On the Lebesgue measure of Li-Yorke pairs for interval maps

We investigate the prevalence of Li-Yorke pairs for $C^2$ and $C^3$ multimodal maps $f$ with non-flat critical points. We show that every measurable scrambled set has zero Lebesgue measure and that all strongly wandering sets have zero Lebesgue measure, as does the set of pairs of asymptotic (but not asymptotically periodic) points. If $f$ is topologically mixing and has no Cantor attractor, then typical (w.r.t. two-dimensional Lebesgue measure) pairs are Li-Yorke; if additionally $f$ admits an absolutely continuous invariant probability measure (acip), then typical pairs have a dense orbit for $f \times f$. These results make use of so-called nice neighborhoods of the critical set of general multimodal maps, and hence uniformly expanding Markov induced maps, the existence of either is proved in this paper as well. For the setting where $f$ has a Cantor attractor, we present a trichotomy explaining when the set of Li-Yorke pairs and distal pairs have positive two-dimensional Lebesgue measure.Comment: 41 pages, 3 figure

Dynamics of Genistella sagittalis [L.] Gams in Hegi population in the Kozienicka Primeval Forest in the period of 1997-2007

A new stand of rare in the Polish flora subshrub of Fabaceae family − Genistella sagittalis was recorded in 1997 in the area of Kozienicki Landscape Park and subjected to monitoring. The analysis covers the observation period from 1997 to 2007. On the basis of phytosociological relevés a negative effect of such factors as undergrowth overshading and interspecies competition on condition of Genistella sagittalis population was stated. The species demonstrates expansive tendencies in insolated habitats of little undergrowth cover. The population seems to be stabile and is not endangered at present

Globe flower Trollius europaeus L. in forest and forest edge communities in the northern part of the Poludniowopodlaska Lowland

The distribution of Trollius europaeus in the northern part of the Południowopodlaska Lowland was described and a phytosociological study made of the localities where it was present between 2010 and 2012. The condition of all sites where T. europaeus was historically present was also verified. These field studies reveal that the number of sites of occurrence and the abundance of T. europaeus populations have rapidly diminished over recent years. Only 15 populations of the species in the vicinity of 7 sites were confirmed. Trollius europaeus is usually considered a species characteristic of moist meadows of ordo Molinietalia and in the plant community type, Polygono bistortae-Trollietum. In the northern part of the Po³udniowopodlaska Lowland, no meadow sites containing Trollius europaeus still remain according to our survey. All the confirmed stands are situated in deciduous forests of class Querco-Fagetea (Tilio-Carpinetum and Potentillo albae-Quercetum) and moist forest edge communities of ordo Glechometalia. The disappearance of all meadow populations is mainly considered a result of intensification of the agricultural use of these habitats. We suggest that the category of threat to Trollius europaeus is increased on the regional list from VU to EN, and consolidated with further monitoring and active protection of stands where it is present

State of the flora of Biele nature reserve [Sokolow Podlaski Forest District] after 20 years of conservation

The state of the flora of the Biele nature reserve (Sokołów Podlaski Forest District) after 20 years of nature conservation was assessed. Only one species noted in 1989 was not confirmed at present, whereas 38 newcomers were observed. Most of them (30 species) prefer light and half−light/light conditions and are mainly related to non−forest communities. Frequency of synanthropic species is still very low (2.4%) and no anthropophytes were noted in the reserve. All protected and endangered plants, eg. Trollius europaeus, Gladiolus imbricatus, Dactylorhiza fuchsii, except of Carex umbrosa, still occur within its borders. Active protection of Trollius europaeus and Gladiolus imbricatus by removal of brushwood was suggested

The station of the hop tree (Ptelea trifoliata L. ssp. trifoliata) in forests of the Wyszkow Forest District

