Working for birds in Africa

Geography

Wed, 01/23/2013 - 17:57 -- abc_admin
Tabalak_wetland_Niger

Tabalak wetland, 70 km north-east of Tahoua, Niger

Image Credit: 
Joost Brouwer

General

The Republic of Niger is a vast landlocked country on the southern edge of the Sahara, with a land area of 1,267,000 km2: more than 5 times the UK, almost 2.5 times France and one-eighth the USA. It is bordered by Benin and Nigeria to the south, Chad to the east, Libya and Algeria to the north, and Mali and Burkina Faso to the west. It measures 1,500 km from Lake Chad in the east to Burkina in the west. The population of Niger is approximately 12 million, at an average density of 9.5 people per km2, with an annual growth rate of 3%. However, due to lack of rainfall the northern three-quarters of the country is largely unsuitable for agriculture. As a result some 85% of the population live in the southern fifth of the country, a narrow band 100 - 150 km wide bordering Nigeria, Benin and Burkina Faso. Here the average population density is about 41 people per km2, as compared with 2 per km2 in the north.

The country is divided administratively into seven Départements, plus the capital Niamey. Niamey, which lies in the southwestern corner of the country, is by far the largest city, with more than 1 million inhabitants. More than 50% of the population of Niger is of Houssa origin. The Houssa are found mostly along the border with Nigeria, but also in the Tahoua area and the Aïr. The Djerma and Songhai are found mostly in the south-west. Other important groups include the Kanouri (mostly in the east), the Touareg (mostly in the north), and the Peul (throughout the country).

Infrastructure in Niger is limited. There is one sealed road that runs west-east from the border with Burkina Faso to Lake Chad. This road has four sealed branches starting in Niamey: north-west along the Niger River to Tillaberi and the border with Mali; north to Ouallam; east and north to Baleyara and Fillingué; and south to Say. There is also a sealed branch from Dosso south to the border with Benin, and from Birni N'Konni north to Tahoua, Agadez and Arlit. Short sealed sections lead from Birni N'Konni, Maradi and Zinder south to the border with Nigeria. The Zinder-Agadez road may by now also be sealed.

Climate, landscape and vegetation

The climate of Niamey can serve as a guide to the climate in the rest of the country. It is a monsoon climate, with 600 mm of rain falling during one rainy season from May-September. Because rainfall generally occurs in heavy or extremely heavy downpours of at times more than 50 mm an hour, much of the rain does not enter the soil where it falls but runs off instead. Because of this, and because of the high temperatures during the rainy season, crops often experience drought stress in spite of the considerable amount of rain falling. Further north the rains are less, and the rainy season shorter than in Niamey. Further south the rains are more plentiful and last longer.

In Niamey the average daily maximum temperature during the rainy season is 35oC and the average daily minimum at night 23oC. From November to February it is very pleasant, with average maximum temperatures still at 35oC but with very low humidity, while at night it cools off to a pleasant 17oC on average. Only the months of March and especially April and May are rather uncomfortable for weeks on end, with average daily maxima exceeding 40oC, high humidity in the build-up to the rains, and night temperatures still at 25-26oC. Heavy dust storms can also occur during this season. Everyone is happy when the first rain actually falls.

Weather-wise October to February are clearly the best months for visiting Niger. Most Palearctic migratory birds are present then, too. For many intra-african migrants you need to come during the rains when the bush and fields are green. You wonder where all the stories about famine in the Sahel come from until you find out that the average millet grain harvest is only 250-400 kg per hectare in good years. This really is living on the edge in many cases. A bit of income from eco-tourism is most welcome.

Niger is a relatively flat country with most land lying between 200 and 500 m above sea level. The geological formations immediately underlying these lowlands are mostly horizontal Tertiary sediments. Large plateaux are formed where these sediments are capped by erosion-resistant laterite. The extensive, more low-lying parts of the landscape are generally covered by layers of wind-deposited sands of varying thickness. Major areas of upland are the extremely scenic Aïr mountains in the central north (highest point 2,022 m); the Djado plateau in the north-east (c.800 - 1,000 m); and the much smaller Termit range in the central east (highest point 710 m). Due to their height these areas receive more rainfall than the surrounding lowlands. The vegetation of the mountainous areas is relatively varied and contains some Mediterranean and Afromontane elements. Characteristic woody species in Aïr include Acacia spp., Rhus tripartita, Ficus salicifolia, Salvadora persica and Ziziphus and Balanites spp. The wild olive Olea laperrinei still occurs.

