Responses of macroinvertebrate community composition to changes in stream abiotic factors after streamside clear-cut logging in the central interior of British Columbia
Notice bibliographique
Résumé
Effects of a clear-cut timber harvest of the riparian zone were studied on 18 stream systems in watersheds influenced by a continental climate regime in the central interior of British Columbia. Streams selected in the Stuart-Takla and Willow-Bowron watersheds were sampled between mid-September and late October 1995. Study streams were classified according to stages of clear-cut harvest in the riparian zone: streams within unharvested reaches, streams without canopy cover (timber harvest less than 5 years old) or streams with a deciduous canopy cover (timber harvest more than 20 years old). Measurements were taken of topographic and habitat attributes, of watersheds and productivity and the benthic macroinvertebrate community. 'Uncut' stream channels had higher gradients and narrower widths than were found in 'old cut' streams suggesting that stream channel dimensions of streams in logged areas may have changed over time. More specifically, 'recent cut' streams had the lowest canopy cover and the highest chlorophyll α biomass. However, in 'old cut' streams with dense canopy cover, chlorophyll α biomass was similar to levels in 'uncut' streams. In addition, although density of benthic macroinvertebrates did not appear to have changed over time, total biomass increased soon after timber harvest. After more than 20 years, biomass measurements of macroinvertebrates were similar to levels found in unharvested streams. Density and biomass of the scraper functional guild, in particular, were lowest in 'recent cut' streams. These streams also had the highest densities of predators and invertebrate parasites and the highest biomass of collector functional guilds and leeches. Higher biomass of the two collector guilds in 'recent cut' streams may have been linked to an increase in the quality of their food source, i.e., FPOM, although this was not measured in this study. Higher biomass of scrapers and collectors found soon after the timber harvest may have attracted resident fish into these streams, and so increased fish parasite biomass. After more than 20 years following timber harvest, biotic and abiotic factors may have returned to levels found prior to timber harvests. Future work is required to determine the factors that influence changes in benthic community composition and instream habitat in stream ecosystems following timber harvest in this region.
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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 | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 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 ».