Small ruminants in environmental conservation

A. El Aicha,*, A. Waterhouseb

aDepartement des Productions Animales, Institut Agronomique et Veterinaire Hassan II, BP 6202, Rabat, MoroccobSAC, Hill and Mountain Research Centre, Auchincruive, Ayr, Scotland, UK

Abstract

This paper presents the main social and economic in¯uences of small ruminants on the environment as well as the impact of

small ruminants on natural resources in two of the most dominant world farming systems, arid and temperate. The analysis of

the arid system underlined the apparent incapacity of the land to support the numbers of domestic animals that caused most of

the damage in addition to that accomplished through cultivation and gathering of wood species. The ecological integrity of

these systems was weakened once the strategies behind their adaptation to arid and marginal areas (diversi®cation and

mobility) were threatened. In addition, the transformation that these systems are going through (social, economical and

political) has threatened the viability of these traditional systems. In temperate zones, there are concerns that both too little and

too much grazing by small ruminants is leading to environmental degradation. There is a need to more fully understand the

role that grazing plays in maintaining habitats and landscapes in favorable condition. Environmental concerns of small

ruminant systems in intensive grassland systems are those of all intensive grassland systems, pollution from animal waste,

from silage, and nitrate and phosphate discharge to water. # 1999 Published by Elsevier Science B.V. All rights reserved.

Keywords: Small ruminants; Environment; Farming systems; Natural resources; Overgrazing

1. Introduction

The world small ruminants population was 1.7

billion in 1993 (65% sheep and 35% goats) of which

42% were in Asia, 22% in Africa, 11% in Australia,

8% in Europe and 7% in South America (FAO, 1993).

Population data for small ruminants showed a 10%

total increase during the last 20 years, with higher

®gures in the more arid regions, 20% and 19% for Asia

and Africa, respectively (FAO, 1993). Small rumi-

nants distribution shows that almost 2/3 of the world

goat and sheep population are on range lands, pastures

and rough grazing represent around 70% and 62% of

the land in Asia and Africa, respectively (FAO, 1993).

Sheep and goats are opportunistic and have been

always important sources of protein throughout the

world. The utility of sheep and goats goes beyond

obvious economic concerns. They convert low-quality

resources to high quality protein and in the mean time,

if well managed, they maintain and enhance the land-

scape.

The impact of small ruminants can be positive in the

sense that they conserve the environment, or disas-

trous if they degrade the environment. Negative

impact leads in certain circumstances to deserti®ca-

tion. Deserts created as a result of man's activities

extend over 9 million km2 (OECD, 1985). They are an

integral part of the farming system and impact with the

farm environment, both the socio-economical and the

ecological environments. The objectives of this paper

Small Ruminant Research 34 (1999) 271±287

*Corresponding author.

0921-4488/99/$ ± see front matter # 1999 Published by Elsevier Science B.V. All rights reserved.

PII: S 0 9 2 1 - 4 4 8 8 ( 9 9 ) 0 0 0 7 9 - 6

are to: review two of the most dominant farming

systems in an environmental perspective, discuss

the main social and economic in¯uences of small

ruminants on the environment, present and discuss

the impact of the small ruminants on natural resources,

and address some methodological and research issues.

2. Major farming systems

In this section we review two of the most dominant

farming systems in an environmental perspective,

farming systems within arid regions and farming

systems within temperate zones.

2.1. Farming systems within arid environment

According to Le HoueÂrou (1996), arid zones where

trading crops are not possible without irrigation

occupy 14.6 million km2 (11% of the earth surface).

Semi-arid and hyper-arid areas occupy another 10%

and 11.2% of the earth surface, respectively.

Typically, in arid regions, pastoralism and agro-

pastoralism are the most common production systems

where livestock, the main activity, is associated with

subsistence cropping. Even though forms of organiza-

tion of these systems are in¯uenced by factors of

different nature, history, culture, economics and level

of technology, the production systems within arid

environments rely on two strategies, diversi®cation

in subsistence activities, herd composition and mobi-

lity of herds. Mobility and diversi®cation sustained

these systems for long periods and made them pro-

ductive. Many authors have indicated that in such arid

environments, mobility of herds made them produce

more and resist better to drought than sedentary in the

same conditions (Breman and de Wit, 1983). In addi-

tion, migrating herds caused less environmental degra-

dation, except in areas of animal concentration such as

around the water boreholes.

Diversi®cation takes many forms, in activities and

in herd constitution. Diversi®cation of subsistence

activities between agriculture and livestock is an

essential way to cope with climatic risk. Indeed,

animals may survive even when grain yield is low.

In addition, diversi®cation of crops grown is usually

considered a way to overcome the risk of crop failure.

The other type of diversi®cation concerns herd con-

stitution. Producers prefer to have a lot of animals

(especially females) of different kinds and mixture of

animal species in their herds. Proportion of the dif-

ferent species (camel, cattle, sheep and goats) varies

according to regions. As the environment gets more

arid, proportion of cattle diminishes while that of

goats and camels increases. The diversity of kinds

of animals and having large proportions of females

ensures rapid recovery from stressful situations such

as droughts.

Diversi®cation is one way to cope with the harsh

environment. Mobility of herds is another one since it

reduces environmental stress and personal risk. Small

ruminant herds in these arid regions are rarely con-

®ned to the same pasture year-round. They rely on

movements that permit adjustment to the spatial var-

iation of forage resources and water. Movements can

be done on a seasonal basis for transhumant pastor-

alism with relatively small amplitudes, less than

50 km for nomadic pastoralism, or movements are

perpetual with large amplitudes that reach 500 km or

even more. Movements to utilize range land resources

in these regions used to be according to institutions

that elaborated highly regulated land use systems for

conservation of standing forage such as `̀ Agdal'' in

the Atlas mountains of Morocco (Bourbouze, 1982) or

the `̀ Hema'' system on the Arabian peninsula (Draz,

1978, 1990).

The overwhelming problems of these pastoral and

agro-pastoral systems of the arid regions are: the

apparent incapacity of the land to support the numbers

of the domestic animals (Lamprey, 1990), even though

most of the damage to the environment is accom-

plished through cultivation and the gathering of wood

species; the mechanisms behind the adaptation to arid

and marginal areas have been weakened since diver-

si®cation and mobility have been limited which con-

strain the production sustainability in these

environments, and the transformation that these sys-

tems are going through (social, economical and poli-

tical) that has threatened the viability of these

traditional systems.

2.2. Farming systems within temperate environment

Within the world's temperate zones, small ruminant

production systems are found in two main situations.

