This document summarizes the potential for native bee species to provide pollination in agricultural landscapes in Australia. It discusses how native bees require both foraging habitat with food sources and nesting habitat. Hedgerows can provide valuable foraging habitat for native bees if managed properly with native plantings. The document recommends enhancing hedgerows and minimizing insecticide use to encourage native bee populations and support their potential role in agricultural pollination.

1. Making the most of native bees: hedgerow potential in agri-natural landscapes of
Mediterranean climate
Georgia D. PollardA
A
School of Natural and Built Environments, University of South Australia, Adelaide, Mawson Lakes, 5095, Australia
Corresponding author. Email: georgia.pollard@me.com
Abstract
Although Australia has over 1,500 species of native bee, agriculture depends on the
introduced honeybee, Apis millfera for pollination. Pests and diseases that are likely
to reach Australia are currently decimating honeybee populations worldwide. Native
bees can meet pollination requirements if sufficient support is given. Hedgerows
when managed properly can provide valuable foraging habitat and a shift in
pollination dependency to native bee species is both practical and viable.
Introduction
Pollination is an essential ecosystem service. Honeybees, Apis millfera are the most
important managed pollinator in the world (Southwick and Southwick 1992) and can
enhance agricultural seed production and yield (Moradin and Winston 2006). In
Australia we depend on the introduced honeybee for honey and agricultural
pollination (Dollin et al. 2000). The honeybee is experiencing crisis in other parts of
the world because of pests such as the varroa mite, Varroa destructor, diseases like
Colony Collapse Disorder and insecticide use. Any one of these reaching Australia
will cause problems to industries dependant on honeybees, as in the US and Germany
(Cunningham et al. 2000). A solution entails changes in agricultural practise to
include use of native bees. Native bees require supportive foraging habitat, such as
1

2. hedgerows. In this review, ‘hedgerow‘ is defined as, “a linear vegetation feature,
including field margins, windbreaks and roadsides” and ‘agri-natural landscapes’ as,
“land consisting of agricultural use and natural vegetation.” The potential for use and
management of native bees in agri-natural landscapes such as the Yorke Peninsula is
examined.
Native bee requirements
Australia has over 1,500 species of native bee, which have adapted to every type of
habitat available (Dollin et al. 2000). In South Australia there are many species of
mining bee, mainly Colletines and Halictines (Edwards 2010). All bees require
sources of pollen, nectar, floral oils, nest sites and nesting material to live (Westrich
1996; Hannon and Sisk 2009). Bee habitats can be separated into partial habitats of
either foraging or nesting habitat. They can be separate areas within a larger
landscape (Westrich 1996; Kleijn et al. 2006; Hopwood 2008; Smallbone and
Spooner 2008; Hannon and Sisk 2009).
A study from Western USA found that the understorey vegetation is most
important when assessing whether the foraging habitat is resource rich or poor
(Hannon and Sisk 2009). Native plants are beneficial and tend to attract higher
abundance and variety of bee species (Kremen et al. 2002; Hopwood 2008; Edwards
2010), but flowering crops also make suitable foraging habitat (Heard 1999) when
insecticides do not affect bee numbers (Steffan-Dewenter and Tsharntke 1999;
Kremen et al. 2002; Moradin and Winston 2006; Hannon and Sisk 2009). The mining
species of native bee common to South Australia require nest sites that are open to the
sun but somewhat sheltered with vegetation cover not exceeding 50% (Edwards
2010). Both kinds of partial habitats can be provided in agri-natural landscapes under
2

3. the right circumstances (Westrich 1996; Kremen et al. 2002; Kleijn et al. 2006;
Moradin and Winston 2006; Hopwood 2008; Hannon and Sisk 2009; Edwards 2010).
Hedgerow value
When comparing hedgerow value to remnant native vegetation there is some debate
(Westrich 1996). Although remnant vegetation may provide a wider variety of
resources, the avaliability of such vegetation must be considered. Ninety four percent
of Yorke Peninsulas native vegetation had been clear by 1989 (Malcolm and Wigan
1989). For mining bees, hedgerows do tend to be more heavily vegetated than is
suitable for nest sites but hedgerows can be valuable foraging habitat if the
understorey is rich in flowering shrubs and native ground cover (Westrich 1996;
Kremen et al. 2002; Hopwood 2008; Edwards 2010). Such hedgerows could link the
remnants left and help reduce the chance of regional extinction of surviving native
bee species (Westrich 1996). Hedgerows regulate surrounding air temperature, soil
water content and organic carbon (Bunce et al. 2009) as well as being beneficial to
other species such as birds and small mammals (Campi and MacNally 2001; Gelling
et al. 2007).
Viability of agricultural pollination by native bees
Bees provide pollination services in both natural and agricultural environments
(Heard 1999; Steffan-Dewenter and Tscharntke 1999; Kremen et al. 2002; Kleijn et
al. 2006; Moradin and Winston 2006; Hannon and Sisk 2009; Edwards 2010) and
enhance seed production and yield (Steffan-Dewwenter and Tsharntke 1999; Kremen
et al. 2002; Moradin and Winston 2006). The distance bees can fly for pollen
collection is positively correlated with body size (Steffan-Dewwenter and Tsharntke
3

