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 Grimso 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 Grimso 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 Grimso, 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 Grimso, 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.

Background: Browsing repellents are widely used to deter large herbivores from consuming plants of ecological,economic and aesthetic importance. Understanding how these repellents function on a behavioural mechanisticlevel is critical to predicting effectiveness. Here, we illustrate how these mechanisms can be tested, by exposing amodel mammalian herbivore, the fallow deer, to different concentrations of a commercial chemical repellent(HaTe2) in two-choice feeding trials.

Results:The repellent acted as a defensive chemical for the food by both reducing visitation and the amountconsumed. Deer favoured the less defended feeders before ingesting any food, suggesting that the repellentaltered olfactory and/or visual cues. Deer also consumed less of the more defended food when choosing betweenlow and high repellent feeders than no and low repellent feeders, indicating that the repellent modified flavourand/or sensation. Repellent effectiveness declined with increased exposure, suggesting that consumption had nonegative post-ingestive effects, and thus, deterrence was not caused by a conditioned aversion or irritation. Instead,this pattern suggests that deer learned, through repeated sampling of repellent-treated food, that there was noadverse physiological effect of ingesting it.

Conclusions:These results imply that HaTe2 repellent will not be effective over prolonged periods or in theabsence of alternative untreated food. Understanding the mechanisms driving repellent function using two-choicetrials could help practitioners decide whether a particular repellent is likely to be effective against mammalianherbivory in their management scenario.

Browsing can reduce forest productivity, particularly when the apical shoots of trees are damaged. Repellents are used widely to reduce browsing, but application is costly. To improve efficiency, it may be possible to take advantage of associational plant refuge effects, requiring repellents to be applied only to some trees or parts of trees, or reapplied less frequently. Using captive moose (Alces alces) and constructed stands of Scots pine (Pinus sylvestris), we tested for potential refuges by applying a commercial repellent (HaTe2) to all, alternate or none of the apical shoots, or all of the previous-year apical shoots. We also tested for potential refuges under field conditions, applying the repellent to all, alternate or none of the apical pine shoots in forest stands. Captive moose (two individuals in a 2.1-ha enclosure, similar to 95 individuals km(-2)) browsed 100% of trees, but were significantly less likely to browse apical shoots treated with repellent. Associational refuge was ineffective both within and between trees. In the field (0.84 moose km(-2)), only 1.3% of trees sustained browsing damage. Applying the repellent to the apical shoots of pines had no direct repellent effect nor any within-plant associational effects. Trees with treated apical shoots provided some protection for untreated neighbouring trees, but this was not biologically meaningful given the low percentage of trees browsed overall. Here, a simple captive experiment was not predictive of the browsing response observed in the field, demonstrating the need to test repellent application strategies in situ.

For social foragers, movement as a group could increase foraging efficiency through collective discovery of high-quality food sources. This would require an efficient mechanism for transferring information about food quality between individuals. Conversely, the constraints of foraging as a cohesive group could decrease efficiency; grouping may persist to serve other functions such as protection from predators. To test what drives cohesion in herbivores, we manipulated patch shape and within-patch pattern of food quality and quantified the effects on group level diet selection by a social herbivore, the fallow deer, Dama dama. We arranged feeders containing fodder in lines or blocks, and manipulated the pattern of food quality within patches by adding tannin, a plant secondary compound that decreases palatability. We quantified the relative consumption of low- and high-tannin food to compare diet selectivity at the group level between patch treatments. If group foraging evolved to increase foraging efficiency, altering the spatial arrangement of food should not affect diet selectivity because information about food location and quality is shared. We found, however, that the herd expressed different levels of selectivity between both patch shapes and food quality patterns. Deer selected better diets in blocks than lines. In lines, the herd selected better diets when quality varied between alternate feeders rather than between the two halves of the patch, suggesting a reliance on personal rather than group information. Deer consumed the most at patch centres in all treatments except in blocks with high-tannin centres, but diet selection was poorer in the latter compared to blocks with low-tannin centres. Aggregation at the centre of patches appears to have restricted exploitation of the best food. Predation pressure and/or resource variability may have favoured the evolution of a foraging strategy that prioritizes social cohesion over effective diet selection.

