The underlying factors stated above are responsible for threats on Biodiversity which are categorized into three major areas:

1.2.2.0 Habitat Degradation

 

1.2.2.1 Unsustainable Agricultural practices

 

Conversion to agriculture is also occurring in many protected areas, in community-owned land, and in state-managed forests without control. Rainforests and savannah woodlands are under the greatest threat from agricultural conversion. Communities in and around protected areas continue to encroach on these protected areas in total disregard to their protection status. Until more sustainable agricultural practices are put in place, the process of slash-and burn agriculture continues, since tropical soils under cultivation can only support crops for a few years before becoming depleted, thereby requiring the clearing of new lands for continued harvests. Mangroves are also heavily harvested for fuel-wood and for construction materials. USAID (2008) also reported that degradation of habitats and loss of species is not always as visible as out-and-out conversion, but it occurs in other more insidious ways with equally damaging results.

In areas where particular species, such as hardwood trees, rattans, medicinal and food plants, and other non-timber forest products, are harvested unsustainably, not only are these species lost but also a myriad of associated plants, such as insects and fungi, that require these specific hosts to meet their own ecological requirements for survival.

 

Furthermore, Nigeria's wildlife is rapidly declining due to habitat loss and increased pressure from hunters, poachers, and bush burning. Animals that have disappeared from Nigeria include the Giant Eland (Taurotragus derbianus), the Giraffe (Giraffa camelopardalis), Black Rhino (Diceros bicornis), Cheetah (Acinonyx jubatus) and the Pygmy hippopotamus (Choeropsis liberiensis. About 10-12 species of primates, including the white throated guenon and sclater's guenon, are under serious threat of extinction.

 

1.2.2.2 Unsustainable harvesting of bio resources

 

Intense harvesting can result in extremely rapid declines in species populations (Kemp and Palmberg, 1993), stated that unless carefully planned and controlled, harvesting may severely damage stand structure, site capacity and regeneration of rainforests. Nnabuife (2003) stated that people cut trees indiscriminately; they do not know that one day, they are going to run out of these trees and it is already happening in some countries. In Nigeria, the Iroko, Ebony, Mahogany and Obeche, are already running out of stock.

 

Illegal hunting of all species of ungulates, takes place at all times of the year, and many of the hunters show no regard to sex, age or reproductive condition of their quarry. According to Happold (1987), illegal hunting is considered to be one of the main reasons for the decline in the populations of all artiodactyls, primates, large rodents, carnivores, rhinoceroses and elephants. The demand for bush meat has increased as human populations have also increased and as a consequence intense hunting pressure has caused a decline in the population of many bush meat species in all parts of Nigeria (Agbelusi, 1994; Happold, (1987). Ayeni (1985) posited that Nigeria has an extensive inland water mass of about 12.5 million hectares that can produce over 500,000 tons of fish under adequate management. According to Anon (1984) Nigeria needs 1.6 million tonnes of fish protein annually but her national fish output is only 400, 000 tons annually, due to unsustainable harvesting practices and incidences of pollution.

 

1.2.2.3. Extractive Industries and their activities

 

Extractive industries in Nigeria are those companies that search for, and exploit resources which are naturally stocked in the earth’s crust. Some of the non-renewable resources of Nigeria that are regularly exploited include crude oil and gas; the nation’s major source of energy and foreign earning, solid minerals, and salts. The petroleum industry accounts for over 90 percent of Nigeria’s national income. The Niger Delta is the seat bench of oil and gas production in Nigeria. Virtually all aspects of oil and gas exploration and exploitation have deleterious effects on the ecosystem and local biodiversity.

 

Nenibarini (2004) reported that seismic activities through massive dynamiting for geological excavation have had serious effects on the nation’s aquatic environment. The use of dynamites produces narcotic effect and mortality of fish and other fauna. 

