Search results for "Conservation"

Cropping system dynamics, climate variability, and seed losses among East African smallholder farmers: a retrospective survey.

2014

Abstract Climate variability directly affects traditional low input and rain-fed farming systems, but few studies have paid attention retrospectively to the cropping system’s ability to mitigate climate risk. This study analyzes the impacts of rainfall variability on farmers’ seed variety losses over time, considering changes in smallholder farming systems. The cropping system dynamics, in favoring maize at the expense of sorghum and pearl millet, have induced an increasing risk of seed loss during drought. Combining ecological anthropology and climatology, a retrospective survey asking farmers about the period 1961–2006 was carried out at three altitudinal levels (750, 950, and 1100 m) on …

Le rôle écologique des bonobos : service écologique de dispersion de graine en forêt du Congo

2012

Bonobos (Pan paniscus) are threatened with extinction. They are the largest primates, and the only apes (except human), of the southern bank of the Congo Basin. Along with chimpanzees, they are our closest living relatives and are studied by anthropologists to include/understand our hominid origins; but what about their functional role in the forest? Would their disappearance have serious consequences for forest ecology? Answering this question is the aim of this new project, with several years of observations of a free-ranging habituated group of bonobos on the LuiKotale research station (DR Congo). In this tropical rainforest, the very great majority of plants need animals to reproduce an…

The spatial and temporal distribution of carabid and weed seed predation in winter wheat: a comparison between conventional and conservation agricult…

2013

Carabids can be key players in weed seed predation within arable crops under temperate climate. Field management options, because they affect carabid communities, may represent potential levers to increase weed seed predation levels within fields. Among these options, Conservation Agriculture is often presented as a promising management option for carabids but its effect on weed seed predation levels is less clear. In this study, carabids and weed seed predation were monitored using a grid sampling from April till September 2011 in two adjacent winter-wheat fields in North-eastern France, one conducted as no-till with cover crop for 5 years (conservation agriculture) and the other as conven…

Quelles pratiques agricoles pour préserver les peuplements riches en espèces messicoles ?

2016

A consequence of the agricultureal intensification of the second part of the XXth century is the depletion of some species linked to arable fields. These species called “segetal” are considered since 2012 under a National Action Plant (PNA). A survey has been conducted to explore the relationships between these segetal weeds and agricultural practices. It involved 159 farm plots for two years in three regions having contrasted climates, soils and farming systems. Data of species richness are presented in relation to agricultural practices. They cannot allow hierarchical ranking of the most favourable practices, whatever the region, but rather the presence of segetal weeds is associated with…

Capacité des adventices à germer en surface dans diverses conditions

2017

EASPEGESTADINRAAGROSUP; Les espèces annuelles produisent des graines chaque année pour maintenir leur population. Ces graines tombent à la surface du sol. Si aucun travail du sol n’est réalisé (ex. cas du semis direct), les graines doivent germer en surface du sol, exposées aux variations environnementales, et parfois même dans un couvert. Cette étude a permis d’étudier l’effet du non-enfouissement des graines, et des conditions environnementales (humidité, lumière, présence d’un couvert) sur la germination, l’émergence et la croissance de nombreuses espèces annuelles. La germination est réduite (en moyenne, toutes espèces confondues) de 26% lorsque les graines sont laissées en surface, de …

Behind the French National Action Plan in favor of Messicoles, the rare arable weeds

2013

Earliest concerns about weed species disappearing from the fields in France rose in the 70s, but they gained recognition in 1993 only with a scientific meeting entitled: “Are weeds worth protecting?“. Thereafter, the French Ministry of Environment initiated a data collection and expert discussion through the network of the National Botanic Conservatories (scientific structures in charge of the survey and preservation of the wild flora and habitats). This approach recently ended with the release of a 241 pages document presenting the state of the art about 102 species strictly associated with arable lands in France: the “Messicoles” (from Latin words meaning “living in cereals”). In 2009 and…

Towards conservation of the local landraces of faba bean (Vicia faba) in Serbia.

2010

International audience; Today, faba bean (Vicia faba L.) in Serbia is almost an extinct crop, without official data on harvested area or production for decades. However, faba bean survived in certain parts of the country, especially along the rivers Southern and Great Morava, in the centre, and in Backa, in the north. In these parts, faba bean is cultivated mostly to suit one's own needs and sporadically is brought to green markets. It is grown as a garden crop, with sowing either in spring or during winter in order to achieve faster growth in comparison to the first schedule. First steps towards the conservation of faba bean local landraces in Serbia have been made within the multilateral …

Travail du sol et gestion du désherbage

2014

Toward a better prediction of in-field weed regulation by carabid beetles in European arable landscapes

2019

International audience; Arable agriculture is still highly reliant on herbicides to manage weeds. As part of the necessary shift towards a reduction in pesticide use, the regulatory effect of seed-eating carabid beetles on weeds has received increasing attention in agroecological research. While strong evidence points to carabids exerting a regulatory effect on certain weed species, it is difficult to predict whether a particular assemblage of carabid species will drive the function of weed seed predation in field conditions. There are also uncertainties about which key local and landscape-scale factors affect the function of weed seed predation. In this paper, we report on specific researc…

Weed flora evolution in direct seeding under cover systems

2018

Direct seeding under cover, by its emergent properties, raises new questions of research on weed communities. The absence of soil disturbance and the implementation of cover crops, modify all factors of conventional agriculture and lead to a complete change of habitat for and management of the weed flora. In addition, these systems allow the development of a certain number of animal communities that interact with one another and with plant communities and thus potentially promote the regulations expected in Agroecology. Finally, there is the issue of annual weed species diversity in systems where tillage is strongly reduced. This thesis, started in November 2017, has as main objective to pr…