Peri-Urban Ecosystems and Societies: Transitional Zones and Contrasting

Values

Ian Douglas

Introduction

Peri-urban areas are the transition zone, or interaction zone, where urban and rural activities are juxtaposed, and landscape features are subject to rapid modifications, induced by human activities. These critical areas of land cover change. leading to uansformations in the hydrological, ecological, geo- morphoIogica1 and socio-economic systems, are often neglected by both rural and urban administrations. However, as cities d e d o p , much of their growth is located in such areas. Many peri-urban activities move outwards as the c i~y grows; other activities and land uses become incorporated w i t h the urban

1 fabric. Peri-urban areas are mosaics of temporary, new residents and activities mingled with longstandmg land uses, incIuding farms, villages, quarries and / forest patches.

Peri-urban areas receive two flows of migrants creating wide variations in wealth and social status: urban people seelung a more rurd lifestyle or cheawer accommodation, and poorer rurd people searching for woik and heher chances for their chrldren. Thepen-urban areas of many cities h d ~ t h high vdue middle-class properties and poor in-migrant squatter settjegents a few h i n d x m e t r a - a p s Located among--these uses wiU be market gardening, sand and gravd workings and brick day pits, oil refineries, petrochmicd piants, power stations, tanneries, airports and dvided hawavs.

- , Peri-urban areas thus come to-be valued in hfferent ways by diverse groups. These values vary between continents, nations and regions. They indude:

for the poor: places where it is easier to build shelters and to occupy land for agriculture; for rirdustry: sources of materials essential for urban life: water, brick-clays, sand and gravel, limestone, fuelwood and timber;

for the middle c h s : a place for houses in a rural setting, with goE courses and other recreational facilities; for h l government: sites for landfills, waste dumps, peripheraI freeways, airports or noisy and toxic industries; fbr coasmatiotsisbs: the site of valuable protected areas, forested hills, preserved woodlands, important wetlands or mangroves, and major coastal ecosystems; fOr education and humas well-bei~lg: the place of first contact that urban peaple have with major areas of natural vegetation and biodiversity.

The task of this chapter is to attempt a developing areas perspective of our scimtific understanding of these diverse peri-urban environments, inhcating the key issues of peri-urban areas seen by scholars in Lacin America, Africa and Asia. It reports evidence collected in the Peri-Urban Environmental Change Project (PU-ECH) of the Scientific C o d n e e on Problems of che Environment (SCOPE) of the International Council for Science (ICSU). Established by ICSU in 1969, SCOPE undertakes assesrnents of what we know about key, merging environmental issue and identijies the most impor- tant research priorities for future wo~k on hose issues. Forty national academies of science (including The Royal Society), 26 scien~fic unions (including the International Geographical Union) and several other ICSU i n t e r d i ~ c i p h a r ~ bodies, such as the International Human Dimensions Programme (EDP), am members of SCOPE. Their representatives elect the SCOPE Executive and approve SCOPE projects. The projects range from the impam of d t q deveIopment of nuclear sites to endocrine disrupters. They are usually undertaken in partnershp with scientific unions, other ICSU committees or bo&es, such as the United Nations Educational, Scientific and Cultural Organization (UNESCO) and the United Nations Environment Programme (UNEP). Pro~ects are put forward by members, by the Executive or by United Nations (UN) bodies. On approval by the United Nations General Assembly, a project scientific advisory committee, normally with a member from each continent, is appointed. The PU-ECH sciendic committee has members from Argentina, Canada, China, Italy, the UK, Zambia and UNESCO. It has held meetings in Argentina, China, Labanon, Nigeria and Zambia, whch between them have brought together some 200 scientists from 65 dtfferent countries. The sections of this chapter d a t e to the seven themes of PU-ECH. Contributions from the meaings are identified by the parrici- pant's name and the meeting (for example, PU-ECH Abuja).

