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Background: Forest trees, particularly at a young age in afforestation, are susceptible to bark gnawing by herbivorous rodents such as voles. Few preventive measures for vole damage exist, although mowing to control herbaceous vegetation is often suggested. However, no empirical evidence supports the claim that mowing prevents or inhibits rodent damage to seedlings in a forest ecosystem. We examined the effects of single mowing applications on rodent population dynamics and the amount of damage they cause. The study was conducted at 34 randomly selected European beech forest plantations in Poland, with half manually mowed in late summer. In each plantation, we monitored the population dynamics of small rodents every 2 months from December 2019 to April 2021, and/or measured the level of damage to tree saplings monthly., Results: The amount of damage followed a clear seasonal pattern with peaks in late autumn ranging from 0 to 40% of saplings per plantation. Mowing did not alter the pattern of population dynamics of small rodents (including voles and mice) on the plantations, nor did it reduce sapling damage caused by rodents. Additionally, herbaceous vegetation cover had no significant effect on the damage intensity., Conclusions: Our results indicate that mowing is ineffective in preventing tree damage by small rodents in forest plantations; therefore, we do not recommend it as a forestry practice. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Oxidative stress (OS) and impaired immune function (IF) have been proposed as key physiological costs of reproduction. The relationship between OS and IF remains unresolved, particularly in long-living iteroparous species. We studied physiological markers of maintenance (OS, IF markers) in lactating, post-lactating and non-lactating females of edible dormice-a long-living rodent. We predicted the OS balance and IF to be compromised by lactation, especially in older females expected to face stronger trade-offs between life functions. We found that the age predictor (body size) correlated negatively with white blood cell level (WBC), positively with neutrophils to lymphocytes ratio and had no effect on OS markers. Oxidative damage markers (reactive oxygen metabolites (ROMs); but not antioxidant capacity) and body size-adjusted WBC were the lowest in lactating, higher in post-lactating and the highest in non-lactating females. Body size/age did not affect this correlation suggesting a similar age-independent allocation strategy during reproduction in this species. The path analysis testing the causal relationship between ROMs and WBC revealed that IF is more likely to affect OS than vice versa . Our study indicates the trade-off between crucial life functions during reproduction and suggests that immunosuppression reduces the risk of OS; therefore, mitigating oxidative costs of reproduction.

Climate change causes far-reaching disruption in nature, where tolerance thresholds already have been exceeded for some plants and animals. In the short term, deer may respond to climate through individual physiological and behavioral responses. Over time, individual responses can aggregate to the population level and ultimately lead to evolutionary adaptations. We systematically reviewed the literature (published 2000-2022) to summarize the effect of temperature, rainfall, snow, combined measures (e.g., the North Atlantic Oscillation), and extreme events, on deer species inhabiting boreal and temperate forests in terms of their physiology, spatial use, and population dynamics. We targeted deer species that inhabit relevant biomes in North America, Europe, and Asia: moose, roe deer, wapiti, red deer, sika deer, fallow deer, white-tailed deer, mule deer, caribou, and reindeer. Our review (218 papers) shows that many deer populations will likely benefit in part from warmer winters, but hotter and drier summers may exceed their physiological tolerances. We found support for deer expressing both morphological, physiological, and behavioral plasticity in response to climate variability. For example, some deer species can limit the effects of harsh weather conditions by modifying habitat use and daily activity patterns, while the physiological responses of female deer can lead to long-lasting effects on population dynamics. We identified 20 patterns, among which some illustrate antagonistic pathways, suggesting that detrimental effects will cancel out some of the benefits of climate change. Our findings highlight the influence of local variables (e.g., population density and predation) on how deer will respond to climatic conditions. We identified several knowledge gaps, such as studies regarding the potential impact on these animals of extreme weather events, snow type, and wetter autumns. The patterns we have identified in this literature review should help managers understand how populations of deer may be affected by regionally projected futures regarding temperature, rainfall, and snow., (Global Change Biology© 2024 The Author(s). Global Change Biology published by John Wiley & Sons Ltd.)