Except in highland areas, isohyets and ecological and bio-geographical zones in Niger run in parallel, more or less west-north-west to east-south-east. The north of the country, where average annual rainfall is less than 100 mm, is occupied by the Sahara desert. This zone includes huge tracts of sand dune areas as well as gravelly plains and rocky areas. Vegetation is very sparse and localised and mostly limited to annuals such as Stipagrostis spp. and Tribulus longipetalus. Along sand-filled dry river beds, lines of Acacia raddiana trees may be found and following rainfall, a carpet of annuals.

Further south lie the Sahelian grasslands, which receive about 150 - 350 mm of summer rainfall (June-August). These grasslands form an integral part of extensive livestock grazing systems. Dominant grass species vary according to local conditions but include Panicum, Sorghum, Cenchrus, Aristida and Schoenefeldia species. Further south, perennial grass and sedge species such as Aristida pallida and Cyperus conglomerata are also found. Trees and shrubs are rare in the northern part of this zone but include Acacia, Maerua and Balanites species. In the south of the Sahel the landscape becomes more wooded with Combretum, Boscia, Guiera, Sclerocarya and Commiphora species.

In the southern Sahelian zone (annual rainfall 350 - 600 mm, June-September) millet and sorghum fields now predominate over wide areas. The natural vegetation contains a variety of Combretaceous and other woody species, including Hyphaene palm trees in less dry situations. The herb layer is very varied and includes grasses, legumes and other species. The climax vegetation on the lateritic plateaux is the so-called 'tiger bush'. This consists of bands of dense woody vegetation up to 6 m high (mostly Combretaceae and Acacia spp.) separated by strips of bare crusted soil tens of metres wide. The bare strips enable the adjacent woody vegetation to survive by providing it with run-off.

The extreme south of Niger lies within the northern Sudanian zone (annual rainfall 600 - 800 mm, May-October) and is the mostly densely populated. The natural vegetation is a varied open woodland, which includes baobab Adansonia digitata, Bombax costata, Proposopis africana and various Combretaceae. Gallery forests, containing e.g. Khaya senegalensis, occur along major water courses.

The main wetland area in Niger is formed by the Niger River and its floodplains, which traverse the extreme south-west of the country for a length of 550 km. Fringing vegetation originally included dense stands of Borassus aethiopum palms. Almost all of these have now been felled. The hydrology of the river has also greatly changed over the past thirty years due to the construction of dams in Mali and Guinea. That part of Lake Chad that lies in a basin in south-east Niger was dry for a number of years until 1998. The flow of the basin's main affluent, the Komadougou Yobé, has greatly diminished. Again, this is attributable in large part to the construction of dams on the upper reaches of the river, in this case in Nigeria.

There are more than 1,000 isolated wetlands in Niger, ranging from several tens to more than 2,000 ha in size. Most are run-off dependent, and are found south of a line from the corner of the border with Mali east-south-east to Lake Chad. Some isolated wetlands in Niger hold water for only a few months after the end of the rainy season, others retain water year-round. Aquatic vegetation, where present, can range from dense fringing stands of Acacia nilotica and Mitragyna trees to various herbaceous zones with Vetiveria, Cyperus, Oryza, Polygonum, Echinocloa, Ludwigia and Vossia species, plus dense patches of waterlilies Nymphaea spp. in deeper parts. In the north of the country wetlands include areas of usually dry riverbeds and a number of oases. Palm trees often occur around these oases along with Tamarix spp. and sometimes an emergent vegetation of Typha and Phragmites spp.

Some 1,200 plant species have been recorded in Niger of which four are considered endemic. About 130 species of mammals have been recorded. Of these, Addax nasomaculatus (Critical) and Oryx gazella dammah may already be extinct nationally.

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