http://hdl.handle.net/10150/635459 2026-03-07T14:21:45Z 2026-03-07T14:21:45Z http://hdl.handle.net/10150/650586 2020-12-23T01:30:36Z 2001-05-01T00:00:00Z

Journal of Range Management, Volume 54, Number 3 (May 2001) Complete digitized issue.

2001-05-01T00:00:00Z Van Ommeren, R. J. http://hdl.handle.net/10150/643874 2020-09-24T01:38:40Z 2001-05-01T00:00:00Z

Species composition on reclaimed ski runs compared with unseeded areas Van Ommeren, R. J. The cover of native and non-native introduced plants was compared between seeded (reclaimed) ski runs and adjacent or nearby unseeded (control) areas at a managed ski area in northern Arizona to determine the potential effects of revegetation efforts on plant species composition of the area. Although vegetative cover was similar, plant species richness was significantly lower on reclaimed ski runs compared with control areas. At 3 of 4 sites, the number of plant species was more than 2-fold greater in control areas, although species richness was similar between control and reclaimed areas at 1 site. The proportion of native species was more than 3-fold greater in control areas compared with reclaimed ski runs. The proportion of non-native species was more than 5-fold greater on reclaimed ski runs than in control areas. Although sites differed substantially in time since seeding, no evidence was found at 3 of the 4 sites for either an invasion of non-native species into the native plant community, or significant re-establishment of native species in reclaimed areas. Relatively high biomass of native species on a reclaimed ski run at 1 site appeared to be tied to a low level of initial disturbance and favorable conditions for growth. Results suggested that minimizing initial soil disturbance, retaining topsoil, and maintaining islands or patches of natural vegetation within cleared areas promoted the re-establishment of native species on ski runs.

2001-05-01T00:00:00Z Kitchen, S. G. Monsen, S. B. http://hdl.handle.net/10150/643873 2020-09-24T01:38:27Z 2001-05-01T00:00:00Z

Forage kochia seed germination response to storage time and temperature Kitchen, S. G.; Monsen, S. B. The Eurasian low-shrub, forage kochia [Kochia prostrata (L.) Shad.], was introduced into western North America for use in restoration of severely disturbed landscapes in arid and semiarid environments. Seed mature in late fall and are short-lived in typical warehouse conditions. In a preliminary, cold-temperature experiment (2 degrees C) using 3-month-old seed from 16 forage kochia accessions, mean germination time, expressed as days to 50% germination, varied from 4 to 88 days. Follow up experiments using seed of 5 accessions tested the effects of storage time and temperature on seed viability and mean germination time and related this to field planting success. Sub-samples were air-dried and stored in plastic bags in a freezer, cold room, and lab (-15, 2, and 20 degrees C respectively). A fourth set of subsamples was stored in a shed with no temperature control (simulated warehouse storage). Seed were tested fresh and retested after 4, 8, 12, 24, and 36 months of storage. Mean viability decreased from 77% (range 66 to 93%) for recently harvested seed, to 24 and 8% for lab- and shed-stored seed, after 36 months of storage. No significant change in viability was observed for cold room- and freezer-stored seed. Across all accessions, cold temperature mean germination time (MGT) for recently harvested seed was 73 days (range 51 to 109 days). For each accession, germination occurred primarily over a 70 day period. Mean germination time decreased as storage time increased for lab- and shed-stored seed, varied unpredictably for cold room-stored seed, and remained unchanged for freezer-stored seed. Field germination using 1- and 2-year old lab- and shed-stored seed was significantly faster than that of same-aged cold room- and freezer-stored seed. The number of live seedlings 4 months after planting for cold room- and freezer-stored seed was 10-fold or greater than that of lab- and shed-stored seed. Thus a delayed, asynchronous cold-temperature germination pattern appears to be adaptive for forage kochia establishment. Cold, dry storage prevents loss of seed viability and preserves this desirable germination pattern.

2001-05-01T00:00:00Z Hild, A. L. Karl, M. G. Haferkamp, M. R. Heitschmidt, R. K. http://hdl.handle.net/10150/643872 2020-09-24T01:38:09Z 2001-05-01T00:00:00Z

Drought and grazing III: Root dynamics and germinable seed bank Hild, A. L.; Karl, M. G.; Haferkamp, M. R.; Heitschmidt, R. K. Drought and herbivory frequently influence North American rangelands. While these influences may temporarily reduce vegetative cover, their mutual influence on the available seedbanks which might occupy new safe sites is unclear. We examine effects of drought and grazing upon pre- and post-drought plant root distribution and germinable seed bank to determine 1) if the response of root distributions to drought depends upon grazing use and 2) if the presence of germinable seeds is altered significantly by drought and grazing. Using twelve, 5 X 10 m non-weighing lysimeters with an automated rainout shelter, we documented root intercepts in situ using a minirhizotron from 1993-1996. Seed bank samples were incubated in a greenhouse to determine seedling emergence. Roots were fewer in shallow soil layers in grazed plots than ungrazed plots by the end of the study, irrespective of drought. Roots in deeper (Bw horizon) soil layers were fewer during drought, but were not influenced by grazing. Seed bank composition results suggest that perennial grasses were a small portion of the seed bank. Cool-season annual grass seeds accumulated after drought. Without drought, forb seed banks increased with grazing. Thus while shallow roots may decrease during drought, in the year following drought grazing may decrease aboveground net primary production, and allow large accumulations of cool-season annual grass seed in a northern mixed grass prairie.

2001-05-01T00:00:00Z