Firstly, they are the main agricultural land-users in

272 A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287

areas where there are combinations of dif®cult terrain,

poor soils and harsher climates. The hill and mountain

regions are the main situation where small ruminants

play a central role in agriculture because of these

reasons. However, for some low land of poor quality

such as coastal heaths and marshlands, small rumi-

nants are also important. In all these places cropping is

dif®cult or impossible and other more intensive live-

stock enterprises are poorly suited. Secondly, small

ruminants utilize more intensive pastures. Here they

must either compete on equal terms with other enter-

prises, often using pastures in combination with cattle

or alternatively, on mixed and cropping farms, and

they provide the basis for a marginal enterprise using

poorer value grassland in combination with stubble.

2.2.1. Systems on hilly and mountainous regions

The land available to agriculture is often steep,

rocky and has poor soils. However, there is frequently

some better land available which may be available to

the small ruminant system. A high proportion of

pastures and woodland areas used by small ruminants

are semi-natural habitats and of high value for nature

conservation and landscape maintenance. Because of

the agility and hardiness of sheep and goats, the range

of their semi-natural habitats is undoubtedly greater

than for other livestock enterprises. Indeed in many of

these regions the current valued habitats and land-

scapes have been created by this farming of livestock

including small ruminants. For instance within Brit-

ain, the ®rst two of the three main landscapes identi-

®ed by Mitchell et al. (1996), `̀ Northern highlands'',

`̀ Bocage'' and `̀ Former open ®elds'' were heavily

in¯uenced by sheep production. The range of impor-

tant habitats on which sheep production in the hills and

uplands has an in¯uence includes upland dry heath

(heather moorland), blanket bogs, mountain heaths

and grasslands, acid grassland, calcareous grasslands,

and a wide range of woodland habitats.

Systems in the mountains and hills tend to be

dependent upon grasslands, both semi-natural and

improved, although in some regions browsing of

dwarf shrubs in the winter period is as important as

browsing of shrubs in the arid regions. In the true

temperate zones, sheep and goats have seasonal breed-

ing and in the hill regions, lambing is linked to

seasonal availability of pastures. It is normal for

lambing to commence at the beginning of the grass

growing season, with lactation occurring through the

period of highest grass growth and quality. Mating and

pregnancy typically coincide with the period of poor-

est growth and often the most dif®cult climatic con-

ditions.

There are a number of adaptations that cope with the

patterns of production and availability of pastures in

hilly regions.

Breeds. There is an enormous range in breeds using

the hill areas. Mason (1969) produced a list of over

240 European sheep breeds. These differ in size,

production capacity, hardiness, grazing behavior and

physical attributes such as wool type and color, car-

cass characteristics, presence of horns. In Britain and

Ireland, the strati®ed system of sheep breeding with

crossbred ewe lambs and ewes sold for breeding,

comes down from the higher hills, where they are

bred, to lower land. This is a particularly sophisticated

system, which combines the matching of genotype to

farming requirements and using the bene®ts of cross-

breeding (Cooper and Thomas, 1991).

Seasonal movement. Livestock moves from one

vegetation/climatic zone to another. Full scale trans-

humance, important for mountain regions is less

common in foothill systems, but most systems involve

movement of livestock from higher land to lower land

for winter grazing, or even into housing for part of the

winter. Conversely in spring, after parturition, the

stock tend to move upwards through a range of

pastures. This pattern has been described for Spain

and Greece by Beaufoy et al. (1994). Similar patterns

of transhumance are found throughout the Mediterra-

nean region. In Britain and Ireland, where breeds have

been selected to remain all year around on hill grazing

of poor quality, many farmers utilize improved pasture

in spring and autumn to improve lamb survival,

growth and proli®cacy in the two pasture system

(McClelland et al., 1985).

Low levels of input and output. This tends to be

geared to the more dif®cult environments in hilly

areas. Poorer land cannot sustain higher levels of

production of progeny or milk and there are physical

dif®culties in providing high levels of inputs in many

systems. However, there are variations. In the produc-

tive grass growing areas of Britain and New Zealand,

low levels of supplementary feed inputs are the norm,

whilst in some areas where there is high value demand

such as in northern Spain and southern France, then a

A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287 273

higher feed input is quite typical. The regions where

low input systems occur tend to have large ¯ock sizes

and the predominant system is sheep production for

heavy lamb. Goats are uncommon. For example,

Britain has over 20 million breeding ewes, a high

proportion kept in hill regions, with an average ¯ock

size of 297, but there are less than 100,000 goats kept

in very small ¯ocks. Milk production from sheep and

goats is extremely small in comparison to the scale of

lamb production, which is the dominant land use over

much of the hilly regions.

In the hill areas which lie closer to arid regions e.g.

in the Mediterranean, then small ruminant systems are

more varied, with many producing milk and meat, and

are composed of both sheep and goats. For instance,

the three northerly autonomous regions of Spain

(Cantabria, Asturias and Galicia) with temperate cli-

mate had some 280,000 breeding ewes and 92,000

does in 1992 (MAPA, 1994). Patterns of shepherding

also differ. In the range land systems common in the

hills of Britain, Ireland and New Zealand, sheep ¯ock

are retained on their own land by a mixture of fences

and by selection of breeds with strong home range

behavior. Shepherds do not stay with the sheep during

the day and the sheep graze as a very dispersed ¯ock

using most of the range available to them.

By contrast in many other temperate hill and moun-

tain systems, sheep and goats are kept in a tight ¯ock

by a shepherd constantly present with them. The key

difference in relation to environmental impact is that

with constant shepherding, the shepherd has a major

role in determining the grazing and browsing pattern,

whereas with un-shepherded home range systems the

individual sheep makes most of the foraging deci-

sions. Many environmental problems stem from social

changes which have changed the way that sheep are

tended.

2.2.2. Intensive grasslands

Small ruminant systems make considerable use of

intensive sown pastures throughout the world.

Because the grassland resource is of better nutritional

quality and more accessible, there tends to be much

more ¯exibility in production systems than for sys-

tems in harsher environments. Timing of parturition is

less related to seasonal grass production and may be

manipulated to achieve market requirements. There is

more ¯exibility in breed choice, though there tends to

be a tendency towards larger more productive breeds.

However, the grazing resource is often as well suited

to cattle as to small ruminants, so the small ruminant

enterprise needs to be economically comparable with

the other enterprises or complementary.

In the main grassland regions, meat production

from sheep is the main production system. As land

becomes more arid and often the size of enterprise

declines then combinations of milk production from

sheep and goats becomes more important. In these

systems, light-weight carcasses are a high value by-

product. In some areas, large fattening units for these

lambs and kids have been established. Use of semi-

natural pasture of high conservation value is much less

than in systems using mountain and foothills. How-

ever, small ruminants tend to be the species that use

the least productive land on these more intensive farms

and this may be of highest environmental value, often

because it has been least modi®ed by intensive meth-

ods. Environmental concerns of small ruminant sys-

tems in intensive grassland systems are those of all

intensive grassland systems, pollution from animal

waste, from silage, and nitrate and phosphate dis-

charge to water.

