Browsing by Subject "reindeer"

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  • Jokelainen, Pikka; Moroni, Barbara; Hoberg, Eric; Oksanen, Antti; Laaksonen, Sauli (2019)
    Reindeer (Rangifer tarandus tarandus) host numerous parasites. Although there is a general knowledge about parasite diversity in reindeer, detailed baseline information about parasitic infections is limited. Detailed knowledge of parasite prevalence and diversity provide a pathway for more targeted parasite control, an increasing need expected in the future. The main aim of our cross-sectional study was to estimate the prevalence of gastrointestinal parasites in semidomesticated reindeer calves. The 480 reindeer calves included in our study were aged 6–7 months, originated from 9 reindeer herding cooperatives in Finland and 1 in Norway, and were slaughtered during September–November 2015 in 10 reindeer slaughterhouses. All the reindeer calves passed meat inspection, and the detected parasitic infections were subclinical. As the reindeer included in this study were young animals intended for slaughter, they had never been administrated any antiparasitic treatment. Assessments of gastrointestinal parasitism among these reindeer calves were based on fecal examination and morphological identification of coccidian oocysts or helminth eggs. Individual fecal samples collected from the rectum of each of the reindeer were examined using a modified McMaster method. Most (78.3%) of the reindeer calves had eggs or oocysts of at least one parasite species in their feces, and more than half (53.5%) had a mixed infection. Strongylid eggs were detected in 75.6%, Eimeria sp. oocysts in 50.6%, Moniezia sp. eggs in 28.1%, Nematodirus sp. eggs in 22.1%, Capillaria sp. eggs in 9.4%, and Trichuris sp. eggs in 0.6% of the samples. The prevalence of gastrointestinal parasites was similar or higher relative to previous estimates from the region; the proportion of reindeer calves shedding strongylid eggs and the proportion of reindeer calves shedding Moniezia sp. eggs had increased. Prevalence varied by geographical region, which may reflect different herding practices or environmental parameters. Higher reindeer density was a risk factor for testing positive for Eimeria sp. oocysts, and the odds of testing positive for Nematodirus sp. eggs were higher if a peroral route was used for antiparasitic treatment in the reindeer herding cooperative. The mean proportion of reindeer estimated to receive antiparasitic treatment in Finland was 86% in 2004–2005 and 91% in 2014–2015. During the historical time frames of current management practices, this routine annual antiparasitic treatment of breeding reindeer has not decreased the prevalence of gastrointestinal parasites in reindeer calves, which can be seen as sentinels or indicators of the infection pressure.
  • Jokelainen, Pikka; Moroni, Barbara; Hoberg, Eric; Oksanen, Antti; Laaksonen, Sauli (2019)
    Reindeer (Rangifer tarandus tarandus) are known to host a wide variety of parasites, including those in the gastrointestinal system. Here, we review the current knowledge of the main gastrointestinal parasites of reindeer focusing on northern Fennoscandia, which comprises parts of Finland, Sweden, Norway and Russia. We explore both the historical baseline data for diversity and distribution and recent advancements in our understanding of parasite faunas in reindeer across this region. It is evident that the balance between reindeer and their gastrointestinal parasites, along with the potential for emergent disease in the changing world warrants careful monitoring and further studies.
