DOI: 10.5091/plecevo.187671

Authors: Amadeu Manoel dos Santos-Neto, Jean Carlos Santos

Abstract: Background and aims – Flowering phenology is a key niche axis structuring plant communities by influencing reproductive success, plant-pollinator interactions, and species coexistence. However, how flowering timing interacts with pollinator niches and evolutionary constraints remains poorly understood in stressful Neotropical ecosystems such as Restingas. We investigated whether flowering phenology and pollinator niches are evolutionarily coupled or decoupled in a coastal herbaceous community. Material and methods – We monitored flowering phenology weekly for one year in a Restinga herbaceous community in Sergipe, northeastern Brazil, comprising 15 species from 10 families. We quantified temporal flowering patterns, tested climatic drivers of flowering richness, characterized plant-pollinator interaction networks, and evaluated phylogenetic signal in flowering phenology and pollinator niches using comparative methods. Key results – Flowering occurred continuously throughout the year but showed non-random temporal synchrony at the community level, with a flowering peak during the dry season. Flowering richness was best explained by lagged temperature four months prior and photoperiod, indicating delayed climatic control. Species with yellow flowers exhibited significantly aggregated flowering times. The plant-pollinator network was highly specialized and nested, dominated by a few generalist pollinators, including Xylocopa cearensis, Synoeca cyanea, and Eurema elathea. Flowering phenology exhibited strong phylogenetic signal, with closely related species flowering at similar times, whereas pollinator niches showed no phylogenetic structure and were not predicted by temporal flowering overlap. Importantly, neither floral traits nor temporal overlap in flowering explained variation in pollinator assemblage composition, indicating a decoupling between flowering phenology and realized pollinator niches. Conclusion – Our results reveal a decoupling between evolutionarily conserved flowering phenology and ecologically flexible pollinator interactions. This decoupling promotes species coexistence in Neotropical Restinga herbaceous communities by ensuring temporal continuity of floral resources while allowing niche partitioning through variable biotic interactions.

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DOI: 10.5091/plecevo.138752

Authors: Marco O.O. Pellegrini, David R. Hunt, Jason R. Grant, Avery Rowe, Higor Antonio-Domingues, Rafael F. de Almeida

Abstract: Background and aims – Tradescantia subg. Campelia is the most morphologically diverse and one of the most taxonomically complex subgenera of Tradescantia. This makes taxonomic efforts within this group challenging, especially due to the current lack of formal recognition of monophyletic infrageneric groups and their widespread horticultural use. Thus, continuing our previous efforts, we provide a sectional classification for the subgenus, combined with a taxonomic revision of T. sect. Rhoeo. Material and methods – This study was based on a combination of systematic, micro- and macromorphological, palynological, and horticultural data. We analysed type specimens, protologues, field images, and herbarium sheets of all names, in addition to growing all species and cultivars. We have also reviewed previously published palynological data for the recognised species and provided all needed corrections and updates, in addition to a novel interpretation of their taxonomic relevance. Key results – We propose the subdivision of T. subg. Campelia into four sections: 1) T. sect. Campelia; 2) T. sect. Corinna; 3) T. sect. Cymbispatha; and 4) T. sect. Rhoeo. These sections are supported by a combination of molecular, micro- and macromorphological, anatomical, palynological, cytological, and phytochemical data. Within T. sect. Rhoeo, we accept two species, T. spathacea and the newly recognised T. concolor. Horticulturally, we propose the T. spathacea Bantam Group, including five dwarf cultivars, while T. spathacea ‘Vittata’ is the only regular-sized variegated cultivar of wild origin. We also explore the palynology of T. sect. Rhoeo, highlighting palynotaxonomically relevant characters in Tradescantia and T. subg. Campelia. Conclusions – We lay the groundwork for ongoing and future studies on T. subg. Campelia. The recognition of sections within this subgenus will facilitate identification, communication, and enable the recognition of functional taxonomic groups for future systematic and taxonomic studies. The combination of palynology and horticulture provides further support for the taxonomy and systematics of Tradescantia, and should be consistently included in future studies of the group.

