DSpace at VNU: Assessment of ecosystem services in homegarden systems in Indonesia, Sri Lanka, and Vietnam

DSpace at VNU: Assessment of ecosystem services in homegarden systems in Indonesia, Sri Lanka, and Vietnam tài liệu, giá...

Assessment of ecosystem services in homegarden systems

in Indonesia, Sri Lanka, and Vietnam

Hideyuki Mohria,n, Shruti Lahotia, Osamu Saitoa, Anparasan Mahalingama,

Nimal Gunatillekeb, Irhamc, Van Thang Hoangd, Gamini Hitinayakee,

Kazuhiko Takeuchia,f, Srikantha Heratha

a Institute for Sustainability and Peace, United Nations University, 5-53-70 Jingumae, Shibuya, Tokyo 150-8925, Japan

b Faculty of Science, University of Peradeniya, Sri Lanka

c

Faculty of Agriculture, Gadjah Mada University, Indonesia

d

Centre for Natural Resources and Environmental Studies, Vietnam National University, Vietnam

e

Department of Crop Science, Faculty of Agriculture, University of Peradeniya, Sri Lanka

f

Integrated Research System for Sustainability Science, University of Tokyo, Japan

a r t i c l e i n f o

Article history:

Received 5 December 2012

Received in revised form

9 July 2013

Accepted 15 July 2013

Available online 22 August 2013

Keywords:

Homegarden

Ecosystem assessment

Ecosystem services

Agrodiversity

Biodiversity

a b s t r a c t

Numerous studies have been conducted on homegarden systems by researchers from different disciplines and countries, but most of them focus on ecological structure or specific ecosystem services

in a selected study area Few studies take a comprehensive look at the ecosystem services provided by homegardens, especially on a regional scale This paper shows how these homegardens are ecologically, socially, and economically diversified and how beneficial they are to human well-being as ecosystem services It also investigates the impacts of drivers on homegarden systems in rural areas in three countries These studies involved comprehensive literature reviews and field survey along with a framework of the Millennium Ecosystem Assessment Four types of ecosystem services—provision, regulation, cultural, and support—were assessed and compared We found that traditional homegardens maintain high ecosystem diversity especially in rural areas; however, recent socio-economic changes are converting subsistence-oriented homegardens into commercial ones Future challenges for further research include how to enhance the resilience of homegarden systems against socioeconomic and global climate changes by integrating traditional homegarden systems, modern technology, and the global economy

& 2013 Elsevier B.V All rights reserved

Contents

1 Introduction 125

2 Methodology and materials 125

2.1 Methodology 125

2.2 Study area 125

3 Results 126

3.1 Scale, structure, and diversity of homegarden systems 126

3.1.1 Scale 126

3.1.2 Structure of homegarden systems 126

3.1.3 Vertical structure of homegarden systems 127

3.1.4 Diversity in homegarden systems 129

3.2 Ecosystem services provided from homegarden systems 129

3.2.1 Provisioning services 129

3.2.2 Regulating services 131

Contents lists available atScienceDirect

Ecosystem Services

2212-0416/$ - see front matter & 2013 Elsevier B.V All rights reserved.

n Corresponding author Tel.: +81 3 5467 1212; fax: +81 3 5406 7347.

E-mail address: mohri@unu.edu (H Mohri)

3.2.3 Cultural services 132

3.2.4 Supporting services 133

3.3 Biodiversity 133

4 Discussion 133

4.1 Drivers of change in homegarden systems 133

4.2 Homegarden studies and global initiatives 134

5 Conclusion 134

Acknowledgments 134

References 134

1 Introduction

A homegarden is a garden surrounding a residence that

provides various goods and services to members of the household

A homegarden is usually a small-scale supplementary food

pro-duction system designed for local inhabitants, but sometimes it

mimics natural, multilayered ecosystems (Hoogerbrugge and

home-garden as a land use system with a structure resembling a forest

and one that combines the natural architecture of a forest with

species fulfilling the social, economic, and cultural needs of people

A homegarden is often considered part of an agro-socio-ecological

system that comprises domesticated plants and/or animals, as well

as people (Soemarwoto and Conway, 1992) By producing a variety

of fruits, vegetables, and non-timber forest products, homegardens

income

The majority of homegardens are distributed in East and West

Africa, South and Southeast Asia, Pacific Islands, and Mesoamerica,

which suggests that homegardens are predominantly a tropical

phenomenon (Kumar and Nair, 2006) Tropical homegardens are

considered one of the oldest forms of managed land use activity

next to shifting cultivation (Kumar and Nair, 2004) Various studies

have been conducted on these homegarden systems, but most of

them focus on physical structure, function, and ecological

struc-ture or a specific ecosystem service in a particular study area (e.g.,

research, despite the structural and functional similarities

between various homegardens (Kumar and Nair, 2004) A

chal-lenge in homegarden research is the use of commonly accepted

research frameworks and procedures (Kumar and Nair, 2004)

Agroforestry and traditional production systems that include

homegardens are recently reevaluated as effective measures for

adapting to climate and ecosystem changes (Rao et al., 2007;

Takeuchi, 2010) However, several studies present empirical

evi-dence demonstrating how a homegarden system can contribute to

the enhancement of adaptive capacity

The objectives of this research are as follows:

(a) To investigate the scale, structure, and diversity in

home-garden systems of Southeast Asia countries

(b)

To assess the biodiversity and ecosystem services provided by homegarden systems

(c) To identify recent changes and drivers of these changes, includ-ing climate change, on homegarden systems in rural Asia

