Lautaro Hilbert et al.
viernes, 30 de noviembre de 2018
Evidence for mid-Holocene rice domestication in the Americas
Lautaro Hilbert et al.
Lautaro Hilbert et al.
The development of agriculture is one of humankind’s most pivotal achievements. Questions about plant domestication and the origins of agriculture have engaged scholars for well over a century, with implications for understanding its legacy on global subsistence strategies, plant distribution, population health and the global methane budget. Rice is one of the most important crops to be domesticated globally, with both Asia (Oryza sativa L.) and Africa (Oryza glaberrima Steud.) discussed as primary centres of domestication. However, until now the pre-Columbian domestication of rice in the Americas has not been documented. Here we document the domestication of Oryza sp. wild rice by the mid-Holocene residents of the Monte Castelo shell mound starting at approximately 4,000 cal. yr bp, evidenced by increasingly larger rice husk phytoliths. Our data provide evidence for the domestication of wild rice in a region of the Amazon that was also probably the cradle of domestication of other major crops such as cassava (Manihot esculenta), peanut (Arachis hypogaea) and chilli pepper (Capsicum sp.). These results underline the role of wetlands as prime habitats for plant domestication worldwide.
.
.
jueves, 29 de noviembre de 2018
miércoles, 28 de noviembre de 2018
.
Useful wild plants are surprisingly poorly protected
.
https://blog.ciat.cgiar.org/wild-coffee-plants-christmas-trees-and-chocolates-tree-are-surprisingly-poorly-protected/
.
Useful wild plants are surprisingly poorly protected
" A new way of measuring plant conservation shows that a wide range of wild plants used for food, medicine, shelter, fuel, livestock forage and other valuable purposes are at risk...
...The Useful Plants Indicator scores almost 7,000 useful wild plants from 220 countries on a scale of 1-100, with 100 meaningfully protected. Any plant rated 75 or higher is “sufficiently conserved.” Low, medium and high priority for conservation is reflected by scores of 74-50, 49-25 and 24-0, respectively. The indicator equally weighs in situ plant conservation – in protected areas like national parks – and ex-situ conservation, which covers plants safeguarded in gene banks, botanical gardens and other conservation repositories."
..
https://blog.ciat.cgiar.org/wild-coffee-plants-christmas-trees-and-chocolates-tree-are-surprisingly-poorly-protected/
.
martes, 27 de noviembre de 2018
lunes, 26 de noviembre de 2018
LA CRISIS CLIMÁTICA VISTA DESDE LA PERSPECTIVA AGROECOLÓGICA
LA CRISIS CLIMÁTICA VISTA D... by on Scribd
domingo, 25 de noviembre de 2018
sábado, 24 de noviembre de 2018
Organic farming at local and landscape scales fosters biological pest control in vineyards
Lucile Muneret Arthur Auriol Denis Thiéry Adrien Rusch
Lucile Muneret Arthur Auriol Denis Thiéry Adrien Rusch
While organic farming practices, which are often promoted as models of ecological intensification, generally enhance biodiversity, their effects on the delivery of ecosystem services, such as biological pest control, are still unknown. Here, using a multi‐scale hierarchical design in southwestern France, we examined the effects of organic farming and seminatural habitats at the local and landscape scales on biological control services of three pests, including weeds and insects, in 42 vineyards. Organic farming at the local and landscape scales was beneficial to the mean and temporal stability of biological control services, while the proportion of seminatural habitats in the landscape reduced the level of biological pest control potential. The effects of organic farming and seminatural habitats across spatial scales varied with the type of prey considered and with time. Egg moth removal rates were higher in fields under organic management compared to conventional management while weed seed removal rates increased with the proportion of organic farming in the landscape. Larval removal rates as well as seed removal rates were always more stable within time in organic fields than in conventional fields. Moreover, independently of farming system type, local variables describing the agricultural management intensity, such as pesticide use or crop productivity, were also found to be important variables explaining levels of biological control services. Pesticide use tended to reduce biological control potential, while crop productivity was associated with contrasting biological control responses depending on the pest type. Our study demonstrates the need to target multiple spatial scales and to consider farming practices, as well as the proportion of seminatural habitats, to design functional landscapes that optimize biological pest control services.
.
.
.
viernes, 23 de noviembre de 2018
.
--------------------o--------------------
.
.
Therefore, we attempt-to treat the same problem with several alternative models each with different simplifications but with a common biological assumption. Then, if these models, despite their different assumptions, lead to similar results we have what we can call a robust theorem which is relatively free of the details of the model. Hence our truth is the intersection of independent lies.
.
Richard Levins. 1966. The strategy of model building in population biology.
.
.
Richard Levins. 1966. The strategy of model building in population biology.
.
--------------------o--------------------
.
Suscribirse a:
Entradas (Atom)






