Regime Shifts DataBase

Large persistent changes in ecosystem services

Productive Land Use Regime

The productive land use regime in Maradi Region as well as in the rest of Niger consists of a landscape characterised by sparse rural populations cultivating small fields amidst surrounding bush. Population densities are smaller with sufficient yields and ample supplies of timber and other forest products from natural woodlands. Fallow practices are common allowing fields to rest, and trees and shrubs are regenerated to provide extra wood before being cleared for planting (Winterbottom 2008). The most important feature of this regime is the fallow time which allows the environment to keep its natural productive capacity intact and provide a host of services such as soil and water conservation, increased soil fertility and goods among which food crops and fuel-wood in abundance. More importantly is that that productive period coincided with the wet decades that spanned from 1900 through with higher rainfalls during the 1920s, 1930s and 1950 (Hulme 2001).

Desert Regime 

The desert regime traces back to early 1960s, punctuated by the increasingly episode that commenced in the Sahel in the late 1960s, and which culminated in severe droughts in 1973, 1984 and 1990 (Warren 1995), and continues today. It is generally depicted as a regime characterised by an ongoing depreciation in ecosystem services and goods and moving towards a desert ecosystem. The landscapes are dominated by vast expanses of savannah devoid of vegetation under desertification threats until the early 1980s. This has resulted from a series of practices as a consequences of the enactment of institutional arrangements and enforced by both the French colonial government as well as the successive post-colonial governments. This regime regime illustrates high degrees of erosion and decreased soil fertility which has resulted in poverty and destitution translated into hunger, malnutrition, imbalanced diets and sometimes massive death.

Land clearing and tree-felling became common in the 1930s as the colonial administration pushed Nigerien farmers to grow export crops (cotton) and implemented policies that provided disincentives for farmers to care for their land (World Resources report 2008). Such disincentives included a new land law that established the national government as the owner of all trees and required Nigeriens to purchase permits to use them (Brough & Kimenyi 2002). By clearing native trees and shrubs, farmers exposed their lands to the fierce Sahara winds, resulting in plummeting soil fertility and harvests as a result of increased erosion. The loss of tree cover also triggered a rural fuel-wood crisis. Poor households were forced to burn animal dung or crop residues instead of using them for compost, reinforcing the downward spiral in soil quality and crop yields declines (Rinaudo 2007; Winterbottom 2008). Incidentally that resulted in an increase in intensity of cultivation of land reducing thus the fallow time to keep up with the production levels needed to feed an increasing human population which made it that woodlands were to be converted into farmland. That, in turn, contributed to land clearing and tree-felling and the cycle repeated itself in a reinforcing feedback loop.

The shrinking of Niger’s natural tree cover was exacerbated by a rapid population growth. That was a result of the perversely positive outcomes of the effective French health care system, notably higher life expectancy and lower infant mortality which incidentally increased a strain on natural resources (Brough & Kimenyi 2002). Therefore by 1975 much of the remaining natural woodland had been converted to farm fields to feed rapidly growing rural communities increasing consequently intensity of land cultivation which, in turn, reduces yield per hectare making food production one of recurrent problem for food security. As a result, the practice of fallow was abandoned altogether. By 2015, the Niger’s population will rise to 18.8 million and the area of cultivable land per capita will fall further- from 1.45 to 1.12 ha per person (Wentling 2008). But by clearing native trees and shrubs, farmers exposed their fields to the fierce winds, resulting in plummeting soil fertility and thereby harvests. In addition to the damaging effects of Sahara winds, the latter destroyed seeds in Niger’s June-to-October growing season that resulted more often in repeating sowing, destroying newly planted crops. The third and last driver is a series of an extreme 4-year drought that triggered famine across the Sahel in general through yield failures by impairing moisture in crop root zone, afflicting 50 million of people (Dan Baria 1999). Over the last 45 years, Niger has been plagued by an average of one bad harvest every eight years, following a growing season of low rainfall (Wentling 2008). That has exposed farmers to deadly cyclical droughts, which are predicted to increase as a result of climate change (Reij 2006; IPCC, 2007). These frequents droughts henceforth have increased rainfall variability that jeopardise bio-productivity of the system under study.

The shift from a productive land use to a desert regime has direct impact on biodiversity of the area, causes soil erosion and decreases productivity therefore affecting provisioning services such as fuel-wood, and food for the local communities.

