Assane Goudiaby

Vegetation and fire readiness in main morphological units of Niokolo Koba National Park (Southeast Senegal)

Abstract Bush fires are the main cause of natural resource degradation in Niokolo Koba National Park. So-called “early fires” or management fires are considered an irreplaceable tool for land management in protected areas. A synthesis of the literature and field observation reveals that plateaus and slopes are the most prone to burning. Fire proneness depends mainly on vegetation characteristics. The main vegetation types on plateaus and slopes are shrub and arboreal savannah, respectively. These savannah types are both dominated by Combretaceae in the ligneous stratum, while in the herbaceous layer species of Poaceae family dominate. The predominance and state of Poaceae in the herbaceous layer are major indicators of fire readiness. It is sought to adopt a strategy for early fire implementation that minimizes impact on natural resources. Any strategy must include an operational system for monitoring herbaceous fuel conditions. Such a system could benefit from new remote sensing technologies when combined with field measurements in the most exposed zones.

EFFECTS OF DIFFERENT PRETREATMENTS ON THE GERMINATION OF Faidherbia albida (DEL.) A. CHEV. SEEDS

SUMMARY The difficulties of using sulphuric acid for removing the physical dormancy of Faidherbia albida seeds have resulted in a search for alternative methods of pretreatment of the seeds. This trial tested the efffciency of 10 alternative pretreatments. The results show that the sulphuric acid, manual scarification and scarification by hot wire, which achieved stable values of over 90% of germination of seeds after eight days, were clearly superior to the use of a seed gun (80% germination after 16 days at the optimal setting of the gun) or of hot/boiling water methods (less than 20% germination after 16 days). Due to the high capacity of seed gun (i.e. around 1 kg/minute), it appears that the gun method, although methods which treat seeds individually result in higher germination percentages, could be a useful way to treat large quantities of seeds. However, the optimal speed of the rotation of the gun must be determined beforehand for each lot of seeds.

Froelichia (Amaranthaceae) — a new generic record and invasive weed for Africa

SummaryFroelichia (Amaranthaceae) is reported from the Sahel of Senegal for the first time. This is a new generic record for Africa and is a cause for concern since the genus is known to be an invasive weed in other countries with warm climates and sandy substrates. The difficulties caused by this taxon are summarised and control measures are suggested.

Développements récents de l’Herbier de Dakar

The DAKAR Herbarium created in 1960 holds approximately 8000 plant specimens. Like many other African herbaria, activities have been greatly limited during the last decade due to lack of funding which again has lead to scientific isolation. As part of a collaboration with the University of Aarhus (Denmark) the herbarium is now being renovated and it will soon be fully operative. The main innovations during the last year included training of researchers, implementation of infrastructure and equipment, and addition of new specimens.