Soutenance mémoire
Aménagement forestier écosystémique
L’HABITAT ET LE CLIMAT DÉFINISSENT LES RÉPARTITIONS DU PÉKAN ET DE LA MARTRE
Résumé
Depuis le milieu des années 1900, les populations de pékans (Pekania pennanti) ont augmenté dans plusieurs régions de l’est de l’Amérique du Nord, en particulier dans la partie nord de l’aire de répartition de l’espèce. Les changements dans la répartition des pékans ont entraîné un chevauchement croissant avec la martre d’Amérique (Martes americana), dont les populations pourraient être en déclin. Leurs interactions se produisent notamment dans les habitats modifiés par des perturbations naturelles et anthropiques. L’objectif de notre étude était de déterminer les effets respectifs des changements d’habitat et des conditions climatiques sur les populations de pékan et de martre au Québec en se basant sur les savoirs locaux des piégeurs. Les rendements annuels des captures de pékans et de martres (nombre de fourrures vendues 1 100 km2) ont été analysés entre les saisons de piégeage 1984-1985 et 2014-2015. Les pékans bénéficiaient principalement de l’abondance accrue de forêts mixtes de plus de 12 rn de haut, résultant de plusieurs décennies d’exploitation forestière. La récolte de pékan diminuaient par contre avec l’augmentation des pluies froides au printemps, pendant la période d’élevage des jeunes dont la survie pourrait être affectée. La récolte de martre diminue quant à elle après des hivers pluvieux où la pluie crée une croute à la surface de la neige qui réduit l’accès au couvert sous-nival. Le déclin des rendements de martre coïncidait avec une augmentation des rendements de pékans, suggérant une possible compétition interspécifique.
Abstract
Since the mid-1900s, fisher populations (Pekania pennanti) have increased in several easternjurisdictions of North America, particularly in the northern part of the species range. Changes in fisher distribution have led to increased overlap with the southern portion of the range of American marten (Martes americana), whose populations may be locally declining. This overlap occurs particularly in habitats undergoing natural and anthropogenic modification. The objective of our study was to determine the respective effects of habitat changes and climatic conditions on fisher and marten populations in Quebec based on trapper knowledge. Annual fisher and marten harvest (number of
pelts sold/100 km2) were analyzed between the 1984-1985 and 2014-2015 trapping seasons using linear mixed models. Fishers benefitted mainly from the increased abundance of mixed forests > 12 rn tall, resulting from decades of forest harvesting.
Fisher harvest decreased with increasing spring rains, which can affect survival during the period of young rearing. Marten harvest decreased with increasing winter rains which lower thermoregulation capacity, and hamper movements by creating an ice ernst on the snowpack, reducing access to sub-nivean areas. Decline in marten harvest during the 30-year study period coincided with an increase in fisher harvest, suggesting possible interspecific competition.
Introduction
Unregulated harvest and habitat Joss have led to significant declines in populations of severa! forest carnivores in North America (Tapper and Reynolds, 1996; Krohn, 2012).
Fisher (Pekania pennanti) and American marten (Martes americana) are 2 North American mustelids whose populations have drastically decreased due to overexploitation for fur and Joss of habitat due to timber harvesting (Powell et al., 2003; Williams et al., 2007). After a decline during the mid-19’h century, fisher populations have rebounded since the mid-20’h century in the eastern portion of the species range, particularly in the northeastern United States, and in the Canadian provinces of Ontario and Quebec (Bowman et al., 2006; Lancaster et al., 2008; Krohn, 2012; Lewis et al., 2012; LaPoint et al., 2015). Fisher recovery is due in part to reintroduction efforts and natural recolonization (Carr et al., 2007b; Stewart et al., 2017), but it is also associated with habitat modification, as weil as beneficiai effects from climate change (Lancaster et al., 2008). In sorne cases, fisher re-establishment success could result in marten decline, due to interspecific competition (Krohn et al., 1997; Fisher et al., 2013;Manlick et al., 2017). Because of its larger size, fisher is a dominant competitor of marten (Krohn et al., 1997). Interference competition from fishers could have indeed forced martens to le ave shared terri tories (Tannerfeldt et al., 2002). However, marten populations appear to be recovering in severa! parts of eastern North America shared with fisher (Aylward et al., 2018), but not in Quebec. Fisher harvest in Quebec is generally increasing, while that of martens is decreasing (Poulin et al., 2006; Suffice et al., 2017; Lavoie et al., 2019). According to Poulin et al. (2006), increased fisher harvesting in Quebec is more strongly associated with population increases than with increased trapping pressure.
