Time filter

Source Type

Neill D.A.,Amazonian State University | Beltran H.,National Major San Marcos University | Quizhpe W.,National University of Loja

Clethra concordia D. A. Neill, H. Beltrán & Quizhpe (Clethraceae), a thin-stemmed shrub or treelet from the sandstone Machinaza plateau in the Cordillera del Cóndor region on the Peru-Ecuador border, is described and illustrated. The new species is distinct from other species of Clethra L. in its small stature and its very small, thick sclerophyllous leaves, which are evidently an ecological adaptation to the highly acidic, nutrient-poor sandstone substrate where it occurs. Source

In Haiti, wood and charcoal are important sources of domestic fuel, and wood-cutting for fuel is a major cause of degradation of the region's dry forests, together with livestock pasturing (cattle and goats). In the Dominican Republic across the border, while the situation was similar some thirty years ago, conditions have changed and dry forests are showing signs of regeneration. The southernmost part of the border area between the two countries, around Anse-à-Pitre and Pedernales, offers an opportunity to compare the condition of dry forests on either side of the border, where the climatic and geological conditions are virtually identical. Our study shows denser tree and shrub cover and higher trees on the Dominican Republic side and a larger number of individual trees regenerating from multiple stems on the Haitian side. In general, the species composition is similar on both sides of the border, but there are significant differences in their frequency and abundance-dominance. Acacia scleroxylon, Amyris elemifera, Bursera simarouba, Capparis ferruginea and Guaiacum sanctum are more frequent in the Dominican Republic, while Acacia macracantha, Senna atomaria, Phyllostylon brasiliense and the two cacti Pilosocereus polygonus and Opuntia sp. are more frequent in Haiti. These differences may be attributed to the autecology of the species (e.g. capacity for colonising disturbed terrain and for vegetative regeneration) rather than to preferences for their use such as for firewood and charcoal. Source

Bartels P.J.,Warren Wilson College | Nelson D.R.,East Tennessee State University | Kaczmarek L.,Adam Mickiewicz University | Kaczmarek L.,Amazonian State University | Michalczyk L.,Jagiellonian University

For many decades the genus Milnesium was thought to consist of a single, cosmopolitan species: Milnesium tardigradum Doyere, 1840. However, recently the genus has been re-evaluated, and numerous new species have been described. Cur-rently, over twenty extant species and one fossil are recognised, and most appear to have very narrow geographic ranges. It is doubtful that M. tardigradum sensu stricto is truly cosmopolitan, but to evaluate this hypothesis, specimens previously identified as M. tardigradum must be re-examined using newly proposed taxonomic characters. As part of the All Taxa Biodiversity Inventory (ATBI) we collected Milnesium specimens from various locations in the Great Smoky Mountains National Park (GSMNP). Two Milnesium species have been evaluated, and one of them, Milnesium bohleberi sp. nov., is new to science. The new species is most similar to M. eurystomum but differs by shorter claws and a shorter, narrower, and more cylindrical buccal tube. The other Milnesium species, very rare in our collection, is morphologically indistin-guishable from Milnesium granulatum Ramazzotti 1962, which was previously known only from Chile, Italy and Roma-nia. Based on the recently revised description of M. tardigradum sensu stricto, this nominal species for the genus has not been found in the GSMNP samples. Copyright © 2014 Magnolia Press. Source

Vasco C.,Amazonian State University
Journal of Agriculture and Rural Development in the Tropics and Subtropics

This paper analyses the determinants for rural Ecuadorian households to participate in community works, to exchange labour, and to use paid labour. The results show that participation in community work is more common among indigenous peoples who are more committed with community and live in areas with relatively high population densities. Exchange labour agreements are more common among indigenous households settled in areas where industrial agriculture has not penetrated yet. Instead, paid labour is used by small and educated households which have access to credit. Source

Chemical characteristics of 36 soil sections under natural forests from the Cordillera Central of the Dominican Republic were analyzed. 20 of them had been taken from interfluves, peaks and ridges, and the other 16 were taken from riparian environments. In the interfluves, acidic soils predominate, with high values of saturation of Al, while at riparian sites there are more slightly acidic soils, without or with low levels of free Al. In riparian environments, soils tend to be less acidic and less Al saturated. The variability of pH and Al saturation is not related to altitude in the study area. In the interfluves, soils at sites with steeper slopes tend to be less acidic, and this probably is due to geomorphologic processes, which influence soil development. © 2015 Universidad de los Andes. All rights reserved. Source

Discover hidden collaborations