the scottish freshwater group 100th meeting, stirling

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


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.


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


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


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

the scottish freshwater group 100th meeting, stirling

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