THE INTERACTIVE EFFECTS OF MICROTOPOGRAPHY AND HYDROLOGY ON GROUND LAYER VEGETATION AND SOIL GAS FLUX RESPONSES TO A SIMULATED EMERALD ASH BORER INFESTATION IN BLACK ASH WETLANDS
Notice bibliographique
Résumé
Black ash (Fraxinus nigra Marshall) wetlands are at risk of significant ecological and functional changes due to the invasive emerald ash borer (EAB) (Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)), which kills trees in the Fraxinus (ash) genus. Simulated EAB infestations consisting of girdle treatments and ash cut treatments have been implemented in black ash wetlands to study the impacts of black ash canopy dieoff in these systems. Initial findings include ground layer vegetation shifts and impacts to carbon dioxide (CO2) and methane (CH4) release from soils, but these factors and their interactions with microtopography in these systems are not well understood. The objectives of this study were to explore how vegetation and greenhouse gas fluxes (GHGs) are currently responding to simulated EAB treatments in the Ottawa National Forest in the Great Lakes Region of North America six years after initial treatment implementation, and to determine how microtopography affects them as well. Tree seedling counts and diversity were not found to be affected by treatments alone. Microtopography, however, had a larger impact and showed more seedlings and a higher diversity of seedlings growing on hummocks. Seedlings over one year of age were also found in greater numbers and with more diversity on top of hummocks. Herbaceous species have continued their trend of increased cover in treated sites, with higher cover of obligate wetland species and graminoids in treated sites as well. Increased herbaceous cover was found on top of hummocks rather than in hollows. These findings suggest that herbaceous cover is influenced by both treatments and microtopography, while tree regeneration is more influenced by microtopography. The implications of the lack of response between treatments for seedlings is that the increase in water levels at our wetland sites may be buffered by microtopography and our sites could continue to stay forested following an EAB infestation. CO2 and CH4 fluxes showed different responses to treatment and microtopography. CO2 flux was highest in control sites and on top of hummocks, while CH4 was not found to be different between treatments or microtopography. The postulated reasons for these findings are depth to water table and root respiration. For CO2, the lower water levels allowed for more soil to be aerated and decomposed, and there is more root respiration in control sites because of a higher volume of living trees. For CH4, the low water levels created an environment where little CH4 was produced at all. When
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| 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 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 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 source (Gemma direct ou Codex distillé), 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 ».