Maintenance metabolism as the minimum energy expenditure needed to maintain homeothermy (a high and stable body temperature, T b ), reflects the magnitude of metabolic machinery and the associated costs of self-maintenance in endotherms (organisms able to produce heat endogenously). Therefore, it can interact with most, if not all, organismal functions, including the behavior-fitness linkage. Many endothermic animals can avoid the costs of maintaining homeothermy and temporally reduce T b and metabolism by entering heterothermic states like torpor, the most effective energy-saving strategy. Variations in BMR, behavior, and torpor use are considered to be shaped by food resources, but those conclusions are based on research studying these traits in isolation. We tested the effect of ecological contexts (food availability and predation risk) on the interplay between the maintenance costs of homeothermy, heterothermy, and exploration in a wild mammal-the yellow-necked mouse. We measured maintenance metabolism as basal metabolic rate (BMR) using respirometry, distance moved (exploration) in the open-field test, and variation in T b (heterothermy) during short-term fasting in animals captured at different locations of known natural food availability and predator presence, and with or without supplementary food resources. We found that in winter, heterothermy and exploration (but not BMR) negatively correlated with natural food availability (determined in autumn). Supplementary feeding increased mouse density, predation risk and finally had a positive effect on heterothermy (but not on BMR or exploration). The path analysis testing plausible causal relationships between the studied traits indicated that elevated predation risk increased heterothermy, which in turn negatively affected exploration, which positively correlated with BMR. Our study indicates that adaptive heterothermy is a compensation strategy for balancing the energy budget in endothermic animals experiencing low natural food availability. This study also suggests that under environmental challenges like increased predation risk, the use of an effective energy-saving strategy predicts behavioral expression better than self-maintenance costs under homeothermy., Competing Interests: No actual or potential conflicts of interest are declared by the authors., (© 2024 The Author(s). Ecology and Evolution published by John Wiley & Sons Ltd.)

Metabolic physiology and animal behaviour are often considered to be linked, positively or negatively, according to either the performance or allocation models. Performance seems to predominate over allocation in natural systems, but the constraining environmental context may reveal allocation limitations to energetically expensive behaviours. Habitat disturbance, such as the large-scale fire that burnt wetlands of Biebrza National Park (NE Poland), degrades natural ecosystems. It arguably reduces food and shelter availability, modifies predator-prey interactions, and poses a direct threat for animal survival, such as that of the wetland specialist root vole Microtus oeconomus. We hypothesized that fire disturbance induces physiology-behaviour co-expression, as a consequence of changed environmental context. We repeatedly measured maintenance and exercise metabolism, and behavioural responses to the open field, in a root voles from post-fire and unburnt locations. Highly repeatable maintenance metabolism and distance moved during behavioural tests correlated positively, but relatively labile exercise metabolism did not covary with behaviour. At the same time, voles from a post-fire habitat had higher maintenance metabolism and moved shorter distances than voles from unburnt areas. We conclude there is a prevalence of the performance mechanism, but simultaneous manifestation of context-dependent allocation constraints of the physiology-behaviour covariation after disturbance. The last occurs at the within-individual level, indicating the significance of behavioural plasticity in the context of environmental disturbance., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

With the recent return of large carnivores to forest ecosystems, an important issue for forest owners and managers is how large predators influence the behaviour of their natural prey and, consequently, cervid browsing pressure on forest regeneration. To investigate this issue, we analysed deer pressure on Scots pine and European beech plantations in northern Poland's ecosystems with and without permanent wolf populations. Two characteristics were used to describe deer browsing patterns in plantations: distance from the forest edge (spatial pattern of browsing) and number of saplings browsed (browsing intensity). Beech saplings were more intensively browsed by deer compared to pine saplings. In a forest ecosystem not inhabited by wolves, spatial variation in browsing patterns on small-sized beech plantations was the same between the edge and the center. In contrast, browsing pressure by deer was greater at the edges on large-sized pine plantations. The presence of wolves reduced deer browsing on beech and increased browsing on pine saplings. In addition, deer foraging behaviour changed in large-sized pine plantations, and browsing pressure increased only in the central areas of the plantations. We assume that the presence of wolves in a forest landscape is an important factor that alters browsing pressure on the youngest stands and their spatial pattern, and that this may be a major factor in stand regeneration, especially in small forest patches., (© 2023. Springer Nature Limited.)

