the scottish freshwater group 100th meeting, stirling
TRANSCRIPT
UCL DEPARTMENT OF GEOGRAPHY
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Environmental change in Scottish lochs
revisited
Helen Bennion & Rick Battarbee
The Scottish Freshwater Group 100th Meeting, Stirling, April 2018
In the ECRC we have been principally interested in the use of long-term
records to understand how and why lake ecosystems change in time and
space and in particular how they respond to pressures from human activity
Coring
DiatomsLakes with core data
Indicators
Plant macrofossils
Cladocera
Upland waters - Rick
• Palaeolimnological evidence for the impact of acid deposition
• Evidence for recovery from the Upland Waters Monitoring
Network
(also see talk by Ewan Shilland)
Lowland waters – Helen
• Understanding of timing, rates and causes of eutrophication
• Determining baselines and degree of ecological change
• Ecological response to enrichment
• Insights into climate-nutrient interactions
• Assessing recovery from eutrophication
• Informing conservation of rare species
(see talk by Isabel Bishop)
Environmental change in Scottish lochs - revisited
SNH, 2002
Loss of brown trout populations in Scandinavia and Scotland
And many other countries in Europe and North America
Loch Fleet, Scotland
Holmevatn, Norway
Turnpenny 1992 Restoring Acid Waters, Elsevier
1950
Maitland et al. 1987, Natural Environment Research Council
Overrein et al. 1980 SNSF Project FR 19/80
The “acid rain” debate
Britannica Student EncyclopediaRatcliffe-on-Soar
Sulphur emissions from coal and oil burning?
Or post-war afforestation of moorland?
From Harriman & Morrison 1982
Data fromLoch Ard burns
Galloway,
Scotland
Lochs on the granites in Galloway, with and without afforested catchments
Talnotry 1980
changes in diatomassemblage composition:
ca. 1750 - 1985
Flower & Battarbee 1983, Nature, 305, 130-133; Jones, et al. 1989, J. Ecology 77, 1-23
At the Round Loch of Glenhead, with a moorland catchment, acidification began in
the mid 19th century
Palaeolimnology played its part in persuading Margaret Thatcher and the UK
Government in 1987 to sign up to international protocols requiring S and N gas
emissions to be reduced from UK power stations
• UNECE Oslo Protocol on Further Reduction of Sulphur
Emissions (second sulphur protocol) 1994
• UNECE Gothenburg Protocol to Abate Acidification,
Eutrophication and Ground-level Ozone, 1999
• EU Proposal for a National Emission Ceilings Directive
(NECD) (1999)
• EU Water Framework Directive (WFD) (2000)
Current Directives and Protocols
Photos: E Shilland
(a) (b)
(c) (d)
(e) (f)
Low alkalinity lakes and streams in high and low acid deposition areas, with and without forestry
CL-E (1990)
The Acid (now Upland) Waters Monitoring Network (from 1988)
Eight sites in Scotland
The UWMN is run by a research consortium including CEH, MSS, QMUL and UCL and it is now
co-ordinated by CEH and funded by WAG, NRW, SNH, FC and NIEA.
UK Sulphur dioxide emissions 1970-2020
UK NOx emissions 1970-2020
RoTAP, 2012, Defra, UK
1988
UK emissions
-20
-10
0
10
20
30
40
50
60
70
80
1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014
no
n-m
ari
ne s
ulp
hate
(µ
eq/L
)Non-marine sulphate (1988 – 2015), comparing non-acidified sensitive “clean” control sites in north-west
Scotland, with two acidified sites in SW Scotland (Round Loch of Glenhead) and N Wales (Llyn Llagi)
Loch Coire nan Arr Round Loch of Glenhead Llyn Llagi Loch Coire Fionnaraich
4
5
6
7
1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014
pH
pH (1988-2015) comparing sensitive (Coire nan Arr, Coire Fionnaraich) and less sensitive (Burnmoor Tarn) “control” sites with two acidified sites (Llagi and RLGH)
Loch Coire nan Arr Round Loch of Glenhead
Burnmoor Tarn Llyn Llagi
Loch Coire Fionnaraich
2008
Battarbee et al. Ecological Indicators, 2014, 37, 365-380
Sediment core (1790 – 1990) + sediment trap (1991- 2013)E Shilland
Some recovery after 1995 , but return to more acid tolerant
diatom assemblages after 2008
Round Loch of Glenhead
Recovery?
