| 1. |
- Ekblom, Robert, Docent, 1976-, et al.
(författare)
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Sample identification and pedigree reconstruction in Wolverine (Gulo gulo) using SNP genotyping of non-invasive samples
- 2021
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Ingår i: Conservation Genetics Resources. - : Springer Nature. - 1877-7252 .- 1877-7260. ; 13:3, s. 261-274
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Tidskriftsartikel (refereegranskat)abstract
- For conservation genetic studies using non-invasively collected samples, genome-wide data may be hard to acquire. Until now, such studies have instead mostly relied on analyses of traditional genetic markers such as microsatellites (SSRs). Recently, high throughput genotyping of single nucleotide polymorphisms (SNPs) has become available, expanding the use of genomic methods to include non-model species of conservation concern. We have developed a 96-marker SNP array for use in applied conservation monitoring of the Scandinavian wolverine (Gulo gulo) population. By genotyping more than a thousand non-invasively collected samples, we were able to obtain precise estimates of different types of genotyping errors and sample dropout rates. The SNP panel significantly outperforms the SSR markers (and DBY intron markers for sexing) both in terms of precision in genotyping, sex assignment and individual identification, as well as in the proportion of samples successfully genotyped. Furthermore, SNP genotyping offers a simplified laboratory and analysis pipeline with fewer samples needed to be repeatedly genotyped in order to obtain reliable consensus data. In addition, we utilised a unique opportunity to successfully demonstrate the application of SNP genotype data for reconstructing pedigrees in wild populations, by validating the method with samples from wild individuals with known relatedness. By offering a simplified workflow with improved performance, we anticipate this methodology will facilitate the use of non-invasive samples to improve genetic management of many different types of populations that have previously been challenging to survey.
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| 2. |
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| 3. |
- Andrén, Henrik, et al.
(författare)
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Harvest models of small populations of a large carnivore using Bayesian forecasting
- 2020
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Ingår i: Ecological Applications. - : Wiley. - 1051-0761 .- 1939-5582. ; 30:3
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Tidskriftsartikel (refereegranskat)abstract
- Harvesting large carnivores can be a management tool for meeting politically set goals for their desired abundance. However, harvesting carnivores creates its own set of conflicts in both society and among conservation professionals, where one consequence is a need to demonstrate that management is sustainable, evidence-based, and guided by science. Furthermore, because large carnivores often also have high degrees of legal protection, harvest quotas have to be carefully justified and constantly adjusted to avoid damaging their conservation status. We developed a Bayesian state-space model to support adaptive management of Eurasian lynx harvesting in Scandinavia. The model uses data from the annual monitoring of lynx abundance and results from long-term field research on lynx biology, which has provided detailed estimates of key demographic parameters. We used the model to predict the probability that the forecasted population size will be below or above the management objectives when subjected to different harvest quotas. The model presented here informs decision makers about the policy risks of alternative harvest levels. Earlier versions of the model have been available for wildlife managers in both Sweden and Norway to guide lynx harvest quotas and the model predictions showed good agreement with observations. We combined monitoring data with data on vital rates and were able to estimate unobserved additional mortality rates, which are most probably due to poaching. In both countries, the past quota setting strategy suggests that there has been a de facto threshold strategy with increasing proportion, which means that there is no harvest below a certain population size, but above this threshold there is an increasing proportion of the population harvested as the population size increases. The annual assessment of the monitoring results, the use of forecasting models, and a threshold harvest approach to quota setting will all reduce the risk of lynx population sizes moving outside the desired goals. The approach we illustrate could be adapted to other populations of mammals worldwide.
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| 4. |
- Andren, Henrik, et al.
(författare)
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No Allee effect detected during the natural recolonization by a large carnivore despite low growth rate
- 2022
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Ingår i: Ecosphere. - : Wiley. - 2150-8925 .- 2150-8925. ; 13:3
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Tidskriftsartikel (refereegranskat)abstract
- Eurasian lynx (Lynx lynx) have recently naturally recolonized southern Sweden. The first documented reproduction of lynx in recent times occurred in 2003, and the population increased from 2 to 48 family groups (the unit of measurement in Swedish monitoring) during its first 18 years (2003/2004–2020/2021). We did not detect any Allee effect, that is, lower growth rate at low population density, during the recolonization of southern Sweden, although our population simulations revealed a non-negligible (30%) chance that population observed development could include an Allee effect. The probable absence of an Allee effect was likely because colonizing females did not lack mating partners, as a larger number of wide-ranging males were established in the area before documented reproduction took place. Despite the absence of an Allee effect, the growth rate during recolonization was lower in southern Sweden (λ = 1.20) than in central Sweden (λ = 1.29). We have no evidence of higher mortality, including that from poaching, or lower reproduction in southern Sweden could explain the lower growth rate. Instead, we suggest that the lower growth rate during the recolonization of southern Sweden was explained by fewer immigrants arriving from central Sweden due to areas of less suitable habitat between central and southern Sweden, partially preventing immigration southward. From a conservation point of view, it is positive that this small population could recover without being negatively influenced by an Allee effect, as small populations with an Allee effect experience lower viability than those without.