This has a direct impact on human wellbeing as it has increased poverty, hunger, malnutrition, imbalanced diets and sometimes even death.

Much of hope that has reversed desertification has come from the transformation of vast expanses of savannah devoid of vegetation into relatively densely studded landscapes with trees, shrubs, and crops. That has been achieved through an unprecedented, farmer-led re-greening movement initiated by the Maradi Integrated Development Project (MIDP) featuring a new approach to reforestation (Rinaudo 2005). This approach consists of low-cost techniques for managing the natural regeneration of trees and shrubs, known as farmer-managed natural regeneration, or FMNR. These techniques involved supporting the regeneration of trees and their sustainable management to produce continuous supplies of fuel-wood as well as non-timber products such as edible seeds and leaves. MIDP’s effort entailed few rules emphasizing farmer experimentation and choice. In fact, farmers chose how many trees stumps to let re-sprout in their fields, how many re-sprouted stems to grow and harvest, and what to do with the wood (Rinaudo 2005). By planting alternate rows of neem (Azadirachta indica) -an exotic nursery-grown species –and a native Acasia nilotica saplings across the valley to act as windbreaks, this techniques improved soil retention and fertility (Steinberg 1988). Re-vegetation also improves the traditional poor fertility of Niger’s soils, which in turn boosts crop production. Bush trees dotted across fields help hold soil in place, reducing wind and water erosion (Guero & Dan Lamso 2006). Moreover, the growing season on land with trees is longer because farmers only have to sow once, compared with twice or more on fields unprotected from the elements (Rinaudo 2005; Reij 2008). Such benefits are magnified when farmers act collectively. Vegetation in one field affects nearby land by serving as a windbreak and promoting improved water infiltration and soil retention (Winterbottom 2007). Besides the FMNR much of the success of the re-greening movement can also be attributed to the simultaneous soil and conservation work. In fact, simple soil and water conservation techniques were used to rehabilitate barren land. These widely adopted techniques consist of rock lining, improved versions of traditional planting pits or tasa, and demi-lunes that improve water infiltration into soil thereby increasing moisture in the root zone (Abdoulaye and Ibro, 2006). These techniques enabled cultivation of secondary vegetable crops such as onions, tomatoes, sweet potatoes, cow peas, watermelon, and asparagus for home use and sale in local markets (Guero & Dan Lamso 2006). This simple and cost-effective practice of farmer-managed natural regeneration has provided an impressively wide range of benefits for Niger’s impoverish rural communities. Over the last 30 years or so, about 200 million trees have been protected and managed by farmers in the FMNR regions and at least 250,000 ha of degraded land has been restored to crop production (Reij 2008; McGahuey & Winterbottom; 2007). On the other hand, there has been a perceptible trend in the increase in rainfall that has recently been noticed across the Sahel region as a whole that might also account for that change that is happening.

Productive Land Use Regime

The productive land use regime in Maradi Region as well as in the rest of Niger consists of a landscape characterised by sparse rural populations cultivating small fields amidst surrounding bush. Population densities are smaller with sufficient yields and ample supplies of timber and other forest products from natural woodlands. Fallow practices are common allowing fields to rest, and trees and shrubs are regenerated to provide extra wood before being cleared for planting (Winterbottom 2008). The most important feature of this regime is the fallow time which allows the environment to keep its natural productive capacity intact and provide a host of services such as soil and water conservation, increased soil fertility and goods among which food crops and fuel-wood in abundance. More importantly is that that productive period coincided with the wet decades that spanned from 1900 through with higher rainfalls during the 1920s, 1930s and 1950 (Hulme 2001).

Desert Regime 

The desert regime traces back to early 1960s, punctuated by the increasingly episode that commenced in the Sahel in the late 1960s, and which culminated in severe droughts in 1973, 1984 and 1990 (Warren 1995), and continues today. It is generally depicted as a regime characterised by an ongoing depreciation in ecosystem services and goods and moving towards a desert ecosystem. The landscapes are dominated by vast expanses of savannah devoid of vegetation under desertification threats until the early 1980s. This has resulted from a series of practices as a consequences of the enactment of institutional arrangements and enforced by both the French colonial government as well as the successive post-colonial governments. This regime regime illustrates high degrees of erosion and decreased soil fertility which has resulted in poverty and destitution translated into hunger, malnutrition, imbalanced diets and sometimes massive death.

