Wildlife Monographs最新文献

{"title":"Ecology of Florida Black Bears in the Okefenokee-Osceola Ecosystem","authors":"STEVEN DOBEY, DARRIN V. MASTERS, BRIAN K. SCHEICK, JOSEPH D. CLARK, MICHAEL R. PELTON, MELVIN E. SUNQUIST","doi":"10.2193/0084-0173(2005)158[1:EOFBBI]2.0.CO;2","DOIUrl":"https://doi.org/10.2193/0084-0173(2005)158[1:EOFBBI]2.0.CO;2","url":null,"abstract":"<p><b>Abstract: </b> The population status of the Florida black bear (<i>Ursus americanus floridanus</i>) is problematic within many portions of its range and its potential listing as a federally threatened species has been the subject of legal debate. We studied Florida black bears in 2 areas in the Okefenokee-Osceola ecosystem in southeast Georgia (i.e., Okefenokee) and north Florida (i.e., Osceola) from 1995 to 1999 to evaluate relationships between population characteristics, habitat conditions, and human activities. Bears in Okefenokee were hunted and those in Osceola were not. We captured 205 different black bears (124M:81F) 345 times from June 1995 to September 1998. We obtained 13,573 radiolocations from 87 (16M:71F) individual bears during the study.</p><p>In Okefenokee, black gum (<i>Nyssa sylvatica</i>) and saw palmetto (<i>Serenoa repens</i>) fruits were the most important foods for bears based on scat analysis. In Osceola, corn from white-tailed deer (<i>Odocoileus virginianus</i>) feeders was the most stable food source but saw palmetto was heavily used when available. Corn from deer feeders was not available in Okefenokee. Adult bears in Osceola were 29% heavier than those in Okefenokee (<i>t</i><sub>82</sub> = 3.55, <i>P</i> < 0.001).</p><p>The mean annual home-range size for Osceola females (x = 30.3 km<sup>2</sup> ± 4.0 [SE], <i>n</i> = 53) varied little seasonally or annually and was almost half that of Okefenokee females (55.9 km<sup>2</sup> ± 6.9, <i>n</i> = 69; <i>Z</i> = −2.47, <i>P</i> = 0.014). In contrast, radiocollared females in Okefenokee expanded their home ranges during years of poor black gum production. That expansion was most apparent between autumn 1998 and 1999, when mean home-range size for Okefenokee females increased from 14.5 km<sup>2</sup> to 78.4 km<sup>2</sup>, respectively, and included a larger proportion of upland areas open to sport hunting. As a result, 5 females were harvested in the Okefenokee study area during the 1999 bear hunting season compared with only 7 harvested from 1996 to 1998.</p><p>Home ranges of adult female bears were located in areas with disproportionately high loblolly bay (<i>Gordonia lasianthus</i>) and gum-bay-cypress (<i>Taxodium</i> spp.) vegetation associations in Okefenokee and gum-bay-cypress associations in Osceola. The pine vegetation association ranked lower than most other associations within the home ranges of bears in both study areas even though much of the summer and autumn diets of bears included food items found almost exclusively in pine.</p><p>Sixteen mortalities of radiocollared bears were documented in Okefenokee; hunting accounted for 11 (68.8%) of these deaths. The annual survival rate of radiocollared males in Okefenokee was 0.71 (95% CI = 0.53-0.88) whereas survival of females in Okefenokee was higher (<i>Z</i> = 18.87, <i>P</i> < 0.001) at 0.89 (95% CI = 0.83-0.95). The survival rate for females in Osceola was 0.97 (95% CI = 0.92-1.00). Overall, 6","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"158 1","pages":"1-41"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/0084-0173(2005)158[1:EOFBBI]2.0.CO;2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6207321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Enhanced Nutrition on Mule Deer Population Rate of Change","authors":"CHAD J. BISHOP, GARY C. WHITE, DAVID J. FREDDY, BRUCE E. WATKINS, THOMAS R. STEPHENSON","doi":"10.2193/2008-107","DOIUrl":"https://doi.org/10.2193/2008-107","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> ABSTRACT</h3>\u0000 \u0000 <p>Concerns over declining mule deer (<i>Odocoileus hemionus</i>) populations during the 1990s prompted research efforts to identify and understand key limiting factors of deer. Similar to past deer declines, a top priority of state wildlife agencies was to evaluate the relative importance of habitat and predation. We therefore evaluated the effect of enhanced nutrition of deer during winter and spring on fecundity and survival rates using a life table response experiment involving free-ranging mule deer on the Uncompahgre Plateau in southwest Colorado, USA. The treatment