Assessment of the impact of cattle access points on aquatic biota

o Introduction

o Impacts of cattle access and grazing

o Aims

o Site Selection

o Methods

o Data analysis

o Results

o Concluding comments

o Future work

Outline

Introduction

o Agriculture accounts for 67% of total land use (4.5 million hectares) in the republic of Ireland (DAFM 2013)

o Of this agricultural land within the Republic of Ireland, c. 81% (3.67 million hectares) is devoted to grass

o Economic importance

o EU Water Framework Directive (Directive 2000/60/EC) o Achieve or maintain ‘good’ ecological status by 2015

o Agri-environmental (AE) schemes

o Common Agricultural Policy (CAP)

o Key policy mechanisms protecting ecosystems and conserving

natural resources (Finn & Ó hUallacháin, 2011).

Potential impacts of cattle access

o Channel stability (Trimble and Mendell 1995) o Sediment and nutrient loading to rivers o Cattle defecating and urinating o Resuspension

o Species, age and stocking density (Line et al., 2000; Davies-Colley et al.,

2004; Bilotta et al 2007: Wilkes et al., 2013)

Aims

This study investigated the impact of cattle access on macroinvertebrate composition in a range of Irish river Questions to Answer: 1. What are the effects, if any, of cattle access on aquatic macroinvertebrate

community composition and structure 1. Is there a relationship between univariate biological metrics and various

measures of deposited sediment

Ecdyonurus spp. Baetis rhodani

B. risi A. sulcicollis

o Desk top study o Numerous site visits

Site selection

Selection of site visit photographs

Cattle access study sites

Cattle access

point

Direction of flow

Downstream sampling location

Upstream sampling location

Riffle c. 5-7 x channel

width

Riffle c.5-7 x channel

width

Schematic showing control, upstream and downstream sampling locations

o Sampling locations c. 5-7 times channel width of each stream

o Spring & Autumn 2013 (patch & reach scale)

Six replicate surber samples Two habitats (mid channel &margin) Upstream and downstream locations

o Autumn 2013

Additional control location on four sites

o 432 Surber samples

Methods

Control sampling location

Riffle c. 5-7 x channel

width

Methods (cont’d.)

o Three methods of measuring deposited sediment Estimation of % sediment surface cover

Resuspensable sediment (g/m-2) Turbidity (NTU)

o Sediment chemistry o Water chemistry- base and high flow (ongoing)

Data Analysis o PERMANOVA analysis (across all sites) o Mann Whitney U test (individual rivers) o Generalized linear mixed models (GLMM)

Results – control/upstream mid-channels

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an t

axo

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Upstream

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axo

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Upstream

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Clodiagh Erkina D'arcy's Glenlahan

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EP

T ab

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ce

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Clodiagh Erkina D'arcy's Glenlahan

Me

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EPT

rich

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ss

Mean (+/- standard error) taxon abundance, taxon richness, %EPT abundance and %EPT richness in four rivers at control and upstream sampling locations in Autumn: EPT = Ephemeroptera, Plecoptera and Trichoptera

Results -PERMANOVA analysis

Interactions Taxon

abundance

Taxon

richness

%EPT

abundance

%EPT

richness % E % P %T BMWP

Time X Site (status) X

location x habitat ns ns ns ns ns 0.0002 ns ns

Time X Site (status) X

location 0.003 ns ns ns 0.0006 ns ns ns

Time X Site (status) X

habitat 0.001 ns 0.0032 ns 0.0064 0.0068 ns ns

Time X site (status) 0.0002 0.0002 0.002 0.0002 0.0002 0.0106 0.0002 0.0002

Site (status) X

location 0.0002 0.0002 0.009 0.0002 0.0012 ns ns 0.002

Site (status) X habitat 0.0002 ns ns ns ns ns ns ns

Time = season; site = river; status = good and moderate water quality; location = upstream and downstream; habitat = mid channel and margin. EPT = Ephemeroptera, Plecoptera and Trichoptera, BMWP = Biological Monitoring Working Party : P<0.01.

Results – spring/autumn margins

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Douglas Erkina D'arcys Boycetown Glenlahan Barrow Clodiagh Dee

Taxo

n a

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nd

ance

Upstream

Downstream

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Douglas Erkina D'arcys Boycetown Glenlahan Barrow Clodiagh Dee

Taxo

n a

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nd

ance

upstreamdownstream

Results – spring/autumn mid channels

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Taxo

n a

bu

nd

ance

UpstreamDownstream

**

*

**

**

*

**

Mean (+/- standard error) macroinvertebrate taxon abundance and taxon richness for the Barrow, Clodiagh and Dee rivers at upstream and downstream locations across two sampling season . *p<0.05; **p<0.01

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Spring Autumn Spring Autumn Spring Autumn

Barrow Clodiagh Dee

Taxo

n r

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ss

** **

**

** **

Results – spring & autumn mid-channels

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% E

PT

abu

nd

ance

Upstream

Downstream

*

*

*

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Spring Autumn Spring Autumn Spring Autumn