Accumulation of silica (Si) by plants can be driven by (1) herbivory pressure (and therefore plant-herbivore interactions), (2) geohydrological cycles, or (3) a combination of (1) and (2), with (1-3) possibly affecting Si concentration with a 1-year delay.To identify the relative significance of (1-3), we analyzed the concentration of Si in fibrous tussock sedge ( Carex appropinquata ), the population density of the root vole ( Microtus oeconomus ), and the groundwater level, over 11 years.The largest influence of autumn Si concentration in leaves (Si leaf ) was on the level of the current-year groundwater table, which was positive and accounted for 13.3% of its variance. The previous year's vole population density was weakly positively correlated with Si leaf , and it alone explained 9.5% of its variance.The only variable found to have a positive, significant effect on autumn Si concentration in rhizomes (Si rhiz ) was the current-year spring water level, explaining as much as 60.9% of its variance.We conclude that the changes in Si concentration in fibrous tussock sedge are predominantly driven by hydrology, with vole population dynamics being secondary.Our results provide only partial support for the existence of plant-herbivore interactions, as we did not detect the significant effects of Si tussock concentration on the vole density dynamics. This was mainly due to the low level of silicification of sedges, which was insufficient to impinge herbivores.Future studies on plant-herbivore interactions should therefore aim at disentangling whether anti-herbivore protection is dependent on threshold values of herbivore population dynamics. Furthermore, studies on Si accumulation should focus on the effect of water-mediated Si availability., Competing Interests: The authors declare no conflict of interest., (© 2021 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Background: Global warming and drying have markedly enhanced in most forests the risk of fires across the world, which can affect the taxonomic and functional composition of key tree-associated organisms such as ectomycorrhizal (ECM) fungi. The present study was conducted to characterise the alterations in the extent of root ECM colonisation, the ECM fungal communities, and their exploration types ( i.e. , indicator of ECM soil foraging strategies) in regenerated pines within a burned site as compared with an unburned site (five years after the fire event) in the Forest District Myszyniec, Poland., Methods: To assess the ECM fungal communities of burned and control sites, soil soil-root monoliths were collected from the study sites in September 2019. A total of 96 soil subsamples were collected for soil analysis and mycorrhizal assessment (6 trees × 2 sites × 4 study plots × 2 microsites (north and south) = 96 subsamples)., Results: The percentage of root ECM colonisation was significantly lower in the burned site in comparison with the unburned (control) site. However, the ECM species richness did not differ between the control and burned sites. The identified ECM species in both sites were Imleria badia, Thelephora terrestris, Russula paludosa , R. badia , R. turci , R. vesca , Lactarius plumbeus, Phialocephala fortinii , and Hyaloscypha variabilis . The most frequent species in the burned and control sites were I. badia and T . terrestris, respectively. The relative abundances of contact, medium-distance smooth and long-distance exploration types in the burned site were significantly different from the control site, dominated by the medium-distance exploration type in both sites. The abundance of the long-distance exploration type in the burned site was markedly greater (27%) than that of the control site (14%), suggesting that the fire event had favoured this ECM foraging strategy. The results demonstrated that the fire led to reduced ECM colonisation of Scots pine trees in the burned site whereas the species richness was not affected, which can be attributed to degrees of fire-resistance in the ECM species, survival of ECM propagules in deeper soil layers, and/or continuous entry of spores/propagules of the ECM fungi from the adjacent forests via wind, water run-off or animals., Competing Interests: The authors declare there are no competing interests., (©2021 Olchowik et al.)

