The most common framework under which ungulate migration is studied predicts that it is driven by spatio–temporal variation in plant phenology, yet other hypotheses may explain differences within and ...between species. To disentangle more complex patterns than those based on single species/ single populations, we quantified migration variability using two sympatric ungulate species differing in their foraging strategy, mating system and physiological constraints due to body size. We related observed variation to a set of hypotheses. We used GPS‐collar data from 537 individuals in 10 roe Capreolus capreolus and 12 red deer Cervus elaphus populations spanning environmental gradients across Europe to assess variation in migration propensity, distance and timing. Using time‐to‐event models, we explored how the probability of migration varied in relation to sex, landscape (e.g. topography, forest cover) and temporally‐varying environmental factors (e.g. plant green‐up, snow cover). Migration propensity varied across study areas. Red deer were, on average, three times more migratory than roe deer (56% versus 18%). This relationship was mainly driven by red deer males which were twice as migratory as females (82% versus 38%). The probability of roe deer migration was similar between sexes. Roe deer (both sexes) migrated earliest in spring. While territorial male roe deer migrated last in autumn, male and female red deer migrated around the same time in autumn, likely due to their polygynous mating system. Plant productivity determined the onset of spring migration in both species, but if plant productivity on winter ranges was sufficiently high, roe deer were less likely to leave. In autumn, migration coincided with reduced plant productivity for both species. This relationship was stronger for red deer. Our results confirm that ungulate migration is influenced by plant phenology, but in a novel way, that these effects appear to be modulated by species‐specific traits, especially mating strategies.
Dietary choices are central to our understanding of ecology and evolution. Still, many aspects of food choice have been hampered by time consuming procedures and methodological problems. Faster and ...cheaper methods, such as DNA metabarcoding, have therefore been widely adopted. However, there is still very little empirical support that this new method is better and more accurate compared to the classic methods. Here, we compare DNA metabarcoding to macroscopic identifications of rumen contents in two species of wild free-ranging ungulates: roe deer and fallow deer. We found that the methods were comparable, but they did not completely overlap. Sometimes the DNA method failed to identify food items that were found macroscopically, and the opposite was also true. However, the total number of taxa identified increased using DNA compared to the macroscopic analysis. Moreover, the taxonomic precision of metabarcoding was substantially higher, with on average 90% of DNA-sequences being identified to genus or species level compared to 75% of plant fragments using macroscopy. In niche overlap analyses, presence/absence data showed that both methods came to very similar conclusions. When using the sequence count data and macroscopic weight, niche overlap was lower than when using presence-absence data yet tended to increase when using DNA compared to macroscopy. Nevertheless, the significant positive correlation between macroscopic quantity and number of DNA sequences counted from the same plant group give support for the use of metabarcoding to quantify plants in the rumen. This study thus shows that there is much to be gained by using metabarcoding to quantitatively assess diet composition compared to macroscopic analysis, including higher taxonomic precision, sensitivity and cost efficiency.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Wildlife hosts may serve as reservoirs for strongyles, which can be transmitted to domestic livestock. Therefore, studies evaluating nemabiome compositions in wildlife ruminants are of great use in ...assessing the possibility of transmission of important nematode pathogens to domestic sheep in Sweden. First, fecal samples were collected from roe deer (n = 125), fallow deer (n = 106), red deer (n = 18) and mouflon (n = 13) in south central Sweden during the hunting season in 2019. Second, after fecal examination samples were cultured and the larvae were harvested, followed by DNA extractions. Third, all samples were barcoded and processed for sequence analysis on the PacBio platform. Finally, bioinformatic sequence analysis was conducted with DADA2, while species diversity and richness, as well as interactions between the different hosts, were calculated and analyzed in R. Nematode ITS2 sequences were found in 225 of 262 (86%) samples. In total, 31 taxa were identified, among which 26 (86%) to the species level. These were found in different combinations, among which 24 (77%) occurred in roe deer, 19 (61%) in fallow deer, 20 (65%) in red deer and 10 (32%) in mouflon. Five of the species found are known to be associated with livestock (Chabertia ovina, Haemonchus contortus, Oesophagostomum venulosum, Teladorsagia circumcincta and Trichostrongylus axei). However, in the present study the relative abundance and prevalence of most of these species were low. The most striking exception was T. axei, which was relatively abundant in all wildlife hosts. Mostly a wide range of wildlife specific nematodes such as Ostertagia leptospicularis and Spiculopteragia spp. were identified including the invasive nematode Spiculopteragia houdemeri, which was found for the first time in red deer, fallow deer, and mouflon in Sweden. The difference in the number of shared species between mouflon and all cervids (n = 6) was less than among all three cervids (n = 8). In this study, we investigated the community structure of parasitic intestinal nematodes in four wildlife hosts, and we found that the majority of the parasite species identified were wildlife specific. We also found a new, potentially invasive species not reported before. After comparing the nemabiome of the wildlife hosts in this study with a previous study in sheep from the same geographical region, we conclude that the horizontal transmission potential appears to be relatively low. Still, cross-infections of nematodes between game and sheep cannot be completely ignored.
