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ITS 2006

RESPONSE OF BIODIVERSITY TO RADIAL DISTANCES FROMTRADITIONAL WELLS IN HAOUSSA, MALI.

SEYDOU FONGORO

RESPONSE OF BIODIVERSITY TO RADIAL DISTANCES FROM

TRADITIONAL WELLS IN HAOUSSA, MALI

BY

SEYDOU FONGORO

NORWEGIAN UNIVERTY OF LIFE SCIENCE

NORAGRIC-DEPARTMENT OF INTERNATIONAL ENVIRONMENT AND

DEVELOPMENT STUDIES

MAY 2006

Chapter 1

1.0 Introduction

Provision of water for livestock is a necessary requirement for pastoral land use

in the dry parts of West Africa. Around the well clusters annual grasses dominate the

vegetation, especially during the wet season (James, al. 1999) but remain bare during the

dry season. In the piosphere created around individual wells might have contributed to

changes in the composition of the herbaceous vegetation (Thrash, 1993). The reasons are

because well points promote heavy trampling and grazing (Van Rooyen et al.1990;

Hanan et al .1991; Thomas et al.2000), causing overgrazing (Lange 1969; Jeltsch et

al.1997). The effects are profound and important aspect of change in arid and semi-arid

rangelands that has been associated with desertification (Hiernaux,1992), The cumulative

effects of livestock grazing and trampling are suggested to introduce changes in plant

species composition (Thrash, 2000) and to lead in reduction of plant species richness,

plant cover and biomass; shifts in palatable plants have clearly been affected and

widespread increase in grazing pressure (James et al. 1995a; Landsberg et al. 1996). The

use of different wells of different ages might reveal the extent of impact (Fleischhauer;

Bayer & Lossau, 1998). The impacts of wells on the grazing lands could not however be

understood without analyzing the traditional systems of water management in the semi-

desert region that probably have inbuilt systems that reduce the consequence for the

environment.

The livestock grazing intensity gradient associated with artificial watering points has

effects on both vegetation and the physical environment. Impacts on the physical

environment include changes to soil nutrient levels (Tolsma et al. 1987). The effects on

vegetation, increased shrubs mortality and defoliation (Andrew & Lange 1986), changes

in herbaceous vegetation (Thrash, 1998) and increase invasive species (Brooks et al.

2006). Perennial plant cover increased rapidly away from watering points (Todd, 2006).

Some studies showed no consistent relationship between herbaceous species diversity and

distance from water points (Thrash et al. 1993). In Oshana ecosystem in Namibia, radial

distance had significant effects on herbaceous species richness and age of water points

1

played an influential role (Nangula & Oba, 2004). Other studies showed that grass

species richness increased with distance (e.g., Todd, 2006).

In the semi-desert region, bordering the Sahara, pastoral nomads including Arabs

and Touareg for several centuries have been able to exploit the harsh environment by

sinking deep hand dug wells that provided sources of water and allowed pastoralists

expansion further north and east in the Azouad and Adrar regions (Marie, 1977). The

region was utilized for wet season grazing using surface rainfall waters in the wadis and

pans. However, beginning about the mid-sixteenth century the Arab nomads and the

Touaregs of the haoussa region dug deep wells (Deyoko, 2005). The distributions of the

wells along the migratory routes opened up areas of grazing that were previously

inaccessible. In other areas, grazing and camping by pastoral families were for longer

periods and could have set into process vegetation change from the pre-water

development periods. However, uptill this day, we lack sufficient scientific information

about the impacts of traditional wells on rangeland biodiversity, despite the water points

being blamed for initiating processes of desertification, particularly in the region that

borders the Sahara desert (Fleischhauer; Bayer & Lossau, 1998).

The traditional wells vary in depth within the radius of 70 to 130 meters. The

water is brought to the surface through use of systems of pulleys operated by traction

animals creating heavy livestock trampling of the ground 70-200 m from the wells. The

traditional spacing of wells appears to be changing. Presently, well densities have

increased. Previously, well sites had few well clusters but the clusters are increasing. In

our study area, for example, there were more than 35 functional wells within 489-km2.

The inter-well distances varied from a minimum of 200 m to several kilometers. The

nomadic communities are aware that the spacing and distributions of wells is important

for avoiding overuse of the range. Indeed, there is a strong social control over the

numbers of wells to be sunk in any area. The local residents who have full control over

access to water through delimitations of well ownership establish claims over grazing

lands which others wouldn’t be able to use without being granted rights of access.

This study conducted in Novemeber/December 2005 had the following objectives.

(1) To describe wells ownership and management, (2) To assess the effects of the radial

distances from traditional wells on plant cover, species richness. (3) To assess effects of

2

grazing pressure on plant cover and species richness and (4) relate age of wells as

predictors of plant cover and species richness.

3

Chapter 2 2.0. Study area and methods 2.1. Study area

The study was conducted in the commune of Bamba located in the northern part of

Mali between 1° 06 and 1° 35 longitude West, 16°59 and 17°51 latitude North (Fig.1).

The region lies at the edge of the Niger River, covers approximately 4776 km2. Rainfall

is highly variable between years (Fig.2). Average annual rainfall is rarely more than 150

mm, 95% of the rainfall expected between August and October. The rainy period is from

July to October. The year 2005 when the present research was conducted received the

heaviest rainfall of 223.2 mm (Meteorological Department, Mali, personal comm.2005).

