Mass Taxon-Sampling as a Strategy towards Illuminating the Natural History of Campanula (Campanuloideae)

Speciose clades usually harbor species with a broad spectrum of adaptive strategies and complex distribution patterns, and thus constitute ideal systems to disentangle biotic and abiotic causes underlying species diversification. The delimitation of such study systems to test evolutionary hypotheses is difficult because they often rely on artificial genus concepts as starting points. One of the most prominent examples is the bellflower genus Campanula with some 420 species, but up to 600 species when including all lineages to which Campanula is paraphyletic. We generated a large alignment of petD group II intron sequences to include more than 70% of described species as a reference. By comparison with partial data sets we could then assess the impact of selective taxon sampling strategies on phylogenetic reconstruction and subsequent evolutionary conclusions

Dry grasslands and thorn-cushion communities of Armenia: a first syntaxonomic classification

Aim: To provide the first syntaxonomic, plot-based classification of the dry grasslands and thorn-cushion communities in Armenia. Study area: Armenia. Methods: We sampled 111 vegetation plots (10 m2) and recorded environmental and structural parameters. We collected additional 487 relevés from surrounding countries for a broad-scale comparison. We used modified TWINSPAN to derive a syntaxonomic classification system, whose units were then compared among each other regarding species composition, structure, site conditions and distribution. Results: The classification of Armenian vegetation plots resulted in a 12-cluster solution. Unsupervised classification of the broad-scale dataset yielded five main groups, which were used for the high-level syntaxonomic assignments of the Armenian data. We assigned about half of the plots of the Armenian dataset to the Festuco-Brometea, while the remaining represented a potential new class, preliminarily called “Ziziphora tenuior-Stipa arabica grasslands”. Most of the syntaxa below class level are new to science, therefore we provide formal descriptions of three orders (Plantagini atratae-Bromopsietalia variegatae, Onobrychido transcaucasicae-Stipetalia pulcherrimae, Cousinio brachypterae-Stipetalia arabicae), four alliances (Acantholimono caryophyllacei-Stipion holosericeae, Artemision fragrantis, Onobrychido michauxii-Stipion capillatae, Onobrychido transcaucasicae-Stipion pulcherrimae) and six associations. We found significant differences in the topographic, climatic and soil characteristics, and structural parameters, species life forms and distribution range types between the grassland types at different syntaxonomic levels. The mean species richness was 47.3 (vascular plants: 46.8, bryophytes: 0.4, lichens: 0.1). Conclusions: We found remarkable differences of the Armenian dry grasslands from the previously known units and described most of the higher syntaxa and all the associations as new to science. Our study provides arguments for a potential new class of Ziziphora tenuior-Stipa arabica grasslands separate both from the Euro-Siberian Festuco-Brometea and the Anatolian Astragalo-Brometea. Finally, we found plot scale richness of vascular plants clearly above the Palaearctic average of dry grasslands and that of non-vascular plants clearly below, which calls for further biodiversity analyses. Taxonomic reference: Euro+Med (2023) for vascular plants, Hodgetts et al. (2020) for bryophytes, Nimis et al. (2018) for lichens except for Xanthoparmelia camtschadalis (Ach.) Hale. Abbreviations: EDGG = Eurasian Dry Grassland Group; DCA = detrended correspondence analysis; ICPN = International Code of Phytosociological Nomenclature (Theurillat et al. 2021); TWINSPAN = two-way indicator species analysis

Dry grasslands and thorn-cushion communities of Armenia: a first syntaxonomic classification

Aim: To provide the first syntaxonomic, plot-based classification of the dry grasslands and thorn-cushion communities in Armenia. Study area: Armenia. Methods: We sampled 111 vegetation plots (10 m2) and recorded environmental and structural parameters. We collected additional 487 relevés from surrounding countries for a broad-scale comparison. We used modified TWINSPAN to derive a syntaxonomic classification system, whose units were then compared among each other regarding species composition, structure, site conditions and distribution. Results: The classification of Armenian vegetation plots resulted in a 12-cluster solution. Unsupervised classification of the broad-scale dataset yielded five main groups, which were used for the high-level syntaxonomic assignments of the Armenian data. We assigned about half of the plots of the Armenian dataset to the Festuco-Brometea, while the remaining represented a potential new class, preliminarily called “Ziziphora tenuior-Stipa arabica grasslands”. Most of the syntaxa below class level are new to science, therefore we provide formal descriptions of three orders (Plantagini atratae-Bromopsietalia variegatae, Onobrychido transcaucasicae-Stipetalia pulcherrimae, Cousinio brachypterae-Stipetalia arabicae), four alliances (Acantholimono caryophyllacei-Stipion holosericeae, Artemision fragrantis, Onobrychido michauxii-Stipion capillatae, Onobrychido transcaucasicae-Stipion pulcherrimae) and six associations. We found significant differences in the topographic, climatic and soil characteristics, and structural parameters, species life forms and distribution range types between the grassland types at different syntaxonomic levels. The mean species richness was 47.3 (vascular plants: 46.8, bryophytes: 0.4, lichens: 0.1). Conclusions: We found remarkable differences of the Armenian dry grasslands from the previously known units and described most of the higher syntaxa and all the associations as new to science. Our study provides arguments for a potential new class of Ziziphora tenuior-Stipa arabica grasslands separate both from the Euro-Siberian Festuco-Brometea and the Anatolian Astragalo-Brometea. Finally, we found plot scale richness of vascular plants clearly above the Palaearctic average of dry grasslands and that of non-vascular plants clearly below, which calls for further biodiversity analyses. Taxonomic reference: Euro+Med (2023) for vascular plants, Hodgetts et al. (2020) for bryophytes, Nimis et al. (2018) for lichens except for Xanthoparmelia camtschadalis (Ach.) Hale. Abbreviations: EDGG = Eurasian Dry Grassland Group; DCA = detrended correspondence analysis; ICPN = International Code of Phytosociological Nomenclature (Theurillat et al. 2021); TWINSPAN = two-way indicator species analysis

