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.
Drivers of biodiversity change in British alpine habitats [Andrea Britton]
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
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
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
Thank YOU for listening