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| 5. |
- Andren, Henrik, et al.
(författare)
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Season rather than habitat affects lynx survival and risk of mortality in the human-dominated landscape of southern Sweden
- 2022
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Ingår i: Wildlife Biology. - : Wiley. - 0909-6396 .- 1903-220X. ; 2022
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Tidskriftsartikel (refereegranskat)abstract
- Landscapes are mosaics of habitat associated with different risks and resources, including human activities, which can affect individual survival in wildlife. Different relationships between habitat characteristics and human-caused and natural mortality can result in attractive sinks. We used individual-based data from 97 Eurasian lynx Lynx lynx monitored for 160 exposure-years to link adult survival and the risk of mortality to home range habitat characteristics in the human-dominated landscape of southern Sweden. Human-caused mortality (i.e. legal hunting, poaching and vehicle accidents) dominated mortality causes (24 out of 37 deaths). We did not detect any strong effects of habitat characterises explaining the variation in mortality risk in lynx. Although the density of roe deer affects several aspects of lynx ecology, we could not detect any effects of roe deer density on lynx survival, probably because roe deer density was sufficiently high in our study area. Instead, seasonal variation was the main factor influencing mortality in lynx. Mortality was highest during the hunting season for lynx (16 February-31 March), as well as during autumn and winter, probably because lynx poaching occurs opportunistically during the hunting season for moose and roe deer. We did not find any indication that human activity created attractive sinks for lynx, since there were no contrasting patterns between human-caused and natural mortality in terms of habitat characteristics. One explanation for the limited influence of the home range characteristics may be that lynx in our study died from multiple causes. Therefore, it is less likely that one or a few habitat characteristics could explain the risk of mortality at the home range scale. There is strong evidence that lynx can coexist with humans in multi-use and human-dominated landscapes, even without large protected areas, if the management regimes are favourable.
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| 6. |
- Aronsson, Helena, et al.
(författare)
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Phosphorus load in outdoor areas for laying hens and capacity of phosphorus retaining materials to reduce the environmental impact
- 2022
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Ingår i: Organic Agriculture. - : Springer Science and Business Media B.V.. - 1879-4238 .- 1879-4246. ; 12:3, s. 325-
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated manure loads in outdoor paddocks for laying hens and the capacity of two phosphorus (P) retaining materials for reducing leaching from manure in areas with high hen density. Inventories on two commercial farms during 2 years (2017 and 2018) of the impact of hens (groups of 3000 hens) on vegetation, as a proxy for land use by hens, showed that 16–21% of outdoor area in grassland paddocks and 22–39% of area in a forest paddock were used by the hens. Sand and limestone were tested as P retention materials in areas with high manure load in a field study during the outdoor season for laying hens (May 1 to October 31 in 2018). The materials were placed on the ground (0.2 m deep bed, 3.3 m wide) outside the pop-hole in paddocks with 76 hens. The average numbers of hens outdoors were recorded at 9 am and 3 pm daily. There was no significant difference between the materials concerning distribution of hens, and they seemed not to prefer any material more than the other. When cylinders containing the spent materials were exposed to simulated rainfalls in a laboratory study, the P concentrations in drainage water were high for all materials, including a control with gravel (58–136 mg PO4-P L−1 and 130–197 mg total-P L−1). On average, 14% of manure P retained in the sand and limestone materials was leached after 100 mm of simulated rainfall. Thus, these materials may act as physical filters for P in manure, but to reduce the risk of P losses to waters during the following winter, they need to be removed from the paddocks and preferably used as potential P fertilizers on arable land. © 2021, The Author(s).
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| 7. |
- Aronsson, Malin, et al.