3. Main social and economic influences of smallruminants on environment

Analysis of the main systems in the perspective of

the environment underlined the importance of small

ruminants in converting resources into products, as

well as their role for economic diversi®cation. The

status of the resources of the environment (land and

vegetation) impacts both directly and indirectly on the

way small ruminants use natural resources. There is no

doubt that the transformations, that these systems are

going through, are widening the gap between the

utilization of natural resources and the ecological

reality of the environment.

3.1. Small ruminants and economic diversification

Goats and sheep play many roles and contribute to

the diversi®cation of the economy because they use a

variety of marginal land resources that they transform

to a multitude of products (meat, milk, wool, hair, hide

and dung). The low demand for labor and capital as

274 A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287

compared to cattle ensures that small ruminants con-

tribute more to economic diversi®cation than other

livestock enterprises.

Small ruminant breeding, especially goats, does not

require high capital and may help to upgrade to more

pro®table production. Le HoueÂrou (1981) reported

that due to its proli®cacy and rusticity, range goats

produce very high returns which make them one of the

best possible investment in the Southern and Eastern

Mediterranean. Usually, they are the only alternative

for populations living in marginal areas, which prevent

these areas from human deserti®cation.

3.2. Small ruminants and the land tenure

The status of natural resources in general, and land

tenure in particular, in¯uences the viability of the

natural resources. The ambiguity of land status, as

is the case in many areas of the Mediterranean region,

in¯uences small ruminants in two manners. On the one

hand, cultivation of rangelands by providing agricul-

tural by-products (straw, cereal grains, stubble, fallow)

improves the nutritional status of small ruminants. On

the other hand, the common use of communal range-

lands has contributed to their degradation. This status

of the land enhances the cultivation of the best parts of

the rangelands and reduces grazing areas to poorer

land and increasing the grazing pressure on the

remaining (Bourbouze and Rubino, 1992). Cultivation

rate on rangelands has been accelerated by the use of

tractors. Cultivation on range lands damages native

vegetation when it has been cut and makes soil more

vulnerable to wind erosion, especially after cropping

is abandoned as a result of low and decreasing yields

of cereals. Once these cultivated marginal areas

become abundant, their grazing values are almost

nil and it may take decades for the native vegetation

to come back. In Syria, in the last 30 years, degrada-

tion and the expansion of cultivation has almost

completely eliminated the shrub vegetation of the

steppe, which now provide only limited amount of

grazing in spring (Treacher, 1990).

In addition to cultivation, the collective status of

rangelands puts no incentive on control of animal

numbers. Even if lands are collectively owned, this

does not imply completely open and unregulated

access, which leads to a `̀ tragedy of the common''

situation such as described by Hardin (1968). Even

if the land is only open to potential users, it is still to

the advantage of the producer to add as many animals

as he can raise capital to purchase or he can contract

for.

3.3. Loss of cultural heritage and traditional

practices

As has been discussed earlier, the ecological integ-

rity of pastoral systems within arid regions to sustain

their natural resources depends on two strategies,

mobility and diversi®cation, which rely on institutions

developed by people living in these areas to regulate

land utilization. Such ecological integrity has been

weakened by causes of transformations, which these

systems are undergoing. Examples are the imposition

of European laws during periods of colonial rule and

government planning after independence. This dis-

functioning resulted in conversion of ecosystems to

open access systems since the elaborate institutions

that regulated land use have been lost. Another exam-

ple is the change in political conditions that imposed

the creation of national borders restricting movements

of animals across frontiers and thereby reduced the

diversity of ecosystems available to herders. This

resulted in increased duration of grazing certain areas,

because the strategies of pastoralists (mobility of

herds and diversi®cation of resources) were altered.

Deterioration of the environment under these pastoral

systems has been accelerated by climatic change,

economic change and population growth. Examples

of these phenomena are provided by the establishment

of the frontier between Uganda and Kenya with the

overgrazing and the destruction of the economy of the

Karamajong of Uganda (Quam, 1978). The con¯ict in

the Southern Sahara of Morocco, where the horizontal

movement of nomads has been interrupted since the

late 70s, is another example.

Reduction of mobility took place also in some

European mountainous regions where long transhu-

mance systems were established to move seasonally

sheep between areas in Greece and Spain (Beaufoy

et al., 1994). Indeed, transhumance has strong cultural

and nature conservation value. In Spain, there were

over 125,000 km of trails, of which the largest (CanÄa-

das) were 75±100 m wide. These are still important

habitats in their own right, once covering 450,000 ha

of Spain. It is estimated that between 15±40% of the

A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287 275

network has been completely lost. A typical transhu-

mance journey followed grazing in the high Pyrenees

above the tree line from June to October. The sheep

would walk 150 km to the Ebro valley where they

would graze cereal stubble and shrubby matorral. In

the spring, the sheep returned ®rst to lower altitude

pasture in the pre-Pyrenees, before again returning to

the high Pyrenees. At one time over 20% of all animals

would move, it is now estimated that the ®gure is less

than 2%.

Intensi®cation processes have also led to the loss of

traditional practices in the temperate zones. Hay

making which has high nature conservation value,

because it allows ¯owering and seeding and

encourages particular invertebrate assemblages

(Smith, 1997), is being replaced by silage production

in many of the grassland areas. Silage cutting takes

place earlier and there is considerable loss of biodi-

versity as a result.

3.4. Human population dynamics and social change

The impact on the environment by the decreasing

size of the agricultural labour force, changes in age

structure and lack of young people needs to be dis-

cussed. Frades et al. (1995) report that in the Los

Ancares region of Spain, there has been a 48% decline

in the population from 1950 to 1991, and now some

75% of the farmers are over 55 years of age with much

reduced ¯ock numbers.

Beaufoy et al. (1994) reported the changes occur-

ring in a typical Greek mountain village. Between

1980 and 1991, the number of shepherds dropped by

16%, the number of animals moving by transhumance

by 25% and the average age of the shepherds increased

from 57 to 63 years of age.

From interviews with policy makers, land managers

and farmer organizations in Spain and Britain, Ash-

worth et al. (1997) found that the aging population

associated with sheep and goat keeping was a common

concern in many areas of both countries. It was noted

that there was a considerable lack of new young

shepherds willing to graze their ¯ocks using tradi-

tional methods. These types of changes have been

associated with shrub ingress in many areas, leading to

loss of semi-natural grasslands but also to the

increased risk of ®re that can have other impacts on

the environment.

