Terrestrial Palaeoecology and Global Change

2 Valentin A. Krassilov. Terrestrial Palaeoecology
Fig. 1. Dead mass export from terrestrial ecosystems to the atmosphere, continental traps and the ocean.
mats, spore-pollen assemblages or structureless particles. All ecosystems produce dead
mass that is, in variable proportions, recycled, accumulated in a not readily accessible form
and exported (Figs.1, 2). It is well-known that terrestrial ecosystems differ both in absolute
and relative (to their standing biomass) amount of exported dead mass, which correlates
with biological diversity and population strategies, in turn depending on environmental stability,
climate (temperate ecosystems are, as a rule, more prolific dead mass exporters than
tropical ecosystems) and developmental stage (pioneer/seral communities export more
dead mass relative to their standing biomass than climax stages).
The primaeval terrestrial ecosystems dominated by heterotrophic organisms might
have depended not so much on their own primary production (of the cyanophytic–algal
films on regolithic rock surfaces) as on the import of organic matter, such as air-borne
spores of semiaquatic plants that appeared in the mid-Palaeozoic fossil record before
the land plant macrofossils. The first traces of pedogenesis (known since the Ordovician
or even earlier: Retallack et al., 1984; Retallack, 1986a) might be due to imported
biomass and heterotrophic production. The role of primary production increased with
land plant evolution, making terrestrial ecosystems the major exporters of organic matter,