Landscapes composed of agricultural land mixed with forest are desirable since they provide a wide range of diversified ecosystem services, unlike specialized agricultural landscapes, but that ...creates a trade-off between these land uses since wildlife usually feed on crops and reduce yields. In Nordic countries, where human population density is low and game hunting can be a viable economic alternative, mixed landscape systems are particularly interesting. To evaluate the economic sustainability of such systems we need to quantify wildlife damage to crops. One important species, being popular among Swedish hunters and therefore economically valuable, is fallow deer (Dama dama). Our objective was to evaluate the economic sustainability of mixed landscape systems including cultivated fields and commercial hunting of fallow deer. We studied the effects of excluding fallow deer by using 86 exclosures and adjacent plots in winter wheat and oat fields in south-west Sweden. We analyzed yield losses and interactions between spatial and temporal grazing patterns, anthropogenic landscape features, and topological characteristics of the landscape. We found that animals avoided exposed spots, irrespective of distance from human activity. We also found a seasonal grazing pattern related to the different growing periods of winter wheat (more grazed, emerging in autumn) and spring oat (less grazed, emerging in spring). We then compared the costs of crop damage against the commercial value of fallow deer hunting. The damage amounted to 375 ±196 € ha-1 for wheat and 152 ±138 € ha-1 for oat, corresponding to a total cost per animal of 82.7 ±81.0 €, while each animal had an estimated market value of approximately 100 €. Therefore the value of fallow deer presence compensated for the associated cost of crop damage. Profit could be further improved in this case by adopting additional management strategies. In general our study confirmed the economic feasibility of this particular mixed land management.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
On an evolutionary time scale, competition for food drives species formation by genetic adaptations to the environment and subsequent niche separation. On a short-term scale, animals use different ...strategies to meet their nutritional requirements, which ultimately influence their fitness. Understanding these adaptations in herbivores is especially important in temperate climates where animals have adapted both physiologically and behaviorally to seasonal variations in order to meet their nutritional requirements. The aim of this project was to investigate temporal variation in chemical composition of rumen content between two coexisting species of large herbivores, the native roe deer (
Capreolus capreolus L
.) and the introduced fallow deer (
Dama dama L
.), as well as a potential effect of competition on niche separation (interspecific differences in rumen nutrient composition). We analyzed 345 rumen samples collected from animals at one 95 km
2
estate, Koberg, in southwestern Sweden. Based on samples from all seasons, temporal variation in nutrient composition and interspecific differences between the two deer species were investigated under two contrasting fallow deer population densities. Results revealed that nutrient composition varied between species and across seasons. Roe deer had a higher proportion of rumen protein compared to fallow deer, with the highest proportions in spring. In contrast, fallow deer had a higher proportion of rumen hemicellulose compared to roe deer in spring, while no differences in nutrient composition between species could be found in fall. Overall, there were greater differences between the two species when fallow deer density was high and competition likely more pronounced than when fallow deer density was low. The results from this study can be used to understand interspecific competition and how it fosters niche separation between coexisting large herbivores.
