Showing papers in "Plant Ecology and Evolution in 2023"
TL;DR: In this paper , the authors developed a list of endemic vascular plants restricted to Italian forests, including 134 taxa, most of which are linked to closed-canopy forest habitats, while the others are also found in margins and gaps.
Abstract: Background and aims – Forests are among the most threatened ecosystems worldwide, and endemic plants are often a vulnerable component of the flora of a given territory. So far, however, understory forest endemics of southern Europe have received little attention and are poorly known for several aspects.
Material and methods – We developed the first list of native vascular plants that are restricted to Italian forests. Available information on taxonomy, regional distribution, ecology, biology, functional traits, and conservation status was collected for each taxon, allowing to identify major knowledge gaps and calculate baseline statistics.
Key results – The list includes 134 taxa, most of which are linked to closed-canopy forest habitats, while the others are also found in margins and gaps. The forest and non-forest Italian endemic flora differed in terms of taxonomic and life-form distribution. The rate and density of forest endemism increased with decreasing latitude and were highest in Sicily, Calabria, and Basilicata, where paleoendemic mono- or oligotypic genera also occur. Endemic phanerophytes were especially numerous on islands. Beech and deciduous oak forests were the most important habitats, but hygrophilous woodlands also host numerous endemics. Overall, the ecology, biology, and functional traits of the forest endemic taxa are still poorly known. The ratio diploids/polyploids was highest in the south and on the islands. Almost 24% of the taxa were assessed as “Critically Endangered”, “Endangered”, or “Vulnerable”, and 24% were categorized as “Data Deficient”, based on the IUCN system. Increasing frequency and intensity of fires was the most frequent threat.
Conclusions – This work can contribute to implement the European forest plant species list and serve as a basis for further research on a unique biological heritage of the continent. However, more knowledge about these globally rare taxa is needed, to support their conservation in changing forest landscapes.
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TL;DR: C Coutaportla lorenceana as mentioned in this paper , which belongs in the Portlandia complex, is comparable to that in the Chiococceae tribe, was proposed to include the latter complex based on molecular data, but the classification was controversial according to the morphology.
Abstract: Background and aims – Ongoing studies on Mexican Rubiaceae revealed an undescribed species of Coutaportla endemic to the Sierra Madre Occidental pine-oak forests in the state of Sinaloa, near the border with Durango, Mexico. The species is here described and illustrated, and its morphological characters are compared with those of the other species in the genus. Material and methods – This study is based on field observations, examination of herbarium specimens including digital images, and morphological studies based on samples from dried and spirit specimens. Key results – The morphological comparison of taxonomically important characters among the species of Coutaportla reveals conditions that were previously not reported for the genus. The placentation and ovule number of C. lorenceana , which belongs in the Portlandia complex, is comparable to that in the Chiococceae tribe. This tribe was proposed to include the latter complex based on molecular data, but the classification was controversial according to the morphology. Coutaportla lorenceana hence provides a morphological link between the Portlandia complex and the taxa traditionally placed in Chiococceae. The new species is assessed as Critically Endangered following the IUCN Red List criteria.
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TL;DR: In this article , two new species of Renealmia are described from Rwanda and Burundi in connection with the preparation of the family treatment for the Flore d'Afrique centrale.
Abstract: Background and aims – The Zingiberaceae of Rwanda are revised, and three new records of Aframomum species (A. corrorima, A. daniellii, A. zambesiacum) are provided. One previously recorded species, A. alboviolaceum, has to be excluded from the Flora of Rwanda. Two new species of Renealmia are described from Rwanda and Burundi in connection with the preparation of the family treatment for the Flore d’Afrique centrale.
Material and methods – Field work and standard herbarium practices were applied.
Key results – Renealmia timmiorum sp. nov. is similar to R. cincinnata and R. cabrae, and R. susannae-katziae sp. nov. is similar to R. africana and R. dewevrei. The differences with these species are discussed and distribution maps for the new taxa are presented. Renealmia timmiorum is assessed as Least Concern (LC), while R. susannae-katziae is assessed as Endangered (EN).
TL;DR: The first large-scale inventory of the Podostemaceae family in Gabon was presented in this paper , with 500 newly collected specimens representing 91.4% of all known collections of this family from Gabon.
