401 Gekeler Lane

La Grande, OR, United States

401 Gekeler Lane

La Grande, OR, United States
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Cook R.C.,National Council for Air and Stream Improvement Inc. | Cook J.G.,National Council for Air and Stream Improvement Inc. | Vales D.J.,Muckleshoot Indian Tribe | Johnson B.K.,401 Gekeler Lane | And 12 more authors.
Wildlife Monographs | Year: 2013

Demographic data show many populations of Rocky Mountain (Cervus elaphus nelsoni) and Roosevelt (Cervus elaphus roosevelti) elk have been declining over the last few decades. Recent work suggests that forage quality and associated animal nutritional condition, particularly in late summer and early autumn, influence reproduction and survival in elk. Therefore, we estimated seasonal nutritional condition of 861 female elk in 2,114 capture events from 21 herds in Washington, Oregon, Wyoming, Colorado, and South Dakota from 1998 to 2007. We estimated ingesta-free body fat and body mass, and determined age, pregnancy status, and lactation status. We obtained estimates for most herds in both late winter-early spring (late Feb-early Apr) and in autumn (Nov-early Dec) to identify changes in nutritional condition of individuals across seasons. Body fat levels of lactating females in autumn were consistently lower than their non-lactating counterparts, and herd averages of lactating elk ranged from 5.5% to 12.4%. These levels were 30-75% of those documented for captive lactating elk fed high-quality diets during summer and autumn. Body fat levels were generally lowest in the coastal and inland northwest regions and highest along the west-slope of the northern Cascades. Adult females in most herds lost an average of 30.7 kg (range: 5-62 kg), or about 13% (range: 2.6-25%) of their autumn mass during winter, indicating nutritional deficiencies. However, we found no significant relationships between spring body fat or change in body fat over winter with winter weather, region, or herd, despite markedly different winter weather among herds and regions. Instead, body fat levels in spring were primarily a function of fat levels the previous autumn. Thinner females in autumn lost less body fat and body mass over winter than did fatter females, a compensatory response, but still ended the season with less body fat than the fatter elk. Body fat levels of lactating females in autumn varied among herds but were unrelated to their body fat levels the previous spring. Within herds, thinner females exhibited a compensatory response during summer and accrued more fat than their fatter counterparts over summer, resulting in similar body fat levels among lactating elk in autumn despite considerable differences in their fat levels the previous spring. Level of body fat achieved by lactating females in autumn varied 2-fold among herds, undoubtedly because of differences in summer nutrition. Thus, summer nutrition set limits to rates of body fat accrual of lactating females that in turn limited body condition across the annual cycle. Pregnancy rates of 2- to 14-year-old females ranged from 68% to 100% in coastal populations of Washington, 69% to 98% in Cascade populations of Washington and Oregon, 84% to 94% in inland northwestern populations of Washington and Oregon, and 78% to 93% in Rocky Mountain populations. We found evidence of late breeding, even in herds with comparatively high pregnancy rates. Mean body mass of calves (n = 242) in 3 populations was 75 kg, 81 kg, and 97 kg, representing 55-70% of potential mass for 6- to 8-month-old calves on high-quality diets. Mean mass of 11 yearling females caught in autumn was 162 kg, approximately 70% of potential for autumn, and pregnancy rate was 27%. Mean mass of 28 yearlings caught in spring was 163 kg and pregnancy rate was 34%. Our data suggest widespread occurrence of inadequate summer nutrition. Summer ranges of just 3 herds supported relatively high levels of autumn body fat (11-13% body fat) and pregnancy rates (>90%) even among females that successfully raised a calf year after year. Most other summer ranges supported relatively low autumn levels of body fat (5-9% body fat), and reproductive pauses were common (<80% pregnancy rates). Overall, our data failed to support 2 common assumptions: 1) summer and early autumn foraging conditions are typically satisfactory to prevent nutritional limitations to adult fat accretion, pregnancy rates, and calf and yearling growth; and 2) winter nutrition and winter weather are the principal limiting effects on elk productivity. Instead, a strong interaction existed among level of summer nutrition, lactation status, and probability of breeding that was little affected by winter conditions - adequacy of summer nutrition dictated reproductive performance of female elk and growth as well as growth and development of their offspring in the Northwest and Rocky Mountains. Our work signals the need for greater emphasis on summer habitats in land management planning on behalf of elk. © 2013 The Wildlife Society.

