1) The document discusses the effects of plant invasions on plant-pollinator interactions. It summarizes research showing that invasive plants can negatively impact native plants by competing for pollinator visits and changing community structure.
2) The author conducted research on the breeding systems and effects on pollination networks of three invasive plant species: Carpobrotus aff. acinaciformis, Opuntia stricta, and Impatiens glandulifera. The research found that the invasives are self-compatible but still require pollinators.
3) The research also found that the invasives decreased pollinator visits to native plants and increased the nestedness of pollination
34. Direct effects
CompetitionFacilitationCompetition No effect
Bjerkens et al.(2007)Biol Cons
Totland et al.(2006)J Bot
Larson et al.(2006)Biol Cons
Nilsen et al.(2008)Biol Inv
Muñoz & Cavieres (2008)J Ecol
et al...
Seed set
Impacts on native plants
Focal Plant studies:
36. South Africa s.XIX
Fast clonal growth
Hybrid
8-10 cm pollen rich flowers
Gardening and soil fixation
Carpobrotus aff. acinaciformis
Study species:
37. South Africa s.XIX
Fast clonal growth
Hybrid
8-10 cm pollen rich flowers
Gardening and soil fixation
Carpobrotus aff. acinaciformis
Opuntia stricta
Central America s.XVI
1.5 m high
5 cm pollen rich
flowers
Ornamental
Study species:
38. South Africa s.XIX
Fast clonal growth
Hybrid
8-10 cm pollen rich flowers
Gardening and soil fixation
Carpobrotus aff. acinaciformis
Opuntia stricta
Central America s.XVI
1.5 m high
5 cm pollen rich
flowers
Ornamental
Impatiens glandulifera
Himalayas s.XX
2 m high
Annual
4 cm nectar and
pollen rich flowers
Study species:
39. Breeding system & pollen limitation
Effects on plant-pollinators networks
Invasive pollen transfer to native stigmas!
Combined effects of invasion & landscape
structure
Objectives:
41. Breeding system and pollen limitation
I C
Asexual reproduction
Self compatible
Generalist
Baker(1967)Evolution
42. Breeding system and pollen limitation
New Interactions New Interactions
Parcker and Haubenask (2002)Oecologia
I C
Asexual reproduction
Self compatible
Generalist
Baker(1967)Evolution
43. Study sites:
Breeding system and pollen limitation
Opuntia stricta
Carpobrotus aff. acinaciformis
Suehs et al.(2004)Heredity
I C
44. Study sites:
Breeding system and pollen limitation
Opuntia stricta
Carpobrotus aff. acinaciformis
Suehs et al.(2004)Heredity
I C
45. Study sites:
Breeding system and pollen limitation
Opuntia stricta
Carpobrotus aff. acinaciformis
Suehs et al.(2004)Heredity
I C
46. Kearns & Inouye(1993)
5 Treatments:
Forced out-crossing
Open pollination
Anemogamy
Facilitated self-pollination
Spontaneous self-pollination
40 flowers treatment x 3 site
Breeding system and pollen limitation
I C
47. Breeding system and pollen limitation
I C
Site 1
Site 2
Site 3
Forced
Out-crossing
48. Breeding system and pollen limitation
I C
Site 1
Site 2
Site 3
Forced
Out-crossing
49. Breeding system and pollen limitation
I C
Site 1
Site 2
Site 3
Forced
Out-crossing
50. Breeding system and pollen limitation
I C
Site 1
Site 2
Site 3
Forced
Out-crossing
51. Breeding system and pollen limitation
I C
Site 1
Site 2
Site 3
Forced
Out-crossing
52. Breeding system and pollen limitation
I C
Site 1
Site 2
Site 3
Forced
Out-crossing
53. Breeding system and pollen limitation
I C
Site 1
Site 2
Site 3
Forced
Out-crossing
54. Breeding system and pollen limitation
I C
Site 1
Site 2
Site 3
Forced
Out-crossing
55. Breeding system and pollen limitation
Low self-compatibility They need pollinators
I C
56. Breeding system and pollen limitation
Low self-compatibility They need pollinators
Slightly pollen limited
Hybrid
Coleoptera
I C
57. Breeding system and pollen limitation
Low self-compatibility They need pollinators
Slightly pollen limited
Hybrid
Coleoptera
I C
Efficient pollinators
Xilocopa violacea & Apis mellifera
58. Breeding system and pollen limitation
Low self-compatibility They need pollinators
Slightly pollen limited
Hybrid
Coleoptera
I C
Efficient pollinators
Xilocopa violacea & Apis mellifera
63. Effects on plant-pollination networks