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DOI: 10.5091/plecevo.160401

Authors: Getsemani López-Gea, Mónica Ilsy Jiménez Rojas, Alexander Vrijdaghs, Andrés Xingú-López, Rolando Cifuentes-Velásquez, Ivonne Sánchez-del Pino

Abstract: Background and aims – Amaranthus cruentus, native to Mexico and Guatemala, has significant cultural, medicinal, and ornamental uses and growing agricultural relevance. However, little research has focused on its origin and domestication. To determine its domestication syndrome, we identified a set of domestication-linked traits in cultivated A. cruentus and compared them with its wild ancestor A. hybridus and with A. cruentus accessions from different regions. We assessed whether the domestication syndrome enables us (1) to differentiate between the wild and cultivated species and (2) to determine the level of domestication in populations of A. cruentus from different putative centres of domestication. Material and methods – Populations of A. cruentus and A. hybridus were sampled from Mexico and Guatemala. Ten morphological traits related to vegetative stage, anthesis, and seed maturation were evaluated to identify patterns linked to domestication. PERMANOVA was used to analyse differences in traits between cultivated and wild populations. Key results – Basal stem size, plant height, inflorescence length, and seed yield (total mass) differed significantly between A. cruentus and A. hybridus. Amaranthus cruentus had a broader range of seed and inflorescence colours. The Mexican accessions had taller plants, longer inflorescences, and greater seed yield than the Guatemalan. Conclusion – The selected set of characters unambiguously distinguishes the wild A. hybridus from the cultivated A. cruentus, enables differentiation of domestication levels, suggesting that Mexican accessions are more domesticated than the Guatemalan.

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DOI: 10.5091/plecevo.164557

Authors: Cynthia Hong-Wa, Guillaume Besnard

Abstract: Background and aims – Madagascar’s rich flora originated mostly from in situ diversification, and the large-scale plant species richness pattern is mainly explained by spatial heterogeneity. However, mechanisms underlying plant community assembly remain largely unexplored. We aimed to understand the coexistence of a species swarm in the Malagasy olive (Noronhia, Oleaceae) on the northern massif of Montagne d’Ambre and to gain insights into the factors influencing community assembly. Material and methods – We used 13 environmental and 17 trait variables sampled across 24 plots and 13 species on the mountain, respectively. We determined likely trait-environment relationships across space using the multivariate RLQ analysis, the bivariate fourth-corner method, and their combination. We also checked for phylogenetic signal (Blomberg’s K and Moran’s I) among traits and assessed the phylogenetic community structure (SES.MPD and SES.MNTD) using nested spatial and phylogenetic scales. Key results – Significant trait-environment relationships were recovered with the multivariate and the combined multi–bivariate analyses at a large spatial scale, whereas patterns at small spatial scales were unclear. Distinct assemblages at lower and higher elevations were identified and appeared to be influenced by bioclimate and soil gradients. Strong phylogenetic signals were detected in seven traits across spatial scales, regardless of phylogenetic scales. The communities exhibited an overall pattern of phylogenetic clustering with a large phylogenetic scale, while a hint of overdispersion emerged in the low-elevation assemblage with a small phylogenetic scale. Conclusion – Multiple mechanisms may influence the coexistence of the Noronhia swarm on Montagne d’Ambre, with environmental filtering and niche partitioning seemingly acting on vegetative and reproductive functions, respectively. More focus on reproductive biology will provide further insights into the assembly of Malagasy plant communities. This study also highlights the conservation values of Montagne d’Ambre as a unique ecosystem supporting the flora, fauna, and human populations of the northernmost region of Madagascar.

