Terrestrial Palaeoecology and Global Change

Chapter 8. Ecosystem evolution
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– The mid-Jurassic of Ust-Baley, Angara River (Heer, 1868-1883, Krassilov &
Bugdaeva, 1988 and unpublished),
– The Early Cretaceous of Bureya, Russian Far East (Vakhrameev & Doludenko,
1961; Krassilov, 1972c, 1973c, 1978a),
– The Late Cretaceous of Sakhalin (Krassilov, 1979),
– The Early Palaeocene of Amur Basin (Krassilov, 1979).
All these are similarly positioned north of the evergreen/deciduous boundary for respective
geological epochs.
Species richness (y). Fig. 117 represents the diversity estimates for the northern
nemoral zone over a sequence of geological epochs, Permian to Palaeogene, based on
the species–area equation, with (x) defined by the sequential positions of the evergreen/
deciduous ecotone, (a) derived from six well-known taphofloras of respective ages and
(z) extrapolated from the modern analogue. Fluctuations of standing crop diversity seem
to have reflected a combined effect of climate change (temperization in the Permian,
mid-Jurassic and Early Palaeocene) and the boreal transgressions (maximal in the Late
Cretaceous).
Fig. 117. Species richness estimates for the northern nemoral zone based on the species–area equation y = ax z ,
with the areas (x) shown in Fig. 99, the spatial heterogeneity constant (z) extrapolated from the modern
analogues (0.18, a higher value for the present-day nemoral vegetation), and the basinal diversity (a) derived
from representative taphofloras: (P2) Mid- Permian of Fore-Urals (Naugolnykh, 1998), (T1-2) Early –
Middle Triassic of Tunguska Basin and Taymyr (Mogucheva 1973; Sadovnikov, 1997), (J2) Mid-Jurassic of
Ust-Baley, Angara River (Heer, 1868-1883, Krassilov & Bugdaeva, 1988 and unpublished), (K1) Early
Cretaceous of Bureya, Far East (Vakhrameev and Doludenko, 1961; Krassilov, 1972c, 1973c, 1978a), (K2)
Late Cretaceous of Sakhalin (Krassilov, 1979), (KT) Early Palaeocene of Amur Basin (Krassilov, 1979).