13.03.2020 |

Urgent action is needed to stop insect apocalypse, scientists warn

Wild bees are in decline (Photo: CC0)

Insect declines lead to the loss of essential, irreplaceable services to humanity, the consequences of which are unpredictable, scientists have warned. They are calling for urgent action to halt population declines and further extinctions. In two papers, published in the February issue of the journal “Biological Conservation”, 30 experts from around the world review what is known about the drivers of insect decline and the consequences, and suggest practical solutions to mitigate the insect apocalypse. First of all, the researchers point to a lack of knowledge: “The current extinction crisis is deeply worrisome. Yet, what we know is only the tip of the iceberg,” they write, arguing that the number of threatened insect species is woefully underestimated because so many species are undescribed. Current estimates suggest that insects may number 5.5 million species. “It is surprising how little we know about biodiversity at a global level, when only about 10 to 20 % of insect and other invertebrate species have been described and named,” said lead author Pedro Cardoso from the Finnish Museum of Natural History Luomus and University of Helsinki, Finland. “However, it is likely that insect extinctions since the industrial era are around 5 to 10%, i.e. 250,000 to 500,000 species,” the authors write. “In total at least one million species are facing extinction in the coming decades, half of them being insects.”

The main drivers of insect extinctions outlined in the paper are habitat loss, pollution, invasive species, climate change, and overexploitation. “Habitat loss, degradation, and fragmentation are probably the most relevant threats to biodiversity,” the authors write. “Processes associated with deforestation, agricultural expansion, and urbanization are the proximate drivers of loss of natural or semi-natural habitats and their insect assemblages.” According to recent modelling, agro-economic pressure for land will reduce the currently very restricted natural intact vegetation by a further 50% by 2050 in one third of the world’s biodiversity hotspots. Pollution, including harmful agricultural practice, is another key cause of species extinction. “Pesticides are key drivers of insect declines due to their intensive use, as well as inappropriate risk assessment regulations,” the authors find. “Pesticides impact insect populations via direct toxicity and sub-lethal effects (mainly insecticides), and indirectly through habitat alteration (mainly herbicides).”

The consequences of insect declines and extinction are dire since “the fate of humans and insects intertwine”, the scientists warn. We lose biomass, diversity, unique histories, functions, and interaction networks. “With species loss, we lose not only another piece of the complex puzzle that is our living world, but also biomass, essential for example to feed other animals in the living chain, unique genes and substances that might one day contribute to cure diseases, and ecosystem functions on which humanity depends,” highlights Cardoso. Ecosystem functions include pollination, as most crops depend on insects to survive. Insect pollination may have an economic value of $235–577 billion per year worldwide. “Insect declines can negatively affect the maintenance of food supply and put at risk human well-being,” the authors warn. Other functions are nutrient and energy cycling, pest suppression, seed dispersal, and decomposition of organic matter.

The scientists appeal for urgent action to close key knowledge gaps and curb insect extinctions. An investment in research programs that generate local, regional and global strategies that counter this trend is essential, they say. “Many solutions are now available to support insect populations at sustainable levels, especially through preserving and recovering natural habitats, eliminating deleterious agricultural practices including harmful pesticides, implementing measures for avoiding or eliminating the negative impacts of invasive species, taking aggressive steps to reduce greenhouse gas emissions, and curbing the deleterious effects of overexploitation of many taxa.” In order to maintain insect habitats, “key is to have more expansive sustainable agriculture and forestry, improved regulation and prevention of environmental risks, and greater recognition of protected areas alongside agro-ecology in novel landscapes,” the authors write. In addition, engaging civil society and policy makers is essential. “While small groups of people can impact insect conservation locally, collective consciousness and a globally coordinated effort for species inventorying, monitoring and conservation is required for large-scale recovery” says Michael Samways, Distinguished Professor at Stellenbosch University, South Africa. “Solutions are now available – we must act upon them,” the scientists conclude. (ab)

Back to news list


Donors of globalagriculture Bread for all biovision Bread for the World Misereor Heidehof Stiftung Hilfswerk der Evangelischen Kirchen Schweiz Rapunzel
English versionDeutsche VersionDeutsche Version