Abstract
There is growing concern that the global decline of insect pollinators will adversely influence
the stability of pollination in agricultural and terrestrial ecosystems. By enhancing habitat
heterogeneity and ecological connectivity, riparian buffer strips have the potential to promote insect
pollinators in intensively managed landscapes. Insect pollinators and flowering plants were
investigated on a range of riparian margins, and their adjacent grassland fields, to determine the main
physical and botanical attributes driving pollinator diversity.
Irrespective of whether they were fenced or not, riparian margins had richer plant assemblages and
supported more pollinators than grassland fields. While the erection of fences did not enhance the
richness or diversity of flowers, fenced riparian buffer strips supported more even and diverse
assemblages of bumblebees and a greater number of butterflies than unfenced riparian margins. More
bumblebees and butterflies were recorded in wide buffer strips (i.e. over 5 m wide) than in unfenced
margins or narrow buffer strips (i.e. ≤ 3.5 m wide) and butterfly assemblages in wide buffer strips
were richer and more diverse. There was a strong positive relationship between floral resources and
the abundance, richness and diversity of bumblebee and butterfly assemblages. Pollinators only
foraged on a small number of the flower species present and impacts of fencing and buffer strip width
could not solely be attributed to the area and/or species richness of flowers.
Fenced riparian buffer strips, particularly when over 5 m wide, have the potential to provide resources
for insect pollinators in intensively grazed systems. Management to enhance floristic diversity (to
provide a more continuous supply of pollen and nectar) and tussock forming grasses (to provide
shelter for pollinators and nesting locations for bumblebees) could further increase their value to
insect pollinators. In grassland systems, restricted grazing is easier to implement than mowing. It is,
however, important that grazing management does not unduly interfere with other ecosystem services
derived from riparian buffer strips (e.g. diffuse pollution mitigation). Widespread fencing of
watercourses at the catchment level could result in the simplification of these inherently dynamic and
complex habitats. Buffer strips should therefore be strategically placed to optimise benefits such as
ecological connectivity and diffuse pollution mitigation.
Original language | English |
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Pages (from-to) | 207 - 220 |
Number of pages | 14 |
Journal | Agriculture, Ecosystems and Environment |
Volume | 211 |
Early online date | 13 Jul 2015 |
DOIs | |
Publication status | Print publication - 15 Dec 2015 |
Bibliographical note
10233171020905