ABSTRACT
Beyond the observation of climatic variations and their impact on livelihoods, farmers' knowledge about climate change? can help understand how rural populations respond to environmental changes and what factors should policies consider when planning rural adaptation. This study documents Sereer farmers' observations of local environmental changes in the Fatick region of Senegal and explores how the farmers use crop diversity to adapt to those changes. Their observations of environmental changes were documented through focus group discussions and semi-structured interviews. Variations in crop diversity as well as farmers' explanations for these variations were assessed through surveys in two villages (n=126 households). Sereer farmers identify four distinct periods of similar climate trends and reported how they managed crop diversity in response to the climate variations between periods. Three management responses stand out: abandonment of long-cycle varieties during drought periods, adoption of short-cycle varieties during periods with shorter rainy seasons, and reinstating of long-cycle varieties with the return of rains. Sereer farmers consider that climate variations are important reasons to modify their crop varieties, although variety selection is also affected by other socio-economic and cultural reasons. This study illustrates the contributions that local knowledge can bring to understanding the local impact of climate change on smallholder farmers. Understanding how they use crop diversity to adapt to climate variations can be the bases of climate change adaptation policies that address local needs and constraints.
ABSTRACT
Lathyrus sylvestris is a pioneer legume often found in disturbed habitats. Mainly reproduced through vegetative propagation, this clonal species presents a system of ramets that remain connected for several years. The existence of carbon transfer among ramets within a clone has been studied using 14C in situ. Assimilate translocation from primary to secondary ramets was observed in all clones when the primary ramet was exposed to 14CO2. The amount of transfer ranged from trace up to 90% of the total 14C incorporated. However, in only half of the clones there was consistent enrichment of the secondary ramet (5 to 89%) suggesting that interramets transfer of carbon may be facultative. Furthermore, when significant export occurred from the primary ramet, it was always principally towards only one ramet even when the clone included more than one. The transfer of 14C from secondary to primary ramets was shown to be significant only when photosynthesis of the latter was decreased by shading. In this case import of carbon was never more than 60% of the incorporated 14C.No correlation was found between age or size of the ramets and the intensity of transfer. The shading effect let suppose that transfers are mainly driven by carbon limitation due to changing environmental conditions and not to the state of ramet maturity. The adaptative advantage of such facultative physiological integration between ramets of a clone is discussed.
