Tuesday, July 11, 2006

Minimum Viable Population, and Implications for a Model Settlement (plus see substantive comments)

The minimum viable population is a measure of the minimum genetic diversity required to sustain a population indefinitely. Too few individuals endangers the survival of the population. Obviously, harmful, recessive mutations are more likely propagated in small populations, but small populations are also more vulnerable than large ones to all kinds of stochastic dangers, such as too many members of a given generation being born of only one sex.

The minimum viable population has implications for Eschaton management. The population supported by a post-Eschaton society must be equal to or greater than the minimum viable population number. Some have estimated the number to be as few as 500 individuals; however, some research suggests that the proper number is at least in the thousands and probably in the tens of thousands.

It is difficult to imagine a single post-Eschaton, agricultural city with a population in the tens of thousands. I propose a model of post-Eschaton reconstruction that emphasizes small, self-sufficient, agricultural settlements, with one or more self-sufficient University-style settlements dedicated to research, technology preservation, and training.

Consider, for instance, the amount of land necessary to supply the caloric needs of 30 people. The most calorie-intensive crop (by cultivation area) is the potato. The bare calorie needs of a single individual may be supplied by as few as fifteen five-feet-by-twenty-feet (one hundred square feet) beds of nothing but potatoes, as opposed to several times that area for wheat or beans. Allowing for other nutrition needs, a measure of surplus, and food for visitors and animals, it would be unwise to posit fewer than thirty five-by-twenty-feet beds per individual. In a settlement of thirty people, this makes nine hundred beds, for a total area of at least two acres of nothing but biointensive garden beds (not counting walking space).

A post-Eschaton settlement will have to defend its cultivated land and growing crops from raiders (and other pests). Small, two-acre plots are one option; massive, hundred-acre plots are another. Widely dispersed, smaller plots have a defense advantage in that they are less concentrated and each plot is less appealling to target; also, there is less area to defend. (Larger plots, of course, have a lower perimeter-to-area ratio, which may be desirable in some defense circumstances.)

I propose to work with the small, self-sufficient, University-style settlement model. My ideal University is a unit of 30-100 individuals who produce all of their own food plus a surplus, research and preserve foundational technologies, and train individuals in the foundational technologies. Individuals would spend time in the University, and would then go out into the post-Eschaton world and assist, or even found, self-sustaining settlements. Social and economic assimilation would be an absolute necessity for the maintenance of human civilization under this model.


Anonymous thinman said...

If the minimum number of people is derived frm a need for genetic diversity, does it help at all if there's suddenly a high background level of radiation? Making the minimum viable population smaller in a post-nuke situation?

Maybe this is the dumbest thought ever.

July 12, 2006 11:10 AM  
Blogger Curator said...

Interesting. I think it doesn't help, because random mutations are almost always harmful. Only genetic diversity that has been validated by surviving, reproducing phenotypes is probably valuable. Who knows, though? I mean, one mutation allowing telephathy or psychokinetic pants-shitting, and the human race is onto a whole new track.

July 12, 2006 1:43 PM  
Anonymous Ho Sokrates said...

A few questions.

What is the connection between the minimum viable population and the model settlement? If the minimum viable pop was greater or lesser, would that change the settlement types? If so, how? It seemed like what affected model settlements was more crop land.

For crop types, soil type and weather are crucial, right? Potatoes don't grow everywhere equally well. And for all we know the catastrophic event could change the climate, so it seems wise to be prepared for a number of different options. I would think that in preparation you would want a number of different seeds available to see what does well in the environment you end in.

Also, how easy would it be to set up bio-intensive farming beds? I'm not sure what exactly that involves, but a lot of moderning farming, I assume, wouldn't be available (chemical fertilizers, super advanced seeds, etc.).

July 16, 2006 1:06 PM  
Blogger Curator said...

Mr. Sokrates, thank you. The presence of analytical philosophers is always an insurer of the rigor of one's work.

Regarding the connection between the minimum viable population and the size of a model settlement: First, if the available population (throughout the whole region of the world) is below about 1000, long-term survival of the population is all but impossible, and the survivors should probably focus on living out the remainder of their lives in comfort (and using up limited food and medical supplies for humanitarian purposes rather than attempting to rebuild a lasting civilization). Second, I don't think I need to provide evidence that the larger a settlement is, the more economically and socially complex it must become. (Extreme concentration of population, a la Los Angeles, being a logistical nightmare.) A very small (workable, self-sufficient, productive) city wouldn't have the numbers to survive in the long term, but a city with a population large enough for that may not be practicable by the immediate survivors of an Eschaton event. A middle ground (though not the only solution) is to set up small settlements, but use them as bases for creating and supporting other small settlements throughout the region. All the settlements together would function as a population.

Regarding biointensive agriculture - it is actually one of the lowest-tech methods of farming in terms of chemicals and tools. I will provide an overview of this method in a later post. Thank you for your comments!

July 20, 2006 2:47 PM  
Blogger Shane said...

I have a small problem with the idea of a less than 1000 pop changing focus from survival to comfort. After an eschaton event small pockets of humanity may be spread across the whole fo the world, these cashes would have no way of knowing how many others are alive. It would be best, considering all outcomes, to assume that a viable population exists to support prosterity. Also if we reject the many of the social mores that we are accustomed to I think the population could be quite a bit smaller than 1000...if inbreeding and hard nose selectivity were to be utilized.

April 02, 2008 6:40 PM  

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