3.5. Support measures to retain small ruminant

farmers on the land and achieve environmental

benefits

Certain regions have recognized the key role that

small ruminant farming plays in maintaining habitats

and landscapes. In 1975, the EU introduced a council

directive on less favored areas (Council Directive,

1975). In these areas, notably mountainous and hilly

areas that are dif®cult to farm and frequently far from

markets, it was recognized that the higher production

costs made it dif®cult to achieve a level of income

comparable with that when employed in non-agricul-

tural businesses. The primary objective of the measure

was to `̀ ensure the continuation of farming, thereby

maintaining a minimum population level or conser-

ving the countryside''. Headage payments are made

on eligible breeding animals. However, there are

strong views, especially in the UK, e.g. the Wildlife

Trusts, 1996, that these support payments together

with other CAP payments have encouraged overgraz-

ing. Nevertheless, it is more generally accepted that

these measures have assisted in stemming the ¯ow of

populations and their livestock from rural areas and

prevented environmental damage through lack of

grazing.

3.6. Support measures to meet environmental

objectives

More speci®c environmental measures than

described above have been taken up within the EU

in the Agri-Environment Programs (Commission Reg-

ulation, 1992). The objectives include an environmen-

tally favorable extensi®cation of crop, sheep and cattle

farming including conversion of arable land to exten-

sive grassland, ways of using agricultural land which

is compatible with the protection and improvement of

the environment, countryside, landscape, natural

resources, soil and genetic diversity, including domes-

tic species, and the upkeep of abandoned farmland.

Within different member states, this has been applied

in relation to local priorities. In Britain, for instance,

there has been the establishment of the Environmen-

tally Sensitive Areas Scheme in 1987. There are now

43 such areas covering some 15% of the agricultural

land area of the UK (Swash, 1997). These schemes are

voluntary, requiring take-up from a menu of locally

276 A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287

speci®c prescriptions. In general these aim to maintain

and enhance the wildlife and conservation value of

each of the habitats for which the area is noted.

Examples of speci®c measures involving sheep man-

agement involves the establishment of management

plans for grazing of heather moorland, including

restrictive stocking rates, burning programs and care-

ful placement of supplementary feeding points to

avoid localized damage. In Spain, national schemes

have been established in 1995 which include plans to

maintain extensive cereal systems (in which grazing

by small ruminants are usually very important) and to

rear endangered livestock species. Under another EU

Regulation for Reforestation (EU Commission Reg-

ulation, 1992), ®nancial support is being made avail-

able to convert open farmland back to `̀ Dehesa''

(open oak woodland, under-cropped by extensive

cereals and grazed by livestock), which has unique

nature conservation and landscape values in central

Spain (Selby et al., 1996).

3.7. Changes related to the marketplace

Animal breeding and genetic selection has always

been a continual process. Introduction of novel ani-

mals and breeds to new locations and habitats has

taken place throughout history, and has frequently

had dramatic effects on the local ecology. In recent

years these wholesale changes and introductions have

been less extreme, but there are still considerable

changes underway, often relating to the changing

needs of the market, the changing production systems

of the farmer and the changed availability of farmers.

It has thus been common for breeds to change

dramatically.

Examples of such breed changes include the

marked reduction in less productive native breeds

and their replacement by more productive and more

market oriented breeds, e.g. the replacement of the

Herdwick breed in North-West England by the Swale-

dale, which produces more lambs including highly

valued ewe lambs for breeding on lowland farms

(MLC, 1988). In Southern France, the Lacaune breed

has displaced many local breeds, as farmers have

adapted new methods and new techniques and have

combined them to establish more ef®cient ways to

produce milk, particularly for the manufacture of

Roquefort cheese.

These breed changes have an impact on the envir-

onment in a number of ways. Firstly there may be

inherent differences between the animals replaced and

the new livestock. There are well-known differences

between the free ranging breeds that typify the range

land systems of New Zealand, Australia and Britain,

and those breeds that are shepherded on a constant

basis in cohesive groups (Arnold and Dudinski, 1978).

In Britain, Crofts and Jefferson (1994) have published

very detailed lists of grazing attributes of different

British sheep breeds, even though they are largely

anecdotal. Secondly, the different characteristics of

breeds lead the farmer to treat the animals differently.

Typically a move from a hardy native breed to a more

productive but less hardy one may in¯uence the way

that the farmer cares for the animal. Less hardy breeds

will tend to be grazed on better quality pasture and less

on poorer quality pasture. Where there are seasonal

differences in climate and productivity of grasslands,

the more productive breed will be retained on better

pastures or in housing for longer periods. Frequently

higher levels of supplementary feeding and higher

quality forages may be required. There may also be

differences in seasonality of production and timing of

different events, all of which will in¯uence natural

resource use.

3.8. The conflict between the political decisions and

the ecological reality of the environment

In some instances, the failure to understand the

functioning of the system leads to deterioration of

the production system. Political decisions to encou-

rage cultivation of range lands, to establish water

boreholes or to provide subsidized feed has impacted

negatively on the environment. Cultivation of range

lands not suitable for cropping, in addition to the

issues of land tenure discussed above, has been

favored by political priorities to ensure self-suf®-

ciency with cereals in many African countries.

Another illustration of this gap between political

decision making and environmental possibilities is

provided by the establishment of water points on range

lands. Indeed, boreholes instead of increasing avail-

able pastures as they are meant to do, they lead to local

deserti®cation and heavy livestock losses during

droughts. Water is a determinant factor in the nomad's

decision to move among grazing areas, such as the

A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287 277

southern part of Morocco, where he based his late

spring and early summer movements on the avail-

ability of water, while grazing areas lacking in water

during winter and early spring. Providing water in

winter grazing areas of these desert ecosystems makes

the nomad stay longer, which may threaten the via-

bility of the system and lead to deterioration of the

vegetation. The establishment of water points in some

areas without any grazing control has damaged range

land resources in countries such as Syria. Support and

subsidies by governments during droughts were pas-

sive, since herders could maintain herd numbers even

when range land resources were exhausted and lead to

overgrazing.

3.9. Transformation of small ruminant production

systems

Dynamics of productions systems in arid areas

under present demographic pressures and economic

changes, such as reduction in mobility of herds dis-

cussed above, lead to an increase in human settle-

ments, sedentarisation, which is associated with more

demand for cultivation land. As the population

becomes more and more sedentary, the amount of

agro-pastoralism increases. The environment is prob-

ably too variable to support an agro-pastoral system.

All these factors related to the transformation of the

pastoral systems make the systems heavily dependent

on external feed resources and agricultural by-

products.

