Karen Booth

Investigation into the foraging behaviour of bumblebees on varying

flowering vegetation, across the habitats of the RSPB reserve,

Dungeness, Kent.

Overall Aims

• Assess which habitats, on the RSPB reserve, Dungeness, Kent, are most suitable for the re-introduction of Bombus subterraneus.

• Replicate and manage habitats.

Grassland(managed to provide a legume rich sward)

Semi-natural vegetated shingle

Rank vegetation at the margins of wetlands

Grazed Field

Bombus subterraneus

Research Questions

1. How does the abundance of each recorded species of current Bombus vary across the four habitats?

2. How does the total number of Bombus sightings vary across the four habitats?

3. Which habitat contains the greatest abundance of flowering vegetation preferred by Bombus subterraneus?

4. Which current Bombus species prefer to forage on which flowering vegetation family across the four habitats?

Study Design• 18th of July to 1st August 2009.• Females actively foraging for nectar and pollen. • Between the hours of 8.30am and 5.00pm.• Five 20x20m ‘working quadrats’.• Three 15 minute bee walks conducted in each working

quadrat. • Foraging Bombus species and flowering vegetation were

identified.• Unidentifiable Bombus individuals were caught in the

meshed sample pot and inspected. • 20 random small quadrats were thrown in each working

quadrat. • Flowering vegetation within the quadrat was identified

and recorded.

Further inspection of specimen

Quadrat

Results

0

50

100

150

200

250

300

B. te

rre

str

is/lu

co

rum

B. la

pid

ari

us

B. p

rato

rum

B. h

ort

oru

m

Gin

ge

r b

ee

s

B. te

rre

str

is/lu

co

rum

B. la

pid

ari

us

B. p

rato

rum

B. h

ort

oru

m

Gin

ge

r b

ee

s

B. te

rre

str

is/lu

co

rum

B. la

pid

ari

us

B. p

rato

rum

B. h

ort

oru

m

Gin

ge

r b

ee

s

B. te

rre

str

is/lu

co

rum

B. la

pid

ari

us

B. p

rato

rum

B. h

ort

oru

m

Gin

ge

r b

ee

s

Grassland Shingle Wetland Grazed

Habitat and Bombus species

Po

ole

d t

ota

l n

um

be

r o

f v

isit

s r

ec

ord

ed

Pooled total number of Bombus visits recorded across four habitats ± standard deviation, collected July/August 2009, Dungeness, Kent, UK.

• Grassland had significantly greater Bombus hortorum than other habitats (F ratio > F critical value).

• Wetland had significantly greater abundance of ‘ginger bees’ than other habitats (F ratio > F critical value).

Objective 1

-100

0

100

200

300

400

500

600

700

grassland habitat shingle habitat w etland habitat grazed habitat

Habitat

Po

ole

d t

ota

l nu

mb

er o

f Bombus

sig

hti

ng

s p

er h

abit

at

Pooled total number of Bombus sightings recorded across four habitats ± standard deviation, collected July/August 2009, Dungeness, Kent, UK.

Objective 2

• Grassland had significantly greater Bombus sightings than other habitats (F ratio > F critical value).

0

100

200

300

400

500

600

700

800

white

clo

ver -

Trif

olium

repe

ns

bird

's fo

ot tr

efoi

l - L

otus

corn

icula

tus

com

mon

vet

ch -

Vicia

sativ

a

less

er h

awkb

it - L

eont

odon

sax

atilis

wild te

asel

- Dip

sacu

s fu

llonu

m

bram

ble

- Rub

us fr

utico

sus

blac

k m

edick

- M

edica

go lu

pulin

a

yello

w mel

ilot -

Mel

ilotu

s of

ficin

alis

fleab

ane

- Pul

icaria

dys

ente

rica

viper

's bu

glos

s - E

chium

vul

gare

mea

dow v

etch

ling

- Lat

hyru

s pr

aten

sis

tufte

d ve

tch

- Vici

a cr

acca

Flowering plant species

Po

ole

d t

ota

l re

co

rde

d n

um

be

r

Pooled total number of flowering plant species recorded across the wetland habitat ± standard deviation, collected July/August 2009, Dungeness, Kent, UK.

Objective 3

• Only habitat to hold specific Bombus subterraneus preferred species of flowering vegetation including viper’s bugloss (Echium vulgare), yellow melilot (Melilotus altissima), common teasel (Dipsacus fullonum) was wetland habitat.

Objective 4

• Wetland habitat: Bombus terrestris/lucorum prefers the pooled recorded species of the Borage family (including just viper’s bugloss).

• Wetland habitat: the pooled ‘Ginger Bees’ prefer the pooled recorded species of the Borage family (including just viper’s bugloss).

Conclusions

Importance of bumblebees • Decline in British bumblebee abundance; loss of numbers

can result in changes in plant communities, and associated herbivore communities (Goulson et al., 2005).

Why has this decline occurred?• Intensified farming practices (Osborne & Corbet, 1994)

(Carvell, 2002).

Conclusions Relating findings to the future• Bombus hortorum and the ‘ginger bees’ are both long-tongued

species like Bombus subterraneus.

• Grassland habitat should perhaps be replicated and continued to be managed sufficiently.

• Wetland habitat should perhaps be replicated and continued to be managed sufficiently.

• Vegetation at the edge of the wetlands had greatest abundance of plants preferred by Bombus subterraneus, including common teasel, viper’s bugloss and yellow melilot. Survey areas and control invasive species.

• Extra effort into managing and increasing populations of viper’s bugloss on wetland habitats.

Questions?