The destabilization of sedimentary materials associated with dynamite shooting also causes increment in turbidity, blockage of filter feeding apparatuses in benthic fauna and reduction of photosynthetic activity due to reduced light penetration.

 

The process of burying of oil and gas pipelines in the Niger Delta is equally known to fragment biodiversity rich ecosystems such as rainforest and mangroves. Apart from the reduction in habitat area, clearing of pipeline track reduces natural populations, which might in turn distort breeding.

 

Oil spillages occur routinely in the Niger Delta. Sources of oil spill are varied, including, pipeline leakage and rupturing, accidental discharges (tank accident) discharges from refineries and urban centres. There are also biogenic sources of hydrocarbons. Detailed statistics of oil spillage as reported by UNEP in 2011, in Ogoni land of the Niger Delta

(2006-2011). The recent UN Report on Shell Petroleum Development Company (SPDC) and Ogoni land released in August 2011 revealed that the occurrence of oil spills on land brings about fire outbreak that leads to the killing of vegetation and creation of crust over the land, making remediation and re-vegetation very difficult (UNEP,2011).

It was further reported that areas directly impacted by oil spills will be damaged, and root crops, such as cassava, will become unusable. When farming recommences, plants generally show signs of stress and yields are reportedly lower than in non-impacted areas.

 

Oil exploration in the Niger Delta and in coastal areas, gas emissions and other pollutants from the petroleum industry have therefore caused considerable environmental pollution and forest degradation, thus biodiversity of Nigeria. The overall effects of oil on ecosystem health and biota are many. Oil interferes with the functioning of various organs and systems of plants and animals. It creates environmental conditions unfavourable for life.

 

 

1.2.3 Unsustainable Natural Resource Harvesting

 

1.2.3.1 Poaching

 

Poaching is the main threat to large mammals but habitat loss (mainly due to farming) is probably the main threat to biodiversity. The demand for ivory is increasing and Nigeria’s elephants are declining rapidly. Poaching and /or illegal hunting of all species of ungulates, takes place at all times of the year, and many of the hunters show no regard for sex, age or reproductive condition of their quarry. According to Happold (1987), illegal hunting is considered to be one of the main reasons for the decline in the populations of all artiodactyls, primates, large rodents, carnivores, rhinoceroses and elephants. The demand for bush meat was increased as human populations have increased and as a consequence intense hunting pressure has caused a decline in the population of many bush meat species in all parts of Nigeria (Agbelusi, 1994; Happold, (1987).

 

1.2.3.2 Fuelwood consumption

 

About 70% of Nigerian households mainly in rural and semi-urban areas depend largely on fuel wood consumption for their domestic and to a large extent commercial energy needs. The demand for fuel-wood is higher in the less vegetated north and in urban cities where most poor who cannot afford other cost of other sources of energy supply use fuel wood for food production. 

 

Charcoal production is also in high demand from the highly populated cities and is the most critical cause of forest degradation in some parts of the country. With growing population, increasing poverty and relatively low industrialisation rate, Nigeria should develop mechanism to expand the scope of energy requirements in rural and semi-urban areas as part of the strategies to save biodiversity and increase the size of the national vegetation cover.

 

1.2.3.3 Illegal Logging

 

Intense harvesting can result in extremely rapid declines in species population, Kemp and Palmberg (1993) stated that unless carefully planned and controlled, harvesting may severely damage stand structure, site capacity and regeneration of the rainforest.

Fig. 4 Logs of wood extracted from the forest. Source: NCF

Illegal logging and the international trade in illegally logged timber is a major problem for many timber-producing countries in the developing world, particularly in West Africa. It causes environmental damage, costs governments billions of dollars in lost revenue, promotes corruption, and undermines the rule of law and good governance and in some instances, provides funding for specialized crimes such as terrorism. Illegal logging also retards sustainable development in some of the poorest countries of the world. Consumer countries contribute to these problems by importing timber and wood products without ensuring that they are legally sourced. In recent years, however, producer and consumer countries are collaborating to address illegal logging.

