Speciation Clock

• Castillo-Almansa, Elvira; Mateo, Rubén G.; Galbany-Casals, Mercè; Blanco-Gavaldà, Carme; Moreyra, Lucía D. & Roquet, Cristina [Vis alle 11 forfattere av denne artikkelen] (2026). Climate change vulnerability of the Afrotemperate flora on Africa’s tropical sky islands. Biodiversity and Conservation. ISSN 0960-3115. 35. doi: 10.1007/s10531-026-03422-9. Fulltekst i vitenarkiv Vis sammendrag

  Climate change poses a significant threat to the Afrotemperate flora of the Eastern Afromontane Biodiversity Hotspot, particularly to species confined to high-elevation ecosystems such as those found on the African sky islands. This study evaluates the vulnerability of tropical Afroalpine and Afromontane Helichrysum taxa (Compositae) by assessing their climatic niches and predicting future shifts in distribution, range fragmentation, and altitudinal limits under climate change scenarios. Occurrence records for 14 taxa (eight Afroalpine and six Afromontane) were obtained from recent field campaigns, biodiversity databases and herbaria. Ensemble ecological niche models were developed combining Generalized Linear Models, Generalized Boosting Models, and Random Forest. Taxon-specific bioclimatic variables were selected after correlation analyses. The models were calibrated using current climate data and projected using the PSL-CM6A-LR and MRI-ESM2.0 climate models with both low- and high-emission scenarios. The results show that most Afrotemperate taxa currently occupy only a portion of their climatically suitable habitat, often in geographically distant areas. Future projections indicate significant range contractions and increased fragmentation. Afroalpine taxa could lose 50–66% of their suitable habitat, while Afromontane taxa could decline by 53–79%. Suitable areas were estimated to shift upwards in elevation, with limited potential for colonization of new areas, and with no significant latitudinal or longitudinal shifts. These findings represent the first continental-scale assessment of the impact of climate change on the Afrotemperate flora using ecological niche modelling. The projected climate-induced range losses and increased habitat fragmentation, in particular combined with increasing anthropogenic pressure in this region, highlight the urgent need for targeted conservation actions.

• Kandziora, Martha; Vásquez, Diana L. A.; Brochmann, Christian; Gizaw, Abel; Gustafsson, A Lovisa S & Gelete, Desalegn Chala [Vis alle 11 forfattere av denne artikkelen] (2025). The Overlooked Link Between Different Resource Partitioning Strategies and Plant Species Richness in Tropical Alpine Ecosystems. Global Ecology and Biogeography. ISSN 1466-822X. 34(12). doi: 10.1111/geb.70169. Fulltekst i vitenarkiv Vis sammendrag

  Aim Species coexistence is based on resource partitioning and modulates biodiversity patterns across climates, latitudes and altitudes. Resource partitioning can occur via niche size or separation in the geographic range or ecological niche. While resource partitioning promotes biodiversity, the impact of different partitioning strategies on species richness remains largely unexplored. Location Two ecosystems with similar climates and ages are the species‐rich tropical alpine ecosystem in the South American Andes and the more species‐poor tropical alpine ecosystem in the eastern African mountains. Time Period Present‐day distribution and climatic conditions, integrating phylogenetic information extending back to the last 7 million years maximum. Major Taxa Studied Six lineages from the Asterales; three in each ecosystem, respectively. Methods We test whether geographic range and climatic niche partitioning strategies may explain differences in species richness between two ecosystems. We combine phylogenomic data with occurrence records and estimate metrics of size and overlap for climatic niche and geographic range. Results We show that the Andean species have larger climatic niches than the African species, suggesting that niche size is not explaining higher species richness in the Andes. Instead, a striking pattern for species with overlapping geographic ranges emerged: the Andean species show less climatic niche overlap than the African species, indicating more effective niche separation among Andean species. Main Conclusions We hypothesise that differences in resource partitioning, specifically increased niche separation among geographically overlapping species in the Andes compared to the eastern African mountains, contribute to the species richness difference between these tropical alpine biodiversity hotspots.

• Brochmann, Christian; Elphinstone, Cassandra; Birkeland, Siri; Ikeda, Hajime; Eidesen, Pernille Bronken & Alsos, Inger G. [Vis alle 7 forfattere av denne artikkelen] (2025). Phylogeography of Arctic plants: where are we after 35 years, and where to go? Plant Ecology & Diversity. ISSN 1755-0874. 18(3-4), s. 99–123. doi: 10.1080/17550874.2025.2571098. Fulltekst i vitenarkiv Vis sammendrag

  Background The Arctic provides an excellent system to study climate change effects on geographic ranges and genetic diversity. We re-examine the large number of phylogeographic studies of Arctic plants to assess general patterns and identify knowledge gaps. Aims To synthesise advances and address century-old controversies, e.g. is it necessary to invoke separate glacial refugia to explain Arctic disjunctions? Methods We undertook a literature survey of the phylogeography of Arctic vascular plants. Results We provide a list of 88 taxa studied, representing a striking diversity of phylogeographic histories. In many widespread species, recent trans-oceanic long-distance dispersal (LDD) is sufficient to explain disjunctions, but three rare species show clear signals of separate Scandinavian and American glacial refugia. The extreme bipolar disjunctions are apparently caused by Plio-Pleistocene LDDs. Beringia and western Siberia have served as long-standing northern refugia; in contrast, North Atlantic areas harbour much less genetic diversity and distinctiveness. The genomic era is now providing evidence for multiple refugia from modern and ancient DNA and demonstrating that selfing leads to high biological species diversity within taxonomically recognised species. Conclusions More extensive sampling, reference genomes, and population genomic studies are required for in-depth understanding of past distributions, dispersal routes, and ability to track ongoing climate change.

