The hedges are disappearing

Habitat 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, specifically 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 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. Researchers from the Plant Biology and Nature Management Institute in Belgium studied the pollination of the rapidly declining evening primrose (Primula vulgaris) by bees, butterflies and moths. Earlier, it was assumed that pollinators use the landscape elements 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 India wild varieties are often allowed to grow between mixed crops which is the prevalent method of agriculture. Natural corridors are 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. 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.

Sharmila Kher
Down To Earth Feature Service

More CO2 could stir the oceans

Here is another consequence of rising carbon dioxide emissions: the oceans are getting louder. It has long been known that chemical compounds in seawater, including boric acid, absorb sound, as energy from sound waves stimulates certain reactions. As the oceans grow more acidic, a result of increasing absorption of atmospheric CO2, the seawater chemistry changes, resulting in fewer reactions and less acoustic energy used. That means sounds will travel farther and be louder at a given distance from a sound source.

Tatiana Ilyina and Richard E Zeebe of the University of Hawaii, and Peter G Brewer of the Monterey Bay Aquarium Research Institute looked at the future impact of this phenomenon. Using a global ocean model and projections of CO2 emissions, they predicted regional changes in acidity, and thus sound absorption.

Writing in Nature Geoscience, they report that in high latitudes and deepwater formations (where acidification is expected to be worse), sound absorption could fall 60 percent by 2100.

So the oceans will not be as quiet, what’s wrong with that?  The noise may be bad news for marine mammals, which use sounds in the same range for communication and echolocation while foraging.

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