1800
2008
1800
2013
PCA of diatom assemblage data from the Round Loch of Glenhead
combining sediment core data (red) and sediment trap data (blue) and comparing
trajectories from 1800 AD to 2008 AD and 1800 AD to 2013 AD
Battarbee et al. Ecological Indicators, 2014, 37, 365-380
2008
Increased precipitation exacerbated by sea-salt rich storms leads to lower pH
in runoff from base poor soils
Monteith, personal communication http://www.kayarchy.co.uk/html/03thesea/008predicting.htm
Climate change
Acidification and climate change - summary
• Acidification caused by sulphur and nitrogen deposition from fossil-fuel combustion
• UK emissions of sulphur dioxide and nitrogen oxides have declined greatly since 1980
• Chemical and biological data from the Upland Waters Monitoring Network show signs of
recovery during the 1990s but little improvement since ca. 2008
• Increasing precipitation coupled with increasing storminess may be causing more acidic
runoff, inhibiting further recovery
Lowland waters
Assessing eutrophication and reference conditions for Scottish freshwater lochs using subfossil diatoms
1. Understanding of timing, rates and causes of eutrophication
Bennion et al. (2004) Journal of Applied Ecology
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Do
wn
-co
re d
ep
th (
cm
)
4
3
2
1
0
Aulac
oseira
dista
ns
0
Cyc
lote
lla (c
f. ro
ssii)
0 20
Cyc
lote
lla k
uetzingi
ana
var.
plan
etop
hora
0 20
Bra
chys
ira vitr
ea
0
Fragila
rifor
ma
exigua
0 20
Ach
nant
hidi
um m
inut
issim
um (a
gg.)
0
Enc
yone
ma
grac
ile
0
Eun
otia in
cisa
0
Frustul
ia rh
ombo
ides
0
Ach
nant
hidi
um sub
atom
oide
s
0
Relative abundance (%)
Ach
nant
hidi
um ro
sens
tock
ii
0
Tabellaria
fene
stra
ta
0 20
Tabellaria
floc
culo
sa (s
hort)
0 20
Tabellaria
floc
culo
sa (l
ong)
0
Ach
nant
hes
saxo
nica
0 20
Aster
ione
lla fo
rmos
a
0
Fragila
ria cap
ucina
var.
grac
ilis
0 20 40 60
Aulac
oseira
sub
arctica
0 20 40
Fragila
ria cro
tone
nsis
0
Eun
otia tr
iden
tula
3 6 9 12 15 18
N2
Hill'
s N2
-0.3 0.0 0.3 0.6 0.9
Sample score
PCA A
xis 1
0 5 10 15 20
ug L-1
DI-T
P
0.5 1.0 1.5
SCD units
SCD
0 20 40 60
%
% p
lank
ton
1860187018801890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
2010
Ra
dio
me
tric
da
tes
(A
D)
Increasing pressures in the catchment during the mid to late twentieth century:
- 1950s dam construction / water level
- 1960s forestry plantation and fertilisation
Mid-1990s the most marked changes are coincident with the arrival of the fish
farms on the loch in 1994-1995
1. Identifying causes of enrichment e.g. Loch Shin
Bennion et al. (2016) Report to SEPA & the Forestry Commission
Scores: 0 to 20: exactly the same2: completely different
<0.3 significantly similar at the 1st percentile<0.4 significantly similar at the 2.5th percentile<0.5 significantly similar at the 5th percentile<0.6 significantly similar at the 10th percentile
Squared chord distance measures
of floristic (diatom) change
Top
Bottom(c 1850 AD)
Site name Site code SCD
Loch Awe North AWEN 0.6575
Loch Awe South AWES 0.7395
Loch of Butterstone BUTT 0.6720
Carlingwark Loch CARL 1.0979
Castle Loch CASL 1.1471
Castle Semple Loch SEMP 1.1793
Loch Davan DAVA 0.5439
Loch Doon DOON 1.2136
Loch Earn EARN 1.6281
Loch Eck ECK 0.4138
Loch Eye EYE 0.8250
Loch of Harray HARY 0.7907
Kilbirnie Loch KILB 1.3653
Loch Kinord KINO 0.3135
Loch Leven LEVE 0.7974
Loch Lomond North LOMON 0.2199
Loch Lomond South LOMOS 0.6585
Loch of the Lowes LOWE 1.1771
Loch Lubnaig LUBN 0.2224
Loch Maree MARE 0.1291
Lake of Menteith MENT 0.9438
Mill Loch MILL 0.6831
Loch Rannoch RANN 0.2526
Loch Shiel SHIE 0.2439
Loch of Skene SKEN 0.8665Bennion & Simpson (2011) JOPL
2. Determining baselines and degree of ecological change
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
Dept
h (c
m)
3
2
1
0 20
Cyc
lote
lla c
omen
sis
0 20
Cyc
lote
lla p
seud
oste
llige
ra
0 20
Cyc
lote
lla ra
dios
a
0 20
Ach
nant
hes
min
utissim
a
0 20
Fragila
ria con
stru
ens
var.
vent
er
0 20
Fragila
ria cap
ucina
var.