Generally, the region has minimum temperature of between 15° C and 30° C from

December to January and the maximum between 30°C and 45°C from May to June.

Ecologists describe rainfall in northern Mali as extremely variable (de Leeuw, Diarra &

Hiernaux, 1993). Consequently, annual precipitation is a poor indicator of biomass

production because of spatial and temporal rainy variability (Bernus, 1974:14-15).

“Useful rainfalls” is a shower of 3 mm or more, followed by a similar shower after an

interval of one week (Gallais, 1967:220). The first rain in mid June sufficiently provides

moisture to allow grass germination and promote plant growth.

The main landscapes are composed of active and stabilized sand dunes. Sand

dunes movements have been used as evidence of desertification in the Bamba commune.

The soil type is sub desert with thin layer. The vegetation is mostly composed of Acacia

raddiana, Balanites eagyptiaca and the grass, both perennial, Colocyntthis cittrullus,

Cyperus jeminicus, Panicum turgidum; annuals Aristida mutabilis, Boerhavia repens

Corchorus tridens, Gisekia pharnacioides, Indigofera aegyptiaca, Indigofera

Senegalensis. The ROSELT of Bourem (Observatory Network and Ecological

Monitoring in Long Run, 2003) has classified the haoussa in three zones: the south-

haoussa zone, north haoussa and the edge of Niger River. The southern zone is located

approximately 5 to 30 km to the north of the Niger River. Northern haoussa is located

beyond 30 km in the North of the Niger River; the third zone (the edge of the river) is

located in less than two km of the Niger River.The three zones vary in their range

productivities as illustrated by the productivity measurments taken by Regional Center of

4

Agronomic Research of Gao in 2002 which for the southern zone varied from 38-947 kg

ha-1, for northern zone of 107-788 kg ha-1 and no production at the edge of the river

(Regional Center of Agronomic Research, 2002).

Fig1. Location of study area within Mali

5

m

m)

all (

rain

0

50

100

150

200

250

1971

1973

1975

1977

1979

1981

1983

1985

1990-94 20

002005

years

f

Fig2. Rainfall variability in Haoussa region in years

Pastoralism is the main economic activity in the northern Bamba (Haoussa) where mixed

herds of sheep, goats, camels, donkey, and cattle are managed. The inhabitants are

Touaregs, Arabs, Bellah, Songhay, Fulani, and Bambara. The traditional systems of land

use by the nomads in the Houssa region for several centuries has been an established

practice of transhumance between the wet season grazing areas that took them across

international borders or deeper into the Sahara Desert borders, as rainfall shifts

northwards and southwards. The Gourma on right bank of the Niger River and the

Haoussa on left bank are important transhumance routes for the migratory herds. During

the wet season which lasts three to four months the nomads exploit pasture growth and

surface water. As the surface water dries up, the nomads move back to their dry season

well where they remain until the next rainy season. The southbound migration during the

dry season, take individual herding families to their traditional wells.

From the well site camps on daily basis pastoral families travel between water

points to where fodder is available. As strategy of pasture exploitation, camps have to be

moved several times. As Fig.3 shows, between mid June and November few animals are

dependent on the wells but greater numbers are watered between March and May

suggesting that the wells are used throughout the year. There is no regulation on how

closer to the well a camp is permitted. For the safety of women and children a family may

6

prefer to camp a bit far from well, others may camp far to allow the younger animals who

need to graze at night in the vicinity of the camp. Still others may camp closer to wells

for access to water and travel to pasture area in the remaining time of the day; while other

herders may camp far from traditional wells for access to pasture then prefer traveling

long distances to the wells. Small livestock have very limited ability to travel long

distances with maximum 13 km a day from wells on average. As dry season progresses,

distance between water-sources and pasture increases. This might force most nomads to

move for the next water points. The communities camp around the traditional wells to

exploit pastures. They move their camps depending on pasture availability.

Fig3. Livestock movement around Traditional well in time. The concentrated dots

indicate periods of greater dependence on the wells

7

Fig4. Traditional wells distribution in the Haoussa region.

8

Table1. Description of Traditional Wells Wells Location Description Inamankor 17˚10’34’’ North 01˚25’17’’ West. Watering system is by animal tractions, 45 years old, circumference about 3.45m, used throughout the year Clanssar 17˚19’56’’ North 01˚30’46’’ West Watering system is by animal tractions, 80 years old, circumference about 5.62m, used throughout the year Tabahockomat 17˚03’34’’ North 01˚22’93’’ West Watering system is by animal tractions, 3 years old, circumference about 6.28m, used throughout the year Tamayort 17˚11’37’’North 01˚20’82’’ West Watering system is by animal tractions, 150years old, circumference about 6.28m, used throughout the year Tintates 17˚16’81’’North 01˚19’74’’ West Watering system is by animal tractions, 350 years old, circumference about 9.42m, used throughout the year Sidi mousse 17˚10’96’’North 01˚15’05’’West Watering system is by animal tractions, 60 years old, circumference about 6.28m, used throughout the year 2.2. Field methods

Based on the distance of 35 km in the north from the Niger River, all wells

currently utilized for the study are listed. The selected wells were all located in the north,

on the left bank of the Niger River; covering 489 km2 of the southern zone of Haoussa,

the distributions of the wells are shown in Figure 4. The ages of the wells varied from 3

years to 350 years (Table 1). The minimum distance between wells was 5 km. Key

informants from each fraction (six fractions) were used. I worked with a man who spoke

Arabic, Tamashek and French. A total of six key persons were interviewed to understand:

(i) well ownership systems, (ii) rules used for the use of water of wells and (iii) how the

water was lifted from wells (iv) as well as understanding the age of wells.