2 Methodology and materials 2.1 Methodology

We have used the Millennium Ecosystem Assessment (MA) framework to evaluate the interaction among various services offered by homegarden systems and current drivers of change to

managed and modified by humans to avail ecosystem services, it is

an important source of the maintenance of local biodiversity The MA framework focuses mainly on linkages and dynamic interactions between ecosystem services and human well-being (MA, 2005) In addition to the dynamic process of evolution in homegardens, sociocultural and economic factors alter the human condition, while various natural factors influence ecosystems

On the basis of the MA framework, a comprehensive literature review was conducted As listed in the references, a total of 104 books, peer-reviewed journal articles, and conference papers were examined Distribution of publications is diverse in terms of publication year and theme Almost equal numbers of literature for three countries’ homegarden studies are referenced to identify components, spatial layout, temporal/spatial scales, diversity, and functions of each system by country In addition to the literature

2.2 Study area The homegarden is a traditional land use system that has evolved from prehistoric times (e.g., hunters and gatherers),

reported that the homegardens of Java originated in the 7th millennium BC The historical records suggest that they were attached to temples, palaces, elite residences, and the homes of

Table 1

Professional workshops in Indonesia, Sri Lanka, and Vietnam.

Workshop date 6–8 January 2012 17–19 September 2011 30 June–1 July 2011

Workshop venue Gadjah Mada University, Yogyakarta, Indonesia Peradeniya University, Kandy, Sri Lanka Vietnam National University, Hanoi, Vietnam

common people The homegarden system originated in Central

Java and parts of East Java, spreading to West Java in the mid-18th

century (Terra, 1954) Early references to a garden in ancient

Sri Lankan literature that resembled modern homegardens can

be found in the ancient epic Ramayana (Puri and Nair, 2004;

Kumar and Nair, 2004) This garden type has evolved into a

multistoried vegetation plot established by rural families around

their homes, using an ingeniously selected mixture of multiple-use

species of both indigenous and exotic origin with complementary

ecological characteristics (Gunatilleke et al., 1993) In the Kandyan

region, rural and semi-rural tree gardens were also referred to as

forest gardens owing their social functions and links to local

Jacob and Alles, 1987) The VAC system which stands for

Vuon-Ao-Chuong in Vietnamese, which translates to Garden-Pond-Livestock

pen, originated in the Red River delta and midlands of northern

Vietnam and utilizes land for carrying out various

agri-aquacultural activities in domestic dwellings (Trinh et al., 2003)

Implementation of the Doi Moi policy in 1986 promoted the VAC

system with an aim to increase and stabilize the nutritional

standard of poor rural people (Luu, 2001) Consequently,

inte-grated farming has spread extensively across Vietnam especially

irrigated lowlands, rainfed uplands, and semi-urban areas, and

almost 44% of all households now have such a system (Luu, 2001;

There are many types of homegarden systems worldwide This

paper focuses on three countries in Asia—Indonesia, Sri Lanka, and

Vietnam—each of which has different characteristics depending on

the socioeconomic and geographic conditions of their land use

forms However, other countries such as India or Bangladesh have

focuses on one particular kind of homegarden in each country,

such as the Pekarangan, Kandyan, and VAC system

Indonesia is the world′s largest island nation and has diverse

land use patterns and various bioproduction systems The

devel-opment of oil palm plantations has been a primary driving force of

systems exist in different areas (Kaya et al., 2002;Kehlenbeck and

typical traditional homegarden system in Java, known as the

Pekar-angan This is generally managed by individuals who grow various

products, including timber, vegetables, and fruits (Wiersum, 2006)

Sri Lanka has the highest percentage of rural population among

the Asian nations, which reached 85% in 2010 (World Bank, 2011)

Kandyan homegardens play an important role both as a link to

agricultural and natural landscapes and as a source of income in

the country′s midlands (Pushpakumara et al., 2010)

and has shown rapid economic growth as a socialist country with

relatively stable political conditions andflexible economic policies

Agricultural production in Vietnam is expected to expand, but

traditional bioproduction systems, including the VAC system

aquaculture (IAA) system in Vietnam This integrated farming

system has spread across the entire country

In addition, this study initiated a new research project to

investigate a strategy for enhancing resilience to climate and

ecosystem changes utilizing traditional bioproduction systems in

rural Asia The project was supported by the Ministry of the

Environment, Japan from 2011 to 2013, and selected Indonesia,

Sri Lanka, and Vietnam as case studies We know that homegarden

systems also exist in areas other than Asia, but as a pilot

comparative study on homegarden systems, it was reasonable to

start with these three Asian countries.Table 2lists their biophy-sical and socioeconomic features

3 Results 3.1 Scale, structure, and diversity of homegarden systems This section summarizes the spatial scale, temporal scale, structure, and layout of homegarden systems Both the scale and structure of homegardens vary according to the physical, social, and ecological attributes of the area

3.1.1 Scale Spatial scale In terms of land area, the spatial scale under homegardens varies depending upon the climate, soil type, topo-graphy, rainfall, economic activity, and culture Twenty percent of the total area in West Java is occupied by homegardens, while about 70% of households in the Kandy area have homegardens Homegardens cover 20% of the total land area in Java overall

total cultivated area in Sri Lanka (Verheij, 1982;Ensing et al., 1985) The area of individual homegardens varies from a few square meters to hectares However, in general, small land management units commonly cover an average land area of 0.6 and 0.4 ha in Java and Kandy, respectively The total area under gardens, average size, and range of area and pond areas for selected homegardens are shown in Table 3 It is difficult to define a general scale of integrated homegardens in Vietnam because the VAC system has spread irregularly across the country and land has been allocated directly by the government The Mekong region has larger home-gardens, averaging 0.75 ha, than the northern part of Vietnam, which averages 0.14 ha At 0.15 ha, pond sizes are the largest in

et al., 2003) In the northern Vietnam uplands, the garden area ranges from 0.01 to 1.5 ha and thefishpond area ranges from 0.001

to 0.015 ha, in comparison with the lowlands where they range

(Luu, 2001)