• Moreyra, Lucía D.; Calleja, Juan Antonio; Roquet, Cristina; Birkeland, Siri; Blanco‐Gavaldà, Carme & Galbany‐Casals, Mercè [Vis alle 10 forfattere av denne artikkelen] (2025). Hidden lineages in the African Sky Islands: A taxonomic reevaluation of Afrocarduus (Compositae). Journal of Systematics and Evolution. ISSN 1674-4918. doi: 10.1111/jse.70024. Fulltekst i vitenarkiv Vis sammendrag

  Accurate species delimitation is crucial for biodiversity research, as it significantly impacts taxonomy, ecology, and conservation. Recent advances in molecular phylogenetics and integrative taxonomy have improved classifications and resolved long‐standing taxonomic uncertainties. Here, we use Hyb‐Seq (489 nuclear loci) and phylogenomic approaches to investigate Afrocarduus , a genus endemic to tropical Afromontane and Afroalpine regions. Our analyses reveal 16 evolutionary lineages within this relatively young genus (crown age 2.3 Mya), with new morphological data strongly supporting the recognition of each lineage as a distinct species. We demonstrate that the stemless habit evolved independently in species from the Ethiopian Highlands and the East African Rift System (EARS). Notably, we show that the concept of the stemless Afrocarduus schimperi adopted by the Flora of Tropical East Africa, in fact, comprises seven clearly recognizable species, which we formally reinstate. Unexpectedly, the stemmed Afrocarduus nyassanus was recovered as paraphyletic with Afrocarduus ruwenzoriensis nested within it, probably due to incomplete lineage sorting or hybridization. Additionally, the stemmed Afrocarduus keniensis may represent a complex of cryptic species, and we describe a new stemmed species from southern Ethiopia, Afrocarduus kazmi sp. nov. We expand the number of accepted species in Afrocarduus from eight, as recognized in the Flora of Tropical East Africa, to 18 (including two species for which we were not able to obtain molecular data). Our study thus highlights a substantial prior underestimation of the diversity of Afrocarduus in Afromontane and Afroalpine habitats.

• Moreyra, Lucía D.; Roquet, Cristina; Susanna, Alfonso; Birkeland, Siri; Blanco‐Gavaldà, Carme & Brochmann, Christian [Vis alle 10 forfattere av denne artikkelen] (2025). From Pleistocene Corridors to Isolated Peaks and Back: Biogeography of Afrocarduus (Compositae) in the Afromontane Archipelago. Journal of Biogeography. ISSN 0305-0270. 52(11). doi: 10.1111/jbi.70045. Fulltekst i vitenarkiv Vis sammendrag

  Aim We investigated the biogeographic history and diversification dynamics of Afrocarduus, an Afromontane–Afroalpine genus endemic to eastern Africa. We aimed to assess the roles of geographic isolation, habitat transitions, and ecological speciation in shaping current diversity. Location The Afromontane and Afroalpine regions of East Africa and Ethiopia are situated along the Great Rift Valley system. Taxon Afrocarduus (Compositae: Carduinae), a genus comprising 18 endemic species. Methods We conducted a comprehensive taxonomic and geographic sampling of Afrocarduus, generating data from 489 nuclear loci. Phylogenomic and biogeographic ancestral estimation analyses were performed to infer the evolutionary history and historical biogeography of the genus. Results Afrocarduus originated in the Afromontane zone of eastern Africa during the Late Miocene (~10.7 Ma), with major diversification events occurring in the Early Pleistocene (~2.3 Ma). Most dispersal events occurred between neighbouring massifs, though occasional long-distance dispersal between disjunct mountain systems was detected. The Turkana Depression and the Great Rift Valley have acted as major biogeographic barriers. Phylogenetic structure shows distinct clades occupying different regions. Ecological divergence between Afromontane and Afroalpine environments contributed to speciation, with at least six independent adaptations to Afroalpine conditions and multiple cases of ecological reversal. Stem loss, a trait associated with alpine habitats, evolved convergently in two clades. Closely related species often segregate by elevation or microhabitat within the same massif. Main Conclusions The diversification of Afrocarduus has been shaped by a combination of historical climate change, geographic isolation, and ecological adaptation. Our results emphasise the importance of ecological speciation and habitat transitions in Afrotemperate plant evolution and highlight the need for further research on understudied Afromontane taxa, especially under the threat of ongoing climate change.

• Gorospe, Juan Manuel; Zaveska, Eliska; Chala, Desalegn; Seid, Abel Gizaw; Tusiime, Felly Mugizi & Gustafsson, A Lovisa S [Vis alle 10 forfattere av denne artikkelen] (2025). Ecological speciation with gene flow followed initial large-scale geographic speciation in the enigmatic afroalpine giant senecios (Dendrosenecio). New Phytologist. ISSN 0028-646X. 246(5), s. 2307–2323. doi: 10.1111/nph.20432. Fulltekst i vitenarkiv Vis sammendrag

  Mountains have highly heterogeneous environments that generate ample opportunities for lineage differentiation through ecological adaptation, geographic isolation and secondary contact. The geographic and ecological isolation of the afroalpine vegetation fragments on the East African mountain tops makes them an excellent system to study speciation. The initial diversification within the afroalpine endemic genus Dendrosenecio was shown to occur via allopatric divergence among four isolated mountain groups, but the potential role of ecological speciation within these groups and the role of gene flow in speciation remained uncertain. Here we extend the sampling of Dendrosenecio and use phylogenomics to assess the importance of gene flow in the diversification of the genus. Then, population genomics, demographic modelling and habitat differentiation analyses are used to study ecological speciation in two sister species occurring on Mount Kenya. We found that two sympatric sister species on Mt Kenya occupy distinct microhabitats, and our analyses support that they originated in situ via ecological speciation with gene flow. In addition, we obtained signals of admixture history between mountain groups. Taken together, these results suggest that geographic isolation shaped main lineages, while ecologically mediated speciation occurred within a single mountain.

• Seid, Abel Gizaw; Dimitrov, Dimitar; Masao, Catherine Aloyce; Tusiime, Felly Mugizi; Woldimu, Tigist & Abdi, Ahmed Abdikadir [Vis alle 22 forfattere av denne artikkelen] (2025). Genetic Diversity Is Not Correlated With Species Diversity: A Multispecies Study in a Continental Habitat Island System. Journal of Biogeography. ISSN 0305-0270. 52(9). doi: 10.1111/jbi.15185. Fulltekst i vitenarkiv Vis sammendrag

  Aim It has been proposed that species diversity (SD) and genetic diversity (GD) co-vary across natural communities because both are shaped by processes such as immigration and drift. However, empirical reports are contradictory, and multispecies studies are rare. Here we test the hypothesis that the two diversity measures do not correlate in systems with high levels of immigration stochasticity and little GD caused by strong genetic drift. Location Tropical alpine habitats on six of the highest mountains in eastern Africa. Taxon Vascular plants. Methods We sampled 375 taxa in 75 plots in five habitat types, recorded ecological variables, and genotyped 1793 plants representing 20 species/species complexes. Results We confirmed that intrapopulation GD was exceptionally low in this system and found that most Species-Genetic Diversity Correlations (SGDCs) were weak and insignificant. Whereas SD was correlated with several environmental variables, GD was only correlated with mountain identity (geographical location) and mountain age. Main Conclusions Our findings support the hypothesis that SGDCs are lacking in habitat island systems such as the tropical alpine region in Africa, which is characterised by frequent population size fluctuations, extinctions, and colonisations via long-distance dispersal (LDD) during the glacial cycles. The stochastic nature of LDD combined with strong genetic drift and founder effects is likely to cause low GD and lack of SGDCs, implying that SD cannot be used as a proxy for GD in conservation management of such systems.

