Expansion of water chestnut in a small dam reservoir: from pioneering colony to dense floating mat

Background and Purpose: This manuscript reports on the rapid spread of water chestnut in a shallow dam reservoir. The water chestnut is a critically endangered plant in Poland. Materials and Methods: From 2008 to 2016 during the vegetation season we investigated the distribution of water chestnut in the Rzeszów dam reservoir.Results: The colony has grown from sparse individual plants which probably appeared around 2005, to a dense floating mat of plants with the total area of over 14 ha today. Recently water chestnut has also appeared in all shallow parts of the reservoir with weak water flow. Conclusions: Taking into consideration the dynamic expansion of the water chestnut, it can be assumed that in the near future this species may control many parts of the Rzeszów reservoir, while in others it can be displaced by reeds. It is highly probable then that the total area of water chestnut patches will decrease, rather than increase.</p

Biomechanical responses to changes in friction on a clay court surface

Objectives: To examine the influence of clay court frictional properties on tennis players’ biomechanical response. Design: Repeated measures Methods: Lower limb kinematic and force data were collected on sixteen university tennis players during 10 x 180° turns (running approach speed 3.9 ± 0.20 m.s-1) on a synthetic clay surface of varying friction levels. To adjust friction levels the volume of sand infill above the force plate was altered (kg per m2 surface area; 12, 16 and 20 kg.m-2). Repeated measures ANOVA and Bonferroni’s corrected alpha post-hoc analyses were conducted to identify significant differences in lower limb biomechanics between friction levels. Results: Greater sliding distances (ŋp2= 0.355, p = 0.008) were observed for the lowest friction condition (20 kg.m-2) compared to the 12 and 16 kg.m-2 conditions. No differences in ankle joint kinematics and knee flexion angles were observed. Later peak knee flexion occurred on the 20 kg.m-2 condition compared to the 12 kg.m-2 (ŋp2 = 0.270, p = 0.023). Lower vertical (ŋp2 = 0.345, p = 0.027) and shear (ŋp2 = 0.396, p = 0.016) loading rates occurred for the 20 kg.m2 condition compared to the 16 kg.m2. Conclusions: Lower loading rates and greater sliding distances when clay surface friction was reduced suggests load was more evenly distributed over time reducing players’ injury risks. The greater sliding distances reported were accompanied with later occurrence of peak knee flexion, suggesting longer time spent braking and a greater requirement for muscular control increasing the likelihood of fatigue

The effects of brown trout on salamander larvae habitat selection: a predator-avoidance strategy

Predatory fish can have a major impact on aquatic amphibian assemblages. Knowledge on the influence of habitat heterogeneity on predator-prey dynamics is extensive, but not much is published on how the habitat structure influences the co-occurrence of brown trout (Salmo trutta m. fario L., 1758) and fire salamander (Salamandra salamandra (L., 1758)). I examined the microhabitat distribution of salamander larvae in relation to the presence of brown trout and stream morphology, hypothesizing that larval salamanders will increase their habitat use in the presence of trout to avoid predation. Fish and salamanders were sampled with a electroshocker, in 62 instream habitat patches. In the stream zone populated by brown trout, larval salamanders avoided high quality habitats such as pools, whereas they strongly preferred them in the fishless zone (in pools their densities were ~10 times lower than in riffles). Brown trout mainly occupied deeper pools. The co-occurrence of fire salamander larvae with trout suggests the presence of an effective predator-avoidance strategy. The predator-avoidance response and habitat use pattern decreased interspecific overlap, leading to the use of different instream spaces. Heterogeneous habitats enable habitat partitioning between salamander larvae and brown trout, which means that the natural characteristics of streams promote coexistence between fish and amphibians.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Reakcje bezkręgowców bentosowych na akumulację drobnoziarnistego osadu w potoku górskim