Land clearing and tree-felling became common in the 1930s as the colonial administration pushed Nigerien farmers to grow export crops (cotton) and implemented policies that provided disincentives for farmers to care for their land (World Resources report 2008). Such disincentives included a new land law that established the national government as the owner of all trees and required Nigeriens to purchase permits to use them (Brough & Kimenyi 2002). By clearing native trees and shrubs, farmers exposed their lands to the fierce Sahara winds, resulting in plummeting soil fertility and harvests as a result of increased erosion. The loss of tree cover also triggered a rural fuel-wood crisis. Poor households were forced to burn animal dung or crop residues instead of using them for compost, reinforcing the downward spiral in soil quality and crop yields declines (Rinaudo 2007; Winterbottom 2008). Incidentally that resulted in an increase in intensity of cultivation of land reducing thus the fallow time to keep up with the production levels needed to feed an increasing human population which made it that woodlands were to be converted into farmland. That, in turn, contributed to land clearing and tree-felling and the cycle repeated itself in a reinforcing feedback loop.

The shrinking of Niger’s natural tree cover was exacerbated by a rapid population growth. That was a result of the perversely positive outcomes of the effective French health care system, notably higher life expectancy and lower infant mortality which incidentally increased a strain on natural resources (Brough & Kimenyi 2002). Therefore by 1975 much of the remaining natural woodland had been converted to farm fields to feed rapidly growing rural communities increasing consequently intensity of land cultivation which, in turn, reduces yield per hectare making food production one of recurrent problem for food security. As a result, the practice of fallow was abandoned altogether. By 2015, the Niger’s population will rise to 18.8 million and the area of cultivable land per capita will fall further- from 1.45 to 1.12 ha per person (Wentling 2008). But by clearing native trees and shrubs, farmers exposed their fields to the fierce winds, resulting in plummeting soil fertility and thereby harvests. In addition to the damaging effects of Sahara winds, the latter destroyed seeds in Niger’s June-to-October growing season that resulted more often in repeating sowing, destroying newly planted crops. The third and last driver is a series of an extreme 4-year drought that triggered famine across the Sahel in general through yield failures by impairing moisture in crop root zone, afflicting 50 million of people (Dan Baria 1999). Over the last 45 years, Niger has been plagued by an average of one bad harvest every eight years, following a growing season of low rainfall (Wentling 2008). That has exposed farmers to deadly cyclical droughts, which are predicted to increase as a result of climate change (Reij 2006; IPCC, 2007). These frequents droughts henceforth have increased rainfall variability that jeopardise bio-productivity of the system under study.

The shift from a productive land use to a desert regime has direct impact on biodiversity of the area, causes soil erosion and decreases productivity therefore affecting provisioning services such as fuel-wood, and food for the local communities.

This has a direct impact on human wellbeing as it has increased poverty, hunger, malnutrition, imbalanced diets and sometimes even death.

Much of hope that has reversed desertification has come from the transformation of vast expanses of savannah devoid of vegetation into relatively densely studded landscapes with trees, shrubs, and crops. That has been achieved through an unprecedented, farmer-led re-greening movement initiated by the Maradi Integrated Development Project (MIDP) featuring a new approach to reforestation (Rinaudo 2005). This approach consists of low-cost techniques for managing the natural regeneration of trees and shrubs, known as farmer-managed natural regeneration, or FMNR. These techniques involved supporting the regeneration of trees and their sustainable management to produce continuous supplies of fuel-wood as well as non-timber products such as edible seeds and leaves. MIDP’s effort entailed few rules emphasizing farmer experimentation and choice. In fact, farmers chose how many trees stumps to let re-sprout in their fields, how many re-sprouted stems to grow and harvest, and what to do with the wood (Rinaudo 2005). By planting alternate rows of neem (Azadirachta indica) -an exotic nursery-grown species –and a native Acasia nilotica saplings across the valley to act as windbreaks, this techniques improved soil retention and fertility (Steinberg 1988). Re-vegetation also improves the traditional poor fertility of Niger’s soils, which in turn boosts crop production. Bush trees dotted across fields help hold soil in place, reducing wind and water erosion (Guero & Dan Lamso 2006). Moreover, the growing season on land with trees is longer because farmers only have to sow once, compared with twice or more on fields unprotected from the elements (Rinaudo 2005; Reij 2008). Such benefits are magnified when farmers act collectively. Vegetation in one field affects nearby land by serving as a windbreak and promoting improved water infiltration and soil retention (Winterbottom 2007). Besides the FMNR much of the success of the re-greening movement can also be attributed to the simultaneous soil and conservation work. In fact, simple soil and water conservation techniques were used to rehabilitate barren land. These widely adopted techniques consist of rock lining, improved versions of traditional planting pits or tasa, and demi-lunes that improve water infiltration into soil thereby increasing moisture in the root zone (Abdoulaye and Ibro, 2006). These techniques enabled cultivation of secondary vegetable crops such as onions, tomatoes, sweet potatoes, cow peas, watermelon, and asparagus for home use and sale in local markets (Guero & Dan Lamso 2006). This simple and cost-effective practice of farmer-managed natural regeneration has provided an impressively wide range of benefits for Niger’s impoverish rural communities. Over the last 30 years or so, about 200 million trees have been protected and managed by farmers in the FMNR regions and at least 250,000 ha of degraded land has been restored to crop production (Reij 2008; McGahuey & Winterbottom; 2007). On the other hand, there has been a perceptible trend in the increase in rainfall that has recently been noticed across the Sahel region as a whole that might also account for that change that is happening.

