Relations entre la diversité et la productivité végétale vis-à-vis des caractéristiques structurales et fonctionnelles des érablières du Centre du Québec

Leniere, Alexandre
Philosophiæ doctor (Ph.D.)
Université Laval
Doctorat en biologie

Directeur(trice) de recherche : Houle, Gilles

2007-05

Table des matières

CHAPITRE 1 – Introduction générale
CHAPITRE 2 – Response of herbaceous plant diversity to reduced structural diversity in maple-dominated (Acer saccharum Marsh.) forests managed for sap extraction
CHAPITRE 3 – Short-term understory plant community response to nutrient spatial heterogeneity in the cold-temperate deciduous forest of south-eastern Canada
CHAPITRE 4 – Plant community response to species losses in the understory of cold-temperate deciduous forests in south-eastern Canada.
CHAPITRE 5 – Conclusion générale

Liste des illustrations

Figure 1.1 Répartition des régions forestières du Canada pour la province de Québec (Tirée de Ressources Naturelles Canada – Service canadien des forêts). http://192.75.17.6/OG/OldGrowthPosters/OldGrowthPoster-f.htm
Figure 1.2 Répartition des différents domaines bioclimatiques de l’érablière dans la province du Québec (Extrait de Auger et al. (2004)).
Figure 2.1 Localization of the forest fragments studied in the Bois-Francs region, Québec, Canada. The number of sites at each locality is given in parentheses.
Figure 2.2 Path diagram for the relationships between the mean of the environmental variables, the structural diversity index (H), and herbaceous plant diversity (zherb) at the 30 study sites (Bois-Francs region, Québec, Canada). R²represents the total explained variance and ρ the direct causal covariance (path coefficient). Irrad: irradiance; SOM: soil organic matter; SM: soil moisture.
Figure 2.3 Path diagram for the relationships between the CV of the environmental variables, the structural diversity index (H), and herbaceous plant diversity (z_herb) at the 30 study sites (Bois-Francs region, Québec, Canada). R² represents the total explained variance and ρ the direct causal covariance (path coefficient). Irrad: irradiance; SOM: soil organic matter; SM: soil moisture.
Figure 2.4 Positive relationship between soil pH and herbaceous plant diversity (z_herb) over the 30 study sites, Bois-Francs region, Québec, Canada.
Figure 3.1 Experimental design: (a) control, i.e., no nutrient application (N0); (b) homogeneous nutrient application (N1); (c, d, and e) three increasing scales of nutrient application (N64, N16, and N4).
Figure 3.2 Experimental set up to record plant cover and richness in each 4 m² plot.
Figure 4.1 Experimental set up to record plant cover and diversity in each 4 m²plot.
Figure 4.2 Total richness (Rtot) and functional group richness (RSE: spring-flowering ephemeral species; RSP: spring-flowering persistent species; RSM: summer-flowering species; RFE: fern species; and RTS: seedlings and juveniles of woody species) for each treatment. Different letters indicate significant differences among treatments for each variable (P < 0.05, protected LSD). Mean + SD.
Figure 4.3 Total cover (Ctot) and functional group cover (CSE: spring-flowering ephemeral species; CSP: spring-flowering persistent species; CSM: summer-flowering species; CFE: fern species; and CTS: seedlings and juveniles of woody species) for each treatment. Different letters indicate significant differences among treatments for each variable (P < 0.05, protected LSD). Mean + SD.
Figure 4.4 Total species evenness (Htot) and functional group species evenness (HSE: spring-flowering ephemeral species; HSP: spring-flowering persistent species; HSM: summer-flowering species; HFE: fern species; and HTS: seedlings and juveniles of woody species) for each treatment. Different letters indicate significant differences among treatments for each variable (P < 0.05, protected LSD). Mean + SD.
Figure 4.5 Interactions between the different functional groups for species richness (based on Fig. 4.2 and Table 4.4).
Figure 4.6 Interactions between the different functional groups for species cover (based on Fig. 4.3 and Table 4.4).