Temporal scale This refers to the time and labor spent in managing homegardens as a subsidiary activity along with the primary activity of farming In general, homegardens require minimal labor, which is mostly provided by household members

change regionally according to the area of homegarden, intensity of

occupation (Torquebiau, 1992) According toStoler (1978), a max-imum of 8% of total working time is spent on homegardens, which might reach up to two persons per day in peak seasons (Ninez, 1986) In Java, the labor requirement is comparable mainly in homegardens, ricefields, and kebun talun (Christanty et al., 1986)

In Kandy, apart from household members, labor is hired for skilled operations (Jacob and Alles, 1987) such as harvesting cash crops such as cloves, black pepper, and tea Most VAC homegardeners are relatively young (35 years on average) and family members main-tain these farming activities For households, the average number of family members isfive and labors is 2.85 (Trinh et al., 2003).Table 4 shows the time spent and labor input in homegardens for selected countries

3.1.2 Structure of homegarden systems Homegarden gardens’ vertical and horizontal structure changes

cul-tural, and ecological attributes (Abdoellah et al., 2001) The Javanese and Kandyan homegardens represent complex horizontal zoning and vertical stratification at different heights with a high

diversity of species, resulting in intimate plant association in a

virtually closed canopy structure, on the other hand VAC system

has a simpler vertical structure

3.1.3 Vertical structure of homegarden systems

In Javanese homegardens, the ground level is occupied by

starchy food plants, vegetables, and spices, followed by fruit trees

and cash crops in the next layer, and tall trees such as coconut and

structure and main species present at different levels of the

frequency of occurrence suggests that in Kandyan homegardens,

the highest canopy layer is dominated by jackfruit and coconut

trees, followed by areca nut,fishtail palm, gliricidia, mango, and cloves in the next canopy, and coffee in the lower canopy In the ground layer, the species vary from one garden to another However, recently it has been observed that the homegarden structure can be affected by factors such as population density, socioeconomics, proximity to the market area, owners’ preference, and management objectives

Horizontal structure of homegarden systems A large number of

pat-terns and are planted in order to achieve maximum space

(Christanty et al., 1986) Apart from these factors, management-associated aspects are also important to determine the horizontal zoning in the front, back, and sides of the house On the basis of a

Table 2

Biophysical and socioeconomic features of homegardens in the study areas.

Characteristics Javanese homegardens Kandyan homegardens VAC system

Location/country Javanese/Indonesia Kandy/Sri Lanka Vietnam

Population density(person/km 2

Eco-zone Humid; medium altitude and

lowlands

Humid; medium altitude Red River delta: Tropical to

subtropical, midlands: tropical and subtropical, lowlands: tropical, Mekong delta: Tropical

Relative humidity(%) Average 75 65–80 (day) and 75–90 (night) 82

Dominant soil type Reddish brown to brown latosols Reddish brown latosol to immature

brown loam

North: Loam and sandy loam, Central: Bazan, South: Alluvial clay, Mekong delta: Clay

Land tenure Privately owned b

Mainly privately owned Privately owned (allocated by

government) Classification Traditional and commercial Traditional, commercial, mixed Market orientation Subsistence/commercial Commercial with subsidiary

subsistence

Subsistence/commercial

Net income/family 6.6–55.7% of family income and

average of 21.1% depending on size, family needs, and composition of homegardens c

30–50% of family income d 30–60% of family income

a

Fernandes and Nair (1986)

b

Wiersum (1982).

c

Soemarwoto (1987)

d

Pushpakumara et al (2010)

e General Statistics Office of Vietnam (2013)

Table 3

Total area under homegardens, mean management unit, and range of management unit in homegarden systems.

Total area under homegarden of

cultivated area (%)

20% c 30–40% d North: 27%, Central: 70%, South:

34%, Mekong Delta: 47% e

Mean management unit (ha) 0.6 a

1.0 a

/0.4 b

North: 0.14, Central: 0.27, South: 0.28, Mekong Delta: 0.75 e

Range of management unit (ha) 0.01–3.0 a 0.4–2.2 a /0.05–2.5 b North: 0.05–0.32, Central: 0.02–

1.0, South: 0.08–0.72, Mekong delta: 0.2–2.2 e

72, Mekong Delta: 1500

a

Fernandes and Nair (1986)

b

Pushpakumara et al (2010)

c

Wiersum (1980) , Terra (1954) , Verheij (1982)

d Ensing et al (1985)

e Trinh et al (2003) , Luu (2001)

literature review andfield observations, we have drawn an aerial

view for each sample layout (Figs 1–3

In Kandyan homegardens, the horizontal zoning of planting is

significant correlation exists between different species with tree

species dominating (McConnell, 2003) Layouts of the VAC system show a combination of garden, pond, and livestock pens, although

condi-tions, culture, and economy According to (Trinh et al., 2003), there are four basic types of VAC systems in Vietnam: the homegarden

Table 4

Time spent, cutting and harvesting cycle, labor spent, and division of labor in homegarden systems.

