7 research outputs found

    Adaptation of a widespread epiphytic fern to simulated climate change conditions

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    The response of species to climate change is generally studied using ex situ manipulation of microclimate or by modeling species range shifts under simulated climate scenarios. In contrast, a reciprocal transplant experiment was used to investigate the in situ adaptive response of the elevationally widespread epiphytic fern Asplenium antiquum to simulated climate change conditions. Fern spores were collected at three elevations and germinated in a greenhouse. The sporelings (juvenile ferns) were reciprocally transplanted to each collection site. Growth and mortality rates were monitored for 2 years. Wild sporelings were monitored at two sites to assess possible transplant effects. Habitat suitability, indicated by overall growth and survival patterns, declined as elevation increased. Only the highland population showed significant adaptation to the ‘‘home’’ habitat, achieving the highest survival rates. Microclimate data suggest that the presumed genetic adaptation at the highland site occurred mainly in response to drought stress in winter. Based on our previous study on species distribution models, which projected an expansion in the range of A. antiquum under future climate change scenarios, the populations at the upper margins of the species’ elevational range may play an important role during this expansion, given their better adaptation to the shifting marginal conditions. Our study suggests that infraspecific variation should be considered when determining the potential impact of climate change on biodiversity

    A transcontinental comparison of the diversity and composition of tropical forest understory herb assemblages

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    Although tropical forests are renowned for their high plant diversity, to date there has been no global quantitative evaluation of the local species richness of terrestrial forest herbs in tropical forests. In this paper, richness and composition of terrestrial herb assemblages is compared in tropical forests of America, Africa and South East Asia. We established 86 non-continuous transects of 445 m each. Herb species richness was analysed and compared to six environmental parameters using minimal adequate regression models and simultaneous autoregressive models. At the global scale, we found a close relationship between herb species richness and temperature parameters, with no differences between continents. The subdivision into three main taxonomic groups (ferns, monocots, dicots) showed that each group has distinct relations to environmental factors and differences in richness between continents. Most of the 72 families found have pantropical distributions but 12, 11, and 16 families were significantly over-represented in America, Africa, and Asia, respectively. Although total species richness was closely related to climatic factors, ferns, monocots and dicots were represented by distinct sets of families with varying species richness on each continent. Which species are found at a given site may thus reflect group-specific evolutionary and historical factors

    Retinal Glia

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