The shift from oligotrophic to eutrophic conditions occurs when a body of water – a lake, river or reservoir – accumulates excessive nutrients. This process can happen naturally over several centuries as a lake ages and accumulates sediments and nutrients from the surrounding landscape. Alternatively, human activities, especially the use of fertilizers, causes freshwater eutrophication to occur much more rapidly and extensively than in the past.

Low Nutrient Clear water/Oligotrophic

In the clear water regime, phosphorous inputs, phytoplankton biomass (algae), and phosphorous recycling from lake or river sediments are typically low, and the water is clear. Such systems are called oligotrophic. Oligotrophic lakes are associated with the provision of services such as freshwater, fisheries and food for wild animals. It is also related with pest and disease regulation as well as water purification. Clear water lakes are also used for recreation and their aesthetic values.

High Nutrient Turbid Water/Eutrophic

In the eutrophic regime, phosphorous inputs, phytoplankton biomass, and phosphorous recycling from sediments are usually high, and the water is turbid or murky. Such systems are called eutrophic or nutrient rich (Carpenter 2003, Smith and Schindler 2009).

Eutrophic lakes have significant impacts on fisheries, both commercial and recreational. Murky water and unpleasant odors cause loss of aesthetic value. Toxin produced by algae may affect livestock, mussels, oyster and even humans when water is used for drinking (Lawton and Codd 1991).

The main causes of lake eutrophication is excess nutrients inputs, especially phosphorous. Over enrichment of phosphorous often leads to algae blooms which changes both the trophic structure of the lake and the chemical environment. Consequences include depletion of oxygen in the water and increase in water turbidity, creating harsh conditions for fish and plants to survive.

Nutrient inputs are driven by the use of fertilizers in agriculture. Therefore, indirect drivers such as food demand and population growth exacerbate the problem. Rainfall variability also plays a synergistic role with land use change, allowing further erosion of soils and leaking of the nutrients not used by crops. Urban growth often increases the flux of nutrients by changing the landscape surface by one less permeable, increasing leakage and sewage production.  Untreated sewage is often a major cause of eutrophication near cities or towns.

Clear water or oligotrophic freshwater occur when nutrient inputs are low and nutrient concentrations are maintained at low levels by flora and fauna of the lake. The vegetation, for example, consumes phosphorous from the water column, and its roots immobilize phosphorous in the lake sediments by stabilizing the sediments. Phosphorous is also trapped in sediment or in inorganic forms, biologically unavailable for small algae.

Increasing nutrients input can overwhelm the capacity of plants to control phosphorous levels both by consumption and immobilization in sediment.  The ability of a freshwater ecosystem to regulate nutrients depends upon a number of ecological and geographic factors.  Ecological factors include the structure of the food web (the amount of predation on algae), the presence of vegetation (which shades or stabilizes the sediment), and the presence of sediment disturbing biota (which mobilizes nutrients).  While geographic factors include degree to which the lake is mixed by wind, temperature, and depth.  Increased mixing and temperature can decrease the resilience of the clear water regime by encouraging algae growth.

