Establishing winterfat in prairie restorations in Saskatchewan

The importance of native shrubs in the Northern Mixed Prairie of Canada has generally been overlooked; however, restoration specialists have recognized the importance of including shrubs in prairie restorations. Emergence and establishment of winterfat (Krascheninnikovia lanata (Pursh) A. D. J. Meeuse & Smit), a palatable and long-lived shrub, was evaluated in relation to planting time and seedbed preparation in swards of native grasses that had been seeded on previously cultivated cropland in the prairie ecozone of southern Saskatchewan. Diaspores of winterfat were broadcast at 20 m-2 in autumn or spring on upland and lowland sites in seedbed treatments including (1) a control or undisturbed sward, (2) mowing the sward to a 15-cm height, (3) haying, (4) glyphosate application after haying and, (5) tillage. Emergence of winterfat on upland and lowland sites was about three-fold greater with autumn than with spring planting (P < 0.01). Winterfat establishment on upland sites was affected by the interacting influences of planting times and seedbed treatments (P = 0.01), with most winterfat establishing from autumn sowing in the glyphosate and tillage treatments (2.1 and 2.2 plants m-2, respectively). Establishment of 0.9 plants m-2 from autumn planting was greater (P < 0.01) than the 0.1 plants m-2 establishing from spring sowing on lowland sites. The interaction of planting date and seedbed treatment on lowland sites did not influence winterfat establishment (P = 0.06) nor did seedbed treatments (P = 0.07). Winterfat should be planted in late autumn as opposed to spring. Key words: Ceratoides lanata, Eurotia lanata, Krascheninnikovia lanata, Northern Mixed Prairie, restoration

Action of plant growth regulators and salinity on seed germination of Ceratoides lanata

Ceratoides lanata (Pursh) J.T. Howell is a shrub with numerous annual branchlets from the family Chenopodiaceae and is widely distributed in brackish water playas of northern Utah. Seeds had no dormancy, and about 90% of the seeds germinated in nonsaline control. Seed germination decreased with the increase in salinity, and more than 10% of the seeds germinated at 900 mmol/L NaCl. Almost all seeds germinated in less than 24 h, and no additional seed germinated after this time. Gibberellic acid had no effect in alleviating salinity effects; however, kinetin and fusicoccin substantially alleviated the effect of salinity on germination, while ethephon almost completely reverted the effect of salinity.Key words: Ceratoides lanata, gibberellic acid, ethephon, fusicoccin, halophytes, kinetin.

Can shrub cover increase predation risk for a desert rodent?

Previous research indicates that predation risk may influence activity patterns, habitat partitioning, and community structure of nocturnal desert rodents. Shrub microhabitat is typically considered safer than open microhabitat for these small mammals. We investigated predation risk for Townsend's ground squirrels (Spermophilus townsendii), which are diurnal desert rodents that detect predators visually and use burrows for refuge. Our results suggested that shrub cover may increase risk for these squirrels by decreasing their ability to escape from predators. Our field experiment indicated that running speeds of juvenile squirrels were lower in shrub (Ceratoides lanata) habitat than in open areas. Shrub cover was also associated with shorter predator-detection distances (mammalian and avian) and fewer refuges (burrow entrances per hectare) than in open areas in one year but not in another. Our study demonstrated that the visual and locomotive obstruction of vegetative cover may increase predation risk for diurnal desert rodents and that elements of habitat-dependent risk may be temporally dynamic.

Mulch Effects on Crown Growth of Five Southwestern Shrub Species

Effects of pine bark mulch on crown growth of cliffrose (Cowania mexicana var. stansburiana Torr.), curlleaf mahogany (Cercocarpus ledifolius Nutt.), desert olive (Forestiera neomexicana Gray), Apache plume (Fallugia paradoxa D.Don), and winterfat (Ceratoides lanata Pursh.) were examined. Three depths of mulch 0, 7.5, and 15 cm (0, 3, and 6 in), were applied to 3.8 liter (1 gal) plants at time of planting (April, 1989). Height, width, stem diameter and foliage fill were recorded for each plant after 18 months. Foliage fill was obtained by digital image analysis of 35 mm photographic slides. Mortality was recorded at the conclusion of the study. Results indicated no treatment differences within species in their growth or mortality after 18 months. Soils were examined within three soil layers (0–5 cm, 5–15 cm and 15–30 cm depths) for electroconductivity and pH. Soil pH was not affected throughout the profile but was lower in the surface soil layers under mulch. Soil EC in the top soil layer was reduced under mulching depending on species. The benefit of pine bark mulching is not apparent in the crown growth of these species. Growth form and native environment of individual species should be considered in mulching recommendations.

Some occurrences of vesicular–arbuscular mycorrhiza in natural and disturbed ecosystems of the Red Desert

Studies have been initiated on the occurrence of vesicular–arbuscular mycorrhiza (VAM) in plant communities of revegetated mine spoils and undisturbed areas of the Red Desert of Wyoming. It was found that the majority of plants in undisturbed environments in this area are mycorrhizal. On disturbed sites, no mycorrhiza were encountered. Of interest for both the undisturbed and disturbed communities was the predominance of plants belonging to the family Chenopodiaceae. The major difference between the plant species encountered in each community is associated with their reproductive strategy, as well as whether the plants possessed VAM. The major species encountered on undisturbed sites are Atriplex gardneri, At. confertifolia, Ceratoides lanata, Grayia spinosa, Kochia americana, and Sarcobatus vermiculatus, all possessing mycorrhiza. Halogeton glomeratus predominated in disturbed sites and did not possess VAM. The role of VAM in both succession and reproductive strategies of plants is also discussed.