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.
Many insects, mosses and lichens in the UK are bucking the trend of biodiversity loss, according to a comprehensive analysis of over 5,000 species led by UCL and the UK Centre for Ecology & Hydrology (UKCEH). The researchers say their findings on UK biodiversity between 1970 and 2015, published in Nature Ecology & Evolution, may provide evidence that efforts to improve air and water quality could be paying off.
Since the mid-1990s, populations of the common Japanese dragonfly Sympetrum frequens in rice fields have declined severely. Application of systemic insecticides—especially fipronil—to nursery boxes of rice seedlings is suspected to be the main cause of the decline. However, until now there have been insufficient population data to test the causality. We conducted a dragonfly survey from 2009 to 2016 in four prefectures of Japan and compiled the data to enable the comparison of population growth rates along five main census routes over the years.
Short-term peaks of contaminant concentrations and flows go undetected at many minesites. Recent biological studies have shown that short peaks can contribute significantly to toxicity due to aspects like damage per unit of time, accumulating damage through time, damage at any concentration, temporally aligned or offset synergistic and antagonistic interactions, and slowly reversible or non-reversible uptake and binding of some metals and other elements.
Since 2013, a European Union (EU) moratorium has restricted the application of three neonicotinoids to crops that attract bees because of the harmful effects they are deemed to have on these insects. Yet researchers from the CNRS, INRA, and the Institut de l'Abeille (ITSAP) have just demonstrated that residues of these insecticides -- and especially of imidacloprid -- can still be detected in rape nectar from 48% of the plots of studied fields, their concentrations varying greatly over the years.