represented an instantaneous increase in nutritional carrying capacity of a pinyon (<i>Pinus edulis</i>)—Utah juniper (<i>Juniperus osteosperma</i>) winter range and was intended to simulate optimum habitat quality. Prior studies on the Uncompahgre Plateau indicated predation and disease were the most common proximate causes of deer mortality. By manipulating nutrition and leaving natural predation unaltered, we determined whether habitat quality was ultimately a critical factor limiting the deer population. We measured annual survival and fecundity of adult females and survival of fawns, then estimated population rate of change as a function of enhanced nutrition. Pregnancy and fetal rates of adult females were high and did not vary in response to treatment. Fetal and neonatal survival rates increased in response to treatment, although the treatment effect on neonatal survival was marginal. Overwinter rates of fawn survival increased for treatment deer by 0.16–0.31 depending on year and fawn sex, and none of the 95% confidence intervals associated with the effects overlapped zero. Overwinter rates of fawn survival averaged 0.905 (SE = 0.026) for treatment deer and 0.684 (SE = 0.044) for control deer. Nutritional enhancement increased survival rates of fetuses to the yearling age class by 0.14–0.20 depending on year and fawn sex; 95% confidence intervals slightly overlapped zero. When averaging estimates across sexes and years, treatment caused fetal to yearling survival to increase by 0.177 (SE = 0.082, 95% CI: 0.016–0.337). Annual survival of adult females receiving treatment (<i>Ś</i> = 0.879, SE = 0.021) was higher than survival of control adult females (<i>Ś</i> = 0.833, SE = 0.025). Our estimate of the population rate of change (λ) was 1.165 (SE = 0.036) for treatment deer and 1.033 (SE = 0.038) for control deer. Increased production and survival of young (i.e., fetal, neonatal, and overwinter fawn survival) accounted for 64% of the overall increase in λ, whereas adult female survival accounted for 36% of the increase in λ. The effect of nutrition treatment on overwinter fawn survival alone accounted for 33% of the overall increase in λ.</p>\u0000 \u0000 <p>We documented food limitation in the Uncompahgre deer population because survival of fawns and adult fe","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"172 1","pages":"1-28"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/2008-107","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6207309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Status and Trends in Demography of Northern Spotted Owls, 1985–2003","authors":"ROBERT G. ANTHONY, ERIC D. FORSMAN, ALAN B. FRANKLIN, DAVID R. ANDERSON, KENNETH P. BURNHAM, GARY C. WHITE, CARL J. SCHWARZ, JAMES D. NICHOLS, JAMES E. HINES, GAIL S. OLSON, STEVEN H. ACKERS, LAWRENCE S. ANDREWS, BRIAN L. BISWELL, PETER C. CARLSON, LOWELL V. DILLER, KATIE M. DUGGER, KATHERINE E. FEHRING, TRACY L. FLEMING, RICHARD P. GERHARDT, SCOTT A. GREMEL, R. J. GUTIERREZ, PATTI J. HAPPE, DALE R. HERTER, J. MARK HIGLEY, ROBERT B. HORN, LARRY L. IRWIN, PETER J. LOSCHL, JANICE A. REID, STAN G. SOVERN","doi":"10.2193/0084-0173(2006)163[1:SATIDO]2.0.CO;2","DOIUrl":"https://doi.org/10.2193/0084-0173(2006)163[1:SATIDO]2.0.CO;2","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> ABSTRACT</h3>\u0000 \u0000 <p>We analyzed demographic data from northern spotted owls (<i>Strix occidentalis caurina</i>) from 14 study areas in Washington, Oregon, and California for 1985–2003. The purpose of our analyses was to provide an assessment of the status and trends of northern spotted owl populations throughout most of their geographic range. The 14 study areas made up approximately 12% of the range of the subspecies and included federal, tribal, private, and mixed federal and private lands. The study areas also included all the major forest types that the subspecies inhabits. The analyses followed rigorous protocols that were developed a priori and were the result of extensive discussions and consensus among the authors. Our primary objectives were to estimate fecundity, apparent survival (ϕ), and annual rate of population change (λ) and to determine if there were any temporal trends in these population parameters. In addition to analyses of data from individual study areas, we conducted 2 meta-analyses on each demographic parameter. One meta-analysis was conducted on all 14 areas, and the other was restricted to the 8 areas that constituted the Effectiveness Monitoring Plan for northern spotted owls under the Northwest Forest Plan. The average number of years of reproductive data per study area was 14 (range = 5–19), and the average number of recapture occasions per study area was 13 (range = 4–18). Only 1 study area had <12 years of data. Our results were based on 32,054 captures and resightings of 11,432 banded individuals for estimation of survival and 10,902 instances in which we documented the number of young produced by territorial females.