A unique analysis spanning nine decades reveals that insect populations in Switzerland have undergone profound transformations, particularly between the 1930s and 1980s. Saproxylic beetles, which depend on dead wood for survival, and butterflies, essential for pollination, saw a significant decline in species richness during this period. The former experienced a marked decline as early as the 1930s, followed by stabilization and a slight recovery starting in the 2000s. In contrast, butterflies continued to decline until the 1980s, never regaining their initial levels.<\/p>\n
This decline coincides with a period of major agricultural intensification, particularly between the 1950s and 1980s. The widespread introduction of agricultural machinery transformed landscapes, reducing natural habitats such as semi-natural grasslands and ancient forests. These changes particularly affected specialized species, which were unable to adapt to simplified and impoverished environments. Saproxylic beetles, for example, suffered from the disappearance of dead wood, a vital resource for their life cycle. Butterflies, on the other hand, were affected by the reduction of specific host plants, which are essential for their survival.<\/p>\n
From the 1980s onward, a reverse trend emerged for some species. Climate warming favored insects adapted to higher temperatures, while cold-adapted species continued to decline. Saproxylic beetles also benefited from the increased availability of dead wood, thanks to storms and more biodiversity-friendly forest management. These events created more favorable conditions, such as better light exposure and increased food resources.<\/p>\n
Differences between Swiss regions are also pronounced. In the plateau and Northern Alps, where agriculture is most intensive, butterflies suffered the greatest losses, with declines reaching nearly 30%. In contrast, in the Central Alps and the Jura, declines were less pronounced or even stabilized for some species. These variations are explained by different levels of agricultural intensification and forest management.<\/p>\n
Generalist species, capable of thriving in various habitats, have fared better than specialists, which depend on very specific environmental conditions. Among the latter, large saproxylic beetles and small butterflies were the most affected. The former require large-diameter trunks, which have become rare due to intensive forest management. The latter, being less mobile, struggle to adapt to fragmented landscapes and rapid changes.<\/p>\n
Species adapted to warm temperatures, however, experienced a rebound after 1980, benefiting from accelerated climate warming. In contrast, cold-adapted species continued to decline, particularly in mountain regions where their habitats are shrinking. This phenomenon illustrates a restructuring of insect communities, where winners and losers emerge based on their ability to adapt to new conditions.<\/p>\n
This study shows that conservation decisions must account for historical changes and climate effects. Reducing the impact of agricultural and forestry practices remains essential to preserving insect diversity. Recent measures to support biodiversity, such as more natural forest management and agri-environmental programs, have already helped stabilize some populations. However, specialized species continue to suffer, highlighting the importance of restoring their habitats and improving landscape connectivity.<\/p>\n
DOI:<\/strong> https:\/\/doi.org\/10.1038\/s41559-026-03074-6<\/a><\/p>\n Title:<\/strong> Ninety-year trends reveal sharpest insect declines in the mid-twentieth century<\/p>\n Journal:<\/strong> Nature Ecology & Evolution<\/p>\n Publisher:<\/strong> Springer Science and Business Media LLC<\/p>\n Authors:<\/strong> Felix Neff; Kurt Bollmann; Yannick Chittaro; Martin M. Gossner; Felix Herzog; Fr\u00e4nzi Korner-Nievergelt; Glenn Litsios; Carlos Mart\u00ednez-N\u00fa\u00f1ez; Marco Moretti; Emmanuel Rey; Andreas Sanchez; Eva Knop<\/p>\n","protected":false},"excerpt":{"rendered":" Did Insects Experience Their Most Significant Decline in the Mid-20th Century? A unique analysis spanning nine decades reveals that insect populations in Switzerland have undergone profound transformations, particularly between the 1930s and 1980s. Saproxylic beetles, which depend on dead wood for survival, and butterflies, essential for pollination, saw a significant decline in species richness during… Continue reading Did Insects Experience Their Most Significant Decline in the Mid-20th Century?<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,2],"tags":[],"class_list":["post-45","post","type-post","status-publish","format-standard","hentry","category-culture","category-environment","entry"],"_links":{"self":[{"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/posts\/45","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/comments?post=45"}],"version-history":[{"count":1,"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/posts\/45\/revisions"}],"predecessor-version":[{"id":46,"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/posts\/45\/revisions\/46"}],"wp:attachment":[{"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/media?parent=45"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/categories?post=45"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/biodiversityreview.com\/en\/wp-json\/wp\/v2\/tags?post=45"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}