Caribou (Rangifer tarandus granti) calf:cow ratios (CCR) computed from composition counts obtained on arctic calving grounds are biased estimators of net calf production (NCP, the product of parturition rate and early calf survival) for sexually-mature females. Sexually-immature 2-year-old females, which are indistinguishable from sexually-mature females without calves, are included in the denominator, thereby biasing the calculated ratio low. This underestimate increases with the proportion of 2-year-old females in the population. We estimated the magnitude of this error with deterministic simulations under three scenarios of calf and yearling annual survival (respectively: low, 60 and 70%; medium, 70 and 80%; high, 80 and 90%) for five levels of unbiased NCP: 20, 40, 60, 80, and 100%. We assumed a survival rate of 90% for both 2-year-old and mature females. For each NCP, we computed numbers of 2-year-old females surviving annually and increased the denominator of CCR accordingly. We then calculated a series of hypothetical “observed” CCRs, which stabilized during the last 6 years of the simulations, and documented the degree to which each 6-year mean CCR differed from the corresponding NCP. For the three calf and yearling survival scenarios, proportional underestimates of NCP by CCR ranged 0.046–0.156, 0.058–0.187, and 0.071–0.216, respectively. Unfortunately, because parturition and survival rates are typically variable (i.e., age distribution is unstable), the magnitude of the error is not predictable without substantial supporting information. We recommend maintaining a sufficient sample of known-age radiocollared females in each herd and implementing a regular relocation schedule during the calving period to obtain unbiased estimates of both parturition rate and NCP.
{"title":"Efficacy of calf:cow ratios for estimating calf production of arctic caribou","authors":"R. Cameron, B. Griffith, L. S. Parrett, R. White","doi":"10.7557/2.33.2.2527","DOIUrl":"https://doi.org/10.7557/2.33.2.2527","url":null,"abstract":"Caribou (Rangifer tarandus granti) calf:cow ratios (CCR) computed from composition counts obtained on arctic calving grounds are biased estimators of net calf production (NCP, the product of parturition rate and early calf survival) for sexually-mature females. Sexually-immature 2-year-old females, which are indistinguishable from sexually-mature females without calves, are included in the denominator, thereby biasing the calculated ratio low. This underestimate increases with the proportion of 2-year-old females in the population. We estimated the magnitude of this error with deterministic simulations under three scenarios of calf and yearling annual survival (respectively: low, 60 and 70%; medium, 70 and 80%; high, 80 and 90%) for five levels of unbiased NCP: 20, 40, 60, 80, and 100%. We assumed a survival rate of 90% for both 2-year-old and mature females. For each NCP, we computed numbers of 2-year-old females surviving annually and increased the denominator of CCR accordingly. We then calculated a series of hypothetical “observed” CCRs, which stabilized during the last 6 years of the simulations, and documented the degree to which each 6-year mean CCR differed from the corresponding NCP. For the three calf and yearling survival scenarios, proportional underestimates of NCP by CCR ranged 0.046–0.156, 0.058–0.187, and 0.071–0.216, respectively. Unfortunately, because parturition and survival rates are typically variable (i.e., age distribution is unstable), the magnitude of the error is not predictable without substantial supporting information. We recommend maintaining a sufficient sample of known-age radiocollared females in each herd and implementing a regular relocation schedule during the calving period to obtain unbiased estimates of both parturition rate and NCP.","PeriodicalId":30034,"journal":{"name":"Rangifer","volume":"33 1","pages":"27-34"},"PeriodicalIF":0.0,"publicationDate":"2013-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71330516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarskils uppmarksamhet fasts vid sambandet mellan vinterkatastrofer och betesmarkernas situation, katastrofernas inverkan pa renens populationsdynamik samt de metoder som anvands for att forebygga katatrofer.
{"title":"Vinterkatastrofer inom renskötseln i Finland: Förluster och deras forebyggande","authors":"Timo Helle","doi":"10.7557/2.2.1-APP.437","DOIUrl":"https://doi.org/10.7557/2.2.1-APP.437","url":null,"abstract":"Sarskils uppmarksamhet fasts vid sambandet mellan vinterkatastrofer och betesmarkernas situation, katastrofernas inverkan pa renens populationsdynamik samt de metoder som anvands for att forebygga katatrofer.","PeriodicalId":30034,"journal":{"name":"Rangifer","volume":"2 1","pages":"3-4"},"PeriodicalIF":0.0,"publicationDate":"2013-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71325379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I Norge har det vaert laget offentlige utredninger om reindriften de siste 100 ar, og av naersagt alle gar det fram at risikoen for tap er store. Vi vet at tapene er store nar forholdene er ugunstige, fremdeles kan vi gjore lite for a hindre det, og fremdeles har vi problemer med a dokumentere dem.
