|
The effects of honeybees (Apis mellifera) and
nectar robbing flower visitors on hummingbird-plant interactions
in south-eastern Peru.
Introduction
Recently a number of researchers have pointed to a global pollination
crisis. Some authors have reported declines in many pollinator groups,
including indigenous birds, bats and insects, and the plant guilds
that support them (Kearns and Inouye 1997, Allen-Wardell et al,
1998, Corbet 2000, Kremen and Ricketts, 2000 and Roubik 2000). In
the Neotropics, the colonisation by African honeybees (Apis mellifera)
has been cited as a possible threat to native plants and their associated
pollinators. Honeybees interact with approximately one-fourth of
the flora and many of the flower visitors in Tropical America. The
possible dangers of honeybees to native pollinators and their plants
has been highlighted in the past by Roubik, 1978; Paton, 1993; Leide
1994; Ollerton and Leide, 1997. There is now growing concern that
failure to confront the declines in populations of animals providing
pollination services could have major implications for the pollination
of both wild plant communities and agricultural crops (Allen-Wardell,
et al, 1998).
Invasive animal species such as honeybees cause pollinator disruptions
by displacing native fauna from plants without effecting comparable
pollination (Roubik 2000). In Australia, European honeybees remove
pollen from some bird-pollinated plant species, thereby reducing
the amount of pollen that nectarivorous birds would subsequently
deposit on flowers. In some cases honeybees exacerbate pollination
disruption by nectar robbing floral resources. Additionally, a reduction
in territories and the number of birds living in a patch has been
reported when honeybees were present (Paton, 1993). However, we
do not know if the same is true for Neotropical plants and their
hummingbird pollinators.
In Peru, work on the effects of possible disruptions from honeybees
on the native hummingbird fauna and other flower visitors is non-existent.
The Urubamba Valley, Department of Cusco, have high floristic and
faunal diversity and include patches of South America's most endangered
forest ecosystem-Polylepis. The region has been identified as a
key area for endemic and threatened birds (Stattersfield et al,
1998; Wege and Long, 1995. Sixteen species of birds have been listed
in the IUCN red data book and are considered endangered. The following
species of endemic hummingbirds are of particular interest to this
study: Oreonimpha noblis, Chalcostigma olivaceum, and Aglaeactis
castelnaudii.
Objectives
The aims of this research are to build on earlier fieldwork undertaken
on hummingbird-plant interactions in Peru during 1998-2000.
The objectives of this project are to:
- Understand the relative importance of hummingbirds, native
insects and honeybees as pollinators of native plants.
- Document the extent to which honeybees displace hummingbirds
from plants which are normally hummingbird pollinated.
- Assess the vulnerability of hummingbird-plant interactions
to disruption by honeybees and other flower visitors.
- Make recommendations for sustaining, or restoring pollination
systems.
- Establish a long-term monitoring programme (in collaboration
with Cusco University), to continue after the project has finished,
and assess any changes in diversity and abundance of pollinators.
[Top]
|