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DOI: 10.5091/plecevo.160271

Authors: Angélica Aparecida Ávila, Cássio Cardoso Pereira, Crislaine Paula de Oliveira, Carlos A. Ordóñez-Parra, Sérgio Gualberto Martins, Gislene Carvalho de Castro

Abstract: Background and aims – Hedgerows may play a crucial ecological role in maintaining connectivity in fragmented Atlantic Forest landscapes. However, little is known about their contribution to ecological processes, particularly seed rain. Material and methods – To test this, we conducted a study in Ritápolis, Minas Gerais, Brazil, comparing a 500-meter-long hedgerow corridor with a 10.5-hectare forest fragment. We installed 20 seed collectors in each area and monitored them for a year, testing the hypothesis that hedgerow corridors have equivalent levels of litter, fruit, and seed production compared to preserved forest fragments. Key results – The results revealed that hedgerows can present greater fruit richness and higher litter dry weight than adjacent forest fragments. Furthermore, the other parameters evaluated in these hedgerows were equivalent to those observed in fragmented areas, reinforcing their importance in biodiversity conservation in rural landscapes. These findings directly support the hypothesis tested, highlighting hedgerows as essential structures for maintaining ecological processes, increasing environmental connectivity, and mitigating the impacts of forest fragmentation. Conclusion – This study contributes to the understanding of the role of ecological connectivity in hedgerows, paving the way for further research that can expand this knowledge.

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DOI: 10.5091/plecevo.161947

Authors: D. Jithmi M. De Silva, B.D. Punsara Dharaka, K.M.G. Gehan Jayasuriya, Filip Vandelook

Abstract: Background and aims – Climate change is a significant global challenge affecting soil health and agriculture, including increased soil salinity levels. Certain salt-tolerant wild species can be considered for crop improvement and provide a solution to increasing salinization. We studied the inter-population variation in salt tolerance of Vigna marina seedlings, to explore the potential use of these wild resources to improve cultivated Vigna and for better conservation decisions. Material and methods – Inter-populational variation in salinity tolerance of seedlings of four different V. marina populations growing in different regions in Sri Lanka (Unawatuna, Mahamodara, Negombo, and Thalpe) was studied. Seedlings from seeds collected from these populations were grown under 0, 100, 1000, 2000, 10,000, and 20,000 ppm NaCl concentrations, following standard salinity tolerance test procedures. The plant performance was evaluated by measuring biomass, root: shoot ratio, height, growth rate, and chloride ion accumulation in leaves, stems, and roots. Finally, the performance of the V. marina populations was compared with two commercial varieties of Vigna radiata (MI6 and Ari), one of which was considered salt-tolerant. Key results – All seedlings showed reduced growth at 10,000 and 20,000 ppm NaCl concentrations. The Negombo population showed the highest total dry mass at 20,000 ppm, and seedlings from all populations survived at 20,000 ppm salt concentration, except those from the Mahamodara population. Overall, the Thalpe population performed best at 20,000 ppm. The highest salt accumulation was recorded in leaves and stems rather than in roots. Commercial V. radiata varieties did not survive the highest salt concentrations (10,000 and 20,000 ppm). Conclusion – Given that V. marina populations collected in different locations show considerable inter-populational variation in salinity tolerance, we recommend conserving multiple V. marina populations to cover the range in variability in salinity tolerance traits. Natural populations of V. marina exhibited better survival at high salinity levels as compared to the commercial salt-tolerant V. radiata varieties, highlighting the halophytic nature of V. marina, and its putative importance in developing Vigna varieties that can be cultivated in more saline conditions.

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DOI: 10.5091/plecevo.139573

Authors: Lovanomenjanahary Marline, Claudine Ah-Peng, Olivier Flores, Terry Hedderson