Warren M.J.,401 Gekeler Lane | Wallin D.O.,Western Washington University
Conservation Genetics | Year: 2016

Population structure, connectivity, and dispersal success of individuals can be challenging to demonstrate for solitary carnivores with low population densities. Though the cougar (Puma concolor) is widely distributed throughout North America and is capable of dispersing long distances, populations can be geographically structured and genetic isolation has been documented in some small populations. We described genetic structure and explored the relationship between landscape resistance and genetic variation in cougars in Washington and southern British Columbia using allele frequencies of 17 microsatellite loci for felids. We evaluated population structure of cougars using the Geneland clustering algorithm and spatial principal components analysis. We then used Circuitscape to estimate the landscape resistance between pairs of individuals based on rescaled GIS layers for forest canopy cover, elevation, human population density and highways. We quantified the effect of landscape resistance on genetic distance using multiple regression on distance matrices and boosted regression tree analysis. Cluster analysis identified four populations in the study area. Multiple regression on distance matrices and boosted regression tree models indicated that only forest canopy cover and geographic distance between individuals had an effect on genetic distance. The boundaries between genetic clusters largely corresponded with breaks in forest cover, showing agreement between population structure and genetic gradient analyses. Our data indicate that forest cover promotes gene flow for cougars in the Pacific Northwest, which provides insight managers can use to preserve or enhance genetic connectivity. © 2016 Springer Science+Business Media Dordrecht

Clark D.A.,Oregon State University | Johnson B.K.,401 Gekeler Lane
Northwest Science | Year: 2015

Cougar (Puma concolor) kittens are a substantial proportion of resident cougar populations and their survival has important implications for population dynamics of the species. To better understand effects of age and sex on cougar kitten survival, we estimated age specific (mo.) survival rates of cougar kittens (n = 72) radiocollared during three studies conducted in Oregon from 1989-2011. Cougar kittens were entered into the dataset based on age (mo.) at capture and fates were determined at monthly intervals. We analyzed survival in Program MARK using known-fate models of radiocollared individuals. We tested for effects of sex and linear, log-linear, and quadratic effects of age. Our best model indicated survival rates of cougar kittens were similar between sexes and increased in a linear manner with age. Annual survival estimates of cougar kittens were 0.66 (95% CI = 0.42-0.84). Our second ranked model was the null model, that indicated constant survival over time and between sexes with an annual survival rate of 0.78 (95% CI = 0.62-0.88). All other models in our candidate model set were not considered further because they ranked below the null model and contained non-informative parameters where the estimated effect broadly overlapped zero. Fates of littermates were dependent due to high levels of mortality at nursery sites which likely reduced the potential importance of sex on survival rates. We expect patterns of increased kitten survival with age and lack of differences between sexes to be consistent across the geographic range of cougars. © 2015 by the Northwest Scientific Association. All rights reserved.

Clark D.A.,Oregon State University | Johnson B.K.,401 Gekeler Lane | Henjum M.,07 20th Street | Henjum M.,U.S. Department of Agriculture | And 3 more authors.
Journal of Wildlife Management | Year: 2014

Cougar (Puma concolor) management in Oregon is unique because hunting cougars with dogs was allowed through the 1994 hunting season, but thereafter Ballot Initiative Measure 18 prohibited the use of dogs to pursue cougars. Since 1995, hunting seasons have become increasingly longer with more tags sold. The effects of changing management structure on survival rates and causes of mortality of cougars are not well understood. We investigated survival and documented causes of mortality of radiocollared cougars at 3 study areas in Oregon from 1989 to 2011 under contrasting management strategies. The Catherine Creek (1989-1996) and Jackson Creek (1993-2002) studies overlapped the prohibition of hunting cougars with dogs, and the Wenaha, Sled Springs, and Mt. Emily (WSM) study was conducted from 2002 to 2011 when hunting cougars with dogs was illegal. Hunting mortality was the most common cause of death for sub-adult and adult cougars in Catherine Creek pre- (18 of 23 mortalities) and post-Measure 18 (1 of 2 mortalities) and WSM (24 of 53 mortalities) study areas in northeast Oregon. In contrast, natural mortality was the most common cause of death of sub-adults and adults at the Jackson Creek (25 of 38 mortalities) study area in southwest Oregon, but hunting mortality was most common prior to the passage of Measure 18 (3 of 3 mortalities). We estimated annual survival rates of cougars using known fate models in Program MARK. Annual survival rates of adult males were lowest at Catherine Creek prior to the passage of Measure 18 (Ŝ=0.57; 95% CI=0.39-0.73) and increased after Measure 18 (Ŝ=0.86; 95% CI=0.79-0.92), which were similar to those rates observed at Jackson Creek pre- and post-Measure 18 (Ŝ=0.78; 95% CI=0.65-0.88) and WSM (Ŝ=0.82; 95% CI=0.69-0.91). Regardless of hunting regulations, annual survival rates of adult females was similar among study areas (Catherine Creek pre- and post-Measure 18 [Ŝ=0.86; 95% CI=0.79-0.92]; Jackson Creek pre- and post-Measure 18 [Ŝ=0.85; 95% CI=0.77-0.91]; WSM [Ŝ=0.85; 95% CI=0.76-0.90]). At Jackson Creek pre- and post-Measure 18 and WSM, sub-adult males (1-3 years) had significantly lower survival than sub-adult females, but survival rates of males and females were similar by age 4 or 5 years. At WSM, survival declined for both sexes at older ages (8-13 years), but this decline was not observed at Jackson Creek pre- or post-Measure 18. The effect of increasing age on cougar survival should be considered when using survival rates to estimate population growth rates. We did not detect an effect of age on cougar survival at the Catherine Creek study area pre- or post-Measure 18, which we attributed to selective harvest of prime-aged, male cougars prior to the passage of Measure 18 and lack of mortality post-Measure 18. Managers should understand local sources of mortality when setting harvest regulations because sources of mortality may vary widely within and among jurisdictions, even if management practices are similar. Because of low hunter success rates when hunting cougars without dogs, survival rates of cougars managed under this hunting regime should be substantially higher than areas where use of dogs is legal. This suggests the ability of managers to effectively manipulate survival rates of cougars to meet population management objectives will be dependent on available hunting methods. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. © Published 2014. This article is a U.S. Government work and is in the public domain in the USA. Wildlife Society Bulletin published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