These transformations concern also feeding and the

choice of raised breeds. Indeed, small ruminants rely

less on pastoral resources, i.e. they represent 6%, 12%

and 28% of the annual energy requirements of small

ruminants in Algeria, Tunisia and Morocco, respec-

tively (Bourbouze and Lazarev, 1991). In Saudi Ara-

bia, range forages provide less than 20% of the feed

needed by livestock (Sidahmed, 1992). During periods

of droughts, contributions of range lands might be

even lower. Along with this reduction in the contribu-

tion of range lands, other external resources and

agricultural by-products (straw, stubble) are offered,

which make the system heavily dependent on agri-

culture. However, the environment is probably too

variable to support an agro-pastoral system.

The dynamics of the pastoral systems induces also

changes in livestock composition, less goats and more

sheep and cattle. The intensi®cation of the systems

that generate forages, grain or other by-products leads

to modi®cation of the animals using these resources.

Therefore, more productive species are preferred to

well adapted ones leading to loss in rusticity. This is

happening in the Eastern Steppe of Morocco where the

Beni Guil native breed is replaced by the Ouled Jellal

coming from Algeria. The same phenomenon is occur-

ring in Tunisia where the fat tail breed (Barbarine

sheep) is invaded from Algeria by other more produc-

tive breeds.

In temperate regions, changing market conditions

and new technologies have led to elaboration of

productions systems that have detrimental impacts

on the environment. Zero grazing system induces

problems of pollution. Improving pastures with ferti-

lizing and reseeding in order to ®nish livestock in

upland areas, such as Wales and central France, affects

the landscape and the habitat structure (Egdell and

Dixon, 1996). In Europe, marginal livestock farming

is vulnerable to small changes in markets and sub-

sidies (Egdell and Dixon, 1996).

In other areas, the replacement of cattle with sheep

has been a process occurring throughout this century

in Western Scotland (Darling, 1955) and is still

increasing. The Islands of Lewis and Harris used to

have 10,000 breeding cows, but now these cows have

been reduced to less than 400 (McDonald et al., 1995)

and been replaced by sheep. This change to systems

with only sheep is seen as having many negative

environmental impacts, such as shorter sward height,

loss of traditional hay making for winter feed for cattle

and even the loss of dungpats, which are used by

ringed plover to lay their eggs in the Scottish Western

Isles (Jackson, 1988). The changes in sheep systems

alone are not the source of the problem, but rather it is

the cumulative impact of reduced cattle and increased

sheep numbers.

4. Environmental influences of small ruminantson natural resources

4.1. Environmental benefits of small ruminant

grazing

Grazing is ®rstly a process that prevents natural

succession, predominantly to trees and shrubs, and

278 A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287

secondly creates opportunities for rich and locally

characteristic plant communities and their associated

ecosystems. Loss or reduction in ruminant grazing, is

seen as a major problem in certain areas of the world.

The result is the ingress of shrubby plants (e.g. the

matorral in Spain) and eventually woodland. Impor-

tant grassland communities are lost without grazing

(Lombardi and Cavallero, 1996), as they are replaced

by succession to woodland. Further environmental

damage can occur through the lack of grazing in

traditionally grazed woodlands, where the lack of

®rebreaks and the dense ground ¯ora leads to larger

and more intense ®res that are no longer an acceptable

part of the woodland cycle, but are much more

destructive, killing trees and killing sheltering wildlife

through their greater intensity (Beylier and Rebattet,

1997). Many landscapes are maintained by a combi-

nation of the animals themselves and the direct work

of man to support his livestock. European examples

(Potter, 1997) include the complex mosaic of ®elds,

boundaries (hedges or walls) and small woodlands that

make up the bocage landscape, heather moorlands

which are prevented from succession to woodland

by combinations of grazing and ®re which provide

the open `̀ northern highlands'' landscapes of north-

west Britain and Ireland, and the `̀ Dehesa'' and

`̀ Montado'' woodlands of Spain and Portugal, where

under-grazing of the sparse oak trees is a key part of

the system.

Grazing is a disturbance that favors certain plant

communities and tends to lead to greater species

diversity mainly through creation of gaps (Grime,

1979). Many grasslands are maintained only by the

impact of grazing and more speci®cally by particular

prescriptions of species and seasonal use. For exam-

ple, many grasslands are maintained primarily by

grazing, and as Hopkins and Hopkins (1993) point

out, neglect (i.e. abandonment or cessation of tradi-

tional practices) is probably the greatest threat. In

Britain, it is accepted that certain grassland habitats

are best maintained by small ruminants compared to

cattle, because the former graze swards to shorter

heights than cattle.

Small ruminants themselves provide more speci®c

roles in the ecosystem. Their dung is an important

source of food for many insects and then for other

wildlife such as the European Chough, a rare bird

(McCracken et al., 1992), that provides a means for

seeds to travel to new areas, and they are valuable prey

and carrion for important large predators (Fuller,

1996; Donazar et al., 1997).

4.2. Degradation of natural resources

This results in decreased vegetation cover and

deforestation, which enhance soil erosion. Loss of

soil due to erosion averaged some 50 ton/ha/year. This

loss is at least ®ve times the natural rate of soil

formation (FAO, 1992). Worldwide, overgrazing by

domestic animals, especially small ruminants, caused

29% of the water erosion and 60% of the wind erosion.

Another important ®gure that should be underlined is

that most of the erosion (water and wind erosions) is

taking place in Asia and Africa, 65% and 67% for

water and wind erosion, respectively (FAO, 1992).

In most instances, forest and rangeland natural

resource degradation is a product of human activity.

Deserts created as a result of man's activities extend

over 9 million km2 (OECD, 1985). In arid zones,

phenomena such as overgrazing, the extensive cutting

of fuel wood and the cultivation of fragile lands

resulted in loss of plant cover and change in vegetation

composition.

Forests occupy some 26% of the land area of the

globe (FAO, 1992). Forests provide habitat for large

proportions of plant and animal species, conservation

of mountain watersheds, conservation of biodiversity

as well as fodder for livestock. Forest ecosystems are

subject to change due to natural causes and human

interventions.

The pressure on forest land and its loss to agricul-

ture is mainly a tropical problem. Yearly deforestation

rates average about 15.4 million ha (FAO, 1992). In

addition to the use of forests for agricultural purposes,

they are usually overused by grazing herds of neigh-

boring populations (El Aich et al., 1995). Forest

foliage (green oak leaves) is usually cut during winter

by herders and provided to goats when no other range

resources are available. In the High Atlas of Morocco,

during the same period, the animal species associated

to goats are either fed with stored farm resources

(cattle) or moved to better grazing areas in less harsh

environments (El Aich et al., 1995).

Damage done on forests can not be attributed totally

to small ruminants for many reasons. Firstly, there is

an increased demand for ®rewood for local and urban

A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287 279

consumption, which puts a lot of pressure on forests.

