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The Potential of Roadside Vegetation for Pollinator Conservation by sneha verma

Populations of pollinating species are diminishing worldwide, reducing the yields of pollinator-dependent crops as well as the prevalence of flowering plants in the ecosystem. According to the IPBES Assessment Report on Pollinators, Pollination and Food Production, 87.5 per cent of the world’s flowers are dependent partly or entirely on insects and other animal pollinations for their reproduction.

These population declines are caused largely by changes in land use. Urbanization and intensive agriculture, among others, reduce the area of habitat or deteriorate the quality of habitats that support pollinator populations. Agricultural pesticides and insecticides, tillage, mono-cropping pattern, climate change and disease also diminish pollinator populations.

Pollinators play a vital role in our food production system. Pollinator-dependent crops account for about 35 per cent of global food production annually, worth between US$ 235–577. Such crops include fruits, vegetables, nuts and oils, which are major sources of vitamins and minerals required for a balanced diet.

Despite providing valuable services like reproduction of plant species in ecosystems and supporting many life forms on earth, certain keystone species are facing an imminent threat of extinction. Among eight native honeybee species of Asia, the Apis cerana swarm has been reported to decline in the whole region. Similarly, Apis andreniformis has become a rare sight in Thailand, Vietnam and Cambodia.

Worldwide, millions of hectares of land have been allocated for road construction and development. Managing such lands with carefully chosen vegetation can help pollinators thrive.

Developers of road projects can offset the loss of pollinator habitats and the concomitant reduction in pollination services by planting selected vegetation on roadsides. In the United States, an estimated 10 million acres of roadways are being set aside for Integrated Roadside Vegetation Management as potential habitats for pollinators.

Well-chosen roadside trees, shrubs, grasses and forbs provide a habitat in which pollinators can nest, breed, rear their young and find nectar. For instance, the monarch butterfly seeks out milkweed, which is present on roadside lands, for laying eggs and nectar. Roadside vegetation can also help connect the fragmented habitats of insects, birds, bats and other species.

Research has shown that to provide habitat for a large variety of pollinator species, a road project should feature different types of trees, shrubs and grasses that vary in floral morphology, colour and height. Mixtures of native as well as non-invasive exotic plants that bloom at different times of the year are particularly conducive to pollinator diversity. Some common plants that attract pollinators are sunflower, lavender, rosemary, mint and native fruit trees.

The United Kingdom, Netherlands and Australia are among countries that have long considered how road verges can contribute to the conservation of bees, butterflies and other pollinating species. The North American Pollinator Protection Campaign was created with a mission to encourage the health of resident and migratory pollinating animals; every year, it honours transportation agencies that support pollinator conservation by creating pollinator-friendly roadways.

How can you help create such pathways along roadsides?

  • If you own land adjacent to a roadside, you can support the road verge habitat by planting a wide variety of complementing flora.
  • Consider eliminating toxic pesticides and instead opt for pollinator-friendly pest management services.
  • Create a shallow water drip and a damp salt lick as useful water sources for butterflies and bees.
  • Dead trees are not necessarily waste. Consider leaving them or even making holes in them for pollinators to have a safe nesting site.

Credits:

(1) Photo by Jungeyon on Pixabay (2) Photo by Crisco 1492, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons (3) Photo by PhamHieu on Pixabay