English

Our mechanistic understanding of the toxicity of chemicals that target biochemical and/or physiological pathways, such as pesticides and medical drugs is that they do so by binding to specific molecules. The nature of the latter molecules (e.g., enzymes, receptors, DNA, proteins, etc.) and the strength of the binding to such chemicals elicit a toxic effect in organisms, which magnitude depends on the doses exposed in a given timeframe.

In what is the first comprehensive assessment of the distribution, abundance and conservation status of bird species in India, a study, titled the State of India’s Birds 2020, has found that the birds in the Western Ghats have seen a steep decline in number in the last 25 years.

Across the expansive Taita Plains in Southern Eastern Kenya, rises a majestic densely forested hilly outcrops straddling the skyline near the historic town of Voi. These hilly outcrops, famously known as the Taita Hills occupy an area of about 250 square kilometers. In addition to being an important biodiversity hotspot and water tower, the densely forested hills form an important ecosystem consisting of a number of forests, home to various animals and rare bird species.

Based on the science available to date, there is evidence to support the claim that bats are being negatively affected by neonicotinoid insecticides in several different ways, indirectly through reduction in insect abundance and directly through impairment.

Snakes have been ”starving” to death after a mass die-off of forest frogs deprived them of their unusual meal, scientists have discovered. More than 500 frog species in central America have declined in numbers, including 90 that have gone extinct since 1998, biologists said. In 2004, a fungal pathogen outbreak caused a mass die-off. In the following years, numbers of snakes and the variety of species plummeted, found researchers from the University of Maryland and Michigan State University.

The abundance of insects has decreased for the last decades in many parts of the world although so far few studies have quantified this reduction because there have only been few baseline studies dating back decades that have allowed comparison of ancient and recent population estimates. Such a paired design is particularly powerful because it reduces or eliminates bias caused by differences in identity and experience of observers, identity of study sites, years, time of season, and time of day, and it ensures identity of sampling procedures.

The “fates of humans and insects are intertwined”, scientists have said, with the huge declines reported in some places only the “tip of the iceberg”. The warning has been issued by 25 experts from around the world, who acknowledge that little is known about most of the estimated 5.5 million insect species. However, enough was understood to warrant immediate action, they said, because waiting for better data would risk irreversible damage.

Hundreds of bird populations in India are collapsing, according to a major new report. Researchers using data collected by more than 15,000 birdwatchers examined trends over a 25-year period, and also over the last five years, and in both cases found numbers had declined overall. Over the last quarter of a century there is data available for 261 species – 52 per cent of which were found to be decreasing in number. And over the past five years, data available for 146 species revealed almost 80 per cent of them were declining.