The need for an applied science view

Managing peri-urban areas requires an integrated view of a l l the activities and land uses occurring within them. Much research, however, tends to be thematic, focusing on indrvidud important sectors of activity - sectors which inevitably impinge on other activities, such as the effects of atmospheric pollu- tants on peri-urban agricultural crops. If the perspective of ecosystem dynamics is adopted and human interventions are seen as perturbations of

20 The PePd-Urban Inte&ce r'eri-Urban Emsy~tems and Societies 21

ecosystems, peri-urLq environmend c h a n ~ e becomes part of the d g u b i o g e o c h e m i c d ~ c y & ~ What makes the peri-urban envi- ronment so intereting is the complexity of political, economic and social 1

b drivers impacting locally on those biogeochemid cydes and the resulting -

outcomes for the h d t h , well-being and economic survival of people in peri- urban communities. Ecosystem dynamics can be wed to link decisions and actions by one agency to outcomes and consequences for communities and

) individuals. b~ this way, we can docate r ~ ~ o n s i b h t i e s , identify =iron- mental injustices and assess theconsequences, both on-site and off-site of -. planned futur~ ~eri-wbm changes, - --_

htegrated management of a contested space, where the off-site impacts of Iand uses and activities are at 1-t as important as those w i h the changing land unit, thus becomes a challenge to all the environmental, geographical and planning disciplines. It is as complex as delivering Locd Agenda 21 since it involves reconuling the diverse special interests of different sectors and communities to acheve agreed shared goals by developing understanding between politicians, business, officials, civd society organizations and the public. The first step in this is to achieve a shared awareness of the different interests and concerns in peri-urban environments. This begins by under- standing the nature and rate of Iand-use/land cover change, -. - -

The nature and rates of land cover/land-use change in developing area peri-urban zones

i The poor and the middle class d e c t peri-urban land use &erenrIy. Low-density ,$ middle-class urban sprawl - the occupation of former rural land by Iow-rise

/ developments - is becoming a major issue in developing countries. With prob- 1 ably 300 mdhon middle-daas people each in In& and China, peri-urban

housing estates are occupying farm land and increasing food prices for rich and poor alike. Particularly spectacular urban s p m d occurs in rhe Pearl River Delta (LI and Yeh, 2004) and around Shanghai and Beijing, the bdt-up area of the latter expan& by 25 per cent between 1992 and 2002 (Li et d, 2005).

The European Commission (EC) Monitoring Land UsdCover Dynamics (MOLAND) projecr on urban and regional land-use change Has been applied to several cities in Africa. Defining the urban system as the portion of h d covered with continuous artificial surfaces, including a buffer of the same area around them, MOLAND develops inhcators of change in areas of peri-urban agriculture and natural vegemtion (Barredo and Demichelli, 2003). Using information ranging from early maps to the detad of IKONOS and specidy flown aerial digital photography {ADP), the evolution and outward shift of peri-urban areas can be established. Good ground-truthing is particularly important. For example, work in Kurnasi, Ghana, found that digital methods tended to classify sand extraction (quarrying) areas - a common peri-urban land use around the city - as built environment, thus exaggerating the land area occupied by settlements (Pender et d, 1999). Peri-urban expansion has been modelled by examining how individual grid cells of land around citia wiIl

I

respond to the factors driving change, such as land attributes, land prices and proximity to commuter highways (Cifaldi et al, 2004). At the PU-ECH Abuja meeting, C. L. Odimuko emphasized the need for a nationd land information system in Nigeria with organized and standardized data on secure tenure, title,

I deeds and structures, and the Honorable Levi Ogulke explained the use of spatial information systems for tracking urban growth, in-migration, spread of housing and illegal occupation of land.

Peri-urban land coverlland-use changes and their origins in processes of migration, poverty and providing basic

human needs

Migration forced by war, civil conflict or environmental degradation often : increases peri-urban populations. The prolonged cid war in Mozambique . caused approximately 6 million people to move to pen-urban areas where resource degradation is now an increasing problem. More than 70 per cent of thae people are 'ultra-poor', unable to afford h e minimum daily nutritional intake of food. This situation occurs in many African cities, where the urban_ poorofmdewte 60-70 per cent of their incomes to purchasing food (Tanya Bowyer-Bower, PU-ECH Shahen) . In the M d a Saba peri-urban settlement of Nairobi, 68 per cent of the households in this informal settlement practise- so-me kind of f a and can earn up to US$6.5 ~a week They have no secu-

I rity of tenure and rely on being able to break into the dilapidated town sewer pipe ~o divert water to their pbts at l a s t once a week (Sammy Ngoke, PU- ECH Shenzhen). Some municipal officials consider urban agriculture to be a

I backward step (Eduardo Spiaggi, PU-ECH Rosario). Tenure regularization on ptri-urban land and policies linking peri-urban agriculture to food security are needed (Shingirayi Mushamba, PU-ECH Lusaka).

