Freshwater ecosystems are of worldwide importance for maintaining biodiversity and sustaining the provision of a myriad of ecosystem services to modern societies. Plants, one of the most important... Show moreFreshwater ecosystems are of worldwide importance for maintaining biodiversity and sustaining the provision of a myriad of ecosystem services to modern societies. Plants, one of the most important components of these ecosystems, are key to water nutrient removal, carbon storage, and food provision. Understanding how the functional connection between freshwater plants and ecosystems is affected by global change will be key to our ability to predict future changes in freshwater systems. Here, we synthesize global plant responses, adaptations, and feedbacks to present-day and future freshwater environments through trait-based approaches, from single individuals to entire communities. We outline the transdisciplinary knowledge benchmarks needed to further understand freshwater plant biodiversity and the fundamental services they provide. Show less
Sabatini, F.M.; Lenoir, J.; Hattab, T.; Arnst, E.A.; Chytrý, M.; Dengler, J.; ... ; Bruelheide, H. 2021
Motivation: Assessing biodiversity status and trends in plant communities is critical for understanding, quantifying and predicting the effects of global change on ecosystems. Vegetation plots... Show moreMotivation: Assessing biodiversity status and trends in plant communities is critical for understanding, quantifying and predicting the effects of global change on ecosystems. Vegetation plots record the occurrence or abundance of all plant species co-occurring within delimited local areas. This allows species absences to be inferred, information seldom provided by existing global plant datasets. Although many vegetation plots have been recorded, most are not available to the global research community. A recent initiative, called ‘sPlot’, compiled the first global vegetation plot database, and continues to grow and curate it. The sPlot database, however, is extremely unbalanced spatially and environmentally, and is not open-access. Here, we address both these issues by (a) resampling the vegetation plots using several environmental variables as sampling strata and (b) securing permission from data holders of 105 local-to-regional datasets to openly release data. We thus present sPlotOpen, the largest open-access dataset of vegetation plots ever released. sPlotOpen can be used to explore global diversity at the plant community level, as ground truth data in remote sensing applications, or as a baseline for biodiversity monitoring.Main types of variable contained: Vegetation plots (n = 95,104) recording cover or abundance of naturally co-occurring vascular plant species within delimited areas. sPlotOpen contains three partially overlapping resampled datasets (c. 50,000 plots each), to be used as replicates in global analyses. Besides geographical location, date, plot size, biome, elevation, slope, aspect, vegetation type, naturalness, coverage of various vegetation layers, and source dataset, plot-level data also include community- weighted means and variances of 18 plant functional traits from the TRY Plant Trait Database.Spatial location and grain: Global, 0.01–40,000 m2.Time period and grain: 1888–2015, recording dates.Major taxa and level of measurement: 42,677 vascular plant taxa, plot-level records. Software format: Three main matrices (.csv), relationally linked. Show less
Trigonostemon Blume is a plant genus in the family Euphorbiaceae comprising 59 species. These plants are small trees or shrubs growing in the lowland rainforests in Southeast Asia and adjacent... Show moreTrigonostemon Blume is a plant genus in the family Euphorbiaceae comprising 59 species. These plants are small trees or shrubs growing in the lowland rainforests in Southeast Asia and adjacent areas. The small unisexual flowers with colourful petals and the 3 or 5 united stamens are typical characters of the genus. The present thesis studies four aspects of the genus: the taxonomy, pollen morphology, molecular phylogeny and historical biogeography. The species delimitation has been optimised in the taxonomic revisions and the species complexes can now be clearly recognised by morphological characters. Palynological studies reveal strong correlations between pollen and macromorphology in Trigonostemon and these support the infrageneric classification of the genus. Molecular phylogenetic analyses have demonstrated that Trigonostemon and Dimorphocalyx Thwaites are two monophyletic groups and are not closely related, although they are similar in morphology. Furthermore, Trigonostemon is divided into four sections based on molecular and (pollen) morphological data. Finally, the thesis concludes with the historical biogeography of Trigonostemon: it probably originated on Southeast Asian mainland, one lineage later radiated to the Malay Peninsula, and dispersed further eastwards and diversified before the genus reached its current distribution. Show less
The general goal of this PhD research was to study the phylogeny and systematics of selected plant genera in the subfamily Acalyphoideae s.s. of the angiosperm family Euphorbiaceae. The main focus... Show moreThe general goal of this PhD research was to study the phylogeny and systematics of selected plant genera in the subfamily Acalyphoideae s.s. of the angiosperm family Euphorbiaceae. The main focus was on two large genera, Macaranga and Mallotus, and a number of smaller genera related to them. The phylogeny of these genera was studied using sequence data from plastid (trnL-F) and nuclear (ITS, ncpGS, phyC) markers. The results show that Macaranga is a monophyletic genus, but that Mallotus is paraphyletic for two reasons: 1) Mallotus sections Hancea and Oliganthae form a separate clade together with the genera Cordemoya and Deuteromallotus, and 2) the genera Coccoceras, Neotrewia, Octospermum and Trewia are part of the main Mallotus clade. To reflect these findings in the classifications, Neotrewia, Octospermum and Trewia were merged with Mallotus (the other necessary taxonomic rearrangements have been conducted separately). A taxonomic revision for these three genera was also conducted. Further, the phylogeny of the main Mallotus clade was studied in more details using both molecular (matK, gpd) and morphological data. Additionally, a taxonomic revision of the Malesian species in the genus Cleidion was conducted, and the morphology and phylogenetic position of previously insufficiently known African genus Afrotrewia was studied. Show less