• Moreyra, Lucía D.; Susanna, Alfonso; Calleja, Juan Antonio; Ackerfield, Jennifer R.; Arabacı, Turan & Blanco-Gavaldà, Carme [Vis alle 19 forfattere av denne artikkelen] (2025). A thorny tale: The origin and diversification of Cirsium (Compositae). Molecular Phylogenetics and Evolution. ISSN 1055-7903. 204. doi: 10.1016/j.ympev.2025.108285. Fulltekst i vitenarkiv Vis sammendrag

  Widely distributed plant genera offer insights into biogeographic processes and biodiversity. The Carduus-Cirsium group, with over 600 species in eight genera, is diverse across the Holarctic regions, especially in the Mediterranean Basin, Southwest Asia, Japan, and North America. Despite this diversity, evolutionary and biogeographic processes within the group, particularly for the genus Cirsium, remain underexplored. This study examines the biogeographic history and diversification of the group, focusing on Cirsium, using the largest molecular dataset for the group (299 plants from 251 taxa). Phylogenomic analyses based on 350 nuclear loci, derived from target capture sequencing, revealed highly resolved and consistent phylogenetic trees, with some incongruences likely due to hybridization and incomplete lineage sorting. Ancestral range estimations suggest that the Carduus-Cirsium group originated during the Late Miocene in the Western Palearctic, particularly in the Mediterranean, Eastern Europe, or Southwest Asia. A key dispersal event to tropical eastern Africa around 10.7 million years ago led to the genera Afrocarduus and Afrocirsium, which later diversified in the Afromontane region. The two subgenera of Cirsium—Lophiolepis and Cirsium—began diversifying around 7.2–7.3 million years ago in the Western Palearctic. During the Early Pliocene, diversification rates increased, with both subgenera dispersing to Southwest Asia, where extensive in situ diversification occurred. Rapid radiations in North America and Japan during the Pleistocene were triggered by jump-dispersals events from Asia, likely driven by geographic isolation and ecological specialization. This added further layers of complexity to the already challenging taxonomic classification of Cirsium.Keywords: Biogeography; Carduinae; Cirsium; Diversification; North Hemisphere; Target-enrichment; Taxonomy.

• Marie-Orleach, Lucas; Glémin, Sylvain; Brandrud, Marie Kristine; Brysting, Anne Krag; Seid, Abel Gizaw & Gustafsson, A Lovisa S [Vis alle 9 forfattere av denne artikkelen] (2024). How Does Selfing Affect the Pace and Process of Speciation? Cold Spring Harbor Perspectives in Biology. 16(11). doi: 10.1101/cshperspect.a041426. Fulltekst i vitenarkiv Vis sammendrag

  Surprisingly little attention has been given to the impact of selfing on speciation, even though selfing reduces gene flow between populations and affects other key population genetics parameters. Here we review recent theoretical work and compile empirical data from crossing experiments and genomic and phylogenetic studies to assess the effect of mating systems on the speciation process. In accordance with theoretical predictions, we find that accumulation of hybrid incompatibilities seems to be accelerated in selfers, but there is so far limited empirical support for a predicted bias toward underdominant loci. Phylogenetic evidence is scarce and contradictory, including studies suggesting that selfing either promotes or hampers speciation rate. Further studies are therefore required, which in addition to measures of reproductive barrier strength and selfing rate should routinely include estimates of demographic history and genetic divergence as a proxy for divergence time.

• Blanco-Gavaldà, Carme; Galbany-Casals, Mercè; Susanna, Alfonso; Andrés-Sánchez, Santiago; Bayer, Randall J. & Brochmann, Christian [Vis alle 19 forfattere av denne artikkelen] (2023). Repeatedly Northwards and Upwards: Southern African Grasslands Fuel the Colonization of the African Sky Islands in Helichrysum (Compositae). Plants. 12(11). doi: 10.3390/plants12112213. Fulltekst i vitenarkiv
• Moreyra, Lucía D.; Garcia-Jacas, Núria; Roquet, Cristina; Ackerfield, Jennifer R.; Arabacı, Turan & Blanco-Gavaldà, Carme [Vis alle 20 forfattere av denne artikkelen] (2023). African Mountain Thistles: Three New Genera in the Carduus-Cirsium Group. Plants. 12(17). doi: 10.3390/plants12173083. Fulltekst i vitenarkiv
• Birkeland, Siri (2022). To what degree does hybridization facilitate evolutionary radiations in mountain areas? National Science Review. ISSN 2095-5138. 9(nwac288). Fulltekst i vitenarkiv
• Fashing, Peter; Nguyen, Nga; Demissew, Sebsebe; Gizaw, Abel; Atickem, Anagaw Meshesha & Mekonnen, Addisu [Vis alle 9 forfattere av denne artikkelen] (2022). Ecology, evolution, and conservation of Ethiopia’s biodiversity. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 119(50). doi: 10.1073/pnas.2206635119. Fulltekst i vitenarkiv Vis sammendrag

  Ethiopia is home to one of the richest and most unique assemblages of fauna and flora on the African continent. Contained within its borders are two major centers of endemism, the mesic Roof of Africa (also known as the Ethiopian Highlands) and the arid Horn of Africa, resulting from the country’s varied topography and consequent geographic isolation. These centers of endemism are crucial to global conservation as evidenced by their classification within the Eastern Afromontane and Horn of Africa biodiversity hotspots, respectively. Ethiopia’s diverse ecosystems and the biodiversity they contain are increasingly threatened by climate change and the growing impacts of Africa’s second largest human and largest livestock populations. In this paper, we focus on several key areas of recent and ongoing research on Ethiopian biodiversity that have broadened our understanding of nature and its conservation in Africa. Topics explored include the behavioral ecology of Ethiopia’s large social mammals, the ecology and conservation of its unique coffee forests, and Ethiopian approaches to community conservation, fortress conservation, and nature-based solutions. We also highlight the increasing prominence of Ethiopian scientists in studies of the country’s biodiversity in recent decades. We suggest promising avenues for future research in evolutionary biology, ecology, systematics, and conservation in Ethiopia and discuss how recent and ongoing work in Ethiopia is helping us better understand and conserve nature in the human-dominated landscapes of Africa and other tropical regions today.