Liste des tableaux

Table 2.1 General characteristics, number of species (in parentheses, herbaceous plant species), proportion of herbaceous species (vs. total species number), and parameter and statistics of the species-area curve for the 30 study sites (Bois-Francs region, Québec, Canada).
Table 2.2 Structural characteristics of the 30 study sites (Bois-Francs region, Québec, Canada). Symbols as in Table 2.1.
Table 2.3 Mean value (± SD) and coefficient of variation (CV, in %) of the environmental variables at the 30 study sites (Bois-Francs region, Québec, Canada). Symbols as in Table 2.1. Measures (n = 46) were taken on the diagonal of an 800 m² plot at each site.
Table 2.4 Pearson coefficient of correlation between the variables studied^a (*: P < 0.05; **: P < 0.01; ***: P < 0.001), n = 30 (Bois-Francs region, Québec, Canada).
Table 3.1 List of all vascular plant species recorded (all treatments and all sites combined). Nomenclature follows Marie-Victorin (1995). SE: spring-flowering ephemeral species; SP: spring-flowering persistent species, SM: summer-flowering species; FE: ferns; and TS: seedlings and juveniles of woody species.
Table 3.2 Experimental protocol for the different nutrient addition treatments. No fertiliser was added to the control plots (N0).
Table 3.3 F-values (P-values in parentheses) from the ANOVAs for the effects of site (df = 2), treatment (df = 4), and their interaction (df = 8) on total cover (Ctot), total richness (Rtot), spatial autocorrelation of total richness (SA), total evenness (Htot), functional group evenness (HSE, HSP, HSM, HFE, and HTS), and three environmental factors (soil pH, soil organic matter (SOM), and irradiance). SE: spring-flowering ephemeral species; SP: spring-flowering persistent species, SM: summer-flowering species; FE: ferns; and TS: seedlings and juveniles of woody species. Significant values are in boldface characters.
Table 3.4 Species richness for the three sites combined and for each site according to functional group (SE: spring-flowering ephemeral species; SP: spring-flowering persistent species; SM: summer-flowering species; FE: ferns; TS: seedlings and juveniles of woody species).
Table 3.5 Total cover (Ctot), functional group cover (CSE, CSP, CSM, CFE, and CTS), total richness (Rtot), functional group richness (RSE, RSP, RSM, RFE, and RTS), total evenness (Htot), and functional group evenness (HSE, HSP, HSM, HFE, and HTS) for each treatment. SE: spring-flowering ephemeral species; SP: spring-flowering persistent species; SM: summer-flowering species; FE: ferns; and TS: seedlings and juveniles of woody species. Different letters indicate significant differences among treatments for each variable (protected LSD with P ≤ 0.05). Mean ± SD (n = 9). See Fig. 3.1 and Table 3.2 for details on the nutrient application treatments.
Table 3.6 Mean (± SD; n = 9) of three environmental variables (soil pH, soil organic matter (SOM), and irradiance) as a function of year and treatment. There are no significant differences among treatments for each variable. See Fig. 3.1 and Table 3.2 for details on the nutrient application treatments.
Table 4.1 Functional groups, symbols, and examples of species in the different groups.
Table 4.2 Species richness for the three sites combined and for each site (data from 2005) according to functional group (SE: spring-flowering ephemeral species; SP: spring-flowering persistent species; SM: summer-flowering species; FE: ferns; TS: seedlings and juveniles of woody species; Total: all species combined).
Table 4.3 F-values (in parentheses, P-values) from the ANOVAs for the effects of site (df = 2) and treatment (df = 5 for Rtot, SA, Ctot, Htot, soil ph, soil organic matter content, and irradiance; df = 4 for the other variables) and for their interaction (df = 10 for Rtot, SA, Ctot, Htot, pH, SOM, and irradiance; df = 8 for the other variables) on the variables studied. Rtot: total richness; RSE, RSP, RSM, RFE, RTS: richness of spring-flowering ephemeral species, spring-flowering persistent species, summer-flowering species, ferns, and seedlings and juveniles of woody species, respectively; Ctot: total cover; CSE, CSP, CSM, CFE, and CTS: cover of spring-flowering ephemeral species, spring-flowering persistent species, summer-flowering species, ferns, and seedlings and juveniles of woody species, respectively; Htot: evenness of all species; HSE, HSP, HSM, HFE, and HTS: evenness of spring-flowering ephemeral species, spring-flowering persistent species, summer-flowering species, ferns, and seedlings and juveniles of woody species, respectively. Significant values are in boldface characters.
Table 4.4 Observed and expected¹ total richness (Rtot), total cover (Ctot), and total evenness (Htot) as a function of treatment (LSE: removal of spring-flowering ephemeral species; LSP: removal of spring-flowering persistent species; LSM: removal of summer-flowering species; LFE: removal of ferns; LTS: removal of seedlings and juveniles of woody species). Mean ± SD (n = 9). Different letters indicate significant differences between the observed and expected values for each treatment (P < 0.05; paired t-test).
Table 4.5 Mean (± SD) of the environmental variables as a function of treatment (n = 9). There are no significant differences among treatments (L0: control; LSE: removal of spring-flowering ephemeral species; LSP: removal of spring-flowering persistent species; LSM: removal of summer-flowering species; LFE: removal of ferns; LTS: removal of seedlings and juveniles of woody species), for each variable.


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