  • Winquist, Emelie (Helsingin yliopisto, 2021)
    The heath vegetation in the Jauristunturit study area is highly affected by the reindeer fence that was built in the mid-1950s between Finland and Norway, to prevent summer grazing in the Norwegian side. In the study area, the Finnish and Norwegian pastures are used during different seasons, causing differences in reindeer grazing history, and with time differences in vegetation. Additionally, local topography also impacts the vegetation composition and structure creating variation in local vegetation patterns. My research questions are: How vegetation patterns differ between summer- and winter- grazed areas, and which plant functional groups have the most significant difference? How local topography affects vegetation patterns, and does the effect of topography differ between summer and winter pastures? The data was collected from five 400 m long transects that crossed the fence and had vegetation plots with 10-m intervals. The %-cover and height of each vascular plant, bryophyte, and lichen species were estimated from 0.25 m2 plots. Later, species data was grouped into functional groups and general linear models were used to analyze differences in cover, height, species number, biomass, and leaf-area indices between countries. Topography indices were calculated in GIS for each plot and analyzed with random forest models to find out the most important topography indices explaining vegetation patterns. The vegetation data was collected by four teams, and therefore, the comparability in the collected data between teams was analyzed. Significant vegetation differences were found in the ground layer, with higher cover and biomass of bryophytes on the Finnish side (mean biomass 168.2 vs. 65.2 g m-2). Reindeer lichens were more abundant on the Norwegian side (mean biomass 197.0 vs. 2.9 g m-2) which is visible in aerial and satellite images and in the field. Among vascular plants, evergreen dwarf shrubs had higher biomass and leaf area index on the Finnish side and dwarf birch had higher cover and height on the Norwegian side. Topography indices had a higher level of variance explained on the Norwegian side, and higher at the ground layer compared to vascular plants. Elevation had the greatest impact on vegetation, and after that, topography protection index for 50 m and depth to water stream network for 2 and 10 ha. The differences between data collectors were not considered to have a major impact on the results. The results indicate that there are significant differences in vegetation between summer- and winter-grazed areas, mainly in the ground layer, and most differences are caused by differences in reindeer grazing history, but also local topography has an impact.
  • Fagerholm, Freja (Helsingin yliopisto, 2021)
    In the process of decomposition soil carbon is transformed into CO2 by microbial respiration, which makes decomposition a key process for understanding carbon cycling an releases of CO2. Since the northern permafrost regions contain half of all belowground carbon and the tundra regions are expected to be markedly affected by climate warming, it is of particular interest to understand how warming will affect decomposition in the tundra. Decomposition is however influenced by many factors, from climatic factors such as temperature and precipitation to the belowground organisms inhabiting the soils and the aboveground system dictating the litter that falls to the ground and is decomposed. Further, grazing has been shown to oppose some of the effects of warming on tundra. In this thesis I analyzed data collected from two long-term field experiments, one in Kilpisjärvi (NW Finland) and the other close to Kangerlussuaq Fjord (SW Greenland), both using fencing for manipulation of grazing regime and open-top chambers for artificial warming. My aim was to not only investigate how warming and grazing affect decomposition, but also to understand whether the magnitude of changes in decomposition can be explained by changes in plant community traits and soil characteristics. I found that in contrast to my hypothesis, warming decreased decomposition in Kangerlussuaq, where the soil was drier and contained less carbon than in Kilpisjärvi. I found no effects of grazing on decomposition, plant community traits nor soil characteristics in neither of the study locations. Neither did I find any consistent associations between changes in decomposition and changes in plant community traits, indicating that the effect of litter quality on decomposition is minor in these areas likely rather limited by climate. I found an association for increased decomposition when plant community C:N ratio and C:P ratio increased as a response to warming, but only in Kilpisjärvi, and since increased plant community C:N and C:P ratios are linked to resistant litter this positive effect is unlikely driven by enhanced litter quality. However, I did find a positive relationship between increased root biomass and increased decomposition as a response to warming that was consistent across areas and grazing regimes, indicating that warming can boost decomposition in different tundra habitats by promoting root growth.
