Species traits related to the invasion of woody plants in Patagonian deciduous forests.

The comparison of ecological, phenological, morphological and developmental traits between exotic invasive species and coexisting native species contributes to understand the driving mechanisms of successful invasions. This study aimed to examine which of these traits are related to the invasion of woody plants in the understory of deciduous North Patagonian forests of Argentina. We compared the phenology, shoot growth rate, number of leaves, biomass allocation, leaf herbivory, and recruitment type of two exotic deciduous trees, Crataegus monogyna and Sorbus aucuparia, with those of four coexisting native woody species (one deciduous, one semi-deciduous, and two evergreen species). Spring shoot growth took place several weeks earlier in both exotic species and in the deciduous native species than in the other native species; growth rates were higher in the exotics. Compared to coexisting native species, both exotic species developed shoots that were as long as or longer, had lower biomass allocation to leaves and higher allocation to roots, suffered lower leaf damage by herbivores and exhibited higher seed than vegetative recruitment. This study supports the idea that a combination of phenological, growth rate and mass allocation traits allow exotic species to preempt resources, thus favouring invasion processes.

Cashmirins A and B, new antifungal and urease inhibitory prenylated coumarins from Sorbus cashmiriana

Abstract Cashmirins A (1) and B (2), new prenylated coumarins, have been isolated from the EtOAc- soluble fraction of the whole plant of Sorbus cashmiriana Hedlung, Monog. along with seselin (3), scopoletin (4), 3-hydroxyxanthyletin (5) and luteolin (6), reported for the first time from this species. Their structures were elucidated by spectroscopic techniques including MS, 1D and 2D NMR spectroscopy. Both new compounds 1 and 2 were investigated for biological activities and showed significant antifungal and urease inhibitory activities. Compounds 1 and 2 exhibited significant activity against Aspergillus flavus, Macrophomina phaseolina, Trichophyton simii, Trichophyton schoenleinii, and Pseudallescheria boydri. Both compounds also exhibited significant inhibitory activity against Jack bean urease with IC50 values of 28.2±0.12 µM and 30.3±0.18 µM, respectively compared to thiourea used as positive control.

How training citizen scientists affects the accuracy and precision of phenological data.

Monitoring plant and animal phenology is a critical step to anticipating and predicting changes in species interactions and biodiversity. Because phenology necessarily involves frequent and repeated observations over time, citizen scientists have become a vital part of collecting phenological data. However, there is still concern over the accuracy and precision of citizen science data. It is possible that training citizen scientists can improve data quality though there are few comparisons of trained and untrained citizen scientists in the ability of each to accurately and precisely measure phenology. We assessed how three types of observers-experts, trained citizen scientists that make repeated observations, and untrained citizen scientists making once-per-year observations-differ in quantifying temporal change in flower and fruit abundance of American mountain ash trees (Sorbus americana Marsh.) and arthropods in Acadia National Park, Maine, USA. We found that trained more so than untrained citizen science observers over- or under-estimated abundances leading to precise but inaccurate characterizations of phenological patterns. Our results suggest a new type of bias induced by repeated observations: A type of learning takes place that reduces the independence of observations taken on different trees or different dates. Thus, in this and many other cases, having individuals make one-off observations of marked plants may produce data as good if not better than individuals making repeated observations. For citizen science programs related to phenology, our results underscore the importance of (a) attracting the most number of observers possible even if they only make one observation, (b) producing easy-to-use and informative data sheets, and