Impact of Global Climate Change on Pollinator Diversity and Conservation: Current Issues and Future Challenges

Abstract

Over 75% of the major world crops and 80% of all flowering plant species rely on animal pollinators. Of the hundred or so animal-pollinated crops which make up most of the world's food supply, 15% are pollinated by domestic bees, while at least 80% are pollinated by wild bee species and other wildlife. Most of the 25, 000 to 30, 000 species of bees are effective pollinators, and together with moths, flies, wasps, beetles and butterflies, make up the majority of pollinating species. Vertebrate pollinators include bats, non-flying mammals (several species of monkey, rodents, lemur and tree squirrels etc.) and birds (humming birds, sun birds, honey creepers and some parrot species). Current understanding of pollination process shows that, while an interesting specialized relationship exist between plants and their pollinators, healthy pollination services are best ensured by an abundant diversity of pollinators. Thus, pollinators are essential for diet diversity, biodiversity, and maintenance of natural resources. Pollinators which evolved over million of years, are eroding at a fast rate from the globe. During the past few years, many pollinators especially honey bees have been dying across the globe in unprecedented number and, no one has so far been able to prove beyond a reasonable doubt what the causes may have been. The economic implications of these deaths are immediate because honey bees are integral to the pollination of tens of millions of dollars of cash crops in the world. Despite much of the world's agriculture relying on pollination by honeybees, especially European honeybees, their number across the globe has also declined. Many other pollinators such as digger bees, sweat bees, alkali bees, squash bees, leafcutter bees, carpenter bees, mason bees, and shaggy fuzzy foot bees could also be on decline, but data providing unambiguous documentation of trends are simply not available. Threats to pollinators and the services they provide are perceived to be increasing around the world and are mainly man-made in origin. Climate change could be a major factor in weakening the bees and has affected the pollination of crops in many agricultural areas. An attempt has been made to know the causes behind the decline of pollinators, especially in relation to climate change, their conservation and management and impact of declining pollinator population on horticulture in the changed global scenario.