Within-crown pattern of ecophysiological features in leaves ofAcer campestre andCarpinus betulus

The crowns of mature sample trees ofAcer campstre L. andCarpinus betulus L. growing in a closed forest served for the determination of water content in leaves, of specific leaf area and stomatal density. Three layers were taken into account, the position of the leaf with regard to the exposure of the particular portion of the crown, leaf insertion within the limb, and changes in the course of the growing period.     

Paternity cues and mating opportunities: what makes fathers good?

Human males provide facultative paternal investment to their offspring; that is, the male care is not necessary for the survival of his offspring. It is expected that the degree of male investment (1) increases with growing paternity certainty, (2) increases when investment increases the survival and later reproductive prospect of offspring and (3) declines when there are opportunities to mate with multiple females. Using a large sample of adult offspring and their fathers (n = 245), we first investigated the role of two factors possibly involved in the assessment of paternity and subsequently regulating the level of paternal investment: (a) father–child facial resemblance and (b) assortative mating for eye colour. Second, because mating opportunities are inversely related to paternal investment, we also investigated how male facial attractiveness (a cue of mate opportunities) correlates with paternal investment. In line with paternal investment theory, male investment positively correlated with offspring facial resemblance. However, paternal investment were neither higher among blue-eyed couples, nor there were preferences of blue-eyed men to marry with blue-eyed women. Moreover, father facial attractiveness was unrelated to paternal investment. These results indicate that resemblance between offspring and their fathers still plays an important role in paternal investment decision later in offspring’s life.     

Ecology and distribution of <Emphasis Type="Italic">Tephroseris longifolia</Emphasis> subsp. <Emphasis Type="Italic">moravica</Emphasis> in relation to environmental variation at a micro-scale

Tephroseris longifolia subsp. moravica is an endemic endangered taxon of European importance. Within the nine recently known populations it occurs in very specific site conditions of ecotone habitats. In our contribution, we try to quantify its realized niche with regard to the measured components of its biotic and abiotic environment. The main aim was to assess the importance of spatial environmental variation on taxon occurrence and performance and to relate the obtained ecological information to data on taxon abundance and demography. Possible reasons of taxon rarity are discussed, too. Comparison of plot pairs indicated that plots containing the taxon had deeper soil and higher soil Na and Mg contents than plots without it. They also contained higher number of species, especially forbs. Several soil parameters were positively correlated with taxon size and density while light parameters played minor role. Negative correlations between cover of vascular plants, especially grasses and taxon size and density suggest its reduced competitive ability. Vascular plant-based ecological indicator values were set for light (6), temperature (5), continentality (4), moisture (5), soil reaction (7) and nutrients (5). The studied sites differed in topography, soil characteristics (pH, soil Na, K, Ca, P and NH₄) and cover of herb litter. Size of taxon populations was negatively related to their finite rate of increase which varied between 1.25 and 2.04 and was most sensitive to demographic parameters related to growth. We conclude, that the studied taxon is not strictly stenotopic as the ranges of several environmental variables were rather wide. We suppose, that the narrow limits of recent taxon occurrence are consequences of its low competitive ability and demographic processes related to germination and seedling establishment. The differing requirements of its ontogenetic stages (seedlings and generative individuals) may define the final limits of its small-scale distribution.     

First videotaped infanticide in the common pochard Aythya ferina

A growing body of literature suggests that infanticide is common in a variety of animals. However, most reports are concerned with infanticide by males and these evidences are often indirect or questionable. Here we describe the first videotaped non-parental infanticide by a female common pochard (Aythya ferina) which killed one conspecific duckling. Our observation does not suggest that this attack was caused by a high density of breeding pairs as was found for other ducks (resource competition hypothesis). We speculate that infanticide in this particular case might be adaptive because a reduced number of ducklings in the pond decreased the vulnerability to predation by raptors.