</p>\u0000 \u0000 <p>The number of young fledged (NYF) per territorial female was analyzed by testing a suite of a priori models that included (1) effects of age, (2) linear or quadratic time trends, (3) presence of barred owls (<i>Strix varia</i>) in spotted owl territories, and (4) an even-odd year effect. The NYF varied among years on most study areas with a biennial cycle of high reproduction in even-numbered years and low reproduction in odd-numbered years. These cyclic fluctuations did not occur on all study areas, and the even-odd year effect waned during the last 5 years of the study. Fecundity was highest for adults (<i>x̄</i> =0.372, SE = 0.029), lower for 2-year-olds (<i>x̄</i> = 0.208, SE = 0.032), and very low for 1-year-olds (<i>x̄</i> = 0.074, SE = 0.029). Fecundity was stable over time for 6 areas (Rainier, Olympic, Warm Springs, H. J. Andrews, Klamath, and Marin), declining for 6 areas (Wenatchee, Cle Elum, Oregon Coast Range, Southern Oregon Cascades, Northwest California, and Simpson), and slightly increasing for 2 areas (Tyee, Hoopa). We found little association between NYF and the proportion of northern spotted owl territories where barred owls were detected, although results were ","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"163 1","pages":"1-48"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/0084-0173(2006)163[1:SATIDO]2.0.CO;2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6207316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cumulative Effects of Human Developments on Arctic Wildlife","authors":"CHRIS J. JOHNSON, MARK S. BOYCE, RAY L. CASE, H. DEAN CLUFF, ROBERT J. GAU, ANNE GUNN, ROBERT MULDERS","doi":"10.2193/0084-0173(2005)160[1:CEOHDO]2.0.CO;2","DOIUrl":"https://doi.org/10.2193/0084-0173(2005)160[1:CEOHDO]2.0.CO;2","url":null,"abstract":"<p><b>Abstract: </b> Recent discoveries of diamondiferous kimberlite deposits in the Canadian central Arctic led to unprecedented levels of mineral exploration and development. The cumulative effects of such activities are an issue of concern for government regulatory agencies, regional and international conservation organizations, wildlife managers, and indigenous peoples. We investigated the impacts of human activities and associated infrastructure on the distribution of Arctic wildlife in 190,000 km<sup>2</sup> of the Taiga Shield and Southern Arctic ecozones 400 km northeast of Yellowknife, Northwest Territories, Canada.</p><p>We used covariates for vegetation, interspecific interactions, and human disturbance features to develop seasonal resource-selection models for barren-ground caribou (<i>Rangifer tarandus groenlandicus</i>), gray wolves (<i>Canis lupus</i>), grizzly bears (<i>Ursus arctos</i>), and wolverines (<i>Gulo gulo</i>). We used an information-theoretic approach to select 11 seasonal models for the 4 species. Nine models were good predictors of species occurrence and vegetation covariates were important components of all models. Mines and other major developments had the largest negative affect on species occurrence, followed by exploration activities, and outfitter camps. We did not, however, record strong avoidance responses by all species during all seasons to each disturbance type (i.e., major developments, mineral exploration sites, outfitter camps) and for some models carnivores selected for disturbance features (i.e., occurred closer to sites than comparison random locations). We used a geographic information system (GIS) to extrapolate each seasonal resource-selection model to the study area and quantified the reduction in habitat effectiveness as a function of modeled and hypothetical disturbance coefficients. Across all models, grizzly bears and wolves demonstrated the strongest negative response to disturbance and corresponding reduction in habitat effectiveness, followed by caribou and wolverines. The largest seasonal effect was recorded for caribou during the post-calving period, where model coefficients suggested a 37% reduction in the area of the highest quality habitats and an 84% increase in the area of the lowest quality habitats.