Secondly, the land status usually makes the presence

of the forest services less active on lands managed for

decades by farmers. Thirdly, clearcutting for crop

cultivation, because agricultural activities are

expanded on the most productive range lands, results

in overstocking of forests when converted to grazing

lands by thinning dense forests.

4.3. Overgrazing as the major cause of degradation

4.3.1. Extend of overgrazing

Overgrazing is the utilization of rangelands beyond

the limits of their capacity. Utilization is inappropriate

with respect to season and/or the duration of grazing.

Overgrazing results in rangeland degradation. Effects

of uncontrolled livestock grazing, accelerated with

those of droughts, initiate the process of deserti®ca-

tion.

Overgrazing is occurring in areas where the pres-

sure on natural resources is high. Geographical dis-

tribution of lands with degree of deserti®cation

hazards (BSTID, 1990) shows that lands with high

risk of deserti®cation are located in Asia, Australia

and Africa. In Africa, the Sahel countries are the most

exposed to deserti®cation hazard.

4.3.2. Causes of overgrazing

Overgrazing resulted from the long history of mis-

use of range land resources. The misuse is caused by

overstocking, usually associated with reduction in

grazing areas, inappropriate use of range land

resources with respect to grazing season, reduction

in grazing areas and inappropriate distribution of

animals.

4.4. Overstocking and reduction of pastures

Livestock numbers have increased in arid zones at

rates close to demographic ones. In African arid zones,

Le HoueÂrou and Gillet (1985) reported that livestock

numbers indicated an average increase of 75% with

great variations among African counties. Increased

livestock populations in tropical and subtropical coun-

tries overstocked range lands such as in Zimbabwe

where livestock populations increased by 119%

between 1964 and 1977. During the last 30 years,

stocking rates are estimated to be 3±8 times and 10±15

times higher than recommended (BSTID, 1990). Of

the 1000 km2 annual expansion of the desert in China,

18% resulted from the overstocking (Le HoueÂrou,

1992). The same author reported the following con-

tributions of overgrazing to deserti®cation: 26%, 65%

and 62% for North Africa, Sahel region and the arid

zones of Middle Asia.

Concentration of animals in fragile zones increased

the impact of overgrazing such as in Algeria, where

74% of the Algerian livestock population is kept on

range lands and in the steppe, and in Syria where about

75% of the sheep are located in areas with less than

250 mm rain, mainly steppe and range lands (Trea-

cher, 1990). A secondary factor that explains the

increase in small ruminant populations is the high

proportion of rural population that generates a surplus

of labor, which usually needs an economic activity

that does not require land ownership. Concentration of

animals in smaller areas for longer periods through

sedentarisation results in overgrazing. Establishment

of water points without any grazing controls increases

the grazing pressure on range lands previously used

infrequently. Lack of water for small ruminants in

some arid range lands limits their use to de®nite

periods of the year and increases pressure on others

when water is available. To cope with this problem of

shortage of water, small ruminant producers devel-

oped different strategies. In some instances, small

ruminant producers water their animals every other

day (El Aich et al., 1991). For other small ruminant

producers, the widespread availability of trucks facil-

itates the transport of animals and water to range lands

previously used infrequently (Morocco, Saudi Ara-

bia). Water can be sold on range lands during seasons

of shortage such as in the Middle Atlas of Morocco

where trucks are getting specialized in the trade of

water to sheep producers using some high mountain

range lands during the summer. Inappropriate timing

of utilization of ranges resources has caused similar

effects to overgrazing since it reduced plant vigor and

reproduction. Decisions on grazing never take into

consideration range readiness or plants reproduction.

Grazing on most common use range lands starts right

after physical barriers are gone, i.e. frost, cold, snow.

Overstocking is also caused by socio-economical

factors. Small ruminants represent for the producers

not only livelihood, but a means of accumulating

capital, insurance and prestige as well. Therefore,

280 A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287

prosperous families are reluctant to reduce their stock.

Offered prices to pastoralists are usually too low to

encourage them to sell during times of abundance

which keep the large numbers of animals on range

lands. Collective land tenure, as discussed earlier, put

no incentive to grazing controls and leads to over-

stocking. Ownership of livestock is individual as

opposed to the collective land status. This contrast

between the collective ownership of grazing resources

and the individual ownership of livestock results in an

absence of maintenance of grazing areas and favors

the uncontrolled competition for limited grazing

resources. Expanding dry land agriculture, as dis-

cussed earlier, reduces the size of grazing areas and

puts more pressure on the remaining range lands.

Overgrazing is not only a concern in arid and semi-

arid environments. Britain has chosen to be the only

EU country to cross-comply the main EU livestock

support payments with environmental protection by

enforcement of a de®nition of overgrazing, `̀ grazing

land with livestock in such numbers as adversely to

affect the growth, quality and species composition of

vegetation (other than vegetation normally grazed to

destruction) on that land to a signi®cant degree'' (UK

Agriculture Departments, 1997).

By and large, however, concerns in Britain are

related to changes in the species make-up of habitats

and the conversion via grazing of managed semi-

natural habitats.

4.5. Inappropriate distribution of animals

Overall stocking rates, especially on rangeland or

mountain grazing land may not be the cause of over-

grazing problems. Rather it may be the concentration

of animals in certain areas which can create a problem.

The main factors that affect animal distribution are

proximity to supplementary feeding or watering

points, proximity to areas of better grazing quality,

and shepherding. Supplementary feeding will modify

the diurnal pattern of grazing by sheep and lead to

changes in grazing behavior (Waterhouse, 1997).

Grazing will be mostly close to feeding points, leading

to increased excreta returns and cumulative vegetation

changes. This may further concentrate the grazing of

small ruminants. Vegetation preferred by livestock

will also have a similar effect, unless access is con-

trolled to improved pastures and semi-natural areas

near them will be heavily grazed. The problem

increases as the margin between modi®ed vegetation

and ecologically preferred vegetation is likely to be

grazed heaviest and the area modi®ed by grazing near

feeding and watering points slowly increases. Con-

versely, this concentration at certain points can lead to

under-grazing at others. This can lead to changes in

grazing quality, such as through build-up in shrubs,

which subsequently force the animals more heavily

onto the overgrazed areas. The ideal prevention of

these problems is to use shepherds to disperse the

¯ocks more evenly over the grazing area. However, as

described above, the reduced availability of shep-

herds, especially those willing to live away from

the villages is a major problem. Other social and

political changes such as the establishment of new

national borders and the drilling of boreholes have led

to concentrations of formerly nomadic herdsmen and

their livestock.