A lake can be maintained in a eutrophic or high nutrient regime, by changes in the food web that favour algae, continuation of sediment disturbance, or the mobilization of stored phosphorus due to chemical recycling due to low oxygen conditions in the sediment.

Shift from Oligotrophic to Eutrophic lake

Eutrophication induces large changes in ecological communities and hence the configuration of food webs. Primary producers (algae) experience massive population increases, while fish and shellfish may suffer large population declines due to lack of oxygen. Consequently less energy is captured by higher trophic levels, and more by the lower trophic levels. Rooted aquatic plants tend to be lost due to shading by algae. The loss of macrophytes has cascading effects on zooplankton and other organisms that depend on these plants for habitat and food (Carpenter  2003).  These food web changes are accompanied by changes in the phosphorous and carbon cycles of the affected ecosystems: larger quantities of phosphorous and carbon are cycled through the ecosystem at higher rates. In addition, large swings in the amount of dissolved oxygen in the water may take place (Carpenter 2003).

Changes in the ecological communities resulting from eutrophication can make a system more vulnerable to invasion by new species or to disease outbreaks. Nutrient-rich waters are a good environment for the development of pathogens like cholera (Smith and Schindler 2009). Some algal blooms produce toxic compounds, such as neurotoxins, that can move up the food chain resulting in illness or death when consumed by animals or humans (Lawton and Codd 1991).

Eutrophication has several direct consequences for human well-being (Carpenter et al. 1998, Postel and Carpenter 1998):

• Loss of fish species from eutrophic ecosystems impact commercial, subsistence, and recreational fishing;


• Recreational use of water bodies for swimming, boating and angling are reduced,


• The value of lakeside properties and recreational areas are reduced due to unpleasant odours and murky water,


• The costs of water treatment for domestic, industrial and agricultural uses increases,


• Toxins produced by certain algal blooms may cause death of livestock (and humans) if eutrophic water is used for drinking,


• Biotoxins produced by algae may be taken up by shellfish such as mussels and oysters, and can lead to the poisoning of humans when consumed (Lawton and Codd 1991).

Shift from eutrophic to oligotrophic lake

The degree of reversibility from eutrophic to oligotrophic conditions varies greatly. In some lakes oligotrophic conditions have been restored rapidly after reduction of phosphorous inputs, while in other cases lakes have remained eutrophic despite prolonged reductions in phosphorous inputs and even dredging of the lake sediments (Carpenter et al. 1999, Carpenter 2003).

Ecosystem services may recover once the system shift back to oligotrophic regime. However, some species may never come back to initial abundance and the food web may change drastically. Consequently, the impact of eutrophication on fisheries depends upon the species being fished. Other services related with aesthetic and recreational values including tourism can fully recover.

Options for enhancing resilience

Freshwater ecosystems react in different ways to increases and reductions in nutrient loading, depending on their shape, water current patterns, and biological characteristics. Different strategies for managing eutrophication will therefore be required in different settings (Smith 2003).

The main management option, both for prevention and restoration, is to reduce phosphorous inputs. Developing technology and economic incentives to close the nutrient cycle at the local (farm) level is crucial (Diaz and Rosenberg 2008). Reforestation of watersheds can help buffer the impact of rainstorms on soil erosion and phosphorous runoff. Importantly, phosphorous sources tend to be concentrated spatially in the landscape. Reducing runoff from a small number of high source areas can have a major impact on water quality, and should be a priority.

Options for reducing resilience to encourage restoration or transformation

Active intervention may be needed to reverse eutrophic conditions. For instance, lake floor sediments can be dredged, or phosphorus can be immobilized by adding aluminium sulphate (Carpenter 2003). Bottom-feeding fish such as carp, which physically stir up lake-floor sediments when feeding, can also be removed.

Another option for managing eutrophication is through "biomanipulation" of food webs (Scheffer 1997). This involves increasing the population of predatory fish such as bass, pike and walleye through stocking or reduced angling quotas. Increased populations of these predators leads to a decrease in the level of zooplanktivores. This in turn allows an increase in the population of planktivores that graze on the algae, helping to reduce the algal density. Results from biomanipulation studies have given rise to the idea that, to reduce eutrophication, lakes should be managed to contain an even, rather than odd, number of trophic levels (Smith and Schindler 2009).