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Accueil du site → Doctorat → États-Unis → 2005 → Improving seedling establishment on the saline playa at Owens Lake, California through soil amendment, improved seed quality, and increased seed entrapment

UNIVERSITY OF CALIFORNIA, DAVIS (2005)

Improving seedling establishment on the saline playa at Owens Lake, California through soil amendment, improved seed quality, and increased seed entrapment

Breen, Amanda Nicole

Improving seedling establishment on the saline playa at Owens Lake, California through soil amendment, improved seed quality, and increased seed entrapment

Auteur : Breen, Amanda Nicole

Grade : Doctor of Philosophy (PhD) 2005

Université de soutenance : UNIVERSITY OF CALIFORNIA, DAVIS

Résumé
Generation of fine particulate dust air pollution from aridland lakebeds creates severe air pollution problems that must be reduced or eliminated. Diversion of water to Los Angeles from the Owens River in the early part of the 20th century resulted in the desiccation of Owens Lake, California (36° 30’ N, 118°W ; 1083 m). The establishment of native vegetation is one method proposed to stabilize shifting soil and minimize air pollution there. Native species are pre-adapted to the severe environmental conditions present at Owens Lake, including high salinity, high boron, heat, abrasion and burial by moving sand, and limited water and nutrient availability. Successful colonization, though, hinges on the ability of seedlings to survive and grow in this stressful environment. Atriplexparryi and Sarcobatus vermiculatus have naturally colonized exposed shoreline and were therefore chosen for study and potential use in desert playa dust mitigation. There are many factors that influence the ability of a species to establish in an area. These studies focus on three factors : improving seed production and quality, increasing the number of seeds remaining in the area after seed dispersal, and improving seedling growth after germination. First, increased nutrient availability increased fecundity of adult plants. Seed number per branch, seed size, and viability increased with additions of water and fertilizer. Larger seeds, however, were not more likely to establishthan smaller seeds. In fact, the environment at which a seed arrives is more important than seed size or the maternal environment with regards to successful seedling establishment. Secondly, ample seed is dispersed onto the playa and was trapped best by coarse gravel or wood barriers. Thirdly, fertilization alone or in combination with soil amendments increased seedling biomass, seedling survival after a simulated browsing event, and increased flowering, whereas soil amendments alone did not. Taken together these results demonstrate the potential ability for native halophyte shrub seedlings to establish naturally, given adequate nutrient and water addition to seed-producing adult shrubs and safe site availability for seed entrapment and establishment. An approach that includes improved seed production and quality from established adult shrubs may be a viable way to sustainably meet dust mitigation requirements in this severe environment

Mots clés : BIOLOGY, BOTANY ; BIOLOGY, ECOLOGY ; BIOLOGY, PLANT PHYSIOLOGY

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Page publiée le 17 septembre 2006, mise à jour le 18 janvier 2017