Abstract: Background and aims – Podostemaceae is a family of strictly aquatic plants found in rapids and waterfalls. Despite a recent treatment in the Flore du Gabon, the family remained poorly known, with no major studies including Gabonese collections, and almost no targeted inventories since 1966. We present the first large-scale inventory of this family in Gabon, targeting Podostemaceae throughout the country, providing new additions to the flora of Gabon and many new records of poorly known species.
Material and methods – Fieldwork was conducted in Gabon between 2017 and 2021. The collected specimens were primarily preserved in ethanol with associated silica gel-preserved material and photographs. Material available at BR, BRLU, LBV, MO, P, WAG, and Z/ZT was examined. For each species, information on distribution and ecology is presented, as well as a distribution map in Gabon.
Key results – The 500 newly collected specimens represent 91.4% of all known collections of Podostemaceae from Gabon. Three taxa are newly recorded for the country, including one genus (Inversodicraea tenax, Ledermanniella schlechteri, and Saxicolella nana). New distribution records are also presented for 13 little-known species. Four taxa are excluded from the Gabonese flora (the genus Dicraeanthus, Inversodicraea ledermannii, Ledermanniella sanagaensis, and Macropodiella garrettii). To date, 20 species belonging to five different genera are known to occur in Gabon. A new combination is proposed for Ledermanniella nicolasii, and Inversodicraea tanzaniensis is now considered as a synonym of Inversodicraea tenax.
TL;DR: In this article , the authors identified two likely micro-endemic new species of Hippeastrum from the Atlantic Forest, which are considered critically endangered due to their single known location and small population size.
Abstract: Background and aims – The Atlantic Forest is among the five most important biodiversity hotspots in the world, harbouring one of the highest levels of endemism and species richness in the tropics. The region has been suggested as a centre of diversity for the genus Hippeastrum, which comprises about one hundred species distributed throughout the Neotropics. Due to its large and showy flowers, the genus is highly sought after by collectors and horticulturists around the world, with hundreds of hybrids produced and traded for centuries. However, most of its species are still known from only one or a few populations, and several are officially recognized as endangered. Monographic studies on the genus Hippeastrum in Brazil have revealed two likely microendemic new species from the Atlantic Forest.
Material and methods – The morphological descriptions of the new species are based on herbarium specimens and cultivated plants, as well as in situ observations. Descriptions and measures were taken following standard procedures. Preliminary conservation assessments followed IUCN guidelines and criteria.
Key results – Both species show typical morphology of the subgenus Hippeastrum, in which they should be placed. They can be distinguished from similar taxa, including some of the most widely distributed and known species of the genus, by several floral characters. Data on ecology, conservation, and photographs and illustrations are provided, as well as comparisons with related species. An identification key to the Brazilian Atlantic Forest species of Hippeastrum is provided, accompanied by photographs of these species in their natural habitats.
Conclusion – The new species are considered critically endangered due to their single known location and small population size. The findings reinforce the need for continued sampling across different regions of the Atlantic Forest, as well as the importance of systematic studies conducted by specialist taxonomists.
TL;DR: Stigmatodon lemeanus is classified as Vulnerable according to the IUCN Red List criteria as discussed by the authors , which is a monophyletic genus currently comprising 33 species, all endemic to rocky outcrops, mainly inselbergs, from the Atlantic Forest and campos rupestres of the Espinhaço range, Brazil.
Abstract: Background and aims – Stigmatodon (Bromeliaceae) is a monophyletic genus currently comprising 33 species, all endemic to rocky outcrops, mainly inselbergs, from the Atlantic Forest and campos rupestres of the Espinhaço range, Brazil.
Material and methods – Our fieldwork in the inselbergs of the Atlantic Forest of the state of Espírito Santo led to the discovery of a new Stigmatodon species with a tubo-laciniate stigma type. Standard herbarium taxonomy practices were adopted to study the novelty. Morphological data were obtained from herbarium specimens and fresh material collected in the field.