Anthropogenic disturbance and climatic conditions can upset established equilibria and induce changes in habitat use by species (Graham and Grimm, 1990; Lodge, 1993).
North American forests have been greatly affected by human activities over recent decades (agricultural intensification, urbanization and forest Jogging) (Reif, 2013;Bridger et al., 2017). Forest Jogging differs from natural disturbances in terms of frequency, intensity and spatial extent. It has resulted in younger, more fragmented forests with different tree species composition (Schulte et al., 2007; Boucher et al.,2014; Grondin et al., 2018). This in turn increased the number of wildlife species requiring earl y successional habitat but reduced the number of species requiring mature contiguous forest (Drapeau et al., 2000; Nitscke, 2008; Plante et al., 2018). Such modifications in the structure and composition of forest landscapes have a direct effect on habitat availability for mustelids (Buskirk, 1992; Payer and Harrison, 2005; Spencer et al., 2015).
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Table des matières
AVANT-PROPOS
LISTE DES FIGURES
LISTE DES TABLEAUX
LISTE DES ABRÉVIATIONS, DES SIGLES ET DES ACRONYMES
LISTE DES SYMBOLES ET DES UNITÉS
RÉSUMÉ
ABSTRACT
CHAPITRE I INTRODUCTION
1.1 Le pékan et la martre d’Amérique
1.1.1 Phylogénie et morphologie comparées
1.1.2 Domaine vital
1.1.3 Relations interspécifiques
1.1.4 Influence des conditions hivernales
1.1.5 Habitat des mustélidés forestiers
1.1.6 Enjeux de l’aménagement forestier pour les mustélidés
1.2 Exploitation de la forêt tempérée feuillue au Québec
1. 2.1 La forêt tempérée feuillue
1.2.2 Aménagement forestier écosystémique
1.3 Problématique de la thèse
1.3.1 Accès à l’information
1.3.2 Co-construction des savoirs
1.4 Objectifs de la thèse
CHAPITRE II MORE FISHERS AND FEWER MARTENS DUE TO CUMULATIVE EFFECTS OF FOREST MANAGEMENT AND CLIMATE CHANGE AS EVIDENCED FROM LOCAL KNOWLEDGE
2.1 Résumé
2. 2 Abstract
2.3 Introduction
2.4 Methods
2.4.1 Study are a
2.4.2 Recruitment of participants
2.4.3 Data collection and analysis
2.4.4 Ethical considerations
2.5 Results
2. 5.1 Predator-prey relationships
2.5.2 Evolution of captures
2.5.3 Habitat
2.5.4 Forest management
2. 5. 5 Winter conditions
2.6 Discussion
2. 7 Conclusion
2. 8 Declarations 2. 8.1 Ethics approval and consent to participate
2. 8. 2 Funding
2. 8. 3 Author contributions
2. 8.4 Acknowledgements
2.8.5 Author information (optional)
CHAPITRE III HABITAT AND CLIMATE SHAPE FISHER AND MARTEN
3.1 Résumé
3.2 Abstract
3.3 Introduction
3.4 Study are a
3.5 Methods
3. 5.1 Pelt sales data
3.5.2 Habitat data
3.5.3 Climatic data
3. 5.4 Statistical analyses
3.6 Results
3.6.1 Yields
3.6.2 Habitat changes
3.6.3 Changes in rain conditions
3.6.4 Mode! comparisons for fisher
3.6.5 Mode! comparisons for marten
3.7 Discussion
3. 7.1 Habitat changes
3. 7.2 Changes in rain conditions
3. 7.3 Cumulative impacts and relative importance of habitat and climate
change
3. 7.4 Inter-specifie relations: the missing link?
3. 7. 5 Management implications
3.8 Acknowledgements
CHAPITRE IV SITE OCCUPANCY BY AMERICAN MARTEN AND FISHER IN TEMPERA TE DECIDUOUS FOREST
4.1 Résumé
4.2 Abstract
4.3 Introduction
4.4 Methods
4.4.1 Study area
4.4.2 Species detection design
4.4.3 Habitat
4.4.4 Detection covariates
4.4.5 Statistical analyses
4.5 Results
4.5.1 Habitat
4.5.2 Sampling conditions
4.5.3 Detections
4. 5.4 Covariate effects on site occupancy and species detection
4.6 Discussion
4.6.1 Species co-ocurence
4.6.2 Variables influencing occupancy
4.6.3 Variables influencing detection
4. 7 Conclusion
CHAPITRE V CONCLUSION GÉNÉRALE
ANNEXE A
ANNEXE B
ANNEXE C
RÉFÉRENCES
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