dc.identifier.citation |
Raju, A.J.S. (2018). "Climate Change: Impacts on Plant-Pollinator Interactions", Proceedings of the 23rd International Forestry and Environment Symposium 2018 of the Department of Forestry and
Environmental Science, University of Sri Jayewardenepura, Citrus Waskaduwa, Waskaduwa, Sri Lanka, 3 p. |
en_US |
dc.description.abstract |
For plant reproduction, timing of phenological events is important. Flowering phenology is a key event in
enabling the pollinators to visit and pollinate the flowers. In this process, most of the flowering plants
and pollinators are co-evolved. Pollination is the key event for plants to set fruit and for the pollinators to
get their food. Flowering phenology is affected by many environmental factors, among which temperature
and photoperiod are reliable signals of seasons. Any shift in the timing of flowering phenology is bound
to impact the foraging activities of pollinators. In effect, the mismatch between the flowering time and the
flight time of insects would lead to disruption of the pollination process. Further, plants with insufficient
material resources if flower too early will have a limited capacity for seed production while those that
delay flowering might gain higher capacity, but might also run out of time to use it prior to the end of the
season. Therefore, resources and conditions impose bottom-up selective forces on flowering phenology.
Several workers outside India have shown that climate change due to global warming is affecting
pollination by disrupting the synchronised timing of flowering and the timing at which pollinators
pollinate. In effect, the plants bloom early or delay flowering due to rising temperatures; such shifts in
flowering time would severely impact their sexual reproduction due to mismatch of their flowering
timings with the timing of foraging activities of their pollinators. In case of fruit, vegetable, seed, nut and
oil crops which are sources of vitamins and minerals, if the pollination rate is limited or ceased to happen,
the world will witness increasing risk of malnutrition. The responses of individual species of pollinators
to shifts in flowering timings vary but they are almost unknown. If there is no shift in timing by
pollinators, there could be a severe decline in pollination and a lack of food sources for them. Plants also
end up with pollination limitation or failure due to which sexual production gets severely impacted.
Recent reports indicate that the climate change is interfering with plant-pollinator mutualism, an
interaction facilitated largely by floral colour and scent. Floral scent production decreases with an
increase in ambient temperature; in effect a significant decrease in the emission of scent compounds
occurs. This drop in floral scent production is the result of arrested expression and activity of proteins
that help in the biosynthesis of the compounds. Floral scent provides a sensory signal to pollinators and
drop in floral scent production could make them less attractive to pollinators. Floral colours provide a
visual signal to pollinators and shifts or change in their colour would affect the visitation by pollinators.
Increase in ambient temperature could cause early fading or shift in floral colour and thus affecting the
pollination rate by pollinators. Elevated temperatures affect the physiology of flowering plants due to
which production rate of flowers, nectar and pollen is altered. Warming temperatures influence foraging
activity, body size at maturity, as well as the individual life span of insect pollinators. Insect larvae
mature into adults sooner, some bird species lay eggs earlier in the season, and many plants bloom earlier.
In addition to advancing many phenological events, climate warming is altering the distributions of both
plant and pollinator species. Climate change also brings about positive effects for certain plant and
pollinator species. Increased ambient temperature enables some plant species to proliferate well and
some other plant species to be invasive and occupy new habitats across latitudes, longitudes and altitudes.
Similarly, some pollinator species such as stingless bees multiply and produce numerous colonies,
especially in urban settings where warm conditions exist. Therefore, pollination biologists have a
tremendous challenge to understand how climate change might affect plant-pollinator interactions, and
reveal the importance of climate warming relative to other human modifications of natural habitats for the
persistence and stability of these interactions. This insight could enable us to better understand how
community properties and biodiversity in different ecosystems may change by climate-driven plantpollinator
mismatches. |
en_US |