Effective conservation requires a good understanding of factors causing variation in population growth rate. We here analyse the relationship between female age and fecundity in the saiga antelope Saiga tatarica tatarica, a critically endangered ungulate of the Eurasian steppes and semideserts, at both individual and population levels. Annual variation in age structure and twinning rates was investigated using long-term datasets, sampling a total of 3308 females in four populations over more than 40 years. Further, a new non-invasive method is presented, estimating twinning rates from both calves and placentas encountered during calving aggregation transects. At an individual level, the most parsimonious model for twinning rates included three age classes (1, 2 and Z3 years); however, the model with only two classes (1 and Z2 years) was competitive and particularly useful for monitoring because these two age classes can reliably be determined by direct observation in the field. Among yearlings, 77.4% were fecund and 11.7% twinned, whereas among older females 94.6% were fecund and 72.6% twinned. At a population level, annual variation in age structure (proportion Z2 years) correlated well with annual variation in twinning rate except in the north-west PreCaspian population. Our results suggest that the recent poaching-driven collapse in saiga numbers has potentially resulted in reductions in fecundity, which will have an impact on population growth rate. Our results highlight the potential for monitoring of twinning rate using non-invasive calving aggregation transects as a cost-effective additional tool to population counts for monitoring the status of this critically endangered species. These monitoring methods are also potentially transferable to other ungulate species.

The destruction of natural ecosystem resulting in reduction or even destruction of saiga habitat is the consequence of anthropogenic impact. The degradation of pasture ecosystem in Kalmykia reached a crucial level and the republic was announced as the disaster zone in 1988. The year 1998 witnessed the reduction of saiga population size from 220 thousand to 55 thousand animals. Registration works in 2014 showed further reduction of saiga to 12 thousand- 12.8 thousand animals. In general, the population of saiga in the North-Western Caspian region continues to be in depression despite low losses of new born saiga (6.2%). The degradation of pastures led to the next stage of population cycle characterized by lower reproduction ability of animals and high level of mortality. This process deteriorates due to worse living conditions during some seasons as well as by decreasing the ability of pastures to give feed.

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More and more evidence has proven that nutritional issues are serious enough and malnutrition can lead to health deterioration of the working-age population and the country can face a decrease in life expectancy. The study of lifestyle of the working population and nutritional analysis of their diet found that the country needs to find proper diet for them. The problem can be solved by developing the technology for new products that contain necessary nutrients and low calories which reduce the overall load on the diet. The principles of functional nutrition developed in foreign countries can serve as a basis for a new direction of development.

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