• Kandziora, Martha; Gehrke, Berit; Popp, Magnus; Gizaw, Abel; Brochmann, Christian & Pirie, Michael David (2022). The enigmatic tropical alpine flora on the African sky islands is young, disturbed, and unsaturated. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 119(22). doi: 10.1073/pnas.2112737119. Fulltekst i vitenarkiv Vis sammendrag

  Tropical alpine floras are renowned for high endemism, spectacular giant rosette plants testifying to convergent adaptation to harsh climates with nightly frosts, and recruitment dominated by long-distance dispersal from remote areas. In contrast to the larger, more recent (late Miocene onward) and contiguous expanses of tropical alpine habitat in South America, the tropical alpine flora in Africa is extremely fragmented across small patches on distant mountains of variable age (Oligocene onward). How this has affected the colonization and diversification history of the highly endemic but species-poor afroalpine flora is not well known. Here we infer phylogenetic relationships of ∼20% of its species using novel genome skimming data and published matrices and infer a timeframe for species origins in the afroalpine region using fossil-calibrated molecular clocks. Although some of the mountains are old, and although stem node ages may substantially predate colonization, most lineages appear to have colonized the afroalpine during the last 5 or 10 My. The accumulation of species increased exponentially toward the present. Taken together with recent reports of extremely low intrapopulation genetic diversity and recent intermountain population divergence, this points to a young, unsaturated, and dynamic island scenario. Habitat disturbance caused by the Pleistocene climate oscillations likely induced cycles of colonization, speciation, extinction, and recolonization. This study contributes to our understanding of differences in the histories of recruitment on different tropical sky islands and on oceanic islands, providing insight into the general processes shaping their remarkable floras.

• Marie-Orleach, Lucas; Brochmann, Christian & Glémin, Sylvain (2022). Mating system and speciation I: Accumulation of genetic incompatibilities in allopatry. PLoS Genetics. ISSN 1553-7390. 18(12). doi: 10.1371/journal.pgen.1010353. Fulltekst i vitenarkiv Vis sammendrag

  Self-fertilisation is widespread among hermaphroditic species across the tree of life. Selfing has many consequences on the genetic diversity and the evolutionary dynamics of populations, which may in turn affect macroevolutionary processes such as speciation. On the one hand, because selfing increases genetic drift and reduces migration rate among populations, it may be expected to promote speciation. On the other hand, because selfing reduces the efficacy of selection, it may be expected to hamper ecological speciation. To better understand under which conditions and in which direction selfing affects the build-up of reproductive isolation, an explicit population genetics model is required. Here, we focus on the interplay between genetic drift, selection and genetic linkage by studying speciation without gene flow. We test how fast populations with different rates of selfing accumulate mutations leading to genetic incompatibilities. When speciation requires populations to pass through a fitness valley caused by underdominant and compensatory mutations, selfing reduces the depth and/or breadth of the valley, and thus overall facilitates the fixation of incompatibilities. When speciation does not require populations to pass through a fitness valley, as for Bateson-Dobzhanzky-Muller incompatibilities (BDMi), the lower effective population size and higher genetic linkage in selfing populations both facilitate the fixation of incompatibilities. Interestingly, and contrary to intuitive expectations, local adaptation does not always accelerate the fixation of incompatibilities in outcrossing relative to selfing populations. Our work helps to clarify how incompatibilities accumulate in selfing vs . outcrossing lineages, and has repercussions on the pace of speciation as well as on the genetic architecture of reproductive isolation.

• Birkeland, Siri; Slotte, Tanja; Brysting, Anne Krag; Gustafsson, Lovisa; Hvidsten, Torgeir Rhoden & Brochmann, Christian [Vis alle 7 forfattere av denne artikkelen] (2022). What can cold-induced transcriptomes of Arctic Brassicaceae tell us about the evolution of cold tolerance? Molecular Ecology. ISSN 0962-1083. 31(16), s. 4271–4285. doi: 10.1111/mec.16581. Fulltekst i vitenarkiv Vis sammendrag

  Little is known about the evolution of cold tolerance in polar plant species and how they differ from temperate relatives. To gain insight into their biology and the evolution of cold tolerance, we compared the molecular basis of cold response in three Arctic Brassicaceae species. We conducted a comparative time series experiment to examine transcriptional responses to low temperature. RNA was sampled at 22°C, and after 3, 6, and 24 at 2°C. We then identified sets of genes that were differentially expressed in response to cold and compared them between species, as well as to published data from the temperate Arabidopsis thaliana. Most differentially expressed genes were species-specific, but a significant portion of the cold response was also shared among species. Among thousands of differentially expressed genes, ~200 were shared among the three Arctic species and A. thaliana, while ~100 were exclusively shared among the three Arctic species. Our results show that cold response differs markedly between Arctic Brassicaceae species, but probably builds on a conserved basis found across the family. They also confirm that highly polygenic traits such as cold tolerance may show little repeatability in their patterns of adaptation.

• Mairal, Mario; Namaganda, Mary; Gizaw, Abel; Chala, Desalegn; Brochmann, Christian & Catalan, Pilar (2021). Multiple mountain-hopping colonization of sky-islands on the two sides of Tropical Africa during the Pleistocene: The afroalpine Festuca grasses. Journal of Biogeography. ISSN 0305-0270. doi: 10.1111/jbi.14117. Fulltekst i vitenarkiv
• Brochmann, Christian; Gizaw, Abel; Chala, Desalegn; Kandziora, Martha; Eilu, Gerald & Popp, Magnus [Vis alle 8 forfattere av denne artikkelen] (2021). History and evolution of the afroalpine flora: in the footsteps of Olov Hedberg. Alpine Botany. ISSN 1664-2201. doi: 10.1007/s00035-021-00256-9. Fulltekst i vitenarkiv Vis sammendrag