Time scale Javanese homegardens Kandyan homegardens VAC

Time spent on homegardens 1 h/week/100 m²a

57 man days/year c

220 days/year h

Cutting/Harvesting cycle Irregular work schedule b

Continuous harvest depending on the output from different crops

Continuous harvest

Labor spent Small amount of time and family

labor spent during free time after work d

Relatively small amount of labor by household members f

Household commercially manages VAC spent more time Less labor and capital on the homegarden in households that have other income sources

Division of labor Land preparation & cultivation of

tree crops by men, cultivation of annual crops by women.

Harvesting is done by all household members, but marketing is predominantly a male activity e

Equal division of labor between males and females with few activities being exclusively the domain of either sex g

Usually, family members manage the farming activities

a Stoler (1978)

b Christanty (1985).

c

Torquebiou (1992).

d

Laumans and Kasijadi (1985)

e

Christanty et al (1986) , Laumans and Kasijadi (1985) , Matahelumual and Verheul (1987)

f

Pushpa kumara et al (2010)

g

Jayawardena and Jayathilake (1998)

h Trinh et al (2003)

Table 5

Vertical stratification in homegarden systems.

Stratum Height in meters (m) Javanese homegardens Kandyan homegardens VAC

Level 1-ground level o3 Starchy food plants,

vegetables, and spices- Languas, ganyong, xanthosoma, cassava, sweet potatoes, taro, chili peppers, eggplant, spinach, and wing bean

Vegetables, medicines, spices, fruits trees, subsistence, and cash crops- Okra, eggplant, beans, tea, cassava, ginger, turmeric, anthurium, pineapple, and chili peppers

Flowers, medicinal plants, herbs, spices, fruits, plants in the pond (or on the banker), and vegetables

Level 2-lower stratum 3–10 Fruit trees and cash

crops-Bananas, papayas, mango, jakfruit, and other fruit trees;

Soursop, jakfruit, pisitan guava, and mountain apple;

or other cash crops such as cloves

Medicines, food staple, subsistence, and cash crops-Vanilla, banana/plantain, cacao, coffee, passion fruit, betel vine

Fruits trees- Lucuma mamosa, orange, tangerine, grapefruit, longan, rambutan, kapok, and water apple; bamboo, cashew, Acacia aneuna

Level 3-lower-middle

stratum

10–15 Other trees for

building material and fuel wood-coconut trees and other trees (e.g., Albizia)

Subsistence food staple, seasonal fruits and cash crop- papaya, pepper, avocado, mangosteen, breadfruit, rambutan, citrus

Coconut, areca, bamboo, eucalypts, cajeput, and Caplophyllum inophyllum Level 4-upper-middle

stratum

15–25 Fruits, timber, medicines, cash

crops-mango, bamboo, areca palm, nutmeg, clove, rubber, wild breadfruit, kitul palm Level 5-upper stratum 25–30 Timber, cash crops, fiber and oil seed

crops-durien, talipot palm, jak, coconut palm, kapok, pepper

Christanty et al (1986) , McConnell (2003) , Trinh et al (2003) , An (1997).

combined with (1) fruit trees in South Vietnam; (2) pond and

covered livestock areas around the Red River delta and central

Vietnam; (3) vegetables in the Red River delta and central

Vietnam; and (4) forest trees, which is the type of VAC system

that generally consists of both and upper and lower levels (An,

1997) Over the past years, many attempts have been made by

either local organizations such as the Southern Vietnam Gardening

Association (VACVINA) or foreign investors to integrate new

technologies and introduce new crop species into the VAC system

For example, a VAC combined with rice cultivation (particularly

hybrid rice) or forestry is called RVAC VACB (VAC combined with

biogas) is applied in many places (Zhu, 2006) In addition, some

communes have community- or village-scale VAC systems that connect each household to a community farm and lake The community-scale systems grow more products suitable for sale

to larger markets (Ueda, 1996)

Several of the common differences among the three home-gardens are related to the position of service area and species layout All services such as toilets, bathrooms, wells, smaller fishponds, cattle sheds, and garbage dumps are located in the backyard of the Javanese garden, thus this area is larger than the front yard The VAC system is opposite of this, with the front yard

well that are well-organized in front of the house In Kandy homegardens, a pond and cattle shed are rarely seen Poultry is common in all the homegardens located in back yards In both Javanese and Kandy homegardens, ornamental species, fruit trees, and cash crop species are planted in the front yard for aesthetic and security reasons, while vegetable plants and spices, some fruit

plants are planted in front of the house in the VAC system 3.1.4 Diversity in homegarden systems

Diversity in homegardens’ structure, composition, and function

is a result of associated socioeconomic changes In the past, several studies conducted on Javanese homegardens illustrated their diversity as an outcome of differences in geographic location, climatic condition, cultural factors, role in the farming system, and

important factors and highlighted the importance of livelihood condition in determining the structure and composition of home-gardens On the basis of household economy, Wiersum suggested four types of homegardens: survival, subsistence, market, and budget gardens Apart from market economy, access to markets

house-lots in combination with some small area of paddy land

Likewise, components and types of VAC are dependent on geo-graphy, commune policy, and personal decision as mentioned above, although the basic structure, garden, pond, and livestock are always common (Edwards, 2010) Coastal areas inevitably weighed on aquaculture and mountainside focused farming and forestry (An, 1997) As previously mentioned, VAC has been customized to improve its productivity, which leads to more diversity in the system itself For example, the more commercial

3.2 Ecosystem services provided from homegarden systems The homegarden system provides key ecosystem services that may be conceptualized as provisioning, regulating, cultural, and supporting services In addition, homegardens serve as habitat for

conservation

3.2.1 Provisioning services Provisioning services are those resources supplied by home-gardens to human communities, which include food products, timber for construction, fuel in the form of wood and charcoal, and

services offered by homegarden systems

3.2.1.1 Food Homegardens provide nutrition in various forms such as food crops, fruits, vegetables, livestock, aquaculture, wild

Fig 1 Schematic view of Javanese homegarden (a) road, (b) ornamental, cash

crops and fruit trees, (c) pathway, (d) fruit trees, (e) tall shady trees, (f) buruan

(cleared patch), (g) house, (h) vegetable plants and spices, (i) hedges along the front

and side boundary, (j) bathroom, (k) well, (l) poultry, (m) fishpond, (n) aquatic

plants and grasses, (o) fruit trees, (p) cattle shed, (q): latrine, (r) tall trees and

bamboo clumps, and (s) garbage dump.