4.5.1. Consequences of overgrazing

Overgrazing of rangelands has reduced their pro-

duction and caused shifts from predominately high

quality perennial plants such as perennial grasses and

legumes to low grazing value species such as annuals,

and thus reducing overall conservation value. Con-

tinued high animal density accelerates the removal of

palatable species and the lack of competition permits

the growth of species by affecting their vigor and

reducing their opportunity of natural reseeding.

Decreases in palatable species allow woody shrubs

to increase in density as a result of overstocking.

Increased numbers and densities of small ruminants

have resulted in a reduction in range land carrying

capacity. In Algeria between 1971 and 1985, the

carrying capacity was reduced from 0.18 to 0.09

ewe/ha. In Iran, heavy overstocking is estimated to

exceed carrying capacity four times (BSTID, 1990).

As a result of the reduction in carrying capacity, small

ruminants depend on external feed resources. In

Algeria, as is the case in most tropical and subtropical

countries, range lands contribute little to meet small

ruminant requirements, less than 20% while the

remaining feed is bought as barley grain, straw and

bran (Boutonnet, 1989). The use of external sources of

feed (barley), usually subsidized, enhances the

increase in small ruminant numbers, because meat

price is variable and free, while that of feed is ®xed by

A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287 281

government with a price ratio of 1/12 to 1/15 (Bou-

tonnet, 1989; Bourbouze, 1996).

Increasing grazing pressure increases the propor-

tion of bare soil and more important reduces the

amount of vegetation litter directly linked to soil

fertility. Increased demand for grazing in common

access land leads to progressive erosion and decreased

soil fertility, lowering of water tables and loss of

biodiversity. Higher grazing intensities result also in

soil compaction which is responsible for higher runoff

and less in®ltration.

4.5.2. Environmental benefits of managed

overgrazing

Undergrazing might be as harmful as overgrazing.

In areas such as Southern France where forests,

maquis, and garrigue have not been browsed recently,

there has been a buildup of fuel and a serious increase

in ®re hazards that resulted in a sharp rise in the cost of

®re prevention. Browsing by goats and wildlife is an

ef®cient and cheap way to prevent ®re (Le HoueÂrou,

1981). Similar trends to woodland in the Lozere region

of France or the Iberian peninsula were reported with

reductions in stocking (Egdell and Dixon, 1996).

In some instances, sheep and goats can be used

intensively and wisely to control brush, to upgrade the

environment and to help prevent grassland and forest

®res. In many areas such as the wet tropics (Sahel and

Sudan regions of Africa and the East African bush),

chaparral area of California, oak brushlands of Texas

and Oklahoma and the matorral of the Northern shore

of the Mediterranean (Corsica and Sardinia), the use of

goats would likely be more effective and economical

for the control of many brush species than chemical or

mechanical methods, because goats eat large amounts

of brush browse in their diet. Goat farming has been

widely used in Texas to control large range shrubs

including oaks and mesquite (Valentine, 1971). Other

studies reported from California (Davis et al., 1975;

Green et al., 1978; Sidahmed et al., 1978) and South

Africa (Du Toi, 1972) the effectiveness of goats under

heavy stocking rates to control shrub growth. Goat

¯ocks were recommended to use against the invasion

of forests in the PyreÂneÂes mountains by the Erica

arborea and Cistus sp. maquis (Bartello et al., 1987).

In the Mediterranean forests, grazing the herbac-

eous layer by small ruminants has been effective in

preventing ®res (Thivaut and Prevost, 1986). After

shrub removal, grazing by small ruminants enhances

the control of shrub regrowth. Figures of ®re frequen-

cies reported by Le HoueÂrou (1980) for some Med-

iterranean countries indicated low numbers for

countries where forests are grazed, especially those

of the southern shore of the Mediterranean.

In addition to the feed these fodder shrubs provide,

they would not present any pollution problem while

ensuring control of invading shrubs at low cost. It has

been reported that goats can be economically used in

brush control programs which resulted in improved

vegetation composition for cattle and sheep. Follow-

ing an economic analysis of 15 ranches, Magee (1957)

concluded that, in addition to preventing brush regen-

eration, goats paid for the costs of clearing.

4.6. Pollution

According to Stanners and Bordeau (1995), the

more important aspects of agricultural practices that

impact on the environment are water pollution, decline

of soil quality, loss of biodiversity and landscape

change. In terms of pollution to water, small ruminants

can pose a threat through their own waste products,

through pollution ¯owing from stored feeds, such as

silage, and through chemicals used in health treat-

ment. The ®rst two of these problems occur greatest in

more intensive systems and where animal concentra-

tions are high.

However, small ruminants pose a much less severe

pollution threat than cattle, pigs and poultry. A recent

study in Britain showed that whilst sheep production is

a major enterprise in Britain (on 36% of farms, Ash-

worth et al., 1997), the numbers of pollution incidents

involving sheep are extremely small compared to

those from dairy and beef cattle (Entec, 1995). Small

ruminants tend to be found in low input extensive

systems, and the potential to produce large concentra-

tions of ef¯uent from animal waste and feed stores is

low. Levels of nitrogen and phosphorus in water are of

concern mainly from agriculture. In certain areas of

Europe, 80% of the nitrogen load and 20±40% of the

phosphorus load is believed to come from agriculture

(Stanners and Bordeau, 1995). Such problems are

worst in regions with highly intensive livestock agri-

culture, e.g. the Netherlands. Small ruminant systems

tend to be low or nil users of arti®cial fertilizer and can

be exporters of animal manure (Treacher, personal

282 A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287

communication). Even in intensive sheep systems, the

levels of fertilizer used are relatively low. Surveys

carried in Britain by the Meat and Livestock Commis-

sion demonstrate that levels of nitrogenous fertilizer

used in intensive British sheep systems are decreasing.

In 1995, the average level of application in upland

¯ocks was 35 kg N/ha (MLC, 1996) compared to

86 kg N/ha in 1979 (MLC, 1981). This decrease is

undoubtedly linked to the increase in use of clover-

rich swards. However as Sibbald and Hutchings

(1994) point out, the level of nitrate leaching from

clover-rich swards is unlikely to be less than from

conventionally fertilized low input swards.

Speci®c problems associated with health care in

small ruminants may occur from

1. the avermectin group of compounds when used

orally for parasite control, which will lead to

insecticidal dung that has a signi®cant impact on

coprophageous fauna and the associated food

chain (McCracken and Foster, 1993),

2. sheep dips that are toxic, and waste dips entering

water courses may create problems. Synthetic pyr-

ethroids are much more toxic to aquatic life than

the organo-phosphorus compounds they are repla-

cing and can cause severe local environmental

incidents when the dip reaches water courses.

