Revegetation of riparian tree species along the lower Colorado River is currently a major activity for federal and state agencies. Revegetation methods for Fremont cottonwood (Populus fremontii), Goodding's willow (Salix gooddingii), and coyote willow (S. exigua) have historically consisted of cutting collection and vegetative propagation. If direct seeding could be implemented, large cost-savings could be realized while enhancing restoration results due to increased genetic and structural diversity. The following documents laboratory, greenhouse, and field studies conducted to establish seed storage practices, irrigation techniques, and seeding methods and rates which maximize germination and growth rates of these riparian tree species. Experimental seed storage study results indicated that seed viability was maintained for at least a two-year window by freezing, during which seed can be utilized for direct seeding or seedling production. Greenhouse study results include: (1) seed cleaning resulted in higher tree establishment; (2) adverse soil conditions reduced growth rates; (3) organic fertilizer amendment mitigated negative effects of sandy soil for Fremont cottonwood but not for willow; (4) mixed seeding resulted in cottonwood dominance, indicating that reduced rates or separate seeding of this species might be required to improve success of willow species seeding. Small-scale field study results include the following: (1) Fremont cottonwood establishment averaged 7% of pure live seed rates, whereas willow species establishment was less than 1%; (2) sprinkler irrigation did not affect establishment, and decreased tree growth rates; (3) hydroseeding resulted in higher canopy cover, establishment, and above-ground biomass compared to broadcast seeding for all three species; (4) furrow or border irrigation did not affect Fremont cottonwood or coyote willow establishment, but furrow irrigation resulted in higher Goodding's willow establishment. Volunteer species were abundant, with grasses dominating cover and biomass after one growing season despite application of grass specific herbicide. Saltcedar (Tamarix ramosissima) also established in abundance, but grew slower than Fremont cottonwood during the first growing season. Monitoring after three growing seasons indicated higher growth rates and survival of Fremont cottonwood compared to volunteer species. Larger-scale seeding studies are required to refine establishment rates and determine the cost-effectiveness of direct seeding for large-scale Salicaceae species revegetation.

No description available.

In Canada, willow (Salix spp.) short rotation intensive cultures (SRIC) have been established to investigate their potential to produce biomass for bioenergy. Since root-associated fungal communities are involved in plant nutrition and disease susceptibility, it is relevant to understand their interactions with willows and their role on the sustainability of SRIC. In this project traditional methods together with molecular techniques were used to: i) assess the diversity of fungal communities in roots of willows and their relationship with major characteristics of SRIC ii) evaluate the effects on plant development of potentially beneficial and pathogenic fungi, and iii) identify arbuscular mycorrhizal fungal (AMF) species and their interaction with promising Salix clones. Potentially pathogenic fungi were more dominant in diseased and recently planted cuttings than in healthy older ones. This suggested the occurrence of a positive shift prompted by the establishment of the cuttings on the site. Gibberella/Fusarium sp. and Neonectria sp. were the most dominant taxa particularly in diseased plants. Under greenhouse conditions the inoculation with potentially beneficial and potentially pathogenic fungi induced significant differences in root biomass but not in overall aerial biomass production. PCR-denaturing gradient gel electrophoresis was successfully standardized and used to identify arbuscular mycorrhizal fungal species associated with different clones. The results indicated a degree of specificity between AMF species and plant genotype. Root-associated fungal communities appear to be useful to monitor the impacts of SRIC on soil ecology and their study may enlighten effective ways to increase the productivity of these biomass systems.

Given that morphological identification of willow is difficult, willow lines being investigated for their suitability for use as short rotation crops for biomass production in Saskatchewan were investigated with various molecular techniques as possible tools for DNA fingerprinting. Flow cytometry was used to assess variation in nuclear DNA content and thus ploidy level of the lines of the five species (<i>Salix purpurea, Salix eriocephala, Salix sachalinensis, and Salix dasyclados</i>) and three hybrids (<i>S. purpurea x S. miyabeana, S. sachalinensis x S. miyabeana, S. viminalis x S. miyabeana</i>). The DNA content varied between 1.14 and 3.00pg. Ploidy levels of the species varied from triploid to hexaploid while all hybrids were tetraploid. RAPD and ISSR marker systems were used to assess genetic and taxonomic relationships among all willow lines. Of 90 RAPD primers tested, 60 were selected and 99 polymorphic bands scored. Of 35 ISSR primers tested, 19 were selected and 35 polymorphic bands scored. Both RAPD and ISSR dendrograms clustered together lines belonging to the same species and same hybrid combination. A combination of strong and reproducible RAPD and ISSR bands was used to develop identification keys for lines belonging to the same species.<p> The ribosomal RNA gene region, including the entire 5.8S RNA gene and the internal transcribed spacers (ITS1 and ITS2) was amplified and sequenced to assess sequence homology between the five species. The total length of the amplified region was 601bp, with the ITS1, 5.8 S and ITS2 being 223, 163, and 215bp respectively. Intra- and inter-species SNPs were observed, 6 within ITS1, and 3 within ITS2. No polymorphisms were found in the 5.8S gene. The low rate of variation within the sequenced ITS fragment between species supports the monophyly of the five species involved in this study, and confirms their belonging to the subgenus Caprisalix. SCAR primers were designed from species-specific polymorphic nucleotides and applied to the willow collection to test their use for species identification. A species identification key based on SNPs is proposed.