  The monumental work of Olov Hedberg provided deep insights into the spectacular and fragmented tropical alpine flora of the African sky islands. Here we review recent molecular and niche modelling studies and re-examine Hedberg’s hypotheses and conclusions. Colonisation started when mountain uplift established the harsh diurnal climate with nightly frosts, accelerated throughout the last 5 Myr (Plio-Pleistocene), and resulted in a flora rich in local endemics. Recruitment was dominated by long-distance dispersals (LDDs) from seasonally cold, remote areas, mainly in Eurasia. Colonisation was only rarely followed by substantial diversification. Instead, most of the larger genera and even species colonised the afroalpine habitat multiple times independently. Conspicuous parallel evolution occurred among mountains, e.g., of gigantism in Lobelia and Dendrosenecio and dwarf shrubs in Alchemilla. Although the alpine habitat was ~ 8 times larger and the treeline was ~ 1000 m lower than today during the Last Glacial Maximum, genetic data suggest that the flora was shaped by strong intermountain isolation interrupted by rare LDDs rather than ecological connectivity. The new evidence points to a much younger and more dynamic island scenario than envisioned by Hedberg: the afroalpine flora is unsaturated and fragile, it was repeatedly disrupted by the Pleistocene climate oscillations, and it harbours taxonomic and genetic diversity that is unique but severely depauperated by frequent bottlenecks and cycles of colonisation, extinction, and recolonisation. The level of intrapopulation genetic variation is alarmingly low, and many afroalpine species may be vulnerable to extinction because of climate warming and increasing human impact.

• Gustafsson, A Lovisa S; Gussarova, Galina; Borgen, Liv; Ikeda, Hajime; Antonelli, Alexandre & Marie-Orleach, Lucas [Vis alle 8 forfattere av denne artikkelen] (2021). Rapid evolution of post-zygotic reproductive isolation is widespread in Arctic plant lineages. Annals of Botany. ISSN 0305-7364. 129(2), s. 171–184. doi: 10.1093/aob/mcab128. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Background and Aims The Arctic tundra, with its extreme temperatures and short growing season, is evolutionarily young and harbours one of the most species-poor floras on Earth. Arctic species often show little phenotypic and genetic divergence across circumpolar ranges. However, strong intraspecific post-zygotic reproductive isolation (RI) in terms of hybrid sterility has frequently evolved within selfing Arctic species of the genus Draba. Here we assess whether incipient biological species are common in the Arctic flora. Methods We conducted an extensive crossing experiment including six species representing four phylogenetically distant families collected across the circumpolar Arctic. We crossed conspecific parental populations representing different spatial scales, raised 740 F1 hybrids to maturity and measured fertility under laboratory conditions. We examined genetic divergence between populations for two of these species (Cardamine bellidifolia and Ranunculus pygmaeus). Key Results In five of the six species, we find extensive reduction in pollen fertility and seed set in F1 hybrids; 219 (46 %) of the 477 F1 hybrids generated between parents separated by ≥427 km had <20 % pollen fertility. Isolation with migration (IM) and *BEAST analyses of sequences of eight nuclear genes in C. bellidifolia suggests that reproductively isolated populations of this species diverged during, or even after, the last glaciation. Likewise, Arctic populations of R. pygmaeus were genetically very similar despite exhibiting strongly reduced fertility in crosses, suggesting that RI evolved recently also in this species. Conclusion We show that post-zygotic RI has developed multiple times within taxonomically recognized Arctic species belonging to several distantly related lineages, and that RI may have developed over just a few millennia. Rapid and widespread evolution of incipient biological species in the Arctic flora might be associated with frequent bottlenecks due to glacial cycles, and/or selfing mating systems, which are common in the harsh Arctic environment where pollinators are scarce.

• Gizaw, Abel; Gorospe, Juan Manuel; Kandziora, Martha; Chala, Desalegn; Gustafsson, A Lovisa S & Zergabachew, Abush Zinaw [Vis alle 11 forfattere av denne artikkelen] (2021). Afro-alpine flagships revisited II: elucidating the evolutionary relationships and species boundaries in the giant senecios (Dendrosenecio, Asteraceae). Alpine Botany. ISSN 1664-2201. doi: 10.1007/s00035-021-00268-5. Fulltekst i vitenarkiv Vis sammendrag

  Alpine plant radiations are common across all major mountain systems of the world, and have been regarded as the main explanation for the species diversity found within these areas. To study the mechanisms behind the origin of this diversity, it is necessary to determine phylogenetic relationships and species boundaries in radiating alpine groups. The genus Dendrosenecio (Asteraceae) is an iconic example of a tropical-alpine plant radiation in the East African high mountains. To this date, limited sampling of molecular markers has resulted in insufficient phylogenetic resolution and infrageneric classification, hindering a comprehensive understanding of the drivers of diversification. Here, we used Hyb-Seq and the Compositae1061 probe set to generate targeted nuclear and off-target plastid DNA data for 42 samples representing all currently accepted 11 species. We combined coalescent methods and paralogy analysis to infer phylogenetic relationships, estimate divergence times and evaluate species boundaries. Lineage differentiation in Dendrosenecio seems to have occurred between the Late Miocene and the Pleistocene, starting when the first high elevation habitats became available in East Africa. We retrieved four major clades corresponding to four geographically distant mountain groups, testifying the importance of allopatric speciation in the early diversification of the group. Cytonuclear discordance suggested the occurrence of historical hybridization following occasional long-distance dispersal between mountain groups. The species delimitation analysis favored 10 species, but only five were fully supported, suggesting that population-level studies addressing processes such as ecological speciation and hybridization after secondary contact are needed to determine the current diversity found in the genus.

• Tusiime, Felly Mugizi; Seid, Abel Gizaw; Gusarova, Galina; Nemomissa, Sileshi; Popp, Magnus & Mirre, Virginia [Vis alle 12 forfattere av denne artikkelen] (2020). Afro-alpine flagships revisited: Parallel adaptation, intermountain admixture and shallow genetic structuring in the giant senecios (Dendrosenecio). PLOS ONE. 15(3), s. 1–22. doi: 10.1371/journal.pone.0228979. Fulltekst i vitenarkiv Vis sammendrag

  Distantly related lineages of the enigmatic giant rosette plants of tropical alpine environments provide classical examples of convergent adaptation. For the giant senecios (<i>Dendrosenecio</i>), the endemic landmarks of the East African sky islands, it has also been suggested that parallel adaptation has been important for within-lineage differentiation. To test this hypothesis and to address potential gene flow and hybridization among the isolated sky islands, we organized field expeditions to all major mountains. We sampled all currently accepted species and all but one subspecies and genotyped 460 plants representing 109 populations. We tested whether genetic structuring corresponds to geography, as predicted by a parallel adaptation hypothesis, or to altitudinal belt and habitat rather than mountains, as predicted by a hypothesis of a single origin of adaptations. Bayesian and Neighbor-Net analyses showed that the main genetic structure is shallow and largely corresponds to geography, supporting a hypothesis of recent, rapid radiation via parallel altitude/habitat adaptation on different mountains. We also found evidence for intermountain admixture, suggesting several long-distance dispersals by wind across vast areas of unsuitable habitat. The combination of parallel adaptation, secondary contact, and hybridization may explain the complex patterns of morphological variation and the contradicting taxonomic treatments of these rare enigmatic giants, supporting the use of wide taxonomic concepts. Notably, the within-population genetic diversity was very low and calls for increased conservation efforts.