Fig 2 Schematic view of Kandyan homegarden (a) road, (b) ornamental and fruit

trees, (c) pathway, (d) ornamental shrubs, (e) cleared patch, (f) house, (g) vegetable

plants and spices, (h) shrubs and hedges along the side boundary, (i) fruit trees, and

(j) tall timber trees, coconut and spice trees.

Fig 3 Schematic view of VAC (a) road, (b): pathway, (c) fishpond, (d) aquatic

plants and grasses along fishpond, (e) well, (f) vegetable plants spices and bonsai,

(g) cattle shed, pig pen and storage, (h) bamboo cluster along the side boundary,

(i) house, (j) coffee plants alongside boundary, and (k) fruit trees in backyard (The

figures are drawn by Shruti Lahoti.)

plants and animal products Each subcategory is explained in

detail below

composition of various plant categories: food crops, fruits,

vege-tables, or medicinal and spice trees.Table 5lists the major species

found under different plant categories in the study areas In

Javanese homegardens, the major food crops are maize, coconut,

taro, and cassava Kandyan homegardens are similar to Javanese

ones with coconut, cassava and jackfruits as the major food crops

On the other hand, VAC farmers tend to grow sweet potato, corn,

or banana, which provide higher market prices As mentioned

above, the species composition varies in different homegardens

under different plant categories

Livestock Animal husbandry is an integral part of homegardens The choice of animal species is determined by various factors such

as sociocultural, environmental,financial, and religious concerns (Soemarwoto, 1987) Milk and egg production provide nutritional security to rural households and a source of additional income Animal waste provides manure required to maintain soil fertility and production sustainability However, in Kandyan gardens, the livestock component is relatively less important (McConnell, 2003) A variety of livestock can be found in different VAC house-holds Pigs, cows, ducks and chickens are common in most places

Table 6

Provisioning services provided from homegarden systems.

Provisioning services Javanese homegardens Kandyan homegardens VAC system

Food Crops Major food crops Rice, maize, coconuts, taro, sweet

potato, cassava, yam, ganyong, spinach, wing bean, eggplant, leafy vegetables, etc.

Rice, maize, green gram, cowpeas, cassava, coconut, jackfruit, sweet potato, taro, yam, juggary and treacle from fish tail palm.

Rice, corn, sweet potato, citrus, black bean, cassava, yam, banana, coconut, jackfruit, banana, luffa, orange pomelo, longan, kumquat, spinach Major cash crops Coconut, banana, orange, mango,

jackfruit, papaya, guava, coffee, clove, etc.

Cacao, cloves, cocoa, coconut, banana, coffee, jackfruit, mahogany, nutmeg, pepper and other spices, teak, jak and other timber trees, etc.

Bamboo, pineapple, jackfruit, guava, papaya, banana, lime, orange, pomelo, lychee, pear chilies, kangkon (in the fishpond), etc h

Livestock Chickens, cows, goats and sheep g

Poultry and cattle e

: 15% of householders rear livestock a

Buffalo, cow, pig, chicken, duck j

Aquaculture Fishpond as a part of system NA Carps, robu, mrigal, mud

carp, tilapia (Limited number of case), soft shell turtle, frogs, snakehead fish, and catfish h

Wild plant and animal food products Weed species used for herbal

medicine, roofing, vegetables, and fodder g

Local breeds of chicken, eggs, goat and cow milk d

Guava, vegetables, longan, lychee, chilies, cassava, bamboo i

Fiber Timber Important source of building material

e.g., Sandoricum koetjape, crescentia cujete, jack fruit

Supplies 48% of the total sawlog demand of the country c

Importance source of building materials and sawlog

Fuel wood Supplies 40–80% of the rural fuel

wood f e.g., Laban, bamboo, muntingia calabura

Supplies 38% of the total biomass fuel demand of the country c

Block wattle, litchi, guava, Melia azendarach, Casuarina equistifolia, Mangifera, and bamboo h

Genetic resources Provides habitat for small wild

animals such as birds, reptiles, and amphibians

Provides habitat for a wide range of species, from soil micro life to insects, including pollinators, and from crops, trees to mammals, birds, and other wildlife d

Provides habitat for small wild animals such as birds, reptiles, amphibians, insects and plants crops

Natural medicines Extracts from medicinal plant

provides treatment against various diseases and is consumed

as a way of healthy life style

Most herbs and trees are used medicinally a

e.g., Turmeric, ginger, vanilla, areca palm, clove, nutmeg, etc.

Plenty herbs and medicinal plants used medicinally such as ginger, clove, artemisia, etc.

