Statement of research interests and experience
My main research interests are pollination biology, pollinator
conservation and plant-pollinator interactions. I am particularly
interested in pollinator behaviour and how this can affect plant
reproductive success. My PhD investigated the relationship between
pollinators and plants at the landscape scale. The mobility of pollinating
animals is a key feature of their importance but we are largely
ignorant of how landscape structure influences pollinator movements,
though it is known to affect movements of non-pollinating invertebrates.
My fieldwork involved observing the influences of landscape structure
(both natural and artificially created) on insect movement. The
results show that both hedgerows and artificial linear landscape
features can influence the flight directions of bumblebees ( Bombus
spp. Hymenoptera, Apidae), one of Europe's most important
groups of pollinators. Bumblebees follow hedgerows around the landscape.
A bioassay experiment in which Salvia pratensis (Lamiaceae)
was planted into landscape patches with different numbers of connecting
hedgerows showed that this directional response can have a profound
effect on plant reproductive success – plants had increased pollinator
activity, pollen receipt and subsequent seed set in patches with
more connections. I concluded that the overall hedgerow connectedness
of a landscape is therefore important both to bumblebee movement
and to those plants which depend on bumblebees for pollination services.
My postdoctoral work investigated the true pollinators of three
endemic, threatened bird pollinated plants on Tenerife in the Canary
Islands. Previous work had suggested that these plants evolved floral
traits as adaptations to pollination by flower specialist sunbirds,
but there are no specialist flower-visiting birds on the Canary
Islands. The previously undisputed theory stated that these ‘orphaned'
plants subsequently appear to have co-opted passerine birds as sub-optimal
pollinators following the sunbirds' ‘disappearance'. To test these
ideas I carried out a quantitative study of the pollination biology
of three of the bird pollinated plants, Canarina canariensis
(Campanulaceae), Isoplexis canariensis (Veronicaceae)
and Lotus berthelotii (Fabaceae). My fieldwork showed
that the passerine chiff chaff ( Phylloscopus collybita )
was an effective pollinator of these species. The plants have become
well adapted to pollination by these generalist birds that only
occasionally visit flowers. In particular, the large nectar standing
crop and extended flower longevities of Canarina and Isoplexis
strongly suggest that they have evolved a “sit and wait” functionally
specialised passerine bird pollination system, that effectively
exploits these pollen vectors and is in no way suboptimum.
Other interests were inspired by my MSc in insect pest ecology,
particularly biological control and glasshouse integrated pest management.
I have always been fascinated by the array of complementary methods
employed to manage pest numbers. Simple observation and knowledge
of the pest's life cycle can highlight areas in which to target
the pest most effectively rather than the blanket application of
PhD Abstract: ‘The influence of linear landscape features
on pollinator behaviour.'
Linear landscape features such as hedgerows are important wildlife
habitats, but their functional role in improving connectivity in
fragmented habitats remains uncertain. This thesis studied the influence
of both natural and artificial linear features on pollinator behaviour
at medium and landscape scales. Observations along 30m transects,
perpendicular to eight different hedgerows revealed that non-foraging
pollinators were far more likely to exhibit linear flight next to
the hedgerow than they were further out in the field. Using a medium-scale
experimental design, three patches of potted Phacelia tanacetifolia
(Hydrophyllaceae) were arranged equidistantly, with two of the patches
connected by an artificial linear feature. Results demonstrated
that there was significantly greater inter-patch movement by bumblebees
( Bombus spp.) between the connected patches than to the isolated
patch even after the position of the feature was changed. The isolated
patch was not approached from the other two patches. Bumblebees
demonstrated high patch fidelity but their abundance in the connected
patches was not necessarily greater than the isolated patch. There
were no significant differences in hoverfly (Syrphidae) abundance
between patches. Later, the same experimental array was scaled up
to fit within the farm landscape structure, using an existing hedgerow
as the connection. A similar pattern of flight directions emerged.
In a landscape investigation, the reproductive success of Salvia
pratensis (Labiatae) growing in patches with a high number of
connecting hedgerows was compared with those plants growing within
poorly connected patches. Pollinator abundance, pollen grains per
stigma and seed yield, were greater in highly connected patches
compared with patches with fewer connecting hedgerows. The overall
connectedness of a landscape may therefore be important to both
pollinator movement and those plants which depend on them for greater
reproductive success. Linear landscape features might also represent
navigational aids with which pollinators orient themselves.
2005 – Present: I have recently been working in a variety of part
time projects: 1) Wildlife Surveyor - a private commission to conduct
a wildlife survey of private residents' communal gardens in Southampton.
2) Teaching and fieldwork assistant to undergraduate students at
the University of Northampton.
January 2005-July 2005 Postdoctoral Research Assistant
. Queen Mary College, University of London. Awarded a £30,000
NERC-funded grant with Prof. Lars Chittka and Dr Jeff Ollerton to
investigate the pollination of Canary Island endemic plants, involving
three months of fieldwork in the Anaga Mountains of Tenerife.
1999-2004 PhD . ‘The influence of linear landscape
features on pollinator behaviour.' University of Northampton, Landscape
and Biodiversity Research Group. Supervisors: Dr Jeff Ollerton and
Dr Duncan McCollin.
1997-1998 MSc & DIC . Applied Entomology (Insect
Imperial College of Science, Technology and Medicine, London, Silwood
Park Campus. MSc Project: ‘The impact of a localised
insecticide application on the leaf-eating beetle Phratora vulgatissima
(Chrysomelidae) and non-target species within short rotation
coppice willow crops.' In collaboration with the Game Conservancy
1994-1997 BSc (Hons) 2:1. Environmental Biology.
Oxford Brookes University. BSc (Hons) Project: ‘The
abundance and diversity of surface-active invertebrates in differing
habitats with particular reference to ground beetles (Carabidae).'
McCollin, D. & Ollerton, J. (2011) Landscape structure influences
pollinator movements and directly affects plant reproductive success.
Oikos (pdf 640)
J; Johnson , SD ; Cranmer, L & Kellie, S (2003).
The pollination ecology of an assemblage of grassland asclepiads
in South Africa. Annals of Botany , 92 ,
807-834. (Acrobat 1MB)
J & Cranmer, L (2002). Latitudinal trends
in plant-pollinator interactions: are tropical plants more specialised?
Oikos , 98 , 340-350. (Acrobat 131KB)
Cranmer, L ; Ollerton, J & McCollin, D (in
prep.) Landscape structure directly affects bumblebee movements
and plant reproductive success. To be submitted to Oikos .
J., Cranmer, L., Stelzer, R., Sullivan, S. and Chittka, L.
(2008) Bird pollination of Canary Island endemic plants. Naturwissenschaften
(Acrobat 291KB) DOI: 10.1007/s00114-008-0467-8
Ollerton, J; Cranmer, L ; Henderson, B & Gopaul,
D (in prep.) Species richness and pollination ecology of Apocynaceae
s.I. across a savannah-rainforest ecotone in Guyana .
To be submitted to Annals of Botany .
Ollerton, J; Alarcon, R; Waser, N; Price, M; Watts, S; Cranmer,
L ; Hingston, A; Peter, C & Rotenberry, J (in press). A global
test of the pollination syndrome hypothesis. Annals of Botany.