The decline of butterflies in Europe: Problems, significance, and possible solutions

Abstract

We review changes in the status of butterflies in Europe, focusing on long-running population data available for the United Kingdom, the Netherlands, and Belgium, based on standardized monitoring transects. In the United Kingdom, 8% of resident species have become extinct, and since 1976 overall numbers declined by around 50%. In the Netherlands, 20% of species have become extinct, and since 1990 overall numbers in the country declined by 50%. Distribution trends showed that butterfly distributions began decreasing long ago, and between 1890 and 1940, distributions declined by 80%. In Flanders (Belgium), 20 butterflies have become extinct (29%), and between 1992 and 2007 overall numbers declined by around 30%. A European Grassland Butterfly Indicator from 16 European countries shows there has been a 39% decline of grassland butterflies since 1990. The 2010 Red List of European butterflies listed 38 of the 482 European species (8%) as threatened and 44 species (10%) as near threatened (note that 47 species were not assessed). A country level analysis indicates that the average Red List rating is highest in central and mid-Western Europe and lowest in the far north of Europe and around the Mediterranean. The causes of the decline of butterflies are thought to be similar in most countries, mainly habitat loss and degradation and chemical pollution. Climate change is allowing many species to spread northward while bringing new threats to susceptible species. We describe examples of possible conservation solutions and a summary of policy changes needed to conserve butterflies and other insects.

Agricultural intensification and climate change are rapidly decreasing insect biodiversity

“…Taxa that are especially diverse in these ecosystems include butterflies and noctuid moths (Lepidoptera); ants, bees, and wasps (Hymenoptera); scarab and ground beetles (Coleoptera); crickets, grasshoppers, and katydids (Orthoptera); leaf and plant hoppers, seed bugs, and their kin (Heteroptera). Of these, only butterflies have been well studied; across Europe, grassland butterflies rank among the most imperiled insects (35,36,47,48).…”

Climate drivers of adult insect activity are conditioned by life history traits

“…Longer insect activity periods may buffer against phenological mismatch of insects interacting with other trophic levels, as long as insect abundance is sufficiently high. However, mounting evidence suggests widespread terrestrial insect declines (van Klink et al, 2020;Wagner et al, 2021;Warren et al, 2021), which raises the threat of reduced ecological services regardless of how much synchrony occurs between interacting species.…”

Arthropods are not declining but are responsive to disturbance in the Luquillo Experimental Forest, Puerto Rico

“…insect decline | hurricane | disturbance | global warming | species turnover S everal long-term studies in Europe and North America have documented declines in important insect groups, notably butterflies, moths, bees, flying beetles, and wood-borers (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). These studies have attributed declines to a variety of causes, primarily habitat loss, but also increased insecticide use, light pollution, and climate change, particularly in developed countries in the northern hemisphere.…”