9

Between November and December 2005, for the selected wells, the field team

located two 1.4 km transects radiating from each well in opposite compass directions

(Fig5). Because of the heavy trampling around the wells and the piosphere created, all

transects were set at 200 m from the wells. Transects were marked using the GPS (Global

Positioning System) to fix the direction. We then used systematic random sampling

methods to collect the vegetation data (grasses and trees). For grasses (perennial, annual),

we used 1x1 m plots. In each plot ( n = 24 plots) we recorded grazing pressure,

herbaceous cover was estimated, abundance were recorded at 50 m interval between

plots. For shrubs we used 2 x 2 m plots to record the cover, abundance at 100 m of

intervals. We then used 20 x 20 m plots to tree species and cover. In total 12 plots for

trees and shrubs.

West Est. Fig5. Two 1.4km transects around well

Well

2.3. Data analysis

Herder narrative described wells ownership and management. The effects of

radial distances from wells on plant cover, species richness were analyzed using linear

regression and logistic curves fitted. Variations of perennial and annual covers with

different wells were tested using ANOVA. To assess the effects of grazing pressure on

plant cover and species richness, we used linear regression and logistic curve was fitted.

A non-linear regression model was considered to be the best-fit model only when it

explained significantly more of the variation than the linear model. To relate age of wells

as predictors of species richness and plant cover, one-way ANOVA was used.

Statistical analysis were performed on all dependent variables using Minitab software

(2004) version 14.12.0 with significance level fixed at p<0.05.

10

Chapter 3 3. Results

3.1. Wells ownership and management In northern Mali (Haoussa region), wells provide freshwater both for animal and

human consumptions. The wells varied in depth within the radius of 70 to 130 m and

circumference of 3.45 to 9.42 meters. Goat and sheep were watered at the wells daily,

while the watering interval for the camel was three to seven days. Cattle were watered

two to three days intervals. During periods of severe droughts the intervals of watering

were decreased. Traditional wells in Haoussa region were the property of the fractions. A

fraction referred to a territory with spatial delimitation. Wells belonged to individual

families but they were constructed with the resources of the fraction, thereby the

ownership was maintained by individual fractions. The fraction is responsible for wells

management and controlled access to the wells by people from outside the fractions.

Pastoralists residing in a fraction where the wells are located had priority of access, while

non-resident pastoralists needed prior arrangements from the fraction chief and by the

owner of the fork for working the pulleys for lifting water. If the water of the well is

limited, the non residents are asked to move to other wells. Usually, the well users were

not required to pay taxes with the exception of the Tabahockomat well (Table 1) where a

pastoral committee taxes the users at 10 F cfa ($0.01) for 20 liters of water.

The residents of the fraction and non-residents contributed to the digging of new

wells and maintenance of existing wells. The contribution could be in terms of money or

labour. According to my informants, there were strict regulations as to who may dig wells

in the territory of each fraction. The decision comes from the chief of that fraction. He

too may not have authority for the development of wells until the fractions traditional

superior grants such permission. This was the case of El Sidi Cedeq and Ahel Lawal

fractions where the last decision comes from Ahel Lawal’chief (Table1).

Drawing of water from the deep wells involved animal tractions using systems of

fork, pulleys and ropes tied to animals (Fig7). A fork was made from tree trunks. Holes

through which pulleys rotated were made through the tree trunks, the pulleys made from

Balannites aegyptiaca or Acacia raddiana. The pulleys were made by craftmen and

highly priced. A pulley on average cost 3000 to 4000F (CFA) an equivalent of $5.45 to

11

$7.27. The pulley, ropes and bucket for drawing water were private and were not left at

the wells but transported to the camps (tents) after watering. The watering is by skin

buckets of about 15 liters tied to a rope which was passed over the pulley and the other

end tied to traction animals. Usually, pairs of donkeys (Fig7) or camel were used. The

animals are driven for a distance of up to 80-150 m to lift the water container from the

well. After water was of pulled and poured into a trough the traction animals were driven

closer to the well, the process which allowed the lowering of the rope into the well and

the process of pulleys, the water container were repeated again. Individual wells may be

operated by multiple pulley systems, which varied from well to well, related to the depth

and amount of water.

Individual families using the wells may have their own fork. For the wells included

in the current study, the numbers of forks varied from 2 to 9 (Fig6). A fork was owned by

a person or a tent but a large group of people used someone’s fork when the owner was

absent but after gaining permission. If the animals of the owner of the fork returned, he

would usually take over the use of the fork and the pulleys although the outsiders might

not have finished watering their animals. The implications being that the rights to the use

of the wells were different between the members of fraction and the outsiders. I was told

that most conflicts arose when the outsiders refused to give up using the fork. One such

case occurred in 1996 when there was misunderstanding among the users over the

Inamankor well (Table 1). The conflict was settled by the community at the water points

and any outstanding issues settled at the pastoral tents. If not settled such conflicts

sometimes resulted in fatalities, particularly during years of water and pasture shortages.

