Developing reference criteria for the ecological status of West African rivers

Awareness of sustainable management of water and its biological resources is rising in West Africa, but application of effective tools for biomonitoring and detecting habitats at risk in aquatic ecosystems is limited. In this study, we provide key environmental descriptors to characterize reference sites by applying the following "a priori criteria" (physical and chemical, hydro-morphological, and land use parameters) by exploring their potential to determine suitable reference sites. Using data collected from 44 sites, we identified 37 criteria that reliably identify reference conditions in semi-arid rivers by reflecting the impacts of multiple pressures ranging from low to very high intensity of human uses and impairments. We integrated all these impacts in an overall pressures index, which showed that protected areas can reasonably be considered as credible reference sites as far as they show low overall impact levels from cumulative pressures. We recommend that development of bio-indicator standards should be based on the collection and integration of all the available information, especially quantitative, spatially-explicit data, from benthic macroinvertebrates and fish. Rigorous standardization of bio-indicator protocols will make them more easily applicable for management and conservation of aquatic ecosystem resources in semi-arid zones of Africa

Phénologie de la reproduction du Vautour charognard Necrosyrtes monachus en zone soudano sahélienne (Garango, Burkina Faso), 2013–2015.

Twenty nests of the Hooded Vulture Necrosyrtes monachus at Garango, east-central Burkina Faso, were regularly visited (mean 16 visits per nest) during the breeding period from 8 October 2013 to 15 May 2014, to determine the reproductive phenology. During the following breeding season (2014–15) 56 nests were studied to confirm the results obtained the previous season. Most nests were re-used old ones. During the 2013–14 breeding season, pairing and nest building were observed from the end of September 2013. The first clutches were observed from 30 October, with most laid in November and December 2013. In the 13 successful nests, hatching occurred after 45–52 days of incubation. Brooding of the 13 young which eventually flew lasted 3–4 months. During the 2014–15 breeding season, the 45 breeding pairs arrived in the breeding area from September 2014, 41 of the 45 clutches were laid before 28 December 2014, 31 of the 37 clutches which hatched did so before 31 January 2015, 26 of the 33 broods which flew did so before 3 May 2015 and the seven others before 20 May. These results confirm in most respects earlier studies in West and East Africa