Les conséquences sanitaires et environnementales de la pollution atmosphérique sont devenues au cours des dernières décennies un des problèmes majeurs de notre société. Sensibilisée à cette problématique, la région Nord Pas-de-Calais a été l'une des premières régions à soutenir et à valoriser la biosurveillance végétale de la qualité de l'air. Les travaux scientifiques réalisés dans le cadre de cette thèse ont pour objectif d'étudier les phénomènes d'accumulation et les impacts des composés organiques volatils (COV) chez les bryophytes. Articulées autour de deux axes, les recherches menées visaient à étudier, d'une part, l'accumulation des benzène, toluène, ethylbenzène et xylènes (BTEX), d'autre part, des effets au niveau cellulaire, du benzène chez Tortula ruralis, par l'analyse des variations de l'expression de biomarqueurs de stress oxydant. Des expérimentations complémentaires in situ , sur le littoral dunkerquois, et en conditions contrôlées ont permis d'établir des phénomènes d'équilibre des concentrations en BTEX entre notre modèle végétal et l'air. In situ, les teneurs en BTEX chez les mousses sont fortement conditionnées par les paramètres météorologiques, et principalement la force des vents. De plus, les concentrations atmosphériques en particules PM10 favoriseraient l'accumulation des BTEX chez la mousse. Mais d'une manière générale, les mousses n'accumulent pas les BTEX de façon corrélée aux teneurs dans l'atmosphère. Concernant l'expression des biomarqueurs de stress oxydant, des variations naturelles des paramètres biologiques mesurés sont observées chez la mousse. Ces variations seraient liées à la nature poïkilohydrique des mousses, leur capacité de reviviscence et aux aptitudes qu'elles ont développées pour résister aux variations de leur état d'hydratation. Ainsi, les biomarqueurs de stress oxydant souvent recherchés dans les études d'écotoxicologie, ne seraient pas adaptés pour l'étude des effets chez les bryophytes terrestres.

<p>Rich fens are an important, but threatened, habitat type in the boreal landscape. In this thesis I have examined responses of rich fen vascular plants and bryophytes after drainage and restoration. </p><p>The effects of drainage on the rich fen flora were observed in a long time study and the responses were rapid and drastic. During an initial stage a rapid loss of brown mosses was observed, followed by increases of sedges and early successional bryophytes, and later by an expansion of dominants. Initial effects of hydrological restoration showed that rewetting can promote re-establishment of an ecologically functional rich fen flora, but has to be combined with other treatments, such as mowing or surface disturbance. </p><p>After restoration, re-establishment of locally extinct species may be hampered by dispersal limitations. To test if reintroductions could help to overcome dispersal limitations I performed transplantation studies with four common rich fens bryophytes to a rewetted site. The results showed that the species were able to establish, and that survival and growth were promoted by desiccation protection and liming. </p><p>I further examined competition among three of the most common bryophytes in natural boreal rich fens that usually occur mixed in a mosaic pattern but show small but important microtopographical niche separation. The results indicate similar competitive abilities among the species, and no case of competitative exclusion occurred. The results help to explain the coexistence of these species under natural conditions with microtopographic variation and repeated small scale natural disturbances. </p><p>Restoring a functional flora in drained rich fens is a complex task, which requires understanding of underlying causes of substrate degradation in combination with suitable restoration measures. The thesis suggests how the results can be used in practical restoration work, and also stresses the need for monitoring of restoration experiments over longer time. </p>

The aim of the present paper is to analyze the curricula for secondary schools in terms of mosses and subsequently prepare a botanical excursion to the NNL Borečský Hill with appropriate didactic materials. Textbooks were compared according to several criteria - the frequency of species of mosses, visual aid, information on the ecology and significance of mosses to ecosystem and human well-being, ideas on field trips and work activities. Topics relating to the planned excursion were selected from the Framework Education Programme. At first, the paper summarizes information about the selected location NNL Borečský Hill which I visited in August 2012 and February 2013. Then an exploration and evaluation of botanical sites follow. There are eight designated sites where the students would perform set tasks. The Chapter: Excursion Proposal contains educational materials created for the excursion - characteristics of selected plant species, characteristic species of bryophytes listed in the field guide, the field guide to bryophytes used on location as well as during laboratory work, route guide for teachers, student worksheets. The materials were tested by students in laboratory work in March 2013 and during the postponed excursion (due to bad weather) in April 2013. The results of the verification are...

