Climatic and demographic determinants of vegetation cover in northern Cameroon

Abstract

The objective of the study was to evaluate the spatio-temporal impacts of seasonal rainfall and urban population growth on the variations in normalized difference vegetation index (NDVI) in north Cameroon, which includes climates from south to north, the Sudanese and Sahelian climates. To this end, 48 points of measured rainfall were interpolated based on the kriging method at a spatial resolution of 8 km in accordance with the NOAA-AVHRR NDVI data set. Relationships between rainfall and NDVI, on the one hand, and urban population growth and NDVI, on the other, were analysed considering the 79 administrative units (AUs) in Cameroon. Seasonal (rainy season) variations of the vegetation cover were stud-ied for the period 1987-2002 using the NDVI product at 8 km (NOAA-AVHRR) and 1 km (SPOT-VEGETATION) of spatial resolution. This article emphasizes the importance of the urban signal for the NDVI studies at finer scales, specifically in tropical areas.

Pollination Efficiency of Dactylurina Staudingeri (Hymenoptera : Apidae) on Vernonia Amygdalina (Asteraceae) Florets at Dang (Ngaoundere, Cameroon)

“…of the Faculty of Science, University of Ngaoundéré. This region belongs to the high altitude Guinean savannah agro-ecological zone [23]. The climate is characterized by a rainy season (April to October) and a dry season (November to March), with an annual rainfall of about 1500 mm.…”

Impact of single visit of Chalicodoma cincta Fabricius 1871 (Hymenoptera: Megachilidae) on Ceratotheca sesamoides Endl. 1753 (Pedaliaceae) flowers at Ngaoundéré (Cameroon)

“…The experiment was carried out from June to September, in 2015 and 2016 at Dang within the experimental fields of the Unit for Apply Apidology (latitude: 7°42.264 N; longitude: 13°53.945 E; altitude: 1106 m above sea level) of the Faculty of Sciences, University of Ngaoundéré, Adamawa Region of Cameroon. This region belongs to the high altitude Guinean savannah agro-ecological zone [10]. The climate is characterized by a rainy season (April to October) and a dry season (November to March), with an annual rainfall of about 1500 mm.…”

Floral activity of Apis mellifera (Hymenoptera: Apidae) on Bidens steppia (Asteraceae), Cordia africana (Boraginaceae), Pittosporum viridiflorum (Pittosporaceae) and Psychotria mahonii (Rubiaceae) in Nyambaka (Adamawa, Cameroon)

“…The present study was carried out from March 2017 to November 2018 in Nyambaka, a village located in the South of Ngaoundere, the capital of the Adamawa region of Cameroon. This region is located between the 6 th and 8 th degrees of latitude north and between the 11 th and 15 th degrees of longitude east; it belongs to the high-altitude Guinean Savannah agro-ecological zone (Djoufack et al, 2012). The climate is characterized by a rainy season (April to October) and a dry season (November to March), with an annual rainfall of approximately 1500 mm, a mean annual temperature of 22°C, and a mean annual relative humidity of 70% (Amougou et al, 2015) which are suitable climatic conditions for the beekeeping practice.…”