Key results – Stigmatodon lemeanus is here described and illustrated. Diagnostic characters and affinities of the new species are discussed, accompanied by notes on its ecology, geographic distribution, and conservation status. A key to the species of Stigmatodon from Espírito Santo state is provided. The novelty is similar to S. goniorachis from coastal inselbergs of Rio de Janeiro and S. attenuatoides, another inselberg endemic from southern Espírito Santo. Stigmatodon lemeanus is preliminarily assessed as Vulnerable (VU) according to the IUCN Red List criteria. Additionally, we present a new combination of Tillandsia oligantha in Stigmatodon, correcting a nomenclatural error.
TL;DR: In this paper , the authors proposed and tested two hypotheses: 1) the fitness impacts of two species of herbivores that affect the same resource (i.e. feed on the same tissue in a similar fashion) will combine in a synergistic pattern (if that resource is not limiting reproduction when plants do not experience herbivory).
Abstract: Background and aims – The manner by which the effects of multiple antagonists combine is a fundamental issue in ecology. This issue has been especially important in plant-herbivore evolutionary ecology—particularly predicting whether the combined fitness impacts of multiple herbivores on a shared host plant can be inferred by simply adding the individual impacts that each herbivore has when feeding alone. Despite accumulating empirical data, relatively little theoretical progress has been made in explaining why impacts of herbivore damage often combine nonadditively, as well as predicting the conditions that lead to a greater-than-additive (synergistic) or to a less-than-additive (subadditive) pattern.
Material and methods – Based on considerations of limiting resources and source-sink relationships, I proposed and tested two hypotheses: 1) The fitness impacts of two species of herbivores that affect the same resource (i.e. feed on the same tissue in a similar fashion) will combine in a synergistic pattern (if that resource is not limiting reproduction when plants do not experience herbivory), and 2) The fitness impacts of two herbivores that affect different resources (i.e. feed on different tissues) will combine in a subadditive pattern. I performed a field experiment in which horsenettle (Solanum carolinense) was exposed to a factorial combination of four levels of leaf herbivory and five levels of simulated floral herbivory.
Key results – The results were consistent with both hypotheses: 1) The combined fitness impact of flower damage that was simulated as being caused by two florivorous species feeding on the same plants was greater than the sum of the same total amount of damage when the two species were simulated as feeding individually; and 2) The combined fitness impact of the leaf and floral damage was less than the sum of the same total amount of damage when the two species fed individually.
Conclusions – The main ecoevolutionary implication of these results is that subadditive impacts of leaf- and flower-feeding herbivores could weaken selection for resistance in horsenettle (or any plant species that hosts multiple herbivores), and thus subadditive impacts may contribute to the maintenance of diverse herbivore communities sharing a species of host plant.
TL;DR: A taxonomic revision for the Ochna holstii complex using a multi-evidence approach is presented in this paper , which combines genomic-scale data of multiple accessions per species with morphological data.
Abstract: Background and aims – Ochna holstii and its allies represent an ecologically important group in a variety of lowland to montane habitats in tropical eastern and southern Africa. Identifying and delimiting species within this group has proved challenging due to a lack of variation in morphological characters. We combine genomic-scale data of multiple accessions per species with morphological data to generate a taxonomic revision for the Ochna holstii complex using a multi-evidence approach.
Material and methods – A total of 50 samples representing eight species were analysed using target enrichment and a custom bait kit. Phylogenetic analysis was conducted using the multi-species coalescent model and a concatenation maximum likelihood method, and gene tree discordance was investigated. Herbarium specimens of the O. holstii complex were studied in detail for informative morphological characters, supplemented where possible from field collections, and a full taxonomic revision is provided.
Key results – Within Ochna sect. Schizanthera Clade I, our study confirms that all species are monophyletic and supported by morphological data with the exception of O. holstii, which is paraphyletic. A new species, O. mchanga, previously confused with O. polyneura, is described, and the placement of another recently described species, O. maguirei, is confirmed for the first time using molecular data.
Conclusion – The widespread montane tree Ochna holstii is non-monophyletic in its current circumscription and likely gave rise to the more range-restricted O. oxyphylla and O. stolzii. We suggest that an integrated taxonomy approach, using both molecular and morphological data, is essential for deciphering difficult species relationships in Ochna.
