Nest-site availability, selection and reuse in a cavity-nesting community in forests of interior British Columbia
Notice bibliographique
Résumé
Cavity nesting communities are structured in a complex hierarchy of interdependencies based on the creation of and competition for nest-sites. This structure has been called a nest web. Although cavities are persistent and may be used multiple times, few studies have examined cavity use in relation to availability, or patterns of nest-site reuse. My objectives were to: 1) determine cavity availability and use in continuous and naturally-fragmented forests, and 2) examine nest-site reuse by cavity nesting guilds and species. To examine cavity availability and use, I measured nest-site characteristics in continuous forests and naturally-fragmented aspen (Populus tremuloides) stands in British Columbia. I examined cavity selection at the community, guild and species levels using resource selection indices. Continuous forests had fewer cavities and lower cavity occupancy rates (9-10%) than fragments (35-44%). However, cavity characteristics did not differ between those habitats. Overall, cavity nesters preferred live, unhealthy trees with few holes. Nest-site selection was influenced by tree and habitat attributes, rather than cavity characteristics such as orientation. Low overall occupancy rates suggested that there was a surplus of cavities. To examine nest-site reuse, 193 cavities were monitored between 1995-1999. Eight percent of cavities were destroyed during the study, mainly due to tree blowdown. Cavities were occupied two years in a row, rather than intermittently. Reuse rates were highest for cavities occupied by secondary cavity nesters (48%) and were lowest for those used by weak excavators (17%). Although woodpeckers were the main providers of cavities for secondary cavity nesters in the community, only 28% of cavities used by woodpeckers were occupied the following year. Reuse rates varied considerably among species within all guilds. Deep cavities with large entrances and those in aspen were reused most often, as were those in aspen groves and close to forest edges. I suggest that large-scale attributes such as proximity to foraging habitat are better indicators of nest-site suitability than microhabitat characteristics. Thus cavity-nesting communities should be managed at a larger scale than individual nest trees or cavities. Because cavity abundance does not reflect cavity suitability, counts of holes will not predict the ability of a habitat to sustain cavity-nester populations.
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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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,002 | 0,001 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| 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 ».