Honey
bees are experiencing severe declines which are not yet resolved, and
remain a
concern to crop growers, beekeepers, and the public.
Terrestrial ecologists are also concerned
about loss of pollinators and impacts of urbanization, climate and land
use/cover change on the crucial ecosystem process of pollination, a
complex
evolved interaction of plants and animals with likely differing
individual
responses to change. It is difficult to
relate variations in plant-pollinator interaction to climate change on
the 1-5
km scales of satellite climate records (e.g. MODIS, NPP VIIRS) and
biosphere-climate
models, because very little quantitative data exist to develop
necessary
linkages and general parameterizations.
Metrics of the timing of nectar flows, using honey bees as
samplers and
derived from daily weighing of honey bee colonies (scale-hive records),
appear
to be quite useful. A 15 year time
series indicates that the nectar flow in central MD occurs nearly a
month
earlier today than in historical records.
Earlier nectar flows (pollination periods) may have noticeable
impact on
local ecosystems, and on the availability of local honey bee colonies
of
sufficient strength for spring pollination.
In 2007 a local volunteer scale hive network at 14 different
sites
confirmed this advance, and demonstrated potential for more extensive
surveys
of nectar flows. In central MD, the nectar
flow is closely associated with the time of spring green-up seen in the
satellite data, and is consistent with increases in local winter
temperatures
due to urbanization and warming, and with earlier blooming dates of
major
nectar plants. Nectar flows often occur
later in the season in other biogeographic regions, for which different
relations to the satellite data records must be developed.
A web site has been established (http://honeybeenet.gsfc.nasa.gov)
to facilitate collection of scale-hive data and satellite comparisons. There is widespread supporting interest in
surveying nectar flows using this approach within the apicultural and
ecological communities.