| 1. |
- Andren, Henrik, et al.
(författare)
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Modelling the combined effect of an obligate predator and a facultative predator on a common prey: lynx Lynx lynx and wolverine Gulo gulo predation on reindeer Rangifer tarandus
- 2011
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Ingår i: Wildlife Biology. - : Wiley. - 0909-6396 .- 1903-220X. ; 17, s. 33-43
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Tidskriftsartikel (refereegranskat)abstract
- In conservation and management of large predators, effects of species are often considered separately. However, predators often interact with one another in different ways (e.g. interspecific competition, intra guild predation and kleptoparasitism) that may influence the total predation on a common prey. We estimated the total number of semi-domestic reindeer Rangifer tarandus killed by Eurasian lynx Lynx lynx and wolverine Gulo gulo at different relative abundances of the two species using a model based on diet, food requirements of lynx and wolverine and amount of food available on a reindeer. Our model suggests that total predation decreases by approximately 7.9% (+/- 4.8 SD) if wolverines scavenge on lynx-killed reindeer, compared to a model without scavenging. If the management goal is a constant number of predators, the model suggests that the total kill rate will be lowest in areas with only wolverines, as the estimated wolverine kill rate is much lower than the lynx kill rate. Our model showed that it is unlikely that the lowest number of reindeer killed per predator individual will be at a certain lynx-wolverine ratio, which would appear if lynx consumption of killed reindeer is low and wolverines are very efficient finding lynx-killed reindeer. However, if the management goal is a constant number of lynx and wolverines, the model suggests that the total predation is lower, if lynx and wolverines coexist in the same area compared to existing separately in different areas. The total predation by wolverine and lynx on reindeer is very important for the management of lynx and wolverine in the reindeer husbandry area in Sweden, as the current compensation scheme for predator-killed semi-domestic reindeer is based on the number of predators present within a reindeer herding district, and the compensation for wolverine and lynx is added independently of one another.
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| 2. |
- Broekman, Maarten J. E., et al.
(författare)
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Evaluating expert-based habitat suitability information of terrestrial mammals with GPS-tracking data
- 2022
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 31:8, s. 1526-1541
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Macroecological studies that require habitat suitability data for many species often derive this information from expert opinion. However, expert-based information is inherently subjective and thus prone to errors. The increasing availability of GPS tracking data offers opportunities to evaluate and supplement expert-based information with detailed empirical evidence. Here, we compared expert-based habitat suitability information from the International Union for Conservation of Nature (IUCN) with habitat suitability information derived from GPS-tracking data of 1,498 individuals from 49 mammal species.Location: Worldwide.Time period: 1998-2021.Major taxa studied: Forty-nine terrestrial mammal species.Methods: Using GPS data, we estimated two measures of habitat suitability for each individual animal: proportional habitat use (proportion of GPS locations within a habitat type), and selection ratio (habitat use relative to its availability). For each individual we then evaluated whether the GPS-based habitat suitability measures were in agreement with the IUCN data. To that end, we calculated the probability that the ranking of empirical habitat suitability measures was in agreement with IUCN's classification into suitable, marginal and unsuitable habitat types.Results: IUCN habitat suitability data were in accordance with the GPS data (> 95% probability of agreement) for 33 out of 49 species based on proportional habitat use estimates and for 25 out of 49 species based on selection ratios. In addition, 37 and 34 species had a > 50% probability of agreement based on proportional habitat use and selection ratios, respectively.Main conclusions: We show how GPS-tracking data can be used to evaluate IUCN habitat suitability data. Our findings indicate that for the majority of species included in this study, it is appropriate to use IUCN habitat suitability data in macroecological studies. Furthermore, we show that GPS-tracking data can be used to identify and prioritize species and habitat types for re-evaluation of IUCN habitat suitability data.
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| 3. |
- Chapron, Guillaume, et al.
