Nucleated regeneration of semiarid sclerophyllous forests close to remnant vegetation

Natural regeneration of mediterranean plant communities has proved difficult in all continents. In this paper we assess whether regeneration of sclerophyllous forests shows nucleated patterns indicative of a positive effect of vegetation remnants at the landscape level and compare the regeneration patterns between sites with distinctive climate conditions. We studied the spatial patterns of vegetation change during 52 years in central Chile using remotely-sensed images to test the predictions that (1) regeneration of sclerophyllous vegetation expands from patches of remnant vegetation; and (2) regeneration is more dependent on remnant vegetation in drier sites. Our results show that the regeneration of the sclerophyllous vegetation in central Chile is a slow process that may be possible under certain conditions. We found that the fraction of regenerated vegetation increases with the proximity to remnant sclerophyllous forest in an aggregated pattern. Especially in drier sites, vegetation remnants have a facilitative role on the regeneration of mediterranean-type ecosystems. These results have important implications for the management and conservation of these ecosystem

Ancient and modern introduction of <i>Broussonetia papyrifera</i> ([L.] Vent.; Moraceae) into the Pacific: genetic, geographical and historical evidence

<div><p><i>Broussonetia papyrifera</i> (L.) Vent. (Moraceae), or paper mulberry, is a species of cultural importance in South East Asia, East Asia and the Pacific. Originally from mainland South East Asia or East Asia, this plant was introduced into the Pacific range by prehistoric Austronesian voyagers. We used non-coding internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA and inter-simple sequence repeat (ISSR) on 79 samples of <i>B. papyrifera</i> from different islands of Remote Oceania, and South East Asia and East Asia. Our results show an absence of genetic diversity in the introduced range of Remote Oceania, with the sole exception of Hawaii. By contrast, Asian samples show genetic diversity. The data obtained suggest a prehistoric human-mediated introduction of this species from East Asia to Remote Oceania and a second, possibly historic, human-mediated introduction to Hawaii.</p></div

Information retrieved from specimens at Natural History Collections can improve the quality of field-based ecological networks

Numerous studies analyze the interactions between plants and their pollinators in ecological communities using a network approach. However, field studies rarely record all the interactions occurring in the field. In this sense Natural History Collections (NHCs) can provide information on interactions that may have been missed by field sampling. In this study we compare a network based on field sampling with a network based on data retrieved from specimens at NHCs, and we assess the degree to which these two sources of data are complementary. For this we used data available from a bee biodiversity study conducted in Southern Argentina for the South American bee genus Corynura (Halictidae: Augochlorini). Data on the floral associations of the specimens at NHCs were retrieved from the specimens’ labels, as the name of the plant species on which a given bee was captured is often recorded for many specimens at NHCs. Although field sampling recorded an unusually high number of insect-plant interactions, it misses some unique interactions present in the NHCs networks. Some structural properties of these networks are briefly analyzed, and usefulness and limitations of using NHCs data are discussed. We conclude that the information about insect-plant interactions extracted from NHCs could complement field-based data, especially in poorly sampled communities.Fil: González Vaquero, Rocío Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Gravel, A. I.. York University; CanadáFil: Devoto, Mariano. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin