Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxonomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape.The paper ends with the following:
The widespread insect biomass decline is alarming, ever more so as all traps were placed in protected areas that are meant to preserve ecosystem functions and biodiversity. While the gradual decline of rare insect species has been known for quite some time (e.g. specialized butterflies [9, 66]), our results illustrate an ongoing and rapid decline in total amount of airborne insects active in space and time. Agricultural intensification, including the disappearance of field margins and new crop protection methods has been associated with an overall decline of biodiversity in plants, insects, birds and other species in the current landscape [20, 27, 67]. The major and hitherto unrecognized loss of insect biomass that we report here for protected areas, adds a new dimension to this discussion, because it must have cascading effects across trophic levels and numerous other ecosystem effects. There is an urgent need to uncover the causes of this decline, its geographical extent, and to understand the ramifications of the decline for ecosystems and ecosystem services.
There's been a tonne of media coverage. The Guardian's George Monbiot argues that this erasure of non-human life from the land by farming (industrial fishing being the other huge issue which, all over the blue planet, is now causing systemic ecological collapse) is even worse than climate breakdown!!!! Monbiot writes, 'the most likely cause of this Insectageddon is that the land surrounding those reserves has become hostile to them: the volume of pesticides and the destruction of habitat have turned farmland into a wildlife desert."
We all need to do our part.
Again, urban environments can support flying insects and other pollinators. Everybody can do something about this critical conservation issue and plant for nature. Do it at your residence, do it at your place of worship, or in your parks, or businesses, or places of work, but plant something for the bees and other critters, and for us, poor humans that we are.
Please check out these links to learn how urban centres can support pollinators and go plant a native species!
The city as a refuge for insect pollinators
Toronto's Draft Pollinator Protection Strategy (Hamilton, we need one).
Bees in the city: urban environments could help support pollinators
Can cities save bees? How can urban habitats be made to serve pollinator conservation? How can that story be better told?