Effects of different types of management (control, mown, mown + disturbed (gaps) + litter removed) on three moss species of fen meadows were studied. Experimental plots were established at sixteen sites in the Bohemian Forest, in the foothills of the Bohemian Forest and in Českomoravská vrchovina. Relevés and micromaps of bryophytes in the plots 0.5 × 0.5m were sampled at the beginning of the experiment during the summer season of 2010 and then after 3 seasons (during the summer season of 2012) of performing management. The age of the abandoned meadows was also determined and values of pH, conductivity and height of water level of each plot were measured. Positive influences of both types of management on the cover of Tomentypnum nitens and of management with creating gaps and remowing of litter on the cover of Breidleria pratensis were significant. Effect of management on the Sphagnum warnstorfii was significant only when processes of remaining on already occupied places and the expansion to new places were tested separately. Enviromental values did not significantly influence the change of cover of any species between 2010 and 2012. In conclusion, it is clear that diverse management with reasonable use of these practices (mowing, creation of gaps, litter removal) is desirable for maintaining of vital and diverse bryophyte layer.

This study compared three different types of reaches at streams and how bryophyte species richness, diversity and abundance in the riparian zone differ between them. The different types of reaches are those that have been treated by two types of restoration techniques (best practise and advanced) and streams that have still not been restored (channelized). The bryophytes were gathered from 15 tributaries to Vindelälven, which is in northern Sweden. Bryophyte species richness and diversity was highest at the streams that were still not restored, and I found numerous factors that could explain why this was the case. Fourteen environmental variables were tested against the three bryophyte factors to try to explain the variation found in the study. Time since restoration and the amount of tree biomass in the area could explain the species richness found at the different river types. The study shows that short-term effects of restoration on the riparian zone is a decrease in bryophyte species richness and diversity. However, given enough time the bryophytes are expected to recover in regards to species richness and diversity.

Bryophytes form an important component of northern vegetation communities. Mosses efficiently capture aerially deposited nutrients, restricting nutrient availability to the soil. Given that key ecosystem processes of northern ecosystems are nutrient-limited, understanding nutrient cycling of the moss layer is key to understanding ecosystem nutrient and C cycling in these systems. However, the role of the moss layer in regulating ecosystem-scale nutrient and C cycling, while potentially significant, is largely unknown. The aim of this thesis is to investigate the effect of the relative availability of N and P on aspects of bryophyte nutrient uptake, retention and C acquisition. The hypothesis investigated is that the availability of one nutrient will influence the demand for the other and thereby moss nutrient acquisition and retention mechanisms. To test this hypothesis, various aspects of moss nutrient cycling in response to the relative availability of N and P were investigated. As the C cycle is tightly linked to the N and P cycles, the hypothesis extended to include bryophyte C assimilation and decomposition processes of an arctic tundra. Bryophyte nutrient demand was chiefly governed by the tissue N:P ratio. Consequently, nutrient uptake, both from aerially deposited nutrients and through moss-cyanobacteria N2 fixation, and nutrient losses after a simulated rainfall event were mostly in response to the relative availability of N and P rather than the availability of one nutrient alone. This thesis provides novel evidence that ectohydric mosses have the ability to internally translocate nutrients. In conjunction with efficient nutrient capture, this trait makes mosses strong nutrient sinks which are likely to exert considerable control over ecosystem nutrient cycling. The relative availability of N and P played a role in C uptake of mosses. Through the production of recalcitrant litter and their insulating effect on soil microclimate mosses exerted an influence over ecosystem C cycling.