Given that morphological identification of willow is difficult, willow lines being investigated for their suitability for use as short rotation crops for biomass production in Saskatchewan were investigated with various molecular techniques as possible tools for DNA fingerprinting. Flow cytometry was used to assess variation in nuclear DNA content and thus ploidy level of the lines of the five species (<i>Salix purpurea, Salix eriocephala, Salix sachalinensis, and Salix dasyclados</i>) and three hybrids (<i>S. purpurea x S. miyabeana, S. sachalinensis x S. miyabeana, S. viminalis x S. miyabeana</i>). The DNA content varied between 1.14 and 3.00pg. Ploidy levels of the species varied from triploid to hexaploid while all hybrids were tetraploid. RAPD and ISSR marker systems were used to assess genetic and taxonomic relationships among all willow lines. Of 90 RAPD primers tested, 60 were selected and 99 polymorphic bands scored. Of 35 ISSR primers tested, 19 were selected and 35 polymorphic bands scored. Both RAPD and ISSR dendrograms clustered together lines belonging to the same species and same hybrid combination. A combination of strong and reproducible RAPD and ISSR bands was used to develop identification keys for lines belonging to the same species.<p> The ribosomal RNA gene region, including the entire 5.8S RNA gene and the internal transcribed spacers (ITS1 and ITS2) was amplified and sequenced to assess sequence homology between the five species. The total length of the amplified region was 601bp, with the ITS1, 5.8 S and ITS2 being 223, 163, and 215bp respectively. Intra- and inter-species SNPs were observed, 6 within ITS1, and 3 within ITS2. No polymorphisms were found in the 5.8S gene. The low rate of variation within the sequenced ITS fragment between species supports the monophyly of the five species involved in this study, and confirms their belonging to the subgenus Caprisalix. SCAR primers were designed from species-specific polymorphic nucleotides and applied to the willow collection to test their use for species identification. A species identification key based on SNPs is proposed.

In Canada, willow (Salix spp.) short rotation intensive cultures (SRIC) have been established to investigate their potential to produce biomass for bioenergy. Since root-associated fungal communities are involved in plant nutrition and disease susceptibility, it is relevant to understand their interactions with willows and their role on the sustainability of SRIC. In this project traditional methods together with molecular techniques were used to: i) assess the diversity of fungal communities in roots of willows and their relationship with major characteristics of SRIC ii) evaluate the effects on plant development of potentially beneficial and pathogenic fungi, and iii) identify arbuscular mycorrhizal fungal (AMF) species and their interaction with promising Salix clones. Potentially pathogenic fungi were more dominant in diseased and recently planted cuttings than in healthy older ones. This suggested the occurrence of a positive shift prompted by the establishment of the cuttings on the site. Gibberella/Fusarium sp. and Neonectria sp. were the most dominant taxa particularly in diseased plants. Under greenhouse conditions the inoculation with potentially beneficial and potentially pathogenic fungi induced significant differences in root biomass but not in overall aerial biomass production. PCR-denaturing gradient gel electrophoresis was successfully standardized and used to identify arbuscular mycorrhizal fungal species associated with different clones. The results indicated a degree of specificity between AMF species and plant genotype. Root-associated fungal communities appear to be useful to monitor the impacts of SRIC on soil ecology and their study may enlighten effective ways to increase the productivity of these biomass systems.