<p>U&nbsp; radu&nbsp; je&nbsp; analizirana&nbsp; brioflora&nbsp; Fru&scaron;ke&nbsp; gore.&nbsp; Cilj istraživanja bio je&nbsp; utvrđivanje diverziteta, distribucije, uslova mikrostani&scaron;ta i strukture zajednica mahovina na&nbsp; različitim&nbsp; tipovima&nbsp; stani&scaron;ta&nbsp; na&nbsp; Fru&scaron;koj&nbsp; gori. Takođe,&nbsp; jedan&nbsp; od&nbsp; ciljeva&nbsp; je&nbsp; bio&nbsp; i&nbsp; testiranje&nbsp; i optimizacija&nbsp; metode&nbsp; za&nbsp; kvantitativna&nbsp; uzorkovanja briofita&nbsp; na&nbsp; različitim&nbsp; tipovima&nbsp; stani&scaron;ta.&nbsp; Terenska istraživanja su vr&scaron;ena u periodu 2013-2017 godine. Za<br />potrebe florističkih istraživanja terenska uzorkovanja su&nbsp; vr&scaron;ena&nbsp; metodom&nbsp; transekta&nbsp; na&nbsp; 120&nbsp; lokaliteta&nbsp; na području&nbsp; Fru&scaron;ke&nbsp; gore.&nbsp; Za&nbsp; testiranje&nbsp; i&nbsp; optimizaciju metoda&nbsp; za&nbsp; kvantitativna&nbsp; briolo&scaron;ka&nbsp; uzorkovanja kori&scaron;ćene&nbsp; su&nbsp; različite&nbsp; varijante&nbsp; metoda&nbsp; &bdquo;kvadrata&ldquo; (metod ugneždenih kvadrata za prizemnu briofloru i metod&nbsp; postavljanja&nbsp; mikroplotova&nbsp; na&nbsp; različitoj udaljenosti&nbsp; za&nbsp; epifitsku&nbsp; briofloru).&nbsp; Odgovarajuće metode&nbsp; su&nbsp; odabrane&nbsp; na&nbsp; osnovu&nbsp; kriva&nbsp; minimum areala&nbsp; i&nbsp; kriva&nbsp; sličnosti&nbsp; (eng.&nbsp; species-area&nbsp; curve, similarity&nbsp; area&nbsp; curve).&nbsp; Odgovarajuće&nbsp; metode&nbsp; su primenjene za dalja uzorkovanja u ovom istraživanju. Na pojedinim lokalitetima (&scaron;umska i livadska stani&scaron;ta) vr&scaron;eno je merenje nekoliko ekolo&scaron;kih parametara (pH zemlji&scaron;ta&nbsp; i&nbsp; kore&nbsp; drveta,&nbsp; vlažnost&nbsp; zemlji&scaron;ta, temperatura zemlji&scaron;ta, pokrovnost stelje, pokrovnost<br />zeljastih vaskularnih biljaka, udaljenost od potoka u &scaron;umskim stani&scaron;tima i udaljenost &scaron;umskih ekosistema na&nbsp; livadskim&nbsp; stani&scaron;tima)&nbsp; u&nbsp; cilju&nbsp; utvrđivanja&nbsp; uticaja merenih&nbsp; ekolo&scaron;kih&nbsp; parametara&nbsp; na&nbsp; diverzitet&nbsp; i distribuciju briofita.&nbsp; Briofitske zajednice su utvrđene na&nbsp; različitim&nbsp; tipovima&nbsp; stani&scaron;ta&nbsp; i&nbsp; podloge&nbsp; uz&nbsp; pomoć &bdquo;label&nbsp; propagating&nbsp; community&nbsp; detection&ldquo;&nbsp; analize.Rezultati&nbsp; ovog&nbsp; istraživanja&nbsp; su&nbsp; pokazali&nbsp; da&nbsp; je&nbsp; Fru&scaron;ka<br />gora područje koje se odlikuje visokim diverzitetom briofita&nbsp; i&nbsp; ukupno&nbsp; je&nbsp; zabeleženo&nbsp; 235&nbsp; briofitskih taksona (na osnovu literaturnih podataka i terenskih istraživanja).&nbsp; 73&nbsp; taksona&nbsp; briofita&nbsp; je&nbsp; prvi&nbsp; put zabeleženo&nbsp; na&nbsp; području&nbsp; Fru&scaron;ke&nbsp; gore.&nbsp; Od&nbsp; ukupnog<br />broja&nbsp; taksona,&nbsp; 11%&nbsp; je&nbsp; pod&nbsp; nekim&nbsp; stepenom ugroženosti ili zakonske za&scaron;tite. Metoda mikrocenoze se&nbsp; pokazala&nbsp; kao&nbsp; najadekvatniji&nbsp; metod&nbsp; za kvantitativna&nbsp; uzorkovanja&nbsp; prizemnih&nbsp; briofita&nbsp; (sa minimalnom adekvatnom veličinom kvadrata 0.5x0.5 m&nbsp; u&nbsp; &scaron;umskim&nbsp; odnosno&nbsp; 1x1&nbsp; m&nbsp; na&nbsp; livadskim stani&scaron;tima). Za epifitske briofite, kao najadekvatnija