Faced with rapid environmental changes, individuals may express different magnitude and plasticity in their response to a given stressor. However, little is known about the causes of variation in phenotypic plasticity of the stress response in wild populations. In the present study, we repeatedly captured individual roe deer (Capreolus capreolus) from two wild populations in Sweden exposed to differing levels of predation pressure and measured plasma concentrations of stress-induced cortisol and behavioral docility. While controlling for the marked effects of habituation, we found clear between-population differences in the stress-induced cortisol response. Roe deer living in the area that was recently recolonized by lynx (Lynx lynx) and wolves (Canis lupus) expressed cortisol levels that were around 30% higher than roe deer in the human-dominated landscape free of large carnivores. In addition, for the first time to our knowledge, we investigated the stress-induced cortisol response in free-ranging newborn fawns and found no evidence for hypo-responsiveness during early life in this species. Indeed, stress-induced cortisol levels were of similar magnitude and differed between populations to a similar extent in both neonates and adults. Finally, at an individual level, we found that both cortisol and docility levels were strongly repeatable, and weakly negatively inter-correlated, suggesting that individuals differed consistently in how they respond to a stressor, and supporting the existence of a stress-management syndrome in roe deer.

Mammalian browsers can cause ecologically and economically significant damage to important tree species, particularly at the vulnerable seedling stage. Some tree species or particular parts of trees are less preferred as a result of chemical defences - harnessing such defences could reduce the appeal of more preferred trees and thus their loss to browsing. We tested the potential of birch bark extract, a forestry by-product, to protect seedlings of Scots pine Pinus sylvestris from two globally significant browsers: moose Alces alces and red deer Cervus elaphus. We quantified the responses by captive animals to extract application as a function of both the distance between seedlings and whether the extract was applied to all or alternate seedlings. Both moose and red deer consumed pine seedlings less frequently when seedlings were treated with birch bark extract, but their responses differed when only alternate seedlings were treated. At inter-seedling distances equivalent to those used in forestry, red deer browsed untreated seedlings more frequently when alternate seedlings were treated than when none were treated (associational susceptibility), whereas moose browsed untreated seedlings less frequently with treated than untreated neighbours (associational refuge). These neighbourhood effects were not evident at inter-seedling distances three times larger or smaller than those used in forestry. There was also no significant difference in the frequency of browsing on treated seedlings in alternate compared to completely treated arrangements at any inter-seedling distance. Red deer removed significantly less foliage from treated than untreated seedlings once browsed. Browsing by moose followed a similar but non-significant trend. The relative number of untreated to treated seedlings browsed was 2:1 for red deer and 4:1 for moose. Red deer used a finer scale of selection than moose for choosing between seedlings, consistent with their smaller body mass. However, the coarser-scale of selection used by moose resulted in consumption of more untreated relative to treated seedlings. Our study highlights the potential of existing plant defensive chemistry, harvested from forestry by-products, to reduce herbivore damage to tree seedlings. We also demonstrate the need to consider both plant associational effects and the foraging strategies of the dominant herbivores in applying repellents.

The concept of associational plant defenses is widely accepted and implies that an unpalatable plant can protect its neighbors from grazing. We have investigated the new but similar question of whether a part of a plant, for example, the top or bottom, can protect other parts. At the same time, we investigated whether the previously observed selection of the apical shoot and upper leaves of plants is a direct consequence of food quality (the plant vigor hypothesis) or whether there is an innate or learnt foraging pattern behind the observation. In experiments, we used 1 m high artificial trees, made from aspen branches, and measured red deer browsing from the top (above 0.5 m) and bottom (below 0.5 m), with application of condensed tannin to the top or bottom as a proxy for plant part unpalatability. There were four treatments where either none, both, or one part (top or bottom) of the artificial trees had tannin applied. As expected, we found that red deer consumed less from parts with tannin. We also found that a defended top protected an undefended bottom, but we found no evidence for the opposite relationship, which could be explained by foraging behavior. When examining the behavior, we found that adult red deer prefer to start feeding from the top of a plant. We also found that they spent a shorter time feeding on a defended top. This behavior might cause a defended top to protect an undefended bottom. Such directional associational plant defense could be the result of selectivity with limited flexibility and might be more pronounced for mammalian herbivores than for insects, since mammals are bigger in size and more restricted in their head position. An important applied aspect of these results is that when saplings are protected by adding a repellent, for instance in forestry, it might be enough to apply repellent to the tops. On the other hand, according to this directional associational plant defense, protected bottoms will not protect tops, so newly grown apical shoots may need new protection.