Kie J.G.,Idaho State University | Kie J.G.,U.S. Department of Agriculture | Johnson B.K.,401 Gekeler Lane | Noyes J.H.,NE Vandenberg Ave. | And 5 more authors.
Wildlife Biology | Year: 2013

Our objective was to examine effects of groups of mixed numbers and ages of male North American elk Cervus elaphus on the reproductive performance of females. We conducted research at the Starkey Experimental Forest and Range in northeastern Oregon, USA, during 1993-2000. Each spring in late March, we released 40 female elk, eight yearling (9-month old) male elk and 2-8 branch-antlered elk (i.e. ≥ 2 years of age during rut the following autumn) into a 622-ha fenced pasture. Elk were gathered during autumn and early winter, and were brought to winter feeding grounds where blood samples were drawn to determine pregnancy status. The following spring, females were released into an 80-ha pasture prior to parturition. We searched for and captured newborn calves and obtained ear-punch samples for genetic analysis. We used 18 microsatellite loci to establish paternity of each calf. We varied the ratio of mature males (i.e. ≥ 3 years old) to female ratio from 0.03 to 0.21. As expected, mature males (older and heavier) were more successful in siring calves than were younger males. Within age classes, however, body mass in spring did not accurately predict mating success in autumn. Reproductive rates were not affected by season of grazing by cattle, yearling male to female ratio or mature male to female ratio. Sire age had no effect on mean dates of calf births or on calf weights. Neither sire age nor season of grazing by cattle had significant effects on calf weights; however, mean date of birth was significantly earlier when cattle grazing occurred during the previous autumn than when cattle grazed during the preceding spring. Furthermore, the number of calves sired by yearling males was greater when cattle grazing occurred during autumn, than when grazing occurred during spring. In the years with disruptive cattle grazing during rut, females mated not only with yearling males, in general, but often with those who were lighter in body mass during the previous spring than others in the same cohort. The extent to which those yearling males are untested in combat with older, dominant herd bulls may have genetic consequences leading to differences in fitness and subsequent reductions in calf survival. Please note that the supplementary information, including Appendix SI mentioned in this article, is available in the online version of this article, which can be viewed at www.wildlifebiology.com. © 2013 Wildlife Biology, NKV.

Johnson B.K.,401 Gekeler Lane | Coe P.K.,401 Gekeler Lane | Green R.L.,118 NE Vandenberg Avenue
Journal of Wildlife Management | Year: 2013

