Networks Oregon State University EcoInformatic Summer Institute 2013 Noelle Patterson Introduction Pollination Networks A representation of the complex web of interactions between two distinct groups plants and pollinators ID: 549137
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Slide1
Invasive Plant-Pollinator Dynamics in Meadow
Networks
Oregon State University
EcoInformatic
Summer Institute 2013
Noelle PattersonSlide2
Introduction
Pollination Networks: A representation of the complex web of interactions between two distinct groups: plants and pollinators.
Pollination networks were studied in fifteen
montane
meadows in the HJ Andrews Experimental Forest region.
Pollination networks here include both
native
and
invasive
species.
Common invasive insect:
Apis
mellifera
(European honeybee)
Common invasive plant:
Hypericum
perforatum
(St. John’s
wort
)Slide3
Study #1
Comparison of nonnative
Apis
mellifera and native Bombylius major
Apis
mellifera on Gilia capitata
Bombylius
majorSlide4
-
Apis
mellifera interactions reflect logistic growth. The %50 line corresponds with a G. capitata stem count of 333.6.
-92.1% of Bombylius major interactions were with Gilia capitata
; this is modeled in logistic regression poorly.Slide5
-In terms of
Gilia
capitata use, both Apis and Bombylius occupy the same niche.-However,
Apis mellifera pollinate in much higher numbers and have a broader overall diet than Bombylius
.Slide6
Why so many honeybees?
Apis
mellifera
are a domesticated species whose population is supported by outside human help, giving them an advantage over competition.But-
Bombylius major is a parasite of solitary ground nesting bees.Outside Apis mellifera
impacts… harmful or beneficial?Slide7
Study #2
Hypericum
perforatum and Bombus species
Hypericum
perforatum (St. John’s wort) is a weedy plant native to Europe, W. Asia, and N. Africa which has become invasive in many areas including the Western Cascades.Although many nonnative plants in the HJA are restricted to roadsides, H. perforatum was found in three meadows from the 2011 sites.
H.
perforatum
is a popular food source for bumblebees in the late summer season. Slide8
A strong correlation exists between the amount of H.
perforatum
in the meadows and the proportion of pollination visits
Bombus made to H. perforatum.
Point: Bombus species appear to have a preference for invasive Hypericum
perforatumSlide9
Good news:
the variety of
Bombus
plant partners does not decrease due to H. perforatum presence.
The percentage of available flower species pollinated by Bombus is found in each round as an average of meadows with H. perforatum
and neighboring meadows without H. perforatum. Slide10
Bumblebees: following the flower?
During rounds 4 and 5 when H.
perforatum
is abundant, significantly more Bombus are found in meadows containing or nearby H.
perforatum.Slide11Slide12Slide13Slide14Slide15
Conclusion
Invasive species such as
Apis
mellifera and
Hypericum perforatum have important roles within the pollination networks at the HJ Andrews forest.Apis
mellifera is an important pollinator, but its volume of interactions may present competition to insects with overlapping niches like Bombylius major.Hypericum
perforatum has become an significant part of late season Bombus diets and could affect their distribution and where they winter over.Much work must still be done exploring the relationships between insects, plants, and the entire network to gain a better understanding of these rich ecosystems.Slide16
Thank you
To the EISI mentors who made this summer possible and to my great pollinator crew!