TL;DR: In this article , a new tree species in the genus Drypetes (Putranjivaceae) distributed in Cameroon and eastern Nigeria, D. stevartii, was associated with D. verrucosa, another tree species endemic to Gabon, due to its warty fruits and to the overall morphological similarities of both species.
Abstract: Background and aims – Specimens of a new tree species in the genus Drypetes (Putranjivaceae) distributed in Cameroon and eastern Nigeria, D. stevartii, were associated with D. verrucosa, another tree species endemic to Gabon, due to its warty fruits and to the overall morphological resemblances of both species.
Material and methods – The present study is based on the study of 20 gatherings of D. verrucosa and 26 gatherings of D. stevartii. Morphological observations on herbarium specimens belonging to the new species and D. verrucosa were carried out in order to describe them.
Key results – This treatment includes the detailed descriptions of these two species, the typification of their names, a comparative table summarizing their main morphological differences, an identification key, photographs of both, as well as information about their distribution, habitat, and phenology. Preliminary IUCN Red List assessments show that both D. verrucosa and D. stevartii are ‘Near Threatened’ species.
TL;DR: In this article , two populations of Asphodelus fistulosus in the Chihuahuan Desert were monitored for reproductive phenology and their behavior were described, and assessed the breeding system through floral morphological characters and the mating system in controlled pollination experiments.
Abstract: Background and aims – Understanding the traits that lead to the invasion potential of invasive alien species (IAS) provides insight for their management. The reproductive traits of IAS help us understand the mechanisms that allow for their invasive potential, and colonization into new ranges. Asphodelus fistulosus is a native Mediterranean species commonly found invading Australia, South-East Asia, South Africa, and North America.
Materials and methods – Two populations of A. fistulosus in the Chihuahuan Desert were monitored for reproductive phenology. Floral visitors and their behaviour were described, and we assessed the breeding system through floral morphological characters and the mating system in controlled pollination experiments.
Key results – Reproductive phenology showed continuous reproduction throughout the year. Floral morphology suggested a facultative autogamous breeding system, but the mating system was mixed with autonomous selfing. Flowers lasted one day, with anthesis lasting 11 h. Floral visitors of A. fistulosus consisted of a variety of taxa including species of Coleoptera, Hymenoptera, and Lepidoptera, the exotic Apis mellifera being the most frequent visitor.
Conclusions – The reproductive traits of A. fistulosus in the invaded range provide the biological potential for further invasion. The continuous production of reproductive structures attracts many diverse pollinators, and the autonomous self-pollination implies that a single plant has the potential to develop a new population, which makes the control of this IAS a global challenge.
TL;DR: In this article , the authors re-assess this hypothesis, discuss the issues that have led to this assumption, and offer insights on the importance of carefully using herbarium collections and incorporating morphological evidence in systematic studies.
Abstract: Background and aims – Keraunea is a Brazilian endemic genus that has sat uncomfortably in Convolvulaceae where it was placed due to an enlarged and adnate fruit bract typical of Neuropeltis. A recent molecular phylogeny suggested that two of its five morphologically almost identical species actually belong to two different families, Malpighiaceae (superrosids) and Ehretiaceae (superasterids). Later studies have demonstrated that Keraunea effectively belongs to Ehretiaceae, but the proposal of one species belonging to Malpighiaceae has remained problematic. In this study, we re-assess this hypothesis, discuss the issues that have led to this assumption, and offer insights on the importance of carefully using herbarium collections and incorporating morphological evidence in systematic studies.
Material and methods – Sequences of matK, rbcL, and ITS for all 77 currently accepted genera of Malpighiaceae, K. brasiliensis and Elatinaceae (outgroup) were compiled from GenBank and analysed with Maximum Likelihood and Bayesian Inference criteria for nuclear, plastid and combined datasets. Additional database and herbarium studies were performed to locate and analyse all duplicates of the holotype of K. brasiliensis to check for misidentified or contaminated material.
Key results – Our examination of expanded DNA datasets and herbarium sheets of all K. brasiliensis isotypes revealed that a mistake in tissue sampling was, in fact, what led to this species being proposed to belong in Malpighiaceae. Kew’s isotype had a leaf of Malpighiaceae (likely Mascagnia cordifolia) stored in the fragment capsule, which was sampled and sequenced instead of the actual leaves of K. brasiliensis. Recently published studies have settled the placement of Keraunea in Ehretiaceae (Boraginales) and proposed three additional species.