Despite its contribution to supplying immedlate food needs, the effective- ness of urban agriculture is being questioned (Lynch et al, 2001) (see Table 2.1). Many wornen food producers suffer stress and poor health due to their insecurity, risk of eviction and pollution of crops (Rain, 1997). Large numbers of people grow their own food around Amman, Jordan; but they use so much fertilizer that adjacent asLufers are affected. Poor borne gardeners suffer from severe water shortages and are unable to buy extra water or to purchase stor- age tanks for rainwater harvesting (Kharnis Raddad, SCOPE Beimt).

Consequences of land cover/land-use changes as induced by materials flows for shelter, manufacturing,

infrastructure and transportation: Accumulation of the urban 'stock'

Cities have always exploited the local forests, clays, sands, graveIs and rocks of their immediate hinterland to build shelter and infrastructure. W h h timber is

22 The PenLUrban Ifiterface

Table 2.1 The berrefdts und problem of peri-urban agrimkure

Benefits Problems

Vital or supplementary food source Seasonal water shortages for irrigation Ensuring availabiliy of fresh vegetables Health impacts of contaminated waste Food waste provides livestock feed Air pollution impacts on crop yields Environmental bendi i (for example, f f d Contamination of crop foliage

basins; carbon sequestration; urban heat Pollution of aquifers by contaminated island modiication) irrigation water

Employment for the jobless Irrigation water malaria riih Survival strategy for low-income residents Insecurity of agricultural land tenure Use of urban wastes as fertilizers Potential conflict with other land uses

Often administratively an 'illegal' or inappropriate land use

Real impact on overall urban food suppty may be limited

Relative advantages of peri-urban or rural production undear

S o u m adapted from Lynch et al, 2001; Agrawal et al, 2W3; Afrane et al, 2004

now traded globally, materials for brick and concrete manufacture continue to be sourced dose to cities, often at the expense of important land uses, espe- cially peri-urban agriculture and horticulture, as around Aligarh City, India (Singh and Asgher, 2005). Clay worlung and brick manufacture degrade both land and the environment, forcing farmers to shift their land from agricultural to non-agricultural uses. Around Aligarh, farmers and agricdturd workers are now contractors, labourers or dnvers, or even brick kiln owners. Development and prosperity in these villages have increased; but the government and envi- ronmentalists are concerned about the serious impacts of brick kilns on land and the environment. Alternative mareriaIs, such as s h e and alkahe soils, red so& and fly ash mixed with inferior-qu&ty clay, codd be used instead of ferule agricdtural soils.

Around the Argentine city of Mar deI Plata, much land has been disturbed by clay extraction for brick-making, with illegal day working in many placer. Use of the hols left behind ss landfills leads to many problems, particularly groundwater pollution. In many places above the fractured ortho-quartzite bedrock, seepage from the landfill has caused severe nitrate contamination, affecting many wells beneath the city (Luis del fio, PU-ECH Rosario).

Many consequences of minerals extraction arose in hscussion at PU-ECH Beirut. Deep quarries some 3Okm west of Cairo and former ~hosphate mines outside Amman, Jordan, are used for landfill. Although quarrying on Mount Lebanon i s now banned, little rehabilitation of the extensive unregulated quar- rying that took place during the Lebanese war has transpired. Coastal land reclamation is occurring in Lebanon at many sites, from Beirut northwards to Tabarja. Widespread beach mining - the iIlegal extraction of sand from the

2eri-Urban Ecosystem and Societies 23

foreshore - in Lebanon affects coastal erosion. Beach ownership is now a po l i t - ically significant peri-urban issue, with access to many parts of the coast being cut of£ by fences and claims of private ownership.

Air and water pollution and soil and land contamination in peri-urban areas, and their health and ecosystem impacts

Peri-~rban ecosystems involve great modifications of natural biogeochemical flows. Chemical transformations associated with manufacturing, food process- ing and urban building lead to the release of heavy mads, plant nutrients and organic compounds t o the atmosphere and to soil and water bodies that in excessive concentrations may cause harm to living organisms. Poor sanitation and drainage compound these problems. Many peri-urban residents cope with high local pollution levels every day of their lives.

