| 1. |
- Antonelli, Alexandre, 1978
(författare)
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The rise and fall of Neotropical biodiversity
- 2022
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 199:1, s. 8-24
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Tidskriftsartikel (refereegranskat)abstract
- The exceptional levels of biodiversity found today in the American tropics are the outcome of tens of millions of years of evolution, shaped by the tumultuous geological history of the region, its heterogeneous habitats, climate change, ecological interactions and, in recent millennia, human influence. Although our understanding of diversity patterns and their underlying processes grows steadily in breadth and depth, Neotropical biodiversity is rapidly breaking down. Here, I contrast the long-term evolution of Neotropical biodiversity with its recent and rapid deterioration due to anthropogenic factors. I consider the impacts of the early arrival of humans to the region and the modern intensification of land-use change (primarily driven by agriculture) and other drivers of biodiversity loss, such as direct exploitation, invasive species and climate change. Together, these threats have led to 33% of all Neotropical species for which sufficient data are available being currently threatened with extinction. I outline emerging opportunities for conservation and restoration under the post-2020 Global Biodiversity Framework and call for urgent action from the biodiversity community, for the benefit of people and nature.
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| 2. |
- Bacon, Christine D., et al.
(författare)
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Genomic and niche divergence in an Amazonian palm species complex
- 2021
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 197:4, s. 498-512
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Tidskriftsartikel (refereegranskat)abstract
- Environmental heterogeneity across the landscape can cause lineage divergence and speciation. The Geonoina macrostachys (Arecaceae) species complex has been proposed as a candidate case of ecological speciation in Amazonia due to evidence of habitat partitioning and pre-zygotic reproductive barriers between co-occurring morphotypes at a local scale. In this study, we provide a continent-wide perspective of the divergence patterns in a macrostachys by integrating data from morphological traits, target sequence capture, climate, soil and reproductive biology. A morphometric analysis revealed four morphogroups, defined by traits related to leaf shape. A coalescence-based phylogenetic analysis did not recover the morphogroups as monophyletic, indicating independent evolution of leaf shape across geographical space. We demonstrate scale-dependent habitat differentiation for two of the morphogroups, in which segregation driven mostly by climate was complete at the regional scale but incomplete at the continental scale. Contrary to previous evidence of reproductive isolation in the form of different pollinators and flowering times between sympatric G. macrostachys forms in Peru and Ecuador, these were not found in Colombia, suggesting reproductive barriers have evolved multiple times across its geographical range. Taken together, our findings suggest that ecological divergence and local adaptation is driving diversification in G. macrostachys, and that hyperdiverse regions such as Amazonia are probable arenas for ecological divergence in sympatry.
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| 3. |
- Bacon, Christine D., et al.
(författare)
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Phylogenetics of Iriarteeae (Arecaceae), cross-Andean disjunctions and convergence of clustered infructescence morphology in Wettinia
- 2016
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074. ; 182:2, s. 272-286
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Tidskriftsartikel (refereegranskat)abstract
- The Neotropical palm tribe Iriarteeae is ubiquitous in several lowland and montane biomes across northern South America, but the phylogenetic relationships among genera and species remain unresolved. A well resolved phylogenetic tree is key to exploring morphological evolution in the tribe, including striking features such as the complex and unique inflorescence structures in Wettinia. We generated data from five plastid (ndhA, petD-rpoA, psbK-trnS and trnG) and six nuclear (AG1, CISPs 4 and 5, PRK, RPB2 and WRKY21) molecular loci to infer the phylogeny. We explored the evolutionary patterns of trait evolution using the D statistic and stochastic character mapping. All genera were inferred as monophyletic and their relationships were recovered with strong to moderate support. Based on these results we synonymize the two species of Iriartella under I. setigera and resurrect Socratea montana from S. rostrata. Interspecific relationships were mostly consistent with current morphological classification. One exception concerns trait evolution in Wettinia, in which the clustered infructescence was found to have evolved at least four times. Phylogenetic signal for this trait was weak and randomly distributed across the tree, probably representing convergence. Our results provide a robust phylogenetic framework for Iriarteeae, largely corroborating current morphological classification and laying the groundwork for macroevolutionary studies in the tribe.
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| 4. |
- Bacon, Christine D., et al.