Nutrition Supplies 18% calories and 14%

proteins b

, and provides vegetable proteins, carbohydrates, vitamins, and minerals

a Pushpakumara et al (2010)

b

Ochse and Terra (1937)

c

Gunathilake (1994)

d

Pushpakumara (2000)

e

Perera and Perera (1997b)

f

Wiersum (1977)

g Soemarwoto et al (1985)

h Vien (2003)

i

Trinh et al (2003)

j

Such livestock is raised not only to sell or consume but also to use

in ceremonies such as weddings or funerals (Trinh et al., 2003)

Livestock excretions are also fully utilized to fertilize gardens and

fishponds (Luu, 2001)

3.2.1.2 Aquaculture Aquaculture has been considered a main

source of food security in terms of consumption and income

generation Increasing global and local demand for aquaculture is

greater than ever (Ahmed et al., 2002;Muir, 2005) Aquaculture is

one of the three functions of the traditional homegarden in

Vietnam Total production has been dramatically increased over

recent years; as of 2002, its amount was almost triple what it was

in 1990 (Vinh, 2005) Although the diversity of species in the pond

is quite rich, intensification can be seen especially close to big

cities such as Hanoi (Edwards, 2010)

Wild plant and animal food products Various weed species have

few species are also used as food Considering that 10 very

commonly found weed species are known to have medicinal

values (Sangat, 1988), weeds may be grown intentionally as useful

plant species in Javanese homegardens

3.2.1.3 Fiber Although little research has quantified the importance

source of fuel and timber for rural households.Wiersum′s, 1977study

reported that Javanese homegardens supply 51–90% of wood fuel to

the rural population In Sri Lanka, Kandyan homegardens are

considered the single most important source offiber in non-forested

land (Gunathilake, 1994) The Kandyan homegardens also help in

preventing deforestation by providing forest products (Pushpakumara,

2000) In Vietnam, the northern mountainous areas mainly have a

VAC system combined with forestry Timber products are the primary

goods sold, but the region also has a small (and diminishing) lacquer

industry

3.2.1.4 Genetic resource The high species diversity of the

home-gardens is a potential genetic resource for a variety of plants and for

future breeding programs to increase the quality and quantity of

However, very little inventory work has been done to determine

the importance of homegardens as a genetic resource; these studies

are limited to a few from West Java In Sri Lanka, many of the

endemic species found in these gardens are generic to the

non-timber forests For example, Caryota urens (kithul as it is known in the

local Sinhala language) is used to make alcoholic beverages, jaggery,

and a myriad other products with reasonably established markets

(Gunatilleke et al., 1993) In Vietnam, homegardens play a significant

role in conserving indigenous species and rare plants that are often

dismissed as a result of development-induced changes in land use

(Trinh et al 2003)

3.2.1.5 Natural Medicine Homegardens are an important source of

production and in situ conservation of medicinal plants (Rao and Rao,

2006) but relatively little data is available on the extent of medicinal

products used, extracted, and sold from homegardens Some of the

deliberately planted species have exclusively medicinal values, while

other multipurpose species combine medicinal values with food or

spice value Although the economic values of the medicinal plants in

homegardens are not exploited, they are widely used within the

family and community for medicinal purposes (Rao and Rao, 2006)

For example, Kubota et al., 1992reported 26 medicinal species in

homegardens of Java and in Kandyan homegardens, medicinal plants

are recognized as the second most important resource (Perera and

Perera, 1997a) For example, the bark of cinnamon is used medicinally for treating diarrhea, nausea, and vomiting in Sri Lanka and Indonesia (Rao and Rao, 2006) Medicinal plants are also

(2003), diversity of medicinal plants in a garden is higher than others, including vegetables and fruits

3.2.1.6 Nutrition Homegardens play a key role in providing nutritional and food security to households by ensuring a steady supply of necessary vegetable proteins, carbohydrates, vitamins, and minerals (Abdoellah, 1985), particularly during lean periods when other food supplies are inadequate In Indonesia, studies

calories, while homegardens provide more calcium and vitamins and a portion of the of calories and proteins consumed by an entire village (Ochse and Terra, 1937) Kandyan homegardens play

a pivotal role in providing low-cost food and ensuring nutritional intake, with direct access and a steady supply owing to the mix of crops they contain, including vegetables, fruits, and others

throu-ghout the year, there is usually something to harvest in a Kandyan homegarden (Pushpakumara et al., 2010) The VAC system also plays a significant role in providing nutrients With higher productivity of the VAC products, many families now have incomes almost 15 times higher than they would from rice farming, simply because the increased protein and vitamins make meals more versatile and nourishing (Nguyen, 1997)

3.2.2 Regulating services Recent studies on ecosystem services and environmental

services that it offers (Jose, 2009; Rao et al., 2007) Regulating services include functions such as sequestration of carbon from the atmosphere, soil erosion regulation, waste treatment, water purification, pest regulation and pollination, all of which help in maintaining a sustainable supply of many provisioning services provided by homegardens

3.2.2.1 Climate regulation The multilayered plant canopies in homegarden systems have the potential to regulate the climate

on a local and global scale On the local level, the dense vertical structure of trees helps in controlling microclimatic conditions by

influencing the air temperature, radiation flux, soil moisture, or wind speed and maintaining an ambient temperature (Rao et al.,

moderating and ameliorating the microclimatic conditions, homegardens play an important role in macroclimate regulation through carbon sequestration The woody biomass of this species-rich and highly diverse land use system provides products for subsistence and commercial purposes and offers potential for carbon storage In regard to climate change, the important regul-ating service offered by homegardens on a global scale is the

atmosphere

stored by Javanese homegardens in their above-ground biomass is equivalent to secondary forests of similar age in the same area The author also suggests that the homegarden system has a substan-tially higher aboveground carbon stock than that of vastly degraded and underutilized land such as Imperata cassava systems

in Indonesia (Roshetko et al., 2002) Thus, homegardens have the

Mechanism (CDM) projects

Tropical forest homegarden like Kandyan homegarden has a

great potential of carbon storage as it makes a mosaic with natural

Lankan homegardens have high potential for small-scale

affores-tation or reforesaffores-tation (A/R) projects under the CDM that allow

bundling of individual small plots Of the Kandyan homegardens,

85% use no inorganic fertilizers, potentially serving as a model for

successful production without harming nature (Szott and Kass,

1993) Kandyan homegardens provide 31% of the vegetation cover

of the entire district, complementing the 17% provided by natural

forests, which is below the national average of 21% (Pushpakumara

et al., 2010)