Conclusions – DNA sequences can be helpful in classifying taxa when morphology is conflicting or of a doubtful interpretation, with molecular phylogenetic placement being established as a popular tool accelerating the discovery of systematic relationships. Nonetheless, molecular techniques are also susceptible to methodological mistakes, which necessitates building a solid foundation of plant morphology and taxonomy to avoid artefacts in phylogenetic studies.
TL;DR: A short taxonomic revision of the genus Cephalanthus, taking into consideration morphological aspects previously underestimated or not considered, and to describe a new monospecific genus based on comparative morphological analysis is presented in this article .
Abstract: Background and aims – The genus Cephalanthus belongs to the tribe Naucleeae together with 26 other genera. Members of Cephalanthus mainly grow in temperate and subtropical wetlands in the Americas and Asia, but there is a single African species that is associated with forest margins and rocky outcrops in moist temperate grasslands. The genus comprises six species and was historically known to have species with a markedly disjunct distribution: three species are from the Americas: C. glabratus , C. occidentalis , and C. salicifolius ; two species are from tropical Asia: C. angustifolius and C. tetrandrus , and one species is from tropical Africa: C. natalensis . Recent molecular phylogenetic studies have supported the monophyly of the genus, however, most of the morphological synapomorphies are absent in the only African species, which is sister to the remaining species of the genus. This work aims to provide a short taxonomic revision of the genus Cephalanthus , taking into consideration morphological aspects previously underestimated or not considered, and to describe a new monospecific genus based on comparative morphological analysis. Material and methods – Vegetative and reproductive material from all the species of Cephalanthus were analysed following conventional taxonomy techniques. Key results – We transferred C. natalensis to a new genus, Sylvainia . Morphological similarities and differences between Cephalanthus and the new genus are discussed. Cephalanthus glabrifolius , a poorly known species and previously considered a synonym of C. tetrandrus , is resurrected as a valid species, bringing the number of species in Cephalanthus to six again. All species are described, illustrated, and their known distributions plotted on regional maps. Conclusion – The subtribe Cephalanthinae now has two genera, its type Cephalanthus with six species, and a new monospecific genus Sylvainia endemic to south-eastern Africa. Based on the amended description of Cephalanthus , now absent from Africa, the generic concept is substantially modified, being represented now by three American and three Asian species.
TL;DR: In this article , morphometric analyses are used to test species limits to establish more stable morphological delimitations of the Cyperus margaritaceus-niveus complex, a group of ten tropical species from sub-Saharan Africa and Madagascar.
Abstract: Background and aims – The Cyperus margaritaceus-niveus complex is a group of ten tropical species from sub-Saharan Africa and Madagascar: C. karlschumannii, C. kibweanus, C. ledermannii, C. margaritaceus, C. niveus, C. nduru, C. obtusiflorus, C. somaliensis, C. sphaerocephalus, and C. tisserantii. They are characterised by a capitate head of white-yellow spikelets and modified culm bases and recent molecular analysis puts them in a distinct clade. The group lacks a modern taxonomic revision, and the taxa described in the Flora treatments of the past 50 years differ considerably in their circumscription. In this study, morphometric analyses are used to test species limits to establish more stable morphological delimitations of the taxa.
Material and methods – An examination of 15 morphological characters on 489 herbarium specimens was carried out and the data was analysed using Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) with cross-validation, and Classification and Regression Tree (CART) analysis. Cyperus kibweanus was not further considered due to lack of material.
Key results – Both PCA and LDA showed varying degrees of overlap in the nine remaining taxa, with no single group clearly separating in multivariate space. However, cross-validation clearly showed C. margaritaceus as a distinct entity despite its overwhelming presence in the PCA. Both LDA and CART failed to separate C. niveus as a distinct group as its specimens were dispersed among the other groups. Differing results were obtained for other taxa depending on the type of analysis. Cyperus margaritaceus, C. nduru, and C. sphaerocephalus were divided into two groups by CART but re-examination of the specimens does not definitively support the idea that these infraspecific groups represent separate taxa.
