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Mass extinction events and the plant fossil record
Abstract and Figures
Five mass extinction events have punctuated the geological record of marine invertebrate life. They are characterized by faunal extinction rates and magnitudes that far exceed those observed elsewhere in the geological record. Despite compelling evidence that these extinction events were probably driven by dramatic global environmental change, they were originally thought to have little macroecological or evolutionary consequence for terrestrial plants. New high-resolution regional palaeoecological studies are beginning to challenge this orthodoxy, providing evidence for extensive ecological upheaval, high species-level turnover and recovery intervals lasting millions of years. The challenge ahead is to establish the geographical extent of the ecological upheaval, because reconstructing the vegetation dynamics associated with these events will elucidate the role of floral change in faunal mass extinction and provide a better understanding of how plants have historically responded to global environmental change similar to that anticipated for our future.
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... Data from past mass extinctions indicate that plants did not follow the same patterns as animal groups (Wing 2004;McElwain and Punyasena 2007;Green et al. 2011). During these mass extinction events, plants did not undergo family-level extinctions (McElwain and Punyasena 2007;Thompson and Ramírez-Barahona 2023;Wilf et al. 2023); instead, selective extirpation of species at the local or regional level unseated dominant plant taxa and allowed so-called disaster taxa to flourish until stable plant communities reemerged (McElwain and Punyasena 2007;Vajda and Bercovici 2014;Wilf et al. 2023). ...
... Data from past mass extinctions indicate that plants did not follow the same patterns as animal groups (Wing 2004;McElwain and Punyasena 2007;Green et al. 2011). During these mass extinction events, plants did not undergo family-level extinctions (McElwain and Punyasena 2007;Thompson and Ramírez-Barahona 2023;Wilf et al. 2023); instead, selective extirpation of species at the local or regional level unseated dominant plant taxa and allowed so-called disaster taxa to flourish until stable plant communities reemerged (McElwain and Punyasena 2007;Vajda and Bercovici 2014;Wilf et al. 2023). By comparison, terrestrial faunas experienced up to 62% extinction of global families during past mass extinctions (Benton 1995). ...
... Data from past mass extinctions indicate that plants did not follow the same patterns as animal groups (Wing 2004;McElwain and Punyasena 2007;Green et al. 2011). During these mass extinction events, plants did not undergo family-level extinctions (McElwain and Punyasena 2007;Thompson and Ramírez-Barahona 2023;Wilf et al. 2023); instead, selective extirpation of species at the local or regional level unseated dominant plant taxa and allowed so-called disaster taxa to flourish until stable plant communities reemerged (McElwain and Punyasena 2007;Vajda and Bercovici 2014;Wilf et al. 2023). By comparison, terrestrial faunas experienced up to 62% extinction of global families during past mass extinctions (Benton 1995). ...
The Cretaceous/Paleogene (K/Pg) mass extinction was a pivotal event in Earth history, the latest among five mass extinctions that devastated marine and terrestrial life. Whereas much research has focused on the global demise of dominant vertebrate groups, less is known about changes among plant communities during the K/Pg mass extinction. This study investigates a suite of 11 floral assemblages leading up to and across the K/Pg boundary in northeastern Montana constrained within a well-resolved chronostratigraphic framework. We evaluate the impact of the mass extinction on local plant communities as well as the timing of post-K/Pg recovery. Our results indicate that taxonomic composition changed significantly from the Late Cretaceous to Paleocene; we estimate that 63% of latest-Cretaceous plant taxa disappeared across the K/Pg boundary, on par with other records from North America. Overall, taxonomic richness dropped by ~23–33% from the Late Cretaceous to the Paleocene, a moderate decline compared with other plant records from this time. However, richness returned to Late Cretaceous levels within 900 kyr after the K/Pg boundary, significantly faster than observed elsewhere. We find no evidence that these results are due to preservational bias (i.e., differences in depositional environment) and instead interpret a dramatic effect of the K/Pg mass extinction on plant diversity and ecology. Overall, plant communities experienced major restructuring, that is, changes in relative abundance and unseating of dominant groups during the K/Pg mass extinction, even though no major (e.g., family-level) plant groups went extinct and communities in Montana quickly recovered in terms of taxonomic diversity. These results have direct bearing on our understanding of vegetation change during diversity crises, the differing responses of plant groups (e.g., angiosperms vs. gymnosperms), and spatial variation in extinction and recovery timing.
... There were several times in Earth's history when continental ecosystems were disturbed or even destroyed by climate change (e.g., DiMichele et al., 2004;McElwain and Punyasena, 2007). Considering that plants form the foundations of terrestrial trophic webs and are particularly sensitive to climate (Grimm et al., 2013), it is possible to recognize when life on land was impacted by severe climatic changes (Boyce and Lee, 2017) by looking for shifts in fossil plant communities (e.g., Hochuli and Vigran, 2010;Hermann et al., 2011a;Mays et al., 2020Mays et al., , 2021aShu et al., 2023). ...