 

The Nigerian Government is currently concerned about rising deforestation and environmental degradation, which is estimated to cost the country over $6 billion a year. However, government has failed to put in place effective measures to curb illegal logging and only 6% of the land area is protected. Timber concessions have been granted in some of its forest areas and oil-palm plantations have replaced forest areas. Previous governments have tried to prevent further forest loss through the on log exports, so as to promote agro-forestry and communities based conservation schemes and also encourage the establishment of plantations and reforestation of logged areas. The successes of these initiatives have however been limited.

 

Large areas of natural forests are being exploited for species such as Khaya spp., Nauclea diderrichii (opepe), Terminalia ivorensis (Odigbo), Terminalia superba (Afara) and Triplochiton sceleroxylon (Obeche). High intensity of logging and illegal exploitation of these and other species have continued to pose serious threats to the country’s forest resources. The tree-fall gaps in logged areas has also led to the establishment of secondary growth that often cannot fully replicate the lost trees and the demand for commercial timber does not allow for natural regeneration. There is also the case of genetic erosion, when the largest and most vigorous trees are selectively logged, leaving the genetically poor trees behind to reproduce.

 

The on-site conversion of logs into lumber using chainsaws (Chainsaw milling), is supplying a large proportion of local timber markets with cheap lumber. While it offers socio-economic opportunities to local people, it is often associated with poor timber quality and it also encourages corruption and other illegalities. Regulating and controlling the practice has therefore become a great challenge in the country due to the mobility of these chainsaw milling operations.

 

The Wildlife Conservation Society (WCS) brokered an agreement between Nigeria and

Cameroon, in September 2008, to protect the habitat of the endangered Cross River gorilla by cracking down on illegal logging and the bush meat trade, by strengthening and improving law enforcement and monitoring in the Cross River National Park (Nigeria) and Takamanda National Park (Cameroon). In addition, the two countries agreed to increase community involvement in conservation activities as well as strengthening conservation education and public awareness on conservation. Nigeria is also a signatory to the Accra Declaration which resulted from a FAO/ITTO workshop held in Accra, Ghana in July 2008, which explored the problems and possible solutions to the illegal extraction of forest resources in tropical West Africa (ETRN, 2011).

 

1.2.3.4 Uncontrolled, Illegal and Bad Mining Practices

 

The history of mining activities in Nigeria dates back to the tin mines on the Jos Plateau, for tin and bauxite and the coal mines of Enugu. The tin deposits on the Jos plateau had been extracted through open cast mining, until when surface deposits were depleted. Today, deeper underground ores cannot be extracted economically as world market prices of tin have fallen. This has left the coast clear for artisanal and illegal miners to flourish. The mining of coal on the other hand, was stopped in favour of cleaner energy sources such as oil and gas. Since the withdrawal of foreign investment in the 1970’s, the contribution of the mining sector to the GDP dropped to less than 1% (Seven Year Plan, 2002). The emphasis on mining also changed from big foreign companies, to small local companies and artisan miners who provided raw materials for the local market.

The local mining and processing of these raw materials have had major socio-economic, infrastructural development of these areas, associated with major negative physical, biological, hydrological as well as environmental impacts on these areas.

 

Small-scale, largely illegal mining have had similar widespread negative impacts in most other areas in Nigeria. Sumaila (1989) reported that tin mining activities which have caused considerable erosion damages to lands arising from active gully equal to 7, 240km in length. The influx of mining operators without adequate monitoring of production and documentation does not augur well for conservation of the vegetation cover, minerals and land use systems. The erosion problem created in the mining sites is on a steady increase, leading to development valleys. Solid mineral mining in Nigeria has left behind, abandoned and un-reclaimed mine sites, to the detriment of the surrounding communities, the environment and biodiversity. 