Competition with natives at a community level
Pollinator sharing
Decrease the number of visits to natives
Changes in the community structure
Nestedness
Centrality
Strength
I C
69. Effects on plant-pollination networks
Pollinator species
53 species to natives
23 species to Carpobrotus (42%)
I C
70. Effects on plant-pollination networks
Pollinator species
53 species to natives
23 species to Carpobrotus (42%)
7 Visits natives
Visits
27 Visits Carpobrotus
I C
71. Effects on plant-pollination networks
>70% natives increase nº visits in invaded
plots (GLMM P<0.02)
Pollinator species
53 species to natives
23 species to Carpobrotus (42%)
7 Visits natives
Visits
27 Visits Carpobrotus
I C
73. Effects on plant-pollination networks
19% visits
Xilocopa
violacea
Pollinator species
54 species to natives
17 species to Opuntia (31%)
I C
74. Effects on plant-pollination networks
19% visits
Xilocopa
violacea
Pollinator species
54 species to natives
17 species to Opuntia (31%)
6 Visits natives
Visits
44 Visits Opuntia
I C
75. Effects on plant-pollination networks
>60% natives decrease nº visits in invaded
plots (GLMM P=0.04)
19% visits
Xilocopa
violacea
Pollinator species
54 species to natives
17 species to Opuntia (31%)
6 Visits natives
Visits
44 Visits Opuntia
I C
97. Effects on plant-pollination networks
Opuntia stricta
Plants
Pollinators
j
i
dji = nºVji/nº VjDependence of j on i:
I C
Bascompte et al.(2006)Science
98. Effects on plant-pollination networks
Opuntia stricta
Plants
Pollinators
j
i
dji = nºVji/nº VjDependence of j on i:
Si = ∑ djiStrength of i:
I C
Bascompte et al.(2006)Science
99. Effects on plant-pollination networks
Opuntia stricta
Plants
Pollinators
j
i
SCarpobrotus > Snatives
(6.5) (2.2)
SOpuntia > Snatives
(8.1) (2.1)
Strength
dji = nºVji/nº VjDependence of j on i:
Si = ∑ djiStrength of i:
I C
Bascompte et al.(2006)Science
100. Effects on plant-pollination networks
Both invaders are generalists:
Nº Pollinators
Nº of visits
Position in the network
I C
101. Effects on plant-pollination networks
Different effects on plant comunity:
Increase visits in Carpobrotus plots
Decrease visits in Opuntia plots
I C
102. Invasive pollen transfer to
native stigmas
I C
Bartomeus I, Bosch J & Vilà M (2008) Annals of Botany
106. Invasive pollen transfer to native stigmas
Pollen loads in pollinator bodies
Conspecific pollen
Invasive > heterospecific native pollen
Shared
pollinators
I C
107. Invasive pollen transfer to native stigmas
Pollen loads in pollinator bodies
Conspecific pollen
Invasive > heterospecific native pollen
Pollen deposition in native plant
stigmas
Proportion of invasive pollen
Shared
pollinators
I C
110. Carpobrotus
39% plant cover
36% of visits
Fuchsine stained gelatine
5 Plant species
49% plant cover
51% of visits
10 pollinators
(5 bees, 5 beetles)
76% of visits
Invasive pollen transfer to native stigmas
I C
111. Carpobrotus
39% plant cover
36% of visits
Fuchsine stained gelatine
30 stigmas x
species
15 pollinators x
interaction
5 Plant species
49% plant cover
51% of visits
10 pollinators
(5 bees, 5 beetles)
76% of visits
Invasive pollen transfer to native stigmas
I C
126. 2 pollinators (bees):
Dominant heterospecific > invasive (p < 0.001)
6 pollinators:
Dominant heterospecific ∼ invasive
2 pollinators (beetles):
Invasive > dominant heterospecific (p < 0.006)
Invasive vs. heterospecific native pollen
Invasive pollen transfer to native stigmas
I C
127. 2 pollinators (bees):
Dominant heterospecific > invasive (p < 0.001)
6 pollinators:
Dominant heterospecific ∼ invasive
2 pollinators (beetles):
Invasive > dominant heterospecific (p < 0.006)
Invasive vs. heterospecific native pollen
Invasive pollen transfer to native stigmas
I C
128. All stigmas were covered
by pollen
Average: 2 pollen species
per stigma
Invasive pollen transfer to native stigmas
36% invasive pollen
stigmas
I C
129. All stigmas were covered
by pollen
Average: 2 pollen species
per stigma
Invasive < heterospecific < conspecific (χ2, p < 0.0001)
Invasive pollen transfer to native stigmas
36% invasive pollen
stigmas
I C
132. 1) pollinator
species sharing
3) low invasive
pollen loads
2) effective
pollen transfer
