Effects of selection cutting on the abundance and fertility of indicator lichens <i>Lobaria pulmonaria</i> and <i>Lobaria quercizans</i>
Notice bibliographique
Résumé
Summary Although selection cutting is probably less harmful to forest ecosystems than clear cutting, its effects on biodiversity remain largely unexplored. We investigated the previously unstudied effects of selection cutting on the abundance and fertility of two dominating species of epiphytic lichens, Lobaria pulmonaria and Lobaria quercizans , in a northern hardwood forest of New Brunswick, Canada. Twenty‐eight forest stands were selected representing two contrasting silvicultural treatments: fairly recent selection cuts (5–9 years) and ‘uncut’ stands that had been subjected to low‐intensity single‐tree cutting at least 35 years ago. Within each stand, we quantified the abundance and fertility of lichens on 36 trees together with selected forest stand variables. Although both species had survived harvesting, the abundance of L. quercizans and L. pulmonaria was four and five times higher, respectively, in uncut stands than in selection cuts. The most important predictive factors for lichen abundance at the stand level were total basal area and canopy closure, which were much lower in selection cuts. Furthermore, the abundance of both species at the tree level was significantly correlated with tree size. Most interestingly, fertile L. quercizans and L. pulmonaria were, respectively, five and 26 times more frequent in uncut stands. In addition, for L. pulmonaria the fertility frequency was only 3% in selection cuts, compared with 37% in uncut stands. The fertility of both lichen species was strongly correlated with their abundance at the tree level. Synthesis and applications. Our results indicate that selection cutting has a strong impact on the abundance and fertility of these two Lobaria species, and that studies ignoring fertility may underestimate the negative effects of forestry on lichens. To reduce the negative effects we have three recommendations. (i) Large trees from old seral stages should be retained during selection cuts. (ii) The cutting cycle should be extended and the basal area removed should be reduced. These actions would improve the microclimate, increase the amount of suitable habitat and prolong the time window for lichen colonization in selection cuts. (iii) Some mature deciduous forest stands should be protected at the regional scale. This would promote the long‐term persistence of large, sexually reproductive lichen populations and concurrently benefit all species tightly linked with mature hardwood forests.
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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) | 0,000 | 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 ».