The best way of dealing with the restoration of chalk grassland encroached by scrub is unclear and the subject of many debates. The traditional method is to clear the scrub primarily by manual methods of cutting the scrub and after clearance the land is left to regenerate naturally. More recently the development of using livestock to browse and gradually reduce the scrub is thought to be an alternative. However the effectiveness of either of these methods (Manual clearance or Livestock browsing) is questioned by many and some believe that once scrub has encroached, the soils beneath this will become too enriched to be able to support a chalk grassland flora. This thesis aimed to provide a better understanding by undertaking a five year investigative trial of the two restoration methods and comparing and examining the ability of these to successfully restore a chalk grassland habitat. To undertake this both methods were trailed on scrub invaded chalk grassland and changes in vascular plants and invertebrates were monitored throughout trial period. Areas of nonintervention scrub were also included to act as controls. Successful restoration was assessed by comparing the results from the trials with measurable vascular plant restoration targets that were identified and set from known chalk grasslands in favourable condition. Soil fertility within the trial area was also examined to determine if the soils were considered to fertile to support a chalk grassland flora and costs and practicalities of using ether method were recorded throughout enabling these to be taken into account. The results showed that differences in both the species richness and composition of vascular plants and spider and beetles invertebrate species occurred. Soil fertility was found to suitable to support chalk grassland plants and vascular plants species were identified as moving away from those associated with scrub into those associated with chalk grasslands. It was observed however that on the areas trailed using Manual clearance, an initial flush of ruderal species occurred after clearance, it was therefore concluded that for Manual clearance to be successful continued restoration management is required if these species are to be controlled. It was also observed that the areas trailed using Manual clearance were moving towards successful restoration quicker those trailed using Livestock browsing thus indicating that the rate of change is more gradual using Livestock browsing. This rate of change was also found to occur within the invertebrate beetles and spider communities. Species richness within the spider communities however decreased on the areas manually cleared. Costs of using the restoration methods showed that the use of Livestock browsing was five times more costly that using Manual clearance. However it was found that majority of Livestock browsing costs incurred through welfare and husbandry of the stock. Restoration using Manual clearance also involved using livestock once scrub had been cleared however the costs of these were born by a local grazier and thus did not show as a cost of restoration. It was concluded that if a grazier is not found then these costs would be incurred. Overall it is concluded that both Livestock browsing and Manual clearance have the ability to successfully restore a chalk grassland community but that this must be viewed as a long term objective. Restoration management is critical to continue after clearance until restoration targets have been met.

Master of Fine Arts thesis by Alexandra Thiesson

This study had for its aim the collection, identification, and listing of the spermatophytes growing upon the Austin Chalk formation of Collin County, Texas.

