Controlling Gunnera tinctoriaWhere are we today?

By: Cristina Armstrong and Bruce Osborne

Background

Gunnera tinctoria is an invasive plant to the west of Ireland.

Established on Achill Island, possibly over 100 years.

Native to Southern regions of South America, similar climatic conditions

Large herbaceaous perennial plant growing over 2m tall and with up to 2m wide leaves.

Outline

Started in 2006 – Msc at UCD (Control & Mapping)

Greenhouse experiments

Field experiments

Mapping

Eradication?

Mapping Using field boundaries as a site:Presence/absence of G. tinctoria marked out.

At each site:Percentage cover

Stand TypeSize (L,M,S)Habitat

Total Area Invaded

4.2 km2

= 2.9 %

0.69 km2

= 0.46 %

Area = 55 football pitches!!

Rivers and Waterways

Distribution along rivers

15.6%

Roadsides and paths

Distribution along roadsides

30.1%

Distribution within 50 m of buildings

49.2%

Agricultural land

Peat bogs

Quarries and disturbed land

Heath

Coastal Cliffs

Possible means of spread

Short range dispersal Seed falls near parent plant

Long range dispersal Rivers and roads Habitat corridors Disturbance Birds

Greenhouse ExperimentsBefore

After

Concentration of RoundUp

RoundUp V Garlon

Leaf area

Recommended concentration

Garlon fast-acting

Leaf area not significant

Field Experiments

1.

4 x 4 m plots

RoundUp

Two methods of application:

Cut and Paint

Cut and Injection

2.

4 x 4 m plots

RoundUp V Garlon

Timing of application

Selective

Results

0

5

10

15

20

25

Cut & P aint Cut &Injec tion

Control C& P Control C& I Control

Tre a tm e nt

Nu

mb

er o

f n

ew s

ho

ots

M ean S tart A ug 06

M ean M arch 07

M ean A pril 07

M ean M ay 08

96%

83%

61%

75%

Re-application needed after 2 years!!

When is the best time to apply?

Early applications were not successful

How to treat each plant

Cut, Inject and Spray

Current Work

Eradication on Clare Island

Biodiversity Grant (Heritage Council) Mapping Methods used in experiment Island involvement Future monitoring

Conclusions Main habitats invaded:

Agricultural land Waterways Roadsides Disturbed land

Hypothesised that disturbance is facilitating the spread.

Re-application of treatments required Other measures of control (physical,

biological)

Acknowledgements

Bruce Osborne for his supervision. Javier, Angeles, Noeleen, Ale, Margherita, Mark,

Lisa, Michael Bob and John for all their field assistance.

Ray for his advice on greenhouse expt. Mayo County Council.

- Carmel & Louise in GIS

- Deirdre Cunningham Heritage Council – Funding