However, such conflicts were rarely reported to the government authorities. When I

asked why every body in the fraction did not make their own fork in order to avoid

conflict, I was told, in the case of Inamankor well, the patriachal parent was the first to

come in the area and established ownership over the well that has been dug by others

between 1913-1914. The patriarchal head was responsible for removing the sand,

repairing the well and thereafter his family took responsibility for managing the well.

Similarly, an elder claimed that the Tintates well (Table 1) was dug by his ancestors.

Thus, according to the local custom of the Arabs and the Touareg nomads of Azaoud, the

wells belonged to the family whose ancestor first initiated the digging.

12

Fig6. Traditional well with four forks

13

Fig7. Pairs of donkeys watering at Traditional well

3.2. Effects of radial distances on plant cover, species richness

Radial distances had significant effects on plant cover, species richness (all p<

0.001). Annual and perennial covers increased away from the wells and were unchanged

between 200-800 m (p < 0.001, Fig8b, Fig8d). Grass cover, when the data of perennial

and annual covers were combined occurred also unchanged between 200-800 m. This

indicated that a large amount change in plant cover occurred within 800 m of the wells

(p<0.001, Fig8a). Even in transects most distant from wells, grass cover did not exceed

5%. We found significant difference between annual and perennial mean cover (p

<0.001). Perennial mean covers differed significantly for all the wells (p = 0.8, Fig11b).

Moreover, annual mean cover also differed significantly for all Traditional wells (p

<0.001, Fig11a). At species level, over fifteen annual species, six perennial species and

six tree species were recorded. Cover and frequency of Boerhavia repens (p<0.0001,

Fig9b, Fig10b), Gisekia pharnacioides (p<0.0001, Fig9c, Fig10a) and

14

Trianthema pentandra (p<0.0001, Fig9a) increased away from the wells. The remaining

species (all p>0.05, Table2) and woody cover (p = 0.52, r2 = 0.11, Fig8c) did not appear

to vary with distances from wells. Grass species richness (p<0.0001, r2 = 0.94, Fig12a)

also increased with distances and the fit of the regression was good. However tree species

richness did not appear to respond (p = 0.70, r2 = 0.01, Fig12b).

Table2. Grasses species cover along radial distance from Traditional wells in the haoussa region. Species Autors Distance (m) . 400 600 800 1000 1200 1400 Aristida mutabilis (Trinius, Carl Bernhard von) + + +

Boerhavia repens (Linnaeus, Carl) + + + + + +

Cenchrus biflorus (Roxburgh, William) + + +

Cenchrus prieuri (Kunth, Karl Sigismund) +

Corchorus tridens (Linnaeus, Carl) + + + +

Dactyloctenium aegyptiacum (Willd, H.B) + +

Eragrostis tremula (Lamarck, Jean Baptiste) +

Fagonia cretica (Linnaeus, Carl) + +

Gisekia pharnacioides (Linnaeus, Carl) + + + + + +

Indigofera Senegalensis (Lamarck, J. B.A.P.M) + + + + + +

Indigofera astragalina (Candolle, Augustin .P) +

Indigofera strobilifera (Hochst) + + + +

Mollugo nudicaulis (Lamarck, J.B.A.P.M) +

Trianthema pentandra (Linnaeus, Carl) + + + + + +

Tephrosia bracteolata (Guillemin, J.B.A) +

Acacia sieberiana (Candolle, Augustin .P) + + +

Aerva javanica (Juss) + + + +

Colocynthis citrullus (Kuntze, Carl Ernst Otto) +

Cyperus jeminicus (Rottbøll, Christen Friis) + + + +

Cyperus conglomeratus (Thwaites, G.H.K) + + +

Panicum turgidum (Forsskål, Pehr) + + + + +

15

(a) (b)

(c) (d) ccC

distance (m)

gra

ss c

ov

er

(%)

140012001000800600400200

6

5

4

3

2S 0.551289R-Sq 70.3%R-Sq(adj) 65.9%

an

nu

al co

ve

r (%

)200

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

distance (m)140012001000800600400

S 0.383295R-Sq 80.1%R-Sq(adj) 77.2%

distance (m)

wo

od

y c

ov

er

(%)

140012001000800600400200

20

15

10

5

0

S 5.28006R-Sq 11.3%R-Sq(adj) 2.4%

distance (m)

pe

ren

nia

l co

ve

r (%

)

140012001000800600400200

2.00

1.75

1.50

1.25

1.00

0.75

0.50

S 0.183808R-Sq 68.9%R-Sq(adj) 64.3%

Fig8. Relationship between plant cover and radial distances from Traditional wells in Haoussa region, for (a) grass, (b) annual grass, (c) woody, (d) perennial grass.