1. Because many large mammal species have wide geographical ranges, spatially distant populations may be confronted with different sets of environmental conditions. Investigating how home range (HR) ...size varies across environmental gradients should yield a better understanding of the factors affecting large mammal ecology. 2. We evaluated how HR size of a large herbivore, the roe deer (Capreolus capreolus), varies in relation to seasonality, latitude (climate), weather, plant productivity and landscape features across its geographical range in Western Europe. As roe deer are income breeders, expected to adjust HR size continuously to temporal variation in food resources and energetic requirements, our baseline prediction was for HR size to decrease with proxies of resource availability. 3. We used GPS locations of roe deer collected from seven study sites (EURODEER collaborative project) to estimate fixed-kernel HR size at weekly and monthly temporal scales. We performed an unusually comprehensive analysis of variation in HR size among and within populations over time across the geographical range of a single species using generalized additive mixed models and linear mixed models, respectively. 4. Among populations, HR size decreased with increasing values for proxies of forage abundance, but increased with increases in seasonality, stochastic variation of temperature, latitude and snow cover. Within populations, roe deer HR size varied over time in relation to seasonality and proxies of forage abundance in a consistent way across the seven populations. Thus, our findings were broadly consistent across the distributional range of this species, demonstrating a strong and ubiquitous link between the amplitude and timing of environmental seasonality and HR size at the continental scale. 5. Overall, the variability in average HR size of roe deer across Europe reflects the interaction among local weather, climate and seasonality, providing valuable insight into the limiting factors affecting this large herbivore under contrasting conditions. The complexity of the relationships suggests that predicting ranging behaviour of large herbivores in relation to current and future climate change will require detailed knowledge not only about predicted increases in temperature, but also how this interacts with factors such as day length and climate predictability.
Cloth-dragging is the most widely-used method for collecting and counting ticks, but there are few studies of its reliability. By using cloth-dragging, we applied a replicated line transects survey ...method, in two areas in Sweden with different
Ixodes ricinus
tick-densities (low at Grimsö and high at Bogesund) to evaluate developmental stage specific repeatability, agreement and precision in estimates of tick abundance. ‘Repeatability’ was expressed as the Intraclass Correlation Coefficient (ICC), ‘agreement’ with the Total Deviation Index (TDI) and ‘precision’ by the coefficient of variation (CV) for a given dragging distance. Repeatability (ICC) and agreement (TDI) were higher for the most abundant instar (nymphs) and in the area of higher abundance. At Bogesund tick counts were higher than at Grimsö and so also repeatability, with
fair
to
substantial
ICC estimates between 0.22 and 0.75, and TDI ranged between 1 and 44.5 counts of difference (thus
high
to
moderate
agreement). At Grimsö, ICC was
poor
to
moderate
and ranged between 0 and 0.59, whereas TDI remained low with estimates lower or equal to 1 count (thus
high
agreement). Despite a 100-fold lower abundance at Grimsö, the same level of precision for nymphs could be achieved with a 70% increase of dragging effort. We conclude that the cloth-dragging technique is useful for surveying ticks’ and primarily to estimate abundance of the nymphal stage, whereas it rarely will be recommended for larvae and adults.
Recent studies have examined the ecological and evolutionary bases for variation in animal personality. However, only a few such studies have examined how foraging parameters are influenced by ...different personality domains. In wild ungulates, the trade-off between the time spent on food intake and antipredator behaviour differs between individuals, but the underlying reason for this is not yet well understood. One possibility is that this trade-off reflects personality dimensions such as boldness. To relate foraging decisions to personality we measured personality and performed feeding experiments with familiar and novel food in familiar and novel situations. We measured personality traits in 15 tame fallow deer, using novel object tests (NO), behavioural observations (BO) and personality ratings (PR). Boldness dimensions were found using PR and NO, dominance dimensions were found using BO and PR, and a flexibility dimension was found using BO. Multitrait–multimethod analysis showed that similar dimensions were significantly correlated across different methods and that different dimensions were not significantly correlated, even if measured using the same method. We also found that novel food eaten in familiar situations and familiar food eaten in novel situations were strongly related to boldness but not dominance, flexibility or age. Thus the trade-off between the benefits of gaining more food and the costs of reduced vigilance or increased toxin ingestion reflect boldness. These findings highlight the nature of personality dimensions in ungulates and how boldness impacts foraging behaviour.