• Nowak, Michael; Birkeland, Siri; Mandáková, Terezie; Choudhury, Rimjhim Roy; Guo, Xinyi & Gustafsson, A Lovisa S [Vis alle 15 forfattere av denne artikkelen] (2020). The genome of Draba nivalis shows signatures of adaptation to the extreme environmental stresses of the Arctic. Molecular Ecology Resources. ISSN 1755-098X. doi: 10.1111/1755-0998.13280. Fulltekst i vitenarkiv
• Birkeland, Siri; Gustafsson, A Lovisa S; Brysting, Anne Krag; Brochmann, Christian & Nowak, Michael (2020). Multiple Genetic Trajectories to Extreme Abiotic Stress Adaptation in Arctic Brassicaceae. Molecular Biology and Evolution (MBE). ISSN 0737-4038. 37(7), s. 2052–2068. doi: 10.1093/molbev/msaa068. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Extreme environments offer powerful opportunities to study how different organisms have adapted to similar selection pressures at the molecular level. Arctic plants have adapted to some of the coldest and driest biomes on Earth and typically possess suites of similar morphological and physiological adaptations to extremes in light and temperature. Here, we compare patterns of molecular evolution in three Brassicaceae species that have independently colonized the Arctic and present some of the first genetic evidence for plant adaptations to the Arctic environment. By testing for positive selection and identifying convergent substitutions in orthologous gene alignments for a total of 15 Brassicaceae species, we find that positive selection has been acting on different genes, but similar functional pathways in the three Arctic lineages. The positively selected gene sets identified in the three Arctic species showed convergent functional profiles associated with extreme abiotic stress characteristic of the Arctic. However, there was little evidence for independently fixed mutations at the same sites and for positive selection acting on the same genes. The three species appear to have evolved similar suites of adaptations by modifying different components in similar stress response pathways, implying that there could be many genetic trajectories for adaptation to the Arctic environment. By identifying candidate genes and functional pathways potentially involved in Arctic adaptation, our results provide a framework for future studies aimed at testing for the existence of a functional syndrome of Arctic adaptation in the Brassicaceae and perhaps flowering plants in general.

• Andermann, Tobias; Jiménez, Maria Fernanda Torres; Matos-Maravi, Pável; Batista, Romina; Blanco-Pastor, José L. & Gustafsson, A Lovisa S [Vis alle 11 forfattere av denne artikkelen] (2020). A guide to carrying out a phylogenomic target sequence capture project. Frontiers in Genetics. 10:1407, s. 1–20. doi: 10.3389/fgene.2019.01407. Fulltekst i vitenarkiv

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• Kandziora, Martha; Brochmann, Christian; Seid, Abel Gizaw; Gustafsson, A Lovisa S & Gelete, Desalegn Chala (2025). The overlooked link between different resource partitioning strategies and plant species richness differences in tropical alpine ecosystems. Fulltekst i vitenarkiv
• Brochmann, Christian (2025). Draba in Dovre and Svalbard - the key to the discovery of rapid speciation. Fulltekst i vitenarkiv
• Brochmann, Christian (2025). Rublom (Draba) på Dovre og Svalbard: Nøkkelen til oppdagelsen av ultrarask artsdannelse. Fulltekst i vitenarkiv
• Chala, Desalegn; Seid, Abel Gizaw; Thorn, Jessica P.R.; Cuni-Sanchez, Aida; Eilu, Gerald & Demissew, Sebsebe [Vis alle 11 forfattere av denne artikkelen] (2024). The sky islands in eastern Africa: biodiversity, opportunities, and risks. I Schneiderbauer, Stefan; Pisa, Paola Fontanella; Jr., John F. Shroder, & Szarzynski, Joerg (Red.), Safeguarding Mountain Social-Ecological Systems, Vol 2 Building Transformative Resilience in Mountain Regions Worldwide. Elsevier . ISSN 9780443328244. s. 97–107. doi: 10.1016/b978-0-443-32824-4.00034-1. Fulltekst i vitenarkiv
• Marie-Orleach, Lucas; Glémin, Sylvain; Brandrud, Marie Kristine; Brysting, Anne Krag; Gustafsson, Lovisa & Seid, Abel Gizaw [Vis alle 9 forfattere av denne artikkelen] (2024). How does selfing affect the pace and process of speciation? Fulltekst i vitenarkiv
• Huseby, Lise Grønnerød; Brysting, Anne Krag; Brochmann, Christian; Gustafsson, A Lovisa S & Leppala, Johanna (2024). Testing the snowball theory on intraspecific reproductive isolation in Arabidopsis lyrata. Fulltekst i vitenarkiv
• Moreyra, Lucía D.; Ackerfield, Jennifer R.; Blanco-Gavaldà, Carme; Brochmann, Christian; Calleja, Juan Antonio & Fujikawa, Kazumi [Vis alle 10 forfattere av denne artikkelen] (2024). Insights into the evolutionary and biogeographic history of the Carduus-Cirsium group in the African Sky-Islands. Fulltekst i vitenarkiv
• Ronikier, Michal; Suchan, Tomasz; White, Dawson; Ree, Richard; Meireles, Jose & Brochmann, Christian [Vis alle 7 forfattere av denne artikkelen] (2024). Divergent lineages reveal a complex biogeographical history in the European range of the arctic-alpine keystone species Dryas octopetala. Fulltekst i vitenarkiv
• Castillo, Elvira; Galbany, Merce; Blanco-Galbalda, Carme; Brochmann, Christian; Gizaw, Abel & Chala, Desalegn [Vis alle 7 forfattere av denne artikkelen] (2024). Niche modeling under future climate change scenarios of Helichrysum (Compositae) in the African sky islands. Fulltekst i vitenarkiv
• Kandziora, Martha; Brochmann, Christian; Gizaw, Abel; Kolár, Filip & Schmickl, Roswitha (2024). Different levels of competition explain species richness differences between two biodiversity hotspots. Fulltekst i vitenarkiv
• Birkeland, Siri (2023). What drives the rapid evolution of reproductive isolation in Arctic plants? Fulltekst i vitenarkiv
• Birkeland, Siri (2023). Adaptation and Speciation in Arctic Extremophile Plants. Fulltekst i vitenarkiv
• Huseby, Lise Grønnerød (2023). How fast does the speciation clock tick in outcrossing lineages? Fulltekst i vitenarkiv
• Gustafsson, Lovisa (2023). Evolution of Reproductive Isolation in Arctic Plant Lineages (Keynote speaker). Fulltekst i vitenarkiv
• Seid, Abel Gizaw (2023). Revisiting Time-Honored Hypotheses of Plant Evolution in the Tropical African Sky Islands: In the Footsteps of Olov Hedberg. Fulltekst i vitenarkiv
• Gehrke, Berit; Brochmann, Christian; Kandziora, Martha; Popp, Magnus; Gizaw, Abel & Pirie, Michael David (2023). I Olov Hedbergs fotspor - Plantenes evolusjon i det afrikanske høyfjellet. Årbok for Universitetsmuseet i Bergen. ISSN 1893-1944. 40, s. 72–84. Fulltekst i vitenarkiv
• Gustafsson, Lovisa (2023). A surprising finding in an Arctic mustard changing the view of speciation. Fulltekst i vitenarkiv
• Birkeland, Siri; Gustafsson, A Lovisa S; Gizaw, Abel; Chala, Desalegn; Fraccasetti, Marco & Brazier, Thomas [Vis alle 13 forfattere av denne artikkelen] (2022). What drives the rapid buildup of sterility barriers in the Arctic crucifer Draba nivalis? Fulltekst i vitenarkiv
• Marie-Orleach, Lucas (2022). Quantifier les épisodes de sélection pré- et postcopulatoires. Fulltekst i vitenarkiv
• Marie-Orleach, Lucas (2022). Effects of Sexual Reproduction on Evolution: Sexual Selection, Sexual Isolation, and Self-Fertilisation. Fulltekst i vitenarkiv
• Brochmann, Christian (2022). Recent and rapid speciation at the extremes: from the Arctic to tropical alpine Africa. Fulltekst i vitenarkiv
• Marie-Orleach, Lucas; Brochmann, Christian & Glémin, Sylvain (2022). Theoretical Predictions on the Effects of Self-Fertilisation on Speciation. Fulltekst i vitenarkiv
• Kandziora, Martha; Gehrke, Berit; Popp, Magnus; Gizaw, Abel; Brochmann, Christian & Pirie, Michael David (2022). Young, disturbed, and usaturated: the enigmatic tropical alpine flora on the African sky islands. Fulltekst i vitenarkiv
• Marie-Orleach, Lucas; Brochmann, Christian & Glémin, Sylvain (2022). Theoretical Predictions on the Effects of Self-Fertilisation on Speciation. Fulltekst i vitenarkiv
• Marie-Orleach, Lucas; Brochmann, Christian & Glémin, Sylvain (2022). Mating System and Speciation: Accumulation of Genetic Incompatibilities in Allopatry. Fulltekst i vitenarkiv
• Chala, Desalegn & Brochmann, Christian (2022). Tropical ‘alpine’ habitats: improper use of the term alpine? Fulltekst i vitenarkiv
• Brochmann, Christian & Glémin, Sylvain (2022). Mating system and speciation – accumulation of genetic incompatibilities in allopatry. Fulltekst i vitenarkiv
• Seid, Abel Gizaw; Tusiime, Felly Mugizi; Gussarova, Galina; Nemomissa, Sileshi; Popp, Magnus & Masao, Catherine [Vis alle 12 forfattere av denne artikkelen] (2022). Afro-alpine flagships revisited: Parallel adaptation, intermountain admixture and shallow genetic structuring in the giant senecios (Dendrosenecio). Fulltekst i vitenarkiv
• Zergabachew, Abush Zinaw; Bräuchler, Christian; Demissew, Sebsebe; Brochmann, Christian & Seid, Abel Gizaw (2022). Taxonomy, speciation and biogeographic history of the genus Satureja s. Lat. In the tropical eastern African ‘sky-islands’. Fulltekst i vitenarkiv
• Brochmann, Christian; Seid, Abel Gizaw; Gelete, Desalegn Chala; Martha, Kandziora; Eilu, Gerald & Popp, Magnus [Vis alle 8 forfattere av denne artikkelen] (2022). History and evolution of the afroalpine flora: in the footsteps of Olov Hedberg. Fulltekst i vitenarkiv
• Chala, Desalegn (2021). Historical habitat connectivity, niche dynamics and evolution in a highly fragmented natural system, the African alpine ‘sky islands’. Fulltekst i vitenarkiv
• Gizaw, Abel; Gorospe, Juan Manuel; Kandziora, Martha; Chala, Desalegn; Gustafsson, A Lovisa S & Zinaw, Abush [Vis alle 11 forfattere av denne artikkelen] (2021). Is lack of phylogenetic resolution the hallmark of alpine radiation? Insights from the afro-alpine giants in Dendrosenecio (Senecioneae, Asteraceae). Fulltekst i vitenarkiv
• Grindeland, Helene Bråten (2021). Plantenes prevensjon mot seg selv. Biolog. ISSN 0801-0722. 39(1), s. 36–37. Fulltekst i vitenarkiv
• Danielsen, Dag Inge & Birkeland, Siri (2021). Hun avdekker arktiske planters frosne hemmeligheter. [Journal]. Titan.uio.no. Fulltekst i vitenarkiv
• Birkeland, Siri; Slotte, Tanja; Brochmann, Christian; Brysting, Anne Krag; Gustafsson, Lovisa & Nowak, Michael D (2021). What can the cold-induced transcriptomes of Arctic Brassicaceae tell us about the evolution of cold tolerance? Fulltekst i vitenarkiv
• Danielsen, Dag Inge & Birkeland, Siri (2021). Hvordan klarer plantene seg i ekstrem kulde i Arktis? [Journal]. Forskning.no. Fulltekst i vitenarkiv
• Marie-Orleach, Lucas; Brochmann, Christian & Glémin, Sylvain (2021). Mating System and Speciation – Accumulation of Genetic Incompatibilities in Allopatry. Fulltekst i vitenarkiv
• Gustafsson, A Lovisa S (2020). The Speciation Clock project How fast does the 'speciation clock' tick in selfing versus outcrossing lineages? Fulltekst i vitenarkiv
• Gustafsson, A Lovisa S (2020). Forskere forteller: På ekspedisjon til afrikanske himmeløyer. Fulltekst i vitenarkiv
• Marie-Orleach, Lucas (2020). Transitions between Sexual Systems: Understanding the Mechanisms of, and Pathways between, Dioecy, Hermaphroditism and Other Sexual Systems. The Quarterly review of biology. ISSN 0033-5770. 95(1), s. 86–86. Fulltekst i vitenarkiv
• Marie-Orleach, Lucas; Brochmann, Christian & Glémin, Sylvain (2020). How fast does the "speciation clock" tick in selfing versus outcrossing lineages? Fulltekst i vitenarkiv
• Mairal, Mario; Namaganda, Mary; Gizaw, Abel; Chala, Desalegn; Brochmann, Christian & Catalan, Pilar (2020). Multiple mountain-hopping colonization of sky-islands on the two sides of Tropical Africa during the Pleistocene: the afroalpine Festuca grasses. Fulltekst i vitenarkiv
• Chala, Desalegn (2020). Historical climate change impacts on the African 'Sky Island' ecosystems and the enigmatic plants comprised in them. Fulltekst i vitenarkiv
• Martha, Kandziora; Gehrke, Berit; Popp, Magnus; Gizaw, Abel; Brochmann, Christian & Pirie, Michael David (2020). Immigrants prevail: lessons from dating the Afroalpine flora. Fulltekst i vitenarkiv
• Brochmann, Christian (2020). How fast does the plant 'speciation clock' tick in the African Sky Islands? Fulltekst i vitenarkiv
• Marie-Orleach, Lucas (2019). Sexual selection, indirect genetic effects and speciation. Fulltekst i vitenarkiv
• Marie-Orleach, Lucas (2019). Sexual selection, indirect genetic effects and speciation. Fulltekst i vitenarkiv
• Brysting, Anne Krag (2019). Speciation and reproductive barriers. Fulltekst i vitenarkiv
• Nowak, Michael (2019). Searching for patterns of Arctic plant adaptation in the genome of Draba nivalis (Brassicaceae). Fulltekst i vitenarkiv
• Huseby, Lise Grønnerød; Nowak, Michael; Gustafsson, A Lovisa S; Brochmann, Christian & Brysting, Anne Krag (2019). How fast does the Speciation Clock tick? Fulltekst i vitenarkiv Vis sammendrag