</p><p>This is the first study to demonstrate the cumulative effects of multiple sources of human disturbance for caribou, wolves, bears, and wolverines found across the Canadian central Arctic. Resource selection models and corresponding maps of important habitats can be used to guide and evaluate future development proposals and can serve as a component of a regional environmental assessment. However, inferences from large-scale modeling efforts should be carefully evaluated when making detailed prescriptive recommendations. Study design, sample size, reliability of GIS data, and accuracy of model predictions are important considerations when evaluating the strength and scale of infe","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"160 1","pages":"1-36"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/0084-0173(2005)160[1:CEOHDO]2.0.CO;2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6218751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Military Operations on Behavior and Hearing of Endangered Sonoran Pronghorn","authors":"PAUL R. KRAUSMAN, LISA K. HARRIS, CATHY L. BLASCH, KIANA K. G. KOENEN, JON FRANCINE","doi":"10.2193/0084-0173(2004)157[1:EOMOOB]2.0.CO;2","DOIUrl":"https://doi.org/10.2193/0084-0173(2004)157[1:EOMOOB]2.0.CO;2","url":null,"abstract":"<p><b>Abstract: </b> Our objectives in this study were to determine whether military activities (e.g., overflight noise, noise from ordnance delivery, ground-based human activity) on the Barry M. Goldwater Range (BMGR) affect the behavior and hearing of Sonoran pronghorn (<i>Antilocapra americana sonoriensis</i>). We contrasted the behavior of pronghorn on BMGR with the closest population of pronghorn in the United States that was not subjected to routine military activity (i.e., on the Buenos Aires National Wildlife Refuge [BANWR], Arizona). Forty percent of the landscape used by the endangered Sonoran pronghorn in the United States is within the 5,739 km<sup>2</sup> BMGR, a bombing and gunnery facility in southwestern Arizona. The range of Sonoran pronghorn covers about 88% of BMGR. The 179 Sonoran pronghorn that lived in the United States in December 1992 declined to 99 by December 2000. The Sonoran pronghorn has been listed as endangered for >30 years, but population limiting factors are unknown. Because Sonoran pronghorn use BMGR, land and wildlife managers raised concerns about the potential effects of military activities on the population. Possible indirect effects of military activities on Sonoran pronghorn, aside from direct mortality or injury, from ordnance delivery, chaff, flares, live ammunition, aircraft mishaps, interference from ground vehicles and personnel, include alteration of behavior or physiology.</p><p>We conducted the study on the North and South Tactical Ranges (NTAC and STAC), BMGR, from February 1998 to June 2000. Hearing exams were conducted in Camp Verde, Arizona, the University of Arizona, and on the East Tactical Range (ETAC), BMGR. Interactions between pronghorn and military activity were restricted to 4 observation points that provided viewing areas from which pronghorn and military activity could be observed from ≤ 10 km. We systematically located pronghorn with spotting scopes and telemetry. When located, we described their behavior and military activity using scan sampling. We tested hearing using auditory brainstem responses (ABR). We could not test the hearing of Sonoran pronghorn because of their endangered status, so we contrasted hearing of pronghorn near Camp Verde, Arizona, and desert mule deer (<i>Odocoileus hemionus eremicus</i>) that were and were not exposed to sound pressure levels from military activity. We recorded behavior observations of Sonoran pronghorn on 172 days (44,375 observation events [i.e., 1 observation/30 second]) over 373 hours. These data were compared with 93 days of behavioral data (24,297 observation events) over 202 hours for pronghorn not regularly influenced by military aircraft. Overall, we did not detect behavioral differences (i.e., time spent bedding, standing, foraging, traveling) between males and females. Pronghorn exposed to military activity, and those that were not, bedded the same amount of time. Pronghorn at BMGR foraged less and stood and traveled more than p","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"157 