Around Karachi, Pakistan, water supplies and waste management cannot cope with haphazard urban growth, especlaUy in peripheral squatter settle- ments. However, the Orangi township has overcome some of the issues through a series of public-private partnerships developed after complex social factors, includrng lack of init iative, local politics and disputed payments to tanker contractors, led to water riots. Tanks built by the military force, the Pakistan Rangers, filled by commercial contractors (Ahmed and Sohail, 2003) and managed by the mosque and neighbourhood local elder committees, are

, regarded by local peopIe as a temporary arrangement und the sustainable long-term solution of a piped supply arrives.

Throughout the world, some municipal sewer systems are overloaded, orhers have combined sewers with storm oveddows to rivers, while some Iack maintenance and Iak and others are deliberately broken to extract irrigation water, exposing farmers to dysentery and cholera risks from faecal bacteria and worm infestation (Bradford et al, 2003). Nevertheless, urban wastewater is used for agriculture in Kumasi, Ghana, through collaboration with local 1

communit i~ to control impacts on watercoursa by careful latrine siting. Industrial effluents pose bigger problems, with instances of textile d y s being

I thrown directly into channels and municipal trucks dumping sewage, which then flows directly into channels (Kwasi Nsiah-Gyabaah, Duncan McGregor and David Simon, PU-ECH Abuja).

Air pollution affects ddferent crops in various ways (Agrawal et al, 2003; Wahid et al, 2001). The Mung bean, for example, is sensitive to suIphur &oxide ( S G ) which may cause a 56.5 per cent reduction in yield. SO2 is a primary pollutant, but secondary pollutants and particulate also need to be considered, especially the heavy metals that fall on crops as aerial deposition and which can affect food safety (Fiona Marshall, PU-ECH Shenzhen). Copper and S Q pollution from the Mulfira, Zambia, smelter affects soils, vegetation and probably human health in areas immediately downwind (Everisto Kapungwe and John Volk, PU-ECH Lusaka). Acid rain has seriously &acted forests and crops around Guangzhou, China Uin Lahua, PU-ECH Shezhen).

24 The Perd- Urban Interface

h i - u r b a n communities around Kumasi, Ghana, successfully experimented with household-composiing strategies to improve sanitation and provide organic fertiljzer (Kwasi NsiA-Gyabaah, Duncan McGregor and David Simon,

I PU-ECH Abuja; see also Chapter 16 in this voIume). Such fertilizers (and bio- [fuels) can cost lers than landfi, provided the health risks to waste hmdlen, farmers and consumers are managed (Cornish et al, 1999). Mitigation methods indude minimizing heavy metals in compost by separating urban market waste from industrial waste; reducing or eliminating gastrointestinal mfection trans- mission risks by thermophihc composting; extended storage and/or drying; applying untreated excreta two months before sowing cereal crops, although farm workers are still exposed to worm eggs; care in waste and compost h m h g (Vasquez et aI, 2002). Nevertheless, the off-site impacts of both compost and waste nutrients on s o h and water bodies need attention.

Impacts of water use and hydrological and aquatic ecosystem transformation, and their consequences

Many peri-urban people depend on easily contaminated shdow wells d o s e water Iwels and qual~ty reflect the land-use rransformauons around them. Groundwater 1wek around Beijing fell 15m to 25m between 1950 and 2000. A ten-year surge in vegetable and livestock production involving annual fertiher applications of up to lOOOkg per hectare led to 170 square kdometres of Beijing municipality having excessive groundwater nitrate concentrations (Wolf et al, 2003). The changing diet of the wedher urban population thus feeds back into the urban and peri-urban water supply. Similar water poIIution issues arise throughout developing peri-urban areas. Poor sanitation and a fissure rock substrate cause springs in the peri-urban South Lunzu township in Blantyre, Malawi, to have between 730 and 9500 faecal colifoms per lOOml, whde wells average 11,000 and the Lunzu River 18,500 compared with h e township borehole average of 30 (Lobila Palamuleni, PU-ECH Lusaka). The European Union (EU) h t of 2000 faecal coliforms per I h I for bathing water indicates the seriousness of this contamination.

