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In the first year's data of the 10th Finnish National Forest Inventory (2005–2008) 533 active and 178 abandoned ant mounds were found yielding 4.2 mounds ha-1. We found 11 species: Formica rufa, F. polyctena, F. aquilonia, F. lugubris, F. pratensis, F. exsecta, F. fennica, F. pressilabris, F. forsslundi, F. suecica and F. uralensis. Five species occurred throughout the country, and four were restricted to the south. We found species-specific associations with either mineral soils or mires, with forest site type and with tree-canopy openness. Low fertility decreased the occurrence of polygynous species with large worker force, and sun-exposition was favourable for species with smaller colonies presumably because only large worker force enables metabolic thermoregulation of nests. Forest fragmentation and increased amount of edge habitats favourable for colony founding have presumably increased nest density whereas drainage of mires has reduced the amount of habitat of three species since the 1950s.
To date, digestive flexibility has been studied in dozens of vertebrate species. However, practically all of these works has ignored the importance of intraspecific physiological variability across populations inhabiting different habitats. Here, we compare the digestive tract gross morphology of three populations of the Andean toad (Bufo spinulosus), inhabiting along an altitudinal gradient and feeding on different food items. Results support a core prediction of digestive theory, i.e., intestinal length increases in parallel with the content of indigestible material in the natural diet. The present study suggest how variation in the abiotic environment associated with altitude (e.g., temperature, water availability, soil quality) can change biotic conditions (e.g., vegetation cover, prey availability), affect feeding behavior of individuals (e.g., width and composition of trophic niche), and, ultimately, individuals' digestive features (e.g., gut morphology).
The population structure of the Baltic salmon (Salmo salar) specific clade of Gyrodactylus salaris was studied using mitochondrial and nuclear DNA markers across a gradient of historical coadaptation. In the Onega and Ladoga lakes, the salmon was near to eliminating the parasite: just 5 of 548 inspected salmon juveniles carried a small number of parasites. In the northern Baltic Tornio River, G. salaris was observed as non-pathogenic in 23% of 765 fish. The population of naïve anadromous salmon in the Keret' River (White Sea) had almost perished after the parasite was imported from Lake Onega in 1992. The parasite clones defined by mtDNA were strongly spatially structured (FST = 0.548 in Keret'; FST = 0.484 in Tornio), suggesting competitive interactions via host defense. The prevalence and clonal structuring of G. salaris were concordant with the host resistance predicted from the suggested 132 000 years of common phylogeographic history in the Baltic refugia.
Anthropogenic changes have strongly influenced the European landscape. In the last 50 years electric power-line networks have become a conspicuous part of that landscape. From the outset it was known that these lines and their support structures would cause fatalities in the white stork, Ciconia ciconia. From a long-term (1983–2006) study in Poland, we analysed breeding performance in stork nests on four types of structure (chimneys, roofs, trees and electricity poles). Whilst the numbers of nests on both electricity poles and chimneys have increased, there was no significant difference among the four structures in terms of breeding success. Since 1998, over 100 electricity poles in this white-stork breeding area have been modified to include a platform designed to accommodate a stork nest. A comparison between the annual means of nests on electricity poles with and without platforms did not reveal any significant differences in breeding success. However, closer examination of the nests transferred to platforms revealed a slight drop in chick productivity in the year following platform addition, which, however, became significantly higher in the subsequent year. Thus the transfer of nests to platforms appears to have only a short-term adverse effect and may be beneficial in the long run.
Game species exploitation usually causes an increase in their distribution, further from their own dispersal potential, but we know too little about the ecological effects that these human-induced expansions may produce. The realized niche of the red deer was analyzed by means of habitat suitability modelling in the present study. Two populations inhabiting different geographic areas have been distinguished according to their origin, one is native to the study area and the other was translocated as a result of human hunting interests. Translocated red deer showed strong distributional overlap with the native Iberian ibex. However, a comparative analysis of the potential distribution of native red deer and Iberian ibex populations did not yield a significant niche overlap. Thus, we conclude that the observed niche overlap between the Iberian ibex and the red deer in the study area would not have taken place without human intervention. We discuss these results in the light of biological invasions and native species translocation programmes, and conclude that human-induced range expansion of native species should be regarded as a specific case of invasive species.
We studied the epigenetic variability and epigenetic distance of raccoon dogs from seven European localities and the species' Amursk area of origin. The studies were based on 24 non-metric traits in 1046 skulls. Native raccoon dogs from the Amursk region showed the same low level of epigenetic variability as the European populations, giving no indication of a founder effect or inbreeding. Epigenetic distances between raccoon-dog populations were generally high. The German regions formed a separate cluster with a rather high epigenetic distance to the Finnish-Polish group. This indicates different migration lines of the species. The native raccoon dogs of the Amursk region were completely separate from the European populations as a consequence of the distinct reproductive isolation of about 60 years, as well as an effect of the colonisation and migration history of the species.
Plant responses to mammalian herbivores can be manifold. Browsing by large mammals such as moose may change plant growth and morphology, which, in turn, will change the food quality and availability for e.g. invertebrate herbivores sharing the same forage plant. Furthermore, the intensity and timing of herbivory may affect plant responses and future herbivore attack. In a field experiment, we tested whether simulated summer browsing and natural winter browsing by moose affects growth and morphology of birch Betula pendula, and whether possible changes had effects on abundance and defoliation by herbivorous invertebrates. The simulated summer browsing treatment was applied in two intensities (50% and 100% defoliation of long shoots) during two different periods of the growth season (mid-June and mid-July). Simulated summer browsing delayed the timing of budburst, reduced height and diameter growth and resulted in reduced defoliation by invertebrate herbivores indicating an induced defence. Winter browsing by moose reduced diameter growth, leaf biomass of short shoots but increased height growth, the abundance of aphids and defoliation by insect herbivores. The effects of herbivory on the timing of budburst, leaf biomass of long and short shoots and the abundance of aphids were more pronounced when the birches were both browsed in winter and artificially stripped. The timing of the artificial leaf stripping treatment was important for nearly all tested variables. Concluding, summer and winter browsing by moose can have opposing or additive effects on plant morphology and growth. Therefore, also indirect effects of mammalian herbivory on invertebrate communities feeding on the same plant may differ, depending on the browsing intensity, the season of browsing and even the timing of browsing within the same season.
In order to test how emotions affect individual neutral facial expressions and the reliability of humans to read these expressions, we photographed faces of 25 women wearing clothes in which they felt attractive, unattractive, or comfortable while expressing an emotionally neutral face. Men found the faces of women in attractive clothes the most attractive, whereas the faces of women in comfortable and unattractive clothes were ranked as intermediate and least attractive, respectively, even though the clothes were not visible in the photographs. Our results demonstrate that despite very subtle effects, the emotional state of women is perceived by men and that the two sexes are concordant on the signal sent and received. We show a close connection between exterior attributes, confidence, and how a person is perceived by others.
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