Habitat Disturbance and Warming Climate: Primary Drivers of Decline in Pollinators’ Population

Insects are essential pollinators. Without them, humanity would lose majority of its crops and more people would basically go hungry.

Unfortunately, we are slowly losing a large population of our little pollinators, or "the little things that run the world", according to E.O. Wilson.

The renowned ecologist said that these small invertebrates greatly outnumber vertebrates, as high as 30 million, yet studies suggested they are hardly surviving on our planet.

It is commonly held that insects are so diverse due to their small size and correspondingly divide up the environment into many more little domains.

However, a new study identified major drivers of massive insect population die-offs, in the form of human-created disturbances, ScienceAlert reported.

Humans' disruption of their natural habitat, use of toxic chemicals into their environments, and unprecedented rising temperatures drove the species into widescale declines, according to ScienceAlert.

Moreover, a study published in Nature Ecology and Evolution reported dramatic changes in insect abundance, resulting in grave consequences for global ecosystems and human society.

Agricultural Intensity

University College London ecologist Charlie Outhwaite and colleagues used data on insect abundance and biodiversity in more than 6,000 different locations worldwide, which trended across 20 years and identified two primary drivers of insect die-offs: agricultural intensity and climate warming.

"We found that in high intensity agriculture that has also seen substantial warming, abundance and richness are reduced by 49% and 27% relative to primary vegetation where there has been little warming," Outhwaite said.

On the other hand, areas where natural habitat remains intact shows reduction in nearby insect declines.

In areas with three-quarters of natural habitat still intact, insect die-offs dropped at only 7% on average and the numbers of different species only by 5%.

Meanwhile, there was 63% and 61% total in areas with less than a quarter of remaining natural habitat.

Ecologist Tim Newbold, also from the University College London, explained that "careful management of agricultural areas, such as preserving natural habitats near farmland, may help to ensure that vital insects can still thrive."

Climate Warming

The rising temperature is also proving too much for many species to handle, combined with habitat disturbance, with hardest impacted places in the tropics and the Mediterranean.

For instance, in Brazil, orchid bee population has declined by around 50%.

The year 2011 was the most sensitive to anthropogenic disturbances of all Atlantic Forest orchid bees when habitats no longer held suitable.

Temperate areas on the other hand have experienced an increase in biodiversity with warming, which means not all species are exactly unbenefited.

"Many of these positive trends have been reported in non-tropical regions such as the UK and Europe, where a lot has been done, for example, to improve the water quality of rivers in recent years, following past degradation," Newbold and Outhwaite explained.

Making up massive chunk of all the existing life we know of in the Universe, it is urgent that we determine where we did the insects wrong and mitigate as soon as possible.

This includes "actions to preserve natural habitats, slow the expansion of high-intensity agriculture, and cut emissions to mitigate climate change," said Outhwaite.