28 research outputs found
Phylogeny of Cyperaceae Based on DNA Sequence Data–a New rbcL Analysis
Since the Monocots II meeting in 1998, significant new data have been published that enhance our systematic knowledge of Cyperaceae. Phylogenetic studies in the family have also progressed steadily. For this study, a parsimony analysis was carried out using all rbcL sequences currently available for Cyperaceae, including data for two new genera. One of the four subfamilies (Caricoideae) and seven of the 14 tribes (Bisboeckelereae, Cariceae, Cryptangieae, Dulichieae, Eleocharideae, Sclerieae, Trilepideae) are monophyletic. Subfamily Mapanioideae and tribe Chrysitricheae are monophyletic if, as the evidence suggests, Hellmuthia is considered a member of Cypereae. Some other features of our analysis include: well-supported Trilepideae and Sclerieae–Bisboeckelereae clades; a possible close relationship between Cryptangieae and Schoeneae; polyphyletic tribes Schoeneae and Scirpeae; the occurrence of Cariceae within the Dulichieae–Scirpeae clade, and a strongly supported clade, representing Cyperus and allied genera in Cypereae, sister to a poorly supported Ficinia–Hellmuthia– Isolepis–Scirpoides clade. Such patterns are consistent with other studies based on DNA sequence data. One outcome may be that only two subfamilies, Mapanioideae and Cyperoideae, are recognized. Much further work is needed, with efforts carefully coordinated among researchers. The work should focus on obtaining morphological and molecular data for all genera in the family
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Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora
Background
The best documented survival responses of organisms to past climate change on short (glacial-interglacial) timescales are distributional shifts. Despite ample evidence on such timescales for local adaptations of populations at specific sites, the long-term impacts of such changes on evolutionary significant units in response to past climatic change have been little documented. Here we use phylogenies to reconstruct changes in distribution and flowering ecology of the Cape flora - South Africa's biodiversity hotspot - through a period of past (Neogene and Quaternary) changes in the seasonality of rainfall over a timescale of several million years.
Results
Forty-three distributional and phenological shifts consistent with past climatic change occur across the flora, and a comparable number of clades underwent adaptive changes in their flowering phenology (9 clades; half of the clades investigated) as underwent distributional shifts (12 clades; two thirds of the clades investigated). Of extant Cape angiosperm species, 14-41% have been contributed by lineages that show distributional shifts consistent with past climate change, yet a similar proportion (14-55%) arose from lineages that shifted flowering phenology.
Conclusions
Adaptive changes in ecology at the scale we uncover in the Cape and consistent with past climatic change have not been documented for other floras. Shifts in climate tolerance appear to have been more important in this flora than is currently appreciated, and lineages that underwent such shifts went on to contribute a high proportion of the flora's extant species diversity. That shifts in phenology, on an evolutionary timescale and on such a scale, have not yet been detected for other floras is likely a result of the method used; shifts in flowering phenology cannot be detected in the fossil record
Protecting stable biological nomenclatural systems enables universal communication: A collective international appeal
[eng] The fundamental value of universal nomenclatural systems in biology is that they enable unambiguous scientific communication. However, the stability of these systems is threatened by recent discussions asking for a fairer nomenclature, raising the possibility of bulk revision processes for “inappropriate” names. It is evident that such proposals come from very deep feelings, but we show how they can irreparably damage the foundation of biological communication and, in turn, the sciences that depend on it. There are four essential consequences of objective codes of nomenclature: universality, stability, neutrality, and transculturality. These codes provide fair and impartial guides to the principles governing biological nomenclature and allow unambiguous universal communication in biology. Accordingly, no subjective proposals should be allowed to undermine them
Framing the future for taxonomic monography: Improving recognition, support, and access
No abstract available
Extinction Risk and Diversification Are Linked in a Plant Biodiversity Hotspot
Plant extinction risks in the Cape, South Africa differ from those for
vertebrates worldwide, with young and fast-evolving plant lineages marching
towards extinction at the fastest rate, but independently of human effects
Framing the future for taxonomic monography: Improving recognition, support, and access
Taxonomic monographs synthesize biodiversity knowledge and document biodiversity change through recent and geological time for a particular organismal group, sometimes also incorporating cultural and place-based knowledge. They are a vehicle through which broader questions about ecological and evolutionary patterns and processes can be generated and answered (e.g., Muñoz Rodríguez et al., 2019). Chiefly, monography represents the foundational research upon which all biological work is based (Hamilton et al., 2021). Moreover, monography can be a pathway to developing inclusive scientific practices, engaging diverse audiences in expanding and disseminating indigenous and local knowledge and significance of place. Apart from the scientific importance of monography, these comprehensive biodiversity treatments are also crucial for policy, conservation, human wellbeing, and the sustainable use of natural resources. Taxonomic, cultural and biodiversity data within monographs aid in the implementation of law and policy, such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), the Nagoya Protocol of the Convention on Biological Diversity (Buck & Hamilton, 2011), and the International Union for Conservation of Nature (IUCN) Red List (e.g., Neo et al., 2017). While vital as a knowledge resource and tool for conservation and research, monographs are not available for many groups of organisms. This is of particular concern for organisms that are threatened with extinction, of medical or economic importance, and those organisms that have the potential to provide insight into biodiversity change over time because they are most susceptible to global change. In discussing the future of collections-based systematics, researchers have highlighted the importance of updated monographic workflows, collaborative teams, and effective ways to educate and disseminate the results of monographs to the public and scientific community (e.g., Wen et al., 2015; Grace et al., 2021). Here, we discuss how improving recognition, support, and access can lead to greater inclusivity while promoting a more active, sustainable, and collaborative outlook for monographic research. </p
Phylogeny of Cyperaceae Based on DNA Sequence Data: Current Progress and Future Prospects
Diversification into novel habitats in the Africa clade of Dioscorea (Dioscoreaceae): erect habit and elephant’s foot tubers
Background: Dioscorea is a widely distributed and highly diversified genus in tropical regions where it is represented
by ten main clades, one of which diversified exclusively in Africa. In southern Africa it is characterised by a distinct
group of species with a pachycaul or “elephant’s foot” structure that is partially to fully exposed above the substrate.
In contrast to African representatives of the genus from other clades, occurring mainly in forest or woodland, the
pachycaul taxa and their southern African relatives occur in diverse habitats ranging from woodland to open
vegetation. Here we investigate patterns of diversification in the African clade, time of transition from forest to
more open habitat, and morphological traits associated with each habitat and evaluate if such transitions have
led to modification of reproductive organs and mode of dispersal.
Results: The Africa clade originated in the Oligocene and comprises four subclades. The Dioscorea buchananii
subclade (southeastern tropical Africa and South Africa) is sister to the East African subclade, which is respectively
sister to the recently evolved sister South African (e. g., Cape and Pachycaul) subclades. The Cape and Pachycaul
subclades diversified in the east of the Cape Peninsula in the mid Miocene, in an area with complex geomorphology
and climate, where the fynbos, thicket, succulent karoo and forest biomes meet.
Conclusions: Diversification out of forest is associated with major shifts in morphology of the perennial tuber
(specifically an increase in size and orientation which presumably led them to become pachycaul) and rotation of
stem (from twining to non-twining). The iconic elephant's foot morphology, observed in grasslands and thicket
biomes, where its corky bark may offer protection against fire and herbivory, evolved since mid Miocene. A shift
in pollination trait is observed within the forest, but entry into open habitat does not show association with
reproductive morphology, except in the seed wing, which has switched from winged all round the seed margin
to just at the base or at the apex of it, or has been even replaced by an elaiosome
