Moisture Relationships in Twelve Northern Desert Shrub Communities Near Grand Junction, Colorado
Citation
F A Branson, I S McQueen, and Reuben F Miller, Moisture Relationships in Twelve Northern Desert Shrub Communities Near Grand Junction, Colorado: .
Summary
Twelve northern desert shrub communities having the same macroclimate but differing habitats were studies. Arranged in order of decreasing production of live stems plus current growth, the communities were: (1) Sarcobatus vermiculatus (9,172 kg/ha), (2) Grayia spinosa (7,412 kg/ha), (3) Artemisia tridentata (5,474 kg/ha), (4) Chrysothamnus nauseosus (4,836 kg/ha), (5) Atriplex confertifolia (3,194 kg/ha), (6) Eurotia lanata (2,026 kg/ha), (7) Hilaria jamesii-Atriplex confertifolia (1,995 kg/ha), (8) Atriplex corrugata (1,949 kg/ha), (9) Chrysothamnus greenii filifolius (1,866 kg/ha), (10) Atriplex nuttallii (1,309 kg/ha), (11) Elymus salinus (865 kg/ha), and (12) Tetradymia spinosa (564 kg/ha). The communities were relatively simple [...]
Summary
Twelve northern desert shrub communities having the same macroclimate but differing habitats were studies. Arranged in order of decreasing production of live stems plus current growth, the communities were: (1) Sarcobatus vermiculatus (9,172 kg/ha), (2) Grayia spinosa (7,412 kg/ha), (3) Artemisia tridentata (5,474 kg/ha), (4) Chrysothamnus nauseosus (4,836 kg/ha), (5) Atriplex confertifolia (3,194 kg/ha), (6) Eurotia lanata (2,026 kg/ha), (7) Hilaria jamesii-Atriplex confertifolia (1,995 kg/ha), (8) Atriplex corrugata (1,949 kg/ha), (9) Chrysothamnus greenii filifolius (1,866 kg/ha), (10) Atriplex nuttallii (1,309 kg/ha), (11) Elymus salinus (865 kg/ha), and (12) Tetradymia spinosa (564 kg/ha). The communities were relatively simple in terms of plant composition; the dominants in many of them contribute > 90% of the plant cover. Seasonal patterns of both internal-plant stresses and soil-moisture stresses were measured. Both sets of values increased from late May until early September when increases in rainfall caused both to decrease. Minimum internal-plant stresses were similar for all species but maximum values differed greatly. Maximum plant-stress value ranged from 103 bars for A. nuttallii to only 40 bars for C. nauseosus. Internal-plant stresses were closely related to minimum soil-moisture stresses found within soil profiles at the time of sampling. The relationship was good for upland species but poor for species in moist habitats. Similar close relationships were found for internal-plant stress and quantities of moisture stored in soils. Correlation coefficients for internal-plant stress vs. wind and atmospheric stress were low and nonsignificant, but air temperature was significantly correlated with plant stress in several species. Evapotranspiration from the 12 communities ranged from 60 mm for the C. greenii filifolius habitat to > 130 mm for the G. Spinosa habitat. Evapotranspiration was significantly related to percent live cover (r = +.84**). Soil salinity at field-capacity values ranged from > 16 bars to < 1 bar; only 5 of the 12 habitats had saline soils. The highest root mass (2,547 kg/ha) was in the C. nauseosus nauseosus soil--the lowest (569 kg/ha) in the A. corrugata soil. Efficiency of water use (plant growth per unit of water used) was lower for species occupying dry habitats than for those in moist habitats. Phenological observations showed that most species occupying moist habitats continued active growth for longer periods. A study of persistence of leaves showed 10% annual loss of leaves in A. corrugata. Ninety percent of leaves of this species were retained throughout the season whereas < 20% of marked leaves were retained by A. tridentata and A. nuttallii.
Published in Ecology, volume 57, issue 6, on pages 1104 - 1124, in 1976.