Gospodarka leśna często wiąże się z niszczeniem pokrywy glebowej, a drogi leśne ułatwiają dopływ wyerodowanej gleby do potoków i ich zamulanie. Celem pracy była ocena stanu ekologicznego potoku narażonego na zamulanie na podstawie składu zespołu bezkręgowców bentosowych. Badaniami objęto potok Tym (Pogórze Przemyskie), mający charakter cieku górskiego, z dość dużym spadkiem koryta i kamienisto-żwirowym dnem. Zmiany w korycie potoku związane były z wynikającą z prac leśnych akumulacją drobnoziarnistego osadu na dnie. Wyznaczono 4 stanowiska badawcze: dwa w strefie akumulacji osadów i dwa na odcinkach niezamulonych. Oceniano parametry morfologiczne koryta, fizyko-chemiczne wody oraz pobierano próby makrozoobentosu. Dopływ drobnoziarnistego osadu, który pokrywał dno potoku, skutkował wyraźnym zaburzeniem składu fauny bezkręgowej. Pogorszyły się warunki siedliskowe dla bezkręgowców związanych z podłożem kamienistym i szybko płynącą wodą, tj. dla widelnic, jętek i chruścików. Natomiast na dnie pokrytym osadem mineralnym licznie były larwy Chironomidae i skąposzczety

The relationship between video games and literature in modern visual culture

Praca skupia się na zależnościach między grami wideo a literaturą. Przedstawiono możliwe źródła rozwijającej się współcześnie kultury wizualnej. Omówiono rolę gier wideo w obecnych czasach. Skupiono się na zjawiskach łączących gry z literaturą, takie jak literatura grywalna czy zjawisko novelization, a także opisane zostały modele narracyjne wykorzystywane w grach wideo.The main concern of this thesis is the relationship between video games and literature. The sources of developing modern visual culture have been described as well as the role of video games nowadays. Phenomena of video games being connected to literature such as playable poetry or novelization have beed discussed. Narrative models that are used in video games have been enumerated

Correspondence between Krystyna Skwarko and Krystyna and Czeslaw Bednarczyk

Praca zawiera korespondencję prowadzoną w latach 1971–1982 przez Krystynę Skwarko, przebywającą na emigracji w Nowej Zelandii nauczycielkę i pisarkę, oraz Krystynę i Czesława Bednarczyków, właścicieli emigracyjnego wydawnictwa Oficyna Poetów i Malarzy. Korespondencja opatrzona jest wstępem omawiającym najważniejsze zagadnienia, takie jak życiorys i twórczość Skwarko czy działalność Bednarczyków, a także notą edytorską i przypisami.This thesis contains correspondence from 1971–1982 between Krystyna Skwarko, emigrant teacher and writer residing in New Zealand after World War II, and Krystyna and Czeslaw Bednarczyk, owners of emigrant publishing house Poets’ and Painters’ Press. The correspondence is provided with an introduction describing the most important issues, such as Skwarko’s biography and work and Bednarczyks’ activity, and also with an editorial note and footnotes

Double origin of the racer goby (Babka gymnotrachelus) in Poland revealed with mitochondrial marker. Possible implications for the species alien/native status

In mid-1990s racer goby, Babka gymnotrachelus, penetrated to the Vistula and Western Bug rivers in Poland through the canal connecting the Baltic and the Black Sea basins, namely the Vistula and Dnieper drainages. In early 2000s, the species was reported from Polish section of the Strwiąż River that is an affluent of the Dniester River that drains to the Black Sea basin. According to the Polish legislation, the racer goby has been enlisted in as an alien invasive species that may pose threat to local biota. Our analysis of the mtDNA cytochrome b diversity revealed that the Vistula/Western Bug and Strwiąż populations are different genetic units. First one originated from the Dnieper River, while the second derives from the Dniester River. According to the results of mismatch analysis, both are in the stage of demographic and spatial expansion. The haplotype frequencies in population from the Vistula/Western Bug differ significantly from those in the source population in Dnieper, suggesting founder effect, possibly due to human-mediated introduction of low number of individuals. On the other side, the population in Strwiąż does not differ in structure from the one in Dniester, providing a hint towards spontaneous range expansion. Interpretation of our results in light of historical data lead to the conclusion that presence of racer goby in Strwiąż was probably overlooked in previous, spatially limited, studies. Thus, in Strwiąż the species should not be treated as alien, contrary to its status in the Vistula drainage. This double origin of racer goby populations in Poland creates a peculiar situation for national legislation procedures as one population is alien and invasive, while the other one is not. In light of our findings, the population from Strwiąż should be recognised as a special case. Steps should be undertaken to raise public awareness to prevent translocation of the gobies between the rivers to prevent deterioration of the evolutionarily isolated genetic pools of the Dnieper and of the Dniester basins. Our results illustrate the need for case studies upon genetic population structure, following appearance of new species in previously unoccupied water bodies, even on local scale. </p