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In the Bromeliaceae, hybrids have been engineered for horticultural purposes; in addition, hybrids have been observed in natural habitats. We investigated the hybridization potential of three sympatric species of Tillandsia inhabiting secondary forests and shaded coffee plantations in the central mountains of Veracruz, Mexico. The studied species (T. juncea, T. polystachia and T. variabilis) show overlap in flowering phenology and are believed to share pollinators. We compared the floral morphology of the species, performed controlled intra-and interspecific pollinations, and recorded pollen tube growth, fruit and seed set, as well as seed germination. Flower size differed among the species, but stamen and stigma heights were similar between pairs of species, which would facilitate interspecific pollen exchange. Pollen tubes reached the ovary in interspecific crosses. The three species showed interspecific crosscompatibility, as all crosses resulted in development of mature fruit and viable seeds. Tillandsia juncea achieved the highest fruit set, whereas T. variabilis showed the highest seed set. Seed set as a result of agamospermy, autogamy, geitonogamy and interspecific cross-pollination did not differ among the species. The findings suggest that pre-and post-pollination barriers are weak among the three species of Tillandsia, which thus could potentially hybridize in natural sympatric populations. K E Y W O R D Sfruit and seed set, interspecific crosses, intraspecific crosses, seed germination, Tillandsia species | INTRODUCTIONPlant hybridization involves the mating of two closely or distantly related taxa, followed by the production of viable seeds, germination and growth of seedlings (Marques, Roselló-Graell, Draper, & Iriondo, 2007;Soltis & Soltis, 2009). The genetic and demographic effects derived from hybridization are among the leading causes of population decline (

Abstract:Mexico is a megadiverse country and Veracruz is one of the states with the highest floristic diversity. The reserve of La Mancha in central coastal Veracruz comprises several vegetation types. In this site we conducted for a year, monthly surveys of flowering or fruiting plants in six vegetation types, considering the frequency of occurrence of different species. We found a total of 147 species (131 genera and 63 families). The families most represented were Asteraceae, Fabaceae and Verbenaceae. In addition, we found nine species that had not been reported in previous floristic studies. The highest taxonomic richness was observed in the tropical deciduous flood forest with wetland (59 species), while the highest diversity was found in tropical deciduous forest (SDI = 0.9562). We also found that the most similar vegetation types based on the composition and frequency of species were, coastal dune scrub, tropical deciduous forest and pioneer dune vegetation. The dominant plant biological form in La Mancha were herbs (40.41 %) followed by shrubs (23.97 %), vines-lianas (18.49 %) and trees (17.12 %). This study is the first to consider the frequency-occurrence of flowering and fruiting plants in La Mancha, covering six vegetation types through one year. The more relevant results of this study show the diversity of plants in different environments using the frequency of each species based on reproductive events. This information could be useful in future researches that evaluate plant-animal interactions, like pollination and seed dispersal. Key words: floristic, flowering plants, fruiting plants, La Mancha, Veracruz.Resumen: México es considerado un país megadiverso y Veracruz es uno de los estados con mayor diversidad florística del país. La reserva de La Mancha en la costa central de Veracruz alberga varios tipos de vegetación. En este sitio realizamos durante un año censos mensuales de la vegetación en floración o fructificación en seis tipos de vegetación, considerando la frecuencia de aparición de las diferentes especies de plantas. Encontramos en total 147 especies (131 géneros y 63 familias). Las familias mejor representadas fueron Asteraceae, Fabaceae y Verbenaceae. Además de nueve especies que no habían sido reportadas en estudios florísticos previos. La mayor riqueza taxonómica se observó en la selva baja inundable y el humedal (59 especies), mientras que, la mayor diversidad se encontró en la selva baja caducifolia (SDI = 0.9562). Además encontramos que los tipos vegetación más similares con base a la composición y frecuencia de especies son el matorral de dunas costeras, la selva baja caducifolia y la vegetación pionera de dunas. La forma biológica predominante en La Mancha fueron las hierbas (40.41 %), seguida por arbustos (23.97 %), bejucos-lianas (18.49 %) y árboles (17.12 %). Este trabajo es el primero que analiza la frecuencia-ocurrencia de plantas con flor y/o fruto en La Mancha, abarcando seis tipos de vegetación. Los resultados más destacados muestran la diversidad de plantas en diferent...