  Species are the most fundamental unit in nature, yet we know surprisingly little about how long it takes for new, reproductively isolated species to originate and what factors influence the rate of speciation. Speciation depends on the evolution of reproductive barriers that make individuals reproductively isolated from one another. One potential factor that could impact how fast these reproductive barriers occur is mating system. It has been suggested that self-fertilization, a common mating system both in wild and cultivated plants and also found in animals, can drive the evolution of postzygotic reproductive isolation, and thus create new species. Our aim is to test whether selfing species diverge into new species faster than outcrossing species. We will therefore test the rate at which reproductive barriers occur within species with different mating systems, we will target one selfing and one outcrossing plant species and identify the number of loci responsible for reproductive isolation between populations representing different degrees of population divergence. For this project we will use two plant species, the selfer Draba nivalis and the outcrosser Arabidopsis lyrata and perform quantitative trait locus (QTL) mapping experiments aimed at identifying the number of loci responsible for reproductive isolation between populations representing different degrees of population divergence. For this we need to create intraspecific crosses and produce large F2 populations for genotyping and phenotyping. We will then test the ‘snowball effect’ in both species and compare the rate of accumulation of genes that contribute to reproductive isolation.

• Brochmann, Christian (2019). Project SpeciationClock: How fast does the plant 'speciation clock' tick in the African Sky Islands? Fulltekst i vitenarkiv
• Flood, Pádraic J; Goktay, Mehmet; Tergemina, Emmanuel; Gywenne-Evans, David; Gustafsson, A Lovisa S & Telia, Habte [Vis alle 17 forfattere av denne artikkelen] (2019). The genetic basis of convergent adaptation to altitude in Arabidopsis thaliana. Fulltekst i vitenarkiv
• Chala, Desalegn & Brochmann, Christian (2019). Tropical ‘alpine’ habitats: improper use of the term alpine? Fulltekst i vitenarkiv
• Birkeland, Siri; Gustafsson, A Lovisa S; Brysting, Anne Krag; Brochmann, Christian & Nowak, Michael (2019). Same destination, but different roads? Overarching, but limited fine-scale molecular convergence in Arctic crucifers. Fulltekst i vitenarkiv
• Gustafsson, A Lovisa S & Gizaw, Abel (2019). Speciation Clock-prosjektet: Feltarbeid i de afrikanske himmeløyer. Fulltekst i vitenarkiv
• Mairal, Mario; Namaganda, Mary; Brochmann, Christian & Catalan, Pilar (2019). Colonization and diversification of wind-dispersed Festuca grasses in afro-alpine sky islands. Fulltekst i vitenarkiv
• Brochmann, Christian (2018). Alle snakker om arter som dør ut - men hvor fort dannes nye? Arktis og afrikanske høyfjell kan gi et svar. Fulltekst i vitenarkiv
• Brochmann, Christian (2018). Fjellplanter og klima: rask artsdannelse, raske vandringer - og hvordan står det egentlig til med overvintringsteorien? Fulltekst i vitenarkiv
• Brochmann, Christian (2018). Hvordan og hvor fort oppstår nye plantearter? [Internet]. https://titan.uio.no/node/2847. Fulltekst i vitenarkiv
• Brochmann, Christian (2018). Alle snakker om arter som dør ut - men hvor fort dannes nye? Arktis og afrikanske høyfjell kan gi et svar. Fulltekst i vitenarkiv
• Gizaw, Abel & Brochmann, Christian (2018). Colonization, diversification and connectivity in the extremely fragmented African ‘Sky Island’ flora. Fulltekst i vitenarkiv
• Brochmann, Christian (2018). Hvor fort tikker artsdannelsesklokka? [Internet]. NHMs nettsider https://www.nhm.uio.no/om/aktuelle-saker/2018. Fulltekst i vitenarkiv

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