Fatty acid amide hydrolase (FAAH) belongs to a diverse class of enzymes in amidase signature family. In mammals, FAAH is targeted to affect neurological functions because it terminates endocannabinoid signaling by degrading anandamide, a 20C N-acylethanolamine (NAE 20:4). In higher plants, FAAH is known to modulate growth, development and stress tolerance by degrading 12-18C NAEs. Since anandamide was reported to exclusively occur in early land plants, we investigated its metabolic pathway in the moss Physcomitrella patens. Based on the highest identity with ratFAAH, we identified nine orthologs in moss, PpFAAH1 to PpFAAH9. Several bioinformatic tools were used to understand the structural basis of how catalytic residues fold for amidohydrolase activity. Based on these in silicoanalyses of PpFAAHhomologs and their gene expression in response to saturated (NAE16:0) and unsaturated NAE (NAE 20:4) treatment, PpFAAH1was selected for biochemical characterization. Heterologously expressed PpFAAH1 showed highest amidohydrolase activity at 37°C and pH 8.0. Both in vivoand in vitrostudies showed that unsaturated NAE substrate is hydrolyzed faster than the saturated NAE (> 10-fold in vivoand50-fold in vitro). Additionally, transgenic moss lines over expressing FAAH1 showed slower growth and disrupted gametophyte formation when compared to wild type. These data suggest that PpFAAH1-mediated NAE metabolism is likely involved in developmental transition in moss.

Numerical analysis of the lengths and positions of the two basal bodies (BBs), lamellar strip (LS) and anterior mitochondrion (AM) relative to each other in mid‐ and late‐stage spermatids of mosses and liverworts reveals the existence of several well denned, but previously unrecognized, features which clearly distinguish the blepharoplasts of the two groups. The ten possible quotients were calculated from measurements of anterior BB lengths, posterior BB lengths, LS lengths, distances between the anterior tips of the BBs and distances between the transition regions of the BBs in mid‐stage spermatids of 9 mosses and 16 hepatics. These critical data may be quickly compiled from a small number of electron micrographs. A Mann‐Whitney rank order t test showed highly significant differences in 6 of the 10 quotients between the moss and liverwort taxa. The primary data for late‐stage spermatids (4 mosses, 6 liverworts) also included the length of the AM. A Wilcoxon signed rank procedure revealed that the relationship between the AM and other blepharoplast components changed significantly between mid‐ and late‐stage spermatids in mosses but not in liverworts. The clear‐cut numerical differences between the blepharoplast components in each group are related to different patterns of development namely (1) bidirectional assembly of the LS in young spermatids of liverworts versus unidirectional (anterior) elongation at the same stage in mosses (2) elongation of the posterior BB over the nucleus in mid‐stage spermatids of mosses and (3) maturational elongation of the AM in mosses. Since the differences between the blepharoplasts of mosses and liverworts become apparent only during the later stages in ontogeny and since the mode of development of basal body stagger, involving the same precisely defined patterns of proximal triplet microtubule extension, is unique to mosses and liverworts, we suggest that the two groups share a common ancestry. The blepharoplasts of all the taxa used in the calculations are illustrated in a simplified form and the ‘average’ blepharoplast for mid‐ and late‐stage spermatids of both mosses and liverworts is reconstructed from all the data presently available on the two groups. The same analysis of the blepharoplasts of hornworts, birlagellate lycopods, and charophytes highlights the differences between these groups and mosses and liverworts. Most striking is the side‐by‐side orientation of the basal bodies in hornworts and charophytes compared with the staggered arrangement in mosses, liverworts and the lycopods.

Spatial processes have a profound influence on the structure and function of community assemblages. The dispersal of organisms from their place of origin to the location in which they live out their reproductive life is particularly important for plant communities, which generally cannot adjust their location post-germination. Connection between communities at a landscape scale can also influence species persistence, local and regional diversity, and functional turnover at the metacommunity scale. Animals have been shown to disproportionately deposit propagules in particular microsites in many plant species, facilitating the arrival of plants to appropriate niche-space. Birds are particularly notable seed dispersers, given their ability to fly long distances and their behavioral inclination toward using specific microsites within their habitat for foraging and nest building. Despite the known influence of animal behavior on plant dispersal outcomes, little work has been done to investigate the role of animals in dispersing bryophyte (moss, hornwort, liverwort) propagules. In order to examine how birds may affect bryophyte dispersal, I conducted two studies focused on understanding how bird species identity and behavior influence the bryophyte propagules they carry. In addition, I conducted a study to understand how metacommunity structure across a landscape can be influenced by focal spatial scale. In the first study I examined how bird species and foraging behavior impact the topical load of bryophyte spores found on bird surfaces. In order to determine this, I captured passerine birds in mist nets and swabbed them for spores. I found that spores were more abundant on passerine tails than legs, and that overall spore load was higher on larger birds. Thrushes in particular carried more spores than other groups overall. Bark and foliage foraging birds had more spores on their tails than ground foraging birds. From these samples I was able to germinate 242 individual bryophytes, demonstrating that carried spores were readily viable. In the second study, I examined species-specific relationships between bryophytes and the birds carrying them. Swabs from captured birds were grown in the lab and bryophyte species were determined genetically. I used a bipartite network approach to determine the level of specialization of associations within the overall network, as well as how specialized the avian associations of individual bryophyte species were. I then used the phylogenetic distance of bryophytes found on individual bird species in order to assess how specialized the assemblages on a given bird species were compared with a null, random model. I found that bryophyte associations with birds were nonrandom, and that the extent to which those associations were specialized differed by bird foraging behavior. In addition, I found that the diversity of propagules on bird surfaces was significantly nonrandom, with the exception of those bryophytes found on Spotted Towhees. In the final study, I examined the metacommunity structure of bryophytes at both patch and landscape scales across a relict landscape of Valdivian forest in North-Central Chile. This landscape consists of distinct natural patches of forest maintained by coastal fog deposition, surrounding by a dry matrix inhospitable to patch-resident bryophytes. I used quadrats to sample bryophyte species abundance at the base and at breast height of ten trees in each patch, in 20 patches across the landscape. I found that when considering the whole park as one metacommunity, the bryophyte community exhibited a Gleasonian structure, in which individual species turnover was idiosyncratic. Considering assemblages from both heights separately, a Clemenstian pattern was observed, suggesting that within each height compartment, turnover of species tended to happen together. Treating each patch as a metacommunity of individual community trees resulted in a wide variety of metacommunity structures across the park that did not reflect either longitude or latitude. Low canopy cover and small DBH resulted in structures reflecting random species loss. Underlying Shannon diversity did not explain differences in the observed structures. This dissertation provides the first evidence that passerine birds carry bryophyte propagules, and that their individual species use of habitat and foraging behaviors are likely to influence the number and diversity of the bryophytes they are dispersing. This has implications for understanding disjunct species and genetic distributions observed in bryophytes that to date have lacked an explanatory mechanism for long distance directed dispersal. In addition, understanding how avian behavior may disperse propagules at a local to regional scale may provide better insight into the trajectory of bryophyte recruitment on impacted landscapes. I also found that assignation of metacommunity structure is sensitive to spatial scale in bryophytes. Together, these findings increase our understanding of the role that spatial processes play in forming bryophyte communities.

PIKE, L. M., HU, A., RENZAGLIA, K. S. and MUSICH, P. R., 1992. Liverwort genomes display extensive structural variations. Analyses of the total genomic DNA of eight species of liverworts and two species of green algae by thermal denaturation and CsCl buoyant density gradient centrifugation reveal a high degree of structural complexity and interspecific heterogeneity. The hepatic taxa exhibit two or more DNA components of varying base composition. Average G4‐C contents of total cellular DNA calculated from melting profiles are similarly variable, ranging from 38% to 53% G + C. The green alga Chara, a member of the ancestral line to land plants, shows similarities with liverworts in possessing multiple DNA components of comparable complexity, whereas Hydrodiciyon DNA displays a single component. Detailed hybridization analyses of individual density gradient fractions using α‐tubulin, rRNA and ribulose 1,5‐bisphosphate carboxylase/oxygenase large subunit rbcL gene probes were performed to locate the low‐copy number and moderately repetitive nuclear genes, and the chloroplast chromosome, respectively. The location of each gene within the density gradient is highly variable among the organisms examined; a‐tubulin occurs in fractions ranging from 44–64% G + C, rDNA in 50–64% G + C fractions, and the RbcL gene is located in fractions from 30–59% G + C. For a given species, the two nuclear genes normally overlap in their distributions within the gradient. In most instances, neither gene occurs in the major DNA components, indicating that these components may contain repetitive DNAs. The observed variation in the density of the rbcL gene implies substantial reorganization of the chloroplast genome. The overall differences in the genomic components within and between taxa provide insight into the dynamics of DNA structure that have occurred during the extended evolutionary history of these organisms.

