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Brigham Young University (2011)

Scarification and Cultural Practice of Four Lupine Species Native to the Great Basin

Jones, Covy Dennis

Titre : Scarification and Cultural Practice of Four Lupine Species Native to the Great Basin

Auteur : Jones, Covy Dennis

Université de soutenance : Brigham Young University

Grade : Master of Science 2011

Résumé
The Great Basin is North America’s largest desert, encompassing 135 million acres. Grazing and other anthropogenic activities in the Great Basin have put heavy demands on the landscape over the last 150 years. Heavily grazed areas lack diversity which allows the spread of exotic weed species. Cheatgrass (Bromus tectorum L [Poaceae]) has invaded and shortened fire frequency intervals from historic 30—100 years to as few as three to five years. Post-fire reseeding of native species is requisite for restoration of highly invaded ecosystems thus, preventing complete conversion to exotic weeds. Most native shrubs and grasses are available for restoration projects, but native forbs are largely unavailable or expensive. This situation led to the creation of The Great Basin Native Plant Selection and Increase Project (GBNPSIP). In 2000 this project was initiated as a joint effort between the Bureau of Land Management, Forest Service Research, and the Utah Division of Wildlife Resources in an effort to make native seed more available and less expensive for landscape scale restoration projects. To meet restoration goals the GBNPSIP project promotes cultivation of native species to increase seed supplies. This research focuses on overcoming seed dormancy issues that have hindered cultivation through scarification and evaluating germination, establishment, and seed production in a cultural setting of four lupine species : hairy big leaf lupine, (Lupinus prunophilus M.E. Jones [Fabaceae]) ; silky lupine, (L. sericeus Pursh) ; silvery lupine, (L. argenteus Pursh) ; and longspur lupine, (L. arbustus Dougl. ex Lind) five scarification treatments were evaluated sulphuric acid and mechanical treatments significantly improved germination on three of the four species tested. All other treatments were unpredictable and not significant. No treatments significantly improved germination of L. arbustus and three of the five treatments significantly decreased seed germination from the control. Results demonstrate that scarification method, and exposure interval, differ in effectively increasing % germination among species. Germination, establishment, and seed production were evaluated using two planting methods for each species. Broadcast plots (covered) were covered with N-Sulate fabric™ and 5 cm (2 in) of sawdust. Control plots (uncovered) were drilled and left untreated. Germination was significantly improved for all four lupine species under treatment conditions. Lupinus prunophilus and L. sericeus exhibited the greatest improvement in germination when covered. Germination of L. argenteus and L. arbustus were also significantly improved (p<0.0001 and p=0.004, respectively) by the covered treatment. Higher germination in the covered treatment was mirrored in establishment for every species except L. arbustus. There is an advantage of using the covered treatment, but low yields make cultivation unprofitable.

Mots clés : lupine ; Great Basin ; native forb cultivation ; legume scarification

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