Background: Deer pressure on forest regeneration constitutes a serious problem in commercial forests in the northern hemisphere due to the increase in deer populations. However, other drivers, such as climate, landscape structure and the level of human activity, have a strong influence on deer pressure. The direct, density-related impacts of ungulates on forest regeneration have been well studied, but there is limited empirical evidence related to the indirect factors mentioned above. We conducted a field experiment in three forest divisions in Poland to evaluate the role of a common element of human infrastructure, i.e. small, unpaved forestry roads. Additionally, we assessed the modifying effect of visibility driven by vegetation cover and forage availability., Results: The proximity of unpaved roads affected deer habitat use and foraging behaviour, and limited browsing pressure on regenerating forests. Low visibility and higher winter forage availability increased the probability of tree browsing. We observed different responses to roads in two deer species: red deer avoided roads, while roe deer browsed in the vicinity of roads., Conclusions: A typical forest network of unpaved roads creates a landscape of fear for red and roe deer, and limits browsing pressure on regenerating forests due to the changes in deer habitat use, activity patterns and foraging behaviour. Knowledge of the factors influencing browsing pressure can help to spatially optimise the application of protective measures for tree seedlings., (© 2020 Society of Chemical Industry.)

Masting-temporally variable seed production with high spatial synchrony-is a pervasive strategy in wind-pollinated trees that is hypothesized to be vulnerable to climate change due to its correlation with variability in abiotic conditions. Recent work suggests that aging may also have strong effects on seed production patterns of trees, but this potential confounding factor has not been considered in previous times series analysis of climate change effects. Using a 54 year dataset for seven dominant species in 17 forests across Poland, we used the proportion of seed-producing trees (PST) to contrast the predictions of the climate change and aging hypotheses in Abies alba, Fagus sylvatica, Larix decidua, Picea abies, Pinus sylvestris, Quercus petraea, and Quercus robur. Our results show that in all species, PST increased over time and that this change correlated most strongly with stand age, while the standardized precipitation-evapotranspiration index, a measure of drought, contributed to temporal trends in PST of F. sylvatica and Q. robur. Temporal variability of PST also increased over time in all species except P. sylvestris, while trends in temporal autocorrelation and among-stand synchrony reflect species-specific masting strategies. Our results suggest a pivotal role of plant ontogeny in driving not only the extent but also variability and synchrony of reproduction in temperate forest trees. In a time of increasing forest regrowth in Europe, we therefore call for increased attention to demographic effects such as aging on plant reproductive behavior, particularly in studies examining global change effects using long-term time series data., (© 2020 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

Background: Supplementary feeding is a widespread but controversial practice in game management. While many studies have been conducted on this issue, there is limited empirical evidence on how feeding affects damage caused by wildlife. In this context, the present study focused on the effect of artificial winter feeding on tree damage in three mountain regions in Poland., Results: The presence of additional winter food did not increase tree damage caused by deer in any region, as expected. Moreover, we observed that additional feeding mitigated forest damage in one region, where the highest level of deer impact had occurred. However, in this mountain region, the most important factor was elevation, which was used to classify additional feeding practice as efficient or inefficient. In the two other study regions, we did not observe any effect of supplementary feeding., Conclusions: Additional winter supplementary feeding can reduce damage caused by deer in forest stands, but only in areas with high deer pressure. Moreover, feeders should be situated in locations > 600 m above sea level in our study area. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Masting, the highly variable production of synchronized large seed crops, is a common reproductive strategy in plant populations. In wind-pollinated trees, flowering and pollination dynamics are hypothesized to provide the mechanistic link for the well-known relationship between weather and population-level seed production. Several hypotheses make predictions about the effect of weather on annual pollination success. The pollen coupling hypothesis predicts that weather and plant resources drive the flowering effort of trees, which directly translates into the size of seed crops through efficient pollination. In contrast, the pollination Moran effect hypothesis predicts that weather affects pollination efficiency, leading to occasional bumper crops. Furthermore, the recently formulated phenology synchrony hypothesis predicts that Moran effects can arise because of weather effects on flowering synchrony, which, in turn, drives pollination efficiency. We investigated the relationship between weather, airborne pollen, and seed production in common European trees, two oak species (Quercus petraea and Q. robur) and beech (Fagus sylvatica) with a 19-yr data set from three sites in Poland. Our results show that warm summers preceding flowering correlated with high pollen abundance and warm springs resulted in short pollen seasons (i.e., high flowering synchrony) for all three species. Pollen abundance was the best predictor for seed crops in beech, as predicted under pollen coupling. In oaks, short pollen seasons, rather than pollen abundance, correlated with large seed crops, providing support for the pollination Moran effect and phenology synchrony hypotheses. Fundamentally different mechanisms may therefore drive masting in species of the family Fagacae., (© 2017 by the Ecological Society of America.)