  • Puikkonen, Laura (Helsingin yliopisto, 2020)
    Individuals of long-lived animal species can improve their reproductive success through experience. While individual’s resources available for survival and reproduction decrease toward the end of its lifespan through senescence, terminal investment hypothesis predicts the less likely old individuals reproduce again the more they invest in their current offspring. Experience gained through a long lifespan might have an important role in changing behavior to optimize the use of resources and compensate the effects of senescence. In addition, behavioral plasticity allows animals to respond changes in their habitat within much shorter timespan than on an evolutionary timescale. Svalbard reindeer (Rangifer tarandus platyrhynchus) is a wild subspecies of reindeer. It is only found in Svalbard, a remote archipelago in the Arctic with extreme weather conditions rapidly changing due to climate change. It has been isolated at least 5000 years and adapted to a barren habitat with nearly no hunting, predation or harassment of flying insects. The objective of this study is to investigate the effect of age and a calf at heel in Svalbard reindeer females’ maternal, vigilant, and social behavior and time budget in the light of life history theory and its senescence and terminal investment hypotheses. I carried out the field work for the study in two periods in summer in Semmeldalen valley and the south-western part of Reindalen valley on the island of Spitsbergen, Svalbard. I collected behavioral data on marked individuals by instant scan sampling and focal watch methods, wrote observations down manually and later fed them into computer. In addition, I have used birth year data collected by the long-term monitoring program by the Norwegian Polar Institute. I used generalized linear mixed models to analyze the effects of age and calf at heel to the behavior of females. The main results include that young dams maintained shorter distance to their calf in July than in August, and old females were less vigilant. Younger dams and older females without calves were in smaller groups than older dams and younger females without calves. In addition, females with calves spend proportionately less time lying down than females without calves. Dams maintained a longer distance to the nearest neighbor than females without calves. Older dams spend proportionately more time feeding and in groups in August than younger dams. These results show that the age and calf at heel do play a role in the behavior of Svalbard reindeer females and the effect varies over the course of the short Arctic summer. Experience may make older females more effective mothers by optimize the use of resources for example from vigilance to feeding in a predator-free environment. On the other hand, senescence may affect the amount of energy females can spend on their calves, potentially influencing their survival.
  • Jessen, Maria-Theresa; Kaarlejärvi, Elina; Olofsson, Johan; Eskelinen, Anu (2020)
    Variation in intraspecific traits is one important mechanism that can allow plant species to respond to global changes. Understanding plant trait responses to environmental changes such as grazing patterns, nutrient enrichment and climate warming is, thus, essential for predicting the composition of future plant communities. We measured traits of eight common tundra species in a fully factorial field experiment with mammalian herbivore exclusion, fertilization, and passive warming, and assessed how trait responsiveness to the treatments was associated with abundance changes in those treatments. Herbivory exhibited the strongest impact on traits. Exclusion of herbivores increased vegetative plant height by 50% and specific leaf area (SLA) by 19%, and decreased foliar C:N by 11%; fertilization and warming also increased height and SLA but to a smaller extent. Herbivory also modulated intraspecific height, SLA and foliar C:N responses to fertilization and warming, and these interactions were species-specific. Furthermore, herbivory affected how trait change translated into relative abundance change: increased height under warming and fertilization was more positively related to abundance change inside fences than in grazed plots. Our findings highlight the key role of mammalian herbivory when assessing intraspecific trait change in tundra and its consequences for plant performance under global changes.
  • Pekkarinen, Antti-Juhani; Kumpula, Jouko; Tahvonen, Olli (2017)
    Ungulate grazing and trampling strongly affect pastures and ecosystems throughout the world. Ecological population models are used for studying these systems and determining the guidelines for sustainable and economically viable management. However, the effect of trampling and other resource wastage is either not taken into account or quantified with data in earlier models. Also, the ability of models to describe the herbivore impact on pastures is usually not validated. We used a detailed model and data to study the level of winter- and summertime lichen wastage by reindeer and the effects of wastage on population sizes and management. We also validated the model with respect to its ability of predicting changes in lichen biomass and compared the actual management in herding districts with model results. The modeling efficiency value (0.75) and visual comparison between the model predictions and data showed that the model was able to describe the changes in lichen pastures caused by reindeer grazing and trampling. At the current lichen biomass levels in the northernmost Finland, the lichen wastage varied from 0 to 1 times the lichen intake during winter and from 6 to 10 times the intake during summer. With a higher value for wastage, reindeer numbers and net revenues were lower in the economically optimal solutions. Higher wastage also favored the use of supplementary feeding in the optimal steady state. Actual reindeer numbers in the districts were higher than in the optimal steady-state solutions for the model in 18 herding districts out of 20. Synthesis and applications. We show that a complex model can be used for analyzing ungulate-pasture dynamics and sustainable management if the model is parameterized and validated for the system. Wastage levels caused by trampling and other causes should be quantified with data as they strongly affect the results and management recommendations. Summertime lichen wastage caused by reindeer is higher than expected, which suggests that seasonal pasture rotation should be used to prevent the heavy trampling of winter lichen pastures during summer. In the present situation, reindeer numbers in northernmost Finland are in most cases higher than in the management solutions given by the model.