(författare)
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Restoration of wolverines: Considerations for translocation and post-release monitoring
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Successful reintroduction of wolverines to historically occupied, suitable habitat could function as a major proactive step toward improving wolverine status and genetic diversity in the contiguous United States. However, because wolverine reintroduction has not been previously attempted, there is a need to assemble information to develop the most appropriate techniques in case this management option becomes desirable and politically feasible. In this document we describe pros and cons of various approaches (and identify obvious nonstarters) and advocate an adaptive approach for reintroductions. We find this preferable to a more prescriptive approach because the “right” answer is largely unknown without prior experience. We suggest that ongoing assessment and modification of capture, transport, and care of captive animals is used to ensure the highest probability of survival and site fidelity. Wherever possible, activities should be undertaken in a manner that maximizes the ability to learn from experiences and adapt to improve. Protocols will likely change as more information and experience is accumulated. We suggest sourcing wolverines that maximize genetic diversity of the reintroduced population after consideration of other factors such as the sustainability of removals from source populations and matching habitat and prey between source and relocation sites. A mixture of wolverines from multiple locations including Alaska, British Columbia, Yukon Territory, and Northwest Territory would provide a broad genotypic representation. Additional areas that provide unique genetic material (e.g., Manitoba, Nunavut) could also prove beneficial but would require careful selection due to smaller source populations and differences in habitat/prey/mortality sources. Total numbers translocated from any one site should be carefully considered based on locally available data. Our consensus regarding the number of wolverines to move during an initial translocation was strong for a larger number of individuals over several years (i.e., >10/year for multiple years) rather than a smaller, more conservative number. This approach would protect against stochastic failure and reduce time to reestablishment. To determine season of capture and method of release most likely to be successful, we considered effects that translocation may have on wolverine survival, site fidelity, and reproduction. Consensus formed around winter captures (Oct–Dec) followed by a provisioned release (release into natural snow-covered chambers where supplemental food has been placed) after a short stay at a captive transfer facility. The option of retaining pregnant females at a captive facility until or just prior to parturition (Feb 1 or later if ultrasound or other information is available) may help improve site fidelity. This could be particularly useful if large movements away from the reintroduction site are deemed to be a problem. Because same-year reproductions may occur and are valuable for improving site fidelity, genetic diversity, and successful establishment of a population, careful consideration of how to release males, if at all, is warranted (some species have been reestablished by moving pregnant females and allowing male offspring to mature, disperse, and breed). We provide details of aspects to consider during capture, handling, inspection, and transportation of wolverines. We also briefly discuss monitoring of translocated populations.
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| 4. |
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| 5. |
- Höglund, Linda, et al.
(författare)
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Inventering av järv 2019
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Norwegian Environment Agency (Miljødirektoratet) and the Swedish Environmental Protection Agency (Naturvårdsverket) have co-developed standard methodology and guidelines for the monitoring of wolverines in Scandinavia, that have been implemented in both Norway and Sweden since 2014. To estimate size, and assessing trends, of the wolverine population in Scandinavia, wolverine reproductive areas (female territories) are annually surveyed during late winter and spring to register whether reproductions have occurred. The population size is estimated based on the number of wolverine reproductions that fulfil the criteria for Documented or Considered as certain reproduction. The monitoring of wolverine reproductions, and registration of data into the shared database Rovbase, is conducted by field staff from the County Administration Boards CAB (Länsstyrelserna) in Sweden and the Norwegian Nature Inspectorate (Statens Naturoppsyn) in Norway. In Sweden, the Sami villages (administrative units for reindeer herding) aid the CABs by reporting suspected den sites, which can then be evaluated in the field by CAB field personnel. During the 2019 census a total of 165 wolverine reproductions were registered in Scandinavia, a 9% decrease compared to 2018. Of these, 104 reproductions were found in Sweden and 61 in Norway. This corresponds to a 16% decrease in Sweden and a 5% increase in Norway compared to 2018. The model used to estimate population size, i.e. extrapolate number of reproductions to adult individuals in the population, accounts for annual variation in reproductive success by using the average number of reproductions in the past three years. Based on the number of wolverine reproductions during the last three years (2017–2019), the Scandinavian population size is estimated to 1011 adult wolverines, defined as 1-year old or older (95% CI = 869–1268), which is a higher estimate for Scandinavia than last year. Of the 1011 wolverines, 332 wolverines (95% CI = 273–427) are estimated to be in Norway and 679 wolverines (95% CI = 565–891) in Sweden. The Norwegian part of the population has thus increased with 7% and the Swedish part of the population increased with 16% in comparison to the estimated population size in 2018.
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| 6. |
- López-Bao, José Vicente, et al.
(författare)
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Tracking neighbours promotes the coexistence of large carnivores
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The study of competition and coexistence among similar interacting species has long been considered a cornerstone in evolutionary and community ecology. However, understanding coexistence remains a challenge. Using two similar and sympatric competing large carnivores, Eurasian lynx and wolverines, we tested the hypotheses that tracking among heterospecifics and reactive responses to potential risk decreases the probability of an agonistic encounter when predators access shared food resources, thus facilitating coexistence. Lynx and wolverines actively avoided each other, with the degree of avoidance being greater for simultaneous than time-delayed predator locations. Wolverines reacted to the presence of lynx at relatively short distances (mean: 383 m). In general, lynx stayed longer, and were more stationary, around reindeer carcasses than wolverines. However, when both predators were present at the same time around a carcass, lynx shortened their visits, while wolverine behavior did not change. Our results support the idea that risk avoidance is a reactive, rather than a predictive, process. Since wolverines have adapted to coexist with lynx, exploiting lynx-killed reindeer carcasses while avoiding potential encounters, the combined presence of both predators may reduce wolverine kill rate and thus the total impact of these predators on semi-domestic reindeer in Scandinavia. Consequently, population management directed at lynx may affect wolverine populations and human-wolverine conflicts.