The increase in the deer population observed in recent decades has strongly impacted forest regeneration and the forest itself. The reduction in the quality of raw wood material, as a consequence of deer-mediated damage, constitutes a significant burden on forest owners. The basis for the commencement of preventive actions in this setting is the understanding of the populations and behaviors of deer in their natural environment. Although multiple studies have been carried out regarding this subject, only a few suggested topography as an important factor that may influence the distribution and intensity of deer-mediated damage. The detailed terrain models based on LiDAR data as well as the data on damage caused by deer from the State Forests database enabled thorough analyses of the distribution and intensity of damage in relation to land form in this study. These analyses were performed on three mountain regions in Poland: the Western Sudety Mountains, the Eastern Sudety Mountains, and the Beskidy Mountains. Even though these three regions are located several dozen to several hundred kilometers apart from each other, not all evaluated factors appeared common among them, and therefore, these regions have been analyzed separately. The obtained results indicated that the forest damage caused by deer increased with increasing altitude above 1000 m ASL. However, much larger areas of damage by deer were observed at elevations ranging from 401 to 1000 m ASL than at elevations below 400 m ASL. Moreover, the locations of damage (forest thickets and old stands) indicated that red deer is the species that exerts the strongest pressure on forest ecosystems. Our results show the importance of deer foraging behavior to the structure of the environment., Competing Interests: The authors have declared that no competing interests exist.

The trajectories of postglacial range expansions, the occurrence of lineage patches and the formation and maintenance of secondary contact between lineages may mostly reflect neutral demographic processes, including density blocking, that may leave long-lasting genetic signatures. However, a few studies have recently shown that climate may also play a role. We used red deer, a large, mobile herbivore that is assumed to be sensitive to climate change, to test hypotheses of possible selection on the mitochondrial DNA cytochrome b gene (mtDNA cytb) and competitive and/or density-blocking (using mtDNA control region). We searched for a possible link between the phylogeographic structure and abiotic climatic variables. Finally, we tested for isolation by distance and isolation by environment and assessed the impact of human-mediated translocations on the genetic structure of red deer. Our analysis of 30 red deer populations in Poland using the mtDNA control region (N = 357) and cytochrome b (N = 50) markers not only confirmed the presence of the Western and South-Eastern lineages of the species but also indicated the presence of a previously unnoticed, rare relic haplotype that grouped together C. e. italicus from Italy (the Mesola deer). No significant signs of positive selection were detected for the mtDNA cytb gene in the studied red deer. However, a significant signal for purifying selection was found in our study that may explain the narrowness of the contact zone because gene flow between the Western and South-Eastern lineages should drive relatively strong mito-nuclear incompatibilities. MtDNA control region differentiation among red deer populations in Poland correlated with different abiotic climatic variables. Strikingly, the southernmost ice sheet limits during the Elsterian was the most important factor, and it explained the largest amount of variation. However, neither isolation by distance (IBD) nor isolation by environment (IBE) were recorded, and a very limited impact of human translocations was evident. The above-mentioned results suggest that in contemporary red deer populations in Poland, the phylogeographic pattern is well preserved, and long-term processes (density and/or competitive blocking) still play a major role., Competing Interests: The authors have declared that no competing interests exist.

