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

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

Senescence as a trade-off between successful land colonisation and longevity: critical review and analysis of a hypothesis

Background Most common terrestrial animal clades exhibit senescence, suggesting strong adaptive value of this trait. However, there is little support for senescence correlated with specific adaptations. Nevertheless, insects, mammals, and birds, which are the most common terrestrial animal clades that show symptoms of senescence, evolved from clades that predominantly did not show symptoms of senescence. Thus, we aimed to examine senescence in the context of the ecology and life histories of the main clades of animals, including humans, and to formulate hypotheses to explain the causes and origin of senescence in the major clades of terrestrial animals. Methodology We reviewed literature from 1950 to 2020 concerning life expectancy, the existence of senescence, and the adaptive characteristics of the major groups of animals. We then proposed a relationship between senescence and environmental factors, considering the biology of these groups of animals. We constructed a model showing the phylogenetic relationships between animal clades in the context of the major stages of evolution, distinguishing between senescent and biologically ‘immortal’ clades of animals. Finally, we synthesised current data on senescence with the most important concepts and theories explaining the origin and mechanisms of senescence. Although this categorisation into different senescent phenotypes may be simplistic, we used this to propose a framework for understanding senescence. Results We found that terrestrial mammals, insects, and birds show senescence, even though they likely evolved from non-senescent ancestors. Moreover, secondarily aquatic animals show lower rate of senescence than their terrestrial counterparts. Based on the possible life histories of these groups and the analysis of the most important factors affecting the transition from a non-senescent to senescent phenotype, we conclude that aging has evolved, not as a direct effect, but as a correlated response of selection on developmental strategies, and that this occurred separately within each clade. Adoption of specific life history strategies could thus have far-reaching effects in terms of senescence and lifespan. Conclusions Our analysis strongly suggests that senescence may have emerged as a side effect of the evolution of adaptive features that allowed the colonisation of land. Senescence in mammals may be a compromise between land colonisation and longevity. This hypothesis, is supported by palaeobiological and ecological evidence. We hope that the development of new research methodologies and the availability of more data could be used to test this hypothesis and shed greater light on the evolution of senescence

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

Wybrane problemy eksploatacyjne bystrzy o zwiększonej szorstkości (stopni-ramp) w aspekcie ich projektowania i funkcjonalności biologicznej

W pracy przedstawiono wybrane problemy budowy i eksploatacji bystrzy o zwiększonej szorstkości zwanych inaczej stopniami-rampami, skupiając się głównie na trzech obszarach tematycznych: stanowisku górnym bystrza, stanowisku dolnym bystrza, płycie spadowej z głazami oraz gurtach obiektu. Podano wnioski co do prawidłowego projektowania bystrzy, jak i przykłady z praktyki inżyniersko-wykonawczej oraz badań. Zwrócono uwagę na możliwości zasiedlenia bystrza przez bezkręgowce wodne, a także na konieczność zapewnia w projekcie ciągłości ekologicznej w niskich stanach wody

Back from the Brink: The Holocene History of the Carpathian Barbel <i>Barbus carpathicus</i>

<div><p>As a result of specific adaptations and habitat preferences strongly rheophilic fish species may show high levels of endemism. Many temperate rheophilic fish species were subjected to a series of range contractions during the Pleistocene, and then successfully expanded during the Holocene, colonising previously abandoned areas. The Carpathian barbel (<i>Barbus carpathicus</i> Kotlík, Tsigenopoulos, Ráb et Berrebi 2002) occurs in the montane streams in three basins of the main Central European rivers in the northern part of the Carpathian range. We used genetic variation within 3 mitochondrial and 9 microsatellite loci to determine a pattern of postglacial expansion in <i>B. carpathicus</i>. We found that overall genetic variation within the species is relatively low. Estimate of time to the most recent common ancestor (tMRCA) of mitochondrial sequences falls within the Holocene. The highest levels of genetic variation found in upper reaches of the Tisa river in the Danube basin suggest that glacial refugia were located in the south-eastern part of the species range. Our data suggest that the species crossed different watersheds at least six times as three genetically distinct groups (probably established in different expansion episodes) were found in northern part of the species range. Clines of genetic variation were observed in both the Danube and Vistula basins, which probably resulted from subsequent bottlenecks while colonizing successive habitats (south eastern populations) or due to the admixture of genetically diverse individuals to a previously uniform population (Vistula basin). Therefore, <i>B. carpathicus</i> underwent both demographic breakdowns and expansions during the Holocene, showing its distribution and demography are sensitive to environmental change. Our findings are important in the light of the current human-induced habitats alterations.</p> </div

Spatial distribution of clusters detected in an assignment test performed in TESS.

<p>Solid green line – border between clusters when K = 2, dashed line – borders of the 3^rd cluster for K=3.</p