For the Vietnamese case, very little studies have investigated on

the relationship between VAC system and climate regulation (Leisz

system especially with forestry has greater potential for the carbon

storage The Vietnamese government has established working

groups for CDM projects and the CDM National Executive and

Consultative Board (CNECB) under the International Cooperation

Department of Vietnam Most ongoing CDM projects are related to

hydropower, but in 64 of 83 projects, attempts have been made to

use the project for forestry and greenhouse gas (GHG)

(Depart-ment of Meteorology, Hydrology and Climate Change, 2011) A

study has been conducted on the effects of land use change on

GHG emission in the northern mountainous area of Vietnam

Although cultivation is not permitted on sloping forestland,

various farming activities shift cultivation to what is often

con-sidered forestry Government policy has prohibited swidden and

fallow cultivation and has promoted permanent cultivation Many

of these projects have been transformed into the VAC system

combined with forestry However, according to the study, shifts in

land use system such as the swidden farming- to

homegarden-based system, have negative effects because livestock activities,

rice cultivation, and other agricultural activities requiring the use

of fossil fuel actually increase GHG (Leisz et al., 2007)

3.2.2.2 Erosion regulation One of the most important ecological

functions provided by homegardens is the regulation of soil

erosion The low rate of erosion is achieved because of high

species diversity, multilayered canopy structure, and a thick layer

of litter with dense root architecture that guards the soil against

the erosive force of raindrops (Torquebiau, 1992) Moreover,

homegardens are not harvested completely, thus keeping the

erosion rate low (Gajaseni and Gajaseni, 1999) Although soil

erosion is widespread in Sri Lanka, especially in the wet zone,

to natural forests and usually less than 1% of the annual cultivation

2010)

3.2.2.3 Waste treatment and water purification The VAC system is

known as a recycling system; home waste, garden, pond, and

livestock pens are all well connected and designed to utilize any

waste from each homegarden component Besides being sold and

and livestock Excretory substances from humans and animals are

utilized as manure in vegetable and fruit gardens Ponds, gardens,

toilets, and livestock pens are usually linked through pipelines

(Ueda, 1996) These wastes are also optimized to generate

electricity through a biodigester Biogas plants have been

promoted by various organizations and initiatives According to

Bodganski et al (2010), the gardening association VACVINA has

installed 1000 biogas plants and trained technicians in the Thanh

Hoa province In the extended territory of the Kandyan gardens,

such as in the Badulla district, ponds that regulate waterflow and offer various services can be found; these are called buffalo ponds

in Sri Lanka (Wagachchii and Wiersum, 1997)

3.2.2.4 Pest regulation and pollination In homegardens, traditional management practices using livestock are used to control pests For example, in Java, peanuts are planted near the house to attract

birds and ducks are used to control insects (McConnell, 2003) Although many authors have suggested that high species diversity and intimate plant associations also minimize the risk of pests and diseases in homegardens in comparison with monocropping, there

is no scientific evidence or research on the pest-regulating services provided by homegardens

Although animals often do not play an important economic role

in homegarden systems, they are essential for various biological processes such as pollination, natural hybridization, and seed dispersal For example, Kandyan homegardens often provide habitats for small mammals, birds, bats, and insects, all of which play an important role in pollination and seed dispersal

pasturage potential in two Kandyan homegardens and found that the number of bee foraging plant species accounted for 37.5% of the total number recorded from the study areas In the two Kandyan homegardens, Cocos nucifera (coconut) and Falcataria

impor-tant sources of pollen and nectar, respectively, while many economically important species such as Swietenia macrophylla (mahogany), Melia dubia (lunumidella), Myristica fragrans (nut-meg), Artocarpus spp (jack and breadfruit), Mangifera indica (mango), Persea gratissima (avocado), Coffea arabica (coffee), and Camellia sinensis (tea) were also identified as important bee plants (Mendis et al., 1985) Because of a lack of research focusing on this aspect of homegardens, it is difficult to assess the significance of homegardens in the overall process of pollination in Javanese homegarden and VAC systems

3.2.3 Cultural services Studies have shown that culture strongly influences the selec-tion of plants cultivated in homegardens In Javanese homegar-dens, medicinal plants, used to treat and protect against diseases for a healthy life, are more than just vegetable plants In contrast, more vegetables and ornamentals are planted in Sudanese home-gardens to suit people′s food and visual preferences; the people

matrilineal societies Homegardens also play an important social role in Javanese community life Every homegarden has a clear patch shaded by tall trees so children can play and elders can interact during their free time The gardens are also an important social status symbol (Ahmad et al., 1980) Traditional homegardens are generally bounded by a living fence of shrubs or small trees that allow easy access to fetch water, collect medicinal plants, and pass through There is no concept of trespassing, thus homegardens help

tradi-tional concept of Rukun Tetangga (neighborhood) allows free sharing of homegarden products among relatives and neighbors, thereby fostering equitability within the community′s social fabric Kandyan gardens serve as a place for intra-family interaction, since outside labor is minimally used They also provide a place for exchanges in rural villages For example, the available garden in the village may serve as a medicinal output to the needy In addition, they offer a place to meet, for children to play, and for other small social gatherings, such as neighbors visiting to check

by introducing tourists to spice gardens having unusual species,

local herbs, or medicinal plants However, tourism has not been

developed in the homegardens of Java, despite the great potential

there for agro-tourism

For VAC farming, cultural value is significant for most

Vietna-mese farmers In general, farmers had little choice in decision

making before the Doi Moi renovation, for instance, in selecting

which plants to grow On the other hand, a homegarden is

a policy to undertake certain farming activities Some fruit species,

such as palm fruit, vine, and lime, are culturally important for rural

populations These products are often used for festivals and

s biggest festivals and the fruits used for this celebration are

determined by the types cultivated by the homegardener (Trinh

et al., 2003)