... Plant fossil records reveal major changes in floral community compositions due to impactful global climatic events during the late Permian to Middle Triassic (Fig. 9), without the same degree of species extinction seen in coeval animal fossil records (McElwain and Punyasena, 2007;Cascales-Miñana and Cleal, 2014;Nowak et al., 2019;Xiong et al., 2021). Although we cannot assume the predicted behavior of plants under climatic changes, here we consider that the survival of certain groups was principally the result of physiological traits that promoted resilience to stress and/or latitudinal and altitudinal migration. ...
The end-Permian event (EPE, ca. 252.3−251.9 Ma) led to the generalized collapse of gymnosperm-supported ecosystems. They eventually recovered despite Early Triassic suppression and became globally dominant for most of the Mesozoic. Understanding the sequence and timing of gymnosperm reestablishment at different latitudes is therefore key to explaining how they regained their foothold. Given the limited data on polar plant communities, here we present the first high-resolution, age-controlled floristic trends from the high southern latitudes (Sydney Basin, Australia; ∼70°S) from the latest Permian to the Middle Triassic. Sedimentological and biostratigraphic data and stable carbon isotope ratios of organic matter were used to establish lithostratigraphic correlations, paleoenvironmental insights, and links to the global chronostratigraphy.
Non-metric multidimensional scaling of spore-pollen groupings confirmed that the late Smithian thermal maximum (LSTM, ca. 250.3−249.6 Ma) and the Smithian-Spathian event (SSE, ca. 249.6−249.2 Ma) were the primary drivers of significant Early Triassic ecosystem changes in the Sydney Basin. Following the EPE, ecosystems supported by peltasperm seed ferns were the first to establish, lasting for ∼200,000 years. Voltzialean conifers were thereafter dominant for ∼1.5 million years until the LSTM. Stress-tolerant cosmopolitan pleuromeian lycophytes then became the predominant flora, lasting ∼800,000 years until SSE-associated cooling allowed umkomasialean seed ferns to expand, which persisted and ultimately characterized Middle-to-Late Triassic high-latitude Gondwanan ecosystems. Global comparisons showed that pleuromeians surged under extreme post-EPE conditions, but their rise was delayed by ∼1.7 million years in the polar south. Our findings support the hypothesis that the post-EPE interval was a staggered process rather than one of monotonic recovery, with gymnosperm and lycophyte floral communities waxing and waning in succession until the early Middle Triassic.
... ref. 45). Plant taxonomy heavily relies on floral characteristics, which are rarely well preserved, traditionally limiting the study of past plant extinctions making direct comparisons of plant extinction at genus of family level especially during mass extinction events, distinct from the Pleistocene/Holocene transition 46 . ...
During the Pleistocene-Holocene transition, the dominant mammoth steppe ecosystem across northern Eurasia vanished, in parallel with megafauna extinctions. However, plant extinction patterns are rarely detected due to lack of identifiable fossil records. Here, we introduce a method for detection of plant taxa loss at regional (extirpation) to potentially global scale (extinction) and their causes, as determined from ancient plant DNA metabarcoding in sediment cores (sedaDNA) from lakes in Siberia and Alaska over the past 28,000 years. Overall, potential plant extinctions track changes in temperature, in vegetation, and in megafauna extinctions at the Pleistocene-Holocene transition. Estimated potential plant extinction rates were 1.7–5.9 extinctions per million species years (E/MSY), above background extinction rates but below modern estimates. Major potential plant extinction events were detected around 17,000 and 9000 years ago which lag maximum vegetation turnover. Our results indicate that herbaceous taxa and taxa contributing less to beta diversity are more vulnerable to extinction. While the robustness of the estimates will increase as DNA reference libraries and ancient sedaDNA data expand, the available data support that plants are more resilient to environmental changes than mammals.
... Polyploidy, the possession of more than two sets of chromosomes in a cell, is common and taxonomically/phylogenetically widespread in angiosperms (Lewis 1980;Masterson 1994;Otto and Whitton 2000;Comai 2005;Madlung 2013;Tank et al. 2015;Rice et al. 2019, including the world's most important crops (Bennett 2004;Sattler et al. 2016). In fact, most angiosperms have polyploidy in their evolutionary history (Adams and Wendel 2005;Soltis and Burleigh 2009), and polyploidization (whole-genome duplication) is thought to have been a force in angiosperm diversification (Petit et al. 1999;McElwain and Punyasena 2007;Fawcett et al. 2009;Soltis et al. , 2014aVan de Peer et al. 2009, 2017Van de Peer 2010, 2017;Jiao et al. 2011; Vanneste et al. 2014;Huang et al. 2016;Zhang et al. 2021). ...
