Keywords

1 Introduction

The global crisis has been affecting Indonesia in all aspects, such as a social crisis, political crisis, and economic crisis, as well as the environmental and ecological crisis. Those impacts have already touched most of Indonesian communities from the rural to the urban areas. To increase the ecological-social-cultural-economic welfare of the rural community in Indonesia, urgent action is needed to develop environmental conservation through traditional or complex agroforestry practices; thus, community welfare can be gained by eco-village implementation, which is balanced among the ecological, socioeconomic, and spiritual values of the community (Arifin and Arifin 2010). In the micro-level of landscape, pekarangan, a piece of land surrounding the house, is potential land for ex situ agrobiodiversity conservation through agroforestry, agro-silvo-fishery, and agro-silvo-pastura system practices.

As greenery open space, pekarangan has permanent vegetation. Therefore, ecologically the pekarangan is supposed to sequestrate carbon dioxide (CO2) from the air to be stocked in tree leaves, branches, trunks, roots, and soils. Pekarangan has a role not only in carbon (C) sequestration, but also in water resources management, agrobiodiversity conservation, and landscape beautification as part of the scheme of the payment for environmental services (PES) (Kaswanto and Nakagoshi 2012). The PES scheme is being proposed and tested in different contexts as a way to involve the local people in conservation practice (Nurhariyanto et al. 2010). Furthermore, the low carbon society (LCS) can be achieved through pekarangan, the traditional agroforestry practices in Java, Indonesia

The Pekarangan area was studied mostly in Java island because of the 5,132,000 ha of pekarangan in Indonesia, 1,736,000 ha are on Java (Prosterman and Mitchell 2002) (citing 2000 Statistical Yearbook of Indonesia, Table 5.1.1.). As in the distribution of croplands, the distribution of pekarangan is very unequal. Thus, for Indonesia as a whole, 40.28 % of households have less than 100 m2 of pekarangan, 25.24 % have 100–200 m2, 11.72 % have 200–300 m2, and 22.76 % have 300 m2 or more (Arifin 1998). Table 8.1 shows the distribution for the four provinces of Java. Pekarangans areas spread from rural, to suburban, to urban areas. The LCS could be achieved through pekarangan; so long as housing development is constructed by the horizontal building system, it is assumed the more built-up housing, the larger the numbers and area of pekarangan.

Table 8.1 Size distribution of pekarangan land in agricultural provinces of Java (percentages of households that have pekarangan in the size groups shown)
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2 Objectives of Research

The multiyear research on pekarangan has the objective to reconstruct and to revitalize traditional Indonesian agroforestry to achieve sustainable bioresources management systems on Java. Furthermore, this research calculates and assesses C sequestration, water resources management, agrobiodiversity conservation, and landscape beautification from pekarangan.

3 Methods

This study has been ongoing since 1996 in some watersheds of West Java Province for a period of 10 years. This study was divided into four stages with the activity targets in each stage as follows:

  1. 1.

    Stage I (1996–2000): Survey on traditional pekarangan bioresources in rural areas.

  2. 2.

    Stage II (2000–2003): Analysis interrelationships among components in pekarangan bioresource management system and evaluation.

  3. 3.

    Stage III (2003–2005): Reconstruction of a pekarangan bioresources management system.

  4. 4.

    Stage IV (2005–2007): Adaptation of the new biomanagement system and proposal of the reconstruction of the pekarangan bioresources management system.

Simultaneously, these pekarangan studies have been extended on Java Island under joint research with the Rural Development Institute (2006–2007), Hibah Penelitian Tim Pascasarjana Directorate General of Higher Education (DGHE) of Indonesia (2006–2008), Hibah Kompetensi DGHE of Indonesia (2008–2010), and joint research with the Global Environmental Leaders (GEL)s Education Program for Designing a Low Carbon Society (LCS) of Hiroshima University, Japan (2009–2013).

In this chapter, those results were demonstrated to show the conditions and the significant roles of pekarangan in Java, Indonesia. Several settlements of hamlets or villages within administrative boundaries were chosen as the study sites of a microscale research unit. Selection of the study sites in each small-scale catchment area was based on several considerations, as follows:

  1. 1.

    Elevation gradient: 200–500 m, 500–1,000 m, and >1,000 m above sea level (a.s.l.)

  2. 2.

    These study sites are located in the linear slope.

4 Results and Discussion

4.1 Traditional Agroforestry of Pekarangan

Pekarangan is the traditional and privately owned home garden, and an integrated system with an intimate relationship among human, plants, and animals. It is well known that this garden has multiple functions, such as conservation of genetic resources, soil, and water, crop production, and sociocultural relationships in the rural area. It is thought that pekarangan is an optimal and sustainable land use with high productivity in tropical regions (Arifin 1998). Arifin and Arifin (2010) stated that pekarangan is a kind of traditional agroforestry practice that is found in rural and agricultural landscapes beside kebun campuran (mixed gardens) and kebun talun (forest gardens). The design and structure depends on local and ecological knowledge of the surrounding communities. The survey showed that the western part of Indonesia practices agro-silvo-fishery, as there are many water resources, and in contrast, the eastern part of Indonesia practices agro-silvo-pastura because of lack of water (Arifin et al. 2008a).