1","pages":"1-41"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/0084-0173(2004)157[1:EOMOOB]2.0.CO;2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5667667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ruffed Grouse Population Ecology in the Appalachian Region","authors":"PATRICK K. DEVERS, DEAN F. STAUFFER, GARY W. NORMAN, DAVE E. STEFFEN, DARROCH M. WHITAKER, JEFFREY D. SOLE, TOM J. ALLEN, STEVE L. BITTNER, DAVID A. BUEHLER, JOHN W. EDWARDS, DANIEL E. FIGERT, SCOTT T. FRIEDHOFF, WILLIAM W. GIULIANO, CRAIG A. HARPER, WILLIAM K. IGO, ROY L. KIRKPATRICK, MICHAEL H. SEAMSTER, HARRY A. SPIKER Jr., DAVID A. SWANSON, BRIAN C. TEFFT","doi":"10.2193/0084-0173.168","DOIUrl":"https://doi.org/10.2193/0084-0173.168","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> ABSTRACT</h3>\u0000 \u0000 <p>The Appalachian Cooperative Grouse Research Project (ACGRP) was a multistate cooperative effort initiated in 1996 to investigate the apparent decline of ruffed grouse (<i>Bonasa umbellus</i>) and improve management throughout the central and southern Appalachian region (i.e., parts of Ohio, Pennsylvania, Rhode Island, Kentucky, West Virginia, Virginia, and North Carolina, USA). Researchers have offered several hypotheses to explain the low abundance of ruffed grouse in the region, including low availability of early-successional forests due to changes in land use, additive harvest mortality, low productivity and recruitment, and nutritional stress. As part of the ACGRP, we investigated ruffed grouse population ecology. Our objectives were to estimate reproductive rates, estimate survival and cause-specific mortality rates, examine if ruffed grouse harvest in the Appalachian region is compensatory, and estimate ruffed grouse finite population growth. We trapped >3,000 ruffed grouse in autumn (Sep-Nov) and spring (Feb-Mar) from 1996 to September 2002 on 12 study areas. We determined the age and gender of each bird and fitted them with necklace-style radiotransmitters and released them at the trap site. We tracked ruffed grouse ≥2 times per week using handheld radiotelemetry equipment and gathered data on reproduction, recruitment, survival, and mortality.</p>\u0000 \u0000 <p>Ruffed grouse population dynamics in the Appalachian region differed from the central portion of the species' range (i.e., northern United States and Canada). Ruffed grouse in the Appalachian region had lower productivity and recruitment, but higher survival than reported for populations in the Great Lakes region and southern Canada. Population dynamics differed between oak (<i>Quercus</i> spp.)–hickory (<i>Carya</i> spp.) and mixed-mesophytic forest associations within the southern and central Appalachian region. Productivity and recruitment were lower in oak-hickory forests, but adult survival was higher than in mixed-mesophytic forests. Furthermore, ruffed grouse productivity and recruitment were more strongly related to hard mast (i.e., acorn) production in oak-hickory forests than in mixed-mesophytic forests. The leading cause of ruffed grouse mortality was avian predation (44% of known mortalities). Harvest mortality accounted for 12% of all known mortalities and appeared to be compensatory. Population models indicated ruffed grouse populations in the Appalachian region are declining (%LD = 0.78–0.95), but differences in model estimates highlighted the need for improved understanding of annual productivity and recruitment. We posit ruffed grouse in the Appalachian region exhibit a clinal population structure characterized by changes in life-history strategies. Changes in life history strategies are in response to gradual changes in forest structure, qu","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"168 1","pages":"1-36"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/0084-0173.168","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6235263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EFFECTS OF SUMMER-AUTUMN NUTRITION AND PARTURITION DATE ON REPRODUCTION AND SURVIVAL OF ELK","authors":"JOHN G. COOK, BRUCE K. JOHNSON, RACHEL C. COOK, ROBERT A. RIGGS, TIM DELCURTO, LARRY D. BRYANT, LARRY L. IRWIN","doi":"10.2193/0084-0173(2004)155[1:EOSNAP]2.0.CO;2","DOIUrl":"https://doi.org/10.2193/0084-0173(2004)155[1:EOSNAP]2.0.CO;2","url":null,"abstract":"<p><b>Abstract: </b> Recent declines in numbers and juvenile recruitment in many elk (<i>Cervus elaphus</i>) herds in the western U.S. has sparked interest in factors that may cause these declines. Inadequate nutrition or delayed parturition, the latter of which may be caused by inadequate numbers of mature bulls (i.e., highly skewed sex ratios), may have separate or synergistic effects on population dynamics and productivity. We evaluated the implications of late parturition and summer-autumn nutrition on reproduction and survival of Rocky Mountain elk (<i>C. e. nelsoni</i>) using a captive herd of 57 cow elk.