3.2.4 Supporting services

3.2.4.1 Nutrient cycling and soil formation Tropical forests are

sustain-able because of the dynamics of litter production,

decomposi-tion, and the subsequent bioelement release that also occurs in a

Javanese homegarden having greater litter fall than a typical forest

(Gajaseni and Gajaseni, 1999)

Thus, the homegarden system is a sustainable approach to

improve soil fertility by nutrient cycling and maintaining organic

matter, carbon content, and soil structure This issue is in need of

attention by the scientific community to carry out field studies and

coordinated research to highlight the importance of homegarden

systems in nutrient cycling and soil formation

3.3 Biodiversity

In order to understand the factors contributing to the

biodi-versity of homegardens, the resilience and evolution of the system

itself have to be studied (Galluzzi et al., 2010) However,

conserva-tion of biodiversity in tropical landscapes could be accomplished

through agroforestry systems, since it has largely ignored

Javanese homegardens, and 13 of them were protected species

However, a detailed inventory list and studies focusing on the

biodiversity of homegardens are lacking in Indonesia Many

endangered species that are diminishing in other areas of

Indo-nesia tend to be protected in homegardens In addition, many

seeds and crops imported from other countries have been adapted

for cultivation in most areas of the country Apart from providing

key ecosystem services, Kandyan homegardens are habitat for a

large range offlora and fauna, thereby connecting agriculture with

the natural landscape and thus helping conserve biodiversity

against the risk of population fragmentation and the need for

Pushpa-kumara et al., 2010) They are germplasm repositories of numerous

species (Pushpakumara, 2000) and are important for ex situ

conservation of germplasm by providing a gene bank The

pre-sence of high fruit tree diversity, various niche specialization,

feeding materials, nest specialization, and a very low level of

disturbances (Pushpakumara et al., 2010) enable high faunal

five orders and seven families; and a total of 35 birds belonging to

five orders and 14 families, including five endemic species In

Vietnam,Vlkova et al (2011)surveyed agrodiversity and found out

over 70 different plant species in a commune in the central Vietnam,

which depends on the size of each unit South Vietnamese

homegardeners, well known for traditionally growing a variety of fruits, have tree selection procedures and distinguishable layouts for their homegardens (Nguyen, 1995) According to (Trinh et al., 2003), although some trends of monoculture are seen in VAC farms, their level of biodiversity remains high in most places

4 Discussion 4.1 Drivers of change in homegarden systems Homegardens are dynamic and capable of responding to socio-economic changes resulting from rural transformation and

diver-sification of the rural livelihood (Peyre et al., 2006) Wiersum

specia-lized cultivation system and generating more primary production activities for rural populations, resulting in changes in the farming and homegarden systems In order to adapt to these socioeconomic changes, the subsistence-oriented homegardens are increasingly becoming more commercially oriented Although the impacts of such changes differ by region and depend on the intensity of rural

or urban transformation and socioeconomic changes, the home-gardens are showing different trends in development According to Wiersum (2006), the main trends are an extension in the overall size of homegardens and changes in their structure and composi-tion because of increasing commercializacomposi-tion The drivers of change are primarily socioeconomic factors, commercialization, population growth, change in the farming system, scientific innovations in the health care sector, introduction of invasive alien plant species, inheritance, urbanization, climate change, over-exploitation, and pollution

External market demand has led to cash crop production and monoculture, which affect species diversity Therefore, the struc-ture of homegardens, which plays an important role in various provisioning and regulating features, is being affected Scientific innovation in the healthcare sector strongly impacts the usage and validity of traditional medicinal plants in homegardens (Kumar and Nair, 2004) The outcome of commercialization is increased production, which is obtained by additional inputs in the form of pesticides and fertilizers This consequently changes a system

1992) Commercialization is also disrupting the social services of

equitability and causing fences to be installed around the home-stead to protect cash crops (Abdoellah et al., 2006)

Another threat to the traditional homegarden is the intentional and unintentional introduction of invasive plant species such as Acacia spp., Eucalyptus spp., Mimosa invisa, Mikania micrantha, and Calliandra calothyrsus (Richardson et al., 2004; Kumar and Nair, 2006) Exchange of seeds through botanical gardens has been a primary mode of deliberate introduction of alien plant species into

a country or ecosystem (Marambe et al., 2003) Similarly, seed exchange among homegardens may be a major source of alien plant species’ expansion Spread of aggressive exotics along with structural changes in rural bioproduction systems could reduce floristic diversity in the homegarden (Kumar and Nair, 2006) Population growth is an indirect driver causing land use changes such as the fragmentation of landholding, which leads

to a decline in the average size of homegardens, thereby decreas-ing income and forcdecreas-ing farmers to seek employment elsewhere (Christanty et al., 1986) In addition, because of urbanization, homegarden areas are reduced to catering to the housing demand

In this manner, the stable and sustainable system providing various ecosystem services is now being threatened by various