se&nbsp; pokazale&nbsp; metoda&nbsp; postavljanja&nbsp; mikroplotova dimenzija&nbsp; 10x10&nbsp; cm&nbsp; sa&nbsp; sve&nbsp; četiri&nbsp; strane&nbsp; stabla&nbsp; na međusobnoj udaljenosti od 20 cm. Struktura stani&scaron;ta ima&nbsp; značajno&nbsp; veći&nbsp; uticaj&nbsp; na&nbsp; diverzitet&nbsp; prizemnih briofita&nbsp; u&nbsp; &scaron;umskim&nbsp; stani&scaron;tima&nbsp; u&nbsp; odnosu&nbsp; na karakteristike&nbsp; zemlji&scaron;ta,&nbsp; dok&nbsp; je&nbsp; na&nbsp; livadskim<br />stani&scaron;tima zabeležen obrnut slučaj.&nbsp; Najveći uticaj na diverzitet epifitskih briofita ima visina na stablu kao i tip forofite. Na istraživanom području je detektovano devet&nbsp; zajednica&nbsp; u&nbsp; prizemnoj&nbsp; brioflori&nbsp; &scaron;umskih stani&scaron;ta;&nbsp; &scaron;est&nbsp; epifitskih&nbsp; zajednica;&nbsp; pet&nbsp; zajednica&nbsp; na livadskim&nbsp; stani&scaron;tima;&nbsp; četiri&nbsp; zajednice&nbsp; na&nbsp; trulim deblima&nbsp; i&nbsp; panjevima;&nbsp; 10&nbsp; zajednica&nbsp; na&nbsp; stenama&nbsp; i kamenju;&nbsp; četiri&nbsp; zajednice&nbsp; u&nbsp; potocima.&nbsp; Dobijeni rezultati&nbsp; predstavljaju&nbsp; građu&nbsp; za&nbsp; dalja&nbsp; briolo&scaron;ka istraživanja, kako floristička tako i ekolo&scaron;ka, i dopunu flore Srbije.</p> / <p>In&nbsp; this research, the bryophyte flora of Fru&scaron;ka gora Mountain was analyzed. The aim of this&nbsp; research was to determine the diversity, distribution, microhabitat conditions&nbsp; and&nbsp; community&nbsp; structure&nbsp; of&nbsp; bryophytes on different types of habitats on Fru&scaron;ka Gora. Also, one of the goals was testing and optimization of the method for&nbsp; quantitative sampling&nbsp; of bryophytes on different types of habitats. Field research was&nbsp; &nbsp; carried out&nbsp; in&nbsp; the&nbsp; period&nbsp; 2013-2017.&nbsp; For&nbsp; the&nbsp; purposes&nbsp; of floristic research, field sampling was carried out using the&nbsp; transect&nbsp; method&nbsp; at&nbsp; 120&nbsp; localities.&nbsp; Different variants of the &quot;quadrat&quot; method (method of nested quadrats&nbsp; for terrestrial bryophytes&nbsp; and the method of&nbsp; placing&nbsp; microplots&nbsp; at&nbsp; different&nbsp; distances&nbsp; for&nbsp; the epiphytic&nbsp; byphytes)&nbsp; were&nbsp; used&nbsp; for&nbsp; testing&nbsp; and optimization of methods for quantitative&nbsp; bryophyte sampling. Appropriate methods were selected on the basis&nbsp; species-area&nbsp; curve&nbsp; and&nbsp; similarity-area&nbsp; curve. Appropriate&nbsp; methods&nbsp; have&nbsp; been&nbsp; applied&nbsp; to&nbsp; further sampling in this study. On some localities (forest and meadow habitats) several&nbsp; environmental parameters (pH&nbsp; of&nbsp; soil&nbsp; and&nbsp; bark&nbsp; of&nbsp; wood,&nbsp; soil&nbsp; moisture,&nbsp; soil temperature,&nbsp; roof&nbsp; cover,&nbsp; coverage&nbsp; of&nbsp; herbaceous vascular&nbsp; plants,&nbsp; distance&nbsp; from&nbsp; the&nbsp; stream&nbsp; in&nbsp; forest habitats&nbsp; and&nbsp; distance&nbsp; of&nbsp; forest&nbsp; ecosystems&nbsp; in meadow&nbsp; habitats)&nbsp; were&nbsp; measured&nbsp; in&nbsp; order&nbsp; to determine their&nbsp; impact&nbsp; on&nbsp; the&nbsp; diversity&nbsp; and distribution&nbsp; of&nbsp; bryophytes.&nbsp; Bryophyte&nbsp; communities were&nbsp; identified&nbsp; on&nbsp; different&nbsp; substrates&nbsp; and&nbsp; habitat types&nbsp; using&nbsp; &quot;label&nbsp; propagating&nbsp; community detection&quot;&nbsp; analysis.&nbsp; The&nbsp; results&nbsp; of&nbsp; this&nbsp; study&nbsp; have shown that Fru&scaron;ka gora is an area characterized by a high&nbsp; diversity&nbsp; of&nbsp; bryophytes&nbsp; and&nbsp; a&nbsp; total&nbsp; number&nbsp; of 235 taxa&nbsp; were recorded (based on literature data and field&nbsp; research).&nbsp; 73&nbsp; taxa&nbsp; were&nbsp; recorded&nbsp; for&nbsp; the&nbsp; first time on this area. Of the total number of taxa, 11% is threatened&nbsp; or&nbsp; under&nbsp; legislative&nbsp; protection.&nbsp; The microcenose&nbsp; method&nbsp; proved&nbsp; to&nbsp; be&nbsp; the&nbsp; most adequate&nbsp; for&nbsp; quantitative&nbsp; sampling&nbsp; of&nbsp; terrestrial bryophytes (with a minimum quadrat size of&nbsp; 0.5x0.5 m in forests and 1x1 m in meadow habitats). For the epiphytic&nbsp; bryophytes,&nbsp; the&nbsp; method&nbsp; of&nbsp; placing&nbsp; the microplots (10x10 cm) on all four sides of the tree at a&nbsp; distance&nbsp; of&nbsp; 20&nbsp; cm&nbsp; is&nbsp; most&nbsp; suitable.&nbsp; The&nbsp; stand structure&nbsp; has a significantly greater influence on the diversity of terrestrial&nbsp; bryophytes&nbsp; in&nbsp; forest&nbsp; habitats compared&nbsp; to&nbsp; soil&nbsp;&nbsp; haracteristics,&nbsp; while&nbsp; in&nbsp; the meadow&nbsp; habitats&nbsp; there&nbsp; is&nbsp; a&nbsp; reverse&nbsp; case.&nbsp; The greatest&nbsp; influence&nbsp; on&nbsp; the&nbsp; diversity&nbsp; of&nbsp; epiphytic bryophytes has height on the tree as well as the type of&nbsp; phorphyte.&nbsp; In&nbsp; the&nbsp; investigated&nbsp; area,&nbsp; nine bryophyte&nbsp; communities&nbsp; were&nbsp; detected&nbsp; in&nbsp; ground bryopyhte&nbsp; flora&nbsp; of&nbsp; forest&nbsp; habitats;&nbsp; six&nbsp; epiphytic communities; five communities in meadow habitats; four&nbsp; communities&nbsp; on&nbsp; rotten&nbsp; trunks&nbsp; and&nbsp; horns;&nbsp; 10 communities&nbsp; on&nbsp; the&nbsp; rocks&nbsp; and&nbsp; stones;&nbsp; four communities&nbsp; in&nbsp; streams.&nbsp; The&nbsp; obtained&nbsp; results represent the&nbsp; base&nbsp; for&nbsp; further&nbsp; bryological&nbsp; research, both floristic and ecological, and the addition&nbsp; to the flora of Serbia.</p>

Unequal sex ratios are widespread in dioecious plants and understanding their cause is important to understanding fundamental aspects of their population dynamics, and yet what causes biased sex ratios in plants is still poorly understood. Competition experiments have been used in plants to predict the outcome of species interactions, but they have rarely been used to help explain sex ratio bias. This study used a response surface competition design to measure the relative competitive abilities of the sexes of the bryophyte Marchantia inflexa (a thallus liverwort of Marchantiaceae) to predict the outcome of competition before the onset of sexual reproductive structures. In bryophytes, dioecy and sex ratio bias is especially common, making them effective organisms for studying sex ratio bias. Given the frequency of female bias in bryophytes, the hypothesis was that females will show a higher competitive ability relative to males. The experiment was conducted in greenhouse conditions at several densities and