Developing countries are not necessarily any more

at risk of accumulating pollutants in the food chain

than developed countries, but the way pollutants

accumulate and impact on humans could be very

different. The numbers of steps between production

and consumption are much fewer in developing than

developed countries. Therefore, in areas of chemical

or other contamination, to what extent do small rumi-

nants act as ®lters to decontaminate a contaminated

food source, to what extent do chemicals and other

contaminants accumulate in the food chain, to what

extent do sheep and goats mediate entry of contami-

nants into the food chain, and to what extent do they

contribute contaminants to the food chain?

A most obvious example is a petrol contaminated

area like Kuwait or nucleotide contaminated area like

sections of Khazakstan (Rittenhouse personal com-

munication).

In conclusion, small ruminant systems, even when

run relatively intensively, may utilize less fertilizer,

use less energy demanding products and produce less

direct pollution than equivalent large ruminant based

systems.

5. Environmental methodological and researchissues

5.1. Environmental methodological issues

Many of the debates associating small ruminants

and environmental impact have very little hard infor-

mation available for this debate. One of the key issues

associated with small ruminants and environmental

conservation is that whilst it is relatively easy to assess

the impact of the environment upon the animals, it is

much less easy to do so for the impact of the animals

on the environment. Many impacts are small or slow to

take place or indeed the impact is not direct (e.g. the

removal of animal dung impacts on those birds that

feed on invertebrates that eat animal dung). Measuring

vegetation state and change is perhaps the most

important example of where understanding and site

speci®c management could be improved if there was

good information available on the true dynamic

changes occurring to the vegetation. Too often man-

agement decisions are based on a snap-shot of vegeta-

tion state as it stands today rather than knowledge of

what it used to be like. There are therefore important

needs to ®nd indicators of change by looking at current

plant community structure and at plant morphology

(McDonald, 1997). In Britain, some attempts are

being made to characterize the intensity of grazing

by sheep (too much, too little or sustainable) by

examining heather morphology and state. Further-

more this plant also provides an example of how

modeling of foraging behavior and intake (Armstrong

et al., 1997) can be used to predict future impact and

thereby remove some of the guesswork from manage-

ment planning. Even this model requires good infor-

mation on the land areas of different vegetation and its

state and not the least the number of animals using the

area. There is still a very considerable lack of knowl-

edge and understanding as to how management prac-

tices in¯uence environmental conservation, but often

there is a lack of information merely to describe

accurately the current state of vegetation.

This is also true in terms of the other elements of

environmental impact, such as pollution, and leaching

A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287 283

of nutrients from soils where, although it can be

suggested that small ruminant systems are less pro-

blematic than other land uses, the precise understand-

ing is still limited and there are not enough hard data

available in how small ruminants in¯uence the wider

ecosystem.

At an ecosystem level, a holistic approach has been

proposed by Wetstein et al. (1996) to assess the

environmental impact of livestock. They suggested

the pressure state response model (PRS) de®ned by the

OECD (1993) as a tool to structure environmental

indicators. The model assumes the interaction

between human activity pressures, that exert a force

on the environmental state, which lead to a change in

the ecosystem and the use of natural resource

responses.

5.2. Environmental research issues

The state of knowledge related to the impact of

small ruminants on the environment is still partial and

unbalanced. Most of the work has been done on the

characterization of the vegetation (mapping and pro-

duction). This knowledge is insuf®cient to solve ques-

tions related to the dynamics of grazed areas and their

conservation. Another body of knowledge dealing

with traditional practices and skills for managing

the use of resources has been ignored until recently.

A number of problems arise in considering current

and future research needs. Firstly, how can current

research ®ndings be applied for conservation pur-

poses? Much of recent research in small ruminants

has been driven from an agricultural perspective. Can

these data be used when environmental objectives take

priority. Clearly, there is considerable scope for this,

but only within the constraints and parameters inves-

tigated in the research. Also much research is incom-

plete, is likely to be site speci®c and has not been

substantiated by other independent work. Back in the

80s, Le HoueÂrou and Gillet (1985) were wondering,

why there were so few conservation projects imple-

mented in Africa? These authors provided as answer

the dif®culty of the conservation projects because of

the social and political context.

A second problem is that whilst it has been accepted

to include scienti®c knowledge and understanding in

planning management changes to achieve agricultural

goals, it is more dif®cult to incorporate ecological

knowledge into the decision making process. Firstly,

this knowledge may not be available to the land

manager and secondly, it poses a more complex

problem to solve if there are multiple objectives

required.

Finally, whilst researchers have proved very suc-

cessful in characterizing the present (such as current

productivity of grassland or its current species diver-

sity), there is considerable lack of good information on

which to plan the future so that current problems can

begin to be solved. Unfortunately, there is less con-

®dence in predicting the future dynamics of vegetation

under different management regimes. Where models

have been constructed, time is required to determine

whether the predictions come true.

6. Environmental system stability

There are many examples of how current ecosys-

tems, and habitats within them, are degrading due to

the impact of changes in small ruminant systems.

Above, the range of changes in the ways that systems

are managed leading to imbalances has been

described. Better integration of small ruminants into

systems with other enterprises is one means by which

any negative impacts could be reduced and how

environmental quality could be achieved. The low

input cereal systems found in the steppe and dehesa

regions of Spain are particularly useful examples of

where the grazing by sheep and goats of the stubble

and the fallow is extremely useful when it is integrated

carefully. Seeds are spread, cover of the typical annual

plants is achieved without build-up of shrubs and the

ruminants provide useful carrion for raptor species.

Without this integrated grazing, the system becomes

environmentally less successful and the stability of the

system is reduced.

Where small ruminants are the major production

system, then there is a need to understand all the ways

in which the livestock system interacts with the envir-

onment so that the most appropriate management plan

can be devised bearing in mind the need to meet social,

economic and environmental objectives.

Certainly, the whole ecosystem can be put at risk

where small ruminant systems are removed. As

described above, where grazing is removed there

can be shrub encroachment, losing elements of land-

284 A.E. Aich, A. Waterhouse / Small Ruminant Research 34 (1999) 271±287

scape and biodiversity such as alpine or sub-alpine

meadows. Even more sudden, the build-up of shrub in

woodland will increase risk of damaging ®res as

described above. In many mountain areas, these severe

®res will lead to increased erosion risk. Thus, loss of

what is perceived as a minor component of the whole

management system can lead to catastrophic impacts.

Where the bene®ts of grazing are recognized, small

ruminant systems are valued and integrity of the

ecosystem is maintained.

Small ruminants therefore play a key role in main-

taining habitats and landscapes in their current state,

often achieved via centuries of livestock keeping.

Problems of under- and over-grazing need to be

recognized and dealt with so that environmental

degradation can be prevented by appreciation that

careful management of the small ruminant is the main

means by which the chosen environmental state can be

achieved.

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