Abstract: Background and aims – Epiphytic bryophytes play a crucial role in forest ecosystems by contributing to water retention, nutrient cycling, and microhabitat creation. However, despite their ecological importance, epiphytic bryophytes in Madagascar remain poorly studied, especially in terms of their functional traits and responses to environmental change. This study addresses this gap by investigating epiphytic liverwort communities along an elevational gradient in northern Madagascar. We aim to assess the relationship between functional diversity among liverwort species and community assembly using a trait-based approach, focusing on how habitat filtering and niche differentiation shape community structure. Material and methods – Epiphytic bryophytes were collected at 10 elevations along an elevational transect from 250 to 2050 m. We measured 12 morphological traits related to resource use, life history, defense, desiccation resistance, and photosynthetic activity. Functional evenness (FEve) and functional dispersion (FDis) were calculated for each community. To investigate functional responses underlying community assembly, we measured community-weighted means (CWM) and variances (CWV) for each trait along the transect. We analyzed trait-environment relationships using multiple general linear models and evaluated community assembly processes (convergence or divergence) across the gradient. Key results – Community assembly is influenced by environmental conditions and vegetation structure. At lower elevations, higher temperatures and taller vegetation lead to trait convergence, particularly in size-related traits. In contrast, at higher elevations, increased species richness is associated with trait divergence. Habitat filtering drives trait convergence at lower elevations, while niche differentiation becomes more important at species-rich higher elevations. Conclusion – Morphological traits reveal how habitat filtering and niche differentiation jointly influence species distribution. Including physiological traits like water-holding capacity and carbon fixation in future studies will provide deeper insights into ecosystem processes. Together, these findings will contribute to a better understanding of the mechanisms that shape biodiversity in tropical forest ecosystems.

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DOI: 10.5091/plecevo.124295

Authors: Petra Wester, Patricia Brühn

Abstract: Background and aims – Fluorescence is the emission of light by a fluorophore that has absorbed light of shorter wavelengths. While the role of fluorescence in visual communication has been documented in some animals (budgerigars, gelatinous zooplankton), it is controversially discussed in plants. Floral nectar fluorescence has been mainly found in flowers pollinated by bees. It has been suggested as direct visual cue by which bees can evaluate the available quantity of nectar, thus being important for pollination and foraging efficiency. However, this function has been questioned, since fluorescence is said to be obscured by floral reflections due to low quantum efficiency. The aim of this study was to examine the nectar of plants pollinated by non-flying mammals, namely Eucomis regia, Massonia grandiflora, M. echinata, and M. pustulata (Asparagaceae) from South Africa. Material and methods – To detect possible fluorescence in flowers, the plants were illuminated in a darkened room under UV light and photographed with a camera equipped with a UV/IR cut filter (transmitting at 400–700 nm). Key results – Within the inflorescences, the nectar of all species showed blue to bluish fluorescence and UV absorption. Separated nectar also fluoresced. Conclusion – As fluorescence in flowers occurs not only in bee-pollinated plants but also in plants pollinated by wind, and by nocturnal or crepuscular pollinators (non-flying mammals, bats, moths) for which floral scent is an important attractant, floral fluorescence seems to have no adaptive value for the attraction of flower visitors. We discuss the potential role of fluorescence in flowers as just a by-product of compounds that might have other functions such as visual attraction by reflection (or UV absorbance), protection of genetic material in pollen from UV induced damage, or as a floral filter causing nectar to be bitter, repelling ineffective pollinators but not effective ones.

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DOI: 10.5091/plecevo.120167

Authors: Mike Opgenorth, Emily Sailing, Nina Rønsted, Dustin Wolkis

Abstract: Background and aims – Gardenia species are ecologically, culturally, and economically significant but the three native species of Gardenia in Hawai‘i are assessed as Critically Endangered. Seed banking is the most cost effective and efficient means of conserving plant material ex situ. To better understand the conservation physiology of Hawaiian and South Pacific Gardenia spp. and support their conservation, we asked 1) How do seeds respond to different temperatures and light and dark regimes? 2) What class of dormancy, if any, do seeds exhibit? 3) How does seed germinability respond over time in a seed bank? and 4) What is the conservation status and level of ex situ representation of Gardenia globally? Material and methods – To answer these questions, we used 19 accessions of fresh seeds and seeds stored for varying periods of time in the National Tropical Botanical Garden’s Conservation Seed Bank and Laboratory of Hawaiian (G. brighamii, G. remyi), New Caledonian (G. aubryi, G. oudiepe), and Tahitian (G. taitensis) species. Seeds were incubated at varying temperatures and in light, and in dark. Key results – We found that (1) seeds of all species tested germinated slowly and only at higher temperatures in the light and dark, (2) seeds have non-deep physiological dormancy, (3) seeds of the Hawaiian species are short lived at conventional seed bank conditions, and (4) only 40% of Gardenia spp. are represented in ex situ facilities, and 66% of the species have not been evaluated for the IUCN Red List. Conclusion – Seeds of Hawaiian Gardenia spp. are short lived in storage. Since seeds germinate in darkness, they are unlikely to form a persistent soil seedbank. Although seeds of all species tested are physiologically dormant, they can be easily propagated from seed at warmer temperatures, giving some hope to the conservation and restoration of the Critically Endangered Hawaiian species. Since our dataset was limited by a lack of continuous viability monitoring, we emphasize the need for initial germination testing and ongoing viability tests to better understand seed longevity. Lastly, we discuss the ecological relevance of our results in the context of the Hawaiian archipelago.