Alek Rachwald, Tim Bradford, Zbigniew Borowski, and Paul A. Racey (2016) The habitat preferences of the soprano pipistrelle Pipistrellus pygmaeus and the common pipistrelle Pipistrellus pipistrellus living in sympatry, were investigated in north east Scotland, using bat detector transects. Bat flight, foraging and social activity in natural birch woodland was compared with that in managed non-native coniferous woodland. Each area consists of riparian habitat, meadow-forest ecotone and dense forest. The activity of bats was highest in riparian habitat, then meadow, and lowest in dense woodland. P. pygmaeus was more abundant than P. pipistrellus in both areas, although in managed coniferous woodland only narrowly so (43.7% of all recorded bat flights, compared to 40.0% for common pipistrelle). In natural birch woodland, meadow habitat was most preferred by P. pipistrellus , and there was no significant difference between the use of riparian and woodland habitats, whereas in coniferous woodland, riparian habitat was most preferred. P. pygmaeus in both sites preferred riparian habitat, then meadow and forest least of all. The foraging activity of soprano pipistrelles was higher in birch than in coniferous woodland, whereas for the common pipistrelle, it was more evenly distributed. In both sites the lowest number of feeding buzzes was recorded in dense forest. In both study areas social calls were recorded, but many more for P. pygmaeus than for P. pipistrellus , especially in birch woodland. Soprano pipistrelle is a specialist species, focused mostly on riparian habitat, whereas common pipistrelle shows more generalistic behaviour. High number of social calls recorded near the waterbodies could suggest, that such habitat partitioning could be caused also by competitive behaviour.

Introgressive hybridization is a widespread evolutionary phenomenon which may lead to increased allelic variation at selective neutral loci and to transfer of fitness-related traits to introgressed lineages. We inferred the population genetic structure of the European roe deer (Capreolus capreolus) in Poland from mitochondrial (CR and cyt b) and sex-linked markers (ZFX, SRY, DBY4 and DBY8). Analyses of CR mtDNA sequences from 452 individuals indicated widespread introgression of Siberian roe deer (C. pygargus) mtDNA in the European roe deer genome, 2000 km from the current distribution range of C. pygargus. Introgressed individuals constituted 16.6% of the deer studied. Nearly 75% of them possessed haplotypes belonging to the group which arose 23 kyr ago and have not been detected within the natural range of Siberian roe deer, indicating that majority of present introgression has ancient origin. Unlike the mtDNA results, sex-specific markers did not show signs of introgression. Species distribution modelling analyses suggested that C. pygargus could have extended its range as far west as Central Europe after last glacial maximum. The main hybridization event was probably associated with range expansion of the most abundant European roe deer lineage from western refugia and took place in Central Europe after the Younger Dryas (10.8-10.0 ka BP). Initially, introgressed mtDNA variants could have spread out on the wave of expansion through the mechanism of gene surfing, reaching high frequencies in European roe deer populations and leading to observed asymmetrical gene flow. Human-mediated introductions of C. pygargus had minimal effect on the extent of mtDNA introgression., (© 2014 John Wiley & Sons Ltd.)

