Aquatic plant proliferations in France: biological and ecological features of the main species and favourable environments: 1 Synthesis of a bibliographic survey | Les proliférations végétales aquatiques en France : caractères biologiques et écologiques des principales espèces et milieux propices : 1 Bilan d'une synthèse bibliographique

[Departement_IRSTEA]GMA [TR1_IRSTEA]12 - MILEAU / ALTERMIL

National audience

Английский. Management of water-bodies affected by prolific growths of plants pose several problems related to assessment of created imbalances. The intensity of these phenomena should be considered on both spatial and temporal scales, as well as the impact of negative effects on practical uses of the water-bodies by man. An examination of invading growths recorded on the French hydrographic system has been carried out. As a result, an inventory of the most relevant plants was produced, called "risk species" belonging to different macrophyte groups like macro-algae, native hydrophyte phanerogams as Ranunculus sp., Potamogeton sp., Myriophyllum sp., Ceratophyllum sp., Lemna sp., and introduced phanerogams like Elodea sp., Lagarosiphon sp., Ludwigia sp., Myriophyllum aquaticum. Some helophyte plants, Cyanobacteria and two riparian introduced species (Fallopia japonica and Impatiens glandulifera), have also been considered. Biological strategies determine their proliferation potential by developing high growth and substantial propagation abilities, through some special morphological and physiological features and means of reproduction. Environment types and factors favour this capacity. These favourable environments are connected with environmental conditions such as high irradiation, mostly linked to shallow depth and water warming, stable or low hydrological conditions, high mineralization and trophic level. The occurrence of dense vegetation is usually the combination of these two aspects, with the influence of mostly several favourable factors. Some situations of minimal and maximal risks can be defined. This knowledge should improve understanding of these events and provide more information for management and control practices.

Французский. La gestion des milieux aquatiques touchés par des proliférations végétales rencontre de nombreuses difficultés liées à l'appréciation des déséquilibres induits. Un inventaire des principaux groupes végétaux concernés, considérés comme des "espèces à risque de prolifération" a été dressé après examen de divers constats recensés sur le territoire français. Les milieux propices aux proliférations présentent des conditions environnementales particulières : fort éclairement souvent lié à une faible profondeur et à un échauffement des eaux, conditions hydrologiques stables, minéralisation moyenne à forte, niveau trophique souvent élevé. La conjonction de ces deux composantes (espèce à risque et milieu propice), créé ainsi les conditions d'une prolifération et définit des situations à risque minimal ou maximal.