Role of the Regime of Ecosystem Use in the Variability Structure of Some Seed Productivity Traits of Mongolian Milkvetch, an Endemic Plant of the Republic of Dagestan

A comparative analysis and an evaluation of the structure of variability have been carried out for eight (dimensional, numerical, weight, and index) seed productivity traits of two populations of Mongolian milkvetch ( Astragalus fissuralis Alexeenko (Fabaceae)) growing at two different altitudes (1100 and 1750 m above sea level) in the middle mountain belt of the Inland Mountain Dagestan. This vegetatively mobile dwarf shrub is included in the Red Books of Russia and the Republic of Dagestan. The study was arranged at the population level. Total statistics, correlation analysis, and analysis of variance were used to determine and evaluate differences in the average values of the studied traits and the impact of an anthropogenic factor (ecosystem-use regime) on the variability of those seed productivity traits directly related to the adaptive strategy. Under relatively unfavorable natural conditions, plants of this rare species form short pods that usually have one or two seeds, in contrast to introducers. At the same time, the proportion of weight traits related to the adaptive (reproductive) strategy and reproductive-effort efficiency (seed weight, weight of seeds in a pod, and the percentage of seed weight directly intended for the reproduction process) is higher in the natural environment than under the conditions of protected areas. However, it was noted that the plants in the more favorable conditions of experimental plots located at two experimental bases of the Mountain Botanical Garden (Dagestan Scientific Center of the Russian Academy of Sciences) develop their vegetative mass and increase their size (pod length) and number (number of relatively lightweight and small seeds). As a result, changes in weight characteristics, such as increased seed weight, are observed. In other words, the introduction of plants increases of pod size, while the weights of pods and seeds increase under natural conditions. The ecosystem-use regime significantly impacts the variability of reproductive traits; the strength of such impact varies from 23.6 to 79.3%.