Trapa natans
Trapa natans L.
Trapaceae – Water caltrop family
Conservation status. Endangered [EN B2ab(i,ii,iii,iv,v)]. BDA, BC. Tertiary relic.
Morphology and biology. Aquatic annual with thin main root and numerous of adventitious roots. Leaves submerged, pinnate to filiform and floating – forming rosette on the water surface, usually rhombic to rounded, petioles with a fusiform swelling. Flowers with pedicels, in the axils of the floating leaves. Corolla with 4 white or yellow white petals. Fruit uni-loculate, rare bi-loculate drupe with horn-like, cuneate projections with fleshy pericarp that decomposes in the water. Fl. VII–VIII, fr. VIII–IX. Reproduction by seeds.
Habitats and populations. Bogs, floods of the rivers with both fresh and semi-salty water. In the recent past formed a population with significant density (Svistovska Balta, Belene and Kozloduy marshes, Central Balkan). In the recent time most of the old localities are destroyed. Can be seen as separate individuals or in small groups also in draining canals and fish farms. The size of the populations greatly varies in the years.
Distribution in Bulgaria. Black Sea Coast, Northeast Bulgaria, Danubian Plain, Forebalkan, Balkan Range (Eastern), Rhodopi Mts (Eastern), Thracian Lowland, Strandzha Mts (near Yasna Polyana dam); from 0 to 400 m alt.
General distribution. Europe, Mediterranean region, Japan - Chinese region, SW Asia.
Threats. Loss-deterioration of habitats – draining of marshes and mires; climate change, global warming, acid rains, aggressive water tourism.
Conservation measures taken. Protected species according to the national Biodiversity Act. Some of the localities are within Dzholyun Gyol Protected Site, Blatoto Alepu Nature Monument and some others as well as in site of the European ecological network Natura 2000 in Bulgaria. A program for reintroduction of the species in Persinski marshes is being implemented.
Conservation measures needed. Study of the size and area of the populations, restoration of canals and Danubian marshes.
References. Peev 1979, 1984; Petrova et al. 2004; Tzonev 2004; Petrova 2010.
Authors: Dimitar Peev & Sonya Tsoneva