{"title":"Oversikt over tapene i Norge","authors":"Ansgar Kosmo","doi":"10.7557/2.2.1-APP.438","DOIUrl":"https://doi.org/10.7557/2.2.1-APP.438","url":null,"abstract":"I Norge har det vaert laget offentlige utredninger om reindriften de siste 100 ar, og av naersagt alle gar det fram at risikoen for tap er store. Vi vet at tapene er store nar forholdene er ugunstige, fremdeles kan vi gjore lite for a hindre det, og fremdeles har vi problemer med a dokumentere dem.","PeriodicalId":30034,"journal":{"name":"Rangifer","volume":"2 1","pages":"5-16"},"PeriodicalIF":0.0,"publicationDate":"2013-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71325484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lederen av Statens veterinaere laboratorium for Nord-Norge gjennomgar aktuell statistikk med utgangspunt i forholdene i Vest-Finnmark som han kjenner best.
挪威北部国家兽医实验室负责人正在根据他最了解的西芬马克的关系进行最新统计。
{"title":"Sykdommer som tapsfaktorer innen reindriften","authors":"Knut Kummeneje","doi":"10.7557/2.2.1-APP.441","DOIUrl":"https://doi.org/10.7557/2.2.1-APP.441","url":null,"abstract":"Lederen av Statens veterinaere laboratorium for Nord-Norge gjennomgar aktuell statistikk med utgangspunt i forholdene i Vest-Finnmark som han kjenner best.","PeriodicalId":30034,"journal":{"name":"Rangifer","volume":"2 1","pages":"36-46"},"PeriodicalIF":0.0,"publicationDate":"2013-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71325505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tabellene og diagrammene er sammenstillinger av tilgjengelig materiale fra flere statlige kilder samt fra forsikringsselskapenes opplysningstjeneste.
这些表格和图表是由几个政府来源的可用材料以及保险公司的信息服务组成的。
{"title":"Renförluster i Sverige. Statistik och ersättningsmetodik","authors":"Hans Korak","doi":"10.7557/2.2.1-APP.439","DOIUrl":"https://doi.org/10.7557/2.2.1-APP.439","url":null,"abstract":"Tabellene og diagrammene er sammenstillinger av tilgjengelig materiale fra flere statlige kilder samt fra forsikringsselskapenes opplysningstjeneste.","PeriodicalId":30034,"journal":{"name":"Rangifer","volume":"2 1","pages":"17-27"},"PeriodicalIF":0.0,"publicationDate":"2013-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71325494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Birgitta Ahman is the photographer of the series of pictures from the conference, also for the cover photo of the full paper edition showing Kongsvold Mountain Hut and Biological Station.
{"title":"Photos of the conference","authors":"B. Åhman","doi":"10.7557/2.2.1-APP.460","DOIUrl":"https://doi.org/10.7557/2.2.1-APP.460","url":null,"abstract":"Birgitta Ahman is the photographer of the series of pictures from the conference, also for the cover photo of the full paper edition showing Kongsvold Mountain Hut and Biological Station.","PeriodicalId":30034,"journal":{"name":"Rangifer","volume":"2 1","pages":"128-132"},"PeriodicalIF":0.0,"publicationDate":"2013-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71325917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fra de nordiske landene deltok det 30 personer tilknyttet forskning, forvaltning, administrasjon og reindriften.
来自北欧国家的30人参与了研究、管理、行政管理和驯鹿饲养。
{"title":"Deltakerliste - List of participants","authors":"S. Skjenneberg","doi":"10.7557/2.2.1-APP.459","DOIUrl":"https://doi.org/10.7557/2.2.1-APP.459","url":null,"abstract":"Fra de nordiske landene deltok det 30 personer tilknyttet forskning, forvaltning, administrasjon og reindriften.","PeriodicalId":30034,"journal":{"name":"Rangifer","volume":"2 1","pages":"125-127"},"PeriodicalIF":0.0,"publicationDate":"2013-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71325907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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