Understanding the relative effects of the many factors that may influence recruitment of ungulates is fundamental to managing their populations. Over the last 4 decades, average recruitment in some populations of elk (Cervus elaphus) in Oregon, USA declined from >50 to <20 juveniles per 100 females, and several competing hypotheses address these declines. We developed a priori models and constructed covariates spanning 1977-2005 from hunter-killed elk, elk population estimates, cougar harvest, and weather statistics to evaluate abiotic, bottom-up, and top-down factors that may explain annual variation and long-term trends of pregnancy, juveniles-at-heel in late autumn, and recruitment of juvenile elk in spring. In models of pregnancy status, August precipitation, age, and cougar index had positive effects, whereas previous year (t - 1) winter severity or winter precipitation(t-1) and elk density had negative effects. In models of juvenile-at-heel in late autumn, August precipitation, August precipitation(t-1), cougar index × elk density(t-1), and age had positive effects, whereas cougar index, elk density(t-1), and winter precipitation(t-1) had negative effects. Juvenile recruitment was best explained by positive effects of August precipitation(t-1), lactation rate, and cougar index × elk density(t-1) and negative effects of cougar index and elk density(t-1). Winter severity, precipitation, and temperature were not significant in explaining variation in elk recruitment. Annual variation in pregnancy, juvenile-at-heel, and recruitment was most influenced by August precipitation, whereas long-term trends in recruitment were most influenced by cougar densities with relatively weak effects of elk density. These results provide insight into causes of year-to-year and long-term trends of elk recruitment and provide a basis for more rigorous evaluation of factors affecting recruitment of elk. Copyright © 2012 The Wildlife Society.

Dick B.L.,Pacific Northwest Research Station | Findholt S.L.,401 Gekeler Lane | Johnson B.K.,401 Gekeler Lane
Wildlife Society Bulletin | Year: 2013

It is a challenge to use collars on male cervids because their neck size can increase substantially during the rut and also because of growth as the animal matures. We describe how to build a self-adjusting expandable collar for yearling or adult male Rocky Mountain elk (Cervus elaphus) to which very high frequency transmitters and global positioning system (GPS) units can be attached. We evaluated performance and durability of 35 expandable collars placed on male elk from 2009 through 2011 within the Starkey Experimental Forest and Range enclosure, Northeast Oregon, USA. Twenty-four (69%) collars remained on elk throughout our sampling period for GPS fixes from March or April to 1 November each year. Eight (23%) collars broke before 1 November and 3 (9%) collars were removed when males were harvested by hunters. Six of 8 collars that broke before 1 November came off during the rut. Mean date these collars broke was 19 September (SE=7.1 days, 95% CI=1 Sept. to 7 Oct.). Excluding 1 collar still being worn by a male elk and those collars either recovered when males were harvested by hunters (3) or removed from adult males on the winter feed ground (7), mean number of days collars stayed on was 279 (SE=25.5, 95% CI=225.8-331.3 days). No deaths or injuries were attributed to the collars. Because these collars can break, especially during the rut, we recommend sample sizes of males be increased ≥25% to compensate for collars that may come off during that period. Collars are not recommended for multi-year studies of male elk without substantial modifications to our design and further testing. © 2013 The Wildlife Society.

Clark D.A.,Oregon State University | Davidson G.A.,401 Gekeler Lane | Johnson B.K.,401 Gekeler Lane
Journal of Wildlife Management | Year: 2014

Cougars (Puma concolor) are a primary predator of mule deer (Odocoileus hemionus) and elk (Cervus elaphus) throughout western North America. Effective management of predator-prey systems requires a solid understanding of kill rates, prey use, and selection. We implemented a 3-year study in northeast Oregon to investigate cougar diet, kill rates, and prey selection in a multiple-prey system to assess the degree to which patterns in cougar predation may be generalizable across systems and to identify selective predation patterns of cougars that may affect ungulate populations. We marked 25 adult cougars with global positioning system (GPS) collars and monitored predation sequences for 7,642 days to identify kill sites. In field investigation of kill sites, we identified remains of 1,213 prey items killed by cougars, of which 1,158 (95.4%) were native ungulates. On average, cougars killed 1.03 ungulates/week (95% CI = 0.92-1.14), but kill rates varied by season, sex, and reproductive status of cougars. Cougars killed ungulate prey 1.55 (95% CI = 1.47-1.66) times more frequently during summer (May-Oct) than winter (Nov-Apr). Kill rates were higher in summer because juvenile ungulates were the most frequently killed prey item and were smaller than prey killed in winter. Female cougars with kittens >6 months old killed prey more frequently than males, solitary females, and females with kittens <6 months old likely in response to the increased energetic burden of raising kittens. Male cougars killed larger prey than females, which likely explains why males killed at similar rates as solitary females, despite the larger body size of males. We documented patterns in prey selection influenced by season and demographic classification of cougars. Diets of male cougars included roughly equal amounts of elk (52.2%) and deer (47.8%), whereas diets of females were dominated by deer (74.6%). Male and female cougars displayed strong patterns of selection for elk calves during summer. During winter, female cougars selected deer fawns and males selected elk calves. Female cougars with kittens >6 months old demonstrated little selection for any age class or species of prey, highlighting an opportunistic foraging strategy to maximize energy gains while feeding young. Across all cougars, we observed a pattern of selection for adult male deer during winter but not summer and did not observe patterns of selection for adult elk according to sex. Our results strongly supported the hypothesis proposed by [Knopff et al. (2010) Journal of Wildlife Management, 74: 1435-1447] that cougar predation is influenced by season and demographic classifications of cougars and our results provide strong evidence that this hypothesis should be generalizable to other areas. The patterns of selection for juvenile elk and deer suggested wildlife managers should consider the potential negative effects of cougars on ungulate populations in areas where juvenile recruitment has been chronically low. © 2014 The Wildlife Society. © The Wildlife Society, 2014.