  • Toivonen, Nina (Helsingfors universitet, 2007)
    Poronvasojen syysteurastukset ovat porotalouden tuottavuuden perusta. Kesän aikana hyvin kasvaneet vasat ovat syysteurastuksissa painavia ja hyväkuntoisista eläimistä voidaan valita parhaimpia jalostukseen. Kasvun ja kehityksen sekä immuunipuolustuksen muokkautumisen kannalta vasojen alkuelämän terveydelliset haasteet ovat merkittävässä asemassa. Tutkielma koostuu kirjallisuuskatsauksesta ja tutkimusosasta. Kirjallisuuskatsauksessa lähestytään vasojen selviytymistä ensimmäisistä elinviikoistaan sekä vaadinten että vasojen näkökulmasta. Vaatimien kunnon ja ympäristöolosuhteiden välistä yhteyttä selvitetään esimerkein sekä paneudutaan vasan mahdollisuuksiin suojautua infektioilta ja taudinaiheuttajilta ensimmäisten elinviikkojensa aikana. Ternimaidon ja erityisesti sen sisältämien immunoglobuliinien merkitystä infektioissa arvioidaan. Tunnettuina infektionaiheuttajina tutkielman molemmissa osioissa on käytetty kahta poron suolistoloisista, giardiaa ja kryptosporidia. Tutkimusosassa selostetaan Paliskuntain yhdistyksen koetokalla vuonna 2004 tehty tutkimus. Siinä pyrittiin selvittämään aikaisessa vaiheessa vasoilla ilmenevien tulehdusten ja loistartuntojen vaikutusta vasojen vastustuskyvyn ja painon kehittymiseen sekä selviytymiseen myöhemmin. Tutkittiin myös maternaalisen immuniteetin vaikutusta loistartuntoihin sekä akuutin vaiheen proteiinien käyttöä poronvasojen subkliinisten infektioiden mittareina sekä ympäristöstä tulevan infektiopaineen arvioinnissa. Aikaisempien kokeiden perusteella odotettiin, että voimakas varhainen loistartunta heti ensimmäisinä elinviikkoina voisi aiheuttaa vasoilla tulehdusvasteen, jolla saattaisi olla merkitystä myöhemmän vastustuskyvyn kehittymisen kannalta. Tutkimuksissa vasoilta (n = 54) otettiin veri- ja ulostenäytteitä sekä ne punnittiin kahdesti päiväkasvujen laskemiseksi. Vaatimilta (n = 54) otettiin kerran veri- ja ulostenäyte. Verinäytteistä määritettiin akuutin vaiheen proteiineista seerumin amyloidi-A (SAA), haptoglobiini (Hp) sekä fibrinogeeni. Lisäksi määritettiin valkosolujen kokonaismäärä. Ulostenäytteistä tutkittiin giardiat ja kryptosporidit. Kaikilta vasoilta löytyi ulostenäytteestä giardioita. Voidaankin sanoa, että se on laajalti levinnyt poronvasojen keskuudessa. Kryptosporideja löydettiin vain 12 vasalta 54:stä ja aiheutunut infektio todettiin lieväksi lähes kaikilla. Loisten aiheuttama tulehdusreaktio vasoilla oli lyhytaikainen eikä sillä näyttänyt olevan vaikutusta vasojen terveyteen ja kasvuun hyvissä olosuhteissa. Tutkituista veriarvoista sekä SAA että Hp nousivat kahteen elinviikkoon saakka ja jäivät tälle tasolle pitkäksi aikaa. Tulos oli yllättävä ja saattaa osaltaan johtua ternimaidon sisältämistä aineista sekä edeltävistä kokeista poikkeavalla infektiopaineella. Vasat kasvoivat tässä kokeessa hyvin. Infektioiden yleisinä mittareina akuutin vaiheen proteiinit lienevät parhaita. Subkliinisissä infektioissa niiden käyttökelpoisuus on epävarmaa. Lievän ympäristöperäisen infektiopaineen mittaamiseen akuutin vaiheen proteiinit sopivat kohtalaisesti, voimakkaan taas todennäköisesti hyvin. Vuodet ovat luonnonoloiltaan hyvin erilaisia keskenään. Tästä syystä eri olosuhteiden vaikutusten arviointi vasojen terveyteen ja eri tutkimuksia vertailu keskenään on vaikeaa.