16

(a)

Distance (m)

T.pe

ntan

dra

cove

r (%

)

140012001000800600400200

0.35

0.30

0.25

0.20

0.15

0.10S 0.0286255R-Sq 88.2%R-Sq(adj) 86.4%

(b) (c)

Distance (m)

B.re

pens

cov

er (

%)

140012001000800600400200

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

S 0.0666770R-Sq 84.7%R-Sq(adj) 82.5%

Distance (m)

G.ph

arna

cioid

es c

over

(%)

140012001000800600400200

0.5

0.4

0.3

0.2

0.1

S 0.0273882R-Sq 94.2%R-Sq(adj) 93.4%

Fig9. Relationship between plant cover and radial distances from Traditional wells in Haoussa region, for (a) T. pentandra, (b) B. repens, (c) G. pharnacioides.

17

(a) (b) 400

Distance (m)

G. ph

arna

cioi

des

freq

uenc

y (%

)

140012001000800600200

3.5

3.0

2.5

2.0

1.5

1.0

S 0.180728R-Sq 91.9%R-Sq(adj) 90.7%

Distance (m)

B. r

epen

s fr

eque

ncy

(%)

140012001000800600400200

15.0

12.5

10.0

7.5

5.0

S 1.22217R-Sq 88.7%R-Sq(adj) 87.0%

Fig10. Relationship between grass species frequency and radial distances from Traditional wells in Haoussa region, for (a) G. pharnacioides, (b) B. repens

(a) (b)

Fig11. Mean (±SE) for Annual grass cover (a) and Perennial cover (b) showing response with wells

Wells

Pe

ren

nia

l g

rass c

ov

er

(%)

TintatesTamayortTabahockomatSidi MousseInamankorClanssare

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0Wells

An

nu

al g

rass

co

ve

r (%

)

TintatesTamayortTabahockomatSidi MousseInamankorClanssare

8

7

6

5

4

3

2

1

0

18

(a) (b)

distance (m)

gra

ss s

pe

cie

s ri

chn

ess

140012001000800600400200

1.50

1.25

1.00

0.75

0.50S 0.0706131R-Sq 94.7%R-Sq(adj) 93.9%

distance (m)Tr

ee s

peci

es r

ichn

ess

140012001000800600400200

0.06

0.05

0.04

0.03

0.02

0.01

0.00

S 0.0205641R-Sq 1.5%R-Sq(adj) 0.0%

Fig12. Relationship between plant species richness and radial distances from Traditional wells in Haoussa region, for (a) grass, (b) Tree.

19

3.3. Effects of grazing pressure on plant cover and species richness

Grass cover (p<0.001, r2 = 0.41, Fig14a) and grass species richness (p<0.001,

r2 = 0.68, Fig13) decreased linearly in relation to grazing pressure. Only, covers of

B. repens (p<0.0001, r2 = 0.68, Fig14d), G. pharnacioides (p <0.0001, r2 = 0.63, Fig14c)

and T. pentandra (p<0.0001, r2 = 0.58, Fig14b) showed negative correlation to grazing

pressure.

66.7%R-Sq(adj)68.1%R-Sq

0.165488S

0.50

0.75

1.00

1.25

1.50

Light Moderate HeavyGrazing pressure

Gra

ss s

peci

es r

ic

h

nes

s

Fig13. Relationship between grass species richness and grazing pressure

20

(a) (b)

T. p

enta

ndra

cov

er (

%)

56.3%58.2%

0.0513330SR-Sq R-Sq(adj)

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Light HeavyGrazing pressure

Moderate

38.6%R-Sq(adj)41.3%R-Sq

0.739512S

2

3

4

5

6

Light Heavy

Gra

ss c

over

(%

)

Grazing pressureModerate

(c) (d)

67.4%R-Sq(adj)68.8%R-Sq

0.0909408S

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Grazing pressureModerate

62.0%R-Sq(adj)63.7%R-Sq

0.0654519S

0.1

0.2

0.3

0.4

0.5

Light HeavyGrazing pressure

Moderate

G. p

harn

acio

ides

cov

er (

%)

B. r

epen

s co

ver

(%)

Light Heavy

Fig14. Relationship between plant cover and grazing pressure, for (a) grass, (b) T. pentandra, (c) G. pharnacioides and (d) B. repens

21

3.4. Age of wells as predictors of plant cover and species richness

When we combined grass species richness data for Tintates and Tamayort in age

category 3-45 (youngest), for Inamankor and Tabahakamat in age category 150-350

(oldest), for Clanssar and Sidi Mousse in age category 60-80 years, the analysis showed

grass mean species richness to differ for age categories 150-350 to age category 3-45

years and 60-80 years (p<0.0001, Fig15a), but did not for age category 60-80 and 3-45

years. The higher grass mean species richness was found for the oldest category of 150-

350 years. Grass mean cover differed significantly for all age categories (p<0.002,

Fig15b). Higher grass mean cover was in youngest category 3-45 years (6.1%).

(a) (b)

0

1

2

3

4

5

6

7

8

9

3-45 150-350Age category (years)

60-80

0.0

0.2

0.4

0.6

0.8

1.0

1.2

3-45Age category (years)

60-80 150-350

Gra

ss m

ean

cov

er (

%)

Gra

ss s

peci

es r

ich

nes

s

Fig15. Mean (±SE) for grass species richness (a) and grass cover (b) showing response to Age category of wells.

22

Chapter 4 4. Discussion

4.1. Wells ownership and management We found, the traditional wells in haoussa region to be the property of the fraction.

