Katarzyna Zajac

Katarzyna Zajac
Polish Academy of Sciences | PAN · Institute of Nature Conservation

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49
Publications
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653
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Publications

Publications (49)
Preprint
The infamous “master manipulators” – intracellular bacteria from the genus Wolbachia – infect a broad range of phylogenetically diverse hosts in terrestrial ecosystems. Wolbachia have important impacts on the ecology and evolution of their hosts with documented effects including induced parthenogenesis, male killing, feminization, and cytoplasmic i...
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The naiads, large freshwater mussels (Unionida), have very long life spans, are large-bodied, and produce thousands to millions of larvae (glochidia) which typically must attach to host fish tissues to metamorphose into a juvenile mussel. Glochidia develop within a female's marsupial gill demibranch, thus their number is restricted by female size....
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The life cycle of unionids is characterized by a obligatory period of larval parasitism on a fish host, any disturbance of which might cause a large-scale decline in the mussel population. Because the probability of fish infestation is so important, we modelled what would happen to a population (in terms of population growth and probability of exti...
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Females of freshwater mussels spawn eggs which, after fertilization, are brooded until the developing larvae reach a stadium ready to infest a fish host in order to complete the obligate parasitic phase of their life. We investigated the duration of the brooding period in the endangered thick-shelled river mussel Unio crassus in two rivers in south...
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1. Post-maturation growth leading to indeterminate growth patterns is widespread in nature. However, its adaptive value is unclear. Life history theory suggests this allocation strategy may be favored by temporal pulses in the intensity of mortality and/or the capacity to produce new tissues. 2. Addressing the origin of indeterminate growth and the...
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Bivalves play an important part in freshwater ecosystems and improve water quality; the thick-shelled river mussel Unio crassus is classified as a bioindicator. Unfortunately, the species is regarded as endangered and is under species protection in the whole of Europe. The reasons for the drastic decline of its populations are: considerable eutroph...
Article
Despite the high taxonomic diversity, wide distribution and important ecosystem functions of snails, their ecology remains obscure, and this can hamper their conservation. Overwintering in the studied population of Vertigo moulinsiana is effective enough to allow the majority of it to survive. The population dynamics of V. moulinsiana is specific,...
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Mussels of the family Unionidae are important components of freshwater ecosystems. Alarmingly, the International Union for Conservation of Nature and Natural Resources Red List of Threatened Species identifies almost 200 unionid species as extinct, endangered, or threatened. Their decline is the result of human impact on freshwater habitats, and th...
Article
What factors determine biome richness: genetic or environmental? Sex, phylogeny, and tolerance indicated by other symbionts (e.g., endosymbionts) or simply is it related to local habitat, especially if the gut biome is considered? To answer these questions, we investigated the gut microbial profile of both sexes of three Unio crassus populations, s...
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Endosymbiotic bacterial species that manipulate host biology, reproduction and mitochondrial genetic diversity have been identified in many metazoans, especially terrestrial arthropods. Until now, the hypothesis that Wolbachia or other bacterial endosymbiont might be absent in mollusks has remained unexplored. We present here preliminary data on ba...
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Although eutrophication of freshwaters is a natural process, the human impact often leads to inland waters becoming overloaded with nutrients, impoverishing many valuable and vanishing habitats, such as floodplain lakes. These changes need to be reversed if the occurrence of endangered aquatic species is to be restored. In this paper we analyse the...
Article
1. We report a large-scale die-off of ca.1/3 of the unionid mussels inhabiting a shallow, naturally eutrophic floodplain lake (Zalew Pińczowski), which took place within the space of just a few days. 2. Mortality was the highest in Pseudanodonta complanata (81%), followed by Unio pictorum (58%), Anodonta cygnea (26%), Unio tumidus (15%) and Anodont...
Article
1. Freshwater mussels are one of the most endangered groups of animals. Translocation is a common conservation measure for protecting them, but the success of this procedure varies widely, and the reasons for failure are frequently unknown. 2. The dispersal and mortality of freshwater mussels was studied using a novel method: radio-tracking of Uni...
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A new large population of the Asian clam Corbicula fluminea (O.F.Müller, 1774) was found within a reach (ca 210 km long) of one of the largest European rivers, the Vistula.The largest population and the largest individuals were found at the outlet of a channel collecting heated water from the cooling process at the Połaniec power station and adjace...
Article
1. Freshwater mussels (Unionoida) are globally threatened. The key to the development of effective conservation strategies for this group is to unravel their complicated life cycle, including the obligatory larva, which parasitizes the external tissues of fish. 2. Artificial infestation was conducted in the following three fish species: Chondrostom...
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We studied shell variation in the thick-shelled river mussel (Unio crassus). Individuals of various sex and age were sampled from two sites of very different character: (1) a rocky channel (the San river) and (2) a fine-sediment channel (the Zborowianka river). Analysed individuals differed significantly between the sampled channels in almost all a...
Article
We applied in vitro techniques in culturing glochidia of the thick-shelled river mussel Unio crassus, seriously threatened European species. Glochidia were freshly isolated from a gravid female. The sterile phase of the cultures was terminated at different time points to assess the optimal length of this phase. We imitated the process of juvenile e...
