Search results for "Ditch"
showing 10 items of 16 documents
The effects of drainage and restoration of pine mires on habitat structure, vegetation and ants
2016
Habitat loss and degradation are the main threats to biodiversity worldwide. For example, nearly 80% of peatlands in southern Finland have been drained. There is thus a need to safeguard the remaining pristine mires and to restore degraded ones. Ants play a pivotal role in many ecosystems and like many keystone plant species, shape ecosystem conditions for other biota. The effects of mire restoration and subsequent vegetation succession on ants, however, are poorly understood. We inventoried tree stands, vegetation, water-table level, and ants (with pitfall traps) in nine mires in southern Finland to explore differences in habitats, vegetation and ant assemblages among pristine, drained (30…
Substantial decline of Northern European peatland bird populations: Consequences of drainage
2017
Northern European peatlands are important habitats for biological conservation because they support rich biodiversity and unique species compositions. However, historical management of peatland habitats has had negative consequences for biodiversity and their degradation remains a major conservation concern. Despite increasing awareness of the conservation value of peatlands, the statuses and ecological requirements of peat land species have remained largely understudied. Here, we first analysed temporal trends of Northern European peatland birds to document the status of their populations using bird data from five different countries. Second, we used Finnish monitoring data to assess habit…
The neolithic settlement of Limoneros (Elche, Alicante)
2020
[EN] This paper shows the results of rescue archaeology campaigns undertaken on the site of Limoneros, an open-air settlement located to the south of Elche (Alicante), in the alluvial plain of the Vinalopó river and dated on the first half of the 5th millennium cal BC. The settlement entails different negative structures, including two stretches of ditch, silos and basins, structures finally reused as a waste area. The analysis of the recovered evidences allows the characterization of the activities developed by a farming community in a territory articulated by the river Vinalopó, where other settlements dated back to the same period have been documented. Therefore, Limoneros supplies relev…
La motte médiévale de Drosnay (Marne) : résultats de deux sondages archéologiques
2011
Deux opérations de diagnostic réalisées en 2008 et 2009 ont permis de mettre au jour un segment du fossé d’enceinte d’une motte répertoriée depuis le XIXe s., ainsi que les restes d’un bâtiment en pierre sur sa partie sommitale. Le fossé a livré un mobilier dont la chronologie est centrée sur le XIIIe s. alors que le bâtiment n’est pas antérieur au XVe s. Les remaniements ayant affecté ce site sont nombreux. Dès le XVe s. d’importants travaux de remblaiement et de nivellement semblent modifier l’angle sud-ouest de la motte. Cependant, ce sont les terrassements contemporains qui ont irrémédiablement détruit la plus grande part des vestiges. Seule la basse-cour peut désormais conserver des ve…
The effects of long-term drainage and subsequent restoration on water table level and pore water chemistry in boreal peatlands
2014
Summary Degradation by drainage threatens biodiversity and globally important peatland ecosystem functions such as long-term carbon sequestration in peat. Restoration aims at safeguarding peatland values by recovering natural hydrology. Long-term effects of drainage and subsequent restoration, especially related to within-site variation of water table level and pore water chemistry, are poorly known. We studied hydrological variation at 38 boreal Sphagnum peatland sites (pristine, drained and restored) in Finland. The average water table level was significantly lower at Drained than Pristine sites especially near the ditches. We also observed large pore water chemical differences between Dr…
Effect of catchment characteristics on aquatic carbon export from a boreal catchment and its importance in regional carbon cycling
2013
Inland waters transport and emit into the atmosphere large amounts of carbon (C), which originates from terrestrial ecosystems. The effect of land cover and land-use practises on C export from terrestrial ecosystems to inland waters is not fully understood, especially in heterogeneous landscapes under human influence. We sampled for dissolved C species in five tributaries with well-determined subcatchments (total size 174.5 km(2)), as well as in various points of two of the subcatchments draining to a boreal lake in southern Finland over a full year. Our aim was to find out how land cover and land-use affect C export from the catchments, as well as CH4 and CO2 concentrations of the streams,…
Stable carbon isotopic composition of peat columns, subsoil and vegetation on natural and forestry-drained boreal peatlands.
2018
We studied natural and forestry-drained peatlands to examine the effect of over 34 years lowered water table on the δ13C values of vegetation, bulk peat and subsoil. In the seven studied sites, δ13C in the basal peat layer was 1.1 and 1.2 ‰ lower than that of the middle-layer and surface layer, respectively. Furthermore, there was a positive correlation between the δ13C values of the basal and surface peat layers, possibly due to carbon (C) recycling within the peat column. In the same mire complex, natural fen peat δ13C values were lower than those of the nearby bog, possibly due to the dominance of vascular plants on fen and the generally larger share of recycled C in the fens than in the…
On Holditch's theorem and related kinematics
2019
El teorema de Holditch es un resultado clásico sobre áreas de curvas planas generadas por el movimiento de segmentos. Esta construcción está estrechamente relacionada con otros tipos de curvas como, por ejemplo, curvas paralelas, curvas de anchura constante o curvas de bicicletas. Se compilan las propiedades básicas de este tipo de curvas y se da una revisión histórica sobre el teorema de Holditch y teoremas relacionados de cinemática. Primero, la situación plana de Holditch se define rigurosamente y se consideran ciertos problemas como la existencia de dicha construcción o el modo de evitar movimientos retrógrados en el segmento que se va moviendo. En el enunciado del teorema de Holditch a…
Le sanctuaire laténien de Semoine, « Voie Palon » (Aube)
2012
A rescue excavation in 2003 resulted in the discovery of a building on piles, constructed between two sections of ditch, of which the one on the north side has an entrance. The chronological data of the building and two ditches match and demonstrate the existence of cults during La Tène C2. Evidence of the cults is given by a small quantity of deliberately mutilated weapons, as has been found in other La Tène sanctuaries. Dating the creation of the enclosure is problematicaln but it probably derives from La Tène C1. Although sections of the site remained unexcavated, the stratigraphy of the ditches reveals the brevity and limited and unusual nature of the practices. This study links them to…
Fontaines (Saône-et-Loire). Place de l’Église [notice archéologique]
2019
Le village actuel de Fontaines, situé à environ 8 km au N.-O. de Chalon-sur-Saône, se développe sur 1,5 km de long selon un unique axe E-O, depuis la montagne Saint-Hilaire à l’ouest, occupée au Néolithique puis durant l’Antiquité tardive et le haut Moyen Âge, jusqu’à l’église paroissiale Saint-Just, à l’est. Malgré une emprise limitée et contrainte par de nombreux réseaux existants, l’opération a permis de documenter l’environnement immédiat de l’église, occupé depuis l’Antiquité jusqu’à nos jours.