Ecology of the microbiotic crust of the antelope-brush (Purshia tridentata) shrub steppe of the South Okanagan, British Columbia
Notice bibliographique
Résumé
This thesis examines two aspects of the microbiotic crust in the antelope-brush (Purshia tridentata (Pursh) D.C.) shrub steppe of the South Okanagan, British Columbia: (1) relationships between the extent, distribution, and composition of the microbiotic crust, soil texture, and primary grazer (wildlife versus livestock), and; (2) effect of the microbiotic crust on soil moisture content and loss. The floral characteristics of the microbiotic crust of five antelope-brush sites are summarised in Chapter I. Differences in species richness and extent, lifeform composition, and quality of the microbiotic crust are described. Preliminary studies identified differences in the floral characteristics of the antelope-brush sites and discussed these differences in relation to soil texture and type of primary grazer. No conclusive relationships between microbiotic crust species numbers, lifeform composition, crust extent, or moss thickness were identified. It was concluded that microbiotic crust colonisation was influenced by soil surface stability and stability may be affected by physical disturbance, such as livestock grazing, or by the mechanical composition and degree of aggregation of the soil. Two of the sites examined were the focus of the soil moisture study presented in Chapter II. The study addressed three questions: 1. Does the microbiotic crust influence soil water content and loss on the antelope-brush sites? 2. Does the soil moisture effect differ with microbiotic crust species? 3. Is the role of the microbiotic crust on soil water more important than influences from other ecosystem components? Soil moisture content was uniformly sampled after two rain events and two factors (shrub and microbiotic crust) were tested in a 2 x 2 factorial design. Shrub cover was included in the experimental design to account for the possible effects of shading and hydraulic lift. Data were analysed with the general linear model and both analysis of variance (ANOVA) and repeated measures multivariate analysis of variance (repeated measures MANOVA) were used. The study determined plots with microbiotic crust at the sample point (crusted plots) reduced infiltration initially, but soils beneath a crust retained the moisture for longer periods than areas sampled in bare soil (non-crusted plots). Shrub cover had little relevance to surface soil moisture conditions other than its effect on microbiotic crust characteristics. Soils beneath lichen crusts received more precipitation and soils beneath moss had better retention of soil water. The water retention ability of soils beneath moss increased with moss thickness. The effect of surrounding plot conditions varied, but generally the conditions at the sample point were paramount. If the sample point was covered by a microbiotic crust (crusted plots), the positive effect on soil moisture was enhanced by surrounding crust characteristics. However, if the sample point was bare (non-crusted plots) the ability of the surrounding microbiotic crust to moderate soil moisture varied. Vascular plant and litter cover moderated moisture conditions in bare soil, but were not as effective as the microbiotic crust.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,002 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».