Site-to-site variation in species composition (β-diversity) generally increases from low- to high-diversity regions. Although biogeographical differences in community assembly mechanisms may explain this pattern, random sampling effects can create this pattern through differences in regional species pools. Here, we compared assembly mechanisms between spatially extensive networks of temperate and tropical forest plots with highly divergent species pools (46 vs. 607 species). After controlling for sampling effects, β-diversity of woody plants was similar and higher than expected by chance in both forests, reflecting strong intraspecific aggregation. However, different mechanisms appeared to explain aggregation in the two forests. In the temperate forest, aggregation reflected stronger environmental correlations, suggesting an important role for species-sorting (e.g. environmental filtering) processes, whereas in the tropics, aggregation reflected stronger spatial correlations, more likely reflecting dispersal limitation. We suggest that biogeographical differences in the relative importance of different community assembly mechanisms contribute to these striking gradients in global biodiversity.

BackgroundThe Republic of Georgia (Sakartvelo in Georgian language) is part of the Caucasus biodiversity hotspot, and human agricultural plant use dates bat at least 6000 years. However, little ethnobiological research has been published from the region since the 1940s. Given the lack of recent research in the region, the present study we report on plant uses in Skartvelo (Republic of Georgia), Caucasus. We hypothesized that, (1) given the long tradition of plant use, and the isolation under Soviet rule, plant use both based on homegardens and wild harvesting would be more pronounced in Georgia than in the wiser region, (2) the Soviet occupation would have had broad influence on plant use, and (3) there would still be incidence of knowledge loss despite wide plant use.MethodsFieldwork was conducted in Khevsureti, Samtskhe-Javakheti, Tusheti, Svaneti, and Racha in July–August 2013, July–August 2014, and September–October 2015. Interviews using semi-structured questionnaires were conducted with 170 participants (80 women and 90 men) after obtaining their oral prior informed consent. All interviews were carried out in the participants’ homes and gardens by native speakers of Georgian and its local dialects (Svan, Tush, Khevsur, Psav), or, where participants spoke these as their native language, Armenian, Russian, or Greek.ResultsIn the present study we encountered 480 plant species belonging to 249 genera of 95 families being used in the research region. The highest number of species and of unique species were reported from the remote Tusheti-Khevsureti region. Informant consensus and number of use reports were highest for each region in the food and medicinal use categories. Of the 480 plants being used in the research region 282 species were exclusively wild-harvested, 103 were grown in homegardens, and 84 were both grown in gardens and sourced in the wild.ConclusionsPlant species, and uses, found in our study, both for Georgia in general, as well as for its regions, showed clear relations to the wider Caucasus - Asia Minor - Balkans cultural complex. However, plant use in Georgia was much more diverse than reported in other studies from Eurasia.Electronic supplementary materialThe online version of this article (doi:10.1186/s13002-016-0110-2) contains supplementary material, which is available to authorized users.

A thorough review concerning palm uses in tropical rainforests of northwestern South America was carried out to understand patterns of palm use throughout ecoregions (Amazonia, Andes, Chocó), countries (Colombia, Ecuador, Peru, Bolivia), and among the different human groups (indigenous, mestizos, afroamericans, colonos) that occur there. A total of 194 useful palm species, 2,395 different uses and 6,141 use-reports were recorded from 255 references. The Amazon had the highest palm use, whereas fewer, but similar uses were recorded for the Andes and Chocó. Ecuador was the most intensively studied country. Most palms were used for human food, utensils and tools, construction, and cultural purposes. Indigenous people knew more palm uses than mestizos, afroamericans and colonos. The use of palms was not random and the main uses were the same throughout the studied ecoregions and countries. Palms satisfy basic subsistence needs and have great importance in traditional cultures of rural indigenous and peasant populations in our study area. Arecaceae is probably the most important plant family in the Neotropics, in relation to use diversity and abundance.Resumen Se realizó una revisión exhaustiva de los usos de las palmeras en los bosques tropicales lluviosos del noroeste de América del Sur para comprender los patrones de uso de las palmeras por ecorregiones (Amazonia, Andes, Chocó), países (Colombia, Ecuador, Perú, Bolivia) y entre los diferentes grupos humanos (indígenas, mestizos, afroamericanos, colonos) existentes. Se registraron 194 especies de palmeras útiles, 2,395 usos distintos y 6,141 registros de uso a partir de 255 referencias. La Amazonia tuvo el uso más alto de palmeras, mientras que en los Andes y el Chocó se encontraron menores usos aunque similares. Ecuador fue el país que se estudió más intensamente. La mayoría de las especies se usaron para alimentación humana, utensilios y herramientas, construcción y usos culturales. Los indígenas conocieron más usos de palmeras que los mestizos, afroamericanos y colonos. El uso de las palmeras no fue al azar y los usos principales fueron los mismos en todas las ecorregiones y países estudiados. Las palmeras cubren necesidades básicas de subsistencia y tienen una gran importancia en las culturas tradicionales de las poblaciones indígenas y campesinas rurales en nuestra área de estudio. Arecaceae es probablemente la familia de plantas más importante del Neotrópico, en relación a su diversidad y abundancia de usos.

No abstract

No abstract