Biological screening of extracts of various bryophytes showed that the species Dicranum fulvum gave extracts with activity in both <u>in vitro</u> and <u>in vivo</u> bioassays. This plant was thus selected for extraction and fractionation, monitored by i<u>in vitro</u> bioassays. Isolation was guided by a combination of bioassay and chemical methods, and led to the isolation of three compounds, betulin, 9,l9- cyclolanostâ 23â eneâ 3,25â diol, and B-sitosterol. Purification was achieved by open column, flash column, gel filtration, thin layer chromatography, the chromatotron and crystallization. The isolated compounds were identified by comparisons of spectroscopic data with those of authentic samples and the matching of experimental and literature melting points and optical rotations. / Master of Science

La restauration écologique des tourbières se définit comme l’ensemble des procédés permettant d’assister à la régénération d’une tourbière qui a été dégradée, endommagée ou détruite. La gamme des tourbières perturbées qui nécessitent des actions de restauration est très diversifiée. L’étude de la régénération naturelle des écosystèmes perturbés a fréquemment été utilisée pour développer des méthodes de restauration qui sont adaptées aux types spécifiques de ces écosystèmes. Une compréhension plus complète des trajectoires de régénération, des contraintes environnementales et de dispersion, ainsi que des interactions interspécifiques, est directement reliée au développement de méthodes de restauration et à l’amélioration de nos connaissances sur la réponse des espèces et des communautés à des changements environnementaux. Cette thèse étudie la régénération de la végétation, plus spécialement des bryophytes, ainsi que les facteurs influençant leur régénération dans trois cas problématiques de restauration des tourbières perturbées. Premièrement, la régénération des communautés de bryophytes a été étudiée en fonction des conditions environnementales dans 28 tourbières minérotrophes des Territoires du Nord-Ouest et de l’Alberta ayant brûlé il y a un, deux ou cinq ans. Un changement de dominance a été observé entre les bryophytes pionnières (couvert moyen passant de 16 à 11 %) et les bryophytes de succession tardive (3 à 27 %) entre la 2e et la 5e année après le feu. La répartition et l’abondance des espèces de bryophytes semblent être contrôlées par leurs différences de capacité de régénération en lien avec leur stratégie d’histoire de vie, leur niche écologique et l’effet variable de la biomasse carbonisée. L’intégration de la notion de niche écologique chez les bryophytes de succession tardive ainsi que l’utilisation des espèces ayant un fort potentiel de régénération (comme Aulacomnium palustre et Ptychostomum pseudotriquetrum) devraient être considérées lors de l’élaboration des plans de restauration des tourbières minérotrophes. Deuxièmement, la régénération des sphaignes a été étudiée dans 25 sites donneurs (tourbières ombrotrophes où la végétation de surface a été récoltée pour servir de matériel de réintroduction) sur une chronoséquence de 17 ans en fonction des conditions environnementales et des pratiques de récolte. Les sphaignes dans les sites donneurs se régénèrent en moyenne en 10 ans, quoique des différences mineures dans la composition et l’abondance des espèces ont été observées entre les sites donneurs et les tourbières naturelles. Les espèces pionnières (p. ex., Eriophorum vaginatum), compétitives (p. ex., Sphagnum rubellum) et préférentielles des microhabitats plus humides (p. ex., Chamaedaphne calyculata) étaient plus abondantes dans les sites donneurs. Les pratiques de récolte avaient l’effet le plus important sur la régénération de la végétation, suggérant qu’il est possible d’accélérer la reprise des sphaignes en adoptant des pratiques de récolte appropriées. Des pratiques responsables consistent à éviter les sites donneurs très humides et la récolte durant le milieu de l’été lorsque les mousses ont un plus faible potentiel de régénération et lorsque le risque d’enlisement de la machinerie est élevé. Troisièmement, la régénération et le développement de tapis de sphaignes ont été étudiés dans deux types de tourbières restaurées et colonisées par des plantes pionnières de type graminoïde (Cypéracées). Dans le premier cas, le Carex aquatilis dominait un fen modérément riche restauré et formait des communautés denses avec beaucoup de litière. Dans le deuxième cas, l’Eriophorum angustifolium était dominant avec un faible couvert de litière dans une tourbière à sphaignes restaurée où la densité de la plante graminoïde avait été contrôlée par coupe répétée. Il a été démontré que l’effet des plantes graminoïdes sur les tapis de sphaignes était déterminé par leur litière plutôt que par la structure de la plante elle-même. En raison de l’ombre créée par la litière compacte, la présence d’une communauté dense d’une plante graminoïde accumulant beaucoup de litière comme Carex aquatilis ne semble pas être bénéfique pour développer des tapis de sphaignes productifs. La décision de contrôler les plantes graminoïdes pour accroitre le développement des tapis de sphaignes devrait prendre en considération, bien sûr, le couvert de la plante (non requis si le couvert moyen < 30 %), mais aussi sa forme de croissance (moins essentiel lorsque la plante pousse en tige unique), de même que ses potentiels d’accumulation de litière et d’envahissement (p. ex., Phragmites australis, Scirpus cyperinus). En somme, en plus de répondre spécifiquement à trois cas problématiques de restauration de tourbières perturbées, cette thèse fournit une compréhension améliorée des processus de régénération naturelle des écosystèmes de tourbières et des facteurs qui les influencent. Les résultats ont un lien direct avec le développement d’outils pour la restauration et avec l’approfondissement de nos connaissances sur les réponses des organismes et des communautés végétales aux changements de l’environnement. / The ecological restoration of peatland is defined as all the processes permitting the regeneration of a peatland that has been degraded, damaged or destroyed. The landscape settings and types of peatlands that require restoration actions is very diverse. The study of natural regeneration of disturbed ecosystems has frequently been used to develop restoration methods that are adapted to specific types of ecosystems. A comprehensive assessment of regeneration trajectories and the environmental and dispersal constraints, as well as the interspecific interactions is directly related to the development of restoration methods and the improvement of our knowledge on the response of species and communities to environmental changes. This thesis studies the regeneration of vegetation, especially of bryophytes, and the factors influencing their regeneration in three problematic cases of restoring disturbed peatland. Firstly, the regeneration of bryophyte communities was studied against a range of environmental conditions in 28 minerotrophic peatlands in the Northwest Territories and Alberta that had burned one, two or five years ago. A shift of dominance between pioneer (mean cover from 16 to 11 %) and late successional bryophytes (from 3 to 27 %) was observed between the second and fifth year after the fire. Bryophyte distribution and abundance were controlled by the species difference in terms of regeneration capacity related to their life history strategy, habitat niche, and the variable effect of the burned biomass. The integration of the ecological niche concept for late successional bryophytes and the use of species with a high potential of regeneration (such as Aulacomnium palustre and Ptychostomum pseudotriquetrum) should be considered during the elaboration of restoration plans of minerotrophic peatlands. Secondly, the regeneration of Sphagnum mosses was studied in 25 donor sites (peatlands where surface vegetation was harvested to supply reintroduction material) on a chronosequence of 17 years according to environmental conditions and harvesting practices. It takes on average 10 years for Sphagnum mosses in donor sites to recover, though minor differences in the species composition and abundance was observed between donor sites and natural peatlands. Pioneer species (e.g., Eriophorum vaginatum), competitive species (e.g., Sphagnum rubellum) and preferential species of wet microhabitats (e.g., Chamaedaphne calyculata) were more abundant in donor sites. Harvesting practices had the greatest effect on the regeneration of donor sites, suggesting that it is possible to speed up Sphagnum regeneration by choosing appropriate management practices. Best practices would be avoiding very wet donor sites and harvesting in the midsummer should be avoided when mosses are at their lowest regeneration potential and when the risk of machinery sinking is high. Thirdly, the regeneration and development of the Sphagnum carpets were studied in two experiments conducted in two types of restored peatlands colonized by pioneer graminoid plants (Cyperaceae). In the first experiment, Carex aquatilis dominated a moderately rich restored fen and formed dense communities with a lot of litter. In the second experiment, Eriophorum angustifolium was dominant with a low cover of litter in a restored cutover Sphagnum-dominated bog where the graminoid plant cover was controlled by repeated mowing. It was demonstrated that the effect of graminoid plants on the Sphagnum carpet was determined by the litter rather than by the structure of the plant itself. Because of the shade created by the dense litter, the presence of a community of a graminoid plant that accumulates a lot of litter such as Carex aquatilis is not beneficial for the formation of productive Sphagnum carpets. The decision to control graminoid plants to enhance the growth of Sphagnum carpets should consider the cover of the plant (not necessary when mean cover < 30 %), but also its life form (less necessary when the plant grows in unique stem), its litter accumulation and potential for invasion (e.g. Phragmatis australis, Scirpus cyperinus). In conclusion, this thesis, in addition to specifically address these three problematic cases, provides a more comprehensive assessment of the processes of natural regeneration of peatland ecosystems and of driving factors. The results have a direct link with the development of tools for the restoration of peatlands and with a deeper understanding of the responses of plants and communities to environmental changes.