Chronogram of <i>Campanula</i> and relatives (D680) inferred from the penalized-likelihood method implemented in r8s, and dated using one fossil constraint (yellow spiral).

<p>The yellow box refers to the time span between the stem and crown node of <i>Campanula</i> s.lat. Clades are represented by triangles proportional in size to the number of included accessions. Gray triangles indicate the respective outgroup and sister clades; blue triangles refer to “Cam” clades containing at least one accession of <i>Campanula</i> (Cam01 to Cam17; see text). White bars represent 95% confidence intervals (CI) for the respective node ages (blue: crow ages; white: stem ages). An asterisk indicates nodes for which CI could not be calculated. Ma = Mega Annuum or Million years; LOBE = Lobelioideae; CYPHI: Cyphioideae; CA-CYA: Campanuloideae-Cyanantheae; CA-WAH: Campanuloideae-Wahlenbergieae.</p

Maximum Parsimony Strict consensus tree of <i>Campanula</i> and relatives (D680).

<p>Part of the cladogram showing detailed relationships for clade Cam17. Values below branches indicate bootstrap support for the sustained clades. Pictures are representative specimens for clade 17 (clockwise from upper left: <i>Campanula latifolia</i>, <i>C. incurva</i>, <i>C. spicata</i>, and <i>C. barbata</i>). All photos from Guilhem Mansion.</p

Overview of the sampling strategy.

<p>The circular cladogram represents the Maximum Parsimony strict consensus tree inferred from the mass sampling (MS, D680). Dotted lines (red) indicate accessions sampled for the classification-guided sampling (CS, D088). Asterisks refer to accessions sampled for the phylogeny-guided sampling (PS, D101). Blue dots indicate crown groups for the respective "Cam" clades containing at least one accession of <i>Campanula</i> (Cam01 to Cam17; see text). LOBE = Lobelioideae; CYPHI: Cyphioideae; CA-CYA: Campanuloideae-Cyanantheae; CA-WAH: Campanuloideae-Wahlenbergieae.</p

Maximum Parsimony Strict consensus tree of <i>Campanula</i> and relatives (D680).

<p>Part of the cladogram showing detailed relationships for clades Cam13 to Cam16. Values below branches indicate bootstrap support for the sustained clades. Gray boxes indicate the respective outgroup and sister clades; blue boxes refer to “Cam” clades containing at least one accession of <i>Campanula</i> (Cam01 to Cam17; see text). A blue dot indicates the crown node of <i>Campanula</i> s.lat. Pictures are representative specimens for clades Cam13 (<i>Campanula asperuloides</i>), Cam14 (<i>Campanula draboides</i>), Cam15 (<i>Azorina vidalii</i>), and Cam16 (<i>Campanula macrostyla</i>). All photos from Guilhem Mansion, except Cam13 (Georgia Kamari & Dimitrios Phitos) and Cam16 (Galip Akaydin).</p

Maximum Parsimony Strict consensus tree of <i>Campanula</i> and relatives (D680).

<p>Part of the cladogram showing detailed relationships for outgroup and sister lineages, and clades Cam01, <i>Jasione</i>-<i>Feeria</i>, and Cam02 to Cam04. Values below branches indicate bootstrap support for the sustained clades. Gray boxes indicate the respective outgroup and sister clades; blue boxes refer to “Cam” clades containing at least one accession of <i>Campanula</i> (Cam01 to Cam17; see text). A blue dot indicates the crown node of <i>Campanula</i> s.lat. Pictures are representative specimens for clades Cam01 (<i>Campanula primuliifolia</i>), Cam02 (<i>Campanula exigua</i>), Cam03 (<i>Campanula persicifolia</i>), and Cam04 (<i>Legousia falcata</i>). All photos from Guilhem Mansion.</p