Main conclusion
Polyploidization (diploidy → polyploidy) was more likely to be positively associated with seed mass than with seed germination.
Abstract
Polyploidy is common in flowering plants, and polyploidization can be associated with the various stages of a plant’s life cycle. Our primary aim was to determine the association (positive, none or negative) of polyploidy with seed mass/germination via a literature review. We found that the number of cases of positive, none and negative correlates of polyploidization was 28, 36 and 21, respectively, for seed germination and 25, 5 and 3, respectively, for seed mass. In many plant species, ploidy level differs within and between populations, and it may be positively or negatively associated with germination (57.6% of 85 cases in our review). Ideally, then, to accurately assess intra- and interpopulation variation in seed germination, such studies should include ploidy level. This is the first in-depth review of the association of polyploidy with seed germination.
Analysis of palynological assemblages from the Val Daone Conglomerate (VDC) Formation (central Southern Alps) provides significant new information on the age of this lithostratigraphic unit and, therefore, of the inception of the Permian tectono-stratigraphic cycle 2 (TSU2) in the Southern Alps. The VDC Formation represents a nearly 100-m thick, medium-grained fluviatile body which can be followed in western Trentino, from the NE part of the Permian Collio Basin to the west, up to the Val Rendena to the east.
Palynomorphs from the VDC Formation are well- preserved in the Val di Scale (Val Rendena) section but poorly preserved in the Ronchi section (Val Daone). Comparisons between the results of the present study with data from the Tregiovo, Val Gardena Sandstone and Bellerophon formations of the Italian Southern Alps reveal a sequence of distinct associations that are stratigraphically and perhaps palaeoenvironmentally controlled. The stratigraphy of the palynomorph assemblage of the VDC is diagnostic of the late Capitanian-Wuchiapingian. Two different palynozones within the Val Daone Conglomerate PalynoZone - VDCPZ are established from the VDC Formation, the lower (VDCPZ1) from the Ronchi section, attributed to late Capitanian-early Wuchiapingian, and the upper (VDCPZ2) from the Val Rendena section, of Wuchiapingian age. These VDCPZs show close similarities with coeval associations recorded from other European areas. This is consistent with the stratigraphic position of the VDC Formation and allow us: 1) to assign the beginning of the Permian 2nd tectono-sedimentary cycle in this sector of the Southern Alps to the late Capitanian-early Wuchiapingian and 2) to suggest that the depositional hiatus caused by the intra-Permian tectonics straddled most of the Guadalupian and it is partly time-equivalent with the Pangaea gap. Moreover, the VDCPZ1 is one of the few low-latitude associations that are time-equivalent or slightly younger than the end-Guadalupian mass extinction, a major climate-driven event that significantly changed terrestrial faunas.
The Triassic–Jurassic transition was an important interval in Earth’s history, which encompassed two great biotic crises: the End-Triassic mass extinction and the early Toarcian Oceanic Anoxic Event. The response of the terrestrial vegetation to these crises has been the subject of debate. In Argentina, a floristic turnover occurring in the Triassic-Jurassic boundary has been suggested, which led to the disappearance of corystoperms and peltasperms, and to a greater diversity of ferns, bennettitaleans, and conifers. Recent findings have thrown into question the previous evolutionary models. To understand the terrestrial plant turnovers during the Triassic-Jurassic transition in Argentina, we calculated diversity indexes, survivorship proportions, and origination and extinction rates, based on the megafossil record. The results indicated that, despite only one lineage disappeared in the Late Triassic (Pleuromeiaceae), there was an important but gradual vegetation change in the Triassic26 Jurassic transition. Late Triassic diagnostic lineages extended into the Jurassic but most of them with few records and became extinct in the Early Jurassic. Floristic turnovers during the
Jurassic, can be correlated with paleoclimatic changes. The Osmundaceae, Dipteridaceae,and Bennettitales diversified in the Sinemurian. A taxa richness increase in the Toarcian is recognized, marked by a conifer diversification. In the Bathonian-Kimmeridgian interval, the conifers and bennettitaleans acquired greater importance. The dataset can be improved in the future by intensifying fossil sampling in order to obtain more robust and precise results.
Premise
The ecological conditions that constrain plants to an environmental niche are assumed to be constant through time. While the fossil record has been used previously to test for niche conservatism of woody flowering plants, additional studies are needed in other plant groups especially since they can provide insight with paleoclimatic reconstructions, high biodiversity in modern terrestrial ecosystems, and significant contributions to agriculture.