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Large freshwater mussels (Unionoida) are declining throughout the world. The European bitterling Rhodeus amarus (Bloch, 1782) female spawns its eggs inside the unionids’ shells, where fertilisation and further embryonic development take place; thus its reproduction depends fully on the presence of large freshwater mussels. Unio crassus, previously...
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Freshwater mussels of the Order Unionida provide important ecosystem functions and services, yet many of their populations are in decline. We comprehensively review the status of the 16 currently recognized species in Europe, collating for the first time their life-history traits, distribution, conservation status, habitat preferences, and main thr...
Article
Some bivalve species possess two independent mitochondrial DNA lineages: maternally (F-type) and paternally (M-type) inherited. This phenomenon is called doubly uniparental inheritance. It is generally agreed that F-type mtDNA is typically present in female somatic and gonadal tissues as well as in male somatic tissues, whereas the M-type mtDNA occ...
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Mussels are intermediate hosts of digenean trematodes, but determinants of these infections remain unknown. To address this problem, we collected duck mussels Anodonta anatina in eighteen lakes from northeastern Poland and examined how mussel age, sex, and the encrustation with zebra mussels Dreissena polymorpha and environmental conditions in lake...
Article
Europe's increasing populations of medium-size predators pose a potential threat to freshwater mussels in some regions. Live mussels (Anodonta cygnea) collected from the bottom of Zalew Pinczowski reservoir (S Poland) did not differ in size from shells of individuals predated by otters, but the shells of predated individuals varied in size signific...
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The pearl mussel was abundant in the Sudety Mountains until the late 19th century. No live mussels were found within the present borders of Poland since the early 20th century. In 2006–2007 we did a detailed survey of 50 streams and rivers within the former range of the pearl mussel to verify its current status and assess the habitat conditions. No...
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Basic information on biology, ecology and monitoring methods in Polish populations of Natura2000 protected freshwater snail species, Anisus vorticulus (Troschel, 1834)
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Unio crassus, an endangered freshwater mussel species, inhabits streams with diversified physical structure, subject to frequent changes in channel morphology. It is usually regarded as a sedentary animal, although individual movement has been observed. The hypothesis that adults can use movement in order to actively select a microhabitat was teste...
Article
Unio crassus, an endangered freshwater mussel species, inhabits streams with diversified physical structure, subject to frequent changes in channel morphology. It is usually regarded as a sedentary animal, although individual movement has been observed. The hypothesis that adults can use movement in order to actively select a microhabitat was teste...
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Thick shelled river mussel Unio crassus (included in IUCN Red Data List) is a benthic, filter-feeding animal very susceptible to any changes of water chemistry. In this paper we report on the new sites of this species in the Małopolska region - an area of strong anthropogenic pressure. Physical and chemical parameters have been compared between 8 r...
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The aim of the paper was to find main traits of river ecosystem (river channel morphology, anchorage features and aquatic plants) responsible for occurrence of bivalves from threatened family Unionidae. River channel depth, width, channel slope and sinuosity, substratum type, as well as aquatic plant and bivalve occurrence were studied along 60 tra...
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Zajkc K.: Habitat preferences of swan mussel Anodonta cygnea (Linnaeus 1758)(Bivalvia, Unionidae) in relation to structure and successional stage of floodplain waterbodies. Ekologia (Bratislava), Vol. 21, No. 4, 345-355, 2002. The habitat requirements of swan mussel Anodonta cygnea L. were studied in water bodies on the floodplain of the Nida river...
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The distribution and habitat preferences of the Roman snail (Helix pomatia L.) were studied in the region of Matopolska in 1997-1999. Cluster analysis was used to determine a relationship between the occurrence of snails and different habitat parameters such as habitat type, its naturalness, humidity, plant cover and soil type as well as landscape...
Chapter
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The Kraków-Częstochowa Jura constitutes a structural and functional entity and is an area of great natural value. It has been identified as a site of European importance in the CORINE system. The individual character of this area is determined by geological conditions, specifically geomorphology, and particularly karstic phenomena. The specificity...

Projects

Projects (4)
Project
Description from https://confremus.eu/ : "Freshwater bivalves are a large, diverse and important group, since they can dominate the biomass of many ecosystems. Furthermore, they are among the world’s most imperiled taxonomic groups. Freshwater bivalves provide crucial ecosystem functions and services such as water purification and nutrient cycling, thus can be used as nature-based tools for improving ecosystem functions and services as well as representing important indicators of ecosystem health. Through the international cooperation of scientists from multiple disciplines, this Action will aim to fully understand the biodiversity crisis being faced by Europe’s freshwater mussels and develop evidence-based solutions to halt the loss of their biodiversity and ecosystem services." https://www.cost.eu/actions/CA18239/#tabs|Name:overview
Archived project
- To remove barriers to the migration of aquatic organisms in the river - To select a free migration corridor in the river and to develop the conditions for its functioning - To restore the population connectivity of the amphibian Bombina variegata and the bivalve Unio crassus in the valley - To restore the river’s riparian and channel vegetation - To raise awareness of the problems addressed in the project.