Insect pollinator numbers are affected by many different environmental and socio-economic factors but attributing long term change in pollinator numbers to one or more of these is difficult. Scientists are beginning to understand how these different factors interact with each other, and which are more important for particular insect groups, but there is no single, simple explanation for pollinator decline.
Global warming is serving to “crush bumblebees in a kind of climate vice”, according to the leader of a team that has revealed a dramatic shrinkage in the range of these crucial pollinators.
Figuring out exactly how something so huge as climate change effects bee populations is tricky, but possible. To get the details on why and how this is happening, researchers go out into the field and mess with individual flower patches.
indeed Many environmental changes can reduce pollinators’access to essential resources such as food, nest sites and overwintering sites, or directly affect pollinator health:
1-Loss of wild habitats, changes in crops being grown,exposure to chemical pesticides, climate change,disease, changes to the plant community, and economic or cultural changes affecting keeping of honeybees can all contribute
2- Loss of flower-rich habitats such as hay meadows, rough grassland, woodland and hedgerows is often considered to be the main driver of changes in wild pollinator communities during the late 20th century. This particularly affects species with specialized ecological requirements.
3-Intensive farming, with simplified crop rotations in large fields, high herbicide and fertilizer use and high livestock densities can have a negative impact on pollinators, due to the loss of flowers and nesting areas. Flowering crops(eg orchards, oilseed rape) do not compensate because
they only provide transient nectar and pollen sources.
4- Insecticides have been shown to affect the health and behaviour of honeybee and bumblebee colonies in laboratory and small-scale outdoor experiments, even at levels that don’t kill the bees. However, the actual levels of insecticide that pollinators encounter in the
real environment are difficult to assess accurately.
5- Wild insects and plants are already changing their distributions on a large scale in response to climate change. This may disrupt pollination if important pollinators become desynchronized with the plants they pollinate.
It must be noted that Pollinators are the lifeblood of ecosystems everywhere. They help plants reproduce, increase biodiversity, facilitate the dispersal of species into new regions, maintain genetic diversity within plant populations, increase fruit yields, and thereby support flora and fauna at every level of the food chain. Bees are amongst the most important pollinators of all—particularly when it comes to supporting humans.
Climate change is a big threat to all insect world world,we must join hand together to educate the society