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Ecological Characteristics of Aristida Longiseta and Agropyron Spicatum in West‐Central Idaho
Author(s) -
Evans G. R.,
Tisdale E. W.
Publication year - 1972
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1935719
Subject(s) - agropyron , germination , biology , ecology , phenology , botany , agronomy
Germination requirements, root development, phenology, and the effects of moisture—saturated soils were studied in Aristida longiseta and Agropyron spicatum. Agropyron germinated well at temperatures of 20°—22°C, but Aristida showed little response until temperatures were increased to 40°C. Prior stratification at 0°C had no appreciable effect on germination of either species. Rapid primary root elongation enabled Aristida to establish itself in droughty habitats, but saturated soils strongly inhibited its growth. In the field A. longiseta starts growth late in the spring, develops at a rapid rate, and flowers 10 days later than A. spicatum. The seed of Aristida matures slowly and is shed in September. Fall regrowth, which occurs normally in A. spicatum, is rare in A. longiseta. The hypothesis is developed that excessive grazing has so reduced the abundance of A. spicatum that A. longiseta has been able to replace it and form long—lived communities.