  • Kylmämaa, Laura (Helsingin yliopisto, 2015)
    The aim of this study was to investigate how the quality of silage affects the silage intake of reindeer. There were two growth stages of primary growth and regrowth silage in the study. Aerobic stability of silage was observed after opening the silage bales. The experimental silages were made at the fields of MTT Agrifood Research Finland in Apukka, Rovaniemi. The study was conducted at the reindeer pen of Lapland Vocational College. There were four groups of female reindeer, six animals in each, and one silage type per group. Feeding trial lasted eight weeks with two weeks pre-period before. Reindeer were fed ad libitum in the mornings. The biggest differences of chemical composition of silages were between primary growth and regrowth silage. The growth stage did not affect to the chemical composition. Aerobic deterioration of silages was not observed during three weeks exposure to air because ambient temperature remained above zero almost constantly. Silage residue had lower D-value, crude protein, AAT and PBV content and higher concentration of NDF-fiber compared to the given feed. The selection of feed differed between primary growth and regrowth silage based on crude protein and water-soluble carbohydrate (WSC) contents. This is may be because of the excess of crude protein and WSC relative to nutrient requirements of reindeer or that the variables are correlated with the other variables which explain the intake. Silage intake was higher when dry-matter content was higher and lower when crude protein content was higher. WSC had slightly positive effect to the intake. Intake seemed to be curvilinearly related to the content of fermentation products. Effective utilization of silage requires analyses on the chemical composition of silage.
  • Happonen, Konsta; Muurinen, Lauralotta; Virtanen, Risto; Kaakinen, Eero; Grytnes, John-Arvid; Kaarlejarvi, Elina; Parisot, Philippe; Wolff, Matias; Maliniemi, Tuija (2021)
    Aim Land use is the foremost cause of global biodiversity decline, but species do not respond equally to land-use practices. Instead, it is suggested that responses vary with species traits, but long-term data on the trait-mediated effects of land use on communities are scarce. Here we study how forest understorey communities have been affected by two land-use practices during 4-5 decades, and whether changes in plant diversity are related to changes in functional composition. Location Finland. Time period 1968-2019. Major taxa studied Vascular plants. Methods We resurveyed 245 vegetation plots in boreal herb-rich forest understories, and used hierarchical Bayesian linear models to relate changes in diversity, species composition, average plant size, and leaf economic traits to reindeer abundance, forest management intensity, and changes in climate, canopy cover and composition. We also studied the relationship between species evenness and plant size across both space and time. Results Intensively managed forests decreased in species richness and had increased turnover, but management did not affect functional composition. Increased reindeer densities corresponded with increased leaf dry matter content, evenness and diversity, and decreased height and specific leaf area. Successional development in the canopy was associated with increased specific leaf area and decreased leaf dry matter content and height in the understorey over the study period. Effects of reindeer abundance and canopy density on diversity were partially mediated by vegetation height, which had a negative relationship with evenness across both space and time. Observed changes in climate had no discernible effect on any variable. Main conclusions Functional traits are useful in connecting vegetation changes to the mechanisms that drive them, and provide unique information compared to turnover and diversity metrics. These trait-dependent selection effects could inform which species benefit and which suffer from land-use changes and explain observed biodiversity changes under global change.