(författare)
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Användning av kamerastationer för järv : individbestämning, könsbestämning samt förekomst av lakterande honor
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Kamerastationerna fungerar bra för att fotografera järv, majoriteten av alla bilder från kamerastationerna vi använt har varit av järv. Det kan däremot ta ett tag innan järven börjar använda kamerastationen. Bilderna från kamerastationerna har fungerat bra för att könsbestämma järvarna samt se om honor är lakterande. Det har i viss mån även gått att identifiera olika järvindivider genom att titta på teckning på bröstet. Det är viktigt att betet sitter så högt att järven behöver använda klätterstödet med bakbenen för att den ska gå att könsbestämma. Kamerastationen bör sitta 1.5-2.5 m över marken/snötäcket för att minimera bilder på andra djur. Vi har använt både sågat virke och bakar till kamerastationen och båda verkar fungera lika bra. Vid kamerastationerna har vi använt två kameror, en fäst vid ett träd mitt emot ställningen (kamera 1) som fotograferar ett område från överdelen av plattformen till nederdelen av betet och en som fotograferar hela kamerastationen (kamera 2). Det är viktigt att kamera 1 tar bilder av bra kvalitet och att rörelsesensorn utlöses snabbt vid rörelse på stationen. Vid placering av kamerastationen tänk på att motljus, drevsnö, grenar som rör sig i vinden försämrar bilderna och ökar risken för ”tomma bilder”. Mycket fukt i luften eller att solen står lågt är andra faktorer som påverkar bildkvalitén men som är svåra att komma ifrån. På våra kamerastationer i Dalarna har kontrasten i framförallt nattbilder försämrats avsevärt av att klätterstöden var för ljusa. Vi har provat att beta kamerastationer med både kött och doftmedel. För att järven ska hitta kamerastationen är det bra att använda bete med stark doft och järvarna verkar gilla bäver. I början kan bete också sättas högre upp i angränsande träd för att öka doftspridning samt läggas löst på plattformen så att järven motiveras att klättra upp. Betet ovanför kamerastationen måste sitta så högt att järven måste använda klätterstödet med bakbenen, men inte så högt att järven ger upp eller försöker nå det på annat sätt, vi rekommenderar att sätta betet 40-60 cm ovanför klätterstödet. Betet måste sitta ordentligt fast så att järven inte kan dra ner allt direkt. Vi ser flera potentiella användningsområden för kamerastationer i dagens inventering, framförallt i södra delen av järvens utbredningsområde med begränsade förutsättningar för snöspårning. Kamerastationerna kan användas för att dokumentera förekomst av järv, könsbestämning, val av områden för riktade insatser att hitta lyor utifrån foton av honor samt dokumentation av lakterande honor. Järvprojektet planerar att arbeta vidare med en eventuell användning av kamerastationer för att dokumentera föryngring av järv på ett kostnads- och tidseffektivt sätt som minskar störningen vid lyplatser. Kamerastationen skulle även kunna användas för insamling av hår för DNA-analys som tillsammans med bilderna kan identifiera järvindivider för lokala populationsuppskattningar med fångst-återfångst beräkningar. Slutligen så vill vi poängtera vikten av att hela järvens utbredning inventeras eftersom både mål för populationsstorlek och förvaltningsbeslut bygger på den totala populationsstorleken. Antalet järvar utanför renskötselområdet ha stor påverkan på utrymmet för förvaltningsåtgärder inom renskötselområdet.
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| 8. |
- Aronsson, Malin, et al.
(författare)
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Avstandskriterier for beregning av antall jerveynglinger : en evaluering av avstand mellom yngleobservasjoner uten tilknytting til hiplass
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Bestandsstørrelse og bestandsutvikling hos jerv i Skandinavia overvåkes gjennom registrering av antall ynglinger og ved hjelp av DNA. I overvåkingen av ynglinger er det viktig å kunne vurdere om observasjoner av yngleaktivitet er fra den samme jervetispa eller fra to ulike tisper. I dagens overvåkingsinstruks finnes det ingen avstandskriterier (AK) for å skille mellom to ulike observasjoner av yngleaktivitet der ingen av observasjonene er knyttet til en hiplass, dvs. observasjoner av lakterende tisper, og spor- eller synsobservasjoner av jervevalper. AK på 10 km mellom hiplasser blir derfor brukt. Målet med denne rapporten er å analysere forflytningsmønsteret hos GPS merkete ynglende jervetisper og undersøke sannsynligheten for at to posisjoner tilhører den samme jervetispa vs. sannsynligheten for at de to posisjonene tilhører to forskjellige jervetisper ved forskjellige statiske AK. Vi har all brukt alle tilgjengelige GPS data på jerv fra Skandinavia, både fra barskog og fjellområder.Distansene mellom to daglige posisjoner for den samme tispa (forflyttingsdistanse) varierte ikke mye med antall dager mellom posisjonene (1-150 dager). Når tidsdifferanse ble begrenset til < 15 dager, var distansene større tidlig i februar og sank mot første halvdel av mars, grunnet jervetispas tilknytning til hiet, før de igjen steg utover våren og var stabile utover sommeren. Det var en tydelig sammenheng mellom størrelsen på hjemmeområde og distansen som en tispe beveger seg, men det var ikke noen tydelig relasjon mellom andelen skog eller fjell i hjemmeområdet og størrelsen på hjemmeområdet eller forflyttingsdistansene. Ved dagens AK på 10 km var det 36 % sannsynlighet at to posisjoner kom fra to ulike jervetisper med én dag mellom posisjonene og 46 % med 150 dager mellom posisjonene. Samtidig var 21 % av distansene mellom to daglige posisjoner for samme tispe over 10 km.Når et AK skal fastsettes er det to typer feil vi ønsker å unngå; feilaktig slå sammen