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Background: Tropical rain forests have been impacted by land use change, leading to major deforestation and fragmentation. Understanding how fragmentation impacts plant communities is central for tropical conservation. Questions: i) How does species richness vary across a range of fragment sizes, and does it vary with plant size-structure? ii) how are species composition and floristic similarity affected by forest fragmentation? iii) does habitat fragmentation affect the representation of species with different life-history and regeneration patterns? Studied species: We sampled overall plant communities and calculated diversity metrics of mature-forest and light-demanding species, considering plants of different size-categories (defined by diameter at breast height, DBH). Study site: This study was carried out at Los Tuxtlas, Veracruz, Mexico. An area originally dominated extensive evergreen tropical forest, but currently highly fragmented Methods: We sampled plants in five forest fragments representing (2 - 36 ha), and a large patch of continuous forest (700 ha). Within each site we established ten-50 × 2 m transects and registered all woody plants with DBH > 1 cm. Results: Species richness declined as fragment size became smaller. Such decline was significant considering all plants (DBH > 1.0 cm) but became non-significant as plant size-category increased (DBH > 2.5, or > 10 cm.). Small fragments had distinguishable assemblages compared to continuous forest and also a reduction in the representation of mature-forest species compared to light-demanding species. Conclusions: Our findings confirm that fragmentation affects tropical plant species diversity, but the effect is differential, depending on plant size-category and life history.

BackgroundInterspecific interactions play an important role in determining species richness and persistence in a given locality. However at some sites, the studies, especially for interaction networks on adult butterflies are scarce. The present study aimed the following objectives: (1) determine butterfly species richness and diversity that visit flowering plants, (2) compare species richness and diversity in butterfly-plant interactions among six different vegetation types and (3) analyze the structure of butterfly-flowering plant interaction networks mediated by flowers.MethodsThe study was developed in six vegetation types within the natural reserve of La Mancha, located in Veracruz, Mexico. In each vegetation type, we recorded the frequency of flower visits by butterflies monthly in round plots (of radius 5 m) for 12 months. We calculated Shannon diversity for butterfly species and diversity of interactions per vegetation type. We determined the classic Jaccard similarity index among vegetation types and estimated parameters at network and species-level.ResultsWe found 123 species of butterflies belonging to 11 families and 87 genera. The highest number of species belonged to Hesperiidae (46 species), followed by Nymphalidae (28) and Pieridae (14). The highest butterfly diversity and interaction diversity was observed in pioneer dune vegetation (PDV), coastal dune scrub (CDS) and tropical deciduous flooding forest and wetland (TDF-W). The same order of vegetation types was found for interaction diversity. Highest species similarity was found between PDV-CDS and PDV-TDF. The butterfly-plant interaction network showed a nested structure with one module. The species Ascia monuste, Euptoieta hegesia and Leptotes cassius were the most generalist in the network, while Horama oedippus, E. hegesia, and L. cassius were the species with highest dependencies per plant species.DiscussionOur study is important because it constitutes a pioneer study of butterfly-plant interactions in this protected area, at least for adult butterflies; it shows the diversity of interactions among flowering plants and butterflies. Our research constitutes the first approach (at a community level) to explore the functional role of pollination services that butterflies provide to plant communities. We highlighted that open areas show a higher diversity and these areas shared a higher number of species that shaded sites. In the interaction networks parameters, our results highlighted the higher dependence of butterflies by the flowers on which they feed than vice versa. In conclusion, the plant species (as a feeding resource) seem to limit the presence of butterfly species. Thus, this protected area is highly relevant for Lepidoptera diversity and the interaction between these insects and flowering plants. We suggest that studying plant and butterfly diversity in tropical habitats will provide insight into their interspecific interactions and community structure.