Effects of water-level management on the abundance and habitat use of waterfowl and marsh birds in the Saskatchewan River Delta, Manitoba, Canada
Notice bibliographique
Résumé
Waterbird habitat in the Saskatchewan River Delta (SRD) has been altered by numerous upstream and downstream anthropogenic developments. Wetland water-level management has been used in an attempt to mitigate these changes, but the effects on the local waterbird community are unknown. Using an experimental approach, I examined the effects of wetland water-level management on waterfowl and marsh birds in the SRD. In 2007, three wetland basins in the Summerberry Marsh Complex, Manitoba were partially drawn down and paired with three additional wetlands managed with high water levels. In 2008-09, I surveyed waterfowl within the study wetlands during different life stages using point counts and aerial surveys. Abundances of breeding marsh birds, including American Bitterns, Least Bitterns, Soras, Virginia Rails, Yellow Rails, American Coots, and Pied-billed Grebes were estimated using call-response surveys. Generalized linear and generalized linear mixed models were used to determine relationships between relative bird abundances and the physical characteristics, vegetation characteristics, and forage fish and invertebrate abundances within the wetlands. Dabbler species of waterfowl preferred the partial drawdown wetlands during nearly all life stages, except brooding. Diver species preferred the non-drawdown wetlands, but only during the spring-breeding and fall-staging periods. Invertebrate abundance affected wetland use by dabbler and diver species, particularly during the spring-breeding and brooding periods. Subsequently, wetlands with high forage fish abundances were avoided. In the fall, dabbler densities on the partial drawdown wetlands increased from an average of 0.4 birds per hectare to 1.5 birds per hectare. This influx was likely due to the accessibility and availability of submerged aquatic vegetation. The partial water-level drawdowns did not benefit any species of marsh birds examined. American Bitterns, American Coots, and Pied-billed Grebes chose the deeper, non-drawdown wetlands, due to high abundances of forage fish. Vegetation interspersion, particularly that offered by Schoenoplectus, was preferred by these species. Soras and Virginia Rails were not affected by water depth or vegetation characteristics, but were positively correlated to invertebrate abundances. Subsequently, the Sora avoided wetlands with high forage fish abundance. The conditions created by the partial water-level drawdowns did not meet the requirements of all species present in the SRD. Therefore, future wetland management should focus on providing a wide range of water depths within wetland complexes to accommodate the requirements of different avian species.
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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 | 0,000 | 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) | 0,000 | 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 ».