Once upon a time

Hedges are disappearing. Where do the birds, insects rest?

By Sharmila Kher
Last Updated: Saturday 04 July 2015

Pollinators are overworked these dayshabitat fragmentation has increased the distance between members of the same plant species leaving them isolated from their pollinators. As a result plant population sizes are decreasing. Current agricultural practices, specifially single crop farming, are to blame.

When only one type of crop is grown in a farm, it does away with buffer strips where other plants are grown for fencing between different types of crops. These plants are quality pollinator habitats.

Large farmlands as found in the western countries are located too far away from each other. There is an increased distance between stopover points and with the absence of ditches and hedges in between farms, pollinators like insects and small birds suffer. They cannot fly long distances nonstop. Called linear landscape elements (lles), these ditches, hedges act as biological corridors to rescue pollinators.With an ever-increasing demand for land, the lles are reducing in number.

Researchers from the Plant Biology and Nature Management Institute in Belgiun studied the pollination of the rapidly declining evening primrose (Primula vulgaris) by bees, butterflies, moths. Earlier it was assumed that pollinators use the lles to rest or build nests but the extent of their importance was proved by this experiment.

Dyes, acting as pollen substitutes, were applied to stamens of plants, some of which had lles separating them, others did not. After four days it was observed that the dye was dispersed faster and longer distances in populations connected by trees and hedges in between. The findings were published by the Journal of Ecology in November.

In India wild varieties are often allowed to grow between mixed crops which is the prevalent method of agriculture. Natural corridors are a part of the Indian farming landscape; trees on roadsides and hardy ruderals (species that grow on poor soil) are plenty allowing pollinators to rest, said Aparna Watve, botanist from Madhya Pradesh.

Parthib Basu, a pollination researcher, said India is suffering from pollination crisis and studies are on to quantify the loss of ecosystem services due to it: Our agricultural landscapes would be interspersed with small hedges at one time. They have disappeared due to increasing demand for land.

It is important to understand the role of the corridors for better agriculture management. Sacred Groves exist in several parts of India and are a natural refuge for pollinators, said Basu.

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