Barrow Clodiagh Dee

% E

PT

rich

ne

ss

* *

**

Mean (+/- standard error) macroinvertebrate %EPT abundance and %EPT richness for the Barrow, Clodiagh and Dee rivers at upstream and downstream locations across two sampling season . *p<0.05; **p<0.01

Results – spring & autumn mid-channels

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Spring Autumn Spring Autumn Spring Autumn

Barrow Clodiagh Dee

BM

WP

Upstream

Downstream

**

**

**

** *

Mean (+/- standard error) macroinvertebrate Biological Monitoring Working Party (BMWP) for the Barrow, Clodiagh and Dee rivers at upstream and downstream locations across two sampling season (spring and autumn). *p<0.05; **p<0.01

Results – spring & autumn mid-channels

Results Measures of deposited sediment

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Douglas Erkina D'arcys Boycetown Glenlahan Barrow Clodiagh Dee

Sites

Re

sup

en

dab

le s

ed

ime

nt

(g/m

-2)

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se

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Results Sediment chemistry

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1.5

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Upstream Downstream

Tota

l Kje

ldah

l Nit

roge

n

(mgN

/g)

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Upstream DownstreamTP

(m

g P/

g)

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Upstream Downstream

Org

anic

mat

ter

(%)

River/site

TN (mg N/g) TP (mg P/g) Organic matter (%)

u/s d/s u/s d/s u/s d/s

Barrow 0.260 0.313 0.080 0.100 1.0 1.2

Clodiagh 0.190 0.160 0.080 0.103 1.0 1.2

Dee 0.530 0.730 0.520 0.370 2.4 2.7

Across all sites

Sediment chemistry for Barrow, Clodiagh and Dee

Barrow Clodiagh Dee

% surface cover

Increase Decrease Increase

% Organic matter Increase Increase Increase

TN Increase Decrease Increase

TP Increase Increase Decrease

Taxon abundance Decrease Decrease Increase

Taxon richness Decrease Not significant Increase

% EPT abundance Decrease Increase Increase

% EPT richness Decrease Increase Increase

BMWP Decrease Not significant Increase

Summary: Autumn samples (d/s effects)

Results – Relationship between metrics & measures deposited sediment

Preliminary work o Generalized linear mixed models (GLMM)

o Initial results indicate a significant negative relationship between

% EPT richness and % sediment surface cover

o Modelling is ongoing….

Concluding comments o Impacts are site specific o Barrow, Clodiagh and Dee: significant differences in spring and autumn samples for taxon

abundance and richness, % EPT abundance and richness and BMWP

o Clearer impact on rivers which have good status above cattle access points

Measure of deposited sediment: a number of sites showing increased sediment surface cover downstream

Sediment Chemistry: Barrow, Clodiagh and Dee downstream increases in organic matter

Relationship between metrics and measures of deposited sediment: significant negative

relationship between % EPT richness and % sediment surface cover .. Modelling ongoing

Complex effects of cattle access which needs to further assessment

Future work o Monitor sites in real time (e.g turbidity) during period of high usage

(Summer)

o Examine impact of multiple access points

o Measure downstream extent of impact o Examine influence of species, age, stocking density and time spent in

stream

o Measure levels of E. coli and other pathogens o Assess benefits of exclusion measures

Any questions

References

o DAFM 2013. Fact Sheet on Irish Agriculture – October (2013) Department of Agriculture, Food and the Marine

o Davies-Colley, R.J., Nagels, J.W., Smith, R.A., Young, R.G. & Phillips, C.J. (2004) Water quality impact of a dairy cow herd crossing a stream. New Zealand Journal of Marine and Freshwater Research, 38, 569-576

o Finn, J.A., and Ó hUallacháin, D. (2012) A review of evidence on the environmental impact of the Rural Environment Protection Scheme (REPS). Biology and Environment, Vol 112b, 11-35

o Larsen, S. Vaughan, I. P. and Ormerod, S. J. 2009. Scale-dependent effects of fine sediments on temperate headwater invertebrates. Freshwater Biology. 54, 203-219

o Line, D.E., Harman, W.A., Jennings, G.D., Thompson, E.J. & Osmond, D.L. (2000) Nonpoint-source pollutant load reductions associated with livestock exclusion. Journal of Environmental Quality, 29, 1882-1890

o Trimble, S. W. and Mendel, A. C. (1995) The cow as a geomorphic agent – a critical review. Geomorphology, 13, 233-253. o Wilkes., G., Brassard, J., Edge, T.A., Gannon, V., Jokinen, C.C., Jones, T.H., Neumann, N.,

Pintar, K.D.M., Ruecker, N., Schmidt, P.J., Sunohara, M., Topp, E. & Lapen, D.R. (2013) Bacteria, viruses, and parasites in an intermittent stream protected from and exposed to pasturing cattle: Prevalence, densities, and quantitative microbial risk assessment. Water Research, 47, 6244-6257