 

1.2.3.5 Unsustainable Harvesting of Non Timber Forest Products

 

Nigeria’s population is largely rural and agriculture plays an important role in the national economy. Nigerian agriculture affects biodiversity in a number of ways.

Almost all other forest exploitation processes affect the non-timber forest products. These products – nuts, fruits, seeds, ropes, dye, lianes, gum, wax, honey, wild animals etc constitute a huge resource of food, medicine and commerce but unplanned and uncontrolled harvesting due to human pressure has degraded the resource to a less productive level. Most of the expanding local trade in traditional medicine, fibres and domestic material needs are not domesticating the much needed raw materials; they are however continuously being sourced from the wild, thereby reducing population density of the species and causing near extinction of many species.

 

1.2.3.6 Pollution

 

The production and use of toxic chemicals pose a major and relatively new threat to humankind and the environment. Emissions from vehicles, industrial processes, liquid and solid waste, pesticides and chemical fertilizers for agricultural and domestic purposes release toxic substances into the air, soil or water thereby affecting aquatic and other organisms in the environment. Heavy metals and persistent organic pollutants such as polychlorinated biphenyls, dioxins and DDT are of particular concern since they do not degrade easily in the environment. They accumulate and are lethal to plants, animals, fishes and human beings resulting disruption in the ecosystem loss of species.

 

Fig.5.A Polluted water body. Source: NCF

Pollution has become one of the most serious problems of our time and water pollution is one of the prime reasons for the loss of aquatic genetic diversity. This view is further confirmed by the UNEP (2011) report that concludes that pollution of soil by petroleum hydrocarbons in Ogoni-land is extensive in land areas, sediments and swampland. Most of the contamination is from crude oil although contamination by refined product was also found at three locations. Oil pollution in many intertidal creeks has therefore left mangroves denuded of leaves and stems, leaving roots coated in a bitumen-like substance sometimes 1 cm or more thick. Mangroves are spawning areas for fish and nurseries for juvenile fish and the extensive pollution of these areas is impacting on the fish life-cycle. With oil spill on land, fires often break out, killing vegetation and creating a crust over the land, making remediation or re-vegetation difficult.

 

The report also observed that if the noticed increase in artisanal refining in parts of the Niger Delta region is left unchecked, it may lead to irreversible loss of mangrove habitats in this area. It was reported that between 2007 and 2011, artisanal refining has been accompanied by a 10% loss of healthy mangrove cover, or about 307, 381 m2. The UNEP investigation also found that the surface water throughout the creeks contains hydrocarbons, with floating layers of oil varying from thick black oil to thin sheets.

 

 

 

1.2.3.7 Gas Flaring

 

Due to the lack of gas utilization infrastructure, Nigeria flares approximately 75% of the gas it produces and re-injects only about 12% for enhanced oil recovery. Gas flaring contributes to both the production of the acid in acid rain and increased carbon emissions into the atmosphere.

 

One local study (Pollutec 1996) estimated that 12 million tons of methane gas is released into the atmosphere in Rivers and Delta States. It also subjects flowering plants to heat radiation, high temperatures and excessive light and gas deposits (dry and wet depending on the season). In the Niger Delta, Pollutec (1996) also noted that affected plants show signs of chlorosis (leaf discoloration), scorching, browning and desiccation, stunting and death after prolonged exposure. The same study also noted that gas flares attracted yam beetles and grasshoppers that destroy crops.

 

1.2.3.8 Invasive Species

 

Invasive species inhibits ecological processes and reduces the value of the environment, thereby limiting livelihood options available to people living and dependent on such ecosystems. They are also termed as plant invaders, as alien plants that invade and replace native vegetation. Some of the common invasive species in Nigeria are Nypa palm (Nypa fruticans), Water hyacinth (Eichhornia crassipes) and Typha grass (Typha latifolia). Invasive weeds have however impacted negatively on their new area of invasion exerting untold hardship on the people, particularly poor farmers, the biodiversity, including entomofauna and phyto-flora. Most of these weed species smother out the native species into extinction while others produce allellopathic substances that eliminate other species around them (Adebayo & Uyi, 2010).