proportions over the course of seven months. As individuals grew and formed clumps, identities were tracked, and growth measurements were made using photographs and computer imaging software. Both sexes grew on average 41% more with the opposite sex relative to their single-sex cultures. A model predicting future sex ratios showed coexistence between the sexes and predicted a male biased sex ratio of 3.2 males to 1 female. A trade-off was observed for males where single-sex cultures contained more asexual structures than mixed-sex cultures and the reverse for growth rate. Higher levels of asexual reproduction in males in single-sex cultures might be selected for to increase male dispersal for a higher probability of encountering females. This pattern was not found for females. The overyielding results suggest an interaction effect may exist due to niche differentiation between the sexes. In addition, the results suggest that in some dioecious plants a change in sex ratio can occur before differences in their allocation to sexual reproduction.

The microorganisms colonizing plants can have a significant effect on host phenotype, mediating such processes as pathogen resistance, stress tolerance, nutrient acquisition, growth, and reproduction. Research regarding plant-microbe interactions has focused almost exclusively on vascular plants, and we know comparatively little about how bryophytes -- including mosses, liverworts, and hornworts -- are influenced by their microbiomes. Ceratodon purpureus is a dioecious, cosmopolitan moss species that exhibits sex-specific fungal communities, yet we do not know whether these microbes have a differential effect on the growth and physiology of male and female genotypes. Using a common-garden design, we reared ten axenic genotypes of C. purpureus in a controlled environmental chamber. Clonal C. purpureus replicates, with and without the addition of a microbial inoculation, were used to test the effect of a mixed microbial community on vegetative growth, sex expression, photosynthetic efficiency (Fv/Fm and ETR), and chlorophyll content (CFR) for male and female mosses. We found that microbes had a negative impact on the growth and photosynthesis efficiency of C. purpureus, and this effect varied among genotypes of C. purpureus for ETR and growth. Microbes also had a positive, sex-specific effect on chlorophyll content in C. purpureus, with males exhibiting lower CFR values in the absence of microbes. C. purpureus sex expression was marginally negatively affected by microbe addition, but gametangia production was low overall in our experiment. We also conducted preliminary surveys using direct counts from moss ramets to assess the community composition of epiphytic algae associated with our microbe addition and control C. purpureus. These surveys identified three algal morphospecies in association with the microbe addition C. purpureus genotypes, as well as cyanobacteria, nematodes, rotifers, and testate amoeba. No algae, cyanobacteria, or micro-fauna were observed in the control plants. Transplantation of a mixed microbial community from field-to-laboratory conditions may be applied to other bryophyte species under varying environmental conditions to provide insight into how these diminutive yet important ecosystems will respond to environmental perturbation.