Invasive pollen transfer to native stigmas
I C
133. 1) pollinator
species sharing
4) lower invasive pollen deposition
3) low invasive
pollen loads
2) effective
pollen transfer
Invasive pollen transfer to native stigmas
I C
134. 1) pollinator
species sharing
4) lower invasive pollen deposition
3) low invasive
pollen loads
2) effective
pollen transfer
Invasive pollen transfer to native stigmas
...Floral constancy, morphology & temporal presentation
I C
135. Combined effects of invasion
& landscape structure
I C
Bartomeus I, Vilà M & Setffan-Dewenter I(In preparation)
140. Combined effects of invasion & landscape structure I C
Steffan-Dewenter et al.(2002)Ecology
141. Combined effects of invasion & landscape structure I C
Steffan-Dewenter et al.(2002)Ecology
142. Combined effects of invasion & landscape structure I C
Steffan-Dewenter et al.(2002)Ecology
143. Combined effects of invasion & landscape structure I C
Steffan-Dewenter et al.(2002)Ecology
144. Combined effects of invasion & landscape structure I C
Westphal et al.(2003)Ecol Lett
145. Combined effects of invasion & landscape structure I C
Westphal et al.(2003)Ecol Lett
146. Combined effects of invasion & landscape structure I C
Westphal et al.(2003)Ecol Lett
147. X 14 sites in a landscape gradient
Combined effects of invasion & landscape structure
17% of natural cover71% of natural cover
Grassland
Agricultural fields
Human activity area
Landscape sites at 3000 m radii.
Forest
I C
148. X 14 sites in a landscape gradient
Combined effects of invasion & landscape structure
17% of natural cover71% of natural cover
Grassland
Agricultural fields
Human activity area
Landscape sites at 3000 m radii.
Forest
I C
100m 100m
Before Impatiens flowering period
Raphanus sativus
pots
Impatiens
stands
149. X 14 sites in a landscape gradient
100m 100m
During Impatiens flowering peak
Combined effects of invasion & landscape structure
17% of natural cover71% of natural cover
Grassland
Agricultural fields
Human activity area
Landscape sites at 3000 m radii.
Forest
I C
100m 100m
Before Impatiens flowering period
Raphanus sativus
pots
Impatiens
stands
150. Log (proportion of agricultural land cover)
Log(numberofbumblebeesvisits)
0
1
2
21 1.5
Combined effects of invasion & landscape structure
Before Impatiens flowering
During Impatiens flowering
R2= 0.25; p< 0.003
I C
151. Log (proportion of agricultural land cover)
Log(numberofbumblebeesvisits)
0
1
2
21 1.5
Combined effects of invasion & landscape structure
Before Impatiens flowering
During Impatiens flowering
R2= 0.25; p< 0.003
I C
155. 0
5
10
15
20
25
30
35
40
45
50
% Fruit set
Nº Visits
Raphanus pots
Combined effects of invasion & landscape structure
Before /
Non-invaded
Before /
Invaded
During /
Non-invaded
During /
Invaded
I C
NºVisits/%Fruitset
156. 0
5
10
15
20
25
30
35
40
45
50
% Fruit set
Nº Visits
Raphanus pots
Combined effects of invasion & landscape structure
Before /
Non-invaded
Before /
Invaded
During /
Non-invaded
During /
Invaded
I C
NºVisits/%Fruitset
158. Combined effects of invasion & landscape structure
1) Social bees increase in
agricultural areas before
the invasive plant flowering
2) No effect on wild bees
I C
159. Combined effects of invasion & landscape structure
4) Native plants do not
decrease visitation, nor seed set
3) Impatiens attracts mainly
bumblebees
1) Social bees increase in
agricultural areas before
the invasive plant flowering
2) No effect on wild bees
I C
160. Combined effects of invasion & landscape structure
Impatiens mask off
the landscape effect
4) Native plants do not
decrease visitation, nor seed set
3) Impatiens attracts mainly
bumblebees
1) Social bees increase in
agricultural areas before
the invasive plant flowering
2) No effect on wild bees
I C
168. Take home message
Plant-pollinator networks are complex &
the invasion outcome is difficult to predict.
However, invasive plants cause significant changes
on the networks.
169. Thank you for your attention
And special Thanks to collaborators: Montse Vilà, Jordi
Bosch, Ingolf Steffan-Dewenter; Lab colleges: Jara Andreu,
Nuria Gasso, Salva Blanch, Belén Sanchez and CREAF
friends.