The wells users were not required to pay taxes for access to water but could contribute

labour for the maintainance of the well. In this regard excludability over water points

poses problems when decentralisation in mali encourages control over local resources.

The only exception for the Tabahockomat well where a pastoral committee taxes 10 F cfa

($0.01) for 20 liters of water for which the initiative was purely external encouraged by

NGOs. The community at large considers this as interferance of the traditional system of

water management.

Under the traditional system, the ownership strengths the social relation in the

fraction and the wells are constructed with the resources of the fraction thereby the

fractions are committed for their maintenance in contrast. The wells created under donor

funded programs, very often experienced conflict because they lacked clearly laid down

procedures for priority over use of the wells (de Boer, 2000). We found powerful

traditional institutions could contribute to rangeland biodiversity conservation through

strict restriction of access and control on animal numbers watered at each well.

The decision to do so is a long and complex process. The reason for restricting the

rights to dig new wells is linked to pasture management. For individual fractions, herders

are concerned that development of more wells will have pulling effects of other

pastoralists into their territories that would result in overexploitations of the pastures.

Wells in Haoussa region are operated by animal tractions. For wells deeper than 40 m

that use camel traction amount of water extracted is up to 500 liters per hour (de Boer,

2000). This limited yield of water may be environmental friendly. Another study comes

to confirm that management type of water plays important role. Privately managed

boreholes have few livestock numbers than do group and government managed boreholes

(Roe and Fortman. 1981). In Northern Senegal, routes leading to the wells are closed

after a period of five years to allow vegetation to generate while others that have been left

as fallow are used (Toure, 1988).

23

4.2. Effects of radial distances on plant cover, species richness

Our finding showed that radial distances have significant effects on plant cover,

species richness. Grass cover and grass species richness were after 800 m from the wells,

while in the piosphere zone the vegetation indicators were highly impacted. One reason

why the 800 m zone had greater cover and species richness was probably being a

transitional zone, animals walking to water spent less time in the area. The area also takes

the benefits of rest during the wet season when the herds are moved from the wells.

However, around the wells, the impacts on vegetation indicators were greater because of

greater concentrations and trampling. As in other studies conducted in Namibia, the

grass cover increased with increasing distances from water points (Nangula & Oba.

2004). We found significant difference between annual and perennial mean cover which

could be attributed to time and useful rain. In 2005, when the present research was

conducted the area received the heaviest rainfall of 223.2 mm and at the time of

collecting the data the livestock was mostly far from wells relying on surface water. The

lower stocking density (estimated at 0-16 Goats/km2) allowed annual grasses to

germinate, confirming what others have reported that closer to water points annual

grasses is more abundant during the wet season (James, al. 1999). In the areas

immediately close to the wells i.e. 100-200 m continuous trampling (Lange,1969) and

heavy grazing might change grass species composition (Larsson, 2003) ). In other studies

it has been shown that perennial plant cover increased rapidly away from watering points

(Todd, 2006). In our study, Boerhavia repens, Gisekia pharnacioides and Trianthema

pentandra covers increased away from the wells implying that the species were sensitive

to livestock grazing and heavy tramping. The remaining species and woody covers did

not appear to vary with distances from wells. Furthermore, radial distances from water

points had significant effects on herbaceous species richness (Nangula & Oba. 2004;

Todd, 2006). Overall, increased plant cover and species richness away from the wells

could be largely attributed to reduced tramping and grazing pressure. A previous study

conducted by Deyoko (2005) discounted the effects as a reponse of soil texture. In the

study area the sub desert soil appeared to have had little influence on the variations of

plant cover and plant species richness. The crucial factor was rainfall and soil moisture

(de Leeuw, Diarra & Hiernaux, 1993)

24

4.3. Effects of grazing pressure on plant cover and species richness

Plant cover and grass species richness decreased linearly in relation to grazing

pressure gradients. Only, the cover of B. repens, G. pharnacioides and T. pentandra

showed negative correlations with grazing pressure. The finding supported the evidence

that provision of water points rises grazing intensity (Van Rooyen al. 1994). In other

regions such as the semi and humid areas of southern Africa heavy use around water

points resulted in bush encroachment (Martens. 1971; Wergen. 1977; Tolsma, al. 1987;

Skarpe, 2000) which was not evident in Northern Mali. The impact of grazing pressure

around water points showed a general trend as reported for southern Africa and south-

western and North-America (Jeltsch, al. 1997). Since livestock are more likely to walk

closer to get watered plant cover and species richness are likely to be impacted by

livestock grazing; Boerhavia repens, Gisekia pharnacioides, Trianthema pentandra are

palatable to livestock and might constitute important component of forage.

4.4. Age of wells as predictors of plant cover and species richness

Grass mean species richness differed for age categories 150-350 to 3-45 years and

category 60-80 years, but did not for 60-80 and 3-45 years. Higher grass mean species

richness was found for the oldest category 150-350. Grass mean cover differed

significantly for all age categories. Higher grass mean cover was in younger category of

3-45 years. Increase in age of wells might increase species richness but progressive loss

of plant cover. This is in contrast to the studies conducted in Namibia where herbaceous

species richness declined in response to water point age (Nangula & Oba. 2004). In

response to the age of water sources, gradual negative changes in desirable species

composition and vegetation cover, has been reported by others (Larsson, 2003).