Pekarangan fulfills an ecological function in that its multilayered vegetation structure resembles that of natural forests and offers habitats and niches for a diverse community of wild plants and animals (Albuquerque et al. 2005; Karyono 1990). This study has confirmed the performance of pekarangan at the smallest scale. Those provisions are the contribution of pekarangan for nutrition intake, income, wealth assets, family status, access to credit, control of production, and product marketing.

Some research, particularly pekarangan biodiversity based on urbanized vegetation structures, was conducted in the landscape ecological unit of Ciliwung and Cisokan Watershed, which covers the Bogor-Puncak-Cianjur (BOPUNJUR) region (Arifin 2004; Arifin et al. 2001). Species richness was elucidated for pekarangan starting from the upper stream reaches to the downstream portion of the watersheds. Landscape structure in the traditional agroforestry of the pekarangan system has horizontal and vertical diversity (Arifin et al. 1998). Based on plant function, horizontal diversity has been classified into eight groups: ornamental plants, fruit plants, vegetable crops, starchy crops, medicinal plants, spices crops, industrial plants, and others (Arifin 1998). It is found that the size of pekarangan and percentage of plant canopy coverage are larger from the upper stream reaches to downstream. However, the highest averages of individual numbers per pekarangan and species diversity index were found in the middle streams of Cianjur watershed (Table 8.2). This area is a transition zone between the lowland and mountainous areas (Arifin et al. 2001).

Table 8.2 Number of species and individual numbers per pekarangan in Cianjur Watershed
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Based on plant function, the lower parts of watershed have a smaller ornamental plant ratio (Table 8.3). Fruit plants were found in the downstream predominantly (30.4 %), followed by others (17.1 %), such as fuel wood species, wood for handicrafts material, and wood for building materials (Arifin 2004).

Table 8.3 Ratio of species number by pekarangan plant function in Cianjur Watershed
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In the BOPUNJUR region, changes of pekarangan plant diversity were studied along an urban–rural continuum as well as along an elevation gradient. The vegetation structure and composition of 115 pekarangans in six villages were investigated to determine the urbanization effects (Arifin et al. 1998). The six villages differed in urbanization level: one is a rural village, three are characterized as intermediately urbanized, and two are urban villages. In each pekarangan, both ornamental and crop plants were inventoried. Pekarangan sizes ranged from 30 m2 to 4,000 m2; the average size was 270 m2. In total, 440 plant species were grown in the 115 pekarangans; about half the species were ornamentals. The number of species in a pekarangan varies according to local physical circumstances, ecological characteristics of plants, kinds of animal species, and socioeconomic and cultural factors. Plant species numbers varied largely among the 115 pekarangans studied. Average species number per pekarangan were not markedly different between the rural, the intermediate, and the urban pekarangans (Arifin 1998 and Arifin et al. 1998). However, the average number of nonornamental plant species per pekarangan was markedly higher in rural than in urban pekarangan. The proportion of ornamental plants from total species increased with a higher level of urbanization (40 % in rural to 70 % in urban). Pekarangan size decreased continuously from rural to urban areas. In many densely populated tropical regions, pekarangans appear to be the last forest-like islands surrounded by increasingly extended, uniform staple crop fields. In these areas, pekarangans with their multilayered vegetation structure serve as an important habitat for wild flora and fauna. Pekarangans fulfill not only important ecological but also many social and cultural functions (Kehlenbeck et al. 2007).

Furthermore, a homestead plot survey on Java (Arifin et al. 2008b) was conducted in 144 pekarangan samples from three provinces: West, Central, and East Java provinces. The pekarangan samples covered two watershed units per province. Pekarangan size was divided into two groups: smaller than 120 m2 (small pekarangan) and between 120 and 400 m2 (moderate-size pekarangan). The total species number is 196 (Table 8.4), consisting of ornamental plants (103 species), fruit plants (29 species), vegetable crops (21 species), medicinal plants (13 species), spice crops (9 species), industrial plants (9 species), other plants (7 species), and starchy crops (5 species).

Table 8.4 Number of species by plant function in 144 pekarangan samples on Java Island
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4.2 The Dynamics of Pekarangan

Vegetation structure dynamics in pekarangan was analyzed between years 1996 and 2006 (Mayanti et al. 2007). The sample sites were located in BOPUNJUR, West Java Province. The samples were taken at the selected sites with different levels of urbanization, that is, the least urbanized sites, less urbanized sites, and urbanized sites. In 2006, there are 362 plants species in pekarangans. The result showed that between 1996 and 2006, the size of open space areas of pekarangan decreased, and the number of spesies also became less. However, the number of individual was increased because some plants, especially shrubs and ground covers can reproduce by themselves vegetatively. Some factors that influenced the changes of vegetation structure at pekarangan are (1) small open space area, (2) land fragmentation, (3) different owner, (4) changes in function of some part of the pekarangan, (5) plant popularity trend, and (6) economic condition changes.