Sur les 10500 t d'antibiotiques consommés en Europe chaque année, la moitié sont à usage vétérinaire. Ceux utilisés en pisciculture dulçaquicole sont généralement administrés aux poissons via un aliment distribué directement dans les bassins d'élevage. Leur devenir et leurs effets dans l'environnement aquatique notamment pour l'acide oxolinique (AO), la fluméquine (FLU) et l'oxytétracycline (OTC) suscitent donc un intérêt grandissant. L'objectif de cette thèse est d'étudier le devenir de ces trois antibiotiques dans l'eau, les sédiments et les bryophytes dulçaquicoles. La démarche a été de mettre au point et de valider des méthodes de dosage originales, sensibles, fidèles et précises dans les sédiments et les bryophytes afin de réaliser des études expérimentales finalement validées sur le terrain. Les études de stabilité dans l'eau indiquent que l'AO et la FLU ne sont pas sensibles aux phénomènes d'hydrolyse et de biodégradation et sont peu sensibles à la lumière alors que l'OTC est biodégradable, photosensible et hydrolysable. Une approche intégrant les caractéristiques physico-chimiques sédimentaires met en évidence l'influence de la fraction organique et de la nature minérale de la fraction argileuse des sédiments sur les phénomènes d'adsorption, de désorption et de dégradation de ces antibiotiques. Expérimentalement, Fontinalis antipyretica s'est révélé être un excellent bioaccumulateur des trois antibiotiques. Des études sur l'Elorn (Finistère, France) montrent son intérêt comme espèce sentinelle, notamment pour l'OTC. Des concentrations élevées en FLU, OTC et plus faibles en AO sont relevées à la fois dans les bryophytes et les sédiments. L'utilisation de mousses transférées a prouvé que cette contamination de l'environnement ne provient pas seulement des piscicultures. La stabilité et les concentrations des trois antibiotiques dans l'environnement dulçaquicole posent donc de réelles interrogations quant au risque écotoxicologique qu'ils représentent.

The effect of moderate rates of nitrogen deposition on ground floor vegetation is poorly predicted by uncontrolled surveys or fertilization experiments using high rates of nitrogen (N) addition. We compared the temporal trends of ground floor vegetation in permanent plots with moderate (7–13 kg ha−1 year−1) and lower bulk N deposition (4–6 kg ha−1 year−1) in southern Sweden during 1982–1998. We examined whether trends differed between growth forms (vascular plants and bryophytes) and vegetation types (three types of coniferous forest, deciduous forest, and bog). Trends of site-standardized cover and richness varied among growth forms, vegetation types, and deposition regions. Cover in spruce forests decreased at the same rate with both moderate and low deposition. In pine forests cover decreased faster with moderate deposition and in bogs cover decreased faster with low deposition. Cover of bryophytes in spruce forests increased at the same rate with both moderate and low deposition. In pine forests cover decreased faster with moderate deposition and in bogs and deciduous forests there was a strong non-linear increase with moderate deposition. The trend of number of vascular plants was constant with moderate and decreased with low deposition. We found no trend in the number of bryophyte species. We propose that the decrease of cover and number with low deposition was related to normal ecosystem development (increased shading), suggesting that N deposition maintained or increased the competitiveness of some species in the moderate-deposition region. Deposition had no consistent negative effect on vegetation suggesting that it is less important than normal successional processes.

Rich fens are an important, but threatened, habitat type in the boreal landscape. In this thesis I have examined responses of rich fen vascular plants and bryophytes after drainage and restoration. The effects of drainage on the rich fen flora were observed in a long time study and the responses were rapid and drastic. During an initial stage a rapid loss of brown mosses was observed, followed by increases of sedges and early successional bryophytes, and later by an expansion of dominants. Initial effects of hydrological restoration showed that rewetting can promote re-establishment of an ecologically functional rich fen flora, but has to be combined with other treatments, such as mowing or surface disturbance. After restoration, re-establishment of locally extinct species may be hampered by dispersal limitations. To test if reintroductions could help to overcome dispersal limitations I performed transplantation studies with four common rich fens bryophytes to a rewetted site. The results showed that the species were able to establish, and that survival and growth were promoted by desiccation protection and liming. I further examined competition among three of the most common bryophytes in natural boreal rich fens that usually occur mixed in a mosaic pattern but show small but important microtopographical niche separation. The results indicate similar competitive abilities among the species, and no case of competitative exclusion occurred. The results help to explain the coexistence of these species under natural conditions with microtopographic variation and repeated small scale natural disturbances. Restoring a functional flora in drained rich fens is a complex task, which requires understanding of underlying causes of substrate degradation in combination with suitable restoration measures. The thesis suggests how the results can be used in practical restoration work, and also stresses the need for monitoring of restoration experiments over longer time.

Graduation date: 1995