Conclusions – The results show that eight morphospecies are recognised by LDA and six morphospecies by CART. Characters used to separate the taxa in Flora treatments scored high loadings in the analysis showing their high taxonomic utility value. The methods used can be applied to resolving other complexes in the Cyperaceae.
TL;DR: In this paper , a new bluish-leaved palm species, Syagrus carvalhoi, was discovered in the Serra do Cabral massif in Minas Gerais State, Brazil.
Abstract: Background and aims – This study is part of ongoing research on the Arecaceae Flora of the Serra do Cabral, an isolated massif in the southwest of the Espinhaço Range in Minas Gerais State. Because of the isolation of the massif, the area has a rich biodiversity and a high level of endemism. While searching for populations of the rare and critically endangered Syagrus cabraliensis, a new bluish-leaved palm species was discovered and it is described here.
Material and methods – The new species’ morphology is described based on field collections. The pinnae were analysed using SEM and LM cross- and longitudinal sections following default methodology. In addition, we compared the species to S. cabraliensis and provided ecological notes and a conservation status assessment.
Key results – Syagrus carvalhoi resembles S. cabraliensis but they can easily be distinguished by morphoanatomical characters. Both species occur non-sympatrically in the Serra do Cabral, in contrasting microhabitats: S. carvalhoi in the southern quartzitic campos rupestres and S. cabraliensis in the northern ferruginous campos rupestres. A key to the known grass-like Syagrus species from the massif is provided. Based on the restricted area of occurrence and the anthropogenic threats, Syagrus carvalhoi is assessed as critically endangered.
Conclusion – Syagrus carvalhoi is the second grass-like endemic Syagrus species from the Serra do Cabral and presents rare characters within the genus (grass-like aspect, colonial habit, flowers in tetrads, and the stem forking at or below the ground). This discovery corroborates that this isolated OCBIL is a home for endemic and rare palm species. The Serra do Cabral massif has proved a source of morphological and anatomical novelties in Arecaceae, affecting the taxonomy and understanding of the evolution and ecology of palms. Our results reinforce the notion that it is important to conserve this area with rich and rare biodiversity but under alarming and unprecedented threats.
TL;DR: In this paper , the authors investigated the effect of masting ectomycorrhizal legumes in a lowland rainforest in Cameroon for Tetraberlinia korupensis, whose crowns were attacked by an outbreaking black caterpillar.
Abstract: Background and aims – Where one or several tree species come to dominate patches of tropical forest, as many masting ectomycorrhizal legumes do in Central Africa, ecological theory predicts they may be prone to herbivory, which might alter their reproductive output. This was indirectly investigated in lowland rainforest in Cameroon for Tetraberlinia korupensis , whose crowns were attacked in 2008 by an outbreaking black caterpillar—identified as an Achaea sp., probably A. catocaloides —in Korup National Park. Material and methods – Field-collected data on tree-level seed and fruit (pod) production of T. korupensis in its 2008 masting event were compared with that of its two co-dominant neighbours ( T. bifoliolata , Microberlinia bisulcata ), whose populations masted in 2007 (and 2010). To do this, bivariate regression models (linear, polynomial, ZiG [zero-inflated gamma model]), contingency table analysis, and non-parametric measures of dispersion were used. Key results – Assuming T. korupensis is prone to Achaea caterpillar attacks, empirical data support the hypothesized lower proportion of adults participating in its masting (54% in 2008) than for either masting population of M. bisulcata (98% in 2007, 89% in 2010) or T. bifoliolata (96% in 2007, 78% in 2010). These fruiting T. korupensis trees were about one-third larger in stem diameter than conspecific non-fruiters and produced as many pods and seeds per capita as T. bifoliolata . However, regressions only modestly support the hypothesis that the positive tree size–fecundity relationship for T. korupensis was weaker (i.e. lower adj. R 2 ) than for M. bisulcata (whose leaves are morphologically similar) or T. bifoliolata , with mostly similar dispersion about the median among these species. Conclusion – Altogether, the findings suggest a role for tolerance in nutrient-poor forests. It is postulated that instead of conferring resistance to herbivores, the ectomycorrhizas associated with these trees may enable them to more quickly recover from potential yet unpredictable insect outbreaks.