Regarding vegetation stratification, it was observed that the first stratum of vegetation such as grasses and herbs was predominant in each level of urbanization, both in 1996 and 2006. In the intervening 10 years, the availability of tree strata was reduced in pekarangan (Fig. 8.1). Most of these factors were thought to be correllated with the impact of urbanization. This study also proposed some actions to utilize pekarangan effectively through a Participatory Rural Appraisal (PRA) approach, such as in plant selection, recycling systems, and revitalizing mixed agroforestry practices.

Fig. 8.1
figure 1

Percentage of individual plant number in each stratum by urbanization level in 1996 (above) and in 2006 (bottom). L-I, the least urbanized area; I-1, I-2, I-3, intermediate urbanized areas; M-1, M-2, the most urbanized area); 1st strata, 0–1 m; 2nd strata, 1–2 m; 3rd strata, 2–5 m; 4th strata, 5–10 m; 5th strata, >10 m

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4.3 Low Carbon in Pekarangan

Pekarangan, a traditional biodiversity–low carbon system in Indonesia to establish green procurement, promote greening, and set green guidelines, species diversity, or biodiversity plays an important role in sustaining the ecosystem at present and in the future (Arifin and Nakagoshi 2011). Pekarangan is a common smallholder agroforestry system in Indonesia and throughout the tropics, from the rural to the urban areas (Arifin 1998). These species-rich, tree-based systems produce non-wood and wood products for both home use and market sale. High biodiversity is an intrinsic property of the home gardens (Kumar 2006), which presumably favors greater net primary productivity (NPP) and higher C sequestration potential than monospecific production systems. Projections by Roshetko et al. (2002) revealed that, depending on management options, the time-averaged above-ground C stocks of pekarangan systems could vary from 30 to 123 Mg C ha−1. These projected time-averaged above-ground C stocks of pekarangans are substantially higher than those of Imperata–cassava systems (2.2 Mg C ha−1), which is an extensive vegetation type in the Lampung study area. Pekarangan research showed these systems simultaneously offer potential for C storage because of their high biomass. Although small size limits the amount of C stored by individual smallholder agroforestry systems, on a per area basis these systems can store as much C as some secondary forests. In aggregate, smallholder pekarangan agroforestry systems can contribute significantly to a regional C budget while simultaneously enhancing smallholder livelihoods. A field study in other areas outside Java Island, that is, Lampung, Indonesia indicates that pekarangans with an average age of 13 years store 35.3 Mg C ha−1 in their above-ground biomass, which is on par with the C stocks reported for similar-aged secondary forests in the same area (Roshetko et al. 2002).

Some experimental evidence also suggests that plant diversity and composition influence the enhancement of biomass and C acquisition in ecosystems subjected to elevated atmospheric CO2 concentrations (Kumar 2006). Reich et al. (2001) reported that biomass accumulation was greater in species-rich than in species-poor experimental populations under conditions of CO2 and N fertilization. By extension, home gardens, which are inherently species rich, may trap progressively greater quantities of atmospheric CO2 under rising levels of this gas.

If pekarangan systems and other smallholder tree-based systems were to expand in currently degraded and underutilized lands, such as Imperata grasslands, the C sequestration potential would be about 80 Mg C ha−1, with considerable variation depending on species composition and management practices. Clearly, opportunity exists to induce management that leads to higher C stocks at the systems level. However, incentive mechanisms are needed that assure smallholders will benefit from selecting management practices that favor higher C stocks (Arifin and Nakagoshi 2011).

5 Summary

Published articles and a dissertation (Arifin 1998) such as those on pekarangan defined that Indonesian home gardens are generally regarded as a complex, species-rich agroforestry system, a diverse mixture of perennial and annual plant species arranged in a multilayered vertical structure, often in combination with raising livestock managed in a sustainable manner over decades or even centuries. A wide spectrum of multiple-use products can be generated with relatively low labor, cash, or other external inputs. In many densely populated tropical regions, pekarangan appear to be the last forest-like islands surrounded by increasingly extended, uniform staple crop fields. Some research sponsored by the Core University Research Program JSPS Japan/DGHE Indonesia, and STORMA Germany (1998–2007), concluded that with their multilayered vegetation structure, pekarangan serves as an important habitat for included wild flora and fauna.

Pekarangan fulfils not only important ecological but also many social and cultural functions (Arifin et al. 1998; Arifin et al. 2001). However, the major purposes of pekarangan are subsistence production and income generation, particularly in rural areas (Kehlenbeck et al. 2007). At forest margins, high production levels in pekarangan might help to reduce deforestation. Furthermore, pekarangan should be considered as a model for sustainable agroforestry systems, integrating both economic and ecological benefits.