The distribution of Lahontan cutthroat trout Oncorhynchus clarki henshawi was assessed in a high-desert stream in southeastern Oregon where beaver Castor canadensis are abundant. Longitudinal patterns of beaver ponds, habitat, temperature, and Lahontan cutthroat trout age group distribution were identified throughout Willow Creek. Three distinct stream segments were classified based on geomorphological characteristics. Four beaver-pond and four free-flowing sample sections were randomly located in each of the three stream segments. Beavers substantially altered the physical habitat of Willow Creek increasing the depth and width of available habitat. In contrast, there was no measurable effect on water temperature. The total number of Lahontan cutthroat trout per meter was significantly higher in beaver ponds than free-flowing sections. Although density (fish/m��) showed no statistically significant (P<0.05) increase, values in beaver ponds were two-fold those of free-flowing sections. Age-1 and young-of-the-year trout were absent or in very low numbers in lower Willow Creek because of elevated temperatures, but high numbers of age-2 and 3 (adults) Lahontan cutthroat trout were found in beaver ponds where water temperatures reached lethal levels (>24��C). Apparently survival is greater in beaver ponds than free-flowing sections as temperatures approach lethal limits. / Graduation date: 2003

Thesis (D. Min.)--McCormick Theological Seminary, 2004. / Includes bibliographical references (leaves 41-42).

Syftet med den här studien var att undersöka om revirstorleken påverkar den reproduktiva framgången hos lövsångarhanar. Datan samlades in i södra Sverige mellan 1984 och 1988 och består av etableringsdatum av revir, revirstorlek, antal partners (en eller ingen), datum för parning, antal ägg i kullen och antal flygga ungar. Det fanns inget samband mellan revirets storlek och de olika variablerna. Inte heller fanns det något samband mellan revirstorlek och hanens ålder när samma individ följdes över tid. Det fanns inget samband mellan revirstorlek och huruvida hanarna parades eller inte. Sammanfattningsvis påverkar inte revirstorleken hanens reproduktiva framgång. Istället finns det andra faktorer som troligtvis påverkar, som revirets kvalitet (t.ex. föda och predatorskydd), hanens ankomsttid, hanens sångrepertoar, hanens ålder samt föräldrarnas kondition. / The aim of this study was to examine if territory size of Willow Warbler males affects reproductive success. The data were collected in the south of Sweden between 1984 and 1988 and consist of date of establishing territory, territory size, number of partners (one or none), date of pairing, number of laid eggs and number of fledglings. There were no relationships between territory size and the different variables, nor was there a relationship between age of the male and territory size when following the same individual over time. There was also no relationship between territory size and whether or not the males reproduced or not. In summary, I could find no relationship between territory size and male reproductive success. Instead, other factors are likely to affect reproductive success, such as territory quality (i.e., abundance of food, safety from predation), male time of arrival, male song repertoire, male age and the body condition of the male and his partner.

I evaluated the spatial and temporal patterns of the avian communities in the Colorado River delta, Mexico, and their relationship with vegetation type and surface water. I also developed plausible conservation and restoration guidelines for riparian areas and native birds in the region. The study included monthly point counts at 30 transects (240 points) from May 2002 to July 2003, breeding counts at 175 sites (3 times per year) during 2002 and 2003, and habitat measurements at the survey points.The most common species were Mourning Doves, Red-winged Blackbirds, and Brown-headed Cowbirds, but another 64 species were commonly found, including Verdins, Song Sparrows, Yellow-breasted Chats and Abert's Towhees. Surface water was the most important habitat feature related to avian richness and density regardless of vegetation type or land cover (P &lt; 0.005). During summer, species richness was explained by variations in water and the cover of cottonwoods (r2 = 0.56, P &lt; 0.001), and the variation in bird densities was explained by variations in water and the cover of willows (r2 = 0.35, P = 0.003).When comparing native versus saltcedar dominated sites, both with the presence (wet) or absence (dry) of surface water, the diversity of birds was more influenced by the presence of water than by vegetation type. Bird abundance was more influenced by vegetation type, but water also had an important effect, as wet sites had higher bird abundance than dry sites with the same vegetation type, and saltcedar wet areas had similar avian abundance to native dry sites. On all cases, the presence of water was an important factor determining the ecological value, in terms of avian richness, abundance, and diversity, of both native riparian and saltcedar areas. Saltcedar areas with surface water had avian characteristics similar to native riparian sites.The dedication of instream flows and pulse floods, the maintenance of vegetation cover and structural diversity, and an increase of older riparian stands will secure the viability of existing bird populations and will increase the probability of recovery of the species that are still extirpated from the floodplain of the Colorado River in Mexico.