POLLINATORS POLLINATION AND FOOD PRODUCTION

THE ASSESSMENT REPORT ON POLLINATORS, POLLINATION AND FOOD PRODUCTION
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6. RESPONSES TO RISKS AND OPPORTUNITIES ASSOCIATED
WITH POLLINATORS AND POLLINATION
nature conservation strategies in protecting the pollinators
of NTFPs.
6.4.3.1.4 Invasive species
Where non-native insect pollinators pose a threat to the
native fauna (see Chapter 2, section 2.5), management of
invasive species is likely to be an important component of
a pollinator conservation strategy. However, eradication of
invasive species has proven difficult in most circumstances,
with successful eradication most often occurring on islands
where the area to manage is limited, and re-invasion is less
likely. Because of this challenge, studies of the effectiveness
of invader management in terms of pollinator response are
rare. Nagamitsu et al. (2010) showed that active removal of
Bombus terrestris from sites in Japan allowed an increase
in abundance of queens for two native Bombus species,
but attempts to reduce Bombus terrestris numbers in the
next year failed. Hanna et al. (2013) show that a reduction
in invasive wasps (using poison baits) led to an increase
in pollination and subsequent fruit set of a native plant
in Hawaii, although interestingly in this case the primary
pollinator was also an invasive species (Apis mellifera).
Because it is so difficult to eradicate invasive species, a
focus on mitigating their impact can be the necessary
alternative. There have been many examples where
management has successfully contained or reduced
populations of invasive species, reducing their impact (Mack
et al., 2000).
6.4.3.1.5 Species-focused conservation actions
Butterflies have often been a target group for speciesfocused
conservation actions (New et al., 1995) with
a number of successful projects (e.g., Thomas et al.,
2009) including ex situ conservation (Schultz et al.,
2008). Although they have had a high profile in species
conservation, relative to other insects, butterflies are
considered minor pollinators relative to other insect groups,
especially bees (Chapter 1). One group of wild bees has
been a focus for nature conservation: the bumble bees
(Bombus spp.). This reflects that bumble bees are large and
distinctive, and some species have experienced significant
declines in parts of Europe, Japan, and the Americas
(Williams and Osborne, 2009). Generalising from Bombus
to other species should be done with caution, but these
studies provide a starting point for understanding the
potential for species-focused conservation actions.
Most on-ground strategies for species conservation are
essentially forms of habitat management (and are therefore
discussed above), albeit that some habitat interventions can
be more precisely targeted if single species are the focus.
For example, nest preferences are quite specific, and so
provision of nest resources should match the preferences
of the species of concern. Beyond habitat management,
conservation strategies for single species might also include
ex situ conservation and species re-locations. For example,
Bombus subterraneus has been extirpated from its original
range in the UK, but still occurs on the European mainland
and in its introduced range in New Zealand. A project has
been established to restore the required habitat and then
reintroduce bees (http://hymettus.org.uk/downloads/B_
subterraneus_Project_report_2011.pdf accessed
September 5 2014). Bees were released in 2012 and are still
being sighted in 2014 (http://www.bumblebeereintroduction.
org/news/news/ accessed September 5 2014).
Wild Apis species in Asia, such as Apis dorsata, have also
been subject of special attention. There is a long history of
traditional exploitation of these species for their honey, and
as a consequence they have particular cultural significance
and are the subject of traditional knowledge. Use of
traditional techniques to create good nesting locations might
help support their populations (Hadisoesilo, 2001).
We could find no reports of other active ex situ conservation
actions that were specifically pollinator targeted, although
some vertebrate pollinator species (especially birds and
bats) that are endangered in their native range are held in
captive populations in zoos and other institutions (e.g., the
Rodrigues Fruit Bat, Pteropus rodricensis, O’Brien et al.,
2007). Fruit bats are the primary pollinators of some plants
on Pacific Islands but are hunted for meat and threatened
by hunting and invasive species (Cox and Elmqvist,
2000). Captive populations may contribute to species reintroductions
if the drivers of threat can be managed in the
natural range.
Translocation of species into new locations, where they
may have a better chance of survival, has been suggested
as a strategy that might be increasingly called for under
climate change (Seddon et al., 2014) and has recently
been suggested for bumble bees in particular (Kerr et al.,
2015). This strategy might also have the effect of restoring
ecological function to locations that have lost species. The
number of case studies for the practice of translocation
is a rapidly increasing and therefore helping to reveal the
logistic challenges of the strategy (Seddon et al., 2014). The
knowledge base for translocation of pollinators in particular
is poor because insects, the most important group of
pollinators, are rarely the subject of translocations (most
cases focus on birds and mammals: Seddon et al., 2014).
Nevertheless there have been successful translocations of
some butterfly species (Kuussaari et al., 2015) and among
the important lessons is that there must be high-quality
suitable habitat available in the new location. Translocation
comes with considerable risk of failure to establish and
could also lead to unintended harm if translocated species
become invasive pests or vectors for disease in the new
range (Seddon et al., 2014 and see section 6.4.3.1.4.