Incidence of tick-borne encephalitis (TBE) has increased during the last years in Scandinavia, but the underlying mechanism is not understood. TBE human case data reported between 2010 and 2021 were ...aggregated into postal codes within Örebro County, south-central Sweden, along with tick abundance and environmental data to analyse spatial patterns and identify drivers of TBE. We identified a substantial and continuing increase of TBE incidence in Örebro County during the study period. Spatial cluster analyses showed significant hotspots (higher number of cases than expected) in the southern and northern parts of Örebro County, whereas a cold spot (lower number of cases than expected) was found in the central part comprising Örebro municipality. Generalised linear models showed that the risk of acquiring TBE increased by 12.5% and 72.3% for every percent increase in relative humidity and proportion of wetland forest, respectively, whereas the risk decreased by 52.8% for every degree Celsius increase in annual temperature range. However, models had relatively low goodness of fit (R
< 0.27). Results suggest that TBE in Örebro County is spatially clustered, however variables used in this study, i.e., climatic variables, forest cover, water, tick abundance, sheep as indicator species, alone do not explain this pattern.
In Europe, Ixodes ricinus (Acari: Ixodidae) is the most widespread and abundant tick species, acting as a vector for several microorganisms of medical and veterinary importance. In Northern and ...Central Europe, the tick has a bimodal activity pattern consisting of a peak in spring to the beginning of summer and a second peak at the end of summer. However, several findings of ticks on animals during winter have been reported, which raises the question of whether this is an overwintering strategy or whether ticks are active during winter in Scandinavia. The objectives of our study were to determine (i) whether ticks were active and finding hosts during winter, (ii) whether they parasitize their hosts, and (iii) what climatic factors-i.e., temperature, snow depth and precipitation-govern tick winter activity.
Throughout three winter seasons, we examined wild-living and free-ranging roe deer (Capreolus capreolus) for ticks on 332 occasions. In total, 140 individual roe deer were captured in two climatically contrasting sites in south-central Sweden, Grimsö and the Bogesund research area, respectively. We re-examined individual roe deer up to 10 times within the same winter or approximately once a week (mean 10 days, median 7 days between re-examinations) and recorded the absence or presence of ticks on the animals, and tested to what extent meteorological factors affected tick activity. To determine the attachment day, we used the coxal/scutal index of 18 nymphs and 47 female ticks.
In total, 243 I. ricinus were collected from 301 roe deer captures between 14 December and 28 February at the Bogesund study site during three subsequent years (2013/2014-2015/2016). We found attached ticks every third to every second examination (32%, 48% and 32% of the examinations, respectively). However, we collected only three I. ricinus females from 31 roe deer captures at the Grimsö study site between 17 December 2015 and 26 February 2016. At the Bogesund study site, based on 192 captures of previously examined deer, we collected 121 ticks, and ticks were found at 33%, 48% and 26% of the examinations during the respective winters. The probability of finding an attached tick on a roe deer at a temperature of -5 °C was > 8% ± 5 (SE), and that probability increased to almost 20% ± 7 (SE) if the air temperature increased to 5 °C.
To the best of our knowledge, this is the first time that winter-active nymphs and female ticks have been documented to attach and feed on roe deer during winter (December to February) in Scandinavia. The main weather conditions regulating winter activity for females were temperature and precipitation, and the lowest estimated air temperature for finding an active tick was well below 5 °C. The behaviour of winter-active and blood-feeding ticks was documented over several winters and in two contrasting areas, implying that it is a common phenomenon that should be investigated more thoroughly, since it may have important consequences for the epidemiology of tick-borne pathogens.
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