</p><p>We induced early (Sep) and late breeding (Oct) and 3 levels of summer-autumn nutrition on the cows. Food was offered ad libitum at 3 levels of digestible energy (DE): high = 2.9-3.0 kcal of DE/g of diets, medium = 2.6-3.0 kcal/g, and low = 2.3-3.0 kcal/g. Within these ranges, DE content was gradually reduced from late June through early November to mimic seasonal changes in the wild. During summer and autumn, we measured calf growth; body mass, nutritional condition, and breeding dynamics of cows; and growth and pregnancy of yearlings. We also measured carry-over (i.e., time-lag) responses including over-winter calf and cow survival and parturition date and birth mass, as functions of previous summer-autumn nutrition and previous parturition date. Between autumn 1995 and spring 1998, we conducted 2 years of parturition-date, summer-autumn nutrition experiments, 2 winters of calf survival experiments, and 1 winter of cow survival experiments.</p><p>Early birth provided calves with more time to grow before onset of winter. This “head-start” advantage was maintained through late autumn, but its magnitude was diluted in some instances due to faster growth of some late-born calves. Body mass, body fat, and timing and probability of conception by cows in autumn were little influenced by parturition date the previous spring.</p><p>Summer-autumn nutrition significantly affected calves and their mothers. Growth of calves in the low and medium nutrition groups ceased by mid-September and late October. By December, calves in the high nutrition group were 40% and 70% heavier than calves in the medium and low groups, respectively. Cows in the high nutrition group accumulated about 75% and 300% more fat than cows in the medium and low groups by mid-October. Eighty percent of cows in the low nutrition group failed to conceive, and those in the medium group bred 10–14 days later than cows in the high group. Summer-autumn nutrition of calves influenced their probability of becoming pregnant as yearlings. Probability of pregnancy approached 100% for those yearlings that had high summerautumn nutrition as calves and yearlings, despite near starvation their first winter of life.</p><p>Winter survival of calves was related to their size at the onset of winter. Smaller calves lost more body mass daily than did large calves, and thus they survived fewer da","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"155 1","pages":"1-61"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/0084-0173(2004)155[1:EOSNAP]2.0.CO;2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6218752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population Dynamics of Greater Scaup Breeding on the Yukon-Kuskokwim Delta, Alaska","authors":"PAUL L. FLINT, J. BARRY GRAND, THOMAS F. FONDELL, JULIE A. MORSE","doi":"10.2193/0084-0173(2006)162[1:PDOGSB]2.0.CO;2","DOIUrl":"https://doi.org/10.2193/0084-0173(2006)162[1:PDOGSB]2.0.CO;2","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> ABSTRACT</h3>\u0000 \u0000 <p>Populations of greater scaup (<i>Aythya marila</i>) remained relatively stable during a period when populations of lesser scaup (<i>A. affinis</i>) have declined from historic levels. To assist in describing these differences in population trends, from 1991 through 2000, we studied the survival, nesting ecology, and productivity of greater scaup on the Yukon-Kuskokwim Delta (Y-K Delta), Alaska, to develop a model of population dynamics. We located nests, radio-marked females for renesting studies, estimated duckling survival, and leg-banded females to examine nest site fidelity and annual survival.</p>\u0000 \u0000 <p>Greater scaup initiated egg laying later than other species, and most clutches (>80%) were initiated over 20 days each year. We located 1,056 nests; nest success ranged from 7 to 61 % among years. Following loss of their first clutch, 51 % of radio-tagged females attempted to renest. Duckling survival to 30 days of age was 37.5%. Our best model suggested that annual survival did not vary among years and averaged 81 %. Survival rate was positively related to structural body size. Only 8 of 214 banded individuals were reported as recovered (1 each in Maryland, Michigan, Minnesota, Washington, and Alaska and 3 in California).