to observasjoner av ulike ynglende jervetisper til én yngling (underestimere) og feilaktig splitte to observasjoner av den samme ynglende jervetispa til to ulike observasjoner (overestimere). Intet AK vil være feilfritt og vil kunne inkludere en risiko for overestimering og/eller underestimering. Hvilket AK man velger er avhengig av hvordan risikoen for overestimering og underestimering av antall ynglinger vektlegges. Vår vurdering er at et AK på rundt 15 km mellom to observasjoner som ikke er knyttet til en hiplass vil være et konservativt avstandskriterium som balanserer risikoen for over eller underestimering av antall ynglinger. Sannsynligheten for at to posisjoner fra den samme jervetispa er lenger enn 15 km er liten (0,03) selv om over 80 % av de ynglende jervetispene hadde forflyttingsdistanser som var lengre enn 15 km. Samtidig er det mest sannsynlig at to posisjoner 15 km i fra hverandre tilhører to ulike jervetisper (73-79%). Vi argumenterer for at et AK på 10km har for stor risiko for å overestimere antall ynglinger og at et AK på 20 km har for stor risiko for å underestimere antall ynglinger.
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| 9. |
- Aronsson, Malin, et al.
(författare)
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Female breeding dispersal in wolverines, a solitary carnivore with high territorial fidelity
- 2018
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Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 64
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Tidskriftsartikel (refereegranskat)abstract
- Individuals' fidelity to an area provides insight into the stability of the spatial and temporal organisation of animals. Territorial fidelity is often influenced by reproductive success, age, the dispersion and predictability of resources, and intraspecific competition. We examined between-year territorial fidelity in wolverines (Gulo gulo), using location data from 47 individuals collected during 1993-2013 in northern Sweden, to assess the stability of the spatial organisation of this solitary carnivore. For females, we also determined residency status from 1 year to the next. The study population is characterized by a stable distribution of resident individuals, with both males and females showing higher fidelity at the total territory level compared to more intensively used core areas. In 86% of the yearly residency status estimates (n = 122), the female remained stationary. In the remaining 14% of the cases, females either vacated their territory (8% of residency statuses), or expanded into a neighbouring territory (6% of residency statuses). We documented six cases of breeding dispersal, representing one of the few known cases of breeding dispersal in longlived large mammals. We suggest that this high territorial fidelity is enabled by wolverines' caching and scavenging behaviours, which buffer the unpredictable and large spatiotemporal variation in resource abundance in this low-productivity area. Breeding dispersal may occur due to competition for high-quality territories in this saturated population, where females are forced to abandon their territory by competitors or bequeath territories to offspring. This study further highlights the complexity of the social and spatial dynamics for solitary carnivores.
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| 10. |
- Aronsson, Malin, et al.
(författare)
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Intensity of space use reveals conditional sex-specific effects of prey and conspecific density on home range size
- 2016
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 6, s. 2957-2967
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Tidskriftsartikel (refereegranskat)abstract
- Home range (HR) size variation is often linked to resource abundance, with sex differences expected to relate to sex-specific fitness consequences. However, studies generally fail to disentangle the effects of the two main drivers of HR size variation, food and conspecific density, and rarely consider how their relative influence change over spatiotemporal scales. We used location data from 77 Eurasian lynx (Lynx lynx) from a 16-year Scandinavian study to examine HR sizes variation relative to prey and conspecific density at different spatiotemporal scales. By varying the isopleth parameter (intensity of use) defining the HR, we show that sex-specific effects were conditional on the spatial scale considered. Males had larger HRs than females in all seasons. Females' total HR size declined as prey and conspecific density increased, whereas males' total HR was only affected by conspecific density. However, as the intensity of use within the HR increased (from 90% to 50% isopleth), the relationship between prey density and area showed opposing patterns for females and males; for females, the prey density effect was reduced, while for males, prey became increasingly important. Thus, prey influenced the size of key regions within male HRs, despite total HR size being independent of prey density. Males reduced their HR size during the mating season, likely to remain close to individual females in estrous. Females reduced their HR size postreproduction probably because of movement constrains imposed by dependent young. Our findings highlight the importance of simultaneously considering resources and intraspecific interactions as HR size determinants. We show that sex-specific demands influence the importance of prey and conspecific density on space use at different spatiotemporal scales. Thus, unless a gradient of space use intensity is examined, factors not related to total HR size might be disregarded despite their importance in determining size of key regions within the HR.
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