Extinction at the end-Cretaceous and the origin of modern Neotropical rainforests

Abstract

The end-Cretaceous event was catastrophic for terrestrial communities worldwide, yet its long-lasting effect on tropical forests remains largely unknown. We quantified plant extinction and ecological change in tropical forests resulting from the end-Cretaceous event using fossil pollen (>50,000 occurrences) and leaves (>6000 specimens) from localities in Colombia. Late Cretaceous (Maastrichtian) rainforests were characterized by an open canopy and diverse plant–insect interactions. Plant diversity declined by 45% at the Cretaceous–Paleogene boundary and did not recover for ~6 million years. Paleocene forests resembled modern Neotropical rainforests, with a closed canopy and multistratal structure dominated by angiosperms. The end-Cretaceous event triggered a long interval of low plant diversity in the Neotropics and the evolutionary assembly of today’s most diverse terrestrial ecosystem.

Biodiversity across space and time in the fossil record

“…Skeletonizing marine animals are the traditional targets of fossil record diversity studies, but important data are also available for plants 12,26 (especially pollen and spores 99,100 ), land animals 69,87,90,101 and plankton 23,102 among others. The availability of these different study systems provides insights into biodiversity patterns across a wide range of environments for various, fundamentally different types of organisms.…”

Ecology and Evolution of Gall-Inducing Arthropods: The Pattern From the Terrestrial Fossil Record

“…A 58-million-year-old flora from the Cerrejón Fm from La Guarjira Province of northernmost Colombia represents a very early record of a Neotropical rainforest (Wing et al, 2009; also see Carvalho et al, 2021;Giraldo et al, 2021). However, although the rate of herbivory of well-preserved leaves was high, at 50%, the richness of DTs among all FFGs in both bulk samples and on individual leaf specimens show rather low levels.…”

“…The gall DTs documented in the recent update (late 2020) to Version 3 of the Guide to Insect (and Other) Damage Types on Compressed Plant Fossils heretofore referred to as the Insect Damage Guide-includes earlier documentation for fossil gall DT occurrences (Ash, 1972(Ash, , 1997Van Amerom, 1973;Hickey and Doyle, 1977;Lewis, 1985;Grauvogel-Stamm and Kelber, 1996;Wilf et al, 2005) and was followed by addenda that document DT occurrences after the 2007 publication date (Currano et al, 2008(Currano et al, , 2010Krassilov, 2008;Wappler et al, 2009Wappler et al, , 2012Stull et al, 2013;Schachat et al, 2014Ding et al, 2015;Wong et al, 2015;Herrera et al, 2017;Donovan et al, 2018Donovan et al, , 2020Labandeira et al, 2018;Xu et al, 2018;Carvalho et al, 2021;also Xiao and Labandeira, 2020: personal observation). The Insect Damage Guide lists 407 DTs, of which 93 (22.9%) are galls.…”

The evolution of open habitats in North America revealed by deep learning models

“…The different types of vegetation and their spatial distribution form the biotic landscape on which other species, including all terrestrial animals, interact and evolve. From reconstructions of past vegetation (paleovegetation) at different sites, we know that vegetation evolves and changes dynamically through time as it responds to environmental alternations, such as changes in climate 1,2 , interaction with faunal communities 3 , and large biological events such as mass extinctions 4 .…”

“…Several major vegetation changes are documented in the fossil record, including the shift from ecosystems dominated by free-sporing plants to seed plants 5 and the radiation and ecological expansion of angiosperms 4,6,7 , which today dominate most terrestrial biomes. The most important vegetation change in the Cenozoic is arguably the origination and expansion of open, grass-dominated habitats 8 at the expense of closed forest ecosystems 9 .…”