</p>\u0000 \u0000 <p>Using a stochastic model, we estimated that, on average, breeding females produced 0.57 young females/nesting season. We combined this estimate of productivity with our annual estimates of adult survival and an assumed population growth rate of 1.0, then solved for an estimate of first-year survival (0.40). Under these conditions the predicted stable age distribution of breeding females (i.e., the nesting population) was 15.1% 1-year-old, 4.1% 2-year-old first-time breeders, and 80.8% 2-year-old and older, experienced breeders. We subjected this stochastic model to perturbation analyses to examine the relative effects of demographic parameters on k. The relative effects of productivity and adult survival on the population growth rate were 0.26 and 0.72, respectively. Thus, compared to productivity, proportionally equivalent changes in annual survival would have 2.8 times the effect on k. However, when we examined annual variation in predicted population size using standardized regression coefficients, productivity explained twice as much variation as annual survival. Thus, management actions focused on changes in survival or productivity have the ability to influence population size; however, substantially larger changes in productivity are required to influence population trends.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> RESUMEN</h3>\u0000 \u0000 <p>Poblaciones de pato-boludo mayor (<i>Aythya marila</i>) se quedó relativamente fijo durante un período cuando poblaciones de pato-boludo menor (<i>A. affinis</i","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"162 1","pages":"1-22"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/0084-0173(2006)162[1:PDOGSB]2.0.CO;2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6218768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Herbivore Optimization by North American Elk: Consequences for Theory and Management","authors":"KELLEY M. STEWART, R. TERRY BOWYER, ROGER W. RUESS, BRIAN L. DICK, JOHN G. KIE","doi":"10.2193/0084-0173(2006)167[1:HOBNAE]2.0.CO;2","DOIUrl":"https://doi.org/10.2193/0084-0173(2006)167[1:HOBNAE]2.0.CO;2","url":null,"abstract":"<div>\u0000 \u0000 <section>\u0000 \u0000 <h3> ABSTRACT</h3>\u0000 \u0000 <p>Understanding herbivore optimization has implications for theories underpinning ecosystem processes, management of large herbivores, and the landscapes they inhabit. We designed an experiment to examine interactions related to density dependence of North American elk (<i>Cervus elaphus</i>) and resulting plant responses to herbivory in the Blue Mountains of Oregon, USA, from 1999 to 2001. We experimentally created high (20.1 elk/km<sup>2</sup>) and low (4.1 elk/km<sup>2</sup>) population densities of elk and built exclosures to examine effects of herbivory on productivity and species composition of plants. We hypothesized that if herbivore optimization occurred with increasing density of elk, there should be a concordant increase in plant production, followed by a decline in productivity as grazing intensity continued to increase (i.e., herbivore optimization). Net aboveground primary productivity (NAPP) increased from no herbivory to herbivory by elk at moderate density and then declined as herbivory by elk continued to increase in areas with high NAPP (mesic and logged forests) but not in areas with low NAPP (xeric forests and grasslands). Herbivore optimization occurred across all functional groups of plants, including graminoids, forbs, and shrubs for high-NAPP areas. Herbivore optimization may be difficult to detect in woody plants compared with graminoids because of their differing structure and growth forms. Although herbivore optimization previously has been reported in grasslands, our study documents this phenomenon in woody plant communities. We hypothesize that such subtle changes in NAPP from herbivory might be more common than previously thought; carefully designed experiments are required to detect those responses to herbivory by large herbivores. Apparent offtake of plants followed a similar pattern to NAPP and was greatest at intermediate levels of herbivory by elk, and then declined as NAPP approached zero. Quality of plants, as indexed by percent nitrogen (N), also exhibited a parabolic function with increasing density of elk. Nonetheless, we observed no changes in species composition or diversity of plants with our density manipulations of elk, probably because of the extensive history of grazing by native and domestic herbivores in the Blue Mountains, the resilience of the remaining plants to herbivory, and the short 3-year duration of our study. Likewise, we observed no increases in rates of nutrient cycling with changes in densities of elk, perhaps because areas where large amounts of elk urine and feces were concentrated (e.g., grazing lawns) did not occur in this ecosystem.