Hantaviruses are globally distributed and cause severe human disease. Puumala hantavirus (PUUV) is the most common species in Northern Europe, and the only hantavirus confirmed to circulate in Sweden, restricted to the northern regions of the country. In this study, we aimed to further add to the natural ecology of PUUV in Sweden by investigating prevalence, and spatial and host species infection patterns. Specifically, we wanted to ascertain whether PUUV was present in the natural reservoir, the bank vole (Myodes glareolus) further south than Dalälven river, in south-central Sweden, and whether PUUV can be detected in other rodent species in addition to the natural reservoir. In total, 559 animals were collected at Grimsö (59°43'N; 15°28'E), Sala (59°55'N; 16°36'E) and Bogesund (59°24'N; 18°14'E) in south-central Sweden between May 2013 and November 2014. PUUV ELISA-reactive antibodies were found both in 2013 (22/295) and in 2014 (18/264), and nine samples were confirmed as PUUV-specific by focus reduction neutralization test. Most of the PUUV-specific samples were from the natural host, the bank vole, but also from other rodent hosts, indicating viral spill-over. Finally, we showed that PUUV is present in more highly populated central Sweden.

Background

To understand and reduce the concomitant effects of trapping and handling procedures in wildlife species, it is essential to measure their physiological impact. Here, we examined individual variation in stress levels in non-anesthetized European roe deer (Capreolus capreolus), which were captured in box traps and physically restrained for tagging, biometrics and bio-sampling. In winter 2013, we collected venous blood samples from 28 individuals during 28 capture events and evaluated standard measurements for stress (heart rate, body temperature, neutrophil to lymphocyte ratio, lactate and total cortisol). Additionally, we assessed stress using the immunological tool, Leukocyte Coping Capacity (LCC), a real-time proxy for stress measuring oxygen radical production by leukocytes. Finally, the behavioral response to handling was recorded using a scoring system.

Results

LCC and therefore stress levels were negatively influenced by the time animals spent in the box trap with human presence at the capture site prior to handling. In contrast, none of the classical stress measures, including total cortisol, nor the behavioral assessment, were correlated with the stressor tested (time of human presence prior to handling) and thus did not provide a clear depiction regarding the extent of the animals short-term stress response.

Conclusions

Overall our study verifies the LCC as a strong method to quantify short-term stress reactions in wildlife. Moreover, our results clearly show that human presence at the trapping site prior to handling should be kept to an absolute minimum in order to reduce stress levels.

Personality exists in non-human animals and can impact fitness. There is, however, a shortage of empirical studies in certain areas within the field, and fundamental evolutionary theory on personality remains largely untested. For example, little is known on how variation in personality is maintained over evolutionary time. Theory suggests that fluctuating selection pressures due to spatiotemporal variation in conditions, e.g. food availability, is a possible mechanism and a few studies have shown that the success of different personality types varies with spatiotemporal conditions. However, it remains unknown whether different mechanisms can maintain personality within a species. Here we use a reintroduction programme for the critically endangered European mink (Mustela lutreola) to test whether multiple personality trait domains (boldness, exploration and sociability) affected survival in two different years and islands. This was done through pre-release personality tests and post-release radio-tracking monitoring. Survival was positively correlated with boldness, whereas the relationship with exploration was either negative or positive depending on year/island. The results show a complex relationship between personality and survival and suggest that exploration can be maintained over evolutionary time via spatiotemporal variation in conditions. However, in contrast to exploration, boldness did not vary spatiotemporally and sociability had no impact on survival. This indicates that different personality trait domains might be maintained by different mechanisms. To date, personality has been studied primarily within behavioural sciences, but through empirical findings we highlight the importance of personality also in ecology and conservation biology.