The castle on the river side
The castle is built on the bank of one of the numerous meanders of the River Oise. In this area, swamps as well as the river provided, even before the 11th century, the main means of defense while the close-by forest offered vast hunting grounds.
Presently the swamps have disappeared, the forest has moved back a few kilometers, but the environment, fauna and flora equally, remains remarkable. The castle is set within a vast wet area bordering a site that’s been classified as a Special Protection Area, the object of a safeguard and protection plan at the regional and European levels (Natura 2000).
Numerous birds live there, either during their migrations or permanently; storks, kingfishers, grey herons can be observed as well as protected species as certain rare varieties of bats and the small copper butterfly. The flora is exceptionally rich: more than 400 species of wild plants have been recorded in the immediate vicinity of the castle. Natural vegetation – ashes, alders, willows – is vigorous and new growths of elms can be found of which complete extinction was feared after the cryptogamic attack around 1975.
- Treasure valley: the alluvial plain of the Oise River
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The plain of the Oise River during the floods
During his canoe journey down the Oise River, Robert Louis Stevenson was amazed by this vast bucolic plain that he compared to a fenceless Pampa.
This was in 1876… Even though it has now been developed and shaped by humans it is still relatively preserved, a rarity in Europe.
- A water-structured system
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The Oise River springs up around Chimay in Belgium to reach the Seine River in Conflans Ste Honorine at the end of a 300km journey along which it flows right through Picardie. The River itself is actually only the visible part of a real “liquid iceberg”. Rain waters gather and drain through a huge 1 600 000 hectare basin covering two thirds of the Picardie region.
The main stream, the underground reservoirs, the tributaries, the alluvial fields, all the elements of the flowing basin are initially connected. Both the moving of sediments and the exchanges of nutriment are maximized by the multiplicity of water flows. All parts are intricately interconnected. Even though the river only flows down from 180m in Hirson to 100m in Guise, it reaches only 37m in Quierzy the main drop being in La Fère which marks the beginning of the mid-valley of the river
- Floods: the breath of the river
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With the heavy winter rains, the river turns into a vast flood plain. From the minor riverbed it spreads into the main one. Both the flooding and the withdrawal of waters are quick. The plain plays a major role in the regulation of floods. Spreading through the fields around Quierzy the flood slows down and sheds its power. Composed mainly of sands both the ground and the underground sponge up and filter the water. Set in the alluvium that constitute the main bed a first alluvial sheet lays parallel to the surface bed. Somewhat deeper another larger sheet transits through chalk. At the beginning of winter, these different levels gorge themselves with water, absorbing part of both rain falls and floods thus purifying the water.
On top of its hydraulic importance the main bed of the mid-valley of the river hosts much wildlife. During flooding, ducks and geese and swans as well as gulls invade the valley. Whether migrating or sedentary they benefit from the abundant food supplier that is the flooded valley.
- Fauna and flora of the mid-valley: a fabulous heritage
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The mid-valley is one of the largest zones of reproduction.
In the spring rich vegetation thrives on the wet ground. Bacteria and plants benefit from minerals accumulated in the alluvium. A multitude of birds, plants, insects as well as amphibians make this ecological area comparable to the Marquenterre the well know natural preserve of Picardie. Warm evenings are enchanted by green rennet’s concerts; in the daytime, they leave the water and retire in the vegetation bordering the pond or floating on it. In April, crested tritons leave their wintering shelters and take to the water to reproduce. The mid-valley is also one of the rare areas where the summer-teal nests: a few couples install their nests at the edge of the pond or an inert tributary where they are well hidden by luscious vegetation. Kingfishers and shore swallows dig horizontal galleries in the banks of the river to deposit their eggs.
Classified as a second fishing category the river mainly hosts cyprinids that thrive in silt and sludge river bottoms. Among other fish, the scaleless Planer’s lamprey stops eating when adult. River monkfish and pike find it a rare refuge in Picardie. Pike use floods to fray in fields and other inert tributaries and, like many other species, benefits from the irregularities in the flow of waters. Its reproduction cycle has been developed according to the periodicity of floods. Damsels are born in ponds and hunt insect that venture over the waters.
In Summer the level of the River drops. At its lowest level, the Oise river is then fed from the alluvial reserves.
The ever present water is part and parcel of the biological importance of the valley.
The grey heron
Château de Quiersy
Charles Martel choisit d'y finir ses jours, en 741.
Il a préparé l'avènement de son fils Pépin le Bref, dont l'épouse, Bertrade de Laon - plus connue sous le nom de Berthe aux grands pieds, va mettre au monde l'année suivante à Quierzy le futur Charlemagne.
Pépin le Bref reçoit à Quierzy en 754 le pape Etienne II et signe avec lui la donation de l'exarchat de Ravenne, reconnaissant aux papes un pouvoir temporel qui perdurera mille ans. Quelques jours plus tard, Etienne II sacre Pépin roi des Francs à Saint Denis.
Son successeur Charlemagne transforme progressivement la villa en palais et c'est sur ses fondations que s'élève le château actuel. Sacré empereur d'Occident par le pape Léon III à Rome en 800, il invite le pape à Quierzy en 804 et renforce les liens entre la Papauté et la France.
Son petit-fils, Charles le Chauve, écrit à Quierzy une nouvelle page de l'Histoire, en y signant le capitulaire de 877 qui établit l'hérédité des offices de la noblesse : il restera en vigueur jusqu'à la Révolution française, neuf siècles plus tard.
