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In a time of global change, having an understanding of the nature of biotic and abiotic factors that drive a species' range may be the sharpest tool in the toolbox of conservation and management of threatened species. However, such information are lacking for most tropical and epiphytic species due to the complexity of life history, the roles of stochastic events, and the diversity of habitat across the span of a distribution. In this study, we conducted repeated census across the core and peripheral range of Trichocentrum undulatum, a threatened orchid that is found throughout the island of Cuba (species core range) and southern Florida (the northern peripheral range). We used demographic matrix modeling and stochastic simulations to investigate the impacts of herbivory, hurricanes, and logging (in Cuba) on projected population growth rates (λ and λs) among sites. Our study indicates that the Florida population is under high extinction risk and most populations in the core range show less interannual variability, but, with the exception of one population, are also in decline. The peripheral population experienced higher herbivory damage than did the core populations, by a native inflorescence‐crippling fly, Melanagromyza miamensis, and an invasive, mortality‐triggered scale, Diaspis boisduvalii. The latter was found in the Florida population only. Hurricanes increased levels of mortality and had a negative effect on λ. However, λ increased following hurricane events due to increased recruitment and decreased herbivory. Life table response experiments suggest that higher adult survival was the largest contributor to the higher λ observed in the growing Cuba populations, as compared with the population in Florida. Logging simulations in Cuba indicate that populations can maintain stability only if selective logging of host trees occurs at low frequency. Reintroduction of the species in its northern peripheral habitat is needed to ameliorate the threats from sea‐level rise and invasive herbivorous insects to secure the current species' northern, continental range margin. Our study exhibits how vital rates and ecological interactions vary across a species distribution and respond under differing stochastic events. [ABSTRACT FROM AUTHOR]

Floral biology and pollination mechanisms of Cymbidium dayanum, an endangered epiphytic orchid, were investigated in south Kyushu, Japan. The flowering period spanned approximately 4 months from fall to winter, with the inflorescences often blooming asynchronously on each plant and individual flowers commonly lasting for a month. The nectarless flowers are self‐compatible but cannot autonomously self‐pollinate; the orchid needs to attract pollinators by deceit for capsule production. The field observations showed that the flowers were pollinated exclusively by the Japanese honeybee Apis cerana japonica, despite its long flowering period. The worker bees pollinated flowers and/or received the pollinarium on the thorax, while escaping from the labellum chamber. The natural fruit‐set ratios at the population level, an estimate of pollination success, varied interannually but were generally low, as the result of infrequent flower visits by honeybee workers owing to the cold winter climate and the lack of a nectar reward. Because most flowers that were artificially pollinated in the winter successfully developed into capsules, the coldness was not considered a direct cause of the low fruit‐set ratios. Our results explicitly indicate that the bee pollination niche could be available to temperate plant species even during mid‐winter. We inferred advantages for the winter flowering of C. dayanum. We studied floral morphology and pollination mechanisms of the fall‐winter flowering orchid Cymbidium dayanum in south Kyushu, Japan. Our multiple‐year observations indicate that the nectarless flowers are pollinated exclusively by the Japanese honeybee Apis cerana japonica. We discussed the pollination strategy of Japanese C. dayanum, including possible reasons why this orchid continues to flower in winter when flower‐visiting insects are very scarce. [ABSTRACT FROM AUTHOR]

Orchids are generally regarded as plants with an insignificant invasive potential and so far only one species has proved to be harmful for native flora. However, previous studies on Epipactis helleborine and Arundina graminifolia indicate that the ecological aspects of range extension in their non-native geographical range are not the same for all species of orchids. Disa bracteata in its native range, South Africa, is categorized as of little concern in terms of conservation whereas in Australia it is naturalized and considered to be an environmental weed. The aim of this research was to determine the ecological preferences enabling the spread of Disa bracteata in Western and South Australia, Victoria and Tasmania and to evaluate the effect of future climate change on its potential range. The ecological niche modeling approach indicates that most of the accessible areas are already occupied by this species but future expansion will continue based on four climate change scenarios (rcp26, rcp45, rcp60, rcp85). Further expansion is predicted especially in eastern Australia and eastern Tasmania. Moreover, there are some unpopulated but suitable habitats in New Zealand, which according to climate change scenarios will become even more suitable in the future. The most striking result of this study is the significant difference between the environmental conditions recorded in the areas which D. bracteata naturally inhabits and invasive sites—that indicates a possible niche shift. In Australia the studied species continues to populate a new niche or exploit habitats that are only moderately represented in South Africa. [ABSTRACT FROM AUTHOR]

Oeceoclades maculata is the most successful invasive orchid in the Neotropics. The anatomy of the vegetative organs, peduncle and seeds of O. maculata was characterized to identify features of possible physiological and ecological importance. Plants from four locations in Soconusco, Chiapas, Mexico were selected. Transverse, longitudinal and paradermal sections of vegetative organs were observed using light and scanning electron microscopes. Oeceoclades maculata has amphistomatous leaves, with smooth and a thin to slightly thickened cuticle, a single-layered epidermis, a low density of small stomata (<13 mm-2) and numerous sunken glandular hairs on both surfaces. Mesophyll is homogeneous with abundant extravascular fibre bundles. The root has a multilayered velamen with abundant tilosomes. Numerous idioblasts with raphides were observed in leaves, pseudobulbs and roots. The seeds are fusiform, with smooth surfaces and transverse folds. Some of these traits link O. maculata with terrestrial and epiphytic habits and with xerophytic habits, with humid and high light intensity and humid environments. This combination of traits might be a key factor behind the success and expansion of O. maculata. Nonetheless, a detailed characterization of the microhabitats occupied, demography, reproductive strategies and mycorrhizal associations will be essential for understanding the behaviour of this invasive species and, if necessary, designing strategies for its control. [ABSTRACT FROM AUTHOR]

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