In many species, dominance increases a male's mating success via intrasexual competition and/or female choice. The level of androgen hormones, mainly testosterone (T), the intensity of scent marking and body mass are traits that are known to be linked to mammalian male social rank. Recently, however, it has been noted that this link between male dominance and the aforementioned traits in natural free-living populations is not universal and does not exist in some species. That is why we tested the hypothesis of whether a male's social rank is related to the expression of T, scent-marking and his body mass. We conducted the study on the promiscuous rodent species, root voles (Microtus oeconomus), which originated from a natural population (wild-born). These tests provided support for the following conclusions: (1) the social status of a male root vole is partly related to his level of testosterone; (2) the highest T level was observed in subdominant males; (3) T levels proved to be independent of male body mass; (4) marking frequency was not dependent on a male's social status nor their body mass; and (5) the mean body mass of dominant, subdominant and subordinate individuals was similar. Our results indicate that in natural free-living populations, the link between the T levels and dominance behaviour of root vole males is ambiguous. Moreover, there is no link between the social status and the intensity of scent-marking. We therefore conclude that in this species, male marking intensity cannot be used as an indicator of social rank., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Significant inter-individual variation in the rate of animal metabolism is a widespread phenomenon that has started to accumulate general interest. Here we follow recent calls to focus on linkage between the variation in energy metabolism and animal personality. By using wild caught root voles as a study species, we examined the relationship between the behavioral patterns (assessed in open field test) and resting metabolic rate (RMR), both of which are known to show large individual differences and intra-individual consistency in voles. Our results showed only a weak relationship between personality traits and metabolism, since the most parsimonious model (according to AICc) explaining RMR included only body mass and season as factors (explaining 84.8% of variation in RMR). However, the next two alternative models (within ΔAICc=2) also included the personality trait reflecting proactive behaviors (PC1) in addition to body mass, sex and season (85.2 and 85.8% of RMR variance explained, respectively). In all, our study does not provide compelling support for recent ideas of close linkage between behavior and metabolism. Still, our study highlights that even in the case of wild caught individuals, when behavior and metabolism often carry effects of both intrinsic and extrinsic conditions, the potential metabolic effects of varying energetically costly behaviors cannot be neglected., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Although drive counts are frequently used to estimate the size of deer populations in forests, little is known about how counting methods or the density and social organization of the deer species concerned influence the accuracy of the estimates obtained, and hence their suitability for informing management decisions. As these issues cannot readily be examined for real populations, we conducted a series of 'virtual experiments' in a computer simulation model to evaluate the effects of block size, proportion of forest counted, deer density, social aggregation and spatial auto-correlation on the accuracy of drive counts. Simulated populations of red and roe deer were generated on the basis of drive count data obtained from Polish commercial forests. For both deer species, count accuracy increased with increasing density, and decreased as the degree of aggregation, either demographic or spatial, within the population increased. However, the effect of density on accuracy was substantially greater than the effect of aggregation. Although improvements in accuracy could be made by reducing the size of counting blocks for low-density, aggregated populations, these were limited. Increasing the proportion of the forest counted led to greater improvements in accuracy, but the gains were limited compared with the increase in effort required. If it is necessary to estimate the deer population with a high degree of accuracy (e.g. within 10% of the true value), drive counts are likely to be inadequate whatever the deer density. However, if a lower level of accuracy (within 20% or more) is acceptable, our study suggests that at higher deer densities (more than ca. five to seven deer/100 ha) drive counts can provide reliable information on population size.

There are numerous studies showing that predation risk may change different aspects of the behavior of prey, such as habitat use, activity pattern, and foraging. Prey should exhibit the strongest antipredatory response against their most deadly predator. Small mustelids are considered the most important mammalian predators of voles. Nevertheless, there is no general agreement as to whether strong antipredatory reactions exist in natural free-living populations of voles. Here, we studied the field vole Microtus agrestis spatial reaction to high predation risk from small mustelids in the breeding (August) and nonbreeding (October) seasons under natural conditions. Voles were exposed to a caged weasel (Mustela nivalis) and a stoat (Mustela erminea), as well as to the odors of these predators. The reactions of 30 field voles were monitored with radiotelemetry. The field voles were found to display antipredator reactions that varied with season. In the breeding period, in response to predation risk, voles reduced locomotory activity and daily-range size, whereas in the nonbreeding period they did not. Changes in home range position were similar for control and treatment voles, in both the breeding and nonbreeding periods. The results indicate that mustelid predators modify the spatial behavior of small rodents in natural conditions depending on season. This might be a reflection of differences in state-dependent responses to predation from sexually active or inactive individuals. This suggests that the basic antipredatory reaction of voles under high predation risk from small mustelids limits their locomotory activity.

We used 10 microsatellite loci to determine the mating system and male reproductive success in a natural population of the root vole (Microtus oeconomus). By genotyping 21 females and their 111 offspring (5.28+/-0.27 S.E. pups per female), we found evidence for multiple paternity in 38% of the litters sired by two or three males. Paternity was not significantly skewed away from the null expectation of equal proportions of offspring sired in any of the multiple-sired litters, and the most successful male fathered between 40% and 60% of the pups in a litter. The results indicate that promiscuity is a common mode of reproduction, consistent with the previous classification of the mating system based on the spatial structure of the root vole population.

The new locality of Ixodes apronophorus Schulze, 1924 in Biebrza National Park, Poland is recorded. The study was conducted in open wet-meadow habitat (Caricetum appropinquatae), in April 2007. The small mammals were caught in live-traps placed at permanent trap stations. The ectoparasites were collected from the fur using combing out method. The adult female, nymphs and larva of Ixodes apronophorus were found, feeding on the common shrew Sorex araneus.