Peri-urban flooding, inadequate stom-warer drainage and poor waste management (Parkinson, 2003) increase health hazards such as mosquito breeding grounds. Poor storm drainage leads househoiders to use sandbags to protect tAeir properties, pushing runoff water on to other people's land (as observed at Mandevu, Lusaka during PU-ECH fiddwork).

The rapid deterioration of aquatic Me in many Aslan, African and South American urban rivers is well illustrated by endocrine disrupters from phar- maceuticals that pass through the urban sanitation and drainage system to rivers and into the food chain, causing changes in the sexual balance of fishes and possibly creating hazards for people who eat such fish (Alejandro Oliva, PU-ECH Rosariol. Such complex chains of caus&ty linking human behaviour ro environmental change and then, in turn, affecting human health emphasize the need to understand the dynamics of p i -urban ecosystems and to endeav- our to maintain and restore many natural ecosystem attributes close to cities.

2i-Urban Eco.rystems and Societies 25

Ecology and biodiversity of urban areas: Resilience and response, particularly in stressed environments

Invasive species introduced by urban activities affect the ecosystem services provided by peri-urban green spaces, including local climate mo&cation, reducing air pollution, sequestering carbon dioxide and storm runoff reduc- tion (Li et al, 2005). However, invasive species frequently increase the biodiversity of pen-urban areas. S h a Talhouke (PU-ECH Beirut) found 441 specks in 26 plots in densely ~opulated coastal Lebanon, where abandoned agricultud land was richer in biodiversity than ocher land.

From Beijing to Szo Pado, peri-urban green belts face challenges from new recreation provision and transportation infrastructure. China opened its first golf course in 1984, but had 200 by 2004 and plans for 1000 more. Tree planting is also expanding, urban forestry providing both economic and envi- ronmental benefits for developing area cities (Su and Profous, 1993). Beijing is crating three large-scale tree belts by 2006, including a 240 square kilometre geen belt between the third and fourth ring roads. The Siio Pado City Green Belt Biosphere Reserve (Rodrigo Victor and Joaquim de Britto Costa Nao, PU-ECH Rosario) contains varied habitats, from coastal and ~nland moist forests to mangroves, c m d o (savanna), wetlands and urban areas (Victor et al, - 2004).

Abandoned peri-urban industrial land offers a diversity of ecological habitats often having apparently naturd vegetation. Derelict land restoration is a growing issue in tropical countries. Even rudimentary restoration of trop- ical formerly mined land increases bird numbers and diversity (Passell, 2000); is better than abandoned mine sites; and brings local community benefits, reducing dust, providing recreation and, eventually, facilitating reuse for agri- ; c u h r c or urban development. Derelict land restoration in Hong Kong shows ' heavy metals, and landfill gases affecting plant regrowth and soil subsidence risks over restored but improperly managed landfills (Wong Ming, PU-ECH 1 Shenzhen) .

The expansion of cities exposes both humans and wildlife to new pathogens and vectors. Hantavirus pulmonarj syndrome, Lassa fever, cryp- tosporidiosis, Nipah virus disease, bird 'flu and plague affect people; but livestock pathogens transferred to wildlife reduce biodiversity. This peri-urban disease emergence encompasses subtle, complex and often overlooked threats (Daszak et al, 2OOO), requiring careful investigation of linkages between people, nature and biogeochemical fluxes.

Political and institutional factors in peri-urban environmental change

Political ecology helps in analysing economically, ecologically and polidcdy vulnerable peri-urban squatter and slum smlernents where landlessness and land scarcity are as critical for residents as accss to clean, safe water and sani- tation (Moff at and Finnis, 2005). Inequity in environmentaI qual~ty, shelter and

access to both natural and socia1 resources (such as education and healthcare) is rooted in social and political factors, as shown by the struggla and delays poor people face in getting water and avoiding pollution and flooding. Municipal authorities often receive the votes of the poor, but either place their needs bdow those of more powerful elites or ignore them altogether (Burra et d, 2003).