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| 7. |
- Löberg, Johanna, 1981, et al.
(författare)
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Electronic Properties of TiO2 Nanoparticles Films and the Effect on Apatite-Forming Ability.
- 2013
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Ingår i: International journal of dentistry. - : Hindawi Limited. - 1687-8728 .- 1687-8736. ; 2013
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Tidskriftsartikel (refereegranskat)abstract
- Nanoparticle-covered electrodes have altered properties as compared to conventional electrodes with same chemical composition. The changes originate from the large surface area and enhanced conduction. To test the mineralization capacity of such materials, TiO2 nanoparticles were deposited on titanium and gold substrates. The electrochemical properties were investigated using cyclic voltammetry and impedance spectroscopy while the mineralization was tested by immersion in simulated body fluid. Two types of nucleation and growth behaviours were observed. For smooth nanoparticle surfaces, the initial nucleation is fast with the formation of few small nuclei of hydroxyapatite. With time, an amorphous 2D film develops with a Ca/P ratio close to 1.5. For the rougher surfaces, the nucleation is delayed but once it starts, thick layers are formed. Also the electronic properties of the oxides were shown to be important. Both density of states (DOS) in the bandgap of TiO2 and the active area were determined. The maximum in DOS was found to correlate with the donor density (N d ) and the active surface area. The results clearly show that a rough surface with high conductivity is beneficial for formation of thick apatite layers, while the nanoparticle covered electrodes show early nucleation but limited apatite formation.
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| 8. |
- Mattisson, Jenny, et al.
(författare)
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Effects of Species Behavior on Global Positioning System Collar Fix Rates
- 2010
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Ingår i: Journal of Wildlife Management. - : Wiley. - 0022-541X .- 1937-2817. ; 74, s. 557-563
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Tidskriftsartikel (refereegranskat)abstract
- Use of Global Positioning System (GPS) telemetry is increasing in wildlife studies and has provided researchers and managers with new insight into animal behavior. However, performance of GPS collars varies and a major concern is the cause of unsuccessful fixes. We examined possible factors causing missed fixes in GPS collars on sympatric free-ranging Eurasian lynx (Lynx lynx) and wolverines (Gulo gulo) in northern Sweden. We tested for effects of species, activity, habitat, individual, and collar on fix rate. Species was the most important factor affecting fix rate. Fix rate of GPS collars on lynx (80%) was almost twice as high as on wolverines (46%). Fix rate decreased during periods of low activity (day beds) for both species. Fix rate also decreased for females (both lynx and wolverine) for a period after they gave birth. We found no effect of proportion of forest within individual home range on fix rate. We conclude that species behavior, characteristics, and activity pattern are important factors affecting fix rate that we recommend be taken into consideration prior to analyzing GPS location data.
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| 9. |
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| 10. |
- Mattisson, Jenny, et al.
(författare)
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Factors affecting Eurasian lynx kill rates on semi-domestic reindeer in northern Scandinavia: Can ecological research contribute to the development of a fair compensation system?
- 2011
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 144, s. 3009-3017
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Tidskriftsartikel (refereegranskat)abstract
- Semi-domestic reindeer (Rangifer tarandus) are the main prey for lynx (Lynx lynx) in northern Scandinavia. This causes large, but poorly documented, losses of reindeer. Although the compensation schemes differ between Norway and Sweden, there is a legal requirement in both Scandinavian countries that losses of semi-domestic reindeer to large carnivores should be fully compensated. The current level of compensation payment is based on limited data on lynx kill rates on reindeer. The main goal of this study was to quantify lynx kill rates on reindeer across a range of ecological conditions in northern Scandinavia. A total of 35 lynx were monitored during 3667 days. All lynx individuals killed reindeer. However, we observed a high variation in individual kill rates. Kill rates were strongly affected by sex and social status (i.e. females with and without kittens), as well as season and reindeer availability. The highest kill rates were observed in summer for male lynx, and the lowest were observed during winter for solitary lynx at low reindeer density. In summer, several female lynx switched completely to small prey species even at high densities of reindeer. The present political goals for lynx conservation in Scandinavia require that lynx occur in the reindeer husbandry area where reindeer are the only suitable ungulate prey available. Accordingly, it is therefore impossible to have the total prevention of depredation as a management goal. Rather depredation levels must be limited such that they are considered acceptable, and fair compensation payments should be paid. Our study is the first empirical quantification of the magnitude of lynx depredation on semi-domestic reindeer. This is an important step necessary to enable the setting of fair compensation levels and will hopefully lead to a reduction in conflict level concerning the potential impacts that lynx have on reindeer. (C) 2011 Elsevier Ltd. All rights reserved.
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