The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola...

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The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James O’Keefe

Transcript of The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola...

Page 1: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

The diet of the Eurasian badger (Meles meles) in the Republic of Ireland

Gráinne Cleary, Nicola Marples, Leigh

Corner & James O’Keefe

Page 2: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Why this is new

• First Republic of Ireland sample

• Results will help with BCG vaccine program

• Large sample size based on stomachs

• Badgers in Ireland have narrow niche breadths

Page 3: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Dietary Niche Breadth BS = (B-1) / (n-1)

Specialist

Generalist

0

1

Page 4: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Section 1The diet during each season is examined

followed by the dietary niche breadth

Spring Summer

Autumn Winter

Page 5: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Section 2

Feeding trails on captive badgers to estimate

- passage rate

- assimilation efficiency

Results help to understand foraging strategy which may be related to dietary niche breadth

Section 3

Summary of results

Page 6: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Section 1

What do badgers eat?

Page 7: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Spring

Page 8: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Dietary niche breadth = 0.23

Specialist

Generalist

0

1

Page 9: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Summer

Page 10: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Dietary niche breadth = 0.40

Specialist

Generalist

0

1

Page 11: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Autumn

Page 12: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Dietary niche breadth = 0.26

Specialist

Generalist

0

1

Page 13: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Winter

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Dietary niche breadth = 0.44

Specialist

Generalist

0

1

Page 15: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

To sum up…

Seasonally, the diet is dominated by a couple of food items and therefore the badgers have a narrow niche breadth

Spring Tipulid Larvae BS = 0.23

Summer Frogs BS = 0.40 Bees & Wasps

Autumn Noctuid Larvae BS = 0.26

Winter Noctuid Larvae BS = 0.44 Frogs

Page 16: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Section 2

Feeding trails

Page 17: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Why does the badger have such a narrow dietary niche breadth?

Page 18: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Food items passed rapidly through the gastrointestinal tract

– After 7 hours only one badger’s stomach still had traces of food

– After 16 hours the colon only had traces of selected food items

Results showed that…

Page 19: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Stomach and faecal samples suggest that during periods of prey abundance badgers gorge.

Therefore food passes rapidly through the gut resulting in low assimilation efficiency and food wastage.

Combined with results from dietary analysis…

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Other mustelids also have low assimilation efficiency

• Mink (Mustela vision) – Errington (1967)

• North American Badger (Taxidea taxus) – Harlow (1981)

• Weasel (Mustela nivalis) – Moors (1977)

• Wolverine (Gulo gulo) – Farrell and Wood (1968)

• Sea Otters (Enhydra lutris) – Iversen (1972)

Page 21: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Why does the badger have such a narrow dietary niche breadth?

Species with low absorption efficiency may eat fewer food items = narrow niche breadth

Species with high absorption efficiency eat more prey types = broader niche breadth

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Section 3

To Sum Up,

We tentatively suggest that…

Page 23: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Due to low assimilation efficiency badgers have a narrow dietary niche

breadth composed of high-quality foods

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Low ingested biomass of earthworms compared to UK

This could be due to insect larvae having a higher engery

content

Page 25: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Huge intake of vegetation may be involved in slowing down passage

time through the gut?

Could this result in higher assimilation efficiency?

Page 26: The diet of the Eurasian badger (Meles meles) in the Republic of Ireland Gráinne Cleary, Nicola Marples, Leigh Corner & James OKeefe.

Acknowledgements

• Mr. Bill Coleman • Dept of Agriculture &

Food• Dr. Ursula Fogarty• Staff at IEC• Staff at Abbotstown farm• Ms. Alison Boyce• Mr. Peter Stafford• Ms. Lynsey Stuart

Lynsey Stuart