Davidson G.A.,401 Gekeler Lane | Johnson B.K.,401 Gekeler Lane | Noyes J.H.,401 Gekeler Lane | Dick B.L.,U.S. Department of Agriculture | Wisdom M.J.,U.S. Department of Agriculture
Journal of Wildlife Management | Year: 2012

Archery hunting in Oregon has increased dramatically over the past 2 decades. At the same time, spring juvenile to adult female ratios of Rocky Mountain elk (Cervus elaphus) have been declining. This has raised concern that archery seasons may be disrupting elk breeding and contributing to the decline in recruitment. Two mechanisms could contribute to reduced juvenile:female ratios: 1) reduced pregnancy rates, and 2) delayed conception dates because of human disturbance during the rut. We varied the number of archery hunters at the Starkey Experimental Forest and Range over 13 years to evaluate effects of archer density on reproduction of elk. Archer densities were maintained at high densities during 4 years (x̄= 1.09 tags sold/km 2), low densities during 3 years (x̄= 0.5 tags sold/km 2), and no archers during 6 years. We determined pregnancy status, age, kidney fat index (KFI), lactation status, and fetus conception dates for 622 female elk harvested in December. We found pregnancy rate differences of 0.105, 0.080, and 0.021 between high and no archer density years (P = 0.004), high and low archer density years (P = 0.054), and low and no archer density years (P = 0.616), respectively. Conception dates were 4 days later for high archer density compared to low archer density (P = 0.006), but did not differ between high and no archer years (2 days; P = 0.136) or between low and no archer years (2 days; P = 0.108). We compared generalized linear model estimates of pregnancy rates and determined pregnancy rates for 28% of the lactating female elk to be affected by high archer density, whereas archer densities had no significant affect on pregnancy rate estimates for non-lactating females. We found no difference in conception dates among archer densities when comparing model estimates. Our results suggest that archer density and its interaction with nutritional condition of elk influence pregnancy rates of lactating females with low KFI levels; however, the effect of archer density alone does not explain the magnitude of decline in juvenile to female ratios observed in Oregon. © 2012 The Wildlife Society. Copyright © The Wildlife Society, 2012.

Rearden S.N.,Oregon State University | Anthony R.G.,Oregon State University | Johnson B.K.,401 Gekeler Lane
Journal of Mammalogy | Year: 2011

We investigated the effects of predation risk on birth-site selection by Rocky Mountain elk (Cervus elaphus nelsoni) during summer in 2002-2004 in northeastern Oregon at macrohabitat (3rd-order selection) and microhabitat (4th-order selection) scales. This study describes vegetative characteristics of birth sites selected by female elk when young <4-5 days old used the hiding strategy and predation sites when most predation events occurred on young >5 days old that used the fleeing strategy. At the macrohabitat scale we observed no evidence that female elk were influenced by predation risk when selecting a birth site on the basis of variables measured in this study. Females chose birth sites with less overhead cover than random sites, suggesting that they might have been influenced more by forage availability than predation risk. At the microhabitat scale females selected birth sites that had more overhead canopy cover and greater visibility at ground level than paired random sites, which suggested that birth-site selection at this scale was influenced by predation risk. Together, these results suggested that female elk selected areas for parturition at the macrohabitat scale that likely had forage to meet high nutritional demands of lactation and at the microhabitat scale selected areas that provided visibility to detect predators and reduce the risk of predation. Predators, mainly cougars (Puma concolor), killed young in areas closer to vegetative edges at the macrohabitat scale and with more visibility at the microhabitat scale. These areas were likely conducive to cougar hunting where sight and cover from forest edges can be important for stalking calves that are traveling with their mothers and family groups. © 2011 American Society of Mammalogists.

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