25

Chapter 5

5. Summary

In Haoussa (northern Mali), the traditional wells ownership was maintained by

individual fractions. A fraction refers to a territory with spatial delimitation. The fractions

were responsible for wells management and control access to the wells by people from

outside the fractions. The wells users were not required to pay taxes whether residents or

non-residents. Radial distances from wells had negative effects on plant cover and

species richness. Annual and perennial cover increased away from wells and unchanged

from 800m but annual grass was dominant. However, woody cover and tree species

richness did not appear to vary with distances from wells. At species level, only cover

and frequency of Boerhavia repens, Gisekia pharnacioides and Trianthema pentandra

increased away from Traditional wells, suggesting that B. repens, G. pharnacioides and

T. pentandra were in majority and fairly distributed across radial distances from wells.

Grass species richness also increased with distances. Plant cover and grass species

richness decreased linearly in relation to grazing pressure. Only, cover of Boerhavia

repens, Gisekia pharnacioides and Trianthema pentandra showed negative correlation to

grazing pressure, suggesting B. repens, G. pharnacioides and T. pentandra are palatable

to livestock and constitute important component of forage. The highest grass mean cover

was found in younger category 3-45 years while the oldest category 150-350 years

showed the highest grass mean species richness; suggest age of wells played an

influential role. Increase in age of wells might increase species richness in contrast to

grazing pressure but progressive loss of plant cover. Over all, increased in plant cover

and species richness away from wells were largely attributed to reduced tramping and

grazing pressure.

26

References

Andrew, M. H. and Lange, R. T. (1986) Development of a new piosphere in arid

chenopod shrubland grazed by sheep. I. changes to the vegetation. Australian

Journal of Ecology, 11: 395-409.

Bernus, E. (1974) Les Illabakan (Niger). Une Tribu Touareg sahelienne et son Aire de

Nomadisation. Paris O.R.S.T.O.M.

Brooks, M.L., Matchett, J.R. & Berry, K. (2006) Effects of livestock watering sites on

plant communities in the Mojave Desert, USA. Journal of Arid Environment, in

press.

Centre de Recherche Agronomique de Gao (CRA).2002

de Boer, S. (2000) Echo evaluation: Water and rural development northern Mali and

northern Niger.

Deyoko, A.(2005) Chema Directeur D’ urbanisme de Bamba, Mali.

Departement de meteorologie. (2005) Mali.

de leeuw, P.N., L. Diarra. & P. Hiernaux. (1993) An analysis of feed demand and supply

for pastoral livestock: the Gourma region of Mali. PP.136-152 in R.H. Behnke Jr., I,

Scoones and C, Kerven (eds) range Ecology of disequilibrium. New Models of

Natural variability and pastoral Adaptation in African savannas.

London: ODI, IIED& common wealth secretariat.

Fleischhauer, E., Bayer, W., Lossau, A. Von. (1998) Assessing and monitoring

environmental impact and sustainability of animal production.

Gallais, J. (1967) Le delta interieur de Niger: Etude de Geographie Regionale. Memoires

de l’IFAN, 79,2 volumes. Dakar: IFAN.

Hiernaux. p (1992) The crisis of sahelian pastoralism: Ecological or Economics?

Hanan, N., Prevost, Y. & Diouf, O. (1991) Assessment of desertification around deep

wells in the Sahel using satellite imagery. Journal of Applied Ecology, 28: 173-187

James, C.D., Landsberg, J. & Morton, S.R. (1995) Ecological functioning in arid Autralia

and research to assist conservation of biodiversity. Pacific conservation biology,

2:126-142.

27

James, C.D., Landsberg, J., Morton, S.R. (1999) Provision of watering points in the

Australian arid zone: a review of effects on biota. Journal of Arid Environments,

41:87-121.

Jeltsch, F., Milton, S.J., Dean, W.R.J. & Van Rooyen, N. (1997) Simulated pattern

formation around artificial waterholes in the Semi-arid Kalahari. Journal of

Vegetation Science, 8:177-188.

Lange, R.T. (1969) The piosphere: sheep track and dung patterns. Journal of Range

Management, 22:396-400.

Landsberg, J. & Stol, J. (1996) Density and spatial distribution of sheep, kangaroos and

feral goats in woody rangeland paddocks in north-western New south Wales.

Rangeland Journal, 18: 270-291.

Larsson, H. (2003) Water distribution, grazing intensity and alterations in vegetation

around different water points, in Ombuga grassland, northern Namibia.

Marie, J. (1977) Stratégie traditionnelle d'adaptation à la sécheresse chez les éleveurs

saheliens: pertes en Betail, Mobilite’, Ethnie.

Martens, J.E. (1971) The effects of tribal grazing patterns on the habitat in the Kalahari.

Botswana Notes and Records special Edition, 1:234-241.

Nangula, S., Oba, G. (2004) Effects of artificial water points on the Oshama ecosystem in

Namibia. Environmental conservation 31(1): 47-54.

NCGIA-Center for Geographic Information and Analysis. UNEP/GRID-SIOUX FALLS - Sioux Falls, United Nations Environment Programme. (2001)

Roe, E., Fortman. (1981) Water use in Eastern Botswana: policy guide and summary of

the water points survey.

