk (Cervus elaphus) populations can provide insights about maximum sustainable rates of reproduction, survival, and increase. However, data used to estimate rates of increase typically have been limited to counts and rarely have included complementary estimates of vital rates. Complexities of population dynamics cannot be understood without considering population processes as well as population states. We estimated pregnancy rates, survival rates, age ratios, and sex ratios for reintroduced elk at Theodore Roosevelt National Park, North Dakota, USA; combined vital rates in a population projection model; and compared model projections with observed elk numbers and population ratios. Pregnancy rates in January (early in the second trimester of pregnancy) averaged 54.1% (SE = 5.4%) for subadults and 91.0% (SE = 1.7%) for adults, and 91.6% of pregnancies resulted in recruitment at 8 months. Annual survival rates of adult females averaged 0.96 (95% CI = 0.94-0.98) with hunting included and 0.99 (95% CI = 0.97-0.99) with hunting excluded from calculations. Our fitted model explained 99.8% of past variation in population estimates and represents a useful new tool for short-term management planning. Although we found no evidence of temporal variation in vital rates, variation in population composition caused substantial variation in projected rates of increase (Λ = 1.20-1.36). Restoring documented hunter harvests and removals of elk by the National Park Service led to a potential rate of Λ = 1.26. Greater rates of increase substantiated elsewhere were within the expected range of chance variation, given our model and estimates of vital rates. Rates of increase realized by small elk populations are too variable to support inferences about habitat quality or density dependence.