Vitality structure of Allium angulosum L. (Alliaceae) coenopopulations in the floodplain of the upper reaches of the Severnaya Dvina River (Vologda region)

A comprehensive research of rare and endangered species plays an important role in the conservation of biological diversity. They are the most vulnerable components of biocenosis. An important part of their comprehensive research is the assessment of the coenopopulation vitality. Vitality of individuals is the most sensitive to adverse factors. The investigation of Allium angulosum L. is an acute task. It is a rare species included in the Red Data Book of Vologda region. It needs biological control in its territory. The aim of this work was to assess the vitality of A. angulosum coenopopulations in the communities of the floodplain of the upper reaches of the Severnaya Dvina river (North-Eastern part of Vologda region). During the search routes, we discovered two A. angulosum coenopopulations. One of them is located on the right bank of the Severnaya Dvina river (60°47'50"N, 46°26'20"E). Another coenopopulation is located on the right bank of the Shemogsa river (60°50'37"N, 46°29'35"E). We described the communities in the locations of the coenopopulations using the method of YuN Neshataev (1987). We estimated ecological conditions of habitats using H. Ellenberg's scales (1991), on the basis of the projective cover of the species found in the communities. We investigated the number and density of the coenopopulations using traditional methods (Rabotnov, 1950; Zhukova, 1995).The cenopopulation vitality structure was investigated using the method of calculating the IVC index (Ishbirdin, Ishmuratova, 2004) and the method of calculating the Q index (Zlobin, 2009). The areas of A. angulosum coenopopulations are about 20-30 square meters. They have similar demographic structure. Their number is about 300 shoots and their density is 10-16 shoots per one square meter, the coefficient of generativity is from 40 to 50%. They are located in communities characterized by different biotic conditions. The values of the IVC indexes of these coenopopulations indicate that the conditions for this species are more favorable in the community, where the first coenopopulation is located (See Table 2). In this coenopopulation the individuals of the higher and intermediate class vitality constitute 83%. The Q index of the vitality of this coenopopulation is greater than the proportion of the individuals of the lower class vitality in it (See Table 2). It shows favorable conditions for the growth of the species in this community. In another coenopopulation the individuals of lower-class vitality constitute 77%. The Q index of the vitality of this coenopopulation is 7 times less than the proportion of individuals of the lower class vitality in it (See Table 2). This indicates unfavorable conditions for the growth of the species in this community. The main reason for different level of individual vitality in these populations is interspecific competition influencing the conditions of the environment (lighting and other). The consequence of it is a different level of seed productivity of individuals and the quality of seeds they produce in these conditions (See Table 4). In the first coenopopulation A. angulosum seeds have higher germination and germination energy than its seeds in the second coenopopulation (See Table 5). It increases the role of seed reproduction in the self-maintenance of this coenopopulation. The article contains 5 Tables, 37 References.

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