grac
ilis
0 20 40
Aster
ione
lla fo
rmos
a
0 20 40
Fragila
ria cro
tone
nsis
0
Aulac
oseira
am
bigu
a
0
Aulac
oseira
gra
nulata
0 20
Ste
phan
odiscu
s pa
rvus
0 20 40 60 80 100
%
% p
lank
ton
1900
1920
1940
1960
1980
2000
Date
(AD)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
Dept
h (c
m)
0 20 40 60 80
Bos
mina
long
irostris
0 20
Chy
doru
s sp
haer
icus
0 20
Alone
lla e
xigu
a
0
Alone
lla n
ana
0 20
Gra
ptoleb
eris te
stud
inar
ia
0
Alona
gut
tata
var
tube
rculat
a
0
Alona
inte
rmed
ia
0
Alona
qua
dran
gularis
0
Alona
cos
tata
0
Alona
gut
tata
0
Alona
rectan
gula
-1.0 0.0 1.0 2.0
PCA a
xis 1
1840
1860
1880
1900
1920
1940
1960
1980
2000
Date
AD
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
Depth
(cm
)
0 10
Cam
ptoc
ercu
s re
ctiro
stris
0 20 40
Leyd
igia
spp
0 20 40
Sim
ocep
halus
spp
0 20 40
Number per 100cm3
Chy
dorid
spp
0 80 160
Dap
hnia
hya
lina
agg
0 20 40
Cer
ioda
phnia
spp
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
Depth
(cm
)
4
3
2
1
0 20 40
Pot
amog
eton
cris
pus
turio
n sp
ines
0 40 80
Pot
amog
eton
spp
(bro
ad) l
eaf f
ragm
ents
0 20 40
Pot
amog
eton
spp
(fin
e) le
af fr
agm
ents
0 20 40
Pot
amog
eton
tips
0 50 100 150
Callitric
he s
eeds
0 20 40 60
Cha
ra o
ospo
res
0 200 400
Nite
lla s
pp. o
ospo
res
0 40 80
Cer
atop
hyllu
m spi
nes
0 50 100 150
Nym
phae
a alba
see
d fra
gmen
ts
0 40 80
Nym
phae
acea
e try
chos
cler
eids
0 10
Zannich
ellia
palus
tris
seed
s
0 200 400
Najas
flex
ilis sp
ines
Diatoms Cladocera
Ephippia Plant macrofossils
3. Ecological response to enrichment e.g. Loch Monzievaird
1900
1980
1900
1980
O
O-M
M-E
The two approaches combined give a
more complete picture of macrophyte
community change over time than
either method in isolation
Comparison of palaeo and historical records for Loch Leven
4. Value of combining long-term and palaeoecological datasets
Salgado et al. (2010) JOPL
Oligotrophic-
mesotrophic lake
with
characteristic
soft-water
macrophytes
Early influence of
nutrient-
enrichment and
promotion of a
taller growing
elodeid
community
A more nutrient-rich
flora and more
organic sediments
(following lake
lowering)
LEVE12 summary diatom diagram: short term record
Bennion et al. (2012) Freshwater Biology
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
Dep
th (c
m)
0 20
Aster
ione
lla fo
rmos
a
0 20
Cyc
lote
lla ra
dios
a
0
Cyc
lote
lla p
seud
oste
llige
ra
0 20 40
Ste
phan
odiscu
s pa
rvus
/minut
ulus
0 20
Ste
phan
odiscu
s ha
ntzs
chii
0 20
Aulac
oseira
am
bigu
a
0 20 40
A. g
ranu
lata
var
. ang
ustis
sim
a
0 20
Aulac
oseira
gra
nulata
0 20 40
% relative abundance
Aulac
oseira
sub
arctica
0
Fragila
ria cro
tone
nsis
0
Diato
ma
tenu
is
0
Syn
edra
acu
s va
r ang
ustis
sim
a
0
Cyc
lostep
hano
s th
olifo
rmis
0 20
Cyc
lostep
hano
s in
visita
tus
0 20
Cym
bello
nitz
schia
diluvian
a
0 20
Fragila
ria spp
.