Reseau d’Observatoire et de Surveillance Ecologique a Long Terme. Bourem (2003)

Mali.

Sharpe, C. (2000) Desertification, no-change or alternative states: can we trust simple

models on livestock impacts in dry rangelands? Applied vegetation science 3: 261-

268.

Thomas, D.S.G., Sporton, D. & Perkings, J. (2000) The environmental impact of

livestock ranches in the Kalahari, Botswana: Natural resource use, ecological

change and human response in a dynamic dryland system. Land Degradation and

development 11: 327-341.

28

Thrash, I. (1993) Implications of providing water for indigenous large herbivores in the

Transvaal lowveld. Ph.D. Thesis, University of Pretoria, Pretoria.

Thrash, I. (1998) Impact of water provision on herbaceous vegetation in Kruger National

park, South Africa. Journal of Arid Environment, 38: 437-450.

Thrash, I., (2000) Determinants of the extent of indigenous large herbivore impact on

herbaceous vegetation at watering points in the north-eastern lowveld, South Africa.

Journal of Arid Environments, 44: 61-72.

Todd, S. W. (2006) Gradients in vegetation cover, structure and species richness of

Nama-Karoo shrubland in relation to distance from livestock watering points.

Journal of Applied Ecology, 43: 293-304.

Toure, O. (1988) Pastoral environment in of northern Senegal. Review of African

political economy.

Tolsma, D. J., W.H.O. and Verwey, R. A. (1987) Nutrients in soil and vegetation around

two artificial water points in Eastern Botswana. Journal of Applied Ecology, 24:

991-1000.

Van Rooyen, N., Bezuidenhout, D., Theron, G.k & Bothma, J.d.p. (1990) Monotoring of

the vegetation around artificial watering points (windmills) in the Kalahari

Gemsbok National park. Koedoe, 33:63-88.

Van Rooyen, N., Bezuidenhout, D., Theron, G.K., Bothma., J.du P. & Le Riche, E.A.N.

(1994) Vegetation gradients around artificial Watering points in the Kalahari

Gemsbok National park. Journal of Arid Environments, 26:349-361.

Wergen, M.J.A. (1977) Effects of game and domestic livestock on vegetation in Eastern

and southern Africa. In: Krause, W. (Ed.), Application of vegetative science to

Grassland Husbandry. Handbook of vegetation science, No.13, PP.147-159. The

Hague: Junk. 535 PP.

29

Appendix Questionnaires

Village: Date:

Respondent name: interviewer name:

1-what do you do as main activities in rainy season? …………………………………………………………………………………… ………………………………………………………………….. 2-What do you do as main activities in dry season? …………………………………………………………………………………………… ……………………………………………………………………………………………. 3-do you have: Sheep Yes No Cattle Yes No Camels Yes No Donkeys Yes No 4-how many well do you have around? ………………………………………………………………………………. ………………………………………………………………………… ……………………………………………………………………. 5-To whom do well do belong? ………………………………………………………………………………….. ……………………………………………………………………………. ……………………………………………………………………………… …………………………………………………………………………………. 6-Do you have rules of using the wells Yes No 7-How do the rules function? ……………………………………………………………………………………… ………………………………………………………………………………

30

8-Do the rules in respect by the users? ……………………………………………………………………………………………………………………………………………………………………………………….. ………………………………………………………………. 9-what explain the no respect of rules by the users? ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… 10-Do you have any conflict around the wells? Yes no 11-Tell me about different conflict happed and the year …………………………………………………………………………………………….. …………………………………………………………………………………. ……………………………………………………………………. 12-what could be the cause of conflict? …………………………………………………………………………………………….. …………………………………………………………………………………………. …………………………………………………………………………… 13-How the conflict is resolved? ………………………………………………………………………………………. ……………………………………………………………………… 14- Are the conflict resolution strategies effective ? …………………………………………………………………………………. ………………………………………………………………………………… 15-Do animals graze around the well in rainy season? Yes no Why……………………………………………………….. ………………………………………………………… ……………………………………………………………………………………… 16-How do you take out water from well? ………………………………………………………………………………………. ……………………………………………………………………….

31

17-do you know the age of this well ………………………………………………………………………………………….. …………………………………………………………………………… …………………………………………………………………………………………. And its size? ……………………………………………………………………………………………………………………………………………………………………… 18-Do you use well in: full year: dry season: rainy season: why ……………………………………………………………………………………………… …………………………………………………………………………………. ……………………………………………………………….. 19-Do this well a permanent source of water in use? …………………………………………………………………………….. ………………………………………………………………………………………….. ………………………………………………. 20-Do both animals and human use the same well for drink? ………………………………………………………………………………………………………………………………………………………………………………………… 21-do you know any disappeared tree around the well? ……………………………………………………………………………………………………………………………………………………………………………………………… 22-do you know any unfunctional well? …………………………………………………………………………………………………………………………………………………………………. 23-What are the most used wells? …………………………………………………………………………… ……………………………………………………………………… 24-How many livestock/persons are supplied in water by this well? …………………………………………………………… ………………………………………………………………………….. 25-Do you wish many wells? …………………………………………………………………………………………………………………………………………………………………………………….

32

And why ……………………………………………………………………………………. …………………………………………………………………………………………

33