L’étude phytochimique des hépatiques de la Nouvelle-Calédonie a été réalisée sur 34 espèces d’hépatique (dont 14 endémiques) appartenant à six familles (Plagiochilaceae, Lophocoleaceae, Lepidoziaceae, Porellaceae, Lejeuneaceae et Frullaniaceae). La composition chimique, notamment en constituants volatils principalement sesquiterpéniques, de ces espèces a pu être établie pour la première fois pour la majorité des espèces étudiées, et il s’agit de la première étude phytochimique réalisée sur les genres Chiastocaulon et Acromastigum. Environ 260 constituants ont pu être déterminés pour ces espèces ci-étudiées, ils appartiennent en majorité à la famille des terpénoïdes, et à d’autres familles de métabolites secondaires d’intérêt tels que les composés aromatiques. Quatre nouveaux produits naturels ont pu être isolés et caractérisés.L’activité antibactérienne d’extraits d’espèces issues de trois familles (Plagiochilaceae, Lepidoziaceae, Lejeunaceae) a été montrée sur deux souches bactériennes (Staphylococcus aureus, Staphylococcus epidermidis). Les extraits à l’éther les plus actifs sont ceux de Bazzania parisii (actif sur S. epidermidis avec une CI50 de 19,3±0,8 μg/ml) et de Bazzania subintegra (actif sur S. aureus avec une CI50 de 16,3±1,1 μg/ml). Les extraits méthanoliques les plus actifs sont ceux : de Bazzania serrifolia (actif sur S. aureus avec une CI50 de 17,7±1,9 μg / ml), de Chiastocaulon caledonicum (actif sur S. aureus avec une CI50 de 6,7±1 μg/ml), de Bazzania sp. AD212 (actif sur S. epidermis avec une CI50 de 14,1±1 μg/ml) et de Bazzania francana (actif sur S. epidermis avec une CI50 de 17,0±1,6 μg/ml). / Phytochemical survey of 34 New-Caledonian liverwort species (including 14 endemic species) belonging to six families (Plagiochilaceae, Lophocoleaceae, Lepidoziaceae, Porellaceae, Lejeuneaceae, and Frullaniaceae) had been performed. Chemical composition of these species, mostly of volatile constituents, had been established for the first time for most of them and phytochemical study of species from Chiastocaulon of Acromastigum genus had been performed for the first time. Nearly 260 compounds were reported as identified constituents of these plants extracts, most of them being terpene. Four new natural products had been characterized.Antibacterial activity of liverworts extracts from three Hepaticeae families (Plagiochilaceae, Lepidoziaceae, and Lejeuneaceae) had been shown on two strains (Staphylococcus aureus, Staphylococcus epidermidis). The most active ether extracts were found to be those from Bazzania parisii (active on S. epidermidis having an IC50 of 19.3±0.8 μg/ml) and from Bazzania subintegra (active on S. aureus having an IC50 of 16.3±1.1 μg/ml). The most active methanolic extracts were found to be respectively from : Bazzania serrifolia (active on S. aureus having an IC50 of 17.7±1.9 μg / ml), Chiastocaulon caledonicum (active on S. aureus having an IC50 of 6,7±1 μg/ml), Bazzania sp. AD212 (active on S. epidermis having an IC50 of 14.1±1 μg/ml) and Bazzania francana (active on S. epidermis having an IC50 of 17.0±1.6 μg/ml).