Methods
We tested climatic niche conservatism across time by characterizing the climatic niches of living herbaceous ginger plants (Zingiberaceae) and woody dawn redwood ( Metasequoia ) against paleoniches reconstructed based on fossil distribution data and paleoclimatic models.
Results
Despite few fossil Zingiberaceae occurrences in the latitudinal tropics, unlike living Zingiberaceae, extinct Zingiberaceae likely experienced paratropical conditions in the higher latitudes, especially in the Cretaceous and Paleogene. The living and fossil distributions of Metasequoia largely remain in the upper latitudes of the northern hemisphere. The Zingiberaceae shifted from an initial subtropical climatic paleoniche in the Cretaceous, toward a temperate regime in the late Cenozoic; Metasequoia occupied a more consistent climatic niche over the same time intervals.
Conclusions
Because of the inconsistent climatic niches of Zingiberaceae over geologic time, we are less confident of using them for taxonomic‐based paleoclimatic reconstruction methods like nearest living relative, which assume a consistent climatic niche between extant and extinct relatives; we argue that the consistent climatic niche of Metasequoia is more appropriate for these reconstructions. Niche conservatism cannot be assumed between extant and extinct plants and should be tested further in groups used for paleoclimatic reconstructions.
The extinction of vertebrates around the time of the Permian-Triassic boundary has long been regarded as a gradual event occurring over millions of years. Our new field investigations of fluvial strata in the central and southern Karoo Basin of South Africa have revealed the presence of an event bed coinciding with a mass extinction of terrestrial fauna and flora. The bed is in a sedimentary sequence that is marked by a reddening of flood-plain mud rocks and a change from high- to low-sinuosity river channel systems. Here we show that the pattern of vertebrate taxa disappearing below this boundary and the subsequent appearance of new taxa above the boundary are consistent with a relatively sudden, possibly catastrophic event, perhaps of 50 000 yr duration or less.
Mass extinctions generally are recognized as major features in the history of life. They sweep aside diverse, sometimes even dominant groups of organisms, freeing up resources that can then fuel the diversification and rise to dominance of lineages that survived the mass extinction. This view of the history of life has been developed in large part from the study of shelly marine animals, and to a lesser extent from studies of terrestrial vertebrates (e.g. Valentine, 1985). By compiling data on the stratigraphic ranges of genera and families of marine animals, palaeontologists have been able to recognize the ‘Big Five’ mass extinctions, occurring at the end of the Ordovician, in the Late Devonian and at the end of the Permian, Triassic and Cretaceous periods (e.g. Sepkoski, 1993; Chapters 1 and 5). Each of these episodes is a geologically sudden decrease in taxonomic diversity. Terrestrial vertebrates also show major declines in taxonomic diversity at the end of the Permian and at the end of the Cretaceous (Benton, 1993). In contrast, compilations of the stratigraphic ranges of species of land plants do not show major declines in diversity (Niklas et al., 1980, 1985; Niklas and Tiffney, 1994; Figure 3.1). The absence of major declines in the diversity of land plants as represented in these compilations of stratigraphic ranges has led to the suggestion that plants are more resistant to mass extinctions than animals (Niklas et al., 1980; Knoll, 1984; Traverse, 1988).
Palynology is used to bracket or pinpoint the Cretaceous-Tertiary (K-T) boundary in 17 measured sections near the contact of the Hell Creek Formation and the Ludlow Member of the Fort Union Formation in southwestern North Dakota. Palynostratigraphy is the most reliable method for locating the K-T extinction horizon - which defines the K-T boundary - in nonmarine rocks. The palynological database includes 110 taxa for which relative abundance or presence or absence data were recorded in more than 350 samples based on surveys of more than 700 000 specimens. These data from laterally extensive outcrops in the badlands along the Little Missouri River provide a temporal framework for concurrent studies in the area on megafossil paleobotany, vertebrate paleontology, lithostratigraphy, magnetostratigraphy, and chemostratigraphy. Palynology demonstrates extinction of 30% or more of the Maastrichtian palynoflora, including characteristic Maastrichtian taxa ("K taxa"), at the K-T boundary. Most of the palynomorph taxa discussed probably represent higher-level plant taxa (botanical genera or families). The K-T boundary is shown to be coincident with the Hell Creek-Fort Union formational contact at only two localities; it is as much as 2.7mabove the base of the Fort Union Formation at others. Thus, a distinctive interval of Fort Union strata of Cretaceous age is recognized that is characterized by occurrences of numerous K taxa, usually in low percentage abundance, up to the K-T boundary. This interval documents a regional paleoenvironmental change that is independent of the extinction event and that is important to understanding the K-T transition throughout western North America.