Private-seaor involvement in urban service provision produca further inequality by restricting former users' access to resources such as waste. Under public-sector management, once in the street or in municipal bins, soIid wasre belongs to municipal authorities. They are responsible for waste mllection and disposal. In India, 'rag picking' of recyclable materials and animal grazing on waste continues. Hawever, waste at private-sector dump sites is more strictly mntroued. Who gets access to waste is largely a political decision; but it should consider Both financial and socd policy objectives (Nunan, 2000). Political power also plays the key role shaping vulnerabilities to geophysical hazards in peri-urban areas (Pelling, 1999).

Top-down constm&on of 'community' groups in which leaders and members are self-selected from etablished &tes often undermines peri-urban grassroots participation in decision-makmg. New 'cornunity leaders', cIosdy associated with bcal government, often put local politicd elites in control of local community organizariom and thereby retain their control of environ- mental rehabditation projects. Even in recognized peri-urban community organizations, marginalized vulnerable individuals may be excluded from the decision-making networks of relatively high socio-economic status, house- owning business people.

The global drivers of peri-urban change, includmg structural adjustment, alter prevailing economic, social and polirical conditions, producing land-use changes in and around African cities. In Dar es Salaam, h s has meant infill and increased density, rather than further Iinear expansion along roads, and limited spatial growth to the south. Greater public transport competition and more private transport have improved access. Rapid capital accumuIarion, from trade f beralization and rent acquisition by some indviduals, has extended invesment in peri-urban m a s , but with an emphasis on short-term returns rather than larger scale production (Briggs and Mwamfupe, 2001).

Conclusions

Careful anaiysis is required to ascertain the complex social, economic and political controls of peri-urban life and environmental change. Often the influ- ence of the rich and powerful is only part of the picture. Subtle intra-group dynamics among the deprived and powerless can be significant in deciding if projects, whether locally inspired or externally supported, succeed and become sustainable. PU-ECH is recognizing how t h e e complexities relate to

; the different uses, and values of peri-urban areas. Some of the recommenda- ,b ' tions made at the different meetings are summarized as folIows:

I

Peri-Urbaa Ecoqstems and Societies 2

For the poor: 7

formal inclusion of peri-urban agriculture in the p l h g process; sustainable use of wetlands used for urban and perz-urban agriculture; increasihg (community) knowledge of peri-urban soil fertdity and ination; safe use and appkation of compost; safe agricultural production with water-quahty control and certification.

For itrdusby:

the benefits of rehabilitaring mining land; acquiring detailed field data on contaminant levels in soils, water and plants and understanhg of contaminant movement through soils and water into plants and the food chain.

For the mia2k class:

examine the peri-urban environment as an interface between the consumer system and the natural environment; promote leplation to control speculative industrial, residentid and commercial Iand development.

For bcuk governmefit:

For ~wfisewutboprists:

1 cost savings by organic waste rnanagemwt; use of advanced tools, such as geographical information s y s t m s (GIs), for city development/planning; asiess ways of alleviating the health-related impacts of air and water poilu- tion and soil and land contamination; security of land tenure and participatoty land-use planning.

development of poIicies for establishing urban biosphere reserves; evaluation of the status of urban ecosystems; use b e h a v i o d studies of people's attitudes and expectations regarding areas of natural vegetation to inform policy development.

-3'

i

For ed~ca~ebn and human well-being:

recognizing peri-urban areas as a key environmental science issue, with a specific focus on the critical gender issues relating to land use; link science to policy-makers at all levels to develop policy changes and new management structures.

Clearly, being multhnctional areas of land-use competition, peri-urban areas experience direct impacts, such as new construction, land-use changes and

28 The PencUrban Interfce

resource exploitation, together with indrect effects through land degradation, waste disposd, air poUution and water &ty deterioration. Much of the science of how individual ecological and human components and activities in peri-urban areas work is well documented. PU-ECH is taking a holistic view of this transition zone to see how problem solving, improving the qu&ty of people's lives, managing the biogeochernical consequences of change and maintaining ecosystems and bio&versiry can work together. It is aiming to produce outputs for both the scientific community and the major stakehoIders. Results are already being communicated to UN bodies. Many participants at. PU-ECH meetings are active members of local or international bodies which promote better management of peri-urban areas. By working at drfferent scales and on many fronts, PU-ECH is aiming to disseminate its findings wideIy and to intervene where it can be most effecrive. Ir is thus both a scientific and an advocacy project that may help in exchanging and stimulating ideas on inte- grated peri-urban environmental management.

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