Black spruce (<i>Picea mariana</i>) colonization of subarctic snowpatches in response to warmer climate
Notice bibliographique
Résumé
Abstract Snowpatches are disjunct arctic ecosystems scattered across the subarctic, particularly on wind‐protected lee slopes, where a thick snow cover accumulates during the winter. These snow‐rich treeless ecosystems are affected by delayed snowmelt, causing shorter growing seasons. Snow‐tolerant plants occupy the centre of subarctic snowpatches, whereas black spruce trees grow at the margins. Snowpatches have shown sporadic expansion and shrinkage phases from tree establishment and mortality linked to climatic trends. Field surveys in the subarctic of eastern Canada are showing an afforestation process occurring in snowpatches. The origin and nature of this afforestation were investigated based on the hypothesis that tree colonization and growth were closely associated with recent changes in climate. Snowpatches were categorized into three types based on border trees: forested, semi‐forested and tundra‐like. In eight randomly selected snowpatches of each type, snowpatch borders and areas covered by deciduous shrubs or trees were mapped and chionophilous plants and frost‐associated soil disturbances were recorded. Radial (tree‐ring) and vertical growth were measured on stems to evaluate the impact of climate and local factors on snowpatch black spruce populations. Two waves of spruce colonization occurred in all forested and semi‐forested snowpatches in the 1960s and in the 1980s to present. Spruce establishment was more frequent and abundant in recent years, near the forest margins and on moss and barren seedbeds. Expanding shrub (dwarf birch) cover inhibited spruce seedling establishment. Tree establishment and growth were positively correlated with growing season temperature and negatively correlated with annual maximum snow depth. More recently established spruce seedlings exhibited faster vertical growth than those established in the 20th century. Synthesis . Due to warmer conditions and earlier snowmelt in eastern Canada, black spruce trees and dwarf birch shrubs are racing through subarctic snowpatches. This afforestation could change biodiversity in the subarctic and affect watershed dynamics through a change in snowmelt pattern. Subarctic snowpatches are climate‐sensitive ecosystems of the forest–tundra landscape, forming ideal biotopes for snow‐tolerant, arctic–alpine species. Further tree encroachment in snowpatches in this century is potentially a threat to plant diversity, especially chionophilous species that have no corridors to migrate towards arctic ecosystems.
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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 | 0,001 | 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) | 0,005 | 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 ».