This research was carried out on two experimental plots located in the Rymanów and Nawojowa forest districts. In the second and fifth year after planting, at three and six years of age respectively, survival and height of 25 beech progenies of selected stands were measured. Furthermore, we show the effect of beech origin and growth environment (significant ‘provenance × block’ and ‘provenance × test plot’ interactions). Beeches from both experimental plots differed significantly in growth and survival and this difference increased with tree age. The highest provenance heritability was obtained for the tree height after two years of growth in Rymanów. In Nawojowa, the heritability of beech survival reached zero after five years of growth. An evaluation of the stability of beech provenances (genotypes) in terms of survival and height under the habitat conditions of our experimental plots was done using the Finlay and Wilkinson method. The beech provenances of 469–Nawojowa and 452–Lesko (regional standard) were included as a stable basis for reference. A high degree of stability and high average values for the characteristics investigated indicate highprogeny quality within these stands

Vegetation of the 'Mierzwice' nature reserve and its protection

The ‘Mierzwice’ nature reserve (forest district 206b, c and d of the Sarnaki Forest Inspectorate), situated in the area of the Podlaski Przełom Bug Landscape Park, is one of the most valuable natural assets of the central Bug river valley. The 12.98 ha reserve was established in 2010 to aid protection of the stand of xerothermic vegetation and its surrounding deciduous forest. In total, eight plant associations were identified within the reserve: Geranio-Peucedanetum cervariae, Geranio-Anemonetum sylvestris, Geranio-Trifolietum alpestris, Trifolio medii-Agrimonietum, Rubo fruticosi- Prunetum, Rhamno-Cornetum sanguinei, Potentillo albae-Quercetum and Tilio cordatae-Carpinetum betuli. Furthermore, 23 protected and 31 endangered species were found in the reserve including the following examples: Cephalanthera rubra, Thesium ebracteatum, Cypripedium calceolus, Gentiana cruciata, Anemone sylvestris, Cimicifuga europaea, Viola rupestris, Crepis praemorsa, Asperula tinctoria, Stachys recta, Laserpitium latifolium. Over the last few years, a regression of the species diagnostic number for thermophilous oak forests and xerothermic grasslands has been observed as a result of succession and expansion of Calamagrostis epigejos. Active protection of xerothermic vegetation such as uprooting of trees and bushes, regular grazing or mowing has been suggested in order to prevent the expansion of Calamagrostis epigejos

The Twinflower (Linnaea borealis L.) in the northern part of the Poludniowopodlaska Lowland

Linnaea borealis, the twinflower, is considered a critically endangered species in the Południowopodlaska Lowland. The disappearance of the twinflower is mainly caused by habitat changes resulting from forest management, but also light deficiency due to the increase in canopy cover and growth of the shrub layer (processes of succession). The aim of the paper is to present the actual distribution and phytosociological characteristics of L. borealis in the northern part of the Południowopodlaska Lowland. In this region, only three out of ten known areas of occurrence (Werchliś, Serpelice, Grala-Dąbrowizna) have endured to the present day. The twinflower occurs in pine forest, Peucedano-Pinetum, and mixed forest, Querco roboris-Pinetum, communities. A decrease in the ground cover of twinflower populations was observed in all existing twinflower locations. Although the area covered by the Linnaea borealis population in Werchliś increased tenfold during the last 20 years (from about 200 m2 in 1993 to 1970 m2 in 2013), its cover-abundance according to the Braun-Blanquet scale decreased from 5 to 3. The increase in the area covered by the twinflower population together with the accompanying decrease in cover-abundance is probably not a manifestation of species dynamics but rather a response to disadvantageous environmental changes (growth of canopy cover and shrub layer). Progressive light reduction can initiate the process of fragmentation of a population. A decrease in the cover-abundance of the L. borealis population (from 4 to 2) was also observed in Serpelice. Its area was reduced to half of its original size due to anthropogenic destruction of this location. In the third region, Grala-Dąbrowizna, also the negative effects of competitive species (e.g. Vaccinium myrtillus, V. vitis-idaea) are considered