 

Nypa palm was introduced into Nigeria in 1906 from Singapore Botanic Gardens, to control coastal erosion. It grows up to 10 m tall and produces large buoyant propagates that are dispersed by ocean currents. This invasive species has invaded the Nigerian coastal environment and has displaced the native mangroves of the Niger Delta, causing loss of biodiversity and hardship to coastal communities who depend on the biodiversity and the dynamics of the mangrove ecosystem for their livelihood. The species invades deforested and exposed mudflats and forms dense mono-specific stands that out-compete native mangrove species. The lack of stilt roots, absence of leaf litter and dense structure reduces estuarine habitat and has negatively affected native biodiversity.

Water hyacinth (Eichhornia crassipes),(Mart.) Solms-Lamb (Family Pontederiaceae), is a floating aquatic plant with inflated petioles and native to tropical America (Hutchinson and Dalziel 1968). It is believed that the weed originated from Brazil, but is widely spread all over Southern and Central American countries, having been introduced as an ornamental in the 1890's (Penfound and Earle 1948). It is a major weed in several regions of the world having climatic regions similar to its native habitat. In many countries where it is a pernicious weed, it has been found to interfere with river transportation, irrigation channels, pumps and access to water by riverine communities and recreational activities. 

 

Water hyacinth has become a major weed in Nigeria having successfully invaded and established itself on the entire Badagry Creek, the Yewa Lagoon, Ologe Lagoon, the Lagos Lagoon and the waterways of the riverine areas of Okitipupa. It was reported in 1982 in the local newspapers as a weed that is spreading fast and paralyzing the fishing industry. Since this initial report, the surge in growth has become phenomenal leading to complete coverage of some of these creeks and lagoons. As a result of this invasion, Akinyemiju (1987) gave a rough estimate that more than one third of Nigeria’s local fish supply has become threatened by the mats of water hyacinth. It is known in Nigeria for example that the salinity of the Lagos Lagoon usually drops drastically during the raining season thereby enhancing a build-up of the weeds during this season. The conducive temperatures and high rate of reproduction coupled with the seasonally low salinity of the Lagos lagoon made the water hyacinth an especially dangerous threat to the continued use of the affected Nigerian waters as a resource, unless appropriate and effective control is adopted and implemented forthwith.

 

The Federal Government of Nigeria has made attempts to maintain focus on the control of invasive species, most particularly water hyacynth in recent times and Nypa Palm in the recent past. Apart from data and information sharing, there is need for much more investments in research, stakeholder participation in the control of invasive species and seeking opportunities for converting waste to wealth approach to management.

 

Typha grass (Typha latifolia) is a native plant species of North and South America, Europe, Eurasia, and Africa. T. Latifolia generally grows in flooded areas where the water depth does not exceed 0.8m. However, it has also been reported growing in floating mats in slightly deeper waters. Typha is often among the first wetland plants to colonize areas of newly exposed wet mud, with its abundant wind dispersed seeds. The buried seeds can also survive in the soil for long periods. It germinates best with sunlight and fluctuating temperatures, which is typical of many wetland plants that regenerate on mud flats. It also spreads by rhizomes, forming large interconnected stands. Hence, it has three interlocking reproductive strategies: dominance of local habitats by clone growth, survival of long inhospitable periods with buried seeds, and dispersal to new sites with wind-dispersed seeds. 

This may explain in part why the species is so widespread. It is considered to be a dominant competitor in wetlands, and often excludes other plants with its dense canopy. Although this is a natural species of wetlands, there is growing concern about the degree to which it is replacing other native species. 

