The Norwegian monitoring program for sub-alpine birch-forests

Transcription

1 The Norwegian monitoring program for sub-alpine birch-forests Effects of air pollution and climate change on ground vegetation Vegar Bakkestuen & Per Arild Aarrestad

2 Norwegian sub-alpine birch-forests the forest line Content:: Presentation of the monitoring program Climatic and air pollution scenario in Norway Main drivers for vegetation change Monitoring approach Results Discussion

3 The Norwegian terrestrial monitoring program - TOV Time scale (6) areas from south to north Effects of air pollution and climate change on sub-alpine birch forests TOV includes monitoring of: Ground vegetation Birds Rodents Epiphytic lichens Moths Radioactive deposition

4 Deviation from yearly mean temperature ( C) Varmer climate in Norway Predicted 2,5 2,0 1,5 1,0 0,5 0,0-0,5-1,0-1,5-2, TOV-period

5 Yearly precipitation in % of the normal Wetter climate in Norway Predicted TOV-period

6 Small decrease in total N-deposition Lund et al. (2013)

7 mg N/m 2 /year Total nitrogen deposition in TOV-areas Total nitrogen deposition Lund Møsvatn Gutulia Åmotsdalen Børgefjell Dividalen CL of N South North Climate periods

8 Strong decrease in S-deposition Lund et al. (2013)

9 mg S/m 2 *year Change in S-deposition in TOV-areas Decreased deposition Total S deposition Lund Dividalen Aas et al. (2012)

10 Ground vegetation Dwarf shrubs Herbs Graminoids Bryophytes Lichens

11 Main drivers for vegetation change Climate Temperature Precipitation Soil Nutrients ph Air pollution N-deposition S-deposition Ground vegetation Dwarf shrubs Herbs Graminoids Bryophytes Lichens Grazing Domestic animals Deers Rodents Moths Natural forest development

12 Monitoring approach - ground vegetation 10 macro-plots (5 x 10 m), covering the main environmental gradients, with 5 permanently marked 1m 2 vegetation plots, totally 50 permanet vegetation plots Species abundances measured by both subplot frequency (16 subplots) and percentage cover Soil characteristics sampled and analysed for soil ph, soil extractable cations, S and N Analysed each five years Ca recordings of species occurrence from 1993 to 2015 Bakkestuen et al. (2010)

13 Analyses of permanent plots in Børgefjell National Park Year 2005 Year 2015

14 % cover Results - all TOV localities: Changes of herbs from Increased cover of herbs 60 Average cover of herbs Lund Møsvatn Gutulia Åmotsdal Børgefjell Dividal Analyse period

15 % cover Changes of grasses from Increased cover of graminoids 30 Average cover of graminoids Lund Møsvatn Gutulia 10 5 Åmotsdal Børgefjell Dividal Avenella flexuosa Analyse period

16 % cover Changes of liverworts from Decreased cover of liverworts Liverworts Analyse period Lund Møsvatn Gutulia Åmotsdal Børgefjell Dividal Bazzania trilobata

17 Frequancy abundance Changes of lichens from Decreased cover of lichens 14 Lichens Møsvatn 6 Gutulia Åmotsdal 4 Børgefjell Dividal Cladonia stellaris Analyse period

18 ph Changes in soil ph from Increased ph in all TOV-areas 5,0 Soil ph - all TOV-areas 4,8 4,6 4,4 4,2 4,0 Lund Møsvatn Gutulia Åmotsdal Børgefjell Dividal 3, Analyse periods

19 Changes in soil nutrients More nutrient-rich soil Increased Ca, Mg, K Increased cation exchange capacity Increased base saturation Increased total N

20 Vegetation response to warmer, wetter and longer growth season Field layer Increased temperature leads to more available nutrients Increased cover of competative species Increased growth of herbs and grasses Increased cover of field layer

21 Vegetation response to warmer, wetter and longer growth season Bottom layer bryophytes and lichens Increased growth of large mosses in southern areas 6 Average cover of 50 plots Lund area, southern Norway % P < Hylocomium splendens Sphagnum quinquefarium 1 P <

22 Vegetation response to warmer, wetter and longer growth season Increased cover of field layer (herbs and grasses) Less light to the ground Increased competition for light Decreased abundance of non-competative species Decreased abundance of liverworts and lichens

23 AVERAGE COVER % Vegetation response to Nitrogen Increased abundance of grasses 10 8 Molinia caerulea (average cover of 50 plots) Lund area southern Norway P < Decreased abundance of lichens Absent in the southernmost area Lund

24 Vegetation response to less acid rain Increased accessibility of soil nutrients Increased plant diversity Increase in nutrient demanding species

25 Summary Climate change: Warmer and wetter climate Reduced acid rain Minor changes in N-deposition Increased temperature and precipitation leads to a more productive field layer, consisting of herbs and graminoids Competition for light reduce the abundance of liverworts and lichens Decreased sulphur deposition has lead to less acidification and more nutrient-rich soils High nitrogen deposition has over time increased the abundance of grasses in southern Norway

26 Conclusions The TOV-monitoring approach shows fast responses in vegetation, caused by broad scale environmental impacts The forest ground vegetation contains a large set of sensitive indicators of environmental change The monitoring concept also allows for using vegetation response for early detection of small changes in the environment A great dataset for predicting future changes in vegetation and the environment

27 Thank you for your attention! The Norwegian sub-alpine birch-forests in future?