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DOI: 10.5091/plecevo.117464

Authors: Mohamed Hamimeche, Errol Véla, François Gillet, Riadh Moulaï

Abstract: Background and aims – In spite of their proximity to the coasts, the flora of the islands and islets of the Algerian coasts has been poorly studied. This work is the first to provide an overall view of the richness and the determinants of the Algerian island flora. Material and methods – The study is based on a compilation of original floristic data. Two classifications of 30 islands and islets were derived from PCA and HCPC performed on the species occurrence matrix and on a matrix of flora descriptors including species richness, functional traits (life form, seed dispersal, pollination), and biogeographic range. We performed an RDA to explain the variation in flora characteristics by a set of physiographic (longitude, latitude, elevation, area, isolation, steepness index, and area/perimeter ratio) and biotic (seabird density and human presence) variables. Key results – The floristic inventory encompassed a total richness of 295 vascular plant taxa (including subspecies and varieties) on the 30 studied sites. Five main groups of islands and islets can be distinguished based on vegetation composition and three from flora descriptors. RDA model selection revealed that the combination of four variables (seabird density, area, latitude, and longitude) explained 26.6% of the variation in flora characteristics. Taken alone, the density of yellow-legged gull colonies and the island area were the main drivers of this variation. Results showed that floristic richness was associated with larger island area and higher seabird density, the importance of some plant functional traits, such as zoochory and entomogamy, and with a higher proportion of Eurasian holarctic species. Conclusion – In the context of island flora conservation, some of these small islands of Algeria can be considered as “modern refuges” from human pressures, and this is particularly important in the context of Mediterranean ecosystems characterised by a quasi-permanent human impact in various habitats. Two new important plant areas (IPAs) for Algeria are proposed following the results of these floristic inventories.

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DOI: 10.5091/plecevo.96572

Authors: Julian M. Norghauer, David M. Newbery, Godlove A. Neba

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. R2) 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.

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DOI: 10.5091/plecevo.84458

Authors: Federico Tardella, Alessandro Bricca, Maurizio Cutini, Giampiero Ciaschetti, Annarita Frattaroli, Bruno Paura, Gianfranco Pirone, Nicola Postiglione, Andrea Scolastri, Tiziana Panichella, Arianna Ferrara, Andrea Catorci

Abstract: Background and aims – The research aim was to investigate the relation between large-scale geographic factors and the functional structure of the herbaceous layer of calcareous beech forests in the Apennines, managed as high forest.Material and methods – We selected 163 plots (20 × 20 m), ranging from Central to South Italy, using a random stratified sampling design. We correlated the effect sizes of traits’ community-weighted means, functional richness, evenness, divergence, dispersion, and Rao’s quadratic entropy, with the main axes of variation in species composition.Key results – The geographical range played a weak role in shaping the species composition of the herbaceous layer. However, we found evidence of functional convergence towards the northern sectors of the study area, where traits linked to resource retention strategies and vegetative spread are filtered. We did not find any evidence of convergence northwards for leaf phenology and pollination types.Conclusion – The increase of the intensity in the environmental stress was associated with a decrease of diversity for traits related to resource conservation strategies and vegetative propagation. On the contrary, the lower cold stress intensity southwards fostered a better niche partitioning, ensuring the coexistence of species with different modalities of resource acquisition and conservation.

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