4. 1999) unless nectar is available along the way (Westrich 1996). Native mining bees
have been reported travelling an average of 500 m for pollen, although one hive was
spotted in the centre of a canola field in South Australia (Edwards 2010). Having 30
% of uncultivated land within 750 m from field edges maximized crop yield and
profit (Moradin and Winston 2006).
Full pollination requirements were met by just native bees on organically
managed farms near natural habitat in California, but they were insufficient on non-
organic farms, with extensive use of insecticides and lack of supplementary habitat
detrimental to the bees (Moradin and Winston 2006). Although the main crops grown
on the Yorke Peninsula are wheat and barley and so wind pollinated, other crops
grown there including canola, peas, lentils, beans, sunflowers and tomatoes would
benefit from bee pollination (Heard 1999; Steffan-Dewwenter and Tsharntke 1999;
Cunningham et al. 2000; Kremen et al. 2002; Moradin and Winston 2006).
Practical support of native bees in agri-natural landscapes
Recommendations on how to provide nesting habitat for native bees have been made
in a study from England (Kleijn et al. 2006), by widening field edges to 6 m or by
identifying small linear areas to be set aside from production for at least three years
with at least one such area per square kilometre (Edwards 2010). This land is suitable
as nesting habitat for mining bees.
Supplementary foraging habitat needs to be available when crops are not
flowering (Kremen et al. 2002). Managed hedgerows along field edges and roadsides
close to fields, with understoreys of native shrubs and ground flora would provide
rich foraging habitat (Kremen et al. 2002; Hannon and Sisk 2009; Edwards 2010).
Fields retired from crop production but still being used as grazing land result in poor
4

5. foraging habitat (Hannon and Sisk 2009) but I did not find studies on the impacts of
grazing on nest habitats of native mining bees.
Extensive use of insecticides on fields adversely affects visiting bees.
Lessening their use and enhancing hedgerows can also increase abundance of other
beneficial insects (Kremen et al. 2002). To gain the full benefits from native bee
pollinators, the enhancement of foraging habitat and creation of nest habitats, as well
as minimised use of insecticides are recommended (Kremen et al. 2002; Hannon and
Sisk 2009; Edwards 2010).
Conclusion
Pests and diseases such as Colony Collapse Disorder or the varroa mite, reaching
Australia, are likely to have adverse effects our honeybee populations. A shift in
reliance on species of native bee for agricultural pollination is suggested as both
possible and viable (Cunningham et al. 2000) because bees have the potential to
compliment or meet the full pollination requirements of agricultural crops (Kremen et
al. 2002). Agriculture on the Yorke Peninsula can mitigate the risk of agricultural
pollination loss by changes to agricultural practise to encourage growth of native bee
species by implementing nesting and foraging habitats within hedgerows and field
edges.
References
5

6. Bunce, R. G. H., Lassaletta, L., McCollin, D., and Sanchez, I. A. (2009). The effect of
hedgerow loss on microclimate in the Mediterranean region: an investigation in
Central Spain. Agroforestry Systems 78, 13-25. doi:10.1007/s10457-099-9224-z
Campi, M. J., and MacNally, R. (2001). Birds on edge: avian assemblages along
forest-agricultural boundaries of central Victoria, Australia. Animal Conservation
4, 121-132.
Cunningham, S. A., FitzGibbon, F., and Heard, T. A. (2000) The future of pollinators
for Australian agriculture. Australian Journal of Agricultural Research 53, 893-
900.
Dollin, A., Batley, M., Robinson, M., and Faulkner, B. (2000). Native bees of the
Sydney region. Australian Native Bee Research Centre.
http://www.aussiebee.com.au/fieldguide.html Accessed; April 2nd 2011.
Gelling, M., MacDonald, D. W., and Mathews, F. (2007). Are hedgerows the route to
increased farmland small mammal density? Use of hedgerows in British pastoral
habitats. Landscape Ecology 22, 1019-1032.
Edwards, M. (2010). Draft report – Assessment of native pollinators of crops in South
Australia. (NRM: South Australia.)
Hannon, L. E., and Sisk, T. D. (2009). Hedgerows in an agri-cultural landscape:
Potential habitat value for native bees. Biological Conservation 142, 2140-2154.
Heard, T. A. (1999). The role of stingless bees in crop pollination. Annual Review of
Entomology 44, 186-206.
Hopwood, L. J. (2008). The contribution of roadside grassland restorations to native
bee conservation. Biological Conservation 141, 2632-2640.
6

7. Kleijn, D., Marshall, E. J. P., and West, T. M. (2006). Impacts of an agri-environment
field margin prescription on the flora and fauna of arable farmland in different
landscapes. Agriculture, Ecosystems & Environment 113, 36-44.
Kremen, C., Thorp, R. W., and Williams, N. M. (2002). Crop pollination from native
bees at risk from agricultural intensification. Proceedings of the National
Academy of Sciences of the United States of America 99, 16812-16816.
Malcolm, I., and Wigan, A. (1989). Report to Yorke Peninsula roadside vegetation
steering group on roadside management plans for Yorke Peninsula.
Morandin, L. A., and Winston, M. L. (2006). Pollinators provide economic incentive
to preserve natural land in agroecosystems. Agriculture, Ecosystems &
Environment 116, 289-292.
Smallbone, L., and Spooner, P. G. (2008). Effects of road age on the structure of
roadside vegetation in south-eastern Australia. Agriculture, Ecosystems &
Environment 129, 57-64.
Steffan-Dewenter, I., and Tscharntke, T. (1999). Effects of habitat isolation on
pollinator communities and seed set. Oecologia 121, 432-440.
Westrich, P. (1996). Habitat requirements of central European bees and the problems
of partial habitats. The conservation of Bees 1-6.
7