In nature, timing is everything

OP-ED Migration of different species of animals and birds is also getting affected by rising temperatures, since migration takes place to help them optimize resources in multiple locations

Sadhna Shanker

In nature and as in life, timing is everything. With this month marking the World Environment Day, a look at the problems that occur in nature due to changing climate patterns affecting timing is important. The United Nations Environment Program (UNEP) Frontiers 2022 Report deals in its final and third chapter with ‘Phenology’.

When we look around us it seems natural that butterflies come when the flowers are in bloom, bird chicks hatch when there is a lot of food around, and lizards in our houses disappear in winter. Phenology studies the timing of recurring biological life cycle events, and how changes in the environment impacts interacting species.

Scientific enquiry into the impact of climate change on phenology of plants and animals is somewhat simpler in parts of the world where the seasons are clearly demarcated. In tropical countries, this study is slightly difficult, because temperatures, rainfall and daylight don’t change much. However, these changes are occurring everywhere, and when timing mismatches occur in nature, the outcome affects the entire ecosystem.

The commonly found hole nesting songbird in Europe and Asia, ‘the great tit’ has many offspring in one hatching, and they need a large number of caterpillars to feed upon. It has been observed that in many areas, because of early onset of summer the birds hatch earlier, but the caterpillar is not breeding at that time, leading to a mismatch and lack of food for the young birds, which in turn affects the entire eco system.

Migration of different species of animals and birds is also getting affected by rising temperatures, since migration takes place to help them optimize resources in multiple locations. The well-known Monarch butterfly flies from Canada to Mexico in winter, a distance of nearly 4000 km. It has been seen that the butterflies have delayed their migration by nearly 6 days per decade due to warmer temperatures. Due to late migration, many butterflies are unable to reach the warmer destination, probably due to timing mismatch in food supply on the way.

Ask any farmer about crops, they will often describe that long hot summers, or erratic rainfall is impacting the cropping patterns. Plants are impacted in all their processes in response to rising temperatures and uneven rainfall. Be it leafing, flowering or fruit production. Life cycles of staple crops across the globe are changing due to climate unpredictability. These include barley, maize, rice, soybean, wheat, cotton, grapevines, and fruit trees. These changes lead to changes in crop varieties and other farming decisions. Such decisions have an impact on soil, and on insects and pests that interact with crops. These have long term consequences on food availability.

We have all heard of many varieties of fish and other marine life becoming scarce in many parts of the world. Rising water temperatures show timing changes much more quickly in marine life than on land. Since the spawning and growth of many marine species is affected by temperature, lower survival of the young affect’s adult marine population.

In India, studies have shown timing changes in the life cycle of major forest trees of Kumaon Himalayas, and studies are ongoing on mismatches between plants and insects, which could impact issues of food security. 

We often observe and discuss the abnormally hot summers, the sudden heavier thundershowers, and the shorter colder winters. We need to understand that climate change, apart from making day to day living difficult, is also affecting the timing of life cycles in living things around us. The affected plants and animals try and adjust to the changed climate, but often the adjustments are not in synch with each other. These mismatches have long term impacts, which potentially threaten all of us on the globe.

Sadhna Shanker is a writer based in New Delhi, India

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