UK alpine habitats are experiencing changes in biodiversity due to multiple drivers. Surveys from 1960-1980 were resampled in 2004-2006, finding mean species richness increased but diversity declined. Higher plants increased most in snowbeds and springs, while bryophytes increased in fell fields. Experiments show calluna heath and lichens decline with nitrogen addition and calluna extends with warming. Multiple factors like pollution deposition, climate change, and land use are contributing to the expansion of sub-alpine species and decline of alpine specialists.

1. Drivers of biodiversity
change in British alpine
habitats
Andrea Britton, Alison
Hester, Colin Beale, Richard
Hewison & Willie Towers

2. UK alpine habitats
 Wide variety of habitats
 Strong oceanic influence
 Important role of lower
plants
 High biodiversity value
 Ecosystem services
 C storage
 Water cycle

3. Anthropogenic impacts
Local scale drivers:
 Recreation impacts
 Hiking
 Skiing
 Grazing
 Management

4. Anthropogenic impacts
Sulphur deposition
Pollutant deposition:
 Sulphur
 Deposition declining
 Persistent effects
 Nitrogen
 Deposition remains
high
Source: www.apis.ac.uk
Source: ROTAP 2010

5. Anthropogenic impacts
Climate change: 1961-2004
 Temperature
 Average 1°C rise since 1961
 Precipitation
 60% increase in winter rainfall
 Snowfall
 30% reduction in days with
snow cover

6. Alpine vegetation is exposed to multiple
drivers of change…
How has biodiversity responded over
the last 40 years?

7. Birse and Robertson Survey
 700+ plots recorded 1960-1980
 205 plots resurveyed 2004-6
 Range of typical alpine communities
 Recorded species composition & sward
structure

8. Overall change: plot scale
 Mean species richness  Plot-level diversity
increased from 16 to 19 (Shannon) has declined
25 2.0 ***
***
Mean Shannon Index H'
Mean species richness
20 1.5
15
1.0
10
0.5
5
0 0.0
old new Old New

9. Overall change: landscape scale
 New sill is significantly lower (P<0.001)
 Spatial turnover of composition reduced – more homogeneous
Old data New data

10. Habitat specific changes
 Richness change
differs between 4
Mean change in species richness
higher plants and Highers
Bryos
bryophytes 3
 Higher plants
increase most in 2
snowbed and
springs, no change 1
in fell field
0
 Bryophytes increase
most in fell field, he
ath eath eath l field wbed rings land land land
s
h
na ium rium
h l
Fe Sno Sp rass ras grass
decline in tall Juncus llu in
Ca acc comi
t G sG s
du
cu
V a un Nar
grassland R J

11. Species trends
Winners: Losers:
 Middle altitude, widespread  High altitude, northern species
species

12. How do observed changes compare with
experimental studies?

13. Example: Alpine Calluna heath
 Changes in survey plots:
 Increased higher plant and
bryophyte richness
 Increased Calluna cover
 Reduced lichen cover
 Increased sward height

14. Culardoch long-term experimental site
 Nitrogen addition  Grazing
 Warming (open top chambers)  Burning

15. Driver responses – Higher plants
 Survey finding: increased 40
35
Mean shoot extension (mm)
Calluna cover
30
 Experimental response: 25
20
 Positive response to 0 kg N
10 kg N
both N addition and 15 20 kg N
50 kg N
warming 10
1998 2000 2002 2004 2006 2008 2010
 Increased shoot
Year
growth 45 OTC's
installed
-OTC
 Increased flowering 40 +OTC
Mean shoot extension (mm) 35
 No change in species 30
composition (after 10 25
20
years) 15
10
1998 2000 2002 2004 2006 2008 2010
Year

16. Driver responses - lichens
 Survey finding: decreased
lichen cover 10
 Experimental response: 8
Lichen species richness
rapid decline in cover and 6
richness with N addition
4
 Sensitive to low loads & 2
concentrations
0
0 kg 10 kg 20 kg 50 kg
 Lichen abundance also N addition (kg N ha-1 y-1)
related to sward height –
indirect effect of climate
and/or grazing

17. Conclusions
 UK alpine habitats are changing
 Species of sub-alpine habitats are expanding while alpine
specialists decline
 Nature of change is habitat specific
 Experimental studies show that multiple drivers can contribute
to observed changes
 Future studies: avoid considering single drivers in isolation

18. Acknowledgements
Scottish Government & DEFRA for funding
Julia Fisher, Dave Riach and Heather Armitage
for help with field work
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