</p>\u0000 \u0000 <p>Herbivore optimization could have ramifications for population dynamics of ungulates. We argue that other processes, such as migration, predation, or harvest, might be necessary to maintain areas of increased NAPP be","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"167 1","pages":"1-24"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/0084-0173(2006)167[1:HOBNAE]2.0.CO;2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6207307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population Dynamics and Harvest Characteristics of Wolves in the Central Brooks Range, Alaska","authors":"LAYNE G. ADAMS, ROBERT O. STEPHENSON, BRUCE W. DALE, ROBERT T. AHGOOK, DOMINIC J. DEMMA","doi":"10.2193/2008-012","DOIUrl":"https://doi.org/10.2193/2008-012","url":null,"abstract":"<p><b>ABSTRACT </b> Our understanding of wolf (<i>Canis lupus</i>) population dynamics in North America comes largely from studies of protected areas, at-risk populations, and wolf control programs, although most North American wolves experience moderate levels of regulated harvest. During 1986–1992, we investigated the population dynamics and harvests of wolves in the newly created Gates of the Arctic National Park and Preserve in northern Alaska, USA, where wolves were harvested by local residents. Our objectives were to determine wolf abundance, estimate important vital rates (i.e., productivity, survival, emigration), and characterize wolf harvests. We monitored 50 radiocollared wolves in 25 packs over 4 years (Apr 1987–Apr 1991) to assess patterns of dispersal, emigration, survival and mortality causes in the wolf population. We determined pack sizes, home ranges, and pups per pack in autumn (1 Oct) for instrumented wolf packs, and calculated wolf densities in autumn and spring (15 Apr) based on the number of wolves in instrumented packs and the aggregate area those packs inhabited. We also gathered information from local hunters and trappers on the timing, location, methods, and sex-age composition of wolf harvests during 6 winter harvest seasons (Aug 1987–Apr 1992).</p><p>Wolf densities averaged 6.6 wolves per 1,000 km<sup>2</sup> and 4.5 wolves per 1,000 km<sup>2</sup> in autumn and spring, respectively, and spring densities increased by 5% per year during our study. On average, pups constituted 50% of the resident wolf population each autumn. An estimated 12% of the population was harvested annually. Natural mortality, primarily intraspecific strife, equaled 11% per year. Young wolves emigrated from the study area at high annual rates (47% and 27% for yearlings and 2-yr-olds, respectively), and we estimated the emigration rate for the population at ≥19% annually. Yearlings and 2-year-olds were lost from the population at rates of 60% per year and 45% per year, respectively, primarily as a result of emigration; mortality was the principal cause of the 26% annual loss of wolves ≥3 years old.</p><p>On average, 47 wolves were harvested each winter from our study population, or twice the harvest we estimated from survival analyses of radiocollared wolves (23 wolves/yr). We suggest that the additional harvested wolves were transients, including local dispersers and migrants from outside the study area. Trapping harvest was well-distributed throughout the trapping season (Nov-Apr), whereas shooting harvest occurred mainly in February and March. Of 35 individuals who harvested wolves in the area, 6 accounted for 66% of the harvest.</p><p>We analyzed information from North American wolf populations and determined that annual rates of increase have an inverse, curvilinear relationship with human-caused mortality (<i>r</i><sup>2</sup> = 0.68, <i>P</i> < 0.001) such that population trends were not correlated with annual human take ≤29% (<i>P</i> ","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":"170 1","pages":"1-25"},"PeriodicalIF":4.4,"publicationDate":"2010-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2193/2008-012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6207314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}