(författare)
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Species limits, geographical distribution and genetic diversity in Johannesteijsmannia (Arecaceae)
- 2016
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074. ; 182:2, s. 318-347
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Tidskriftsartikel (refereegranskat)abstract
- Four species are recognized in the understorey palm genus Johannesteijsmannia (Arecaceae), all of which occur in close geographical proximity in the Malay Peninsula. We hypothesize that overlapping distributions are maintained by a lack of gene flow among species and that segregation along morphological trait or environmental axes confers ecological divergence and, hence, defines species limits. Although some species have sympatric distributions, differentiation was detected among species in morphological and genetic data, corroborating current species delimitation. Differences in niche breadth were not found to explain the overlapping distribution and coexistence of Johannesteijsmannia spp. Four species formed over the last 3 Mya, showing that diversity accumulated within a short time frame and wide range expansion has not occurred, potentially due to a lack of time for dispersal or the evolution of traits to facilitate movement. An assessment of genetic diversity is presented and, as expected, the widest distribution in the genus harbours the highest genetic diversity.
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| 5. |
- Barrett, C. F., et al.
(författare)
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An introduction to plant phylogenomics with a focus on palms
- 2016
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074. ; 182:2, s. 234-255
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Tidskriftsartikel (refereegranskat)abstract
- Phylogenomics refers to the use of phylogenetic trees to interpret gene function and genome evolution and to the use of genome-scale data to build phylogenetic trees. The field of phylogenomics has advanced rapidly in the past decade due to the now widespread availability of next generation sequencing technologies, which themselves continue to change at a rapid pace and drive down the cost of sequencing per base pair. In this review, we discuss genomic resources available to palm biologists in the form of complete genomes (plastid, mitochondrial, nuclear) and sequenced transcriptomes, all of which can be leveraged to study non-model palm taxa. We also discuss various approaches to generating phylogenomic data in palms, such as next-generation sequencing technologies and methodological approaches that allow acquisition of large volumes of biologically and phylogenetically meaningful data without the need to sequence entire genomes (e.g. genome skimming, RAD-seq, targeted sequence capture). This review was designed for those unfamiliar with phylogenomics and associated methods, but who are interested in engaging in phylogenomics research. We discuss several considerations required for designing phylogenetic projects using genomic data, such as available computing capabilities and level of bioinformatics expertise. We then review some recent, empirical examples of palm phylogenomic studies and how they are shaping the future of palm systematics and evolutionary biology.
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| 6. |
- Barrett, C. F., et al.
(författare)
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Phylogenomics, biogeography and evolution in the American genus Brahea (Arecaceae)
- 2019
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 190:3, s. 242-259
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Tidskriftsartikel (refereegranskat)abstract
- Slow rates of molecular evolution at low taxonomic levels hamper studies of relationships among species and subsequent biogeographic and evolutionary analyses. An example is the genus Brahea, which is among the most poorly understood lineages of American palms and is characterized by a wide variety of growth forms and intermediate morphological features. We generated c. 400 kb of genome-scale data from all three genomes for the 11 currently described Brahea spp. to infer phylogenetic relationships, reconstruct ancestral growth form, estimate ancestral geographical ranges and test for niche differences among closely related species with geographical overlap. Relationships receive strong support and conform to previous subgeneric assignments, except for placement of the dwarf species B. moorei in Brahea subgenus Erythea. Our robust phylogenetic hypothesis reveals trends in growth form, including an overall increase in height in the B. armata clade and independent evolution of dwarf forms from taller ancestors in the B. pimo and B. dulcis clades. Ancestral range estimation reveals roles of dispersal (e.g. B. edulis on Guadalupe Island) and putative divergence within geographical regions in some cases (e.g. in the B. armata clade) but is equivocal in others (e.g. in the B. pimo clade). We find evidence of niche non-equivalency among species in the B. armata clade in north-western Mexico and some evidence of niche non-equivalency between B. berlandieri and B. dulcis, the former of which is synonymized under B. dulcis. Our findings have implications for the complex biogeographic history in Central America and Mexico, suggesting that divergence within regions and dispersal are the predominant processes of species diversification. Future studies should include population-level sampling across the genus, along with morphological and ecological information, to assess distinctness among species and, particularly, levels of gene flow, in an integrative fashion.
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| 7. |
- Bengtson, Annika, et al.
(författare)
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Phylogeny and evolution of the South African genus Metalasia (Asteraceae-Gnaphalieae) inferred from molecular and morphological data
- 2014
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 174:2, s. 173-198
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Tidskriftsartikel (refereegranskat)abstract
- Metalasia is a genus in tribe Gnaphalieae (Asteraceae), endemic to South Africa and with its main distribution in the Cape Floristic Region. The genus comprises 57 species and, with a number of closely related genera, it constitutes the Metalasia clade'. A species-level phylogenetic analysis is presented, based on DNA sequences from two nuclear (internal and external transcribed spacer: ITS, ETS) and two plastid (psbA-trnH, trnL-trnF) regions together with morphological data. Analyses combining molecular and morphological data attempt not only to resolve species interrelationships, but also to detect patterns in character evolution. Phylogenetic analyses corroborate our earlier study and demonstrate that Metalasia is formed of two equally sized, well-supported sister groups, one of which is characterized by papillose cypselas. The results differ greatly from earlier hypotheses based on morphology alone, as few morphological characters support the phylogenetic patterns obtained. The two clades of Metalasia do, however, appear to differ in distribution, corresponding to the different rainfall regimes of South Africa. Analyses show a few taxa to be problematic; one example is the widely distributed M.densa which appears to be an intricate species complex.
