Diversity of bryophytes in relation to coarse woody debris: does it differ between a post fire and a post clearcut chronosequence?

Transcription

1 Diversity of bryophytes in relation to coarse woody debris: does it differ between a post fire and a post clearcut chronosequence? Myriam Paquette Master student, Biology, UQAT Under the direction of : Yves Bergeron And the codirection of : David Pothier and Nicole Fenton Symposium on deadwood dynamics, Rouyn Noranda May 15 19, 2011

2 Mosses Bryophytes Pleurozium schreberi Sphagnum spp Dicranum polysetum

3 Liverworts Bryophytes Myliataylorii Bazzania trilobata

4 Bryophytes Mosses and liverworts Important role in water and nutrients cycle Biomass Diverse in boreal forest Richness of vascular plants Richness of bryophytes

5 Wildfires vs clearcuts Soil and vegetation disturbance DEAD WOOD Epixylic bryophytes Substrate Microhabitats

6 Objectives and hypotheses Objectives 1. Determine the relationship between bryophytes diversity and dead wood Hypotheses 1. Higher bryophytes richness when CWD volume is high. Decay classes Other types of dead wood are as important as CWD Multiple comparisons (Tukey) Linear regressions Alpha level : 0.05

7 Méthodologie : Aire d étude Plots map with stand ages Post fire chronosequence: 20 stands, 20 to >200 years Post clearcut chronosequence: 18 stands, 20 to 80 years

8 Regional characteristics Long fire cycle High proportion of old growth forests Secondary disturbances

9 Methodology Circular plot (400 m 2 ) Edaphic conditions All coarse woody debris (>9 cm) within 400 m 2 and decay classes Class 1 Class 2 Class 3 Class 4 Class 5 Adapted from Hunter, 1990

10 Methodology 20 sub plots (1 m 2 ) Bryophytes and substrates Percent cover Coarse (CWD) > 9 cm Medium (MWD) Small (SWD) < 2 cm

11 Results

12 Species richness Clearcuts Wildfires (18 stands) (11 stands) Mosses Liverworts Total Mean species number by stand ±SE

13 Species richness Clearcuts Wildfires (18 stands) (11 stands) Mosses 21.3 ±1.2 a 22.5 ±2.0 a Liverworts Total Mean species number by stand ±SE

14 Species richness Clearcuts Wildfires (18 stands) (11 stands) Mosses 21.3 ±1.2 a 22.5 ±2.0 a Liverworts 12.4 ±0.9 a 13.2 ±1.2 ab Total Mean species number by stand ±SE

15 Species richness Clearcuts Wildfires (18 stands) (11 stands) Mosses 21.3 ±1.2 a 22.5 ±2.0 a Liverworts 12.4 ±0.9 a 13.2 ±1.2 ab Total 33.8 ±1.9 a 35.7 ±2.6 a Mean species number by stand ±SE

16 Species richness Clearcuts Wildfires (18 stands) (11 stands) >100 (9 stands) Mosses 21.3 ±1.2 a 22.5 ±2.0 a 21.3 ±2.6 a Liverworts 12.4 ±0.9 a 13.2 ±1.2 ab 17.8 ±1.8 b Total 33.8 ±1.9 a 35.7 ±2.6 a 39.1 ±4.1 a Mean species number by stand ±SE

17 Species richness Clearcuts Wildfires (18 stands) (11 stands) >100 (9 stands) All (20 stands) Mosses 21.3 ±1.2 a 22.5 ±2.0 a 21.3 ±2.6 a 20.8 ±1.7 a Liverworts 12.4 ±0.9 a 13.2 ±1.2 ab 17.8 ±1.8 b 14.4 ±1.3 ab Total 33.8 ±1.9 a 35.7 ±2.6 a 39.1 ±4.1 a 35.2 ±2.7 a Mean species number by stand ±SE

18 Species richness and dead wood : Clearcuts Mosses richness Liverworts richness Species richness CWD volume (m 3 ha 1 ) No statistical difference among age classes Age classes (years)

19 Species richness and dead wood : Clearcuts Mosses richness Liverworts richness Species richness CWD volume (m 3 ha 1 ) No statistical difference among age classes Age classes (years)

20 Species richness and dead wood : Clearcuts Mosses richness Liverworts richness CWD volume (m 3 ha 1 ) Species richness ab a a ab Age classes (years) ab b Time effect? Decay classes effect?