 

Today, it is a native invasive plant species devastating the watersheds of the Chad Basin and Hadejia-Nguru wetlands, causing flooding, loss of farmlands and conflict among farmers, herdsmen and fishermen. NCF/WOW (2011) reported that Typha weed has colonized areas of the wetland, blocking channels and open water, and preventing water reaching some seasonal pools, so that farming has ceased in these areas, while flooding has displaced many communities. 

 

In an effort to reduce the extent of typha in the area, NCF/WOW and other supporting organizations, assisted the communities of DabarMagini, Kasaga and Matafari/MataraUku, to physically clear typha that blocked and hindered free movement of water in the Marma channel, a key freshwater channel that serves as the lifeblood to the people living in these locations.

 

 

 

1.2.3.9 Overgrazing

 

Overgrazing occurs when plant material is grazed faster than it can naturally regenerate, often leading to the permanent loss of plant cover. It is a common effect of too many animals grazing on limited range land and also occurs when plants are exposed to livestock grazing for extended periods of time without sufficient recovery periods. It reduces the usefulness of the land and is one of the causes of soil erosion and desertification. Overgrazing can occur under continuous or rotational grazing. It can be caused by having too many animals on the pasture land or by not properly controlling their grazing cycle. Overgrazing reduces plant leaf areas, which prevents sunlight from reaching the plant and affects the plant growth. Plants become weakened and have reduced root length.

 

The area devoted to grazing in Nigeria rose from 166, 326 km2 in 1978, to 187, 236km2 in 1995. Because most of the cattle are concentrated in the semi-arid zones that support 90% of cattle, the area is subjected to overgrazing and shortage of fodder. 

 

EPI (2011) reported that one indicator that helps in the assessment of grassland health is changes in the goat population relative to those of sheep and cattle. As grasslands deteriorate, grass is replaced by desert shrubs. In such a degraded environment, cattle and sheep do not fare well but goats, being particularly hardy ruminants, are able to forage on these desert shrubs.

Nigeria, Africa’s most populous country, reports losing 867, 000 Ha of range land and crop land to desertification each year (EPI, 2011). As human and livestock populations increase, herders and farmers compete for the limited land for farming and grazing. The goat population in particular has skyrocketed as the soil has eroded. If Nigeria’s human and livestock population continues to grow as they are today, the associated land degradation will eventually undermine the nation’s capacity for farming and livestock production.

 

The Federal Government’s concern over this threat has resulted in the introduction of a draft bill to the National Assembly for an Act establishing a National Grazing Reserves Commission; with powers to acquire and develop land for grazing and livestock routes in any part of the country. This bill, which is highly controversial, is yet to be passed by the National Assembly.

 

1.2.3.10 Bush fires

 

Bushfires occur widely and extensively and have become common occurrence in the Nigerian environment. Fire is widely accepted throughout the country as a valuable tool for the management of natural vegetation, agriculture, including livestock production, hunting and in other land use systems. Bush fires occur when they are ignited by farmers during the dry season in the process of land clearance/preparation for farming. If not contained, they may spread and cause damage to vegetation, other farmlands, gardens and even residential areas.

 

Others may be deliberately set by hunters to flush game, or by livestock herdsmen to stimulate fresh grass. Accidental bushfires are also known to have started by improperly discarded cigarettes by smokers. Although fire can be deployed as a management tool to suppress the development of thickets and control ticks and other parasites in protected area, their devastating effect, if not properly controlled and suppressed, can cause the loss of native flora and fauna that may take several years to regenerate.

 

Fire also creates negative impacts on the composition and density of vegetation and delays the attainment of sustainable development targets and also accelerates desertification and general environmental degradation. Small mammals, ground-nesting birds, soil-dwelling organisms and numerous invertebrate species are often victims of wildfires. In forest ecosystems, wildfires repress seedling establishment in some species and create wounds on some big plants through which they become infected by disease agents. Fire destroys large areas of forest ecosystems annually with the elimination of sensitive species such as Afromosia laxiflora), Silk Cotton tree (Ceiba pentandra), Entanda abyssinica and Hildegardia barteri