0 20 40 60 80 100
% 'w
arm
' tax
a
0 20 40 60 80 100
% 'c
ool' ta
xa
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
Dat
e (A
D)
Enri
chm
ent
Recovery
sta
rts
=High winter-
spring temps
5. Insights into climate-nutrient interactions e.g. Loch Leven
Low % High %
=wet winters
High %
Marsworth
Reservoir,
England
Timetracks of diatom
shifts in shallow lake
cores plotted
passively on a PCA of
training set samples
C. comensis
Ach minutissimaB. vitrea
Tab flocculosa
C. radiosa
Stephs/
Cyclostephs
A. ambigua/ A, subarctica
A. formosa & F. crotonensis
C. pseudostelligera/
C. meneghinianaLoch Leven,
Scotland
Llangorse
Lake, Wales
Benthic Fragilaria spp
Bennion et al. (2015)
Frontiers in Ecology and Evolution
6. Assessing recovery trajectories and timescales
enrichment
recovery
Recent responses of Scottish freshwater lochs to changes in nutrient loading
and climate change
Lucia Lencioni
SNH funded PhD studentship
UCL
6. Assessing recovery trajectories and timescales
Aims:
• Compare contemporary diversity to pre-1850s diversity within 24 lakes
(Glasgow, Cumbria, Norfolk).
• Pre-1850 used as ecological reference state.
• Focus on plants, diatoms and caddisflies across the 3 Hydroscapes.
• Identify biodiversity loss over time for key sites and locate biodiversity
refuges in the surrounding landscape.
6. Assessing recovery trajectories and timescales
e.g. Loch Libo
Loch Libo
Elatine hydropiper Eight-stamened Waterwort
0
0
15
10
5
0
d[, i]
yva
r
0 1
Elatin
e hy
drop
iper
d[, i]
yva
r
0 2
Sphag
num
sec
tion
Subse
cund
a
d[, i]
yva
r
0 5
Sphag
num
sp.
d[, i]
yva
r
0 80
Potam
oget
on o
btus
ifoliu
s
d[, i]
yva
r
0 4
Junc
us see
d
d[, i]
yva
r
0 5
Car
ex sp.
d[, i]
yva
r
0 250
Cha
ra o
ospo
re
d[, i]
yva
r
0 120
Nite
lla o
ospo
re
d[, i]
yva
r
0 20
Callitric
he see
d
d[, i]
yva
r
0 60
Lem
na tr
isulca
leaf
d[, i]
yva
r
0 15
Potam
oget
on (t
hin-
leaf
)
d[, i]
yva
r
0 30
Cris
tate
lla m
uced
o stat
oblast
d[, i]
yva
r0 1
Plum
atella sta
toblas
t
d[, i]yva
r
0 8
Cer
ioda
phnia
ephipp
ia
d[, i]
yva
r
0 3
Dap
hnia p
arvu
la e
phippia
d[, i]
yva
r
0 15
Dap
hnia p
ulex
eph
ippia
d[, i]
yva
r
0 7
Cad
disfly
d[, i]
yva
r
0 500
Gloeo
itrichia
SEM picture: Marja Uotila, Flora Nordica:
http://www.floranordica.org/Review/-ill-
html-filer/ill_Elatine_ms.html
Loch Libo, Greater Glasgow, 1850 compared to today
6. Assessing recovery trajectories and timescales
Data by Carole
Roberts &
Ambroise Baker
Bardowie
Top Sed. ☺
1850s ??
Elatine hydropiper, Glasgow, 1850 and today
C.Semple
Top Sed. ☺
1850s ☺
Loch Libo
Top Sed. ×
1850s ☺
Lochend
Top Sed. ??
1850s ??
Today’s distribution
Plant macrofossil data
6. Assessing recovery trajectories and timescales
NBN Atlas https://nbnatlas.org/
7. Informing conservation of rare species
Understanding the habitat and decline of
Najas flexilis (Willd.) Rostk. & Schmidt in the
UK using ecology and paleoecology
Isabel Bishop - PhD
SNH, UCL-IMPACT
Using palaeolimnology to understand the
ecology of a rare bird species – common
scoter
Hannah Robson - PhD
UCL-IMPACT, SNH, WWT
See talk by Isabel Bishop on Friday
1. Fuller understanding of timing, rates and causes of eutrophication and acidification in Scottish fresh waters
2. Better definition of baselines (reference conditions) and degree of ecological change
3. More complete understanding of ecological response
(a shift away from chemical inferences to ecological response)
4. Long-term and palaeoecological datasets used increasingly in combination,
e.g. for disentangling multiple stressors, assessing variability
4. Greater insights into climate-nutrient interactions
5. An assessment of recovery trajectories and timescales – confounding factors
6. Informing conservation of rare species
Future/ongoing research:
- Legacy pollutants, food-chain effects, remobilisation (Neil Rose’s work)
- Emerging pollutants, e.g. microplastics
- Recovery pathways – in light of climate change and other stressors
- Role of connectivity (NERC Hydroscape)
Summary: Environmental change revisited
Any questions?
Thank you to numerous colleagues for providing ideas and data, especially
Viv Jones, Neil Rose, Simon Turner, Handong Yang, Carl Sayer, Ewan
Shilland, Isabel Bishop, Lucia Lencioni, Hannah Robson, Gina Clarke, Tom
Davidson
‘Sampling’ Scottish lochs