<i>Hagenia</i> from the early Miocene of Ethiopia: Evidence for possible niche evolution?

Grímsson, Friðgeir; Ulrich, Silvia; Coiro, Mario; Graham, Shirley A.; Jacobs, Bonnie F.; Currano, Ellen D.; Xafis, Alexandros; Zetter, Reinhard

doi:10.1002/ece3.7408

Cited by 6 publications

(3 citation statements)

References 104 publications

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“…A Fossilized Birth–Death prior with sampled ancestor was used, with the tree process conditioned on the origin age, which was set as a uniform distribution between 68.8 and 50.52 Ma based on the age of the MRCA (Most Recent Common Ancestor) node of Vauquelinia and Gillenia Moench in Grímsson et al . (2021).…”

Section: Methodsmentioning

confidence: 99%

Cenozoic migration of a desert plant lineage across the North Atlantic

et al. 2023

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Previous paleobotanical work concluded that Paleogene elements of the sclerophyllous subhumid vegetation of western Eurasia and western North America were endemic to these disjunct regions, suggesting that the southern areas of the Holarctic flora were isolated at that time. Consequently, molecular studies invoked either parallel adaptation to dry climates from related ancestors, or long-distance dispersal in explaining disjunctions between the two regions, dismissing the contemporaneous migration of dry-adapted lineages via land bridges as unlikely.We report Vauquelinia (Rosaceae), currently endemic to western North America, in Cenozoic strata of western Eurasia. Revision of North American fossils previously assigned to Vauquelinia confirmed a single fossil-species of Vauquelinia and one of its close relative Kageneckia.We established taxonomic relationships of fossil-taxa using diagnostic character combinations shared with modern species and constructed a time-calibrated phylogeny.The fossil record suggests that Vauquelinia, currently endemic to arid and subdesert environments, originated under seasonally arid climates in the Eocene of western North America and subsequently crossed the Paleogene North Atlantic land bridge (NALB) to Europe. This pattern is replicated by other sclerophyllous, dry-adapted and warmth-loving plants, suggesting that several of these taxa potentially crossed the North Atlantic via the NALB during Eocene times.

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Section: Methodsmentioning

confidence: 99%

Cenozoic migration of a desert plant lineage across the North Atlantic

et al. 2023

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“…Hagenia forests benefit from disturbances that cause open canopies with abundant light to establish and maintain and Hagenia seeds, which are easily wind‐blown in large numbers to open areas (Fetene and Feleke, 2001; Lange et al , 1997; Young et al , 2017; Grímsson et al , 2021). Mature Hagenia trees are fire‐adapted with relatively flakey, resistant bark (Fetene and Feleke, 2001) and bole architecture that reduces fuel laddering from the ground surface to canopy.…”

Section: Discussionmentioning

confidence: 99%

Late Pleistocene montane forest fire return interval estimates from Mount Kenya

Mustaphi

Rucina

Marchant

2022

J Quaternary Science

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Past forest fire events and fire frequencies are reconstructed with sediment-charcoal records at lake catchment spatial scales. Few quantitative palaeofire analyses exist in tropical montane forests, where fire return intervals are long (decadal and centennial scales) because of the infrequency of fire weather and fuel conditions. Fire return intervals are a key characteristic of fire regimes and changing fire frequencies rapidly alter land cover compositions and vegetation structure. Charcoal records from small lakes with relatively small catchments covered with dense forest provide an opportunity to reconstruct low-frequency, high-severity fires through a time series decomposition approach to identify charcoal peaks above a varying background rate as a proxy for palaeofire events. The sediment core from Rumuiku wetland on Mount Kenya, equatorial eastern Africa, accumulated a nearly linear age-depth model and provided a high temporal resolution (10 years cm -1 ) sieved charcoal count record (>125 µm). Pollen analysis showed a significant change in montane forest assemblage occurred at 21 200 cal a BP from a montane forest with abundant Podocarpus and Juniperus to a forest with more abundant Hagenia. This change in forest altered the vegetation composition and structure with concomitant changes to the fire regime. Forest biomass in the Hagenia forests decreased and it is likely that fire activity qualitatively changed toward lower intensity and lower severity fires. The quantitative fire event reconstruction focuses on the interval from 27 000 to 16 500 cal a bp and the older montane forest that experienced higher severity fires from 27 000 to 21 200 cal a BP, which reconstructed a temporally heterogeneous fire regime with fire return intervals that ranged from 30-430 years and a mean of 120 years (median 160 years) in the catchment. These are the first estimates of fire return intervals of mountain forests in eastern Africa. We then explore the potential for further comparative research and incremental research contributions to improve quantitative and qualitative palaeofire research in tropical forest ecosystems. We discuss the potential to use these types of data for characterizing variables of fire regimes prior to ostensibly significant modification by anthropogenic activity as well as during the recent past as human land use pressures increased within Afromontane forests.

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“…Few systematic studies on the reproductive ecology of individual species within this tribe have been published. However, existing evidence indicates that all kinds of pollination modes, including entomophily, anemophily, and ambophily, are present (Grímsson et al, 2021;Knuth, 1898;Seltmann et al, 2007). Therefore, Agrimonieae likely represent an excellent example to study the evolution of pollination modes.…”

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Pollination mode and reproductive system of Sanguisorba minor and Sanguisorba officinalis

Abrahamczyk

Struck

Weigend

2023

Plant Species Biology

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Reproductive systems and pollination modes (pollination by animals vs. wind) can switch within clades, and many species with an intermediate pollination mode (ambophily, pollination by animals and wind) exist. Here, we investigate the reproductive systems and pollination modes of two common Eurasian species from the Agrimonieae (Rosaceae) that occur in open habitats, Sanguisorba minor and Sanguisorba officinalis. Based on observations from literature, the flowers of both species are visited by insects, but due to flower morphology S. minor is commonly regarded as wind pollinated, while S. officinalis is classified as insect pollinated. By measuring floral traits, such as pollen grain and ovule number per flower, observing flower visitors in natural habitats as well as in the botanical gardens and conducting pollination experiments we found that the reproductive systems and pollination modes of the two species differ: Sanguisorba minor is commonly but infrequently visited by short‐tongued insects but is nevertheless exclusively wind pollinated. However, in contrast to most other wind‐pollinated species, S. minor is highly self‐compatible and even able to set seeds by autogamous selfing. Sanguisorba officinalis, on the other hand, is largely insect pollinated, but wind also contributes to seed set (⁓17% after insect exclusion). This species is able to set seeds by geitonogmous selfing but seed set is higher by outcrossing than by selfing. Thus, our study demonstrates another example of a plant species with small, open flowers arranged in large inflorescences that can be shown to be ambophilous. Further, the study will help to reconstruct the complex evolution of pollination modes in Agrimonieae (Rosaceae).

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Hagenia from the early Miocene of Ethiopia: Evidence for possible niche evolution?

Cited by 6 publications

References 104 publications

Cenozoic migration of a desert plant lineage across the North Atlantic

Cenozoic migration of a desert plant lineage across the North Atlantic

Late Pleistocene montane forest fire return interval estimates from Mount Kenya

Pollination mode and reproductive system of Sanguisorba minor and Sanguisorba officinalis

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