I don't think there is going to be much immigration to Russia for a long time. According to Richard Pipes in
The Russian Revolution, it seems paradoxical, but as huge as Russia was, it was suffering from overpopulation--which makes the idea of it receiving substantial numbers of immigrants rather fanciful (what it actually needed was more of its own peasants emigrating):
"The explanation of this seeming paradox lies in the fact that in agricultural countries population densities acquire meaning only by relating the number of inhabitants to that share of the territory which is suitable for farming. Viewed in these terms, Russia was hardly a country of boundless expanses. Of the 15 million square kilometers of European Russia and Siberia, only 2 million could be cultivated and another 1 million used for pasture. In other words, in the homeland of the Great Russians, only one square kilometer out of five was suitable for agriculture. Once allowance is made for this fact, the figures for Russian population densities change dramatically. In Siberia, the average density in 1900 was 0.5 per square kilometer, a negligible figure. In the fifty provinces of European Russia, it rose to 23.7 per square kilometer, which exceeded slightly the figure estimated by economic geographers to be optimal for the region.* But even this figure misleads because it includes the sparsely populated provinces of northern Russia. The regions which really mattered, because they held the great mass of Russian peasants, were the central provinces, and here the population density ranged from 50 to 80. This figure matches that of contemporary France and exceeds that of Ireland and Scotland. In other words, had St. Petersburg given up Siberia and the northern provinces, its population densities would have equaled those of Western Europe.
"Densities of this magnitude might have proven tolerable were it not for pre-revolutionary Russia’s extraordinary population growth. With an annual excess of births over deaths on the order of 15 per 1,000, Russia had the highest rate of natural increase in Europe.† The implications of such a rapid population growth for agriculture can be demonstrated statistically. In the Empire of 1900, three-quarters of the population was employed on the land. With an increase of 15 per 1,000 each year and a population of 130 million, 1,950,000 new inhabitants were added annually, 1,500,000 of them in the countryside. Allowing for the very high infant mortality rate, we are left with a million or so additional mouths which the countryside had to feed each year. Given that an average Great Russian household had five members and tilled ten hectares, these figures mean that Russia required annually an additional 2 million hectares of arable land.‡
"In Western Europe, the pressures generated by a somewhat smaller but still rapid population growth from the middle of the eighteenth century onward was solved in part by overseas migration and in part by industrialization...
"Russia had neither safety valve. Her citizens did not migrate abroad: they preferred to colonize their own country. The only significant groups to leave Russia were non-Russians from the Western provinces...
"Nor could Russian industry absorb significant numbers of excess peasants. In the 1880s and even more so in the 1890s, rapid industrial growth led to a rise in industrial employment: in 1860, Russia had 565,000 industrially employed, and in 1900, 2.2 million (of the latter, about one-half were factory workers).17 Using the same figures for households as above, this means that during the closing four decades of the nineteenth century, the number of Russians freed from dependence on agriculture grew from 3 to perhaps as much as 12 million. But with an annual accretion of 1 million rural inhabitants, it also meant that industry at best absorbed from the land one-third of the new population."
http://www.rulit.me/books/the-russian-revolution-read-291095-41.html
http://www.rulit.me/books/the-russian-revolution-read-291095-42.html