Mallory

[JoatSimeon at aol.com]

What we refer to as "pastoralism" is generally thought of as the type
practiced in areas of the Eurasian steppe that weren't ecologically suitable
for agriculture.  Grazing, including transhumant grazing, was part of
agricultural systems everywhere in the area, but that's not the same thing as
being primarily dependent on the herds of the grasslands.

Pastoral nomads usually had a routine of movements, summer-winter, or
altitudinal ones in areas with mountains, to take advantage of ecological
variations.

However, the Eurasian semi-arid and arid steppe zone is ecologically marginal
-- and so is subject to unpredictable shifts; severe and long-lasting
droughts, for example, which can abruptly reduce the carrying capacity of the
pastures.

The more purely pastoral and nomadic the economy, the more vulnerable it was
to such shifts; and the general human tendency to gradually breed up to and
slightly beyond the carrying capacity of the environment was also relevant.

Since the Eurasian nomads become more specialized in pastoralism over the
millenia, they became at once more efficient users of this marginal
environment (and more able to exploit all of it), and at the same time more
vulnerable to its instability.  Not coincidentally, the violence and scale of
population movements in the steppe zone also increased over time, building up
to the all-time climax of the 13th and 14th centuries, when single steppe-
based empires could span the whole area from Hungary to Manchuria and invade
places as far away as Burma and India.

The situation in early PIE times, when the _first_ semi-pastoralists were
expanding through the _margins_ of the steppe zone (the forest-steppe and
river valley areas, for instance), and doing so with populations of humans and
livestock well below the maxima, was historically unique.  Never again would
this territory be so 'open' (inhabited only by very thinly scattered hunter-
gatherers).