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| 8. |
- Bisang, Irene, et al.
(författare)
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Family affiliation, sex ratio and sporophyte frequency in unisexual mosses
- 2014
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 174:2, s. 163-172
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Tidskriftsartikel (refereegranskat)abstract
- Patterns of sex expression and sex ratios are key features of the life histories of organisms. Bryophytes are the only haploid-dominant land plants. In contrast with seed plants, more than half of bryophyte species are dioecious, with rare sexual expression and sporophyte formation and a commonly female-biased sex ratio. We asked whether variation in sex expression, sex ratio and sporophyte frequency in ten dioecious pleurocarpous wetland mosses of two different families was best explained by assuming that character states evolved: (1) in ancestors within the respective families or (2) at the species level as a response to recent habitat conditions. Lasso regression shrinkage identified relationships between family membership and sex ratio and sporophyte frequency, whereas environmental conditions were not correlated with any investigated reproductive trait. Sex ratio and sporophyte frequency were correlated with each other. Our results suggest that ancestry is more important than the current environment in explaining reproductive patterns at and above the species level in the studied wetland mosses, and that mechanisms controlling sex ratio and sporophyte frequency are phylogenetically conserved. Obviously, ancestry should be considered in the study of reproductive character state variation in plants.(c) 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 163-172.
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| 9. |
- Bisang, Irene, et al.
(författare)
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Sex expression and genotypic sex ratio vary with region and environment in the wetland moss Drepanocladus lycopodioides
- 2020
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 192:2, s. 421-434
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Tidskriftsartikel (refereegranskat)abstract
- Sex ratio variation is common among organisms with separate sexes. In bryophytes, sex chromosome segregation at meiosis suggests a balanced progeny sex ratio. However, most bryophyte populations exhibit female-biased phenotypic sex ratios based on the presence of reproductive structures on gametophytes. Many bryophyte populations do not form sexual organs, and genotypic sex ratio variation in such populations is mostly unknown. We tested sex expression, and phenotypic and genotypic sex ratios against environmental parameters in natural populations of the unisexual wetland moss Drepanocladus lycopodiodes at 11 sites in each of three regions in southern Sweden. We identified sex in 660 individual ramets, based on sexual structures, when present, or with a specifically designed molecular marker, when absent. All regions exhibited a female bias in phenotypic and genotypic sex ratios. Sex ratio biases and sex expression differed between regions. Sex ratios were less female-biased in larger patches. Wetter patches exhibited a stronger female bias in genotypic sex ratio and lower sex expression. This is the first evidence of environmental effects on genotypic sex ratio in mosses. A higher frequency of females in wet patches could be due to higher female resource demands for sporophyte production or higher male sensitivity to wetness. A higher incidence of females than males in moister sites aligns with female flowering plants, but differs from reproductive bryophytes in drier environments. Taken together with previous results, our data indicate that sex ratio variation and its drivers differ among species, their life histories and environments.
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| 10. |
- Bolinder, Kristina, et al.
(författare)
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From near extinction to diversification by means of ashift in pollination mechanism in the gymnosperm relict Ephedra (Ephedraceae, Gnetales)
- 2016
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 180:4, s. 461-477
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Tidskriftsartikel (refereegranskat)abstract
- Pollination in gymnosperms is usually accomplished by means of wind, but some groups are insect-pollinated. We show that wind and insect pollination occur in the morphologically uniform genus Ephedra (Gnetales). Based on field experiments over several years, we demonstrate distinct differences between two Ephedra species that grow in sympatry in Greece in pollen dispersal and clump formation, insect visitations and embryo formation when insects are denied access to cones. Ephedra distachya, nested in the core clade of Ephedra, is anemophilous, which is probably the prevailing state in Ephedra. Ephedra foeminea, sister to the remaining species of the genus, is entomophilous and pollinated by a range of diurnal and nocturnal insects. The generalist entomophilous system of E.foeminea, with distinct but infrequent insect visitations, is in many respects similar to that reported for Gnetum and Welwitschia and appears ancestral in Gnetales. The Ephedra lineage is well documented already from the Early Cretaceous, but the diversity declined dramatically during the Late Cretaceous, possibly to near extinction around the Cretaceous-Palaeogene boundary. The clade imbalance between insect- and wind-pollinated lineages is larger than expected by chance and the shift in pollination mode may explain why Ephedra escaped extinction and began to diversify again.
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