RARE PLANTS

Cazaux-Sanguinet Lake until recently kept exceptional oligotrophic favouring the development of rare plants. In a particularly poor nutrient environment, species have developed specific survival strategies favouring a high biodiversity. A large number of these rare plants at the edge of the Lake protection at national, European or global level.
In 2005, surveys of some rare plants was made at the initiative of the SAN to the Natura2000 classification. Download these detailed, inventories certified by doctor Jean Laporte-raw, by clicking on the following link: FloreAttestation
Here are some of the rare plants of the edges of the Landes Lakes and, in particular, the Lake of Cazaux-Sanguinet.

Hover over a document for more details.

The Quillwort of Bory, plant endemic to the South West

An aquatic plant that is sensitive to pollution

The Quillwort of Bory (Quillworts boryana) is a small herbaceous plant, smooth and hairless. Its leaves are semicircular section, filiform, distributed in clumps of erect or discarded and a fairly straightforward green color. They are persistent, are renewed in the spring or early summer and measure between 5 and 15 cm in length.
Individuals gathered in colonies, which can be more or less dense and can reach some tens of square meters. The number of plants varies strongly from one colony to another.

The Bory Quillwort is aquatic, but can live temporarily out of the water, where the substrate remains damp. She is present at the edge of the acidic ponds at bottom flat and sandy and grows at a relatively low depth (10-50 cm). Highly sensitive to organic pollution of the environment, it only found in calm, pure and crystal clear waters.
It colonizes sands barefoot and poor in humus. The appearance and the accumulation of organic debris on the sand may lead to its disappearance and its replacement by more appropriate aquatic vegetation (water lilies and pondweeds including).

Water oligotrophic very little mineralized Plains sandy, characteristics of the Lake Cazaux and Sanguinet, meet the requirements of the Bory Quillwort and are one of the last places of presence of the plant. Indeed, the species is endemic to the South-West of the France. Although having been reported in different regions of Spain, several authors have questioned these data. These uncertainties seem linked to difficulties in taxonomic order, including variants of the species or subspecies level.
This extremely limited range, as well as threats related to human activities, make the very vulnerable Bory Quillwort. If it is not preserved, the Bory Quillwort is doomed to disappear.

An endangered plant that must be protected

Status of the species:

• “Flora-fauna-Habitat” directive: annexes II and IV
• Berne convention: Annex I
• Species protected at national level by France (annex I)
• Rating IUCN: World: vulnerable; France: vulnerable

Excerpt from the National inventory of natural, directed by the National Museum of natural history heritage:

‘[…] given the limited number of stations and its restricted range, this species deserves careful monitoring and responsibility for the France a strong commitment to its preservation. »

As indicated by the status of the species, the Bory Quillwort is a protected plant. Yet no action is currently for the species and stations where its presence has been confirmed are integrated in any protected area. In current stations, it would seem that of Bory Quillwort populations, although only very localized, are relatively stable. Nevertheless, since the beginning of the century, the disappearance of several stations (Souston, bed-and-mix, Aureilhan and Leon) caused a regression of the Bory Quillwort.

The main threats to the extirpation of the species are:

• siltation resulting from eutrophication of waters;
• trampling;
• sports.

By observing the last inventories in particular, it seems that sites subject to trampling experienced the strongest decline in workforce.
Conversely, it is interesting to note that this case would seem able to colonize new areas when they are cleaned. It comes, for example, lakes of hunting to “tonne” (huts of the waterfowl hunting).
The main proposals for the preservation of the Bory Quillwort are therefore:

• maintain the character oligotrophic waters avoiding priority inputs of phosphorus (element limiting);
• maintain natural; hydraulic Dynamics
• do not use herbicides;
• limit traffic to the concerned sites.

A plant to fight the greenhouse effect

According to the studies of the IRSTEA (national Institute for research on Science and technology for the environment and agriculture), it would seem that the Bory Quillwort facilitates uptake of carbon in the soil, thus limiting the production of gas greenhouse.

An excerpt from the site of the IRSTEA:

For this study researchers were particularly interested in lawns formed by the isoetides aquatic heritage small sized plants that colonize Sandy substrates, among which we can find:
-lobelia lobelia, (whose Aquitaine Lakes represent the southern limit of their distribution in Europe)
-the Littorelle to a
flower – and the Quillwort of Bory (endemic, that is, its global distribution is restricted to the Aquitaine Lakes).
“We were able to demonstrate the key role played by these species in the regulation of gas emissions greenhouse”, explains Cristina Ribaudo, engineer of research at the centre Irstea of Bordeaux. A first! “So far, we know these plants from the botanical point of view (distribution, presence, etc.) and ecophysiological perspective (i.e. responses behavioural and physiological to their environment agencies), but no studies had been conducted at the community level;” still less compared to their interaction with the cycle of carbon and methane.”

One more reason to monitor and protect this unique species !