L’aquifère de la craie est un milieu hétérogène complexe lié à une large gamme de porosités (matrice, fractures et conduits karstiques), entrainant une forte hétérogénéité des processus et des vitesses de transfert (de 10-8 m s-1 à plusieurs mètres par jour). De plus, l’aquifère de la craie est recouvert par des formations superficielles (argiles à silex, lœss et dépôts argilo-sableux) d’épaisseurs variables, dont l’influence sur les écoulements au sein de la ZNS est encore mal connue. Le but de cette thèse est d’étudier le fonctionnement hydrodynamique et géochimique des eaux souterraines libres de la craie, et en particulier le rôle de la ZNS et des formations superficielles. L’approche suivie a consisté à étudier la variabilité spatio-temporelle du niveau d’eau de la nappe, des débits de percolation et de la géochimie des eaux souterraines et à rechercher les facteurs de contrôle de cette variabilité en la croisant aux caractéristiques de la ZNS de la craie, des formations superficielles, de l’occupation des sols et du climat. Cette approche a été mise en place à deux échelles spatiales : à une échelle régionale au Nord-Ouest du Bassin de Paris, autour de l’anticlinal de Bray et à une échelle locale sur le site de la carrière souterraine de Saint-Martin-le-Nœud (site particulièrement intéressant de moins d’un km2, donnant accès aux eaux de la nappe et aux eaux provenant de la ZNS). Les chroniques de pluie efficace, de débit de percolation et de variation du niveau d’eau ont été analysées grâce à des méthodes de traitement du signal. La géochimie des eaux a été étudiée statistiquement et par l’utilisation de traceurs naturels (ions majeurs, conductivité électrique) ou anthropiques (pesticides). A Saint-Martin-le-Nœud, l’épaisseur et la nature de la ZNS et des formations superficielles ont été étudiées grâce à des méthodes géophysiques et par le creusement de trois fosses en surfaces de la cavité. Les résultats ont montrés pour les deux échelles spatiales (1) Une variabilité temporelle relativement faible : la réponse de la nappe et l’arrivée des eaux de percolation après une période de recharge sont lentes et tamponnées ; A l’échelle régionale, les variations temporelles de la géochimie sont faibles. A l’échelle locale, l’évolution de la conductivité électrique des eaux des lacs montre des variations temporelles de la minéralisation des eaux relativement lentes. Cependant, les concentrations en NO3-, Cl- et SO42- des eaux des lacs varient significativement. (2) Une variabilité spatiale très marquée : à l’échelle régionale, les variations piézométriques sont très différentes d’un forage à l’autre. De même, dans la cavité de Saint-Martin-le-Nœud, les variations du niveau des lacs et les flux de percolation diffèrent spatialement ; La géochimie des eaux présente également une forte hétérogénéité spatiale, que ce soit à l’échelle régionale ou locale. / The Chalk aquifer is a complex and heterogeneous system associated with a wide range of porosity (matrix, fractures and karstic conduits). These characteristics lead to a high heterogeneity of transfer processes and speed (ranging between 10-8 m s-1 and several metres per day). Furthermore, the Chalk aquifer is overlaid by superficial layers (clay-with-flints, loess and clayey-sandy deposits) with varying thicknesses. The impact of these formations on groundwater flows in the unsaturated zone (UZ) is still poorly understood. The aim of this thesis was to study the hydrodynamics and geochemical characteristics of free Chalk groundwater and particularly the role of the UZ and superficial layers. The chosen approach consisted in studying the spatial and temporal variability of groundwater level, dripping water discharges and groundwater geochemistry and search for controlling factors of this variability and compare it to the characteristics of the UZ of Chalk, the superficial layers, the land use and the climate. This approach was implemented at two spatial scales: at the regional scale of the North-West of the Paris Basin, around the Bray anticlinal and at the local scale of the underground quarry of Saint-Martin-le-Nœud which is a particularly interesting site (area below 1 km2) giving access to both the water table and the UZ water. Effective rainfall (Peff), dripping water discharge and water level variation chronicles were analysed using signal processing methods. Groundwater geochemistry has been studied statistically and using natural (major ions, electric conductivity) and anthropic (pesticides) tracers. At Saint-Martin-le-Nœud, the nature and thickness of the UZ and the superficial layers have been investigated with a geophysical survey and three holes were dug in the fields above the quarry. The results showed at both spatial scales a relatively low temporal variability with low and smooth water table responses and long time between reload periods and dripping water arrival. At the regional scale, the temporal variations of groundwater geochemistry are low. At the local scale, the evolution of underground lakes water electric conductivity indicates that water mineralization displays relatively low temporal variations. However, NO3-, Cl- and SO42- concentrations in lakes water varied significantly during the study. The results also highlighted a strong spatial variability. Thus, at the regional scale, piezometric variations are very different from one borehole to the next. Similarly, in the quarry of Saint-Martin-le-Nœud, lakes water level and dripping water discharges are spatially heterogeneous. Water geochemistry also displays a strong spatial variability at both regional and local scales.

The Chalk Line (June 1930), the first of two yearbooks published in 1930 by the students of East Tennessee State University, known then as East Tennessee State Teachers College. / https://dc.etsu.edu/yearbooks/1011/thumbnail.jpg

The Chalk Line (1935), a yearbook published by the students of East Tennessee State University, known then as East Tennessee State Teachers College. / https://dc.etsu.edu/yearbooks/1017/thumbnail.jpg

The Chalk Line (August 1930), the second of two yearbooks published in 1930 by the students of East Tennessee State University, known then as East Tennessee State Teachers College. / https://dc.etsu.edu/yearbooks/1012/thumbnail.jpg

The Chalk Line (1931), a yearbook published by the students of East Tennessee State University, known then as East Tennessee State Teachers College. / https://dc.etsu.edu/yearbooks/1013/thumbnail.jpg

The Chalk Line (1932), a yearbook published by the students of East Tennessee State University, known then as East Tennessee State Teachers College. / https://dc.etsu.edu/yearbooks/1014/thumbnail.jpg

The Chalk Line (1933), a yearbook published by the students of East Tennessee State University, known then as East Tennessee State Teachers College. / https://dc.etsu.edu/yearbooks/1015/thumbnail.jpg