21 Species richness and dead wood : Clearcuts 100 CWD 1 2 CWD 3 4 CWD 5 CWD volume (m 3 ha 1 ) Higher proportion of class 5 More of class 3 4 in older age classes Age classes (years)

22 Species richness and dead wood : Clearcuts Clearcuts : Total species richness and CWD volume by decay classes 60 CWD 1 2 CWD 3 4 CWD 5 Total species richness R² = 0,2102 R² = 0,1758 Species richness is more strongly correlated to class ,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2 Log CWD volume (m 3 ha 1 )

23 Species richness and dead wood : Wildfires Mosses richness Liverworts richness CWD volume (m 3 ha 1 ) Species richness Differences among age classes b ab ab ab a >200 Age classes (years)

24 Species richness and dead wood : Wildfires Mosses richness Liverworts richness Species richness a b abc ac abc 0 CWD volume (m 3 ha 1 ) >200 Age classes (years)

25 Species richness and dead wood : Wildfires Mosses richness Liverworts richness Time effect? Species richness abc b c a ac CWD volume (m 3 ha 1 ) >200 Age classes (years)

26 Species richness and dead wood : Wildfires 80 CWD 1 2 CWD 3 4 CWD 5 More of class 1 2 and 3 4 Less of class 5 CWD volume (m 3 ha 1 ) >200 Age classes (years)

27 Species richness and dead wood : Wildfires Wildfires : Total species richness and CWD volume by decay classes Total species richness CWD 1 2 CWD 3 4 CWD 5 R² = 0,5036 R² = 0,0922 Strong correlation with class ,5 1 1,5 2 2,5 Log CWD volume(m 3 ha 1 )

28 Proportion of richness by types of dead wood Proportion of richness on dead wood 0, , , , , , , , , Clearcuts Wildfires SWD maintain less richness in post fire than post clearcut CWD MWD SWD Stumps Types of dead wood

29 Conclusion Species richness: No difference between disturbances at similar ages Post fire stands over 100 years : liverworts (time) Composition differences? Richness related to CWD : Strongly related to decay class 3 4 (more suitable) All types of dead wood SWD maintain a higher proportion of richness in postclearcut

30 Thank you! Special thanks to Nicole Fenton and Anne Allard Duchêne! Technical helpers Charles Ward Julie Gravel Grenier Martine Lapointe Supervision David Pothier Yves Bergeron Field helpers Jean Philippe Roussy Édith Lachance Julien Pelletier Sébastien Lavoie Jérémie Fuller

31 Forest management Windthrows > partial cut and clearcut with trees retention Salvage logging after windthrow

32 Richness and microhabitats CWD, MWD, SWD, stumps, trunk base, mineral soil and rock Specialist species Abundance bryophytes richness 30 Species richness R² = 0, Number of microhabitats by sub plot

33 M12 Species richness Clearcuts Wildfires (18 stands) (11 stands) >100 (9 stands) All (20 stands) Mosses 56 (21.3±1.2a) 59 (22.5±2.0a) 52 (21.3±2.6a) 69 (20.8±1.7a) Liverworts 33 (12.4±0.9a) 35 (13.2±1.2ab) 34 (17.8±1.8b) 37 (14.4±1.3ab) Total 89 (33.8±1.9a) 94 (35.7±2.6a) 86 (39.1±4.1a) 106 (35.2±2.7a) Species richness (Mean species number by stand ±SE)

34 Diapositive 33 M12 Comparaisons multiples à faire Myriam;

35 CCA of stands Clearcuts Fires 20 to 100 Fires > 100 years

36 CCA of stands Plants Leaves Clearcuts Fires 20 to 100 Fires > 100 years Lichen Variables Pseudo F Age p Origine CWD Age Origine Leaves Lichens Basal area Basal area

37 CCA of species Mosses Plants Leaves Liverworts Lichen CWD Age Origine Basal area

38 CCA of species Mosses Plants Leaves Liverworts Lichen CWD Age Origine Basal area